| Project/Area Number |
14380007
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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 |
体育学
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| Research Institution | University of Tsukuba |
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Principal Investigator |
SOYA Hideki University of Tsukuba, Institute of health and Sports Science, Assistant professor, 体育科学系, 助教授 (50221346)
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| Co-Investigator(Kenkyū-buntansha) |
KIZUKA Tomohiro University of Tsukuba, Institute of Basic Medical Science, Instructor, 体育科学系, 講師 (30323281)
SAKURAI Takeshi University of Tsukuba, Institute of Basic Medical Science, Assistant professor, 基礎医学系, 助教授 (60251055)
HONDA Kazuki Tokyo Medical and Dental University, Assistant professor, 生体材料工学研究所, 助教授 (70173656)
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| Project Period (FY) |
2002 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥15,100,000 (Direct Cost: ¥15,100,000)
Fiscal Year 2003: ¥5,000,000 (Direct Cost: ¥5,000,000)
Fiscal Year 2002: ¥10,100,000 (Direct Cost: ¥10,100,000)
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| Keywords | orexin / Narucolepsy / Cataplexy / prepro-orexin Knoch-out mice / ataxin-3 Trans genic mice / antigravity muscle / muscle tone / Soleus muscle / 筋トヌス,筋形質 / 筋トヌス / 運動ストレス / 脳の覚醒 / ストレス反応抗 / 抗重筋 / 筋緊張 |
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| Research Abstract |
Orexins are recently isolated neuropeptides by Sakurai et al. in 2448, and found to be produced in the lateral hypothalamus area. Orexinergic dysfunction causes to narcolepsy, which is featured by cataplexy, a sudden loss of skeletal muscles tone maintaining posture. It was certified that firing of noradrenalinergic neurons in the locus ceruleus (LC) in the brain stem, the control center of skeletal muscles tone maintaining posture, ceased during cataplexy, and that extrinsic orexins microinjection into LC produced muscle tone facilitation
In this study, we investigated whether orexins take part in keeping muscle tone and phenotypic profiles, through LG neurons, which control the firing of a motor neurons, managing antigravity muscles maintaining posture. We examined the morphology of hindlimb muscles of prepro-orexin knock-oat (KO) mice whose orexins precursor gene deficit, and orexin/ataxin-3 transgenic mice whose orexinergic neurons are removed in the growth process
Hindlimb muscles weight pre body weight (the relative weight) KO mice in were lower than that of wild-type mice. Particularly the relative weight of soleus muscle, antigravity muscle, was 30% lower than that of wild type mice. Fiber type and myosin heavy chain (MHC) composition of soleus muscle in KO mice had slightly richer slow type than that of wild type mice. This phenomenon only found in soleus muscle. In other hand, the relative weight of soleus muscle in Tg mice lower than that in wild type mice from 12-15 week, at the time that orexinergic neurons had been completely abolished. However there were no differences in fiber type and MHC composition of soleus muscle between genotype. The present study suggests that endogenous orexin is one of the central factors which play a role. in maintenance of skeletal muscles phenotypic features
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