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FacultyDepartment of Life Science
PositionAssistant Professor
DegreePh.D. in Medicine
Commentator Guide
Last Updated :2020/09/01

Education and Career


  •   2009 04  - 2013 03 , The University of Tokushima, Faculty of Medicine
  •   2013 04  - 2015 03 , The University of Tokushima, Graduate School of Nutrition and Bioscience
  •   2015 04  - 2019 03 , The University of Tokushima, Graduate School of Medical Sciences

Academic & Professional Experience

  •   2019 04 ,  - 現在, Faculty of Science and Engineering, Department of Life Science, Kindai University

Research Activities

Research Areas

  • Life sciences, Nutrition and health science

Published Papers

  • Role of orexin in exercise-induced leptin sensitivity in the mediobasal hypothalamus of mice., 514, 166 - 172, Jun. 2019 , Refereed
  • Sufficient intake of high-fat food attenuates stress-induced social avoidance behavior, Life Sciences, Life Sciences, 219, 219 - 230, Feb. 2019 , Refereed
  • Enhancement of fear learning in PPARα knockout mice, Chikahisa S, Chida D, Shiuchi T, Harada S, Shimizu N, Otsuka A, Tanioka D, Séi H, Behavioural Brain Research, Behavioural Brain Research, 359, 664 - 670, Feb. 2019 , Refereed
  • Modification of Energy Metabolism and Higher Brain Function by Feeding Rhythm, Otsuka Airi, Shiuchi Tetsuya, YAKUGAKU ZASSHI, YAKUGAKU ZASSHI, 138(10), 1297 - 1304, 2018 , Refereed
  • Physiological changes in response to social isolation in male medaka fish, Airi Otsuka, Moeko Inahata, Yuki Shimomura, Nao Kagawa, Fisheries Science, Fisheries Science, Jul. 17 2020 , Refereed
  • The presence of a conspecific induces risk-taking behaviour and enlargement of somata size of dopaminergic neurons in the brain of male medaka fish., Airi Otsuka, Kenta Shimomura, Haruka Niwa, Nao Kagawa, Journal of fish biology, Journal of fish biology, 96(4), 1014 - 1023, Apr. 2020 , Refereed
    Summary:Boldness and risk-taking behaviours in animals are important traits to obtain advantages such as habitation, food resources, reproductive success and social dominance. Risk-taking behaviour is influenced by physiological and environmental conditions; however, whether individual fish become bolder by the presence of conspecifics remains unknown. In this study, a light-dark preference test was conducted using medaka fish (Oryzias latipes) with or without a neighbouring conspecific. It was found that individual medaka male fish preferred a light environment and avoided a dark environment, whereas the display of a neighbouring conspecific enhanced the time the male spent in the dark environment (i.e., this condition encouraged risk-taking). The blood glucose level increased in fish confined to the dark condition but did not increase in light-preferring fish and risk-taking fish. Large somata expressing tyrosine hydroxylase, which is the rate-limiting enzyme in dopamine synthesis, were detected in the telencephalic and diencephalic brain regions in risk-taking medaka, whereas large somata were detected in the diencephalic region in medaka confined to the dark condition. These findings indicated that medaka is a good fish model to explore the central roles of dopaminergic neurons in the telencephalon and the diencephalon, which regulate risk-taking behaviour.
  • Mast cell involvement in glucose tolerance impairment caused by chronic mild stress with sleep disturbance, Sachiko Chikahisa, Saki Harada, Noriyuki Shimizu, Tetsuya Shiuchi, Airi Otsuka, Seiji Nishino, Hiroyoshi Sei, SCIENTIFIC REPORTS, SCIENTIFIC REPORTS, 7(1), Oct. 2017 , Refereed
    Summary:We have developed a chronic mild stress (MS) mouse model by simply rearing mice on a wire net for 3 weeks and investigated the effects of MS on glucose homeostasis and sleep. MS mice showed impaired glucose tolerance and disturbed sleep. One-week treatment with a histamine H1 receptor antagonist (H1RA) ameliorated the glucose intolerance and improved sleep quality in MS mice. MS mice showed an increased number of mast cells in both adipose tissue and the brain. Inhibition of mast cell function ameliorated the impairment in both glucose tolerance and sleep. Together, these findings indicate that mast cells may represent an important pathophysiological mediator in sleep and energy homeostasis.
  • Late feeding in the active period decreases slow-wave activity, Kanna Oura, Airi Otsuka, Tetsuya Shiuchi, Sachiko Chikahisa, Noriyuki Shimizu, Hiroyoshi Sei, LIFE SCIENCES, LIFE SCIENCES, 160, 18 - 26, Sep. 2016 , Refereed
