脊椎动物交感神经元中的钙激活钾电流。

Ca-activated potassium current in vertebrate sympathetic neurons.

作者信息

Brown D A, Constanti A, Adams P R

出版信息

Cell Calcium. 1983 Dec;4(5-6):407-20. doi: 10.1016/0143-4160(83)90017-9.

Abstract

Ca-activated K-currents (IC) in sympathetic neurones have been triggered by intracellular Ca-injection or by activating ICa. IC is strongly voltage-dependent, with a peak slope of 11 mV/e-fold depolarization above -50 mV. Relaxation, fluctuation and single channel analysis suggests this to result from voltage-dependent opening and closing rates. Time-constants for channel opening and closing are about 15 msec near zero mV. Single channel conductance is about 100 pS. Currents can be blocked by TEA. IC is activated very rapidly (less than or equal to 5 msec) and sometimes transiently by a depolarizing voltage-step. It is suggested that IC contributes to both spike repolarization and spike after-hyperpolarization. Spontaneous miniature ICs have also been recorded, probably activated by the release of packets of intracellular Ca.

摘要

交感神经元中的钙激活钾电流（IC）可通过细胞内钙注射或激活ICa来触发。IC具有强烈的电压依赖性，在-50 mV以上时，其峰值斜率为11 mV/十倍去极化。松弛、波动和单通道分析表明，这是由电压依赖性的开放和关闭速率导致的。在接近零mV时，通道开放和关闭的时间常数约为15毫秒。单通道电导约为100 pS。电流可被TEA阻断。IC可被去极化电压阶跃非常快速地激活（小于或等于5毫秒），有时是短暂激活。有人认为，IC对动作电位复极化和动作电位后超极化均有贡献。也记录到了自发的微小IC，可能是由细胞内钙包的释放所激活。