STRONG VOLTAGE-DEPENDENT INWARD RECTIFICATION OF INWARD RECTIFIER K+ CHANNELS IS CAUSED BY INTRACELLULAR SPERMINE
STRONG VOLTAGE-DEPENDENT INWARD RECTIFICATION OF INWARD RECTIFIER K+ CHANNELS IS CAUSED BY INTRACELLULAR SPERMINE
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DOI：
10.1016/0092-8674(95)90459-x
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发表时间：
1995-01-13
期刊：
影响因子：
64.5
通讯作者：
RUPPERSBERG, JP
中科院分区：
文献类型：
--
作者：
FAKLER, B;BRANDLE, U;RUPPERSBERG, JP
在许多类型的细胞中，内向整流钾通道调节静息电位下的K+电导。由于当细胞膜去极化超过触发阈值时，这些K+通道不会传递外向电流(内向整流)，因此它们在控制兴奋性方面发挥着重要作用。细胞内镁离子的高度电压依赖性阻断和内源性门控过程目前都被认为是欠内向整流。结果表明，在生理条件下发现的强烈的电压依赖性整流主要是由于细胞内精胺的作用。生理浓度的游离精胺介导了IRK1内向整流钾通道的强烈整流，即使在没有游离镁离子的情况下，在没有内源性整流的IRK1突变通道中也是如此。
Inward rectifier K+ channels mediate the K+ conductance at resting potential in many types of cell. Since these K+ channels do not pass outward currents (inward rectification) when the cell membrane is depolarized beyond a trigger threshold, they play an important role in controlling excitability. Both a highly voltage-dependent block by intracellular Mg2+ and an endogenous gating process are presently assumed to underly inward rectification. It is shown that strong voltage dependence of rectification found under physiological conditions is predominantly due to the effect of intracellular spermine. Physiological concentrations of free spermine mediate strong rectification of IRK1 inward rectifier K+ channels even in the absence of free Mg2+ and in IRK1 mutant channels that have no endogenous rectification.