KINDAI UNIVERSITY


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SEKIGUCHI Fumiko

Profile

FacultyDepartment of Pharmacy / Graduate School of Medicine
PositionAssociate Professor
Degree
Commentator Guidehttps://www.kindai.ac.jp/meikan/647-sekiguchi-fumiko.html
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Last Updated :2020/08/10

Education and Career

Education

  •  - 1991 , The University of Tokushima, Faculty of Pharmaceutical Sciences
  •  - 1991 , The University of Tokushima, School of Pharmaceutical Sciences

Academic & Professional Experience

  •   2008 04 ,  - 現在, Associate Professor, Pharmacology and Pathophysiology, Kinki University School of Pharmacy
  •   2007 04 ,  - 2008 03 , lecturer, Pharmacology and Pathophysiology, Kinki University School of Pharmacy
  •   2003 04 ,  - 2007 03 , Faculty of Pharmacy, Kindai University
  •   2002 04 ,  - 2003 03 , Faculty of Pharmacy, Kindai University
  •   1991 04 ,  - 2002 03 , Faculty of Pharmacy, Kindai University
  •   2002 ,  - 2003 , Assistant Professor, Dept. Anat. and Physiol.,
  •   2003 , - Assistant Professor, Div. Phisio. and Pathophysiol.,
  •   1991 ,  - 2002 , Instructor, Dept. Anat. and Physiol.,
  • Sch. Pharmaceu. Sci., Kinki Univ.
  • Sch. Pharmaceu. Sci., Kinki Univ.
  • Sch. Pharmaceu. Sci., Kinki Univ.

Research Activities

Research Areas

  • Life sciences, Pharmacology

Research Interests

  • HMGB1, neuropathic pain, hydrogen sulfide, T-type calcium channel, Protection of gastic mucosa, Protease-activated receptor

