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FUNAKAMI Yoshinori

    Department of Pharmacy　Associate Professor
Last Updated :2024/04/17

Researcher Information

URL

J-Global ID

Research Interests

  • 自律神経   視床下部   神経活性   血管反応性   ストレス   慢性ストレス   c-Fos   Head-up tilt試験   急性ストレス   起立性低血圧   低血圧   血管収縮反応   

Research Areas

  • Life sciences / Internal medicine - General

Academic & Professional Experience

  • 2020/04  近畿大学薬学部准教授
  • 2011  Kindai UniversityFaculty of PharmacyLecturer

Published Papers

  • Hikari Nishisaka; Takumi Tomohiro; Kako Fukuzumi; Akira Fukao; Yoshinori Funakami; Toshinobu Fujiwara
    Biochimie 221 20 - 26 2024/01 
    The RNA-binding protein HuD/ELAVL4 is essential for neuronal development and synaptic plasticity by governing various post-transcriptional processes of target mRNAs, including stability, translation, and localization. We previously showed that the linker region and poly(A)-binding domain of HuD play a pivotal role in promoting translation and inducing neurite outgrowth. In addition, we found that HuD interacts exclusively with the active form of Akt1, through the linker region. Although this interaction is essential for neurite outgrowth, HuD is not a substrate for Akt1, raising questions about the dynamics between HuD-mediated translational stimulation and its association with active Akt1. Here, we demonstrate that active Akt1 interacts with the cap-binding complex via HuD. We identify key amino acids in linker region of HuD responsible for Akt1 interaction, leading to the generation of two point-mutated HuD variants: one that is incapable of binding to Akt1 and another that can interact with Akt1 regardless of its phosphorylation status. In vitro translation assays using these mutants reveal that HuD-mediated translation stimulation is independent of its binding to Akt1. In addition, it is evident that the interaction between HuD and active Akt1 is essential for HuD-induced neurite outgrowth, whereas a HuD mutant capable of binding to any form of Akt1 leads to aberrant neurite development. Collectively, our results revisit the understanding of the HuD-Akt1 interaction in translation and suggest that this interaction contributes to HuD-mediated neurite outgrowth via a unique molecular mechanism distinct from translation regulation.
  • Hikari Nishisaka; Takumi Tomohiro; Akira Fukao; Yoshinori Funakami; Toshinobu Fujiwara
    Biological & pharmaceutical bulletin 46 (2) 158 - 162 2023 [Refereed]
     
    Translation initiation is the rate-limiting step of protein synthesis and is the main target of translation regulation. RNA-binding proteins (RBPs) are key mediators of the spatiotemporal control of translation and are critical for cell proliferation, development, and differentiation. We have previously shown that HuD, one of the neuronal RBPs, enhances cap-dependent translation through the direct interaction with eukaryotic initiation factor 4A (eIF4A) and poly(A) tail using a HeLa-derived in vitro translation system. We have also found that translation stimulation of HuD is essential for HuD-induced neurite outgrowth in PC12 cells. However, it remains unclear how HuD is involved in the regulation of translation initiation. Here, we report that HuD binds to eukaryotic initiation factor 3 (eIF3) via the eIF3b subunit, which belongs to the functional core of mammalian eIF3. eIF3 plays an essential role in recruiting the 40S ribosomal subunit onto mRNA in translation initiation. We hypothesize that the interaction between HuD and eIF3 stabilizes the translation initiation complex and increases translation efficiency. We also showed that the linker region of HuD is required for the interaction with eIF3b. Moreover, we found that eIF3b-binding region of HuD is conserved in all Hu proteins (HuB, HuC, HuD, and HuR). These data might also help to explain how Hu proteins stimulate translation in a cap- and poly(A)-dependent way.
  • Hiroshi Otsuka; Akira Fukao; Yoshinori Funakami; Kent E Duncan; Toshinobu Fujiwara
    Frontiers in genetics 12 715196 - 715196 2021 [Refereed]
     
    [This corrects the article DOI: 10.3389/fgene.2019.00332.].
  • Hiroshi Otsuka; Akira Fukao; Takumi Tomohiro; Shungo Adachi; Toru Suzuki; Akinori Takahashi; Yoshinori Funakami; Toru Natsume; Tadashi Yamamoto; Kent E Duncan; Toshinobu Fujiwara
    Biochimie 174 49 - 56 2020/04 [Refereed]
     
    Eukaryotic gene expression can be spatiotemporally tuned at the post-transcriptional level by cis-regulatory elements in mRNA sequences. An important example is the AU-rich element (ARE), which induces mRNA destabilization in a variety of biological contexts in mammals and can also mediate translational control. Regulation is mediated by trans-acting factors that recognize the ARE, such as Tristetraprolin (TTP) and BRF1/ZFP36L1. Although both proteins can destabilize their target mRNAs through the recruitment of the CCR4-NOT deadenylation complex, TTP also directly regulates translation. Whether ZFP36L1 can directly repress translation remains unknown. Here, we used an in vitro translation system derived from mammalian cell lines to address this key mechanistic issue in ARE regulation by ZFP36L1. Functional assays with mutant proteins reveal that ZFP36L1 can repress translation via AU-Rich elements independent of deadenylation. ZFP36L1-mediated translation repression requires interaction between ZFP36L1 and CNOT1, suggesting that it might use a repression mechanism similar to either TPP or miRISC. However, several lines of evidence suggest that the similarity ends there. Unlike, TTP, it does not efficiently interact with either 4E-HP or GIGYF2, suggesting it does not repress translation by recruiting these proteins to the mRNA cap. Moreover, ZFP36L1 could not repress ECMV-IRES driven translation and was resistant to pharmacological eIF4A inhibitor silvestrol, suggesting fundamental differences with miRISC repression via eIF4A. Collectively, our results reveal that ZFP36L1 represses translation directly and suggest that it does so via a novel mechanism distinct from other translational regulators that interact with the CCR4-NOT deadenylase complex.
  • Otsuka H; Fukao A; Funakami Y; Duncan KE; Fujiwara T
    Frontiers in genetics 10 332 - 332 2019 [Refereed]
     
