| Project/Area Number |
11680032
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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 |
体育学
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| Research Institution | Hiroshima University |
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Principal Investigator |
WADA Masanobu Hiroshima Univ., Faculty of Integrated Arts & Sciences, Associate Professor, 総合科学部, 助教授 (80220961)
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| Co-Investigator(Kenkyū-buntansha) |
HASEGAWA Hiroshi Hiroshima Univ., Faculty of Integrated Arts & Sciences, Research Associate, 総合科学部, 助手 (70314713)
新畑 茂充 広島大学, 総合科学部, 教授 (60117843)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2000: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1999: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | sarcoplasmic reticulum / endurance training / muscular fatigue / Ca^<2+>-ATPase / Ca^<2+> release rate / Ca^<2+> uptake rate / SR Ca^<2+>-ATPase |
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| Research Abstract |
The purpose of this study was to examine the effect of endurance training and/or an acute bout of exercise on Ca^<2+> uptake and release rate and Ca^<2+>-stimulatated adenosine triphosphatase (ATPase) activity of sarcoplasmic reticulum (SR) in skeletal muscle fibers. Following 10 weeks of training, one-half of trained and untrained rats were subjected to moderate-intensity runs to exhaustion. A training program of treadmill running elicited depressions in SR Ca^<2+> uptake rate and Ca^<2+>-ATPase activity in the plantaris muscle (PL), but not in the soleus muscle (SOL). Immediately after exhaustive running, the dysfunction of SR occurred in both muscles, with more pronounced alterations being observed in SOL.In PL, acute exercise brought about reductions in Ca^<2+> uptake rate and Ca^<2+>-ATPase activity in only untrained muscles. In the case of SOL, Ca^<2+> release rate as well as Ca^<2+> uptake rate and Ca^<2+>-ATPase activity were adversely affected in both untrained and trained muscles. No differences existed between trained and untrained SOL with regard to the extent of these changes. However, the mean rates of the decline of Ca^<2+> uptake and release rates, expressed as Δ uptake or release rates per time to exhaustion, were approximately 2-fold higher in untrained SOL than in trained SOL.Incubation of dithiothreitol, a disulfide reducing agent, failed to restore the decreased catalytic activity observed in exercised SOL and PL.These findings suggest that exercise-induced decline in SR Ca^<2+>-ATPase may not be caused by an oxidation of sulfhydryl groups on SR Ca^<2+>-ATPase protein and that endurance training may be capable of delaying th depression rate of SR function that occurred during exercise.
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