Saito K, Ozawa E
J Cell Physiol. 1986 Dec;129(3):289-94. doi: 10.1002/jcp.1041290304.
A possible function of Ca store site in cultured chick myotubes was examined by recording contraction of the myotube with special reference to the effect of caffeine. Caffeine at low concentrations (below 1 mM), applied focally on the myotube through a micropipette with a pressure pulse, elicited focal contraction without membrane potential changes. Procaine inhibited the caffeine contracture. Deuterium oxide also inhibited the caffeine contracture at low concentrations, but enhanced the maximal contracture. These observations are similar to those in the mature frog muscle fiber in which the sarcoplasmic reticulum (SR) is a main site of caffeine action. On the basis of these similarities, it was considered that caffeine acts on SR to elicit contracture in the myotube. The ability of SR to accumulate and release Ca ion seemed to be low, because caffeine contracture decreased or disappeared in a Ca-free solution in many myotubes.
通过记录肌管收缩，并特别参考咖啡因的作用，研究了培养的鸡肌管中钙储存位点的可能功能。低浓度（低于1 mM）的咖啡因通过带有压力脉冲的微量移液器局部施加到肌管上，引发局部收缩且无膜电位变化。普鲁卡因抑制咖啡因挛缩。氧化氘在低浓度时也抑制咖啡因挛缩，但增强了最大挛缩。这些观察结果与成熟青蛙肌纤维中的相似，在青蛙肌纤维中，肌浆网（SR）是咖啡因作用的主要位点。基于这些相似性，认为咖啡因作用于肌浆网以引发肌管挛缩。肌浆网积累和释放钙离子的能力似乎较低，因为在许多肌管中，咖啡因挛缩在无钙溶液中减少或消失。