    RNA-binding proteins (RBPs) are key regulators of posttranscriptional gene expression and control many important biological processes including cell proliferation, development, and differentiation. RBPs bind specific motifs in their target mRNAs and regulate mRNA fate at many steps. The AU-rich element (ARE) is one of the major cis-regulatory elements in the 3' untranslated region (UTR) of labile mRNAs. Many of these encode factors requiring very tight regulation, such as inflammatory cytokines and growth factors. Disruption in the control of these factors' expression can cause autoimmune diseases, developmental disorders, or cancers. Therefore, these mRNAs are strictly regulated by various RBPs, particularly ARE-binding proteins (ARE-BPs). To regulate mRNA metabolism, ARE-BPs bind target mRNAs and affect some factors on mRNAs directly, or recruit effectors, such as mRNA decay machinery and protein kinases to target mRNAs. Importantly, some ARE-BPs have stabilizing roles, whereas others are destabilizing, and ARE-BPs appear to compete with each other when binding to target mRNAs. The function of specific ARE-BPs is modulated by posttranslational modifications (PTMs) including methylation and phosphorylation, thereby providing a means for cellular signaling pathways to regulate stability of specific target mRNAs. In this review, we summarize recent studies which have revealed detailed molecular mechanisms of ARE-BP-mediated regulation of gene expression and also report on the importance of ARE-BP function in specific physiological contexts and how this relates to disease. We also propose an mRNP regulatory network based on competition between stabilizing ARE-BPs and destabilizing ARE-BPs.
  • Akitoshi Sadahiro; Akira Fukao; Mio Kosaka; Yoshinori Funakami; Naoki Takizawa; Osamu Takeuchi; Kent E. Duncan; Toshinobu Fujiwara
    Frontiers in Genetics 9 (AUG) 307  2018/08 [Refereed]
     
    © 2018 Sadahiro, Fukao, Kosaka, Funakami, Takizawa, Takeuchi, Duncan and Fujiwara. Many viruses strongly prefer to infect certain cell types, a phenomenon known as "tropism." Understanding tropism's molecular basis is important for the design of vaccines and antiviral therapy. A common mechanism involves viral protein interactions with cell-specific surface receptors, but intracellular mechanisms involving translation have also been described. In this report, we focus on Hepatitis A Virus (HAV) tissue tropism from the standpoint of the translational machinery. HAV genomic RNA, like other positive stranded RNA viruses, is devoid of a cap structure and its translation is driven by highly structured RNA sequences termed internal ribosome entry site (IRES) in the 5' untranslated region (UTR). Unlike most viral IRESs, HAV IRES-mediated translation requires eIF4E and the 3' end of HAV RNA is polyadenylated. However, the molecular mechanism of HAV IRES-mediated translation initiation remains poorly understood. We analyzed HAV-IRES-mediated translation in a cell-free system derived from either non-hepatic cells (HeLa) or hepatoma cells (Huh-7) that enables investigation of the contribution of the cap and the poly(A) tail. This revealed that HAV IRES-mediated translation activity in hepatoma cell extracts is higher as compared to extracts derived from a non-hepatic line. Our data suggest that HAV IRES-mediated translation is upregulated by a hepatic cell-specific activator in a poly(A) tail-independent manner.
  • Maho Tsubota; Tomoyoshi Miyamoto; Saki Hiruma; Haruka Saeki; Takaya Miyazaki; Fumiko Sekiguchi; Yoshinori Funakami; Atsufumi Kawabata
    PHARMACOLOGY KARGER 99 (5-6) 286 - 290 0031-7012 2017 [Refereed]
     
    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
  • Tomoyoshi Miyamoto; Yoshinori Funakami; Erika Kawashita; Ai Nomura; Nanako Sugimoto; Haruka Saeki; Maho Tsubota; Seiji Ichida; Atsufumi Kawabata
    BIOLOGICAL & PHARMACEUTICAL BULLETIN PHARMACEUTICAL SOC JAPAN 40 (1) 11 - 16 0918-6158 2017/01 [Refereed]
     
    The rodents exposed to repeated cold stress according to a specific schedule, known as specific alternation of rhythm in temperature (SART), exhibit autonomic imbalance, and is now used as an experimental model of fibromyalgia. To explore the susceptibility of SART-stressed animals to novel acute stress, we tested whether exposure of mice to SART stress for 1 week alters the extent of acute restraint stress-induced hyperthermia. Mice were subjected to 7-d SART stress sessions; i.e., the mice were alternately exposed to 24 and 4 degrees C at 1-h intervals during the daytime (09:00-16:00) and kept at 4 degrees C overnight (16:00-09:00). SART-stressed and unstressed mice were exposed to acute restraint stress for 20-60 min, during which rectal temperature was monitored. Serum corticosterone levels were measured before and after 60-min exposure to restraint stress. SART stress itself did not alter the body temperature or serum corticosterone levels in mice. Acute restraint stress increased the body temperature and serum corticosterone levels, both responses being greater in SART-stressed mice than unstressed mice. The enhanced hyperthermic responses to acute restraint stress in SART-stressed mice were significantly attenuated by SR59230A, a beta(3) adrenoceptor antagonist, but unaffected by diazepam, an anxiolytic, mifepristone, a glucocorticoid receptor antagonist, or indomethacin, a cyclooxygenase inhibitor. These results suggest that SART stress enhances the susceptibility of mice to acute restraint stress, characterized by increased hyperthermia and corticosterone secretion, and that the increased hyperthermic responses to acute stress might involve accelerated activation of sympathetic beta(3) adrenoceptors, known to regulate non-shivering thermogenesis in the brown adipose tissue.
  • Tomoyoshi Miyamoto; Yoshinori Funakami; Erika Kawashita; Shiori Tomita; Ai Nomura; Nanako Sugimoto; Haruka Saeki; Takaya Miyazaki; Maho Tsubota; Seiji Ichida; Atsufumi Kawabata
    PHARMACOLOGY KARGER 99 (3-4) 172 - 178 0031-7012 2017 [Refereed]
     