Published Papers

  • NNC 55-0396, a T-type calcium channel blocker, protects against the brain injury induced by middle cerebral artery occlusion and reperfusion in mice., Matsuda S, Nishikawa H, Fukatsu A, Kurokawa Y, Tsubota M, Sekiguchi F, Tokuyama S, Kawabata A, J Pharmacol Sci., J Pharmacol Sci., 140(2), 193 - 196, Jun. 2019 , Refereed
  • Dietary ascorbic acid restriction in GNL/SMP30-knockout mice unveils the role of ascorbic acid in regulation of somatic and visceral pain sensitivity., Tsubota M, Uebo K, Miki K, Sekiguchi F, Ishigami A, Kawabata A, Biochem Biophys Res Commun., Biochem Biophys Res Commun., 511(3), 705 - 710, Mar. 2019 , Refereed
  • Critical role of Cav3.2 T-type calcium channels in the peripheral neuropathy induced by bortezomib, a proteasome-inhibiting chemotherapeutic agent, in mice., Tomita, S, Sekiguchi, F, Deguchi, T, Miyazaki, T, Ikeda, Y, Tsubota, M, Yoshida, S, Nguyen, H.D, Okada, T, Toyooka, N, Kawabata, A, Toxicology, Toxicology, 413, 33 - 39, Feb. 2019 , Refereed
  • Role of non-macrophage cell-derived HMGB1 in oxaliplatin-induced peripheral neuropathy and its prevention by the thrombin/thrombomodulin system in rodents: negative impact of anticoagulants., Tsubota, M, Fukuda, R, Hayashi, Y, Miyazaki, T, Ueda, S, Yamashita, R, Koike, N, Sekiguchi, F, Wake, H, Wakatsuki, S, Ujiie, Y, Araki, T, Nishibori, M, Kawabata, A, Neuroinflammation, Neuroinflammation, in press, 2019 , Refereed
  • Prenylflavanones as Novel T-Type Calcium Channel Blockers Useful for Pain Therapy, SEKIGUCHI FumikoNguyen H-D, Okada T, Sekiguchi F, Tsubota M, Nishikawa H, Kawabata A, Toyooka N, Nat Prod Commun, Nat Prod Commun, 2019, 1 - 11, 2019 , Refereed
  • Genetic deletion of Cav3.2 T-type calcium channels abolishes H2S-dependent somatic and visceral pain signaling in C57BL/6 mice., Matsui K, Tsubota M, Fukushi S, Koike N, Masuda H, Kasanami Y, Miyazaki T, Sekiguchi F, Ohkubo T, Yoshida S, Mukai Y, Oita A, Takada M, Kawabata A, J Pharmacol Sci., J Pharmacol Sci., 140, 310 - 312, 2019 , Refereed
  • Role of Cav3.2 T-type Ca2+ channels in prostate cancer cells, Fumiko Sekiguchi, Atsufumi Kawabata, Nihon Yakurigaku Zasshi, Nihon Yakurigaku Zasshi, 154(3), 97 - 102, 2019
  • Paclitaxel-induced HMGB1 release from macrophages and its implication for peripheral neuropathy in mice: Evidence for a neuroimmune crosstalk., SEKIGUCHI Fumiko, DOMOTO Risa, NAKASHIMA Kana, YAMASOBA Daichi, YAMANISHI Hiroki, TSUBOTA Maho, WAKE Hidenori, NISHIBORI Masahiro, KAWABATA Atsufumi, Neuropharmacology, Neuropharmacology, 141, 201 - 213, Sep. 2018 , Refereed
  • Blockade of T-type calcium channels by 6-prenylnaringenin, a hop component, alleviates neuropathic and visceral pain in mice., Sekiguchi Fumiko, Fujita Tomoyo, Deguchi Takahiro, Yamaoka Sakura, Tomochika Ken, Tsubota Maho, Ono Sumire, Horaguchi Yamato, Ichii Maki, Ichikawa Mio, Ueno Yumiko, Koike Nene, Tanino Tadatoshi, Nguyen Huy Du, Okada Takuya, Nishikawa Hiroyuki, Yoshida Shigeru, Ohkubo Tsuyako, Toyooka Naoki, Murata Kazuya, Matsuda Hideaki, Kawabata Atsufumi, Neuropharmacology, Neuropharmacology, 138, 232 - 244, Aug. 2018 , Refereed
  • Design and synthesis of novel anti-hyperalgesic agents based on 6-prenylnaringenin as the T-type calcium channel blockers., Du Nguyen Huy, Okada Takuya, Kitamura Shum, Yamaoka Sakura, Horaguchi Yamato, Kasanami Yoshihito, Sekiguchi Fumiko, Tsubota Maho, Yoshida Shigeru, Nishikawa Hiroki, Kawabata Atsufumi, Toyooka Naoki, Bioorg Med Chem., Bioorg Med Chem., 19, 4410 - 4427, Jul. 2018 , Refereed
  • Human soluble thrombomodulin-induced blockade of peripheral HMGB1-dependent allodynia in mice requires both the lectin-like and EGF-like domains., Hayashi Y, Tsujita R, Tsubota M, Saeki H, Sekiguchi F, Honda G, Kawabata A, Biochem Biophys Res Commun., Biochem Biophys Res Commun., 495(1), 634 - 638, Jun. 2018 , Refereed
  • Role of Thrombin in Soluble Thrombomodulin-Induced Suppression of Peripheral HMGB1-Mediated Allodynia in Mice., Tsujita R, Tsubota M, Hayashi Y, Saeki H, Sekiguchi F, Kawabata, A. Role, of Thrombin in, Soluble Thrombomodulin-Induced Suppressio, J Neuroimmune Pharmacol., J Neuroimmune Pharmacol., 13(2), 179 - 188, Jun. 2018 , Refereed
  • Involvement of the cystathionine-γ-lyase/Cav3.2 pathway in substance P-induced bladder pain in the mouse, a model for nonulcerative bladder pain syndrome., Tsubota M, Okawa Y, Irie Y, Maeda M, Ozaki T, Sekiguchi F, Ishikura H, Kawabata A, Neuropharmacology, Neuropharmacology, 133, 254 - 263, May 2018 , Refereed
  • Involvement of NF-κB in the upregulation of cystathionine-γ-lyase, a hydrogen sulfide-forming enzyme, and bladder pain accompanying cystitis in mice., Ozaki T, Tsubota M, Sekiguchi F, Kawabata A, Clin Exp Pharmacol Physiol., Clin Exp Pharmacol Physiol., 45(4), 355 - 361, Apr. 2018 , Refereed
  • Zinc deficiency promotes cystitis-related bladder pain by enhancing function and expression of Cav3.2 in mice., Ozaki T, Matsuoka J, Tsubota M, Tomita S, Sekiguchi F, Minami T, Kawabata A, Toxicology, Toxicology, 393, 102 - 112, Jan. 2018 , Refereed
  • Prostanoid-dependent bladder pain caused by proteinase-activated receptor-2 activation in mice: Involvement of TRPV1 and T-type Ca2+ channels., Tsubota M, Ozaki T, Hayashi Y, Okawa Y, Fujimura A, Sekiguchi F, Nishikawa H, Kawabata A, J Pharmacol Sci., J Pharmacol Sci., 136(1), 46 - 49, Jan. 2018 , Refereed
  • Involvement of Voltage-Gated Calcium Channels in Inflammation and Inflammatory Pain., Sekiguchi F, Tsubota M, Kawabata A, Biol Pharm Bull., Biol Pharm Bull., 41(8), 1127 - 1134, 2018
  • Functional regulation of ion channels by H2S and its pathological impact, SEKIGUCHI Fumiko, KAWABATA Atsufumi, 70(5), 61 - 70, May 2017
  • Tacrolimus triggers TRPV1-dependent relapse of pancreatitis-related pain in mice, Terada Y, Tsubota M, Sugo H, Wakitani K, Sekiguchi F, Wada K, Takada M, Oita A, Kawabata A, Pharmacology, Pharmacology, 99, 281 - 285, Mar. 2017 , Refereed
  • Macrophage-derived HMGB1 as a Pain Mediator in the Early Stage of Acute Pancreatitis in Mice: Targeting RAGE and CXCL12/CXCR4 Axis., Irie Y, Tsubota M, Ishikura H, Sekiguchi F, Terada Y, Tsujiuchi T, Liu K, Nishibori M, Kawabata A, J Neuroimmune Pharmacol., J Neuroimmune Pharmacol., in press, 2017 , Refereed
  • Hydrogen sulfide and T-type Ca2+ channels in pain processing, neuronal differentiation and neuroendocrine secretion., Fukami K, Sekiguchi F, Kawabata A, Pharmacology, Pharmacology, 99, 107 - 114, 2017 , Refereed
  • Recombinant human soluble thrombomodulin prevents peripheral HMGB1-dependent hyperalgesia in rats., Tanaka J, Seki Y, Ishikura H, Tsubota M, Sekiguchi F, Yamaguchi K, Murai A, Umemura T, Kawabata A, Br J Pharmacol., Br J Pharmacol., 170, 1233 - 1241, Nov. 2013 , Refereed
  • Inhibition by hydrogen sulfide of rabbit platelet aggregation and calcium mobilization., Nishikawa H, Hayashi H, Kubo S, Tsubota-Matsunami M, Sekiguchi F, Kawabata A, Biol Pharm Bull., Biol Pharm Bull., 36(8), 1278 - 1282, Aug. 2013 , Refereed
  • Antihyperalgesic effect of buprenorphine involves nociceptin/orphanin FQ peptide-receptor activation in rats with spinal nerve injury-induced neuropathy., Takahashi T, Okubo K, Kojima S, Nishikawa H, Takemura M, Tsubota-Matsunami M, Sekiguchi F, Kawabata A, J Pharmacol Sci., J Pharmacol Sci., 122(1), 51 - 54, Apr. 2013 , Refereed
  • Biological activity of Helicobacter pylori components in mammalian cells: is it independent of proteinase-activated receptors?, Sekiguchi F, Matsumoto Y, Maeda Y, Tsubota-Matsunami M, Nishikawa H, Kawabata A, J Physiol Pharmacol., J Physiol Pharmacol., 63(6), 571 - 716, 2012 , Refereed
  • Curcumin Inhibits the Proteinase-Activated Receptor-2-Triggered Prostaglandin E-2 Production by Suppressing Cyclooxygenase-2 Upregulation and Akt-Dependent Activation of Nuclear Factor-kappa B in Human Lung Epithelial Cells, Kazumi Moriyuki, Fumiko Sekiguchi, Kaori Matsubara, Hiroyuki Nishikawa, Atsufumi Kawabata, JOURNAL OF PHARMACOLOGICAL SCIENCES, JOURNAL OF PHARMACOLOGICAL SCIENCES, 114(2), 225 - 229, Oct. 2010
    Summary:We performed this study to determine if curcumin affects pro-inflammatory responses to activation of proteinase-activated receptor-2 (PAR2) in human pulmonary adenocarcinoma A549 cells. Curcumin completely inhibited the PAR2-triggered prostaglandin E-2 (PGE(2)) production, but notably not interleukin-8 release. Cyclooxygenase-2 (COX-2) upregulation, but not its upstream activation of mitogen-activated protein kinases, caused by PAR2 stimulation was partially inhibited by curcumin. Curcumin inhibited the PAR2-triggered phosphorylation of I-kappa B, an indicator for nuclear factor-kappa B (NF-kappa B) activation, and also its upstream signal Akt, which is known to contribute to PAR2-triggered PGE2 formation, but not COX-2 upregulation. Collectively, curcumin inhibits the PAR2-triggered PGE2 production by suppressing COX-2 upregulation and Akt/NF-kappa B signals in A549 cells.
  • Curcumin Inhibits the Proteinase-Activated Receptor-2-Triggered Prostaglandin E-2 Production by Suppressing Cyclooxygenase-2 Upregulation and Akt-Dependent Activation of Nuclear Factor-kappa B in Human Lung Epithelial Cells, Kazumi Moriyuki, Fumiko Sekiguchi, Kaori Matsubara, Hiroyuki Nishikawa, Atsufumi Kawabata, JOURNAL OF PHARMACOLOGICAL SCIENCES, JOURNAL OF PHARMACOLOGICAL SCIENCES, 114(2), 225 - 229, Oct. 2010 , Refereed
    Summary:We performed this study to determine if curcumin affects pro-inflammatory responses to activation of proteinase-activated receptor-2 (PAR2) in human pulmonary adenocarcinoma A549 cells. Curcumin completely inhibited the PAR2-triggered prostaglandin E-2 (PGE(2)) production, but notably not interleukin-8 release. Cyclooxygenase-2 (COX-2) upregulation, but not its upstream activation of mitogen-activated protein kinases, caused by PAR2 stimulation was partially inhibited by curcumin. Curcumin inhibited the PAR2-triggered phosphorylation of I-kappa B, an indicator for nuclear factor-kappa B (NF-kappa B) activation, and also its upstream signal Akt, which is known to contribute to PAR2-triggered PGE2 formation, but not COX-2 upregulation. Collectively, curcumin inhibits the PAR2-triggered PGE2 production by suppressing COX-2 upregulation and Akt/NF-kappa B signals in A549 cells.
  • Proteinase-Activated Receptor-2-Triggered Prostaglandin E-2 Release, but Not Cyclooxygenase-2 Upregulation, Requires Activation of the Phosphatidylinositol 3-Kinase/Akt/Nuclear Factor-kappa B Pathway in Human Alveolar Epithelial Cells, Kazumi Moriyuki, Fumiko Sekiguchi, Kaori Matsubara, Hiroyuki Nishikawa, Atsufumi Kawabata, JOURNAL OF PHARMACOLOGICAL SCIENCES, JOURNAL OF PHARMACOLOGICAL SCIENCES, 111(3), 269 - 275, Nov. 2009
    Summary:Proteinase-activated receptor-2 (PAR2) triggers upregulation of cyclooxygenase-2 (COX-2) and prostaglandin E-2 (PGE(2)) formation in human alveolar epithelial A549 cells. This COX-2 upregulation appears to involve the Src/epidermal growth factor (EGF) receptor/p38 MAP kinase (p38MAPK) pathway and also the cAMP-response element-binding protein (CREB) pathway. Here, we investigated the roles of nuclear factor-kappa B (NF-kappa B)-related signals in the PAR2-triggered PGE(2) release/COX-2 upregulation in A549 cells. The PAR2-triggered PGE2 release was clearly blocked by an inhibitor of the NF-kappa B pathway. Stimulation of PAR2 actually caused phosphorylation of inhibitor-kappa B, an indicator of NF-kappa B activation, an effect being blocked by inhibitors of MEK, phosphatidylinositol 3-kinase (PI3-kinase), and Akt, but little or not by inhibitors of p38MAPK and JNK. Stimulation of PAR2 also caused phosphorylation of Akt, an effect suppressed by inhibitors of PI3-kinase and MEK. Nonetheless, the PAR2-triggered upregulation of COX-2 was resistant to inhibitors of NF-kappa B, PI3-kinase, and Akt, but was attenuated by inhibitors of MEK and JNK. Stimulation of PAR2 induced phosphorylation of CREB, an effect abolished by an inhibitor of MEK but not inhibitors of p38MAPK and EGF receptor. These findings demonstrate that the MEK / ERK / PI3-kinase / Akt / NF-kappa B pathway is involved in PAR2-triggered PGE2 formation, but not upregulation of COX-2 that is dependent on activation of ERK/CREB and JNK in addition to p38MAPK.
  • Rhodanese, but not cystathionine-gamma-lyase, is associated with dextran sulfate sodium-evoked colitis in mice: A sign of impaired colonic sulfide detoxification?, Eiichi Taniguchi, Maho Matsunami, Takeshi Kimura, Daiki Yonezawa, Tsuyoshi Ishiki, Fumiko Sekiguchi, Hiroyuki Nishikawa, Yuma Maeda, Hiroyasu Ishikura, Atsufumi Kawabata, TOXICOLOGY, TOXICOLOGY, 264(1-2), 96 - 103, Oct. 2009 , Refereed
    Summary:Clinical studies suggest that colonic luminal hydrogen sulfide (H(2)S), produced by sulfate-reducing bacteria or through other pathways, might be involved in the pathogenesis of inflammatory bowel disease (IBD). Nonetheless, this hypothesis has been poorly investigated by basic studies using laboratory animals. We thus focused on two enzymes, cystathionine-gamma-lyase (CSE) that generates H(2)S from L-cysteine, and rhodanese that directly or indirectly detoxifies H(2)S, particularly in relation to the colitis induced by dextran sulfate sodium (DSS) in mice. CSE was a major H(2)S-forming enzyme in colonic and renal homogenates from mice and rats, and the rhodanese activity was also detectable in both tissues. Colitis-related symptoms including decreased body weight gain, diarrhea, hematochezia and shortening of colon length were observed in the mice drinking DSS. Those symptoms were not or only slightly attenuated by repeated administration of a CSE inhibitor. CSE activity and protein levels in the colonic tissue did not notably change in the mice with colitis. In contrast, the activity and protein/mRNA levels of rhodanese in the colon, but not kidney, significantly decreased nearly in parallel with the development of colitis, followed by elevation of rhodanese activity in red blood cells (RBCs). These data show that rhodanese, but not CSE, is associated with DSS-induced colitis in mice, leading to a hypothesis that impaired detoxification of H(2)S due to down-regulation or suppression of colonic rhodanese is involved in IBD. The delayed enhancement of rhodanese activity in RBCs, a possible compensative event, might be available as a disease marker for IBD. (C) 2009 Elsevier Ireland Ltd. All rights reserved.
  • Proteinase-activated receptors in the gastrointestinal system: a functional linkage to prostanoids., Sekiguchi F, Takaoka K, Kawabata A, Inflammopharmacology, Inflammopharmacology, 15(6), 246 - 251, Dec. 2007 , Refereed
  • Distinct activity of peptide mimetic intracellular ligands (pepducins) for proteinase-activated receptor-1 in multiple cells/tissues, Kubo S, Ishiki T, Doe I, Sekiguchi F, Nishikawa H, Kawai K, Matsui H, Kawabata A, Ann N Y Acad Sci, Ann N Y Acad Sci, 1091, 115 - 459, Dec. 2006 , Refereed
  • Development of agonists/antagonists for protease-activated receptors (PARs) and the possible therapeutic application to gastrointestinal diseases, F Sekiguchi, YAKUGAKU ZASSHI-JOURNAL OF THE PHARMACEUTICAL SOCIETY OF JAPAN, YAKUGAKU ZASSHI-JOURNAL OF THE PHARMACEUTICAL SOCIETY OF JAPAN, 125(6), 491 - 498, Jun. 2005 , Refereed
    Summary:Protease-activated receptors (PARs), a family of G-protein-coupled seven-transmembrane-domain receptors, are activated by proteolytic unmasking of the N-terminal cryptic tethered ligand by certain serine proteases. Among four PAR family members cloned to date, PAR-1, PAR-2, and PAR-4 can also be activated through a non-enzymatic mechanism, which is achieved by direct binding of exogenously applied synthetic peptides based on the tethered ligand sequence, known as PARs-activating peptides, to the body of the receptor. Various peptide mimetics have been synthesized as agonists for PARs with improved potency, selectivity, and stability. Some peptide mimetics and/or nonpeptide compounds have also been developed as antagonists for PAR-1 and PAR-4. PARs are widely distributed in the mammalian body, especially throughout the alimentary systems, and play various roles in physiological/pathophysiological conditions, i.e., modulation of salivary, gastric, or pancreatic glandular exocrine secretion, gastrointestinal smooth muscle motility, gastric mucosal cytoprotection, suppression/facilitation of visceral pain and inflammation, etc. Thus PARs are now, considered novel therapeutic targets, and development of selective agonists and/or antagonists for PARs might provide a novel strategy for the treatment of various diseases that are resistant to current therapeutics.
  • Effect of a potent iNOS inhibitor (ONO-1714) on acetaminophen-induced hepatotoxicity in the rat, Y Kamanaka, A Kawabata, H Matsuya, C Taga, F Sekiguchi, N Kawao, LIFE SCIENCES, LIFE SCIENCES, 74(6), 793 - 802, Dec. 2003
    Summary:Overproduction of nitric oxide (NO) in the liver has been implicated as an important event in endotoxin shock and in other models of hepatic inflammation and injury. The present study was undertaken to evaluate the effect of ONO-1714, a potent and specific inhibitor of inducible NO synthase (iNOS), on acetaminophen-induced hepatotoxicity in the rats. Oral administration of ONO-1714 dose-dependently inhibited NOx (NO2 and NO3-) accumulation in rat plasma after lipopolysaccharide (LPS) treatment. Intraperitoneal acetaminophen at 1 g/kg caused damage to the centrilobular regions of the liver and increase in serum alanine and aspartate transaminase (ALT and AST, respectively) levels accompanied by elevated plasma NOx levels after 24 h. Oral administration of ONO-1714 at 10 and 100 mug/kg dose-dependently reduced the acetaminophen-induced hepatic tissue damage and the increases in serum ALT and AST levels. ONO-1714 also blocked the increase in plasma NOx concentrations. These findings demonstrate that oral ONO-1714, an iNOS inhibitor, protects against acetaminophen-evoked hepatic inflammation/injury, strongly suggesting that NO produced by iNOS plays a key role in the pathogenesis of this drug-induced hepatotoxicity. (C) 2003 Elsevier Inc. All rights reserved.
  • The PAR-1-activating peptide facilitates pepsinogen secretion in rats, N Kawao, K Hiramatsu, N Inoi, R Kuroda, H Nishikawa, F Sekiguchi, A Kawabata, PEPTIDES, PEPTIDES, 24(9), 1449 - 1451, Sep. 2003
    Summary:Protease-activated receptor-2 (PAR-2) is abundantly expressed in gastric mucosal chief cells, facilitating pepsinogen secretion. In the present study, we investigated whether PAR-1, a thrombin receptor, could modulate pepsinogen secretion in rats. The PAR-1-activating peptide TFLLR-NH2 as well as the PAR-2-activating peptide SLIGRL-NH2, administered i.v. repeatedly at 1-h intervals, significantly increased gastric pepsinogen secretion over 2-4 h (after two to four doses). In contrast, the control peptide FTLLR-NH2, given in the same manner, had no such effect. Thus, PAR-1, like PAR-2, might function to facilitate pepsinogen secretion, suggesting a novel role of the thrombin-PAR-1-pathway in the stomach. (C) 2003 Elsevier Inc. All rights reserved.
  • Endothelium-derived relaxing factor - nitric oxide and hypertension., SUNANO Satoru, SEKIGUCHI Fumiko, Yakugaku Zasshi, Yakugaku Zasshi, 123(7), 495 - 515, Jun. 2003
  • Gastric relaxation by inhibitory neurotransmitters in hypertensive rats, SHIMAMURA Keiichi, KIMURA S, SEKIGUCHI Fumiko, SUNANO Satoru, SAITO H, Biomed. Res., Biomed. Res., 14(1), 62 - 69, Apr. 2003 , Refereed
  • Caffeine-induced relaxation is unimpaired in the aorta of stroke-prone spontaneously hypertensive rats(SHRSP), 11, 131 - 142, Mar. 2003
  • Symposium for Smooth Muscle and Vascular Endothelium., Sekiguchi F, Journal of smooth muscle research = Nihon Heikatsukin Gakkai kikanshi, Journal of smooth muscle research = Nihon Heikatsukin Gakkai kikanshi, 39(6), 229, 2003 , Refereed
  • Effects of drugs which act on the sarcoplasmic reticulum in the esophageal striated muscles from normotensive and spontaneously hypertensive rats, 23(4・5), 131 - 144, Dec. 2002
  • Hypertension and impairment of endothelium dependent relaxation of arteries from spontaneously hypertensive and L NAME treated Wistar rats, (10), 33 - 45, Mar. 2002
  • Arterial smooth muscle tone and its modification by endothelium in spontaneously hypertensive rats., SUNANO Satoru, SEKIGUCHI Fumiko, SHIMAMURA Keiichi, Biomed. Res., Biomed. Res., 11, 137 - 147, 2000 , Refereed
  • Abnormality of the endothelium-dependent and -independent tension oscillation in the artery of spontaneously hypertensive rats., SHIMAMURA Keiichi, SEKIGUCHI Fumiko, SUNANO Satoru, J. Smooth Muscle Res. (Japanese Section),, J. Smooth Muscle Res. (Japanese Section),, 2, J-99 - J116, 1999
  • Abnormality of hyperpolarization and relaxation mediated by the endothelium-derived factors in spontaneously hypertensive rats, SUNANO Satoru, SEKIGUCHI Fumiko, MATSUDA Kyoko, SHIMAMURA Keiichi, J. Smooth Muscle Res. (Japanese Section),, J. Smooth Muscle Res. (Japanese Section),, 1, J-101 - J-116, 1997
  • Blood pressure and age-dependent changes of endothelium-dependent tension oscillations in different strains of spontaneously hypertensive rats., Shimamura, K, Matsuda, K, Sekiguchi, F, Sunano, S, J. Smooth Muscle Res., J. Smooth Muscle Res., 32, 145 - 154, Aug. 1996 , Refereed
  • Effect of cyclopiazonic acid and thapsigargin on electromechanical activities and intracellular Ca2+ in smooth muscle of carotid artery of hypertensive rats., Sekiguchi, F, Shimamura, K, Akashi, M, Sunano, S, Br J Pharmacol., Br J Pharmacol., 118(4), 857 - 864, Jun. 1996 , Refereed
  • Endothelium-Dependent relaxation by alpha(2)-adrenoceptor agonists in spontaneously hypertensive rat aorta, S Sunano, LB Zou, K Matsuda, F Sekiguchi, H Watanabe, K Shimamura, JOURNAL OF CARDIOVASCULAR PHARMACOLOGY, JOURNAL OF CARDIOVASCULAR PHARMACOLOGY, 27(5), 733 - 739, May 1996 , Refereed
    Summary:Differences in alpha(2)-adrenoceptor-induced relaxation of the aorta between stroke-prone spontaneously hypertensive rats (SHRSP) and control normotensive Wistar Kyoto rats (WKY) were studied. Changes in the tension of ring preparations of the aortas were measured isometrically. Relaxation was observed in the preparations precontracted in the presence of ONO-11113. a thromboxane A(2) analogue. The alpha(2)-agonist clonidine and UK-14304 induced dose-dependent relaxation in both the WKY and HRP preparations. The relaxation was impaired in the SHRSP preparation. A modified sandwich experiment showed that the relaxing substance from the SHRSP endothelium was decreased. Acetylcholine (ACh) also induced dose-dependent relaxation, and the relaxation was impaired in the SHRSP preparations. alpha(2)-Agonists induced a greater degree of impairment in the relaxation than did ACh. The relaxation induced by alpha(2)-agonists and by ACh was blocked by N-G-nitro-L-arginine (L-NNA). Indomethacin improved the relaxation induced by ACh but not that induced by alpha(2)-agonisrs in the SHRSP aortas. These results suggest that the impairment of relaxation by alpha(2)-agonists in SHRSP is not caused by the increase in the release of endothelium-derived contracting factor (EDCF) but by the reduction in the release of nitric oxide (NO). Alteration of the alpha(2)-adrenoceptors and/or the intracellular mechanism through which NO is synthesized by stimulation of the alpha(2)-adrenoceptors may be the cause of the reduction in relaxation.
