McComas A J, Galea V, Einhorn R W
Department of Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada.
Muscle Nerve. 1994 Jun;17(6):599-607. doi: 10.1002/mus.880170606.
The possible causes of the transient enlargement of muscle compound action potentials during repetitive stimulation ("pseudofacilitation") are considered. The phenomenon cannot be due to mechanical artefact, while hypersynchronization of the muscle fiber action potentials, the usual explanation, can only make a minor contribution. A more convincing explanation, for which there is now experimental evidence, is that the muscle fibers undergo hyperpolarization, due to the intramuscular release of norepinephrine and consequent stimulation of the electrogenic Na+,K(+)-pump. Defective phosphorylation of the Na+,K(+)-pump is a possible cause of the transient weakness and myotonia in myotonic dystrophy.
本文探讨了重复刺激期间肌肉复合动作电位短暂增大（“假易化”）的可能原因。该现象并非由机械伪迹引起，而通常认为的肌纤维动作电位超同步化仅起较小作用。现在有实验证据支持的一个更有说服力的解释是，由于去甲肾上腺素在肌肉内释放并随后刺激生电钠钾泵，肌纤维发生了超极化。钠钾泵磷酸化缺陷可能是强直性肌营养不良中短暂性肌无力和肌强直的一个原因。
