骨骼肌兴奋收缩偶联时肌浆网内Ca^(2+)释放的形态-功能变化研究

Research on Ca^(2+) concentration change during SR Ca^(2+) release at skeletal muscular excitation -contraction coupling

采用双向红外线探测器 计算机控制的电刺激 超低温快速冷冻固定同步技术、透射电子显微镜、X 射线能量色散谱及Ca2 +细胞化学技术 ,从超微结构形态学角度 ,实时研究并获取骨骼肌兴奋 收缩偶联时 ,肌浆网内Ca2 +释放及肌浆网的形态改变。研究表明 :1 骨骼肌组织在收缩潜伏期内 ,肌浆网膜与T 管膜接触。 2 在潜伏期 ( <10ms)内 ,肌浆网内的钙离子浓度随时间经历的延长而减少。 3 骨骼肌组织在收缩潜伏期开始 0 8ms时 ,在T 管外周围 (纳米处 ) ,有Ca2 +分布 ,可以认为骨骼肌兴奋收缩偶联时 ,T 管外存在Ca2

The ultrastructural change of sarcoplasmic reticulum and Ca 2+ distribution during excitation contraction coupling were studied by electron microscopy and real synchronism processing technique. The skeletal muscle stimulated were processed by cryofixation and cryosubstitution with the system of real synchronism processing and ultra rapid freezing. The skeletal muscular ultrastructure, concentration and situs of Ca 2+ were analyzed by the analytic TEM and X ray energy dispersive system. The results showed that the sarcoplasmic reticulum membrane contacted to the membrane of T tube during latency and the concentration of Ca 2+ was depressed along with the time extend. It is demonstrated that the genesis mechanism of excitation contraction coupling is same with the direct contact signal transduction (DCT) hypothesis for skeletal muscle.