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Effects of endurance training and acute exercise on sarcoplasmic reticulum function

耐力训练和急性运动对肌浆网功能的影响

基本信息

批准号：
11680032
负责人：
WADA Masanobu
金额：
$ 2.05万
依托单位：
Hiroshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11680032/
关键词：
sarcoplasmic reticulum endurance training muscular fatigue Ca^<2+>-ATPase Ca^<2+> release rate Ca^<2+> uptake rate SR Ca^<2+>-ATPase

项目摘要

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.

本研究旨在观察耐力训练和/或急性运动对骨骼肌纤维肌浆网（SR）钙摄取和释放速率及钙激活的三磷酸腺苷酶（ATP酶）活性的影响。经过10周的训练后，一半的训练和未训练的大鼠进行中等强度的跑步，直到精疲力竭。跑台训练可使大鼠足底肌SR Ca^2+摄取率和Ca^2+-ATP酶活性降低，但对比目鱼肌SR Ca^2+摄取率和Ca^2+-ATP酶活性无明显影响。力竭运动后即刻，两块肌肉的SR均出现功能障碍，SOL的变化更为明显，PL的Ca^<2+>摄取率和Ca^<2+>-ATP酶活性仅在未经训练的肌肉中出现下降。在SOL的情况下，在未训练和训练的肌肉中，Ca^2+释放速率以及Ca ^2+摄取速率和Ca^2+-ATP酶活性都受到不利影响。在这些变化的程度方面，经过培训和未经培训的SOL之间不存在差异。然而，未训练的SOL中Ca^2+摄取和释放速率的平均下降速率（以单位时间至耗尽的Δ摄取或释放速率表示）比训练的SOL高约2倍。未能恢复在运动SOL和PL中观察到的降低的催化活性。这些发现表明，运动诱导的SR Ca^<2+>-ATP酶可能不是由SR Ca^<2+>-ATP酶蛋白上的巯基氧化引起的，耐力训练可能能够延缓运动期间SR功能的抑制率。