ENaC inhibition stimulates HCl secretion in the mouse cortical collecting duct. I. Stilbene-sensitive Cl- secretion.
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.
Department of Medicine, Emory University School of Medicine, Atlanta, Georgia;
Masayoshi
M
Nanami
Department of Medicine, Emory University School of Medicine, Atlanta, Georgia;
Yoskaly
Y
Lazo-Fernandez
Department of Medicine, Emory University School of Medicine, Atlanta, Georgia;
Vladimir
V
Pech
Department of Medicine, The University of Florida, Gainesville, Florida.
Jill W
JW
Verlander
Department of Medicine, Emory University School of Medicine, Atlanta, Georgia;
Diana
D
Agazatian
Department of Physiology and Biophysics, Weill Medical College of Cornell University, Ithaca, New York; Department of Medicine, Weill Medical College of Cornell University, Ithaca, New York; and.
Alan M
AM
Weinstein
Department of Physiology, Emory University School of Medicine, Atlanta, Georgia;
Hui-Fang
HF
Bao
Department of Physiology, Emory University School of Medicine, Atlanta, Georgia;
Douglas C
DC
Eaton
Department of Medicine, Emory University School of Medicine, Atlanta, Georgia; Department of Physiology, Emory University School of Medicine, Atlanta, Georgia; smwall@emory.edu.
Susan M
SM
Wall
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000465:Algorithms; D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D002462:Cell Membrane / Q000187:drug effects; D002712:Chlorides / Q000378:metabolism*; D004232:Diuretics / Q000494:pharmacology; D053503:Epithelial Sodium Channels / Q000235:genetics; D005260:Female; D006851:Hydrochloric Acid / Q000378:metabolism*; D007685:Kidney Tubules, Collecting / Q000378:metabolism*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D026941:Sodium Channel Blockers / Q000494:pharmacology*
D002712:Chlorides; D004232:Diuretics; D053503:Epithelial Sodium Channels; D026941:Sodium Channel Blockers; D000584:Amiloride; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D006851:Hydrochloric Acid
H+-ATPase; channels; chloride; epithelial sodium channel; pendrin