    Lipopolysaccharide (LPS) induces hyperthermia accompanied by various other systemic inflammatory symptoms. The rodents exposed to repeated cold (RC) stress according to a specific schedule are useful as experimental models for autonomic imbalance or fibromyalgia. It is now proven that RC-stressed mice exhibit tolerance to LPS, we examined thermal responses to LPS challenge in RC-stressed mice by monitoring core temperature using the telemetry system. Systemic administration of LPS caused bimodal hyperthermic responses in RC-stressed and unstressed mice. The magnitude of the LPS-induced hyperthermia was greater in RC-stressed mice than in unstressed mice. The RC stress-induced enhancement of hyperthermic responses to LPS was abolished by pretreatment with diclofenac, which is a cyclooxygenase (COX) inhibitor. LPS did not significantly increase COX-2 protein levels in the lung or hypothalamus of RC-stressed or unstressed mice. RC stress did not alter baseline serum corticosterone levels or their increases in response to LPS challenge. These results suggest that RC stress enhances the susceptibility of mice to LPS challenge, leading to greater prostanoid-dependent hyperthermia, which might contribute to tolerance to LPS in RC-stressed mice. (C) 2016 S. Karger AG, Basel.
  • Noriaki Nagai; Chiaki Yoshioka; Yoshimasa Ito; Yoshinori Funakami; Hiroyuki Nishikawa; Atsufumi Kawabata
    INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES MDPI AG 16 (12) 29329 - 29344 1422-0067 2015/12 [Refereed]
     
    It was reported that cilostazol (CLZ) suppressed disruption of the microvasculature in ischemic areas. In this study, we have designed novel injection formulations containing CLZ nanoparticles using 0.5% methylcellulose, 0.2% docusate sodium salt, and mill methods (CLZ(nano) dispersion; particle size 81 +/- 59 nm, mean +/- S.D.), and investigated their toxicity and usefulness in a cerebral ischemia/reperfusion-induced injury model (MCAO/reperfusion mice). The pharmacokinetics of injections of CLZ(nano) dispersions is similar to that of CLZ solutions prepared with 2-hydroxypropyl--cyclodextrin, and no changes in the rate of hemolysis of rabbit red blood cells, a model of cell injury, were observed with CLZ(nano) dispersions. In addition, the intravenous injection of 0.6 mg/kg CLZ(nano) dispersions does not affect the blood pressure and blood flow, and the 0.6 mg/kg CLZ(nano) dispersions ameliorate neurological deficits and ischemic stroke in MCAO/reperfusion mice. It is possible that the CLZ(nano) dispersions will provide effective therapy for ischemic stroke patients, and that injection preparations of lipophilic drugs containing drug nanoparticles expand their therapeutic usage.
  • Tadatoshi Tanino; Noriaki Nagai; Yoshinori Funakami
    JOURNAL OF PHARMACY AND PHARMACOLOGY WILEY 67 (10) 1457 - 1465 0022-3573 2015/10 [Refereed]
     
    ObjectivesThe objective of this study was to address the beneficial effects of Cistanche tubulosa extract on improving the low intestinal permeability of echinacoside (ECH) and acteoside (ACT).MethodsAbsorption of ECH and ACT in C.tubulosa extract was characterized using human intestinal Caco-2 cell monolayers with intact compounds. Glucose transporter-dependent absorption of ECH and ACT was confirmed by an in-situ intestinal perfusion technique.Key findingsThe apparent permeability (P-app) was not significantly different between intact ECH and intact ACT. In the presence of phloridzin, the P-app of the ECH and ACT at a high dose was reduced to 20% of the respective non-treatment, but was not altered by phloretin and verapamil. C.tubulosa extract at low and high doses enhanced the P-app of ECH and ACT (both by threefold), resulting in their large participation in sodium-dependent glucose transporter-independent absorption. At a low concentration, concomitant ECH and ACT levels in portal blood were significantly suppressed by phloridzin.ConclusionThe dietary and medicinal C.tubulosa extract enhancing the intestinal absorption of ECH and ACT may serve to better manage human health, although the involvement of phloridzin-sensitive transport should be reduced.
  • Tadatoshi Tanino; Yoshinori Funakami; Noriaki Nagai; Yoshihisa Kato
    JOURNAL OF PHARMACY AND PHARMACOLOGY WILEY-BLACKWELL 67 (10) 1406 - 1415 0022-3573 2015/10 [Refereed]
     
