| Project/Area Number |
09470018
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Environmental physiology (including Physical medicine and Nutritional physiology)
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| Research Institution | Waseda University |
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Principal Investigator |
SHIBATA Shigenobu Waseda University School of Human Sciences, Pharmacology, Professor, 人間科学部, 教授 (10162629)
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| Co-Investigator(Kenkyū-buntansha) |
池田 真之 早稲田大学, 人間総合研究センター, 助手 (10288053)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1998: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | Circadian / biological rhythm / suprachiasmatic nucleus / glia / GFAP / clock / serotonin / mutant animals / 体内時計 / グリア / ノックアウト / 不眠症 / ノックアウトマウス / 同調 |
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| Research Abstract |
In order to clarify the role of GFAP-expressing astrocytes in the circadian clock, we compared the activity rhythms of GFAP mutant mice to those of wild-type mice in various lighting conditions. GFAP mutant mice exhibited stable circadian rhythms both in light-dark cycles and constant darkness and showed normal entrainment to environmental light stimuli. However, under constant lighting conditions, the period of the activity rhythm in GFAP mutant mice was longer and more disrupted than in wild-type mice. HPLC analysis revealed that serotonergic activity in the suprachiasmatic nucleus, which is the center of the circadian clock, and the raphe nuclei was reduced m GFAP mutant mice. Furthermore, housing for 80 days under constant light decreased GFAP expression in the suprachiasmatic nucleus of C57BL/6J mice while increasing GFAP expression in the intergeniculate leaflet. These results demonstrate that the activities of GFAP expressed in astrocytes were changed in the suprachiasmatic nucleus and the intergeniculate nucleus under constant lighting conditions. Astrocytes in the suprachiasmatic nucleus may play important roles in the maintenance of circadian rhythms under constant lighting conditions via regulation of serotonergic activity.
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