  • Neural responses of rat abdominal skin artery., Shimamura, K, Akagi, K, Yamamoto, K, Sekiguchi, F, Sunano, S, J. Smooth Muscle Res., J. Smooth Muscle Res., 31, 397 - 399, Dec. 1995 , Refereed
  • Comparison of endothelium-dependent and –independent tension oscillation in aortae of stroke-prone spontaneously hypertensive and Wistar Kyoto rats., Sunano, S, Sasaki, F. (now, SEKIGUCHI Fumiko, Osugi, S, Shimamura, K, J. Smooth Muscle Res., J. Smooth Muscle Res., 30, 135 - 145, Aug. 1995 , Refereed
  • Effects of NG-nitro-L-arginine on α2-agonists-induced contraction of aortae from Wistar Kyoto rats and stroke-prone spontaneously hypertensive rats., Matsuda, K, Sekiguchi, F. (now, SEKIGUCHI Fumiko, Tojo, M, Shimamura, K, Sunano, S, J. Smooth Muscle Res., J. Smooth Muscle Res., 31, 51 - 60, Apr. 1995 , Refereed
  • Relationship between blood pressure and smooth muscle tone in aorta of hypertensive rats: roles of [Ca2+]., Sasaki, F. (now, SEKIGUCHI Fumiko, Osugi, S, Shimamura, K, Sunano, S, J. Smooth Muscle Res., J. Smooth Muscle Res., 29, 69 - 79, 1993 , Refereed
  • Effect of treatment on the enhanced spontaneous tonus in the arterial smooth muscle of spontaneously hypertensive rats., SUNANO Satoru, SASAKI Fumiko (no, SEKIGUCHI Fumiko, J. Smooth Muscle Res. (Japanese Section),, J. Smooth Muscle Res. (Japanese Section),, 29, 111 - 130, 1993
  • Repeated Cold Stress Reduces Cyclophosphamide-Induced Cystitis/Bladder Pain and Macrophage Activity in Mice, Maho Tsubota, Tomoyoshi Miyamoto, Saki Hiruma, Haruka Saeki, Takaya Miyazaki, Fumiko Sekiguchi, Yoshinori Funakami, Atsufumi Kawabata, PHARMACOLOGY, PHARMACOLOGY, 99(5-6), 286 - 290, 2017 , Refereed
    Summary:We examined the effect of repeated cold (RC) stress on cyclophosphamide (CPA)-induced cystitis/bladder pain in mice, in relation to macrophage activity. CPA, given i.p. at 400 mg/kg, caused bladder pain symptoms accompanying cystitis in both unstressed and RC-stressed mice, which were prevented by the macrophage inhibitor minocycline. A low dose, that is, 200 mg/kg, of CPA still produced bladder pain symptoms in unstressed but not RC-stressed mice. Lipopoly-saccharide-induced cytokine production in peritoneal macrophages from RC-stressed mice was less than that from unstressed mice. Thus, RC stress appears to reduce CPA-induced bladder pain in mice, which may be associated with the decreased macrophage activity. (C) 2017 S. Karger AG, Basel
  • High glucose induces N-linked glycosylation-mediated functional upregulation and overexpression of Ca(v)3.2 T-type calcium channels in neuroendocrine-like differentiated human prostate cancer cells, Kazuki Fukami, Erina Asano, Mai Ueda, Fumiko Sekiguchi, Shigeru Yoshida, Atsufumi Kawabata, JOURNAL OF PHARMACOLOGICAL SCIENCES, JOURNAL OF PHARMACOLOGICAL SCIENCES, 133(1), 57 - 60, Jan. 2017 , Refereed
    Summary:Given that Ca(v)3.2 T-type Ca2+ channels were functionally regulated by asparagine (N)-linked glycosylation, we examined effects of high glucose on the function of Ca(v)3.2, known to regulate secretory function, in neuroendocrine-like differentiated prostate cancer LNCaP cells. High glucose accelerated the increased channel function and overexpression of Ca(v)3.2 during neuroendocrine differentiation, the former prevented by enzymatic inhibition of N-glycosylation and cleavage of N-glycans. Hyperglycemia thus appears to induce N-linked glycosylation-mediated functional upregulation and overexpression of Ca(v)3.2 in neuroendocrine-like differentiated prostate cancer cells. (C) 2017 The Authors. Production and hosting by Elsevier B.V. on behalf of Japanese Pharmacological Society. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
  • Therapeutic potential of RQ-00311651, a novel T-type Ca2+ channel blocker, in distinct rodent models for neuropathic and visceral pain, Fumiko Sekiguchi, Yuma Kawara, Maho Tsubota, Eri Kawakami, Tomoka Ozaki, Yudai Kawaishi, Shiori Tomita, Daiki Kanaoka, Shigeru Yoshida, Tsuyako Ohkubo, Atsufumi Kawabata, PAIN, PAIN, 157(8), 1655 - 1665, Aug. 2016 , Refereed
    Summary:T-type Ca2+ channels (T channels), particularly Ca(v)3.2 among the 3 isoforms, play a role in neuropathic and visceral pain. We thus characterized the effects of RQ-00311651 (RQ), a novel T-channel blocker, in HEK293 cells transfected with human Ca(v)3.1 or Ca(v)3.2 by electrophysiological and fluorescent Ca2+ signaling assays, and also evaluated the antiallodynic/antihyperalgesic activity of RQ in somatic, visceral, and neuropathic pain models in rodents. RQ-00311651 strongly suppressed T currents when tested at holding potentials of -65 similar to - 260 mV, but not -80 mV, in the Ca(v)3.1- or Ca(v)3.2-expressing cells. RQ-00311651 also inhibited high K+-induced Ca2+ signaling in those cells. In mice, RQ, administered intraperitoneally (i.p.) at 5 to 20 mg/kg or orally at 20 to 40 mg/kg, significantly suppressed the somatic hyperalgesia and visceral pain-like nociceptive behavior/referred hyperalgesia caused by intraplantar and intracolonic administration of NaHS or Na2S, H2S donors, respectively, which involve the enhanced activity of Ca(v)3.2 channels. RQ-00311651, given i.p. at 5 to 20 mg/kg, exhibited antiallodynic or antihyperalgesic activity in rats with spinal nerve injury-induced neuropathy or in rats and mice with paclitaxel-induced neuropathy. Oral and i.p. RQ at 10 to 20 mg/kg also suppressed the visceral nociceptive behavior and/or referred hyperalgesia accompanying cerulein-induced acute pancreatitis and cyclophosphamide-induced cystitis in mice. The analgesic and antihyperalgesic/antiallodynic doses of oral and i.p. RQ did not significantly affect the locomotor activity and motor coordination. Together, RQ is considered a state-dependent blocker of Ca(v)3.1/Ca(v)3.2 T channels and may serve as an orally available analgesic for treatment of neuropathic and inflammatory pain including distinct visceral pain with minimum central side effects.
  • Involvement of high mobility group box 1 in the development and maintenance of chemotherapy-induced peripheral neuropathy in rats, Takeshi Nishida, Maho Tsubota, Yudai Kawaishi, Hiroki Yamanishi, Natsuki Kamitani, Fumiko Sekiguchi, Hiroyasu Ishikura, Keyue Liu, Masahiro Nishibori, Atsufumi Kawabata, TOXICOLOGY, TOXICOLOGY, 365, 48 - 58, Jul. 2016 , Refereed
    Summary:Given that high mobility group box 1 (HMGB1), a nuclear protein, once released to the extracellular space, promotes nociception, we asked if inactivation of HMGB1 prevents or reverses chemotherapy-induced painful neuropathy in rats and also examined possible involvement of Toll-like receptor 4 (TLR4) and the receptor for advanced glycation endproduct (RAGE), known as targets for HMGB1. Painful neuropathy was produced by repeated i.p. administration of paclitaxel or vincristine in rats. Nociceptive threshold was determined by the paw pressure method and/or von Frey test in the hindpaw. Tissue protein levels were determined by immunoblotting. Repeated i.p. administration of the anti-HMGB1-neutralizing antibody or recombinant human soluble thrombomodulin (rhsTM), known to inactivate HMGB1, prevented the development of hyperalgesia and/or allodynia induced by paclitaxel or vincristine in rats. A single i.p. or intraplantar (i.pl.) administration of the antibody or rhsTM reversed the chemotherapy induced neuropathy. A single i.pl. administration of a TLR4 antagonist or low molecular weight heparin, known to inhibit RAGE, attenuated the hyperalgesia caused by i.pl. HMGB1 and also the chemotherapy induced painful neuropathy. Paclitaxel or vincristine treatment significantly decreased protein levels of HMGB1 in the dorsal root ganglia, but not sciatic nerves. HMGB1 thus participates in both development and maintenance of chemotherapy-induced painful neuropathy, in part through RAGE and TLR4. HMGB1 inactivation is considered useful to prevent and treat the chemotherapy-induced painful neuropathy. (C) 2016 Elsevier Ireland Ltd. All rights reserved.
  • Endogenous Hydrogen Sulfide Enhances Cell Proliferation of Human Gastric Cancer AGS Cells, Fumiko Sekiguchi, Teruki Sekimoto, Ayaka Ogura, Atsufumi Kawabata, BIOLOGICAL & PHARMACEUTICAL BULLETIN, BIOLOGICAL & PHARMACEUTICAL BULLETIN, 39(5), 887 - 890, May 2016 , Refereed
    Summary:Hydrogen sulfide (H2S), the third gasotransmitter, is endogenously generated by certain H2S synthesizing enzymes, including cystathionine-gamma-lyase (CSE) and cystathionine-beta-synthase (CBS) from L-cysteine in the mammalian body. Several studies have shown that endogenous and exogenous H2S affects the proliferation of cancer cells, although the effects of H2S appear to vary with cell type, being either promotive or suppressive. In the present study, we determined whether endogenously formed H2S regulates proliferation in human gastric cancer AGS cells. CSE, but not CBS, was expressed in AGS cells. CSE inhibitors, DL-propargylglycine (PPG) and beta-cyano-L-alanine (BCA), significantly suppressed the proliferation of AGS cells in a concentration-dependent manner. CSE inhibitors did not increase lactate dehydrogenase (LDH) release in the same concentration range. The inhibitory effects of PPG and BCA on cell proliferation were reversed by repetitive application of NaHS, a donor of H2S. Interestingly, nuclear condensation and fragmentation were detected in AGS cells treated with PPG or BCA. These results suggest that endogenous H2S produced by CSE may contribute to the proliferation of gastric cancer AGS cells, most probably through anti-apoptotic actions.
  • The prostaglandin E-2/EP4 receptor/cyclic AMP/T-type Ca2+ channel pathway mediates neuritogenesis in sensory neuron-like ND7/23 cells, Kenji Mitani, Fumiko Sekiguchi, Takashi Maeda, Yukari Tanaka, Shigeru Yoshida, Atsufumi Kawabata, JOURNAL OF PHARMACOLOGICAL SCIENCES, JOURNAL OF PHARMACOLOGICAL SCIENCES, 130(3), 177 - 180, Mar. 2016 , Refereed
    Summary:We investigated mechanisms for the neuritogenesis caused by prostaglandin E-2 (PGE(2)) or intracellular cyclic AMP (cAMP) in sensory neuron-like ND7/23 cells. PGE(2) caused neuritogenesis, an effect abolished by an EP4 receptor antagonist or inhibitors of adenylyl cyclase (AC) or protein kinase A (PKA) and mimicked by the AC activator forskolin, dibutyryl cAMP (db-cAMP), and selective activators of PKA or Epac. ND7/23 cells expressed both Ca(v)3.1 and Ca(v)3.2 T-type Ca2+ channels (T-channels). The neuritogenesis induced by db-cAMP or PGE(2) was abolished by T-channel blockers. T-channels were functionally upregulated by db-cAMP. The PGE(2)/EP4/cAMP/T-channel pathway thus appears to mediate neuritogenesis in sensory neurons. (C) 2016 Japanese Pharmacological Society. Production and hosting by Elsevier B.V.
  • Peripheral HMGB1-induced hyperalgesia in mice: Redox state-dependent distinct roles of RAGE and TLR4, Daichi Yamasoba, Maho Tsubota, Risa Domoto, Fumiko Sekiguchi, Hiroyuki Nishikawa, Keyue Liu, Masahiro Nishibori, Hiroyasu Ishikura, Tetsushi Yamamoto, Atsushi Taga, Atsufumi Kawabata, JOURNAL OF PHARMACOLOGICAL SCIENCES, JOURNAL OF PHARMACOLOGICAL SCIENCES, 130(2), 139 - 142, Feb. 2016 , Refereed
    Summary:Nuclear HMGB1 that contains 3 cysteine residues is acetylated and secreted to the extracellular space, promoting inflammation via multiple molecules such as RAGE and TLR4. We thus evaluated and characterized the redox state-dependent effects of peripheral HMGB1 on nociception. Intraplantar (i.pl.) administration of bovine thymus-derived HMGB1 (bt-HMGB1), all-thiol HMGB1 (at-HMGB1) or disulfide HMGB1 (ds-HMGB1) caused long-lasting mechanical hyperalgesia in mice. The hyperalgesia following i.pl. bt-HMGB1 or at-HMGB1 was attenuated by RAGE inhibitors, while the ds-HMGB1-induced hyperalgesia was abolished by a TLR4 antagonist. Thus, nociceptive processing by peripheral HMGB1 is considered dependent on its redox states. (C) 2016 Japanese Pharmacological Society. Production and hosting by Elsevier B.V.
  • Selective sensitization of C-fiber nociceptors by hydrogen sulfide, Yuka Aoki, Maho Tsubota, Yuta Nishimoto, Yumi Maeda, Fumiko Sekiguchi, Atsufumi Kawabata, JOURNAL OF PHARMACOLOGICAL SCIENCES, JOURNAL OF PHARMACOLOGICAL SCIENCES, 130(1), 38 - 41, Jan. 2016 , Refereed
    Summary:We examined the effects of intraplantar (i.pl.) administration of NaHS, an H2S donor, known to cause T-type Ca2+ channel (T-channel)-dependent mechanical hyperalgesia, on responsiveness to electric stimulation with 5, 250 and 2000 Hz sine waves (SW) that selectively excites C, A delta and A beta fibers, respectively. NaHS, given i.pl., caused behavioral hypersensitivity to SW stimulation at 5 Hz, but not 250 or 2000 Hz, in rats. NaHS also enhanced phosphorylation of spinal ERK following 5 Hz SW stimulation. Three distinct T-channel blockers abolished the NaHS-induced behavioral hypersensitivity to 5 Hz SW stimulation. Thus, H2S selectively sensitizes C-fiber nociceptors via T-channels. (C) 2016 Japanese Pharmacological Society. Production and hosting by Elsevier B.V.
  • Functional upregulation of the H2S/Ca(v)3.2 channel pathway accelerates secretory function in neuroendocrine-differentiated human prostate cancer cells, Kazuki Fukami, Fumiko Sekiguchi, Miku Yasukawa, Erina Asano, Ryuji Kasamatsu, Mai Ueda, Shigeru Yoshida, Atsufumi Kawabata, BIOCHEMICAL PHARMACOLOGY, BIOCHEMICAL PHARMACOLOGY, 97(3), 300 - 309, Oct. 2015 , Refereed
    Summary:Neuroendocrine-differentiated prostate cancer cells may contribute to androgen-independent proliferation of surrounding cells through Ca2+-dependent secretion of mitogenic factors. Human prostate cancer LNCaP cells, when neuroendocrine-differentiated, overexpress Ca(v)3.2 T-type Ca2+ channels that contribute to Ca2+-dependent secretion. Given evidence for the acceleration of Ca(v)3.2 activity by hydrogen sulfide (H2S), we examined the roles of the H2S/Ca(v)3.2 pathway and then analyzed the molecular mechanisms of the Ca(v)3.2 overexpression in neuroendocrine-differentiated LNCaP cells. LNCaP cells were differentiated by dibutyryl cyclic AMP. Protein levels and T-type Ca2+ channeldependent currents (T-currents) were measured by immunoblotting and whole-cell pacth-clamp technique, respectively. Spontaneous release of prostatic acid phosphatase (PAP) was monitored to evaluate secretory function. The differentiated LNCaP cells exhibited neurite outgrowth, androgenindependent proliferation and upregulation of mitogenic factors, and also showed elevation of Ca(v)3.2 expression or T-currents. Expression of cystathionine-gamma-Iyase (CSE) and cystathionine-beta-synthase (CBS), H2S-forming enzymes, and spontaneous secretion of PAP increased following the differentiation. The augmented T-currents were enhanced by H2S donors and suppressed by inhibitors of CSE, but not CBS. The PAP secretion was reduced by inhibition of CSE or T-type Ca2+ channels. During differentiation, Egr-1 and REST, positive and negative transcriptional regulators for Ca(v)3.2, were upregulated and downregulated, respectively, and Egr-1 knockdown prevented the Ca(v)3.2 overexpression. Our data suggest that, in neuroendocrine-differentiated LNCaP cells, H2S formed by the upregulated CSE promotes the activity of the upregulated Ca(v)3.2, leading to the elevated secretory functions. The overexpression of Ca(v)3.2 appears to involve upregulation of Egr-1 and downregulation of REST. (C) 2015 Elsevier Inc. All rights reserved.
  • Roles of Ca(v)3.2 and TRPA1 Channels Targeted by Hydrogen Sulfide in Pancreatic Nociceptive Processing in Mice With or Without Acute Pancreatitis, Yuka Terada, Mayuko Fujimura, Sachiyo Nishimura, Maho Tsubota, Fumiko Sekiguchi, Atsufumi Kawabata, JOURNAL OF NEUROSCIENCE RESEARCH, JOURNAL OF NEUROSCIENCE RESEARCH, 93(2), 361 - 369, Feb. 2015 , Refereed
    Summary:Hydrogen sulfide (H2S), formed by multiple enzymes, including cystathionine--lyase (CSE), targets Ca(v)3.2 T-type Ca2+ channels (T channels) and transient receptor potential ankyrin-1 (TRPA1), facilitating somatic pain. Pancreatitis-related pain also appears to involve activation of T channels by H2S formed by the upregulated CSE. Therefore, this study investigates the roles of the Ca(v)3.2 isoform and/or TRPA1 in pancreatic nociception in the absence and presence of pancreatitis. In anesthetized mice, AP18, a TRPA1 inhibitor, abolished the Fos expression in the spinal dorsal horn caused by injection of a TRPA1 agonist into the pancreatic duct. As did mibefradil, a T-channel inhibitor, in our previous report, AP18 prevented the Fos expression following ductal NaHS, an H2S donor. In the mice with cerulein-induced acute pancreatitis, the referred hyperalgesia was suppressed by NNC 55-0396 (NNC), a selective T-channel inhibitor; zinc chloride; or ascorbic acid, known to inhibit Ca(v)3.2 selectively among three T-channel isoforms; and knockdown of Ca(v)3.2. In contrast, AP18 and knockdown of TRPA1 had no significant effect on the cerulein-induced referred hyperalgesia, although they significantly potentiated the antihyperalgesic effect of NNC at a subeffective dose. TRPA1 but not Ca(v)3.2 in the dorsal root ganglia was downregulated at a protein level in mice with cerulein-induced pancreatitis. The data indicate that TRPA1 and Ca(v)3.2 mediate the exogenous H2S-induced pancreatic nociception in naive mice and suggest that, in the mice with pancreatitis, Ca(v)3.2 targeted by H2S primarily participates in the pancreatic pain, whereas TRPA1 is downregulated and plays a secondary role in pancreatic nociceptive signaling. (c) 2014 Wiley Periodicals, Inc.
  • Polaprezinc attenuates cyclophosphamide-induced cystitis and related bladder pain in mice, Masahiro Murakami-Nakayama, Maho Tsubota, Saki Hiruma, Fumiko Sekiguchi, Kenji Matsuyama, Takeshi Kimura, Masahiro Moriyama, Atsufumi Kawabata, JOURNAL OF PHARMACOLOGICAL SCIENCES, JOURNAL OF PHARMACOLOGICAL SCIENCES, 127(2), 223 - 228, Feb. 2015 , Refereed
    Summary:Ca(v)3.2 T-type Ca2+ channels targeted by H2S, a gasotransmitter, participate in cyclophosphamide-induced cystitis and bladder pain. Given that zinc selectively inhibits Ca(v)3.2 among T-channel isoforms and also exhibits antioxidant activity, we examined whether polaprezinc (zinc-L-carnosine), a medicine for peptic ulcer treatment and zinc supplementation, reveals preventive or therapeutic effects on bladder inflammation and/or pain in the mouse with cyclophosphamide-induced cystitis, a model for interstitial cystitis. Systemic administration of cyclophosphamide caused cystitis-related symptoms including increased bladder weight and vascular permeability, and histological signs of bladder edema, accompanied by bladder pain-like nociceptive behavior/referred hyperalgesia. All these symptoms were significantly attenuated by oral preadministration of polaprezinc at 400 mg/kg. The same dose of polaprezinc also prevented the increased malondialdehyde level, an indicator of lipid peroxidation, and protein upregulation of cystathionine-gamma-Iyase. an H2S-generating enzyme, but not occludin, a tight junction-related membrane protein, in the bladder tissue of cyclophosphamide-treated mice. Oral posttreatment with polaprezinc at 30-100 mg/kg reversed the nociceptive behavior/referred hyperalgesia in a dose-dependent manner without affecting the increased bladder weight. Together, our data show that zinc supplementation with polaprezinc prevents the cyclophosphamide-induced cystitis probably through the antioxidant activity, and, like T-channel blockers, reverses the established cystitis-related bladder pain in mice, suggesting novel therapeutic usefulness of polaprezinc. (C) 2015 Japanese Pharmacological Society. Production and hosting by Elsevier B.V. All rights reserved.
  • Mechanisms for proteinase-activated receptor 1-triggered prostaglandin E-2 generation in mouse osteoblastic MC3T3-E1 cells, Yuma Maeda, Fumiko Sekiguchi, Rumi Yamanaka, Ryo Sugimoto, Daichi Yamasoba, Shiori Tomita, Hiroyuki Nishikawa, Atsufumi Kawabata, BIOLOGICAL CHEMISTRY, BIOLOGICAL CHEMISTRY, 396(2), 153 - 162, Feb. 2015 , Refereed
    Summary:We analyzed signaling mechanisms for prostaglandin E-2 (PGE(2)) production following activation of proteinase-activated receptor-1 (PAR1), a thrombin receptor, in preosteoblastic MC3T3-E1 cells. PAR1 stimulation caused PGE(2) release, an effect suppressed by inhibitors ;of COX-1, COX-2, iPLA(2), cPLA(2), MAP kinases (MAPKs), Src, EGF receptor (EGFR) tyrosine kinase (EGFR-TK) and matrix metalloproteinase (MMP), but not by an intracellular Ca2+ chelator or inhibitors of PI3 kinase, protein kinase C (PKC) and NF-kappa B. PAR1 activation induced phosphorylation of MAPKs and upregulation of COX-2. The phosphorylation of p38 MAPK was suppressed by inhibitors of Src and EGFR-TK. The COX-2 upregulation was dependent on ERK, p38, EGFR-TK, Src, and COX-2 itself. PAR1 activation also induced MEK-dependent phosphorylation of cAMP response element binding protein (CREB). All inhibitors of EP1, EP2, EP3 and EP4 receptors suppressed the PAR1-triggered PGE(2) release. Exogenously applied PGE(2) facilitated PAR1-triggered COX-2 upregulation, but it alone had no effect. Together, the PAR1-mediated PGE(2) production in MC3T3-E1 cells appears to involve iPLA(2) and cPLA(2) for arachidonic acid release, and the MEK/ERK/CREB and Src/MMP/EGFR/p38 pathways for COX-2 upregulation, which is facilitated by endogenous PGE(2) formed by COX-2. These signaling mechanisms might underlie the role of the thrombin/PAR1/PGE(2) system in the early stage of the bone healing.
  • Bladder pain relief by HMGB1 neutralization and soluble thrombomodulin in mice with cyclophosphamide-induced cystitis, Junichi Tanaka, Kaoru Yamaguchi, Hiroyasu Ishikura, Maho Tsubota, Fumiko Sekiguchi, Yukari Seki, Toshifumi Tsujiuchi, Akira Murai, Takehiro Umemura, Atsufumi Kawabata, NEUROPHARMACOLOGY, NEUROPHARMACOLOGY, 79, 112 - 118, Apr. 2014 , Refereed
    Summary:High mobility group box 1 (HMGB1), one of damage-associated molecular patterns (DAMPs), plays roles in not only inflammation but also processing of somatic pain. Given that no evidence for roles of HMGB1 in visceral pain signaling is available, we asked if HMGB1 participates in bladder pain accompanying cystitis caused by cyclophosphamide in mice, using the anti-HMGB1 neutralizing antibody and recombinant human soluble thrombomodulin (rhsTM) that sequesters HMGB1 and promotes its degradation by thrombin. Cyclophosphamide, administered i.p., caused bladder pain-like nociceptive behavior and referred hyperalgesia accompanying cystitis symptoms including increased bladder weight, an indicator of edema, in mice. The cyclophosphamide-induced bladder pain and referred hyperalgesia, but not increased bladder weight, were prevented by i.p. preadministration of the anti-HMGB1 neutralizing antibody or rhsTM. HMGB1, given i.p., facilitated the bladder pain and referred hyperalgesia caused by a subeffective dose of cyclophosphamide, an effect blocked by rhsTM. In the cyclophosphamide-treated mice, HMGB1 levels greatly decreased in the bladder tissue, particularly in the urothelial cells, but did not change in the plasma. Low molecular weight heparin, known to inhibit the receptor for advanced glycation end products (RAGE), but not lipopolysaccharide from Rhodobacter sphaeroides, an inhibitor of toll-like receptor 4 (TLR4), blocked the cyclophosphamide-induced bladder pain and referred hyperalgesia. Thus, our data indicate involvement of HMGB1 in the cyclophosphamide-induced bladder pain signaling, but not cystitis itself, and suggest that targeting HMGB1 with rhsTM or blocking RAGE might serve as a novel therapeutic strategy for the management of bladder pain. (C) 2013 Elsevier Ltd. All rights reserved.