    Objectives2-Arylpropionic acid (profen) drugs are associated with severe hepatotoxicity; however, risk factors are still poorly understood. Acyl-coenzyme A (acyl-CoA) thioesters of profen drugs play a more important role in the covalent binding to rat hepatocyte proteins than the respective acyl-glucuronides. Therefore, we examined whether acyl-glucuronides, acyl-CoA thioesters and oxidative metabolites of profen drugs stereoselectively participated in liver damage.MethodsCytotoxicity was determined by measuring lactate dehydrogenase (LDH) leakage from three-dimensional cultured rat hepatocytes.Key findingsLDH leakage was not induced by R-2-phenylpropionic acid and R-ibuprofen greatly forming acyl-CoA thioesters. S-Naproxen metabolized mainly by Uridine 5-diphosphate (UDP)-glucuronosyl-transferase did not enhance LDH leakage. However, flurbiprofen (FLP) induced LDH leakage. A selective cytochrome P450 (CYP) 2C11 inhibitor suppressed 40-50% of the R-FLP and S-FLP-induced cytotoxicity. Borneol non-stereoselectively accelerated the FLP-induced cytotoxicity. The R-FLP-induced cytotoxicity decreased intracellular adenosine triphosphate (ATP) levels to 50% of untreated hepatocytes. An inhibitor of mitochondrial permeability transition pore, cyclosporin A (Cys A), rescued ATP levels and LDH leakage back to control levels.ConclusionThe reactive acyl-CoA thioesters and acyl-glucuronides were not associated with liver damage, denying one of the leading hypotheses. CYP metabolism of FLP non-stereoselectively participated in Cys A-sensitive cytotoxicity, suggesting mitochondrial injury.
  • Noriaki Nagai; Fumihiko Ogata; Naohito Kawasaki; Yoshimasa Ito; Yoshinori Funakami; Norio Okamoto; Yoshikazu Shimomura
    BIOLOGICAL & PHARMACEUTICAL BULLETIN PHARMACEUTICAL SOC JAPAN 38 (7) 1063 - 1069 0918-6158 2015/07 [Refereed]
     
    Hypercalcemia is often observed in postmenopausal women as well as in patients with primary hyperparathyroidism or malignant tumors. In this study, we investigated the relationship between calcium ion (Ca2+) levels in lacrimal fluid and the rate of corneal wound healing in hypercalcemia using ovariectomized (OVX) rat debrided corneal epithelium. We also determined the effects of Ca2+ levels on cell adhesion, proliferation and viability in a human cornea epithelial cell line (HCE-T). The calcium content in bones of OVX rats decreased after ovariectomy. Moreover, the Ca2+ content in the blood of OVX rats was increased 1 month after ovariectomy, and decreased. The Ca2+ content in the lacrimal fluid of OVX rats was also increased after ovariectomy, and then decreased similarly as in blood. Corneal wound healing in OVX rats was delayed in comparison with Sham rats (control rats), and a close relationship was observed between the Ca2+ levels in lacrimal fluid and the rate of corneal wound healing in Sham and OVX rats (y=-0.7863x+8.785, R=0.78, n=25). In addition, an enhancement in Ca2+ levels caused a decrease in the viability in HCE-T cells. It is possible that enhanced Ca2+ levels in lacrimal fluid may cause a decrease in the viability of corneal epithelial cells, resulting in a delay in corneal wound healing. These findings provide significant information that can be used to design further studies aimed at reducing corneal damage of patients with hypercalcemia.
  • Masanobu Tsubaki; Tomoya Takeda; Tadahumi Tani; Hirotaka Shimaoka; Naohiro Suzuyama; Kotaro Sakamoto; Arisa Fujita; Naoki Ogawa; Tatsuki Itoh; Motohiro Imano; Yoshinori Funakami; Seiji Ichida; Takao Satou; Shozo Nishida
    INTERNATIONAL JOURNAL OF CANCER WILEY-BLACKWELL 137 (1) 243 - 250 0020-7136 2015/07 [Refereed]
     
    Oxaliplatin is a key drug commonly used in colorectal cancer treatment. Despite high clinical efficacy, its therapeutic application is limited by common, dose-limiting occurrence of neuropathy. As usual symptomatic neuropathy treatments fail to improve the patients' condition, there is an urgent need to advance our understanding of the pathogenesis of neuropathy to propose effective therapy and ensure adequate pain management. Oxaliplatin-induced neuropathy was recently reported to be associated with protein kinase C (PKC) activation. It is unclear, however, whether PKC inhibition can prevent neuropathy. In our current studies, we found that a PKC inhibitor, tamoxifen, inhibited oxaliplatin-induced neuropathy via the PKC/extracellular signal-regulated kinase (ERK)/c-Fos pathway in lumbar spinal cords (lumbar segments 4-6). Additionally, tamoxifen was shown to act in synergy with oxaliplatin to inhibit growth in tumor cells-implanted mice. Moreover, mitogen-activated protein kinase kinase (MEK) 1/2 inhibitor, PD0325901, suppressed oxaliplatin-induced neuropathy and enhanced oxaliplatin efficacy. Our results indicate that oxaliplatin-induced neuropathy is associated with PKC/ERK/c-Fos pathway in lumbar spinal cord. Additionally, we demonstrate that disruption of this pathway by PKC and MEK inhibitors suppresses oxaliplatin-induced neuropathy, thereby suggesting that PKC and MEK inhibitors may be therapeutically useful in preventing oxaliplatin-induced neuropathy and could aid in combination antitumor pharmacotherapy.
  • Corneal Wound Healing Rate Delay in Ovariectomized Rats Receiving Low-calcium Diet.
    Nagai N; Ogata F; Funakami Y; Itoh Y; Kawasaki N
    あたらしい眼科 30 (11) 1623 - 1627 2013/11 [Refereed]
  • Hajime Asano; Mizuki Watanabe; Akinori Kawaguchi; Masashi Yanae; Yoshinori Funakami; Tetsuyuki Wada; Sumio Matzno; Yuzuru Yamazoe; Shozo Nishida; Seiji Ichida
    Japanese Journal of Cancer and Chemotherapy 40 (8) 1031 - 1036 0385-0684 2013/08 [Refereed]
     
