HYPOKALEMIC PERIODIC PARALYSIS - INVITRO INVESTIGATION OF MUSCLE-FIBER MEMBRANE PARAMETERS
HYPOKALEMIC PERIODIC PARALYSIS - INVITRO INVESTIGATION OF MUSCLE-FIBER MEMBRANE PARAMETERS
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DOI：
10.1002/mus.880070205
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发表时间：
1984-01-01
期刊：
影响因子：
3.4
通讯作者：
KUTHER, G
中科院分区：
文献类型：
--
作者：
RUDEL, R;LEHMANNHORN, F;KUTHER, G
为了研究家族性低钾性麻痹的发病机制，我们记录了3例患者的静息膜电位、动作电位、电流-电压关系和肋间肌纤维的等长力。在正常细胞外液中，静息电位降低，但膜电导与对照组无差异。兴奋性降低，动作电位无超调。在暴露于1 mM钾溶液（含或不含胰岛素）时，细胞去极化至约-50 mV，并变得不可兴奋。在−120至−40 mV的测试膜电位范围内，1 mM钾溶液中的斜率电导与1 mM钾溶液中的对照纤维没有差异。特别是，钾组分电导没有降低。去极化纤维不能通过返回到3.5 mM钾溶液中完全复极化。实验诱导的氯离子平衡电位的瞬时位移到一个高度负的值引起稳定的复极。用非永久性阴离子替代细胞外氯离子也可以诱发麻痹，这种治疗会导致健康纤维的肌强直。得出的结论是，基本的缺陷是降低的兴奋性和增加的钠电导，并且这些缺陷在细胞外钾浓度降低时加重。
To study the mechanism of attacks in familial hypokalemic paralysis, we recorded resting membrane potentials, action potentials, current–voltage relationships, and isometric forces in intercostal muscle fibers from three patients. In normal extracellular medium, the resting potential was reduced, but membrane conductance was not different from control. Excitability was reduced and the action potentials had no overshoot. On exposure to a 1‐mMpotassium solution, with or without insulin, the cells depolarized to about −50 mV, and became inexcitable. Over the tested membrane potential range from −120 to −40 mV, the slope conductance in the 1‐mMpotassium solution was not different from that of control fibers in a 1‐mMpotassium solution. In particular, the potassium component conductance was not reduced. Depolarized fibers could not be completely repolarized by returning to a 3.5‐mMpotassium solution. An experimentally induced transient shift of the chloride equilibrium potential to a highly negative value caused stable repolarization. Paralysis could also be induced by replacement of extracellular chloride with an impermanent anion, a treatment which causes myotonia in healthy fibers. It was concluded that the basic defects are a reduced excitability and an increased sodium conductance, and that these defects are aggravated on reduction of the extracellular potassium concentration.