INTRACELLULAR NA+ ACTIVATES A K+ CHANNEL IN MAMMALIAN CARDIAC-CELLS
INTRACELLULAR NA+ ACTIVATES A K+ CHANNEL IN MAMMALIAN CARDIAC-CELLS
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DOI：
10.1038/309354a0
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发表时间：
1984-01-01
期刊：
影响因子：
64.8
通讯作者：
IRISAWA, H
中科院分区：
文献类型：
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作者：
KAMEYAMA, M;KAKEI, M;IRISAWA, H
在多种细胞中，各种细胞内因子，例如 Ca2+（参考文献 1,2）、ATP3,4 和环核苷酸 5,6，调节膜的离子电导。在心肌细胞中，当生电 Na-K 泵活动或 Na-Ca 交换机制发生干扰时，细胞内 Na+ 浓度 ([Na+]i) 经常增加。我们使用膜片钳方法研究了 [Na+]i 在控制离子通道中的可能作用7，并发现了一个由 [Na+]i>20mM 门控的 K+ 通道，但不受细胞内 Ca2+ 浓度 (∼10−4M) 门控。我们在此报告，该通道的单位电导为 207 ± 19 pS(n= 16)，外部 K+ 浓度为 150 mM，内部为 49 mM，并且没有显示出可检测到的电压依赖性动力学。 Na+激活的K+通道代表了一类新型离子通道。
In a wide variety of cells, various intracellular agents, such as Ca2+(refs 1,2), ATP3,4and cyclic nucleotides5,6, regulate ionic conductances of the membrane. In cardiac cells, the intracellular Na+concentration ([Na+]i) frequently increases when a disturbance occurs in the electrogenic Na–K pump activity or the Na–Ca exchange mechanism. We have investigated a possible role of [Na+]iin controlling ion channels by using a patch-clamp method7, and have found a K+channel that is gated by [Na+]i>20mM, but not by the intracellular Ca2+concentration (∼10−4M). We report here that the channel has a unitary conductance of 207 ± 19 pS(n= 16) with K+concentrations of 150 mM outside and 49 mM inside, and shows no detectable voltage-dependent kinetics. The Na+-activated K+channel represents a novel class of ionic channel.