    Hiccups are often observed in patients treated with cisplatin (CDDP)-based chemotherapy. It has been reported that gender and specific dosages of CDDP and antiemetic drugs (e.g., dexamethasone and 5-HT3 receptor antagonist) using standard therapy are major risk factors in the onset of hiccups. Recently, aprepitant has been added to the antiemetic therapy in CDDP-based chemotherapy. However, it is not known how the onset of hiccups takes place in antiemetic therapy including aprepitant according to the guideline. In this study, we used cluster analysis to classify 229 patients treated with CDDP-based chemotherapy, to investigate the effect of antiemetic therapy on the onset of hiccups and chemotherapy-induced nausea and vomiting (CINV). Our analysis indicated that aprepitant was not a major risk factor for the onset of hiccups in the high CDDP dose group (≧70 mg/m2). However, an effect of antiemesis was confirmed in the standard therapy with aprepitant. In conclusion, we suggest that aprepitant is effective for CINV, without causing the onset of hiccups in patients treated with high-dose CDDP-based chemotherapy.
  • Hajime Asano; Akinori Miyamoto; Mariko Nakao; Chiyuki Wakaki; Takuma Iida; Yoshinori Funakami; Tetsuyuki Wada; Seiji Ichida
    NEUROCHEMICAL RESEARCH SPRINGER/PLENUM PUBLISHERS 37 (8) 1738 - 1746 0364-3190 2012/08 [Refereed]
     
    Previous work from this laboratory has shown that the serotonin (5-HT) induced response is significantly augmented in differentiated NG108-15 (NG) cells treated with dibutyryl cAMP (Bt(2)cAMP) due to qualitative and quantitative changes in the expression of the 5-HT3 receptor as demonstrated by specific [H-3] LY-278584 (a selective 5HT(3) receptor antagonist) binding. In this study, we investigated whether there is any change in the relative expression of the 5-HT3A and 5-HT3B subunits in NG cells differentiated following Bt(2)cAMP treatment cells. The major findings of this study were that the relative amount of 5-HT3B subunit mRNA in Bt(2)cAMP-treated NG cells 5 days following Bt(2)cAMP-treatment was greater than that in the untreated cells. In contrast, the relative expression of the 5-HT3B subunit protein in the Bt(2)cAMP-treated NG cells was much less than in the untreated cells, but the relative expression of the 5-HT3A subunit in the Bt(2)cAMP-treated NG cells was similar to the untreated cells. Therefore, no relationship between mRNA and protein expression for 5-HT3A and 5-HT3B subunits in Bt(2)cAMP treated and untreated NG cells were observed. It was also found that fluorescent intensity for the 5-HT3B subunit in the cell body of the Bt(2)cAMP treated and untreated NG cells gradually decreased from the day 1-5 after Bt(2)cAMP treatment. However, in specific areas such as the varicosity and nerve endings of the Bt(2)cAMP treated cells, staining intensity for the 5-HT3B subunits was stronger than in the untreated cells at the all time points, peaking at day 5 post-treatment. These results suggest that the augmented response induced by 5-HT acting via 5-HT3 receptors in differentiated NG cells may be due to changes in the relative amount of the 5-HT3B subunit, particularly the ratio and distribution of the 5-HT3A to (3B) subunits.
  • Yoshinori Funakami; Eiji Itoh; Taeko Hata; Tetsuyuki Wada; Seiji Ichida
    BioPsychoSocial Medicine 4 13  1751-0759 2010/11 [Refereed]
     
    Background: Specific alternation of rhythm in temperature (SART)-stressed rats, an animal model of autonomic imbalance, exhibit low blood pressure and tachycardia during consciousness and under anesthesia. In addition, these rats easily develop orthostatic hypotension (OH) as a response to postural manipulation. Hence, we studied the influence of the adrenalin α1-receptor agonist phenylephrine on stress-induced OH in SART-stressed rats and unstressed rats.Methods: Male Wistar rats weighing 250-300 g were used. Rats were fixed in the supine position under urethane anesthesia. Blood pressure was directly measured from the left common carotid artery and ECG was recorded simultaneously.Results: The maximum decrease in blood pressure and the area under the blood pressure-time curve were both large, while the %reflex was small in the SART-stressed rats compared with unstressed rats. In the SART-stressed rats, prolonged intravenous administration of phenylephrine reduced OH at a dose that barely affected unstressed rats.Conclusion: The results suggested that sympathetic dysfunction is a factor underlying SART stress-induced OH. © 2010 Funakami et al licensee BioMed Central Ltd.
  • Yoshinori Funakami; Eiji Itoh; Taeko Hata; Tetsuyuki Wada; Seiji Ichida
    BIOLOGICAL & PHARMACEUTICAL BULLETIN PHARMACEUTICAL SOC JAPAN 33 (9) 1545 - 1549 0918-6158 2010/09 [Refereed]
     