  • Endogenous and exogenous hydrogen sulfide facilitates T-type calcium channel currents in Ca(v)3.2-expressing HEK293 cells, Fumiko Sekiguchi, Yosuke Miyamoto, Daiki Kanaoka, Hiroki Ide, Shigeru Yoshida, Tsuyako Ohkubo, Atsufumi Kawabata, BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 445(1), 225 - 229, Feb. 2014 , Refereed
    Summary:Hydrogen sulfide (H2S), a gasotransmitter, is formed from L-cysteine by multiple enzymes including cystathionine-gamma-lyase (CSE). We have shown that an H2S donor, NaHS, causes hyperalgesia in rodents, an effect inhibited by knockdown of Ca(v)3.2 T-type Ca2+ channels (T-channels), and that NaHS facilitates T-channel-dependent currents (T-currents) in NG108-15 cells that naturally express Ca(v)3.2. In the present study, we asked if endogenous and exogenous H2S participates in regulation of the channel functions in Ca(v)3.2-transfected HEK293 (Ca(v)3.2-HEK293) cells. DL-Propargylglycine (PPG), a CSE inhibitor, significantly decreased T-currents in Ca(v)3.2-HEK293 cells, but not in NG108-15 cells. NaHS at 1.5 mM did not affect T-currents in Ca(v)3.2-HEK293 cells, but enhanced T-currents in NG108-15 cells. In the presence of PPG, NaHS at 1.5 mM, but not 0.1-0.3 mM, increased T-currents in Ca(v)3.2-HEK293 cells. Similarly, Na2S, another H2S donor, at 0.1-0.3 mM significantly increased T-currents in the presence, but not absence, of PPG in Ca(v)3.2-HEK293 cells. Expression of CSE was detected at protein and mRNA levels in HEK293 cells. Intraplantar administration of Na2S, like NaHS, caused mechanical hyperalgesia, an effect blocked by NNC 55-0396, a T-channel inhibitor. The in vivo potency of Na2S was higher than NaHS. These results suggest that the function of Ca(v)3.2 T-channels is tonically enhanced by endogenous H2S synthesized by CSE in Ca(v)3.2-HEK293 cells, and that exogenous H2S is capable of enhancing Ca(v)3.2 function when endogenous H2S production by CSE is inhibited. In addition, Na2S is considered a more potent H2S donor than NaHS in vitro as well as in vivo. (C) 2014 Elsevier Inc. All rights reserved.
  • Contribution of TRPA1 as a Downstream Signal of Proteinase-Activated Receptor-2 to Pancreatic Pain, Yuka Terada, Mayuko Fujimura, Sachiyo Nishimura, Maho Tsubota, Fumiko Sekiguchi, Hiroyuki Nishikawa, Atsufumi Kawabata, JOURNAL OF PHARMACOLOGICAL SCIENCES, JOURNAL OF PHARMACOLOGICAL SCIENCES, 123(3), 284 - 287, Nov. 2013 , Refereed
    Summary:We examined if TRPA1, like TRPV1, contributes to pancreatic nociceptor excitation following proteinase-activated receptor-2 (PAR2) stimulation and to pancreatitis-related pain in mice. A PAR2-activating peptide, infused into the pancreatic duct, caused spinal Fos expression, which was prevented by AP18, a TRPA1 inhibitor. Repeated administration of cerulein caused referred hyperalgesia accompanying pancreatitis, which was reversed by SB366791, a TRPV1 inhibitor, but not AP18. AP18, administered in combination with a subeffective dose of SB366791, significantly suppressed the referred hyperalgesia. Our findings suggest that TRPA1, like TRPV1, mediates PAR2-triggered pancreatic nociception and that TRPA1 in collaboration with TRPV1 latently contributes to pancreatitis-related pain.
  • T-type Calcium Channels: Functional Regulation and Implication in Pain Signaling, Fumiko Sekiguchi, Atsufumi Kawabata, JOURNAL OF PHARMACOLOGICAL SCIENCES, JOURNAL OF PHARMACOLOGICAL SCIENCES, 122(4), 244 - 250, Aug. 2013 , Refereed
    Summary:Low-voltage-activated T-type Ca2+ channels (T-channels), especially Ca(v)3.2 among the three isoforms (Ca(v)3.1, Ca(v)3.2, and Ca(v)3.3), are now considered to play pivotal roles in processing of pain signals. Ca(v)3.2 T-channels are functionally modulated by extracellular substances such as hydrogen sulfide and ascorbic acid, by intracellular signaling molecules including protein kinases, and by glycosylation. Ca(v)3.2 T-channels are abundantly expressed in both peripheral and central endings of the primary afferent neurons, regulating neuronal excitability and release of excitatory neurotransmitters such as substance P and glutamate, respectively. Functional upregulation of Ca(v)3.2 T-channels is involved in the pathophysiology of inflammatory, neuropathic, and visceral pain. Thus, Ca(v)3.2 T-channels are considered to serve as novel targets for development of drugs for treatment of intractable pain resistant to currently available analgesics.
  • AKAP-dependent sensitization of Cav3.2 channels via the EP4 receptor/cAMP pathway mediates PGE2-induced mechanical hyperalgesia, Fumiko Sekiguchi, Yuka Aoki, Maiko Nakagawa, Daiki Kanaoka, Yuta Nishimoto, Maho Tsubota-Matsunami, Rumi Yamanaka, Shigeru Yoshida, Atsufumi Kawabata, BRITISH JOURNAL OF PHARMACOLOGY, BRITISH JOURNAL OF PHARMACOLOGY, 168(3), 734 - 745, Feb. 2013
    Summary:Background and Purpose The Cav3.2 isoform of T-type Ca2+ channels (T channels) is sensitized by hydrogen sulfide, a pro-nociceptive gasotransmitter, and also by PKA that mediates PGE2-induced hyperalgesia. Here we examined and analysed Cav3.2 sensitization via the PGE2/cAMP pathway in NG108-15 cells that express Cav3.2 and produce cAMP in response to PGE2, and its impact on mechanical nociceptive processing in rats. Experimental Approach In NG108-15 cells and rat dorsal root ganglion (DRG) neurons, T-channel-dependent currents (T currents) were measured with the whole-cell patch-clamp technique. The molecular interaction of Cav3.2 with A-kinase anchoring protein 150 (AKAP150) and its phosphorylation were analysed by immunoprecipitation/immunoblotting in NG108-15 cells. Mechanical nociceptive threshold was determined by the paw pressure test in rats. Key Results In NG108-15 cells and/or rat DRG neurons, dibutyryl cAMP (db-cAMP) or PGE2 increased T currents, an effect blocked by AKAP St-Ht31 inhibitor peptide (AKAPI) or KT5720, a PKA inhibitor. The effect of PGE2 was abolished by RQ-00015986-00, an EP4 receptor antagonist. AKAP150 was co-immunoprecipitated with Cav3.2, regardless of stimulation with db-cAMP, and Cav3.2 was phosphorylated by db-cAMP or PGE2. In rats, intraplantar (i.pl.) administration of db-cAMP or PGE2 caused mechanical hyperalgesia, an effect suppressed by AKAPI, two distinct T-channel blockers, NNC 55-0396 and ethosuximide, or ZnCl2, known to inhibit Cav3.2 among T channels. Oral administration of RQ-00015986-00 suppressed the PGE2-induced mechanical hyperalgesia. Conclusion and Implications Our findings suggest that PGE2 causes AKAP-dependent phosphorylation and sensitization of Cav3.2 through the EP4 receptor/cAMP/PKA pathway, leading to mechanical hyperalgesia in rats.
  • AKAP-dependent sensitization of Cav3.2 channels via the EP4 receptor/cAMP pathway mediates PGE2-induced mechanical hyperalgesia, Fumiko Sekiguchi, Yuka Aoki, Maiko Nakagawa, Daiki Kanaoka, Yuta Nishimoto, Maho Tsubota-Matsunami, Rumi Yamanaka, Shigeru Yoshida, Atsufumi Kawabata, BRITISH JOURNAL OF PHARMACOLOGY, BRITISH JOURNAL OF PHARMACOLOGY, 168(3), 734 - 745, Feb. 2013 , Refereed
    Summary:Background and Purpose The Cav3.2 isoform of T-type Ca2+ channels (T channels) is sensitized by hydrogen sulfide, a pro-nociceptive gasotransmitter, and also by PKA that mediates PGE2-induced hyperalgesia. Here we examined and analysed Cav3.2 sensitization via the PGE2/cAMP pathway in NG108-15 cells that express Cav3.2 and produce cAMP in response to PGE2, and its impact on mechanical nociceptive processing in rats. Experimental Approach In NG108-15 cells and rat dorsal root ganglion (DRG) neurons, T-channel-dependent currents (T currents) were measured with the whole-cell patch-clamp technique. The molecular interaction of Cav3.2 with A-kinase anchoring protein 150 (AKAP150) and its phosphorylation were analysed by immunoprecipitation/immunoblotting in NG108-15 cells. Mechanical nociceptive threshold was determined by the paw pressure test in rats. Key Results In NG108-15 cells and/or rat DRG neurons, dibutyryl cAMP (db-cAMP) or PGE2 increased T currents, an effect blocked by AKAP St-Ht31 inhibitor peptide (AKAPI) or KT5720, a PKA inhibitor. The effect of PGE2 was abolished by RQ-00015986-00, an EP4 receptor antagonist. AKAP150 was co-immunoprecipitated with Cav3.2, regardless of stimulation with db-cAMP, and Cav3.2 was phosphorylated by db-cAMP or PGE2. In rats, intraplantar (i.pl.) administration of db-cAMP or PGE2 caused mechanical hyperalgesia, an effect suppressed by AKAPI, two distinct T-channel blockers, NNC 55-0396 and ethosuximide, or ZnCl2, known to inhibit Cav3.2 among T channels. Oral administration of RQ-00015986-00 suppressed the PGE2-induced mechanical hyperalgesia. Conclusion and Implications Our findings suggest that PGE2 causes AKAP-dependent phosphorylation and sensitization of Cav3.2 through the EP4 receptor/cAMP/PKA pathway, leading to mechanical hyperalgesia in rats.
  • Involvement of the endogenous hydrogen sulfide/Cav3.2 T-type Ca2+channel pathway in cystitis-related bladder pain in mice, Maho Matsunami, Takahiro Miki, Kanae Nishiura, Yuko Hayashi, Yasumasa Okawa, Hiroyuki Nishikawa, Fumiko Sekiguchi, Lisa Kubo, Tomoka Ozaki, Toshifumi Tsujiuchi, Atsufumi Kawabata, BRITISH JOURNAL OF PHARMACOLOGY, BRITISH JOURNAL OF PHARMACOLOGY, 167(4), 917 - 928, Oct. 2012 , Refereed
    Summary:BACKGROUND AND PURPOSE Hydrogen sulfide (H2S), generated by enzymes such as cystathionine-?-lyase (CSE) from L-cysteine, facilitates pain signals by activating the Cav3.2 T-type Ca2+ channels. Here, we assessed the involvement of the CSE/H2S/Cav3.2 pathway in cystitis-related bladder pain. EXPERIMENTAL APPROACH Cystitis was induced by i.p. administration of cyclophosphamide in mice. Bladder pain-like nociceptive behaviour was observed and referred hyperalgesia was evaluated using von Frey filaments. Phosphorylation of ERK in the spinal dorsal horn was determined immunohistochemically following intravesical administration of NaHS, an H2S donor. KEY RESULTS Cyclophosphamide caused cystitis-related symptoms including increased bladder weight, accompanied by nociceptive changes (bladder pain-like nociceptive behaviour and referred hyperalgesia). Pretreatment with DL-propargylglycine, an inhibitor of CSE, abolished the nociceptive changes and partly prevented the increased bladder weight. CSE protein in the bladder was markedly up-regulated during development of cystitis. Mibefradil or NNC 550396, blockers of T-type Ca2+ channels, administered after the symptoms of cystitis appeared, reversed the nociceptive changes. Further, silencing of Cav3.2 protein by repeated intrathecal administration of mouse Cav3.2-targeting antisense oligodeoxynucleotides also significantly attenuated the nociceptive changes, but not the increased bladder weight. Finally, the number of cells staining positive for phospho-ERK was increased in the superficial layer of the L6 spinal cord after intravesical administration of NaHS, an effect inhibited by NNC 550396. CONCLUSION AND IMPLICATIONS Endogenous H2S, generated by up-regulated CSE, caused bladder pain and referred hyperalgesia through the activation of Cav3.2 channels, one of the T-type Ca2+ channels, in mice with cyclophosphamide-induced cystitis.
  • Hydrogen sulfide-induced mechanical hyperalgesia and allodynia require activation of both Cav3.2 and TRPA1 channels in mice, Kazumasa Okubo, Midori Matsumura, Yudai Kawaishi, Yuka Aoki, Maho Matsunami, Yasumasa Okawa, Fumiko Sekiguchi, Atsufumi Kawabata, BRITISH JOURNAL OF PHARMACOLOGY, BRITISH JOURNAL OF PHARMACOLOGY, 166(5), 1738 - 1743, Jul. 2012 , Refereed
    Summary:BACKGROUND AND PURPOSE Hydrogen sulfide, a gasotransmitter, facilitates somatic pain signals via activation of Cav3.2 T-type calcium channels in rats. Given evidence for the activation of transient receptor potential ankyrin-1 (TRPA1) channels by H2S, we asked whether TRPA1 channels, in addition to Cav3.2 channels, contribute to the H2S-induced mechanical hyperalgesia and allodynia in mice. EXPERIMENTAL APPROACH Mechanical hyperalgesia and allodynia were evaluated by the von Frey test in mice. Cav3.2 or TRPA1 channels in the sensory neurons were silenced by repeated intrathecal administration of antisense oligodeoxynucleotides in mice. KEY RESULTS Intraplantar administration of NaHS evoked hyperalgesia and allodynia in mice, an effect attenuated or abolished by NNC 550396 or mibefradil, T-type calcium channel blockers, and by ascorbic acid or zinc chloride, known to selectively inhibit Cav3.2 channels, out of the three isoforms of T-type calcium channels. Silencing of Cav3.2 channels in the sensory neurons also prevented the NaHS-induced hyperalgesia and allodynia in mice. The NaHS-induced hyperalgesia and allodynia in mice were significantly suppressed by AP18, a TRPA1 channel blocker, and by silencing of TRPA1 channels in the sensory neurons. CONCLUSIONS AND IMPLICATIONS Mechanical hyperalgesia and allodynia induced by NaHS/H2S required activation of both Cav3.2 and TRPA1 channels in mice.
  • Colonic Hydrogen Sulfide-Induced Visceral Pain and Referred Hyperalgesia Involve Activation of Both Ca(v)3.2 and TRPA1 Channels in Mice, Maho Tsubota-Matsunami, Yumi Noguchi, Yasumasa Okawa, Fumiko Sekiguchi, Atsufumi Kawabata, JOURNAL OF PHARMACOLOGICAL SCIENCES, JOURNAL OF PHARMACOLOGICAL SCIENCES, 119(3), 293 - 296, Jul. 2012 , Refereed
    Summary:Luminal hydrogen sulfide (H2S), a gasotransmitter, causes colonic pain / referred hyperalgesia in mice, most probably via activation of T-type Ca2+ channels. Here we analyzed the mechanisms for H2S-induced facilitation of colonic pain signals. Intracolonic administration of NaHS, an H2S donor, evoked visceral pain-like nociceptive behavior and referred hyperalgesia in mice, an effect abolished by NNC 55-0396, a selective T-type Ca2+-channel blocker, or by knockdown of Ca(v)3.2. AP18, a TRPA1 blocker, also prevented the NaHS-induced colonic pain and referred hyperalgesia. These findings demonstrate that H2S-induced colonic pain and referred hyperalgesia require activation of both Ca(v)3.2 and TRPA1 channels in mice.
  • Involvement of ERK in NMDA receptor-independent cortical neurotoxicity of hydrogen sulfide, Yuko Kurokawa, Fumiko Sekiguchi, Satoko Kubo, Yoshiko Yamasaki, Sachi Matsuda, Yukari Okamoto, Teruki Sekimoto, Anna Fukatsu, Hiroyuki Nishikawa, Toshiaki Kume, Nobuyuki Fukushima, Akinori Akaike, Atsufumi Kawabata, BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 414(4), 727 - 732, Nov. 2011 , Refereed
    Summary:Hydrogen sulfide (H(2)S), a gasotransmitter, exerts both neurotoxicity and neuroprotection, and targets multiple molecules including NMDA receptors, T-type calcium channels and NO synthase (NOS) that might affect neuronal viability. Here, we determined and characterized effects of NaHS, an H(2)S donor, on cell viability in the primary cultures of mouse fetal cortical neurons. NaHS caused neuronal death, as assessed by LDH release and trypan blue staining, but did not significantly reduce the glutamate toxicity. The neurotoxicity of NaHS was resistant to inhibitors of NMDA receptors, T-type calcium channels and NOS, and was blocked by inhibitors of MEK, but not JNK, p38 MAP kinase, PKC and Src. NaHS caused prompt phosphorylation of ERK and upregulation of Bad, followed by translocation of Bax to mitochondria and release of mitochondrial cytochrome c(1) leading to the nuclear condensation/fragmentation. These effects of NaHS were suppressed by the MEK inhibitor. Our data suggest that the NMDA receptor-independent neurotoxicity of H(2)S involves activation of the MEK/ERK pathway and some apoptotic mechanisms. (C) 2011 Elsevier Inc. All rights reserved.
  • INHIBITION OF T-TYPE CALCIUM CHANNELS AND HYDROGEN SULFIDE-FORMING ENZYME REVERSES PACLITAXEL-EVOKED NEUROPATHIC HYPERALGESIA IN RATS, K. Okubo, T. Takahashi, F. Sekiguchi, D. Kanaoka, M. Matsunami, T. Ohkubo, J. Yamazaki, N. Fukushima, S. Yoshida, A. Kawabata, NEUROSCIENCE, NEUROSCIENCE, 188, 148 - 156, Aug. 2011 , Refereed
    Summary:Hydrogen sulfide (H,S), a gasotransmitter, facilitates pain sensation by targeting Ca(v)3.2 T-type calcium channels. The H(2)S/Ca(v)3.2 pathway appears to play a role in the maintenance of surgically evoked neuropathic pain. Given evidence that chemotherapy-induced neuropathic pain is blocked by ethosuximide, known to block T-type calcium channels, we examined if more selective T-type calcium channel blockers and also inhibitors of cystathionine-gamma-lyase (CSE), a major H(2)S-forming enzyme in the peripheral tissue, are capable of reversing the neuropathic pain evoked by paclitaxel, an anti-cancer drug. It was first demonstrated that T-type calcium channel blockers, NNC 55-0396, known to inhibit Ca(v)3.1, and mibefradil inhibited T-type currents in Ca(v)3.2-transfected HEK293 cells. Repeated systemic administration of paclitaxel caused delayed development of mechanical hyperalgesia, which was reversed by single intraplantar administration of NNC 550396 or mibefradil, and by silencing of Ca(v)3.2 by antisense oligodeoxynucleotides. Systemic administration of DL-propargylglycine and p-cyanoalanine, irreversible and reversible inhibitors of CSE, respectively, also abolished the established neuropathic hyperalgesia. In the paclitaxel-treated rats, upregulation of Ca(v)3.2 and CSE at protein levels was not detected in the dorsal root ganglia (DRG), spinal cord or peripheral tissues including the hindpaws, whereas H(2)S content in hindpaw tissues was significantly elevated. Together, our study demonstrates the effectiveness of NNC 55-0396 in inhibiting Ca(v)3.2, and then suggests that paclitaxel-evoked neuropathic pain might involve the enhanced activity of T-type calcium channels and/or CSE in rats, but not upregulation of Ca(v)3.2 and CSE at protein levels, differing from the previous evidence for the neuropathic pain model induced by spinal nerve cutting in which Ca(v)3.2 was dramatically upregulated in DRG. (C) 2011 IBRO. Published by Elsevier Ltd. All rights reserved.
  • Delayed Production of Arachidonic Acid Contributes to the Delay of Proteinase-Activated Receptor-1 (PAR1)-Triggered Prostaglandin E-2 Release in Rat Gastric Epithelial RGM1 Cells, Fumiko Sekiguchi, Ai Ohi, Yuma Maeda, Kaori Takaoka, Teruki Sekimoto, Hiroyuki Nishikawa, Atsufumi Kawabata, JOURNAL OF CELLULAR BIOCHEMISTRY, JOURNAL OF CELLULAR BIOCHEMISTRY, 112(3), 909 - 915, Mar. 2011 , Refereed
    Summary:Proteinase-activated receptor-1 (PAR I), upon activation, exerts prostanoid-dependent gastroprotection, and increases prostaglandin E-2 (PGE(2)) release through cyclooxygenase-2 (COX-2) upregulation in rat gastric mucosal epithelial RGM1 cells. However, there is a big time lag between the PAR I-triggered PG E2 release and COX-2 upregulation in RGM1 cells; that is, the former event takes 18 h to occur, while the latter rapidly develops and reaches a plateau in 6 h. The present study thus aimed at clarifying mechanisms for the delay of PGE2 release after PAR activation in RGM1 cells. Although a PAR1-activating peptide, TFLLR-NH2, alone caused PGE2 release at 18 h, but not 6 h, TFLLR-NH2 in combination with arachidonic acid dramatically enhanced PGE(2) release even for 1-6 h. TFLLR-NH2 plus linoleic acid caused a similar rapid response. CP-24879, a Delta(5)/Delta(6)-desaturase inhibitor, abolished the PGE(2) release induced by TFLLR-NH2 plus linoleic acid, but not by TFLLR-NH2 alone. The TFLLR-NH2-induced PGE2 release was not affected by inhibitors of cytosolic phospholipase A(2) (cPLA(2)), Ca2+-independent PLA(2) (cPLA2) or secretory PLA(2) (sPLA(2)), but was abolished by their mixture or a pan-PLA(2) inhibitor. Among PLA2 isozymes, mRNA of group IIA sPLA(2) (sPLA(2)-IIA) was upregulated following PAR1 stimulation for 6-18 h, whereas protein levels of PGE synthases were unchanged. These data suggest that the delay of PG E2 release after COX-2 upregulation triggered by PAR1 is due to the poor supply of free arachidonic acid at the early stage in RGM1 cells, and that plural isozymes of PLA2 including sPLA2-IIA may complementarily contribute to the liberation of free arachidonic acid. J. Cell. Biochem. 112: 909-915,2011. (C) 2010 Wiley-Liss, Inc.
  • The proteinase/proteinase-activated receptor-2/transient receptor potential vanilloid-1 cascade impacts pancreatic pain in mice, Sachiyo Nishimura, Hiroyasu Ishikura, Maho Matsunami, Yui Shinozaki, Fumiko Sekiguchi, Mitsuhide Naruse, Taisuke Kitamura, Ryukichi Akashi, Kenji Matsumura, Atsufumi Kawabata, LIFE SCIENCES, LIFE SCIENCES, 87(19-22), 643 - 650, Nov. 2010 , Refereed
    Summary:Aims: Proteinase-activated receptor-2 (PAR2) and transient receptor potential vanilloid-1 (TRPV1) are co-localized in the primary afferents, and the trans-activation of TRPV1 by PAR2 activation is involved in processing of somatic pain. Given evidence for contribution of PAR2 to pancreatic pain, the present study aimed at clarifying the involvement of TRPV1 in processing of pancreatic pain by the proteinase/PAR2 pathway in mice. Main methods: Acute pancreatitis was created by repeated administration of cerulein in conscious mice, and the referred allodynia/hyperalgesia was assessed using von Frey filaments. Injection of PAR2 agonises into the pancreatic duct was achieved in anesthetized mice, and expression of Fos in the spinal cord was determined by immunohistochemistry. Key findings: The established referred allodynia/hyperalgesia following cerulein treatment was abolished by post-treatment with nafamostat mesilate, a proteinase inhibitor, and with capsazepine, a TRPV1 antagonist, in mice. Injection of trypsin, an endogenous PAR2 agonist, or SLIGRL-NH(2), a PAR2-activating peptide, into the pancreatic duct caused expression of Fos protein in the spinal superficial layers at T8-T10 levels in the mice. The spinal Fos expression caused by trypsin and by SLIGRL-NH(2) was partially blocked by capsazepine, the former effect abolished by nafamostat mesilate. Significance: Our data thus suggest that the proteinase/PAR2/TRPV1 cascade might impact pancreatic pain, in addition to somatic pain, and play a role in the maintenance of pancreatitis-related pain in mice. (C) 2010 Elsevier Inc. All rights reserved.
  • Involvement of Src kinase in T-type calcium channel-dependent neuronal differentiation of NG108-15 cells by hydrogen sulfide, Takeshi Tarui, Kazuki Fukami, Keita Nagasawa, Shigeru Yoshida, Fumiko Sekiguchi, Atsufumi Kawabata, JOURNAL OF NEUROCHEMISTRY, JOURNAL OF NEUROCHEMISTRY, 114(2), 512 - 519, Jul. 2010 , Refereed
