| Project/Area Number |
09670077
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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 | The Jikei University School of Medicine, Tokyo |
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Principal Investigator |
UMAZUME Yoshiki The Jikei University, Department of Physiology, Professor, 医学部, 教授 (40056990)
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| Co-Investigator(Kenkyū-buntansha) |
ONO Tetsuo The Jikei University, Department of Physiology, Assistant, 医学部, 助手 (30233224)
TAKEMORI Shigeru The Jikei University, Department of Physiology, Lecturer, 医学部, 講師 (20179675)
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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 |
¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1998: ¥700,000 (Direct Cost: ¥700,000)
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| Keywords | Skeletal Muscle / BDM / Fatigue / X-ray diffraction / 筋原線維 |
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| Research Abstract |
We investigated the molecular mechanisms of the inhibiting effects of BDM (2, 3-butanedione monoxime) on the actomyosin interaction and compared them with the properties of actomyosin during the skeletal muscle fatigue. Using a strong synchrotron radiation source, the effects of BDM on the molecular structure of myosin and actin in the living and skinned skeletal muscle fibres. In the resting states, BDM significantly increased the resting equatorial intensity ratio. Also BDM suppressed the Ca ion activated contraction, whereas the equatorial intensity ratio was close to the value in normal contraction. BDM also reduced the intensity increase of the meridional actin layer lines and intensity decrease of the second myosin meridional during activation indicating that BDM suppresses the skeletal muscle contraction by mainly inhibiting actomyosin interaction. It has a smaller effect on the equatorial reflections and myosin layer-lines than on the actin layer lines, suggesting that BDM-influenced myosin heads may bind to actin without following the symmetry of the actin helix. We also studied the effects of BDM on the skeletal myofibrils shortening. BDM has little effects on the unloaded shortening, but clearly slowed the loaded shortening. These effects of BDM seems similar to the properties of fatigue skeletal muscles, and indicates BDM treated muscles to be a good experimental model of skeletal muscle fatigue.
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