The flux ratio of the Na-Cl cotransport mechanism in the frog corneal epithelium

Publisher Website
Google Scholar
Abstract
The stoichianetry of the Na-Cl ootransport mechanism at the base-lateral membrane of the frog corneal epithelium was studied with the aid of intracellular microelectrodes by analyzing the effects of ouabain on intracellular recordings (PDSC) and transepithelial short-circuit current (ISC). Under short-circuit conditions, the total current across the basolateral membrane was equated to the Cl− transport across the apical membrane. Ouabain produces a quick and steep decrease of PDSC (7.1 mV) and ISC (3.0 μA/cm2) that was ascribed to a sudden inhibition of the electrogenic component of the Na-K pump. From these effects, and from results in previous studies, the maximum value for the Na+ flux via the ootransport mechanism (ICNa) was estimated and compared to the apical Cl− transport (a minimum estimate of the Cl− flux cotransported with Na+). In all experiments, Icl was larger than INa. Considering that Na+ also recirculates across tne basolateral membrane via a passive pathway, the Cl:Na flux ratio of the ootransport system may be as high as 4.

This publication has 8 references indexed in Scilit: