Outward current in single smooth muscle cells of the guinea pig taenia coli.
Outward current in single smooth muscle cells of the guinea pig taenia coli.
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DOI：
10.1085/jgp.93.3.551
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发表时间：
1989-03
期刊：
影响因子：
--
通讯作者：
Kao CY
中科院分区：
文献类型：
--
作者：
Yamamoto Y;Hu SL;Kao CY
在用酶消化分散的豚鼠结肠带绦虫单个肌细胞中，晚期外向电流由K+携带。它既有一个钙激活的成分，也有一个电压依赖的成分，可以抵抗外部的CO2+。其翻转电位为-84 mV，其通道(S)对K+具有高度选择性。在33℃时，激活遵循氮气动力学，在0 mV时的电压依赖时间常数为10.6ms，在+70 mV时缩短到1.7ms。失活遵循单指数时间过程，在-50 mV时与电压有关的时间常数为11 ms，在-20 mV时延长到33 ms。在4.5-S维持去极化的过程中，IK失活，大部分成两个指数分量，但有少量非失活残留物。据推测，在生理条件下的动作电位中，存在足够的Ik来引起复极。
In single myocytes of the guinea pig taenia coli, dispersed by enzymatic digestion, the late outward current is carried by K+. It has both a Ca2+-activated component and a voltage-dependent component which is resistant to external Co2+. The reversal potential is -84 mV, and the channel(s) for it are highly selective to K+. At 33 degrees C, the activation follows n2 kinetics, with a voltage-dependent time constant of 10.6 ms at 0 mV, which shortens to 1.7 ms at +70 mV. Deactivation follows a single-exponential time course, with a voltage-dependent time constant of 11 ms at -50 mV, which lengthens to 33 ms at -20 mV. During a 4.5-s maintained depolarization, IK inactivates, most of it into two exponential components, but there is a small noninactivating residue. It is surmised that during an action potential under physiological conditions, there is sufficient IK to cause repolarization.