Alterations in function of sarcoplasmic reticulum after acute high-intensity exercise.
- VernacularTitle:一過性の高強度運動による筋小胞体機能の変化
- Author:
SATOSHI MATSUNAGA
;
HIROTSUGU TUCHIMOCHI
;
SHUICHIRO INASHIMA
;
TOSHIO HAZAMA
;
SHIGEMITSU NIIHATA
;
MASANOBU WADA
- Publication Type:Journal Article
- Keywords:
sarcoplasmic reticulum;
Ca2+ uptake;
muscle fatigue;
Ca2+-ATPase activity;
creatine kinase
- From:Japanese Journal of Physical Fitness and Sports Medicine
2000;49(1):139-147
- CountryJapan
- Language:Japanese
-
Abstract:
This study examined the impact of acute high-intensity exercise on the rate of Ca2+uptake and release and Ca2+-stimulated adenosine triphosphatase (ATPase) activity of the sarcoplasmic reticulum (SR) in the soleus muscle (SOL) and the superficial region of the vastus lateralis muscle (VS) of rats. The animals were run on a 10% grade at 50 m/min of a motorized treadmill until fatigued (The average time to exhaustion was 306 sec.) . At exhaustion, glycogen concentrations were 65% and 85% less in the SOL and VS, respectively. The rate of Ca2+release induced by 4-chloro-m-cresol was un-changed in fatigued SOL and VS. The rate of Ca2+uptake stimulated by adenosine triphosphate (ATP) was significantly lower following exercise in VS but not in SOL. This lower rate observed in VS was paralleled by decreased catalytic activity of SR Ca2+-ATPase. The rate of Ca2+ uptake measured using adenosine diphosphate and phosphocreatine, as substrate was lower than that of ATP in fatigued VS. These findings suggest that, in fast-twitch muscles, high-intensity exercise not only reduces SR Ca2+-ATPase activity but also elicits a decrease in creatine kinase activity, probably resulting from nitric oxide that is produced during exercise.