    Summary:P>Hydrogen sulfide (H(2)S), a gasotransmitter, induces neuronal differentiation characterized by neuritogenesis and functional up-regulation of high voltage-activated Ca2+ channels, via activation of T-type Ca2+ channels in NG108-15 cells. We thus analyzed signaling mechanisms for the H(2)S-evoked neuronal differentiation. NaHS, a donor for H(2)S, facilitated T-type Ca2+ channel-dependent membrane currents, an effect blocked by ascorbic acid that selectively inhibits Ca(v)3.2 among three T-type channel isoforms. NaHS, applied once at a high concentration (13.5 mM) or repetitively at a relatively low concentration (1.5 mM), as well as ionomycin, a Ca2+ ionophore, evoked neuritogenesis. The neuritogenesis induced by NaHS, but not by ionomycin, was abolished by mibefradil, a T-type Ca2+ channel blocker. PP2, a Src kinase inhibitor, completely suppressed the neuritogenesis caused by NaHS or ionomycin, while it only partially blocked neuritogenesis caused by dibutyryl cAMP, a differentiation inducer. NaHS, but not dibutyryl cAMP, actually caused phosphorylation of Src, an effect blocked by 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl, an intracellular Ca2+ chelator, mibefradil or ascorbic acid. The up-regulation of high voltage-activated currents in the cells treated with NaHS was also inhibited by PP2. Together, our data reveal that Src kinase participates in the T-type Ca2+ channel-dependent neuronal differentiation caused by NaHS/H(2)S in NG108-15 cells.
  • Upregulation of Ca(v)3.2 T-type calcium channels targeted by endogenous hydrogen sulfide contributes to maintenance of neuropathic pain, Tomoko Takahashi, Yuka Aoki, Kazumasa Okubo, Yumi Maeda, Fumiko Sekiguchi, Kenji Mitani, Hiroyuki Nishikawa, Atsufumi Kawabata, PAIN, PAIN, 150(1), 183 - 191, Jul. 2010 , Refereed
    Summary:Hydrogen sulfide (H2S) formed from L-cysteine by multiple enzymes including cystathionine-gamma-lyase (CSE) is now considered a gasotransmitter in the mammalian body. Our previous studies have shown that H2S activates/sensitizes Ca(v)3.2 T-type Ca2+ channels, leading to facilitation of somatic and visceral nociception, and that CSE-derived endogenous H2S participates in inflammatory pain. Here, we show novel evidence for involvement of the endogenous H2S-Ca(v)3.2 pathway in neuropathic pain. In the rat subjected to the right L5 spinal nerve cutting (L5SNC), a neuropathic pain model, i.p. administration of DL-propargylglycine (PPG) and beta-cyanoalanine, irreversible and reversible CSE inhibitors, respectively, strongly suppressed the neuropathic hyperalgesia/allodynia. The anti-hyperalgesic effect of PPG was reversed by intraplantar administration of NaHS, a donor for H2S, in the L5SNC rat. Intraplantar administration or topical application of mibefradil, a T-type Ca2+ channel blocker, reversed hyperalgesia in the L5SNC rat. The protein levels of Ca(v)3.2, but not CSE, in the ipsilateral L4, L5 and L6 dorsal root ganglia were dramatically upregulated in the L5SNC rat. Finally, silencing of Ca(v)3.2 in DRG by repeated intrathecal administration of Ca(v)3.2-targeting siRNA significantly attenuated the neuropathic hyperalgesia in the L5SNC rat. In conclusion, our data suggest that Ca(v)3.2 T-type Ca2+ channels in sensory neurons are upregulated and activated/sensitized by CSE-derived endogenous H2S after spinal nerve injury, contributing to the maintenance of neuropathic pain. We thus propose that Ca(v)3.2 and CSE could be targets for the development of therapeutic drugs for the treatment of neuropathic pain. (C) 2010 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.
  • Opposite effects of two thiazolidinediones, ciglitazone and troglitazone, on proteinase-activated receptor-1-triggered prostaglandin E-2 release, Kaori Takaoka, Fumiko Sekiguchi, Hidenori Shigi, Yuma Maeda, Hiroyuki Nishikawa, Atsufumi Kawabata, TOXICOLOGY, TOXICOLOGY, 268(1-2), 40 - 45, Jan. 2010 , Refereed
    Summary:Thiazolidinediones, known as peroxisome proliferator-activated receptor-gamma (PPAR gamma) agonists, may modify prostaglandin formation and exert gastroprotective effects. Since activation of proteinase-activated receptor-1 (PAR1) reveals endogenous prostanoid-dependent gastroprotection, we investigated if two thiazolidinediones, ciglitazone and troglitazone, modulate the prostaglandin E-2 (PGE(2)) release caused by activation of PAR1 in normal rat gastric mucosal epithelial RGM1 cells. Ciglitazone dramatically facilitated the PAR1-triggered PGE(2) production and cyclooxygenase-2 (COX-2) upregulation, although it had no effect by itself. In contrast, troglitazone suppressed the PARI-triggered PGE2 production and COX-2 upregulation. Either effect of ciglitazone and troglitazone was resistant to GW9662, a PPAR gamma antagonist. The facilitation of the PGE(2) release by ciglitazone was blocked by inhibitors of MEK, p38 MAP kinase (p38MAPK) and PI3-kinase (PI3K), but not JNK. Nonetheless, ciglitazone failed to enhance the PAR1-triggered phosphorylation of ERK and p38MAPK. In conclusion, ciglitazone and troglitazone, exert opposite effects on the PARI-triggered PGE(2) production and COX-2 upregulation by targeting molecules other than PPAR gamma. (C) 2009 Elsevier Ireland Ltd. All rights reserved.
  • Proteinase-Activated Receptor-2-Triggered Prostaglandin E-2 Release, but Not Cyclooxygenase-2 Upregulation, Requires Activation of the Phosphatidylinositol 3-Kinase/Akt/Nuclear Factor-kappa B Pathway in Human Alveolar Epithelial Cells, Kazumi Moriyuki, Fumiko Sekiguchi, Kaori Matsubara, Hiroyuki Nishikawa, Atsufumi Kawabata, JOURNAL OF PHARMACOLOGICAL SCIENCES, JOURNAL OF PHARMACOLOGICAL SCIENCES, 111(3), 269 - 275, Nov. 2009 , Refereed
    Summary:Proteinase-activated receptor-2 (PAR2) triggers upregulation of cyclooxygenase-2 (COX-2) and prostaglandin E-2 (PGE(2)) formation in human alveolar epithelial A549 cells. This COX-2 upregulation appears to involve the Src/epidermal growth factor (EGF) receptor/p38 MAP kinase (p38MAPK) pathway and also the cAMP-response element-binding protein (CREB) pathway. Here, we investigated the roles of nuclear factor-kappa B (NF-kappa B)-related signals in the PAR2-triggered PGE(2) release/COX-2 upregulation in A549 cells. The PAR2-triggered PGE2 release was clearly blocked by an inhibitor of the NF-kappa B pathway. Stimulation of PAR2 actually caused phosphorylation of inhibitor-kappa B, an indicator of NF-kappa B activation, an effect being blocked by inhibitors of MEK, phosphatidylinositol 3-kinase (PI3-kinase), and Akt, but little or not by inhibitors of p38MAPK and JNK. Stimulation of PAR2 also caused phosphorylation of Akt, an effect suppressed by inhibitors of PI3-kinase and MEK. Nonetheless, the PAR2-triggered upregulation of COX-2 was resistant to inhibitors of NF-kappa B, PI3-kinase, and Akt, but was attenuated by inhibitors of MEK and JNK. Stimulation of PAR2 induced phosphorylation of CREB, an effect abolished by an inhibitor of MEK but not inhibitors of p38MAPK and EGF receptor. These findings demonstrate that the MEK / ERK / PI3-kinase / Akt / NF-kappa B pathway is involved in PAR2-triggered PGE2 formation, but not upregulation of COX-2 that is dependent on activation of ERK/CREB and JNK in addition to p38MAPK.
  • Hydrogen sulfide as a novel mediator for pancreatic pain in rodents, S. Nishimura, O. Fukushima, H. Ishikura, T. Takahashi, M. Matsunami, T. Tsujiuchi, F. Sekiguchi, M. Naruse, Y. Kamanaka, A. Kawabata, GUT, GUT, 58(6), 762 - 770, Jun. 2009
    Summary:Objective: Hydrogen sulfide (H(2)S) is formed from L-cysteine by multiple enzymes including cystathionine-gamma-lyase (CSE) in mammals, and plays various roles in health and disease. Recently, a pronociceptive role for H(2)S in the processing of somatic pain was identified. Here, the involvement of H(2)S in pancreatic pain is examined. Methods: Anaesthetised rats or mice received an injection of NaHS, a donor for H(2)S, or capsaicin into the pancreatic duct, and the expression of spinal Fos protein was detected by immunohistochemistry. Pancreatitis was created by 6 hourly doses of caerulein in unanaesthetised mice, and pancreatitis-related allodynia/hyperalgesia was evaluated using von Frey hairs. CSE activity and protein levels in pancreatic tissues were measured using the colorimetric method and western blotting, respectively. Results: Either NaHS or capsaicin induced the expression of Fos protein in the superficial layers of the T8 and T9 spinal dorsal horn of rats or mice. The induction of Fos by NaHS but not capsaicin was abolished by mibefradil, a T-type Ca(2+) channel blocker. In conscious mice, repeated doses of caerulein produced pancreatitis accompanied by abdominal allodynia/hyperalgesia. Pretreatment with an inhibitor of CSE prevented the allodynia/hyperalgesia, but not the pancreatitis. A single dose of mibefradil reversed the established pancreatitis-related allodynia/hyperalgesia. Either the activity or protein expression of pancreatic CSE increased after the development of caerulein-induced pancreatitis in mice. Conclusions: The data suggest that pancreatic NaHS/H(2)S most probably targets T-type Ca(2+) channels, leading to nociception, and that endogenous H(2)S produced by CSE and possibly T-type Ca(2+) channels are involved in pancreatitis-related pain.
  • Hyperalgesia induced by spinal and peripheral hydrogen sulfide: Evidence for involvement of Ca(v)3.2 T-type calcium channels, Yumi Maeda, Yuka Aoki, Fumiko Sekiguchi, Maho Matsunami, Tomoko Takahashi, Hiroyuki Nishikawa, Atsufumi Kawabata, PAIN, PAIN, 142(1-2), 127 - 132, Mar. 2009 , Refereed
    Summary:Hydrogen sulfide (H2S), a gasotransmitter, facilitates membrane currents through T-type Ca2+ channels, and intraplantar (i.pl.) administration of NaHS, a donor of H2S, causes prompt hyperalgesia in rats. In this. context, we asked whether intrathecal (i.t.) administration of NaHS could mimic the hyperalgesic effect of i.pl. NaHS in rats, and then examined if Ca(v)3.2 isoform of T-type Ca2+ channels contributed to the pronociceptive effects of i.t. and i.pl. NaHS. Either i.t. or i.pl. administration of NaHS rapidly decreased nociceptive threshold in rats, as determined by the paw pressure method. The hyperalgesia caused by i.t. and i.pl. NaHS was abolished by co-administration of mibefradil, a pan-T-type Ca2+ channel inhibitor, and also Suppressed by pretreatment with i.t. and i.pl, zinc chloride, known to preferentially inhibit Ca(v)3.2 among T-type Ca2+ channel isoforms, respectively. Repeated i.t. administration of antisense oligodeoxynucleotides (ODNs) targeting rat Cav3.2, but not mismatch ODNs, caused silencing of Ca(v)3.2 protein in the dorsal root ganglia and spinal cord, and then attenuated the hyperalgesia induced by either i.t. or i.pl, NaHS. Our findings thus establish that spinal and peripheral NaHS/H2S activates or sensitizes Ca(v)3.2 T-type Ca2+ channels expressed in the primary afferents and/or spinal nociceptive neurons, leading to sensitization of nociceptive processing and hyperalgesia. (C) 2008 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.
  • Hydrogen sulfide evokes neurite outgrowth and expression of high-voltage-activated Ca2+ currents in NG108-15 cells: involvement of T-type Ca2+ channels, Keita Nagasawa, Takeshi Tarui, Shigeru Yoshida, Fumiko Sekiguchi, Maho Matsunami, Ai Ohi, Kazuki Fukami, Seiji Ichida, Hiroyuki Nishikawa, Atsufumi Kawabata, JOURNAL OF NEUROCHEMISTRY, JOURNAL OF NEUROCHEMISTRY, 108(3), 676 - 684, Feb. 2009 , Refereed
    Summary:We investigated if stimulation of T-type Ca2+ channels with sodium hydrosulfide (NaHS), a donor of hydrogen sulfide (H2S), could cause neuronal differentiation of NG108-15 cells. Like dibutyryl cyclic AMP (db-cAMP), treatment with NaHS at 1.5-13.5 mM for 16 h enhanced neurite outgrowth in a concentration-dependent manner. Synergistic neuritogenic effect was obtained in the cells stimulated with NaHS in combination with db-cAMP at subeffective concentrations. Exposure to NaHS or db-cAMP for 2 days resulted in enhancement of expression of high-voltage-activated currents consisting of N-, P/Q-, L- and also other types, but not of T-type currents. Mibefradil, a pan-T-type channel blocker, abolished the neuritogenesis induced by NaHS, but not by db-cAMP. The NaHS-evoked neuritogenesis was also completely blocked by pretreatment with BAPTA/AM, a chelator of intracellular Ca2+, and by zinc chloride at a concentration known to selectively inhibit Ca(v)3.2 isoform of T-type Ca2+ channels, but not Ca(v)3.1 or Ca(v)3.3. Further, l-ascorbate, recently proven to selectively inhibit Ca(v)3.2, abolished the neuritogenic effect of NaHS, but not db-cAMP. Our data thus demonstrate that NaHS/H2S is a novel inducer of neuronal differentiation in NG108-15 cells, as characterized by neuritogenesis and expression of high-voltage-activated currents, and suggest the involvement of T-type Ca2+ channels, especially Ca(v)3.2.
  • PAR2 triggers IL-8 release via MEK/ERK and PI3-kinase/Akt pathways in GI epithelial cells, Yusuke Tanaka, Fumiko Sekiguchi, Hao Hong, Atsufumi Kawabata, BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 377(2), 622 - 626, Dec. 2008 , Refereed
    Summary:Proteinase-activated receptor-2 (PAR2) plays pro-inflammatory roles in many organs including the gastrointestinal (GI) tract. To clarify the downstream pro-inflammatory signaling of PAR2 in the GI tract, we examined interleukin-8 (IL-8) release and the underlying cellular signaling following PAR2 stimulation in human colorectal cancer-derived HCT-15 cells and human gastric adenocarcinoma-derived MKN-45 cells. A PAR2-activating peptide, but not a PAR2-inactive scrambled peptide or a PAR1 - activating peptide, caused IL-8 elease in these GI epithelial cells. The PAR2-triggered IL-8 release was suppressed by inhibitors of MEK (U0126) or PI3-kinase (LY294002), and PAR2 stimulation indeed activated the downstream kinases, ERK and Akt. U0126 blocked the phosphorylation of ERK, but not Akt, and LY294002 blocked the phosphorylation of Akt, but not ERK. Together, PAR2 triggers IL-8 release via two independent signaling pathways, MEK/ERK and PI3-kinase/Akt, suggesting a role of PAR2 as a pro-inflammatory receptor in the GI tract. (C) 2008 Elsevier Inc. All rights reserved.
  • Gastrointestinal roles for proteinase-activated receptors in health and disease, A. Kawabata, M. Matsunami, F. Sekiguchi, BRITISH JOURNAL OF PHARMACOLOGY, BRITISH JOURNAL OF PHARMACOLOGY, 153, S230 - S240, Mar. 2008
    Summary:It has been almost a decade since the molecular cloning of all four members of the proteinase-activated receptor ( PAR) family was completed. This unique family of G protein-coupled receptors (GPCRs) mediates specific cellular actions of various endogenous proteinases including thrombin, trypsin, tryptase, etc. and also certain exogenous enzymes. Increasing evidence has been clarifying the emerging roles played by PARs in health and disease. PARs, particularly PAR1 and PAR2, are distributed throughout the gastrointestinal (GI) tract, modulating various GI functions. One of the most important GI functions of PARs is regulation of exocrine secretion in the salivary glands, pancreas and GI mucosal epithelium. PARs also modulate motility of GI smooth muscle, involving multiple mechanisms. PAR2 appears to play dual roles in pancreatitis and related pain, being pro-inflammatory/pro-nociceptive and anti-inflammatory/anti-nociceptive. Similarly, dual roles for PAR1 and PAR2 have been demonstrated in mucosal inflammation/damage throughout the GI tract. There is also fundamental and clinical evidence for involvement of PAR2 in colonic pain. PARs are thus considered key molecules in regulation of GI functions and targets for development of drugs for treatment of various GI diseases.
  • Evidence that PAR2-triggered prostaglandin E-2 (PGE(2)) formation involves the ERK-cytosolic phospholipase A(2)-COX-1-microsomal PGE synthase-1 cascade in human lung epithelial cells, Mami Nagataki, Kazumi Moriyuki, Fumiko Sekiguchi, Atsufumi Kawabata, CELL BIOCHEMISTRY AND FUNCTION, CELL BIOCHEMISTRY AND FUNCTION, 26(2), 279 - 282, Mar. 2008 , Refereed
    Summary:We investigated possible involvement of three isozymes of prostaglandin E synthase (PGES), microsomal PGES-1 (mPGES-1), mPGES-2 and cytosolic PGES (cPGES) in COX-2-dependent prostaglandin E-2 (PGE(2)) formation following proteinase-activated receptor-2 (PAR2) stimulation in human lung epithelial cells. PAR2 stimulation up-regulated mPGES-1 as well as COX-2, but not mPGES-2 or cPGES, leading to PGE2 formation. The PAR2-triggered up-regulation of mPGES-1 was suppressed by inhibitors of COX-1, cytosolic phospholipase A(2) (cPLA(2)) and MEK, but not COX-2. Finally, a selective inhibitor of mPGES-1 strongly suppressed the PAR2-evoked PGE(2) formation. PAR2 thus appears to trigger specific up-regulation of mPGES-1 that is dependent on prostanoids formed via the MEK/ERK/cPLA(2)/COX-1 pathway, being critical for PGE(2) formation. Copyright (c) 2007 John Wiley & Sons, Ltd.
  • Gastrointestinal roles for proteinase-activated receptors in health and disease, A. Kawabata, M. Matsunami, F. Sekiguchi, BRITISH JOURNAL OF PHARMACOLOGY, BRITISH JOURNAL OF PHARMACOLOGY, 153, S230 - S240, Mar. 2008
    Summary:It has been almost a decade since the molecular cloning of all four members of the proteinase-activated receptor ( PAR) family was completed. This unique family of G protein-coupled receptors (GPCRs) mediates specific cellular actions of various endogenous proteinases including thrombin, trypsin, tryptase, etc. and also certain exogenous enzymes. Increasing evidence has been clarifying the emerging roles played by PARs in health and disease. PARs, particularly PAR1 and PAR2, are distributed throughout the gastrointestinal (GI) tract, modulating various GI functions. One of the most important GI functions of PARs is regulation of exocrine secretion in the salivary glands, pancreas and GI mucosal epithelium. PARs also modulate motility of GI smooth muscle, involving multiple mechanisms. PAR2 appears to play dual roles in pancreatitis and related pain, being pro-inflammatory/pro-nociceptive and anti-inflammatory/anti-nociceptive. Similarly, dual roles for PAR1 and PAR2 have been demonstrated in mucosal inflammation/damage throughout the GI tract. There is also fundamental and clinical evidence for involvement of PAR2 in colonic pain. PARs are thus considered key molecules in regulation of GI functions and targets for development of drugs for treatment of various GI diseases.
  • Signal transduction for formation/release of interleukin-8 caused by a PAR2-activating peptide in human lung epithelial cells, Kazumi Moriyuki, Mami Nagataki, Fumiko Sekiguchi, Hiroyuki Nishikawa, Atsufumi Kawabata, REGULATORY PEPTIDES, REGULATORY PEPTIDES, 145(1-3), 42 - 48, Jan. 2008 , Refereed
    Summary:Proteinase-activated receptor-2 (PAR2) plays a dual role in the respiratory system, being pro- and anti-inflammatory. In human lung epithelial cells (A549), PAR2 activation causes release of interleukin-8 (IL-8) in addition to prostaglandin E-2 (PGE(2)). In the present study, we thus investigated PAR2-triggered signal transduction pathways causing IL-8 formation in A549 cells. SLIGRL-NH2, a PAR2-activating peptide, but not LSIGRL-NH2,, a scrambled peptide, elicited release of IL-8 from A549 cells for 18 h, as measured by the ELISA method, an effect being suppressed by inhibitors of MEK, JNK, EGF receptor-tyrosine kinase (EGFR-TK), Src, pan-tyrosine kinases and protein kinase C, but not p38 MAP kinase or cyclooxygenase. SLIGRL-NH2, also up-regulated IL-8 at protein and mRNA levels, as determined by Western blotting and RTPCR, respectively. The PAR2-triggered up-regulation of IL-8 protein and mRNA was blocked by an inhibitor of MEK, but not clearly by inhibitors of JNK and EGFR-TK. SLIGRL-NH2 actually phosphorylated JNK as well as ERK, the JNK activation being resistant to inhibitors of Src, pan-tyrosine kinases, protein kinase C and EGFR-TK. Our data suggest that PAR2-triggerd IL-8 formation involves transcriptional upregulation of IL-8 via the MEK-ERK pathway, while the JNK and EGF receptor pathways might rather contribute to a post-transcriptional process for the release of IL-8. (c) 2007 Elsevier B.V. All rights reserved.
  • Hydrogen sulfide inhibits activity of three isoforms of recombinant nitric oxide synthase, Atoko Kubo, Yuko Kurokawa, Ichiko Doe, Takashi Masuko, Fumiko Sekiguchi, Atsufumi Kawabata, TOXICOLOGY, TOXICOLOGY, 241(1-2), 92 - 97, Nov. 2007 , Refereed
    Summary:To clarify the presence of cross-talk between H2S and NO, we investigated effect of NaHS, an H2S donor, on activity of recombinant NO synthase (NOS) isoforms. Activity of all nNOS, iNOS and eNOS was inhibited by NaHS (IC50: 0.13-0.21 mM). In contrast, Na2SO3, L-Cysteine and threo-1,4-dimercapto-2,3-butanediol, a reductant, exerted poor inhibition of NOS activity. Increasing concentrations of tetrahydrobiopterin (BH4) reversed the NaHS inhibition of nNOS and eNOS, but not iNOS. Our data thus demonstrate inhibition of three NOS isoforms by NaHS/H2S, and suggest involvement of interaction of NaHS/H2S with BH4 in inhibition of nNOS and eNOS, but not iNOS. (C) 2007 Elsevier Ireland Ltd. All rights reserved.
  • A protective role of hydrogen sulfide against oxidative stress in rat gastric mucosal epithelium, Daiki Yonezawa, Fumiko Sekiguchi, Misato Miyamoto, Eiichi Taniguchi, Masami Honjo, Takashi Masuko, Hiroyuki Nishikawa, Atsufumi Kawabata, TOXICOLOGY, TOXICOLOGY, 241(1-2), 11 - 18, Nov. 2007 , Refereed
    Summary:We investigated effect of hydrogen sulfide (H2S) on oxidative stress-caused cell death in gastric mucosal epithelial cells. In rat normal gastric epithelial RGM1 cells, NaHS, a H2S donor, at 1.5 mM strongly suppressed hydrogen peroxide (H2O2)-caused cell death, while it slightly augmented the H2O2 toxicity at 0.5-1 mM. The protective effect of NaHS was abolished by inhibitors of MEK or JNK, but not of p38 MAP kinase. NaHS at 1.5 mM actually phosphorylated ERK and JNK in RGM1 cells. Glibenclamide, an ATP-sensitive K+ (K-ATP(+)) channel inhibitor, did not affect the protective effect of NaHS, although mRNAs for K(ATP)(+)channel subunits, Kir6.1 and SUR1, were detected in RGM1 cells. In anesthetized rats, oral administration of NaHS protected against gastric mucosal lesion caused by ischemia-reperfusion. These results suggest that NaHS/H2S may protect gastric mucosal epithelial cells against oxidative stress through stimulation of MAP kinase pathways, a therapeutic dose range being very narrow. (C) 2007 Elsevier Ireland Ltd. All rights reserved.
  • Hydrogen sulfide as a novel nociceptive messenger, Atsufumi Kawabata, Tsuyoshi Ishiki, Kelta Nagasawa, Shigeru Yoshida, Yumi Maeda, Tomoko Takahashi, Fumiko Sekiguchi, Tetsuyuki Wada, Seiji Ichida, Hiroyuki Nishikawa, PAIN, PAIN, 132(1-2), 74 - 81, Nov. 2007 , Refereed
    Summary:Hydrogen sulfide (H2S), an endogenous gasotransmitter, modulates various biological events such as inflammation in the mammalian body. The present study investigated possible involvement of H2S in peripheral nociceptive processing. Intraplantar (i.pl.) administration of NaHS, a H2S donor, produced prompt hyperalgesia in rats, accompanied by expression of Fos in the spinal dorsal horn. The H2S-evoked hyperalgesia was blocked by 5,5'-dithio-bis-(2-nitrobenzoic acid) (DTNB), an oxidizing agent, or ethosuximide and mibefradil, T-type Ca2+ channel inhibitors. L-Cysteine, an endogenous source for H2S, given i.pl., also elicited hyperalgesia, an effect being abolished by DL-propargylglycine (PPG) and beta-cyanoalanine (BCA), inhibitors of cystathionine-gamma-lyase, a H2S synthesizing enzyme. PPG and/or BCA partially inhibited the hyperalgesia induced by i.pl. lipopolysaccharide, an effect being reversed by i.pl. NaHS. In the patch-clamp study using undifferentiated NG108-15 cells that express T-type, but not other types, of Ca2+ channels, NaHS enhanced the currents through the T-type channels, an effect being blocked by DTNB. Thus, H2S appears to function as a novel nociceptive messenger through sensitization of T-type Ca2+ channels in the peripheral tissues, particularly during inflammation. (C) 2007 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.
  • The proteinase inhibitor camostat mesilate suppresses pancreatic pain in rodents, Hiroyasu Ishikura, Sachiyo Nishimura, Maho Matsunami, Toshifumi Tsujiuchi, Tsuyoshi Ishiki, Fumiko Sekiguchi, Mitsuhide Naruse, Toshio Nakatani, Yoshihisa Kamanaka, Atsufumi Kawabata, LIFE SCIENCES, LIFE SCIENCES, 80(21), 1999 - 2004, May 2007 , Refereed
    Summary:Camostat mesilate, an orally available proteinase inhibitor, is clinically used for treatment of pancreatitis. Given recent evidence that pancreatic proteinases including trypsin and/or proteinase-activated receptor-2 (PAR2) might be involved in pancreatic pain, we examined if camostat mesilate could suppress spinal Fos expression, a marker for neuronal activation, following specific application of trypsin to the pancreas, and pancreatitis-related referred allodynia. Trypsin, administered into the pancreatic duct, caused delayed expression of Fos proteins in the superficial layer of the bilateral T8 and T9 spinal dorsal horns in rats. The trypsin-induced spinal Fos expression was completely abolished by oral preadministration of camostat mesilate at 300 mg/kg. After hourly repeated (6 times in total) administration of caerulein, mice showed typical symptoms of pancreatitis, accompanied by mechanical allodynia in the upper abdomen (i.e., referred hyperalgesia/allodynia), as assessed by use of von Frey filaments. Camostat mesilate at 100-300 mg/kg, given orally twice before the 1st and 4th doses of cacrulein, abolished the pancreatitis-related abdominal allodynia, while it partially prevented the inflammatory signs. The same doses of camostat mesilate, when administered once after the final dose of caerulein, also revealed significant anti-allodynic effect. These data suggest that camostat mesilate prevents and/or depresses pancreatitis-induced pain and/or referred hyperalgesia/allodynia, in which proteinases including trypsin would play a critical role. (C) 2007 Elsevier Inc. All rights reserved.
  • Mechanisms for prostaglandin E-2 formation caused by proteinase-activated receptor-1 activation in rat gastric mucosal epithelial cells, Fumiko Sekiguchi, Shino Saito, Kaori Takaoka, Hitomi Hayashi, Mami Nagataki, Keita Nagasawa, Hiroyuki Nishikawa, Hirofumi Matsui, Atsufumi Kawabata, BIOCHEMICAL PHARMACOLOGY, BIOCHEMICAL PHARMACOLOGY, 73(1), 103 - 114, Jan. 2007 , Refereed
    Summary:Proteinase-activated receptor-1 (PAR1), a thrombin receptor, plays a protective role in gastric mucosa via prostanoid formation. Thus, we studied effects of PAR1 stimulation on prostaglandin E-2 (PGE(2)) formation in rat normal gastric mucosal epithelial RGM1 cells and analyzed the underlying signal transduction mechanisms. The PARI-activating peptide (PAR1-AP) and thrombin increased PGE(2) release from RGM1 cells for 18 h, an effect being suppressed by inhibitors of COX-1, COX-2, MEK, p38 MAP kinase (p38 MAPK), protein kinase C (PKC), Src and EGF receptor-tyrosine kinase (EGFR-TK), but not JNK and matrix metalloproteinase (MMP)/a disintegrin and metalloprotemases (ADAMs). PAR1-AP caused persistent (6 h or more) and transient (5 min) phosphorylation of ERK and p38 MAPK, respectively, followed by delayed reinforcement at 18 h. PAR1-AP up-regulated COX-2 in a manner dependent on MEK and EGFR-TK, but not p38 MAPK. The PARI-mediated persistent ERK phosphorylation was reduced by inhibitors of Src and EGFR-TK. PAR1-AP actually phosphorylated EGF receptors and up-regulated mRNA for heparin-binding-EGF (HB-EGF), the latter effect being blocked by inhibitors of Src, EGFR-TK and MEK. Heparin, an inhibitor for HB-EGF, suppressed PAR1-mediated PGE2 formation and persistent ERK phosphorylation. These results suggest that PAR1 up-regulates COX-2 via persistent activation of MEK/ERK that is dependent on EGFR-TK activation following induction of HB-EGF, leading to PGE(2) formation. In addition, our data also indicate involvement of COX-1, PKC and p38 MAPK in PAR1-triggered PGE(2) formation. PAR1, thus stimulates complex multiple signaling pathways responsible for PGE(2) formation in RGM1 cells. (c) 2006 Elsevier Inc. All rights reserved.
  • Antiallodynic effect of etidronate, a bisphosphonate, in rats with adjuvant-induced arthritis: Involvement of ATP-sensitive K+ channels, Atsufumi Kawabata, Naoyuki Kawao, Yoshimi Hironaka, Tsuyoshi Ishiki, Maho Matsunami, Fumiko Sekiguchi, NEUROPHARMACOLOGY, NEUROPHARMACOLOGY, 51(2), 182 - 190, Aug. 2006 , Refereed
    Summary:Bisphosphonates, pyrophosphate analogues, known as inhibitors of bone resorption, appear to cause analgesia in certain clinical painful situations. To detect clinically relevant analgesic property of etidronate, a non-aminobisphosphonate, we examined and characterized its antiallodynic effect in the rat with adjuvant-induced arthritis, in comparison with alendronate, an aminobisphosphonate, as determined by the von Frey test. Repeated systemic administration of etidronate at 10-40 mg/kg/day suppressed the adjuvant-induced mechanical allodynia in rat hindpaw, an effect reaching a plateau in approximately 10 days. Systemic or intraplantar (i.pl.) administration of ATP-sensitive K+ (K-ATP(+)) channel inhibitors, glibenclamide and/or tolbutamide, completely reversed the antiallodynic effect of etidronate within 1 h in the arthritic rats, without affecting the nociceptive scores in naive or arthritic animals that had not received etidronate. Alendronate, administered repeatedly, also revealed similar glibenclamide-reversible antiallodynic effect. In contrast, the antiallodynic effect of repeated systemic indomethacin was resistant to i.pl. glibenclamide in the arthritic rats. Repeated administration of etidronate or alendronate only slightly attenuated the adjuvant-evoked hindpaw edema. Among K-ATP(+) channel subunits, mRNAs for Kir6.1, SUR1, SUR2A and SUR2B were abundant in rat dorsal root ganglia, while Kir6.2 mRNA was poor. Our data demonstrate that repeated etidronate as well as alendronate exhibits antiallodynic activity in arthritic rats, which might be clinically relevant, and suggest involvement of K-ATP(+) channels in the underlying mechanisms. (c) 2006 Elsevier Ltd. All rights reserved.
  • Suppression of pancreatitis-related allodynia/hyperalgesia by proteinase-activated receptor-2 in mice, A Kawabata, M Matsunami, M Tsutsumi, T Ishiki, O Fukushima, F Sekiguchi, N Kawao, T Minami, T Kanke, N Saito, BRITISH JOURNAL OF PHARMACOLOGY, BRITISH JOURNAL OF PHARMACOLOGY, 148(1), 54 - 60, May 2006 , Refereed
    Summary:1 Proteinase-activated receptor-2 (PAR2), a receptor activated by trypsin and tryptase, is abundantly expressed in the gastrointestinal tract including the C-fiber terminal, and might play a role in processing of visceral pain. In the present study, we examined and characterized the roles of PAR2 in pancreatitis-related abdominal hyperalgesia/allodynia in mice. 2 Caerulein, administered i.p. once, caused a small increase in abdominal sensitivity to stimulation with von Frey hairs, without causing pancreatitis, in PAR2-knockout (KO) mice, but not wild-type (WT) mice. 3 Caerulein, given hourly six times in total, caused more profound abdominal hyperalgesia/allodynia in PAR2-KO mice, as compared with WT mice, although no significant differences were detected in the severity of pancreatitis between the KO and WT animals. 4 The PAR2-activating peptide, 2-furoyl-LIGRL-NH2, coadministered repeatedly with caerulein six times in total, abolished the caerulein-evoked abdominal hyperalgesia/allodynia in WT, but not PAR2-KO, mice. Repeated doses of 2-furoyl-LIGRL-NH2 moderately attenuated the severity of caerulein-induced pancreatitis in WT animals. 5 Our data from experiments using PAR2-KO mice provide evidence that PAR2 functions to attenuate pancreatitis-related abdominal hyperalgesia/allodynia without affecting pancreatitis itself, although the PAR2AP applied exogenously is not only antinociceptive but also anti-inflammatory.
  • Mechanisms for modulation of mouse gastrointestinal motility by proteinase-activated receptor (PAR)-1 and-2 in vitro, F Sekiguchi, N Hasegawa, K Inoshita, D Yonezawa, N Inoi, T Kanke, N Saito, A Kawabata, LIFE SCIENCES, LIFE SCIENCES, 78(9), 950 - 957, Jan. 2006 , Refereed
    Summary:Proteinase-activated receptor (PAR)-1 or -2 modulates gastrointestinal transit in vivo. To clarify the underlying mechanisms, we characterized contraction/relaxation caused by TFLLR-NH2 and SLIGRL-NH2, PAR-1- and -2-activating peptides, respectively, in gastric and small intestinal (duodenal, jejunal and ileal) smooth muscle isolated from wild-type and PAR-2-knockout mice. Either SLIGRL-NH2 or TFLLR-NH2 caused both relaxation and contraction in the gastrointestinal preparations from wild-type animals. Apamin, a K+ channel inhibitor, tended to enhance the peptide-evoked contraction in some of the gastrointestinal preparations, whereas it inhibited relaxation responses to either peptide completely in the stomach, but only partially in the small intestine. Indomethacin reduced the contraction caused by SLIGRL-NH2 or TFLLR-NH2 in both gastric and ileal preparations, but unaffected apamin-insensitive relaxant effect of either peptide in ileal preparations. Repeated treatment with capsaicin suppressed the contractile effect of either peptide in the stomach, but not clearly in the ileum, whereas it enhanced the apamin-insensitive relaxant effect in ileal preparations. In any gastrointestinal preparations from PAR-2-knockout mice, SLIGRL-NH2, produced no responses. Thus, the inhibitory component in tension modulation by PAR-1 and -2 involves both apamin-sensitive and -insensitive mechanisms in the small intestine, but is predominantly attributable to the former mechanism in the stomach. The excitatory component in the PAR-1 and -2 modulation may be mediated, in part, by activation of capsaicin-sensitive sensory nerves and/or endogenous prostaglandin formation. Our study thus clarifies the multiple mechanisms for gastrointestinal motility modulation by PAR-1 and -2, and also provides ultimate evidence for involvement of PAR-2. (c) 2005 Elsevier Inc. All rights reserved.
  • Signal transduction for proteinase-activated receptor-2-triggered prostaglandin E-2 formation in human lung epithelial cells, N Kawao, M Nagataki, K Nagasawa, S Kubo, K Cushing, T Wada, F Sekiguchi, S Ichida, MD Hollenberg, WK MacNaughton, H Nishikawa, A Kawabata, JOURNAL OF PHARMACOLOGY AND EXPERIMENTAL THERAPEUTICS, JOURNAL OF PHARMACOLOGY AND EXPERIMENTAL THERAPEUTICS, 315(2), 576 - 589, Nov. 2005 , Refereed
    Summary:We investigated proteinase-activated receptor-2 (PAR(2))-triggered signal transduction pathways causing increased prostaglandin E-2 (PGE(2)) formation in human lung-derived A549 epithelial cells. The PAR(2) agonist, SLIGRL-NH2 (Ser-Leu-Ile-Gly-Arg-Leu-amide), evoked immediate cytosolic Ca2+ mobilization and delayed (0.5-3 h) PGE(2) formation. The PAR(2)-triggered PGE(2) formation was attenuated by inhibition of the following signal pathway enzymes: cyclooxygenases 1 and 2 (COX-1 and COX-2, respectively), cytosolic Ca2+-dependent phospholipase A(2) (cPLA(2)), the mitogenactivated protein kinases (MAPKs), mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK)-extracellular signal-regulated kinase (ERK) and p38 MAPK, Src family tyrosine kinase, epidermal growth factor (EGF) receptor tyrosine kinase (EGFRK), and protein kinase C (PKC), but not by inhibition of matrix metalloproteinases. SLIGRL-NH2 caused prompt ( 5 min) and transient ERK phosphorylation, blocked in part by inhibitors of PKC and tyrosine kinases but not by an EGFRK inhibitor. SLIGRL-NH2 2 also evoked a relatively delayed (15 min) and persistent (30 min) phosphorylation of p38 MAPK, blocked by inhibitors of Src and EGFRK but not by inhibitors of COX-1 or COX-2. SLIGRL-NH2 elicited a Src inhibitor-blocked prompt (5 min) and transient phosphorylation of the EGFRK. SLIGRL-NH2 up-regulated COX-2 protein and/or mRNA levels that were blocked by inhibition of p38 MAPK, EGFRK, Src, and COX-2 but not MEK-ERK. SLIGRL-NH2 also caused COX-1-dependent up-regulation of microsomal PGE synthase-1 (mPGES-1). We conclude that PAR(2)-triggered PGE(2) formation in A549 cells involves a coordinated up-regulation of COX-2 and mPGES-1 involving cPLA(2), increased cytosolic Ca2+, PKC, Src, MEK-ERK, p38 MAPK, Src-mediated EGF receptor trans-activation, and also metabolic products of both COX-1 and COX-2.
  • 2-Furoyl-LIGRL-NH2, a potent agonist for proteinase-activated receptor-2, as a gastric mucosal cytoprotective agent in mice, A Kawabata, Y Oono, D Yonezawa, K Hiramatsu, N Inoi, F Sekiguchi, M Honjo, M Hirofuchi, T Kanke, H Ishiwata, BRITISH JOURNAL OF PHARMACOLOGY, BRITISH JOURNAL OF PHARMACOLOGY, 144(2), 212 - 219, Jan. 2005 , Refereed
    Summary:1 Proteinase-activated receptor-2 (PAR(2)), expressed in capsaicin-sensitive sensory neurons, plays a protective role in gastric mucosa. The present study evaluated gastric mucosal cytoprotective effect of 2-furoyl-LIGRL-NH2, a novel highly potent PAR(2) agonist, in ddY mice and in wild-type and PAR(2)-knockout mice of C57BL/6 background. 2 Gastric mucosal injury was created by oral administration of HCl/ethanol solution in the mice. The native PAR(2)-activating peptide SLIGRL-NH2, administered intraperitoneally (i.p.) at 0.3 - 1 mumol kg(-1) in combination with amastatin, an aminopeptidase inhibitor, but not alone, revealed gastric mucosal protection in ddY mice, which was abolished by ablation of capsaicin-sensitive sensory neurons. 3 I.p. administration of 2-furoyl-LIGRL-NH2 at 0.1 mumol kg(-1), without combined treatment with amastatin, exhibited gastric mucosal cytoprotective activity in ddY mice, the potency being much greater than SLIGRL-NH2 in combination with amastatin. This effect was also inhibited by capsaicin pretreatment. 4 Oral administration of 2-furoyl-LIGRL-NH2 at 0.003 - 0.03 mumol kg(-1) also protected against gastric mucosal lesion in a capsaicin-reversible manner in ddY mice. 5 I.p. 2-furoyl-LIGRL-NH2 at 0.1 - 0.3 mumol kg(-1) caused prompt salivation in anesthetized mice, whereas its oral administration at 0.003 - 1 mumol kg(-1) was incapable of eliciting salivation. 6 In wild-type, but not PAR(2)-knockout, mice of C57BL/6 background, i.p. administration of 2-furoyl-LIGRL-NH2 caused gastric mucosal protection. 7 Thus, 2-furoyl-LIGRL-NH2 is considered a potent and orally available gastric mucosal protective agent. Our data also substantiate a role for PAR2 in gastric mucosal protection and the selective nature of 2-furoyl-LIGRL-NH2.
  • Effects of L-arginine on spontaneous contraction of the rat portal vein, K Shimamura, M Zhou, M Toba, S Kimura, T Higuchi, H Kawaguchi, F Sekiguchi, S Sunano, PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY, PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY, 446(1), 30 - 35, Apr. 2003 , Refereed
    Summary:The effects Of L-arginine on spontaneous contraction of endothelium-denuded longitudinal preparations of the rat portal vein were studied. L-Arginine increased the frequency of spontaneous contraction concentration-dependently between 10 muM and 1 mM. Changes in contraction amplitude and duration were not remarkable. D-Arginine had a negligible effect on spontaneous contraction. N-omega-nitro-L-arginine (1 mM) did not affect spontaneous contraction or the response to L-arginine. Addition of N-G-monomethyl-L-arginine (1 mM), L-lysine (1 mM) or N-ethymaleimide (0.1 mM) increased the frequency of spontaneous contractions and inhibited the. effect Of L-arginine. Glibenclamide (10 muM) did not affect spontaneous contraction or the response to L-arginine. Spontaneous increase in concentration of intracellular Ca2+, estimated as the ratio of Fura-PE3 fluorescence occurred synchronously with spontaneous contraction. Spontaneous increase in concentration of intracellular Ca2+ occurred more frequently in the presence Of L-arginine (I MM). L-Arginine (1 mM) also increased the number of action potential bursts/min in the longitudinal smooth muscle layer. L-Arginine (I mM) also depolarized cell membranes. This study indicates that L-arginine increases the frequency of spontaneous contraction of longitudinal muscle in the rat portal vein by membrane depolarization through mechanisms that do not involve, nitric oxide or the inhibition of ATP-sensitive K+ channels.
  • Caffeine-induced contracture in oesophageal striated muscle of normotensive and hypertensive rats, F Sekiguchi, K Kawata, M Komori, S Sunano, EUROPEAN JOURNAL OF PHARMACOLOGY, EUROPEAN JOURNAL OF PHARMACOLOGY, 465(1-2), 153 - 161, Mar. 2003 , Refereed
    Summary:To elucidate whether properties of the sarcoplasmic reticulum are altered, not only in vascular smooth muscle, but also in visceral striated muscle of spontaneously hypertensive rats (SHR), caffeine-induced contractures in oesophageal striated muscle of Wistar Kyoto rats (WKY) and stroke-prone SHR (SHRSP) were compared. In both preparations, 30 mM caffeine induced a contracture with two components. The second component, which was diminished by extracellular Ca2+ removal or Ni2+ but not by verapamil, was much smaller in SHRSP. Both components and differences between WKY and SHRSP coincided with changes in intracellular Ca2+. Although membrane potential was identical between these preparations, caffeine induced slight depolarization only in WKY preparations. Similar depolarization was observed with 10 mM K+, which induced no contraction. It is suggested that the first and the second components of caffeine-induced contracture were induced by Ca2+ released from sarcoplasmic reticulum and by Ca2+ that entered through channels activated by sarcoplasmic reticulum Ca2+ depletion, respectively In SHRSP preparations, Ca2+ from the latter pathway was clearly decreased, although this change is thought not to be related to the initiation of hypertension. These results suggest that Ca2+ handling properties of cell membrane and sarcoplasmic reticulum are generally altered in muscles of SHRSP. (C) 2003 Elsevier Science B.V. All rights reserved.
  • Tension oscillation in arteries and its abnormality in hypertensive animals, K Shimamura, F Sekiguchi, S Sunano, CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, 26(4), 275 - 284, Apr. 1999
    Summary:1. The mechanisms of oscillatory contraction of arterial smooth muscle in vitro are discussed. 2. The membrane potential and cytoplasmic free Ca2+ concentration in smooth muscle cells oscillate in the presence of agonists. 3. The oscillatory change in the membrane potential of smooth muscle cells is related to Ca2+ release from intracellular stores. 4. Gap junctions between smooth muscle cells play important roles in the synchronized oscillation of the cytoplasmic free Ca2+ concentration in this population of cells. 5. Endothelial cells may increase or decrease the tension oscillation of smooth muscle cells. 6. In arteries from hypertensive rats, an increase in membrane excitability and the number of gap junctions between smooth muscle cells and impaired endothelial function are the main factors responsible for the modulation of tension oscillation.
  • Spontaneous and agonist-induced contractions and endothelium-dependent relaxation in aortae from SHRSP and WKY rats under various levels of passive force, F Sekiguchi, T Adachi, H Matsubara, K Matsuda, K Kita, K Shimamura, S Sunano, CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, 23(6-7), 483 - 489, Jun. 1996 , Refereed
    Summary:1. The influence of the passive force on the contraction and endothelium-dependent relaxation in aortae of normotensive Wister Kyoto (WKY) rats and stroke-prone spontaneously hypertensive rats (SHRSP) Here compared. 2. Force changes of endothelium-intact and -removed preparations were measured isometrically by a force-displacement transducer, Endothelium-dependent relaxation was observed by applying acetylcholine to the preparation precontracted in the presence of 5 x 10(-7) mol/L noradrenaline. 3. The preparations showed spontaneously developed tension (tone) that increased with the increase in the passive force. The effect of passive force was greater in preparations from SHRSP. Contraction initiated by noradrenaline was also increased by passive force up to 30 mN, then showed a tendency to decrease. 4. Endothelium-dependent relaxation was depressed as the passive force was increased. Preparations from SHRSP showed impaired endothelium-dependent relaxation and were influenced by passive force to a lesser degree when compared with preparations from WKY rats. 5. Relaxation by sodium nitroprusside was influenced by passive force to a much lesser extent than that by acetylcholine. 6. Indomethacin potentiated endothelium-dependent relaxation and blocked the effect of passive force in both preparations. 7. The difference in relaxation and the effect of passive force is primarily caused by the difference in the release of endothelium-derived contracting factor, which is thought to be a product of the cyclo-oxygenase pathway of the arachidonic acid cascade.
  • THE PRESENCE OF LOW-MOLECULAR-WEIGHT GERMINATIVE SUBSTANCES IN BACILLUS-CEREUS T-SPORE EXTRACT, H SHIBATA, Y ODAHARA, F SASAKI, O HIROTA, M NISHIDA, TANI, I, MICROBIOLOGY AND IMMUNOLOGY, MICROBIOLOGY AND IMMUNOLOGY, 38(7), 519 - 525, 1994 , Refereed
    Summary:An extract from intact spores of Bacillus cereus T having a germination-inducing activity was studied. Two distinct germinative principles were found through dialysis of the extract. One was diffusible through the dialysis membrane and the other was non-diffusible. The activity of the former fraction was inhibited by the addition of 1 mM glyeoletherdiamine-N,N,N',N'-tetraacetic acid (GEDTA), whereas the latter fraction was inactive unless GEDTA was added to the assay system. The diffusible principle maintained the major portion of the activity found in the crude spore extract. By means of high-performance liquid chromatography (HPLC) using a gel permeation chromatography column, 9 fractions were obtained from the deproteinized diffusible fraction. Of those fractions, two fractions (No. 1 and No. 8) were responsible for the germination-inducing activity, but no reconstituted activity was observed unless both fractions No. 1 and No. 8 were added to the assay system. Amino acid analysis of fraction No. 1 revealed that the fraction was rich in free amino acids, especially in alanine. On the other hand, by the use of reverse-phase HPLC and fast atom bombardment mass spectrometry, it was concluded that the effective substance in fraction No. 8 was inosine. Based on these findings, it was suggested that the active substances in fraction No. I might be a free amino acid such as L-alanine and/or Ca2+ and a Ca2+-binding substance.

