Lees S J, Franks P D, Spangenburg E E, Williams J H
Muscular Function Laboratory, Department of Human Nutrition, Foods, and Exercise, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
J Appl Physiol (1985). 2001 Oct;91(4):1638-44. doi: 10.1152/jappl.2001.91.4.1638.
The purpose of the present study was to investigate the effects of fatiguing muscular activity on glycogen, glycogen phosphorylase (GP), and Ca(2+) uptake associated with the sarcoplasmic reticulum (SR). Tetanic contractions (100 ms, 75 Hz) of the gastrocnemius and plantaris muscles, elicited once per second for 15 min, significantly reduced force to 26.5 +/- 4.0% and whole muscle glycogen to 23% of rested levels. SR glycogen levels were 415.4 +/- 76.6 and 20.4 +/- 2.1 microg/mg SR protein in rested and fatigued samples, respectively. The optical density of GP from SDS-PAGE was reduced to 21% of control, whereas pyridoxal 5'-phosphate concentration, a quantitative indicator of GP content, was significantly reduced to 3% of control. GP activity after exercise, in the direction of glycogen breakdown, was reduced to 4% of control. Maximum SR Ca(2+) uptake rate was also significantly reduced to 81% of control. These data demonstrate that glycogen and GP associated with skeletal muscle SR are reduced after fatiguing activity.
本研究的目的是调查疲劳性肌肉活动对糖原、糖原磷酸化酶（GP）以及与肌浆网（SR）相关的钙离子摄取的影响。对腓肠肌和比目鱼肌进行强直收缩（100毫秒，75赫兹），每秒引发一次，持续15分钟，会使力量显著降低至静息水平的26.5±4.0%，全肌肉糖原降低至静息水平的23%。在静息和疲劳样本中，SR糖原水平分别为415.4±76.6和20.4±2.1微克/毫克SR蛋白。SDS-PAGE中GP的光密度降低至对照的21%，而作为GP含量定量指标的磷酸吡哆醛5'-磷酸浓度显著降低至对照的3%。运动后朝着糖原分解方向的GP活性降低至对照的4%。最大SR钙离子摄取率也显著降低至对照的81%。这些数据表明，疲劳性活动后，与骨骼肌SR相关的糖原和GP会减少。
