Gonzalez-Serratos H, Somlyo A V, McClellan G, Shuman H, Borrero L M, Somlyo A P
Proc Natl Acad Sci U S A. 1978 Mar;75(3):1329-33. doi: 10.1073/pnas.75.3.1329.
Electron probe analysis, cryo-ultramicrotomy, and freeze-substitution were used to determine the nature of vacuolation and the subcellular composition in fatigued frog skeletal muscle fibers. The vacuoles caused by fatigue were part of the T-tubule system and contained high concentrations of NaCl. The calcium concentration in the terminal cisternae was higher than previously measured normal resting values. Mitochondrial calcium content was relatively low (mean +/- SEM, 2 +/- 2 mmol/kg dry weight). Fiber NaCl was increased. It is concluded that fatigue is not due to the depletion of calcium stores from the terminal cisternae or to uncoupling of mitochondria due to calcium loading but may be caused by multiple mechanisms including failure of the T-tubule action potential.
采用电子探针分析、冷冻超薄切片术和冷冻置换法来确定疲劳青蛙骨骼肌纤维中空泡化的性质和亚细胞组成。疲劳引起的空泡是横管系统的一部分，含有高浓度的氯化钠。终池中的钙浓度高于先前测量的正常静息值。线粒体钙含量相对较低（平均值±标准误，2±2 mmol/kg干重）。纤维中的氯化钠增加。得出的结论是，疲劳并非由于终池中钙储备的耗尽或钙负荷导致线粒体解偶联，而是可能由多种机制引起，包括横管动作电位的衰竭。