Books etc

  • Inhibitory role of nitric oxide in the contraction of circular muscle of rat portal vein(共著), The Bioloby of Nitric Oxide Part 6 Portland Press Ltd, London,   1998

Conference Activities & Talks

  • AKAP-dependent modulation of phosphorylation levels of Cav3.2 T-type calcium channels by protein kinase A and calcineurin: implications for mechanical pain sensitivity., Neuroscience 2011,   2011 11 , Neuroscience 2011
  • Sensitization of T-type calcium channels by prostaglandin E2 via the EP4 receptor/cyclic AMP/protein kinase A pathway: a possible mechanism for mechanical hyperalgesia., Neuroscience 2011,   2011 11 , Neuroscience 2011
  • Analysis of various biological responses induced by Helicobacter pylori extract: independent of proteinase-activated receptors?, 6th World Congress on Basic and Clinical Pharmacology (WorldPharma2010),   2010 07 , 6th World Congress on Basic and Clinical Pharmacology (WorldPharma2010)
  • Hydrogen sulfide promotes function of T-type calcium channels and secretion of prostatic acid phosphatase in neuroendocrine-like prostate cancer cells from the androgen-sensitive LNCaP cell line, 16th World Congress on Basic and Clinical Pharmacology (WorldPharma2010),   2010 07 , 16th World Congress on Basic and Clinical Pharmacology (WorldPharma2010)
  • Analysis of cellular signaling for epidermal growth factor-mediated suppression of androgen-induced expression of prostate-specific antigen gene in human prostate cancer LNCaP cells, 16th World Congress on Basic and Clinical Pharmacology (WorldPharma2010),   2010 07 , 16th World Congress on Basic and Clinical Pharmacology (WorldPharma2010)
    Summary:Maeda, Y., Yamanaka, R., Sekiguchi, F., Kawabata, A. , 2010, 7, 17-23, Copenhagen, Denmark.
  • Peripheral hyperalgesia via the cyclic AMP/protein kinase A pathway involves activation of T-type calcium channels in rats., 16th World Congress on Basic and Clinical Pharmacology (WorldPharma2010),   2010 07 , 16th World Congress on Basic and Clinical Pharmacology (WorldPharma2010)
  • Involvement of downstream Src activation of Cav3.2 T-type calcium channels in hydrogen sulfide-induced neuronal differentiation in NG108-15 cells., 13th Congress of the European Federation of Neurological Societies (EFNS 2009),   2009 09 , 13th Congress of the European Federation of Neurological Societies (EFNS 2009)
  • Neurite outgrowth and functional up-regulation of voltage-dependent calcium channels caused by cyclic AMP in sensory neuron-like cells., 13th Congress of the European Federation of Neurological Societies (EFNS 2009),   2009 09 , 13th Congress of the European Federation of Neurological Societies (EFNS 2009)
  • Effect of Helicobacter pylori extracts on prostaglandin E2 production in human lung alveolar epithelial A549 cells., XXXVI International Congress of Physiological Sciences,   2009 08 , XXXVI International Congress of Physiological Sciences
  • The time lag of PGE2 release and COX-2 up-regulation triggered by PAR1 is due to deficiency of arachidonic acid in gastric epithelial cells., XXXVI International Congress of Physiological Sciences,   2009 08 , XXXVI International Congress of Physiological Sciences
  • The delayed release of PGE2 mediated by PAR1 involves slowly developing production of arachidonic acid in rat gastric mucosal epithelical cells., Experimental Biology 2009,   2009 04 , Experimental Biology 2009
  • Relationship between expression of PARs and infection with H. pylori in the stomach of gastric cancer patients., Experimental Biology 2009,   2009 04 , Experimental Biology 2009
  • IL-8 release triggered by proteinase-activated receptor-2 stimulation involves both MEK/ERK and PI3 kinase/Akt pathways in gastrointestinal epithelial cells., Experimental Biology 2009,   2009 04 , Experimental Biology 2009
  • Hydrogen sulfide induces neuronal differentiation via Cav3.2 T-type calcium channels and Src family tyrosine kinase in NG108-15 cells., 6th FENS Forum of European Neuroscience,   2008 07 , 6th FENS Forum of European Neuroscience
  • Involvement of endogenous hydrogen sulfide in acute pancreatitis-related pain., 6th FENS Forum of European Neuroscience,   2008 07 , 6th FENS Forum of European Neuroscience
  • Cell damage induced by hydrogen sulfide in cortical neurons from mouse embryos., 6th FENS Forum of European Neuroscience,   2008 07 , 6th FENS Forum of European Neuroscience
  • Hydrogen sulfide is pro-nociceptive in the spinal cord as well as peripheral tissues., 6th FENS Forum of European Neuroscience,   2008 07 , 6th FENS Forum of European Neuroscience
  • Hydrogen sulfide as a nociceptive messenger in rat and mouse pancreata., Neuroscience 2007,   2007 11 , Neuroscience 2007
  • A pro-nociceptive role for hydrogen sulfide in the pancreas., The 4th Science and Research Symposium:,   2007 08 , The 4th Science and Research Symposium:
    Summary:9. Kawabata, A., Nishimura, S., Fukushima, O., Ishikura, H., Takahashi, T., Matsunami, M., Sekiguchi, F., Naruse, M. 2007, 8, 28, Nagoya.
  • Inhibition of the activity of three recombinant nitric oxide synthase isoforms by hydrogen sulfide., Young Life Scientists’ Symposium 2007,   2007 07 , Young Life Scientists’ Symposium 2007
  • Hydrogen sulfide (H2S) as a hypothetical pro-inflammatory signaling molecule in ulcerative colitis (UC): impaired detoxification but not generation of H2S in a mouse UC model., Young Life Scientists’ Symposium 2007,   2007 07 , Young Life Scientists’ Symposium 2007
  • Modulation of PAR1-triggered prostaglandin E2 production by thiazolidinediones through peroxisome proliferator-activated receptor-γ-independent pathways in rat gastric mucosal epithelial cells., Young Life Scientists’ Symposium 2007,   2007 07 , Young Life Scientists’ Symposium 2007
  • Curcumin intervention of PAR2-triggered prostaglandin E2 (PGE2) release in human lung epithelial cells: what are the target molecules downstream of PAR2?, Young Life Scientists’ Symposium 2007,   2007 07 , Young Life Scientists’ Symposium 2007
  • Effects of hydrogen sulfide on the tone of gastrointestinal and airway smooth muscle preparations from rodents., Life Sciences 2007,   2007 07 , Life Sciences 2007
  • Hydrogen sulfide sensitizes T-type calcium channels via redox modulation., Neuroscience 2006,   2006 10 , Neuroscience 2006
  • Prostaglandin E2 production triggered by proteinase-activated receptor-1 in rat gastric mucosal epithelial cells: Cell signaling and modulation by peroxisome proliferator-activated receptor-γ ligands., Half-day Symposium on G Protein-Coupled Receptors (GPCRs),   2006 09 , Half-day Symposium on G Protein-Coupled Receptors (GPCRs)
  • Evidence that hydrogen sulfide plays a pro-nociceptive role., The 18th Japan-Korea Joint Seminar of Pharmacology, 2006, 9, 23-24, Fukui.,   2006 09 , The 18th Japan-Korea Joint Seminar of Pharmacology, 2006, 9, 23-24, Fukui.
  • COX-2 up-regulation and prostaglandin E2 production triggered by proteinase-activated receptor-1 (PAR1) and their facilitation by peroxisome proliferator-activated receptor-γ ligands in rat gastric mucosal epithelial cells., The Inernational Mini-Symposium on Gastrointestinal Pharmacology,   2006 07 , The Inernational Mini-Symposium on Gastrointestinal Pharmacology
  • Distinct signaling and actions caused by intracellular ligands (pepducins) for proteinase-activated receptor-1 in multiple cells/tissues., Cell Signaling World 2006,   2006 01 , Cell Signaling World 2006
  • Cell signaling by proteinase-activated receptor-2 for interleukin-8 formation in human lung epithelial cells., Cell Signaling World,   2006 01 , Cell Signaling World
    Summary:33. Kawabata, A., Nagataki, M., Moriyuki, K., Sekiguchi, F., Nishikawa, H. 2006, 1, 25-28, Luxembourg. (Oral presentation)
  • Luminal trypsin causes delayed facilitation of capsaicin-evoked visceral nociception by activating protease-activated receptor-2., Neuroscience 2004,   2004 10 , Neuroscience 2004
  • Protease-activated receptors (PARs) and respiratory functions: cellular signaling and enhancement of prostanoid formation in the epithelium., The 17th Korea-Japan Joint Seminar on Pharmacology,   2004 09 , The 17th Korea-Japan Joint Seminar on Pharmacology
  • Inhibitory and excitatory modulations of mouse gastrointestinal motility by activation of proteinase-activated receptor (PAR)-1 and PAR-2., The 17th Korea-Japan Joint Seminar on Pharmacology,   2004 09 , The 17th Korea-Japan Joint Seminar on Pharmacology
  • The intracellular agonist and antagonist (pepducins) for proteinase-activated receptor-1: distinct activity in multiple cells/tissues., The 17th Korea-Japan Joint Seminar on Pharmacology,   2004 09 , The 17th Korea-Japan Joint Seminar on Pharmacology
  • Protease-activated receptor-2 activation induces delayed facilitation of capsaicin-evoked visceral pain in mice: involvement of endogenous bradykinin., 11th International Pain Clinic World Society of Pain Clinicians,   2004 07 , 11th International Pain Clinic World Society of Pain Clinicians
  • Signal transduction mechanisms for prostanoid formation caused by protease-activated receptor-2 activation in human lung epithelial cells., XVIIth International Congress on Fibrinolysis and Proteolysis,   2004 03 , XVIIth International Congress on Fibrinolysis and Proteolysis
  • Roles of protease-activated receptor-1 and -2 in modulation of mouse gastrointestinal motility., XVIIth International Congress on Fibrinolysis and Proteolysis,   2004 03 , XVIIth International Congress on Fibrinolysis and Proteolysis
  • Mechanisms underlying contraction/relaxation caused by activation of protease-activated receptors 1 and 2 in rat superior mesenteric artery., XVIIth International Congress on Fibrinolysis and Proteolysis,   2004 03 , XVIIth International Congress on Fibrinolysis and Proteolysis
  • Pulmonary arterial pressure of WKY and SHRSP,   2000 07

