Permeation, selectivity, and blockade of the Ca2+-activated potassium channel of the guinea pig taenia coli myocyte.
Permeation, selectivity, and blockade of the Ca2+-activated potassium channel of the guinea pig taenia coli myocyte.
复制标题
豚鼠大肠杆菌心肌的Ca2+活化的钾通道的渗透，选择性和阻塞。
DOI：
10.1085/jgp.94.5.849
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发表时间：
1989-11
期刊：
影响因子：
--
通讯作者：
Kao CY
中科院分区：
文献类型：
--
作者：
Hu SL;Yamamoto Y;Kao CY
结肠带肌细胞的147-pS Ca ~（2+）激活的K ~+通道的渗透特性与其他可兴奋膜中的延迟整流通道的渗透特性相似。其选择性顺序为K+ 1.0大于Rb+ 0.65大于NH 4 + 0.50。Na+、Cs+、Li+和TEA+（四乙基铵）是不渗透的。内部Na+以强烈的电压依赖性方式阻断K+通道，等效化合价（zd）为1.20。封锁由内部Cs+和TEA+是较少的电压依赖性，与0.61和0.13的d，和88和31 mM的半阻断浓度，分别。外部TEA+在阻断K+通道方面的有效性约为100倍。所有这些结果表明，在带肌细胞的147-pS Ca ~（2+）激活的K ~+通道，其生理功能类似于延迟整流器，是动作电位中复极电流的单通道基础。
The permeation properties of the 147-pS Ca2+-activated K+ channel of the taenia coli myocytes are similar to those of the delayed rectifier channel in other excitable membranes. It has a selectivity sequence of K+ 1.0 greater than Rb+ 0.65 greater than NH4+ 0.50. Na+, Cs+, Li+, and TEA+ (tetraethylammonium) are impermeant. Internal Na+ blocks K+ channel in a strongly voltage-dependent manner with an equivalent valence (zd) of 1.20. Blockade by internal Cs+ and TEA+ is less voltage dependent, with d of 0.61 and 0.13, and half-blockage concentrations of 88 and 31 mM, respectively. External TEA+ is about 100 times more effective in blocking the K+ channel. All these findings suggest that the 147-pS Ca2+-activated K+ channel in the taenia myocytes, which functions physiologically like the delayed rectifier, is the single- channel basis of the repolarizing current in an action potential.