Referenced in: none

Automatically associated channels: ClC4 , ClC5

Title: ENaC inhibition stimulates HCl secretion in the mouse cortical collecting duct. I. Stilbene-sensitive Cl- secretion.

Authors: Masayoshi Nanami, Yoskaly Lazo-Fernandez, Vladimir Pech, Jill W Verlander, Diana Agazatian, Alan M Weinstein, Hui-Fang Bao, Douglas C Eaton, Susan M Wall

Journal, date & volume: Am. J. Physiol. Renal Physiol., 2015 Aug 1 , 309, F251-8

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/25925258

Abstract
Inhibition of the epithelial Na(+) channel (ENaC) reduces Cl(-) absorption in cortical collecting ducts (CCDs) from aldosterone-treated rats and mice. Since ENaC does not transport Cl(-), the purpose of the present study was to explore how ENaC modulates Cl(-) absorption in mouse CCDs perfused in vitro. Therefore, we measured transepithelial Cl(-) flux and transepithelial voltage in CCDs perfused in vitro taken from mice that consumed a NaCl-replete diet alone or the diet with aldosterone administered by minipump. We observed that application of an ENaC inhibitor [benzamil (3 μM)] to the luminal fluid unmasks conductive Cl(-) secretion. During ENaC blockade, this Cl(-) secretion fell with the application of a nonselective Cl(-) channel blocker [DIDS (100 μM)] to the perfusate. While single channel recordings of intercalated cell apical membranes in split-open CCDs demonstrated a Cl(-) channel with properties that resemble the ClC family of Cl(-) channels, ClC-5 is not the primary pathway for benzamil-sensitive Cl(-) flux. In conclusion, first, in CCDs from aldosterone-treated mice, most Cl(-) absorption is benzamil sensitive, and, second, benzamil application stimulates stilbene-sensitive conductive Cl(-) secretion, which occurs through a ClC-5-independent pathway.