IS POTASSIUM CONDUCTANCE OF CARDIAC PURKINJE-FIBERS CONTROLLED BY [CA2+1I]
IS POTASSIUM CONDUCTANCE OF CARDIAC PURKINJE-FIBERS CONTROLLED BY [CA2+1I]
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DOI：
10.1038/253273a0
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发表时间：
1975-01-01
期刊：
影响因子：
64.8
通讯作者：
ISENBERG, G
中科院分区：
文献类型：
--
作者：
ISENBERG, G
细胞外Ca 2+浓度升高1、长时间高剂量心脏糖苷类药物治疗2和代谢抑制3缩短心肌动作电位。在这些条件下，细胞内游离Ca 2+可能会增加，细胞内Ca 2+的增加可能会通过影响Ca 2+内向电流或通过增加钾渗透性来缩短动作电位4。后一种机制已在红细胞5和某些物种的神经元6 -8中观察到。在这里，我给的结果研究的影响，离子电渗注入钙离子在心脏浦肯野细胞。这种注射导致膜超极化和相当大的动作电位缩短，表明细胞内游离Ca 2+的水平可以影响心肌中的钾渗透性。
ELEVATED extracellular Ca2+concentration1, prolonged treatment with high doses of cardiac glycosides2, and metabolic inhibition3shorten the action potential of cardiac muscle. In these conditions the intracellular free Ca2+may be increased and an increase in intracellular Ca2+could produce shortening of the action potential either by affecting the Ca2+inward current or by increasing the potassium permeability4. The latter mechanism has been observed in red blood cells5and in the neurones of some species6–8. Here I give the results of studying the effect of iontophoretically injected Ca2+in cardiac Purkinje cells. Such injection led to membrane hyperpolarisation and considerable shortening of the action potential, suggesting that the level of intracellular free Ca2+can affect the potassium permeability in cardiac muscle.