    Stress is closely associated with the manifestation and progress of irritable bowel syndrome (IBS). For the purpose of establishing experimentally the relationship between IBS and stress, the transportation capacity of the small intestine in specific alternation of rhythm in temperature (SART)-stressed animals was studied using charcoal transportation method. The charcoal suspension was administered orally into the stomach of fasting mice. Mice were sacrificed after a certain time and %charcoal transit (%CT) of the small intestine was measured. The %CTs in SART-stressed mice were greater than those in unstressed or continuously cold-stressed mice. This increase in %CT remained for I week after discontinuation of SART stress loading. Cholinergic blockers decreased %CTs in SART-stressed mice. Increases in %CT by a cholinesterase inhibitor were less in SART-stressed mice than in unstressed mice. Increases of %CT in SART-stressed mice were suppressed by Neurotropine. These results suggested that the parasympathetic hypertonicity, not just cold, played a role in the increases in the transportation capacity in SART-stressed mice and that these animals can be a useful tool for elucidation of the mechanism of IBS.
  • Kayoko Matsushima; Takashi Imanishi; Hajime Asano; Yoshinori Funakami; Tetsuyuki Wada; Seiji Ichida
    JOURNAL OF PHARMACOLOGICAL SCIENCES JAPANESE PHARMACOLOGICAL SOC 113 (3) 281 - 284 1347-8613 2010/07 [Refereed]
     
    We have reported previously that the concentration of intracellular Ca2+ evoked by serotonin (5-HT) was significantly augmented in differentiated NG108-15 (NG) cells treated with dibutyryl cAMP and the enhanced response occurred via 5-HT3 receptors. We investigated changes in the characteristics for specific binding of [H-3]LY-278584 (a specific antagonist of the 5-HT3 receptor) on membranes from differentiated NG cells. The results indicated that the K-d and B-max values for the specific binding to differentiated NG cells were significantly smaller and larger, respectively, than those for undifferentiated NG cells. The binding was significantly inhibited by 10 nM tropisetron, a specific 5-HT3 receptor antagonist, but not by any other types of 5-HT receptor antagonists. These results suggested that the enhanced response by 5-HT in differentiated NG cells was due to both qualitative and quantitative changes in the 5-HT3 receptor.
  • Takashi Imanishi; Kayoko Matsushima; Akinori Kawaguchi; Hajime Asano; Yoshinori Funakami; Tetsuyuki Wada; Takashi Masuko; Shigeru Yoshida; Seiji Ichida
    NEUROCHEMICAL RESEARCH SPRINGER/PLENUM PUBLISHERS 34 (5) 1011 - 1019 0364-3190 2009/05 [Refereed]
     
    Characteristics for the up-regulated response in the concentration of intracellular calcium ion ([Ca(2+)] (i) ) and in the sodium ion (Na(+)) current by serotonin (5-HT) were investigated in differentiated neuroblastoma x glioma hybrid NG108-15 (NG) cells. The results for the changes in [Ca(2+)] (i) by 5-HT were as follows, (1) The 5-HT-induced Ca(2+) response was inhibited by 3 x 10(-9) M tropisetron (a 5-HT(3) receptor blocker), but not by other types of 5-HT receptor blockers; (2) The 5-HT-induced Ca(2+) response was mainly inhibited by calciseptine (a L-type Ca(2+) blocker), but not by other types of Ca(2+) channel blockers or 10(-7) M TTX (a voltage-sensitive Na(+) channel blocker); (3) When the extracellular Na(+) was removed by exchange with choline chloride or N-methyl-d-glucamine, the 5-HT-induced Ca(2+) response was extremely inhibited. The results for the 5-HT-induced Na(+) current by the whole cell patch-clamp technique were as follows, (1) The 5-HT-induced Na(+) current in differentiated cells was significantly larger than that in undifferentiated cells; (2) The ED(50) value for 5-HT-induced Na(+) current in undifferentiated and differentiated cells was almost the same, about 4 x 10(-6) M each other; (3) The 5-HT-induced Na(+) current was completely blocked by 3 x 10(-9) M tropisetron, but not by other 5-HT receptor antagonists and 10(-7) M TTX. These results suggested that 5-HT-induced Ca(2+) response in differentiated NG cells was mainly due to L-type voltage-gated Ca(2+) channels allowing extracellular Na(+) to enter via 5-HT(3) receptors, but not through voltage-gated Na(+) channels.
  • Yoshinori Funakami; Taeko Hata; Eiji Itoh; Seigo Itano
    BIOLOGICAL & PHARMACEUTICAL BULLETIN PHARMACEUTICAL SOC JAPAN 30 (2) 303 - 308 0918-6158 2007/02 [Refereed]
     