    Summary:Aims: Sleep and feeding behaviors closely interact to maintain energy homeostasis. While it is known that sleep disorders can lead to various metabolic issues such as insulin resistance, the mechanism for this effect is poorly understood. We thus investigated whether different feeding rhythms during the active period affect sleep-wake regulation. Main methods: For 2 weeks, mice were randomly assigned to 1 of 3 feeding schedules as follows: free access to lab chow during the active period (ZT12-24, Ad-lib group), free access to lab chow during the first half of the active period (ZT12-18; Morning group), or free access to lab chow during the second half of the active period (ZT18-24, Evening group). Food intake, body weight, body temperature, locomotor activity, and sleep were evaluated. The hypothalamus and cerebral cortex were examined post-mortem. Key findings: No alterations in food intake or body weight were observed among the 3 groups. The Evening group showed lower slow-wave activity (SWA) than the other 2 groups, in addition to higher expression of orexin mRNA in the hypothalamus and higher concentrations of dopamine and its metabolites in the cerebral cortex. AMPK phosphorylation was increased in the hypothalamus of mice in the Evening group; however, AMPK inhibition had no effect on SWA. Significance: We concluded that late feeding reduces SWA in NREM sleep via a mechanism that involves orexin-mediated arousal in the hypothalamus and elevated monoamines in the cerebral cortex. These data have important implications for the relationship between sleep-wake disturbances and metabolic disorders. (C) 2016 Elsevier Inc. All rights reserved.
  • Voluntary exercise and increased food intake after mild chronic stress improve social avoidance behavior in mice, Airi Otsuka, Tetsuya Shiuchi, Sachiko Chikahisa, Noriyuki Shimizu, Hiroyoshi Sei, PHYSIOLOGY & BEHAVIOR, PHYSIOLOGY & BEHAVIOR, 151, 264 - 271, Nov. 2015 , Refereed
    Summary:It is well-established that exercise can influence psychological conditions, cognitive function, and energy metabolism in peripheral tissues including the skeletal muscle. However, it is not clear whether exercise can influence social interaction with others and alleviate defeat stress. This study investigated the effect of voluntary wheel running on impaired social interaction induced by chronic social defeat stress (SDS) using the resident intruder social defeat model. Mice were divided into three groups: control, stress alone, and stress + exercise. SOS was performed by exposing C57BL/6 mice to retired ICR mice for 2.5 min. The C57BL/6 mice were continuously defeated by these resident (aggressor) mice and, following 5 days of SDS, experienced 2 days of rest with no SOS. Mice in the stress + exercise group were allowed to voluntarily run on a wheel for 2 h after every SDS exposure. Two weeks later, compared to the control group, the stress group showed a higher ratio of time spent in the corner zone of a social interaction paradigm even though SDS did not elicit depressive- and anxiety-like behaviors. We also observed that voluntary exercise, which did not affect muscle weight and gene expression, decreased social avoidance behavior of stressed mice without clear changes in brain monoamine levels. Interestingly, food intake in the stress + exercise group was the greatest among the three groups. To test the effect of the exercise-induced increase in food intake on social behavior, we set up a pair-fed group where food intake was restricted. We then compared these mice to mice in the stress alone group. We found that the ratio of time spent in the corner zone of the social interaction test was not different between ad libitum- and pair-fed groups, although pair-fed mice spent more time in the corner zone when an aggressor mouse was present than when it was absent. In addition, pair-feeding did not show exercise-induced reductions of adrenal gland weight and enhanced the loss of body fat. Our findings indicate that voluntary exercise reduces social avoidance behavior induced by SDS. Further, we determined that SOS and exercise-induced increases in food intake partially influence energy metabolism and social avoidance behavior. (C) 2015 Elsevier Inc All rights reserved.


  • Physical exercise improve social interaction induced by social-defeated stress, Airi Otsuka, Tetsuya Shiuchi, Sachiko Chikahisa, Junji Terao, Hiroyoshi Sei, FASEB JOURNAL, 29,   2015 04
  • Hypothalamic AgRP-mediated energy metabolism in skeletal muscle is a critical regulatory system in feeding rhythm-induced insulin resistance, Tetsuya Shiuchi, Airi Otsuka, Sachiko Chikahisa, Noriyuki Shimizu, Hiroyoshi Sei, FASEB JOURNAL, 29,   2015 04