NEGATIVE AFTER-POTENTIAL OF FROGS SKELETAL MUSCLE
NEGATIVE AFTER-POTENTIAL OF FROGS SKELETAL MUSCLE
复制标题
DOI：
10.1152/jn.1957.20.6.602
复制
发表时间：
1957-01-01
影响因子：
2.5
通讯作者：
FRANK, GB
中科院分区：
文献类型：
--
作者：
FRANK, GB
在细胞内微电极上，负后电位的幅值与静息电位的幅值呈线性关系。改变外源Na+浓度、增加外源K+浓度或适度的藜芦碱处理均不改变这种关系。外源K+浓度的大幅降低或在林格氏液或低K+溶液中浸泡时间的延长会使其发生紊乱。发现负后电位的下降呈指数级，其时间常数（[tau]m）与外加超极化的下降相似。结果支持这样的观点，即动作电位的快速复极化阶段以膜轻微去极化结束，负后电位是膜电位被动返回到静息水平。还有证据表明Na电导率略高于静息水平。由这种情况引起的Na+向内运动的增加稍微减慢了复极。
When investigated with inside-the-cell micro-electrodes, a linear relation was found between the amplitude of the negative after-potential and the resting potential. This relation was not altered by changing the external Na+ concentration, increasing the external K+ concentration or moderate veratrine treatment. It was upset by great reduction of the external K+ concentration or prolonged soaking in Ringer''s or low K+ solutions. The decline of the negative after-potential was found to be exponential and its time constant ([tau]m) was similar to that for the decline of an impressed hyperpolarization. Results support the view that the rapid repolarization phase of the action potential ends with the membrane slightly depolarized and the negative after-potential is a passive return of the membrane potential back to resting levels. There was also evidence indicating a slight increase in the Na conductivity over resting levels. The increased inward movement of Na+ which results from this condition slightly slows down the repolarization.