Misc

  • Contraction of arterial smooth muscle of normotensive and spontaneously hypertensive rats by manganese(III)tetrakis(1-methyl-4-pyridyl)porphyrin (MnTMPyP), F Sekiguchi, M Seo, S Sunano, JOURNAL OF PHARMACOLOGICAL SCIENCES, 92, 2, 163, 165,   2003 06 , 10.1254/jphs.92.163
    Summary:Manganese(III)tetrakis(1-methyl-4-pyridyl)porphyrin (MnTMPyP), which has been known as a cell permeable superoxide dismutase mimetic, induced concentration-dependent contraction in rat carotid artery acting directly on smooth muscle. The contractile action was more prominent in the preparation from stroke-prone spontaneously hypertensive rats (SHRSP) compared with that from Wistar Kyoto rats (WKY). It was abolished by the removal of extracellular Ca2+ or the application of verapamil. These results suggest that the MnTMPyP-induced contraction is brought about by Ca2+ influx through voltage-dependent Ca2+ channels (VDCC) and that the difference in VDCC is the cause of the difference in MnTMPyP action between preparations from WKY and SHRSP.
  • Receptor-activating peptides for PAR-1 and PAR-2 relax rat gastric artery via multiple mechanisms, A Kawabata, Y Nakaya, T Ishiki, S Kubo, R Kuroda, F Sekiguchi, N Kawao, H Nishikawa, K Kawai, LIFE SCIENCES, 75, 22, 2689, 2702,   2004 10 , 10.1016/j.lfs.2004.07.006
    Summary:Receptor-activating peptides for protease-activated receptors (PARs) 1 or 2 enhance gastric mucosal blood flow 1 (GMBF) and protect against gastric mucosal injury in rats. We thus examined and characterized the effects of PARI and PAR-2 agonists on the isometric tension in isolated rat gastric artery. The agonists for PAR-2 or PAR-1 produced vasodilation in the endothelium-intact arterial rings, which was abolished by removal of the endothelium. The mechanisms underlying the PAR-2- and PAR-1-mediated relaxation involved NO, endothelium-derived hyperpolarizing factor (EDHF) and prostanoids, to distinct extent, as evaluated by use of inhibitors of NO synthase, cyclo-oxygenase and Ca2+-activated K+ channels. The EDHF-dependent relaxation responses were significantly attenuated by gap junction inhibitors. These findings demonstrate that endothelial PAR-1 and PAR-2, upon activation, dilate the gastric artery via NO and prostanoid formation and also EDHF mechanisms including gap junctions, which would enhance GMBF. (C) 2004 Elsevier Inc. All rights reserved.
  • Proteinase-activated receptor-2-mediated relaxation in mouse tracheal and bronchial smooth muscle: Signal transduction mechanisms and distinct agonist sensitivity, A Kawabata, S Kubo, T Ishiki, N Kawao, F Sekiguchi, R Kuroda, MD Hollenberg, T Kanke, N Saito, JOURNAL OF PHARMACOLOGY AND EXPERIMENTAL THERAPEUTICS, 311, 1, 402, 410,   2004 10 , 10.1124/jpet.104.068387
    Summary:We characterized the tracheal and bronchial relaxation caused by proteinase-activated receptor-2 (PAR-2) activation in ddY mice and/or in wild-type and PAR-2-knockout mice of C57BL/6 background. Ser-Leu-Ile-Gly-Arg-Leu-amide (SLIGRL-NH2) and Thr-Phe-Leu-Leu-Arg-amide, PAR-2- and PAR-1-activating peptides, respectively, caused relaxation in the isolated ddY mouse trachea and main bronchus. The relaxation was abolished by specific inhibitors of cyclooxygenase (COX)-1, COX-2, mitogen-activated protein kinase kinase (MEK), and p38 MAP kinase. The MEK and p38 MAP kinase inhibitors did not affect prostaglandin E-2-induced relaxation. Inhibitors of cytosolic Ca2+-dependent phospholipase A(2) (PLA(2)), Ca2+-independent PLA(2), diacylglycerol lipase, tyrosine kinase, and protein kinase C exhibited no or only minor inhibitory effects on the PAR-mediated relaxation. Trypsin, a PAR-2 activator, and 2-furoyl-Leu-Ile-Gly-Arg-Leu-amide, a potent PAR-2- activating peptide, in addition to SLIGRL-NH2, caused airway relaxation in wild-type C57BL/6 mice, as in ddY mice. In PAR-2-knockout mice, the peptide effects were absent and the potency of trypsin decreased. Desensitization of PAR-2 and/or PAR-1-greatly suppressed the relaxant effect of trypsin. The bronchial and tracheal tissues displayed distinct sensitivities toward trypsin and the PAR-2-activating peptides. Our data indicate an involvement of both COX-1 and COX-2, and the MEK-extracellular signal-regulated kinase and p38 MAP kinase signaling pathways in the PAR-2- and PAR-1-triggered relaxation of mouse airway tissue, and substantiate a role for PAR-2 in regulating both the trachea and bronchial responsiveness in the mouse lung.
  • Activation of trigeminal nociceptive neurons by parotid PAR-2 activation in rats, A Kawabata, H Itoh, N Kawao, R Kuroda, F Sekiguchi, T Masuko, K Iwata, A Ogawa, NEUROREPORT, 15, 10, 1617, 1621,   2004 07 , 10.1097/01.wnr.0000134991.97051.6b
    Summary:To clarify involvement of protease-activated receptor-2 (PAR-2) in parotid pain, we examined whether PAR-2 activation in the parotid gland could activate trigeminal nociceptive neurons in anesthetized rats, by analyzing immunoreactive Fos as a nociceptive marker. Either the PAR-2 agonist SLIGRL-NH2 or capsaicin, injected into the parotid duct, caused expression of Fos in the trigeminal subnucleus caudalis, although the PAR-2-inactive reversed peptide had no such effect. The Fos expression caused by PAR-2 activation was inhibited by ablation of capsaicin-sensitive sensory neurons. Intraductal SLIGRL-NH2 did not increase vascular permeability in the parotid gland. Our data thus reveal that activation of PAR-2 in the parotid gland can cause activation of trigeminal nociceptive neurons via capsaicin-sensitive sensory nerves most probably by a non-inflammatory mechanism.
  • The potent inducible nitric oxide synthase inhibitor ONO-1714 inhibits neuronal NOS and exerts antinociception in rats, F Sekiguchi, Y Mita, Y Kamanaka, N Kawao, H Matsuya, C Taga, A Kawabata, NEUROSCIENCE LETTERS, 365, 2, 111, 115,   2004 07 , 10.1016/j.neulet.2004.04.069
    Summary:We evaluated if ONO-1714, known as an inducible nitric oxide synthase (iNOS) inhibitor, could inhibit neuronal NOS (nNOS) and exert antinociception. ONO-1714 potently inhibited both crude rat cerebellar NOS and recombinant human nNOS in vitro. Systemic ONO-1714 at 1-10 mg/kg suppressed carrageenan-induced thermal hyperalgesia in rats, an effect being equivalent to the antinociception caused by L-NAME or 7-nitroindazole at 25 m/kg. The same doses of ONO-1714 also caused hypertension. Intrathecal (j.t.) ONO-1714 potently reduced the hyperalgesia. the effective dose range (0.2-0.6 mug/rat) being much lower than the antinociceptive dose (150 mug/rat) of i.t. L-NAME. Thus, ONO-1714 is considered a potent inhibitor of nNOS in addition to iNOS. The distinct relative antinociceptive activities of systemic and i.t. ONO-1714 are attributable to its possible poor blood-brain barrier permeability. (C) 2004 Elsevier Ireland Ltd. All rights reserved.
  • Potent and metabolically stable agonists for protease-activated receptor-2: Evaluation of activity in multiple assay systems in vitro and in vivo, A Kawabata, T Kanke, D Yonezawa, T Ishiki, M Saka, M Kabeya, F Sekiguchi, S Kubo, R Kuroda, M Iwaki, K Katsura, R Plevin, JOURNAL OF PHARMACOLOGY AND EXPERIMENTAL THERAPEUTICS, 309, 3, 1098, 1107,   2004 06 , 10.1124/jpet.103.061010
    Summary:To develop potent and metabolically stable agonists for protease-activated receptor-2 (PAR-2), we prepared 2-furoylated (2f) derivatives of native PAR-2-activating peptides, 2f-LIGKV-OH, 2f-LIGRL-OH, 2f-LIGKV-NH2, and 2f-LIGRL-NH2, and systematically evaluated their activity in PAR-2-responsive cell lines and tissues. In both HCT-15 cells and NCTC2544 cells overexpressing PAR-2, all furoylated peptides increased cytosolic Ca2+ levels with a greater potency than the corresponding native peptides, although a similar maximum response was recorded. The absolute potency of each peptide was greater in NCTC2544, possibly due to a higher level of receptor expression. Furthermore, the difference in potency between the 2-furoylated peptides and the native peptides was enhanced when evaluated in the rat superior mesenteric artery and further increased when measuring PAR-2-mediated salivation in ddY mice in vivo. The potency of 2f-LIGRL-NH2, the most powerful peptide, relative to SLIGKV-OH, was about 100 in the cultured cell Ca2+ signaling assays, 517 in the vasorelaxation assay, and 1100 in the salivation assay. Amastatin, an aminopeptidase inhibitor, augmented salivation caused by native peptides, but not furoylated peptides. The PAR-2-activating peptides, including the furoylated derivatives, also produced salivation in the wild-type C57BL/6 mice, but not the PAR-2-deficient mice. Our data thus demonstrate that substitution of the N-terminal serine with a furoyl group in native PAR-2-activating peptides dramatically enhances the agonistic activity and decreases degradation by aminopeptidase, leading to development of 2f-LIGRL-NH2, the most potent peptide. Furthermore, the data from PAR-2-deficient mice provide ultimate evidence for involvement of PAR-2 in salivation and the selective nature of the 2-furoylated peptides.
  • Distinct roles for protease-activated receptors 1 and 2 in vasomotor modulation in rat superior mesenteric artery, A Kawabata, S Kubo, Y Nakaya, T Ishiki, R Kuroda, F Sekiguchi, N Kawao, H Nishikawa, CARDIOVASCULAR RESEARCH, 61, 4, 683, 692,   2004 03 , 10.1016/j.cardiores.2003.11.030
    Summary:Objective: Protease-activated receptors (PARs) 1 and 2 are expressed in various blood vessels including rat aorta, modulating vascular tone. We investigated the roles of PAR-1 and PAR-2 in vasomotor modulation in rat superior mesenteric artery. Methods and results: Effects of the PAR-2-activating peptide Ser-Leu-Ile-Gly-Arg-Leu-amide (SLIGRL-amide) and the PAR-1-activating peptide Thr-Phe-Leu-Leu-Argamide (TFLLR-amide) on isometric tension were examined in isolated rat superior mesenteric artery or aorta. Both SLIGRL-amide and TFLLR-amide caused relaxation in the precontracted rat aortic rings. The latter peptide, but not the former, produced contraction in the resting rings. N-G-nitro-L-arginine methyl ester (L-NAME), but not apamin/charybdotoxin known to block the endothelium-derived hyperpolarizing factor (EDHF) pathway, abolished the relaxation and facilitated the contraction. In the precontracted rat superior mesenteric artery, SLIGRL-amide, but not TFLLR-amide, elicited endothelium-dependent relaxation, which was only partially inhibited by L-NAME with and without indomethacin. The residual relaxation was abolished by apamin/charybdotoxin. Carbenoxolone, a gap junction inhibitor, significantly attenuated the SLIGRL-amide-evoked, EDHF-dependent relaxation, although neither 17-octadecynoic acid, a P450 epoxygenase inhibitor, nor catalase, a hydrogen peroxide scavenger, revealed inhibitory effects. The residual response resistant to carbenoxolone was unaffected by ouabain/BaCl2. In the resting artery, TFLLR-amide, but not SLIGRL-amide, produced only slight contraction, which was dramatically facilitated by combination of L-NAME and apamin/charybdotoxin or by removal of the endothelium. Conclusions: Our data suggest that, in rat superior mesenteric artery, endothelial PAR-2, upon activation, causes relaxation via both NO and EDHF pathways, and that activation of muscular PAR-1 exhibits potential contractile activity that is largely masked by NO and EDHFs pathways triggered by endothelial PAR-1. Gap junctions might be involved in the EDHF mechanisms in this artery. (C) 2004 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.
  • Abnormal response to ryanodine in oesophageal striated muscle of spontaneously hypertensive rats, F Sekiguchi, K Kawata, M Yamazoe, S Sunano, EUROPEAN JOURNAL OF PHARMACOLOGY, 486, 1, 91, 98,   2004 02 , 10.1016/j.ejphar.2003.11.081
    Summary:The effects of ryanodine on twitch contraction and basal tension of oesophageal striated muscle were compared between preparations from stroke-prone spontaneously hypertensive rats (SHRSP) and normotensive Wistar Kyoto rats (WKY). Ryanodine (3 x 10(-7) M) augmented the twitch contraction in WKY preparations, butt attenuated it in SHRSP preparations. Rates of contraction and relaxation of twitch contraction, normalized to developed tension, were slightly decreased by ryanodine in both preparations. The effect of ryanodine was not different between WKY and SHRSP preparations. Ryanodine elevated the basal tension in WKY preparations but not in SHRSP preparations. Ryanodine elevated the intracellular Ca2+ level in both preparations, but the response was significantly less in SHRSP preparations. Resting and action potentials were not significantly different between WKY and SHRSP preparations, while the duration of the action potential was significantly longer in SHRSP preparations. Ryanodine did not alter the resting and action potentials of either preparation. These results suggest that the Ca2+ handling properties, including the ryanodine receptor, of the sarcoplasmic reticulum are genetically altered in oesophageal striated muscle of SHRSP. (C) 2003 Published by Elsevier B.V.
  • Protease-activated receptors (PARs) as therapeutic targets: development of agonists/antagonists and modulation of gastrointestinal functions., Drug Design Rev., in press,   2004
  • Superoxide dismutase reduces the impairment of endothelium-dependent relaxation in the spontaneously hypertensive rat aorta., J. Smooth Muscle Res., 40, 2, 65-74,   2004 , 10.1540/jsmr.40.65
  • Modulation of capsaicin-evoked visceral pain and referred hyperalgesia by protease-activated receptors 1 and 2., J. Pharmacol. Sci., 94, 3, 277-285,   2004 , 10.1254/jphs.94.277
  • A protective role of protease-activated receptor 1 in rat gastric mucosa, A Kawabata, H Nishikawa, H Saitoh, Y Nakaya, K Hiramatsu, S Kubo, M Nishida, N Kawao, R Kuroda, F Sekiguchi, M Kinoshita, K Kakehi, N Arizono, H Yamagishi, K Kawai, GASTROENTEROLOGY, 126, 1, 208, 219,   2004 01 , 10.1053/j.gastro.2003.10.071
    Summary:Background & Aims: On activation, protease-activated receptor (PAR)-2 modulates multiple gastric functions and exerts mucosal protection via activation of sensory neurons. The role of PAR-1, a thrombin receptor, in the stomach remains unknown. We thus examined if the PAR-1 agonist could protect against gastric mucosal injury in rats. Methods: Gastric mucosal injury was created by oral administration of ethanol/HCl or absolute ethanol in conscious rats. Gastric mucosal blood flow and acid secretion were determined in anesthetized rats. Immunohistochemical analyses of PAR-1 and cyclooxygenase (COX)-1 were also performed in rat and human stomach. Results: The PAR-1 agonist TFLLR-NH2, administered intravenously in combination with amastatin, protected against the gastric mucosal injury induced by ethanol/HCl or absolute ethanol. The protective effect of TFLLR-NH2 was abolished by indomethacin or a COX-1 inhibitor but not by ablation of sensory neurons with capsaicin. TFLLR-NH2 produced an NO-independent increase in gastric mucosal blood flow that was partially inhibited by blockade of the endothelium-derived hyperpolarizing factor pathway. This inhibitory effect was promoted by indomethacin. TFLLR-NH2 suppressed carbachol-evoked acid secretion in an indomethacin-reversible manner. Immunoreactive PAR-1 and COX-1 were expressed abundantly in rat gastric muscularis mucosae and smooth muscle, and the former protein was also detectable in blood vessels. Similar staining was observed in human gastric muscularis mucosae. Conclusions: The PAR-1. agonist, given systemically, protects against gastric mucosal injury via COX-1-dependent formation of prostanoids, modulating multiple gastric functions. Our data identify a novel protective role for PAR-1 in gastric mucosa, and the underlying mechanism is entirely different from that for PAR-2.
  • Effect of a potent iNOS inhibitor (ONO-1714) on acetaminophen-induced hepatotoxicity in the rat, Y Kamanaka, A Kawabata, H Matsuya, C Taga, F Sekiguchi, N Kawao, LIFE SCIENCES, 74, 6, 793, 802,   2003 12 , 10.1016/j.lfs.2003.09.036
    Summary:Overproduction of nitric oxide (NO) in the liver has been implicated as an important event in endotoxin shock and in other models of hepatic inflammation and injury. The present study was undertaken to evaluate the effect of ONO-1714, a potent and specific inhibitor of inducible NO synthase (iNOS), on acetaminophen-induced hepatotoxicity in the rats. Oral administration of ONO-1714 dose-dependently inhibited NOx (NO2 and NO3-) accumulation in rat plasma after lipopolysaccharide (LPS) treatment. Intraperitoneal acetaminophen at 1 g/kg caused damage to the centrilobular regions of the liver and increase in serum alanine and aspartate transaminase (ALT and AST, respectively) levels accompanied by elevated plasma NOx levels after 24 h. Oral administration of ONO-1714 at 10 and 100 mug/kg dose-dependently reduced the acetaminophen-induced hepatic tissue damage and the increases in serum ALT and AST levels. ONO-1714 also blocked the increase in plasma NOx concentrations. These findings demonstrate that oral ONO-1714, an iNOS inhibitor, protects against acetaminophen-evoked hepatic inflammation/injury, strongly suggesting that NO produced by iNOS plays a key role in the pathogenesis of this drug-induced hepatotoxicity. (C) 2003 Elsevier Inc. All rights reserved.
  • The PAR-1-activating peptide facilitates pepsinogen secretion in rats, N Kawao, K Hiramatsu, N Inoi, R Kuroda, H Nishikawa, F Sekiguchi, A Kawabata, PEPTIDES, 24, 9, 1449, 1451,   2003 09 , 10.1016/j.peptides.2003.08.010
    Summary:Protease-activated receptor-2 (PAR-2) is abundantly expressed in gastric mucosal chief cells, facilitating pepsinogen secretion. In the present study, we investigated whether PAR-1, a thrombin receptor, could modulate pepsinogen secretion in rats. The PAR-1-activating peptide TFLLR-NH2 as well as the PAR-2-activating peptide SLIGRL-NH2, administered i.v. repeatedly at 1-h intervals, significantly increased gastric pepsinogen secretion over 2-4 h (after two to four doses). In contrast, the control peptide FTLLR-NH2, given in the same manner, had no such effect. Thus, PAR-1, like PAR-2, might function to facilitate pepsinogen secretion, suggesting a novel role of the thrombin-PAR-1-pathway in the stomach. (C) 2003 Elsevier Inc. All rights reserved.
  • Contraction of arterial smooth muscle of normotensive and spontaneously hypertensive rats by manganese(III)tetrakis(1-methyl-4-pyridyl)porphyrin (MnTMPyP), F Sekiguchi, M Seo, S Sunano, JOURNAL OF PHARMACOLOGICAL SCIENCES, 92, 2, 163, 165,   2003 06 , 10.1254/jphs.92.163
    Summary:Manganese(III)tetrakis(1-methyl-4-pyridyl)porphyrin (MnTMPyP), which has been known as a cell permeable superoxide dismutase mimetic, induced concentration-dependent contraction in rat carotid artery acting directly on smooth muscle. The contractile action was more prominent in the preparation from stroke-prone spontaneously hypertensive rats (SHRSP) compared with that from Wistar Kyoto rats (WKY). It was abolished by the removal of extracellular Ca2+ or the application of verapamil. These results suggest that the MnTMPyP-induced contraction is brought about by Ca2+ influx through voltage-dependent Ca2+ channels (VDCC) and that the difference in VDCC is the cause of the difference in MnTMPyP action between preparations from WKY and SHRSP.
  • Caffeine-induced contracture in oesophageal striated muscle of normotensive and hypertensive rats, F Sekiguchi, K Kawata, M Komori, S Sunano, EUROPEAN JOURNAL OF PHARMACOLOGY, 465, 1-2, 153, 161,   2003 03 , 10.1016/S0014-2999(03)01435-3
    Summary:To elucidate whether properties of the sarcoplasmic reticulum are altered, not only in vascular smooth muscle, but also in visceral striated muscle of spontaneously hypertensive rats (SHR), caffeine-induced contractures in oesophageal striated muscle of Wistar Kyoto rats (WKY) and stroke-prone SHR (SHRSP) were compared. In both preparations, 30 mM caffeine induced a contracture with two components. The second component, which was diminished by extracellular Ca2+ removal or Ni2+ but not by verapamil, was much smaller in SHRSP. Both components and differences between WKY and SHRSP coincided with changes in intracellular Ca2+. Although membrane potential was identical between these preparations, caffeine induced slight depolarization only in WKY preparations. Similar depolarization was observed with 10 mM K+, which induced no contraction. It is suggested that the first and the second components of caffeine-induced contracture were induced by Ca2+ released from sarcoplasmic reticulum and by Ca2+ that entered through channels activated by sarcoplasmic reticulum Ca2+ depletion, respectively In SHRSP preparations, Ca2+ from the latter pathway was clearly decreased, although this change is thought not to be related to the initiation of hypertension. These results suggest that Ca2+ handling properties of cell membrane and sarcoplasmic reticulum are generally altered in muscles of SHRSP. (C) 2003 Elsevier Science B.V. All rights reserved.
  • Caffeine-induced contracture in oesophageal striated muscle of normotensive and hypertensive rats, F Sekiguchi, K Kawata, M Komori, S Sunano, EUROPEAN JOURNAL OF PHARMACOLOGY, 465, 1-2, 153, 161,   2003 03 , 10.1016/S0014-2999(03)01435-3
    Summary:To elucidate whether properties of the sarcoplasmic reticulum are altered, not only in vascular smooth muscle, but also in visceral striated muscle of spontaneously hypertensive rats (SHR), caffeine-induced contractures in oesophageal striated muscle of Wistar Kyoto rats (WKY) and stroke-prone SHR (SHRSP) were compared. In both preparations, 30 mM caffeine induced a contracture with two components. The second component, which was diminished by extracellular Ca2+ removal or Ni2+ but not by verapamil, was much smaller in SHRSP. Both components and differences between WKY and SHRSP coincided with changes in intracellular Ca2+. Although membrane potential was identical between these preparations, caffeine induced slight depolarization only in WKY preparations. Similar depolarization was observed with 10 mM K+, which induced no contraction. It is suggested that the first and the second components of caffeine-induced contracture were induced by Ca2+ released from sarcoplasmic reticulum and by Ca2+ that entered through channels activated by sarcoplasmic reticulum Ca2+ depletion, respectively In SHRSP preparations, Ca2+ from the latter pathway was clearly decreased, although this change is thought not to be related to the initiation of hypertension. These results suggest that Ca2+ handling properties of cell membrane and sarcoplasmic reticulum are generally altered in muscles of SHRSP. (C) 2003 Elsevier Science B.V. All rights reserved.
  • Effects of L-arginine on spontaneous of the rat portal vein, Pflügers Atchievs, 446, 30, 35,   2003
  • Reduced effect of caffeine on twitch contraction of esophageal striated muscle from SHRSP (共著), Clinical and Experimental Pharmacology and Physiology, 30, 223, 231,   2003 , 10.1046/j.1440-1681.2003.03819.x
  • Endothelium-dependent relaxation in pulmonary arteries of L-NAME-treated Wistar and stroke-prone spontaneously hypertensive rats(共著), Journal of Smooth Muscle Research, 38(4,5), 131-144,   2002 , 10.1540/jsmr.38.131
  • Responses to endothelium-derived factors and their interaction in mesenteric arteries from Wistar-Kyoto and stroke-prone spontaneously hypertensive rats(共著), Clinical and Experimental Pharmacology and Physiology, 29, 1066-1075,   2002 , 10.1046/j.1440-1681.2002.03778.x
  • Unaltered caffeine-induced relaxation in the aorta of stroke-prone spontaneously hypertensive rats (共著), Journal of Smooth Muscle Research, 38(1,2), 11-22,   2002 , 10.1540/jsmr.38.11
  • Effects of flufenamic acid on smooth muscle of the carotid artery isolated from spontaneously hypertensive rats(共著), Journal of Smooth Muscle Research, 38(1,2), 39-50,   2002 , 10.1540/jsmr.38.39
  • Effects of NG-nitro-L-arginine on the blood pressure of spontaneously hypertensive rats with different degrees of hypertension(共著), Clinical and Experimental Hypertension, 23(7), 533-544,   2001 , 10.1081/CEH-100106824
  • Rhythmic spontaneous contractions in the rat proximal colon(共著), Japanese Journal of Physiology, 51, 717-723,   2001 , 10.2170/jjphysiol.51.717
  • Hypertension and impairment of endothelium-dependent relaxation of arteries from spontaneously hypertensive and L-NAME-treated Wistar rats(共著), Journal of Smooth Muscle Research, 37(2), 67-79,   2001 , 10.1540/jsmr.37.67
  • Factors involved in the time course of response to acetylcholine in mesenteric arteries from spontaneously hypertensive rats(共著), European Journal of Pharmacology,   2001 , 10.1016/S0014-2999(01)01081-0
  • Role of nitric oxide in the contraction of circular muscle in the rat portal vein, K Shimamura, LB Zou, K Matsuda, F Sekiguchi, K Yamamoto, S Sunano, PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY, 440, 3, 435, 439,   2000 07
    Summary:The role of nitric oxide in the electrical and mechanical activities of the rat portal vein was examined in circular muscle preparations with intact endothelium that were isolated from the longitudinal muscle layer. In contrast to the longitudinal muscle preparation, the circular muscle preparation did not show spontaneous phasic contraction. Inhibition of nitric oxide synthesis by N-omega-nitro-L-arginine (L-NNA) induced a tonic contraction. The contraction was inhibited by L-arginine, sodium nitroprusside or nifedipine. L-NNA did not induce contraction in endothelium-damaged preparations. The membrane potential of smooth muscle cells recorded in endothelium-intact preparations showed sporadic action potentials. L-NNA increased the frequency of action potentials without changing the resting membrane potential. The action potentials were inhibited by nifedipine. In the presence of L-NNA, sodium nitroprusside decreased the frequency of the action potentials without changing the resting membrane potential. These results indicated that contraction of rat portal vein circular muscles is inhibited tonically by nitric oxide, at least partly through inhibition of electrical activity.
  • Isoproterenol-induced relaxation in stomach smooth muscle of rats and its abnormality in hypertensive rats.(共著), Journal of Muscle Research and Cell Motility, 21, 3, 201,   2000
  • Difference in effects of stretch on depressive effect of endothelium-derived nitric oxide on noradrenaline-and high-K+-induced contractions between the aortae from normotensive and spontaneously hypertensive rats.(共著), Fumiko SEKIGUCHI, Yoshimasa MIYAKE, Shihoko NAKAZUMI, Keiichi SHIMAMURA, Kazuo YAMAMOTO, Satoru SUNANO, Journal of Smooth Muscle Research, 37, 1, 9, 23,   2000 , 10.1540/jsmr.37.9
  • Transmural field stimulation-induced relaxation in the rat common hepatic artery.(共著), Keiichi SHIMAMURA, Kazuo YAMAMOTO, Fumiko SEKIGUCHI, Satoru SUNANO, Shinichi KIMURA, Hideya SAITO, Journal of Smooth Muscle Research, 36, 4, 137, 144,   2000 , 10.1540/jsmr.36.137
  • Arterial smooth muscle tone and its modification by endothelium in spontaneously hypertensive rats (共著), Biomedical Research, 11, 2, 137, 147,   2000
  • Altered β-adrenoceptor-mediated responses in the gastric smooth muscle of hypertensive rats (共著), Keiichi SHIMAMURA, Kazuo YAMAMOTO, Fumiko SEKIGUCHI, Satoru SUNANO, Journal of Smooth Muscle Research, 36, 1, 1, 12,   2000 , 10.1540/jsmr.36.1
  • Effect of chronic treatment with perindopril on endothelium-dependent relaxation of aorta and carotid artery in SHRSP (共著), Keiichi SHIMAMURA, Fumiko SEKIGUCHI, Kyoko MATSUDA, Mirei OZAKI, Kiyomi NOGUCHI, Kazuo YAMAMOTO, Toshiro SHIBANO, Makoto TANAKA, Satoru SUNANO, Journal of Smooth Muscle Research, 36, 1, 33, 46,   2000 , 10.1540/jsmr.36.33
  • Unaltered endothelium-dependent modulation of contraction in the pulmonary artery of hypertensive rats (共著), European Journal of Pharmacology, 392, 1/2, 61, 70,   2000 , 10.1016/S0014-2999(00)00073-X
  • Involvement of endothelium-derived factors in controlling the active tone of smooth muscle in aorta from hypertensive rats (共著), 8, 79, 89,   1999
  • Effects of cyclopiazonic acid on contraction and intracellular Ca2+in oesophageal striated muscle of normotensive and spontaneously hypertensive rats (共著), British Journal of Pharmacology, 128, 5, 961, 968,   1999 , 10.1038/sj.bjp.0702867
  • Tension oscillation in arteries and its abnormality in hypertensive animals(共著), Clinical and Experimental Pharmacology and Physiology, 26, 4, 275, 284,   1999 , 10.1046/j.1440-1681.1999.03030.x
  • Endothelium-derived relaxing, contracting and hyperpolarizing factors of mesenteric arteries of hypertensive and normotensive rats. (共著), British Journal of Pharmacology, 126, 3, 709, 716,   1999 , 10.1038/sj.bjp.0702355
  • Extracellular Ca2+-dependent contraction by Ca2+ pump inhibition in oesophageal striated muscle of normotensive and hypertensive rats, F Sekiguchi, K Shimamura, S Sunano, JOURNAL OF MUSCLE RESEARCH AND CELL MOTILITY, 19, 4, 449, 450,   1998 05
  • Membrane potential of mesenteric artery from carvedilol-treated spontaneously hypertensive rats, K Shimamura, F Sekiguchi, K Matsuda, K Yamamoto, S Tanaka, S Sunano, T Shibutani, H Hashimoto, M Tanaka, EUROPEAN JOURNAL OF PHARMACOLOGY, 344, 2-3, 161, 168,   1998 03 , 10.1016/S0014-2999(97)01573-2
    Summary:The effects of chronic treatment of stroke-prone spontaneously hypertensive rats (SHRSP) with carvedilol. an antihypertensive agent which has both alpha- and beta-adrenoceptor-blocking actions, on membrane potential and relaxation of mesenteric resistant artery were studied. Five-week old SHRSP were treated with carvedilol for three months. At 16 weeks, the resting membrane potential of arteries from carvedilol-treated SHRSP was more negative than that of arteries from untreated SHRSP. The magnitude of acetylcholine-induced hyperpolarization in arteries from carvedilol-treated SHRSP was not different from that of arteries from untreated SHRSP. In the presence of noradrenaline, the membrane potential of arteries from carvedilol-treated SHRSP was more negative than that of arteries from untreated SHRSP. The membrane potential of arteries from carvedilol-treated SHRSP in the presence of noradrenaline and acetylcholine Rns more negative than that of arteries from untreated SHRSP. The acetylcholine-induced relaxation in noradrenaline-precontracted preparations from carvedilol-treated SHRSP was greater than that in preparations from untreated SHRSP and was smaller than that in preparation from Wistar Kyoto rats. Scanning electronmicroscopy showed that carvedilol-treatment decreased the structural abnormali ties; of the endothelium of arteries from SHRSP. These results indicate that chronic carvedilol treatment made the membrane potential of smooth muscle more negative and improved endothelial function in the mesenteric artery of SHRSP, which may contribute to the antihypertensive effect of carvedilol. (C) 1998 Elsevier Science B.V.
  • Influences of endothelium on the time course of noradrenaline-, 5-HT-, prostaglandin F-and high-K2-induced contractions in aortae of WKY and SHRSP(共著), Journal of Smooth Muscle Research, 34, 5/6, 207, 219,   1998 , 10.1540/jsmr.34.207
  • Involvement of endothelium-derived factors in controlling active tone of smooth muscle in aorta from hypertensive rats(共著), Journal of Smooth Muscle Research, 34, 5/6, 221, 232,   1998 , 10.1540/jsmr.34.221
  • Ca2+-sensitivity of portal vein circular muslce from normotensive and hypertensive rats. (共著), Journal of Smooth Muslce Research, 34, 1, 23, 34,   1998 , 10.1540/jsmr.34.23
  • Effects of chronic treatment with carvedilol on smooth muscle tone and entothelium-dependent relaxation of aorta in stroke-prone spontaneously hypertensive rats(共著), Journal of Smooth Muscle Research, 33, 1, 23, 35,   1997 , 10.1540/jsmr.33.23
  • Comparison of reaction in the preparations of esophageal striated muscle from hypertensive and normotensive rats, 6, 29, 36,   1997
  • Hyperpolarization and relaxation mediated by endothelium-derived factors and abnormalities in hypertensive animals, J. Smooth Muscle Res. (Japanese Section), 1, 3, J-101-J-116,   1997 , 10.1540/heikatsukinzashi1997.1.J101
  • Role of endothelial cells in hypertension,   1997
  • Effects of amiloride on the neurally mediated contraction of rat mesenteric artery, Eur. J. Pharmacol., 320, 1, 37, 42,   1997 , 10.1016/S0014-2999(96)00879-5
  • Attenuation of intrinsic active tone by endothelium-derived nitric oxide in aortae of spontaneously hypertensive rats with different levels of blood pressure, S Sunano, F Sekiguchi, K Takeuchi, S Shibutani, K Matsuda, K Shimamura, CLINICAL AND EXPERIMENTAL HYPERTENSION, 18, 6, 873, 890,   1996 08 , 10.3109/10641969609081785
    Summary:The influences of endothelium on the basal tone of aortae from various strains of spontaneously hypertensive rats with different blood pressure (SHR, SHRSP, M-SHRSP) were studied. Endothelium-intact preparations of aortae from spontaneously hypertensive rats exhibited spontaneous active tone, which was greater in the order of SHR < SHRSP < M-SHRSP. The active tone of the M-SHRSP preparations was about 40% of high-K+-induced contraction, while that of normotensive WKY was less than 5%. The active tone was enhanced by the removal of endothelium. The active tone was sensitive to extracellular Ca2+ and abolished by verapamil. The application of N-G-monomethyl-L-arginine caused the increase in the active tone which was counteracted by L-arginine. These results indicate that the active tone of smooth muscle increases as the blood pressure of the rat increases, and that endothelium attenuates the active tone by releasing nitric oxide (NO) spontaneously. It was also demonstrated that the attenuating action of endothelium was impaired depending on the blood pressure level.
  • Endothelium-dependent relaxation by α2-adrenoceptor agonist in spontaneously hypertensive rat arots. (共著), Journal of Cardiovascular Pharmacology, 27, 5, 733, 739,   1996 , 10.1097/00005344-199605000-00017
  • Blood pressure and ag-dependent changes of endothelium-dependent tension oscilltion in diffrent strains of spontaneously hypertensiverats (共著), Journal of Smooth Muscle Research, 32, 2、145-154,   1996 , 10.1540/jsmr.32.145
  • Spontaneous and agoist-induced contractions and endothelium-dependent relaxation in aortae from SHASP and WKY rats under various levels passive force (共著), Clinical and Experimental Pharmacology and Physiology, 23、483-489,   1996
  • effects of cyclopiazonic acid and thapsigargin on electromechanical activities andCa2+ in smooth muscle of carotid artery of hypertensiverats (共著), British Journal of Pharcology, 118、857-864,   1996 , 10.1111/j.1476-5381.1996.tb15478.x
  • Effects of NG-nitro-L arginine on α-agonists-induced contraction of aortae from Wistar Kyoto rats and stroke-prone spontaneously hypertensive rats (共著), Journal of Smooth Muscle Research, 31, 2, 51, 60,   1995 , 10.1540/jsmr.31.51
  • Comparison of endothflium-dependent and -independent tentoin oscillation aortae of stroke-prone sponteneously hypertensive rats and Wistar kyoto rats (共著), Journal of Smooth Muscle Research, 30、135-145,   1994 , 10.1540/jsmr.30.135
  • Roles of extra- and intracellular Ca in aortic smooth muscle tone of spontaneously hypertensive rats (共著), Journal of Muscle Research and Cell Motility, 14, 3, 373,   1994
  • Ca2+-dependent active tone and blood pressure in various spontaneously hypertensive rats (共著), Journal of Muscle Research and Cell Motility, 15, 3, 362,   1994
  • Relationship between blood pressure and smooth muscle tone in aorta of hypertensive rat : roles of [Ca++] (共著), Fumiko SASAKI, S. OSUGI, K. SHIMAMURA, S. SUNANO, J. Smooth Muscle Research, 29, 3, 69, 79,   1993 , 10.1540/jsmr.29.69
  • Effects of endothelium- and smooth muscle-derived nitric oxide and arachidonic acid metabolites on norepinephrine-induced contraction of rat aorta (共著), Alpha-Adrenoceptor, 254-257,   1992
  • Sopntaneous tone and membrene potenitial in the aortic smooth muscle from hypertensive rats (共著), med.J.Kinki Univ., 20, 2、29-31

Research Grants & Projects

  • Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Study on the role of nuclear protein HMGB1 in the process of neurite regeneration after nerve injury
  • Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Study on the physiological role of endogenous hydrogen sulfide in the stomach with mucosal injury
  • Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Involvement of T-type calcium channels and calcineurin in the inflammatory and neuropathic pain
  • Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Effects of Helicobacter pylori on expression levels and function of proteinase-activated receptors in the gastric mucosal epithelial cells
  • Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Study on mechanisms for modulation of gastrointestinal motility by G-protein-coupled proteinase-activated receptors
  • Tone and intercellular Ca in the vascular smooth muscle of hypertensive rats
  • Study on physiological and pathophysilogical roles of protease-activated receptor.