Chloride channels in the apical membrane of a distal nephron A6 cell line.
Chloride channels in the apical membrane of a distal nephron A6 cell line.
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远端肾单位 A6 细胞系顶膜中的氯离子通道。
DOI：
10.1152/ajpcell.1990.258.2.c352
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Eaton,DC
中科院分区：
文献类型：
--
作者：
Marunaka,Y;Eaton,DC
在本报告中，使用单通道记录方法来确定在培养的肾远端肾单位细胞（A6）的顶膜中是否存在Cl-传导通路。观察到两种不同类型的单Cl-通道。在细胞附着的贴片中，一个的单位电导为3 pS，而另一个的单位电导为8 pS。在细胞附着的补丁，与3 pS Cl-通道向外整流的电流，而8 pS Cl-通道的电流电压关系是线性的。3-pS Cl-通道有一个开放状态和一个关闭状态; 8-pS Cl-通道有一个开放状态和两个关闭状态。3-pS Cl-通道的开放概率是电压依赖性的（随着膜的去极化而增加），但即使在非常去极化的电位（+140 mV）下仍然很小（总是小于0.1）。另一方面，8-pS Cl-通道的开放概率较大（约0.8），且与电压无关。当贴片膜去极化时，3-pS Cl-通道的关闭率降低，而打开率增加。相反，8-pS Cl-通道的关闭率随去极化而降低，但开放率与电压无关。当细胞内表面存在高钙浓度（10-800 μ M）时，3-pS通道的外向整流在由内而外的贴片中显著减少。3-pS Cl-通道的开放概率通过腺苷3 '，5'-环一磷酸的膜渗透性类似物增加，主要是通过减少平均关闭时间。
In this report, single-channel recording methods were used to determine whether there are Cl- conductive pathways in the apical membrane of cultured renal distal nephron cells (A6). Two different types of single Cl- channels were observed. In cell-attached patches, one had a unit conductance of 3 pS, whereas the unit conductance of the other was 8 pS. In cell-attached patches, the currents associated with the 3-pS Cl- channel outwardly rectified, whereas the current voltage relationship for the 8-pS Cl-channel was linear. The 3-pS Cl- channel has one open and one closed state; the 8-pS Cl- channel has one open and two closed states. The open probability of the 3-pS Cl- channel was voltage dependent (increasing with depolarization of the membrane) but even at very depolarized potentials (+140 mV) remained small (always less than 0.1). On the other hand, the open probability of the 8-pS Cl- channel was large (approximately 0.8) and voltage independent. The closing rate of the 3-pS Cl- channel was decreased when the patch membrane was depolarized, whereas the opening rate was increased. In contrast, the closing rate of the 8-pS Cl- channel decreased with depolarization, but the opening rates were voltage independent. The outward rectification of the 3-pS channel was markedly reduced in inside-out patches when high calcium concentrations (10-800 microM) were present on the intracellular surface. The open probability of the 3-pS Cl- channel is increased by membrane permeable analogues of adenosine 3',5'-cyclic monophosphate primarily by decreasing the mean closed time.