Sodium channel selectivity. Dependence on internal permeant ion concentration.
Sodium channel selectivity. Dependence on internal permeant ion concentration.
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钠通道的选择性。依赖内渗透离子浓度。
DOI：
10.1085/jgp.68.2.111
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发表时间：
1976-08
影响因子：
3.8
通讯作者：
Begenisich, T
中科院分区：
文献类型：
--
作者：
Cahalan, M;Begenisich, T
在鱿鱼轴突膜钠通道的选择性进行了研究与广泛变化的浓度的内部离子。的选择性比，PNa/PK，确定从反转电位从12.8下降到5.7至3.5，作为内部钾的浓度从530至180至50 mM，分别。内部KF灌注介质可以用四甲基铵（TMA）、Tris或蔗糖溶液稀释，PNa/PK降低相同。选择性比的变化取决于内部渗透离子浓度，而不是离子强度，膜电位，或氯离子渗透性。降低铯、铷、胍或铵的内部浓度也会降低PNa/Pion。钠通道的选择性顺序是：Na大于胍大于铵大于K大于Rb大于Cs。
The selectivity of sodium channels in squid axon membranes was investigated with widely varying concentrations of internal ions. The selectivity ratio, PNa/PK, determined from reversal potentials decreases from 12.8 to 5.7 to 3.5 as the concentration of internal potassium is reduced from 530 to 180 to 50 mM, respectively. The internal KF perfusion medium can be diluted by tetramethylammonium (TMA), Tris, or sucrose solutions with the same decrease in PNa/PK. The changes in the selectivity ratio depend upon internal permeant ion concentration rather than ionic strength, membrane potential, or chloride permeability. Lowering the internal concentration of cesium, rubidium, guanidnium, or ammonium also reduces PNa/Pion. The selective sequence of the sodium channel is: Na greater than guanidinium greater than ammonium greater than K greater than Rb greater than Cs.