无氯介质中蛙胃黏膜分泌膜的离子通道

Ionic pathways of secretory membrane of frog gastric mucosa in Cl--free media.

作者信息

Holloman T L, Schwartz M, Dinno M A, Carrasquer G

出版信息

Am J Physiol. 1976 Dec;231(6):1649-54. doi: 10.1152/ajplegacy.1976.231.6.1649.

DOI:10.1152/ajplegacy.1976.231.6.1649

Abstract

Experiments were performed to determine the return ionic pathways of the secretory membrane of frog gastric mucosa associated with the electrogenic H+ pump in Cl--free media. The replacement of a 52 mM Na2SO4 secretory solution with a 52 mM K2SO4 secretory solution led to a decrease of resistance, an increase of the H+ secretory rate, and a reversal of the PD. The replacement of 52 mM Na2SO4 with 52 mM MgSO4 led to an increase of resistance and a decrease of the H+ rate. These results provided evidence for the existence of K+ and Na+ pathways, the former having a lower resistance than the latter. Short-circuiting the mucosa in Mg2+ solutions increased the H+ rate to the value in Na+ solutions, hence ruling out the possibility that Mg2+ might interfere with the H+ pump. The fact that the Mg2+ secretory solution, without K+ or Na+, did not abolish the H+ rate suggested the presence of at least a third ionic pathway. presumably SO42-, providing that Mg2+ does not penetrate the mucosa.

摘要

进行实验以确定蛙胃黏膜分泌膜与无氯介质中电生性H⁺泵相关的返回离子途径。用52 mM K₂SO₄分泌液替代52 mM Na₂SO₄分泌液导致电阻降低、H⁺分泌速率增加以及跨膜电位（PD）逆转。用52 mM MgSO₄替代52 mM Na₂SO₄导致电阻增加和H⁺速率降低。这些结果为K⁺和Na⁺途径的存在提供了证据，前者的电阻低于后者。在Mg²⁺溶液中使黏膜短路会使H⁺速率增加到Na⁺溶液中的值，因此排除了Mg²⁺可能干扰H⁺泵的可能性。不含K⁺或Na⁺的Mg²⁺分泌液并未消除H⁺速率这一事实表明至少存在第三条离子途径，推测为SO₄²⁻，前提是Mg²⁺不穿透黏膜。