    Rats stressed by specific alternation of rhythm in temperature (SART) show various symptoms of disautonomia, increased pulse rates, continuous hypotension, and severe orthostatic hypotension (OH) when they are subjected to postural change. The OH symptoms are improved by muscarinic M-2-receptor blockers. In the present study, effects of beta-adrenoceptor blocking agents on OH in SART-stressed rats were investigated. Anesthetized rats were restrained on a board in the supine position, and direct blood pressure and ECG were measured automatically using Fluclet (R) Jr.2. Postural change was performed by raising the rat's head up to a 60 degrees angle for 4 min. Unstressed rats treated with hexamethonium showed large decrease in blood pressure, small reflex from the bottom of pressure and decreased tachycardia reflex, whereas isoproterenol showed little changes. In SART-stressed rats, isoproterenol alleviated the decrease in blood pressure in postural change, brought large reflex from the bottom of pressure and increased tachycardia reflex, whereas hexamethonium had little changes. Propranolol and atenolol induced the similar changes as those seen by hexamethonium. ICI-118,551, a selective beta(2)-adrenoceptor antagonist showed large reflex from the bottom of pressure and increased tachycardia reflex in stressed rats, whereas little changes in unstressed rats. In conclusion, it was suggested that the hypotension in OH manifestation time of rats reflects the state of peripheral blood vessels, and beta(1)-adrenoceptors played a role in compensatory tachycardia reflex and beta(2)-adrenoceptors in blood pressure reflex. The circulatory regulation in SART-stressed rats seems to be poorly functioning in nervous reflex in postural changes.
  • Hata Taeko; Funakami Yoshinori; Itoh Eiji
    Japanese Journal of Psychosomatic Medicine Japanese Society of Psychosomatic Medicine 45 (9) 697 - 706 0385-0307 2005/09 
    Rats stressed by specific alternation of rhythm in temperature (SART) show various symptoms of disautonomia, continuous hypotension and tachycardia. In our study, we investigated postural change-induced orthostatic hypotension (OH) in SART-stressed rats. Each rat was restrained on a board in a supine position under anesthesia. In the SART-stressed rats during rest, both systolic and diastolic blood pressure (BP) were low and heart rate was fast, as in awake rats. Postural change was caused by tilting the rat's head up at a 60°angle for 4min. As indexes of OH, three values were used : (1) the maximum decrease in BP, (2) the reflex ratio, and (3) the area enclosed by the baseline and the time-related BP curve (AUC). In comparison to unstressed rats, SART-stressed rats showed the following changes : the maximum decrease in BP was significantly larger, the reflex-induced recovery from the maximum decrease in BP was significantly smaller, and the AUC was significantly larger. Heart rate in the stressed rats decreased soon after tilting, while it increased in unstressed rats. We conclude that postural change in SART-stressed rats can be used as an animal model of OH.
  • T Hata; Y Funakami; E Itoh
    JOURNAL OF PHARMACOLOGICAL SCIENCES JAPANESE PHARMACOLOGICAL SOC 97 (3) 386 - 392 1347-8613 2005/03 [Refereed]
     
    SART (specific alternation of rhythm in temperature)-stressed rats are an animal model of autonomic imbalance created by exposing animals to repeated cold stress. The SART-stressed rats have been shown to easily develop orthostatic hypotension (OH). In this study, effects of AF-DX116, a selective M-2 antagonist, and other muscarinic receptor antagonists on OH were investigated in SART-stressed and unstressed rats. Each anesthetized rat was canulated into the left common carotid artery, and blood pressure (BP) and heart rate were measured. Stimulation for postural change was initiated by head-up tilting. As the indices of OH, the maximum fall of BP, % reflex (recovery from maximum fall), and the area enclosed between the baseline and the recovery Curve for BP (AUC) were used. Large AUC and small % reflex in SART-stressed rats were changed, becoming similar to those of the unstressed rats by AF-DX116 and methoctoramine. Atropine and methylatropine had similar effects to AF-DX116. However, the effects of methoctoramine, atropine, and methylatropine were less than that of AF-DX116. Pirenzepine was not effective. In conclusion, it was suggested in SART-stressed rats that OH was related to hyperactivity in the parasympathetic nerve and the M2 receptor played the major role in OH.
  • H Nishikawa; T Hata; E Itoh; Y Funakami
    BIOLOGICAL & PHARMACEUTICAL BULLETIN PHARMACEUTICAL SOC JAPAN 27 (3) 352 - 356 0918-6158 2004/03 [Refereed]
     
    SART (specific alternation of rhythm in temperature) stress is known to cause anxiety-like behavior in mice/rats in several anxiety-related behavioral tests. In the present study, we investigated possible roles for corticotropin-releasing factor (CRF) and glucocorticoids in SART stress-induced anxiety-like behavior in two different anxiety-related behavioral tests. In the forced swimming test, CRF, administered intracerebroventricular (i.c.v.) at 0.5-2 pmol/mouse, dose-dependently reduced immobility time in unstressed and SART-stressed mice. alpha-Helical CRF, a specific CRIT receptor antagonist, administered i.c.v. at 0.1-1 nmol/mouse, dose-dependently increased immobility time in SART-stressed mice, but not in unstressed mice. In the elevated plus-maze test, CRF at 10-20 pmol/mouse significantly decreased the time spent in open arms in unstressed mice. CRF at a high dose tended to decrease this time in SART-stressed mice, but this decrease was not statistically significant. alpha-Helical CRIT failed to modify the time in unstressed mice. In contrast, alpha-helical CRF at 0.38 and 0.75 nmol/mouse increased the time in SART-stressed mice. Both immobility time in the forced swimming test and time spent in open arms in the elevated plus-maze test in unstressed and SART-stressed mice were unaffected by adrenalectomy. These results suggest that CRIT plays an important role in anxiety-like behavior caused by SART stress.
  • T Hata; E Itoh; Y Funakami; K Ishida; S Uchida
    JAPANESE JOURNAL OF PHARMACOLOGY JAPANESE PHARMACOLOGICAL SOC 85 (3) 313 - 321 0021-5198 2001/03 [Refereed]
     
