【摘要】 目的 :研究不同浓度特别是高浓度肌酸在离体条件下对骨骼肌收缩能力以及对葡萄糖跨膜转运进入骨骼肌细胞速率的影响。方法 :对在不同肌酸浓度孵育液中的大鼠比目鱼肌进行最大强直等长收缩刺激 ,分析收缩力输出量时间变化曲线和收缩力总量 ,并用同位素双标法测定肌肉收缩后葡萄糖跨膜转运速率。结果 :大剂量肌酸浓度条件下骨骼肌收缩力明显下降 (P <0 0 5 ) ,并存在剂量———反应的负相关关系 (P <0 0 5 )。当肌酸浓度在正常范围内时 ,骨骼肌收缩力保持在较高水平。在各种肌酸浓度下葡萄糖转运速率改变不明显 (P >0 0 5 )。结论 :离体条件下高浓度肌酸对骨骼肌收缩能力造成不利影响 ,提示运动员应适量补充肌酸 ,不可大量或超量使用 ,以免对运动能力造成负面影响。骨骼肌收缩后葡萄糖跨膜转运的速率不受肌酸的影响更多还原

【Abstract】 Objective To investigate the effects of creatine at different concentrations, especially at high contents, on muscle contraction capacity and glucose transport rate in vitro. Methods The rat soleus muscles incubated in the media with different creatine contents were stimulated electrically to yield maximal tetanic isometric contraction. The force output was measured and the time course of dose-response curve between the creatine concentration and force output was analyzed. The glucose transport rate after muscle contraction was determined by a double isotopes label method. Results The muscle contraction force outputs at high creatine concentrations were decreased significantly ( P <0 05) and there were negative dose-response correlations between high creatine concentration and contraction force output ( P <0 05). However, the force outputs were kept at relatively higher level when the creatine content was in the normal extent. The glucose transport rates after contraction were unchanged among the muscle groups in the different creatine content media ( P >0 05). Conclusion The result that high content of creatine has negative effect on muscle contraction capacity in vitro suggests that athletes should not have high or ultra dose of creatine supplementation, but instead of suitable dose in order to avoid possible adverse influence on exercise performance. Creatine has no effect on glucose transport rate in muscle after contraction.更多还原