AMILORIDE-SENSITIVE NA CHANNELS FROM THE APICAL MEMBRANE OF THE RAT CORTICAL COLLECTING TUBULE
AMILORIDE-SENSITIVE NA CHANNELS FROM THE APICAL MEMBRANE OF THE RAT CORTICAL COLLECTING TUBULE
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DOI：
10.1073/pnas.83.8.2767
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发表时间：
1986-04-01
影响因子：
11.1
通讯作者：
FRINDT, G
中科院分区：
文献类型：
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作者：
PALMER, LG;FRINDT, G
采用膜片钳技术研究了大鼠皮质集合小管顶膜单个钠通道电流。在细胞附着的补丁，通道具有5 pS的电导与140 mM的NaCl在移液管。电导是外部Na的饱和函数，最大值约为8 pS，在约75 mM Na时达到半饱和。在切除的内面向外的补丁，通道的选择性Na超过K估计从逆转电位至少为10：1。通道在开放和关闭状态之间进行自发转换。两种状态的平均寿命均为3-4秒。向移液管中加入阿米洛利（0.5 μ M）诱导通道更频繁的关闭和打开以及平均开放时间的减少。推测这些通道在体内介导该肾单位段的Na重吸收。
Currents through individual Na channels in the apical membrane of the rat cortical collecting tubule were resolved by using the patch-clamp technique. In cell-attached patches, the channels had a conductance of 5 pS with 140 mM NaCl in the pipet. The conductance was a saturable function of external Na, with a maximal value of about 8 pS and a half saturation at about 75 mM Na. In excised inside-out patches, the selectivity of the channels for Na over K was estimated from reversal potentials to be at least 10:1. The channels underwent spontaneous transitions between open and closed states. Both states had mean lifetimes of 3-4 sec. Amiloride (0.5 .mu.M) added to the pipet induced more frequent closures and openings of the channels and a reduction in the mean open time. These channels are presumed to mediate Na reabsorption by this nephron segment in vivo.