    Rats exposed to SART (specific alternation of rhythm in temperature) stress, which are ideal animal models for vagotonia-type dysautonomia, show various changes in cardiac and circulatory systems. In this study, attention was directed to cholinergic function in the SART-stressed rat heart and the effects of AF-DX 116, a specific muscarinic M-2 antagonist, on blood pressure and heart rate. The results were compared with those obtained for atropine and pirenzepine. In SART-stressed rats, systolic and diastolic blood pressures (SBP and DBP) were lower than in unstressed rats. Oral AF-DX 116 resulted in greater elevation of DBP than SEP in unstressed rats. In stressed rats, greater and more prolonged elevation of SEP than in unstressed rats was noted, particularly at higher doses. A dose-dependent SEP change in stressed rats, caused by intravenous AF-DX 116, was shifted upward in parallel with that in unstressed groups, unlike with oral administration The positive chronotropic effect of this drug was smaller in stressed rats than in unstressed rats, in contrast to the presser effect. SART-stressed rats may thus have an enhanced sympathetic tone in the heart, as well as changes in muscarinic M-2 receptors at sympathetic nerve endings and at the heart muscle. The effects of AF-DX 116 on blood pressure and heart rate thus may arise from peripheral action and AF-DX 116 may be useful for treating hypotension related to autonomic imbalance of the vagotonia type.
  • T Hata; H Nishikawa; E Itoh; Y Funakami
    JAPANESE JOURNAL OF PHARMACOLOGY JAPANESE PHARMACOLOGICAL SOC 85 (2) 189 - 196 0021-5198 2001/02 [Refereed]
     
    To clarify the relationship between SART (specific alternation of rhythm in temperature) stress (repeated cold stress) and anxiety, the effects of various types of stress on the behavior of mice were studied in elevated plus-maze tests and then the effects of anxiolytics were evaluated. The percentage of time spent in the open arms of the plus-maze apparatus decreased in mice subjected to SART stress without change in the total number of arm entries. No change was noted in mice subjected to other stresses, such as l-h, 2-day and 5-day cold stress and l-h, 15-h and 5 x 15-h restraint stress. The reduction in the percentage of time spent in the open arms caused by SART stress was inhibited by single and repeated administrations of diazepam and alprazolam and by a single administration of buspirone, which have no influence on the percentage of time spent in the open arms in nonstressed mice, but not by flumazenil, WAY-100635 and chronic treatment with buspirone. The effects of diazepam and buspirone were antagonized by flumazenil and WAY-100635, respectively. The behavior of SART-stressed mice in the plus-maze would thus appear to arise from anxiety, to which benzodiazepine and serotonin receptors are related, but the diazepam binding inhibitor, an endogenous anxiogenic protein, is not. Thus SART-stressed animals may be useful for investigating the psychopharmacological and neuropharmacological basis of anxiety.

MISC

Research Grants & Projects

  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2023/04 -2026/03 
    Author : 船上 仁範
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2019/04 -2022/03 
    Author : FUNAKAMI Yoshinori
     
    We investigated how chronic stress affects hippocampal neurogenesis to cause depression. The following findings were obtained: (1) Chronic stress decreases hippocampal neurogenesis involved in emotional experience and memory.(2) Neuron-specific RNA-binding protein Hu is involved in hippocampal neurogenesis.(3) Chronic stress reduces the expression of RNA-binding protein Hu, which plays an important role in neuronal differentiation. These results suggest that chronic stress reduces hippocampal neurogenesis via decreased expression of Hu protein.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2016/10 -2019/03 
    Author : FUNAKAMI Yoshinori
     
    We investigated the effect that chronic stress condition gave for natural immunity. As a result, we obtained the following findings. (1) The chronic stress reduces a phagocytic activity of the alveolar macrophage and a production of inflammatory cytokine. (2) Sympathetic hypotonia is involved in a decrease of the phagocytic activity in the alveolar macrophage. (3) The phagocytic activity decrease of the chronic stress-induced alveolar macrophage is improved by a beta 2 receptor stimulant drug.These results suggest that the chronic stress reduces natural immunity through a beta 2 receptor.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2013/04 -2016/03 
    Author : ICHIDA Seiji; NISHIDA Shozo; FUNAKAMI Yoshinori
     
    We investigated whether chronic stress influences on cancer metastatic ability using a lung cancer metastasis model B16BL6 cell. As a result, we obtained the following findings. 1) The cancer metastasis and the tumor growth in B16BL6 cell were promoted in chronically stressed mice. 2) The number of NK cell and alveolar macrophage and the phagocytic activity of the macrophage in the chronically stressed mice were decreased. It is suggested from these results suggest that the cancer metastatic ability of B16BL6 cell in chronically stressed mice is prompted so that the immunocompetence of the alveolar macrophage is decreased in the chronically stressed mice.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)
    Date (from‐to) : 2011 -2012 
    Author : FUNAKAMI Yoshinori
     
    I examined functional changes of the central nervous system (CNS) using SART-stressed mice in the formation process of chronic stress related to the onset of illness. Chronic stress reduced the neural activity of the hypothalamic paraventricular nucleus (PVN), the dorsomedial hypothalamic nucleus (DMH) and the Pallidal raphe nucleus (RPa) gradually. It was observed that chronic stress decreased the neural activity of the CRF neuron in PVN. These abnormalities were improved by the anti-anxiety drug diazepam. In SART-stressed mice, it was suggested that the chronic stress-induced abnormality of the neural activity of PVN, DMH and RPa, which is involved in the autonomic nervous system and endocrine system, is broken homeostasis. It was thought that the SART stress-induced decrease of neural activity in DMH is related to blood pressure regulation and could be one factor in hypotension onset.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)
    Date (from‐to) : 2008 -2009 
    Author : FUNAKAMI Yoshinori
     
    The SART (specific alternation of rhythm in temperature)-stressed rat, which is a model animal of autonomic imbalance, is associated with low blood pressure and tachycardia under both consciousness and anesthesia. Additionally, orthostatic hypotension (OH) is developed easily by postural manipulation of SART-stressed rats. Accordingly, we studied the influence of the adrenalin α1 receptor agonist phenylephrine on stress-induced OH. In SART-stressed rats, prolonged intravenous administration of phenylephrine reduced OH. Sympathetic dysfunction is suggested to be a factor underlying SART stress-induced OH.

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