AJP - Gastrointestinal and Liver Physiology, Vol 265, Issue 1 28-G34, Copyright © 1993 by American Physiological Society

ARTICLES

Potassium conductance in rabbit esophageal epithelium

W. E. Khalbuss, R. Alkiek, C. G. Marousis and R. C. Orlando
Department of Medicine, Tulane University School of Medicine, New Orleans, Louisiana.

K+ conductance in apical and basolateral cell membranes of rabbit esophageal epithelial cells was investigated within intact epithelium by impalement with conventional microelectrodes from luminal or serosal sides. Under steady-state conditions, K+ conductance was demonstrated in basolateral, but not apical, membranes by showing 1) membrane depolarization upon exposure to either solutions high in K+ (20-65 mM) or containing Ba2+, tetraethylammonium, or quinine, and 2) a resistance ratio that increased on exposure to high K+ solution and decreased on exposure to Ba2+, quinine, and tetraethylammonium. From exposures to high K+, the apparent K+ transference number and electromotive force generated at the basolateral membrane were calculated and found to be 0.42 +/- 0.01 and -83 +/- 3 mV, respectively. Furthermore, basolateral K+ conductance was shown to be important for maintaining resting net transepithelial Na+ absorption in that high K+ or barium inhibited the transepithelial potential difference and short-circuit current of Ussing-chambered epithelia. We conclude that under steady-state conditions the basolateral, but not apical, membranes of esophageal epithelial cells contain a K(+)-conductive pathway and that this pathway is important for active sodium absorption.

This article has been cited by other articles:

				N. A. Tobey, C. M. Argote, X. C. Vanegas, W. Barlow, and R. C. Orlando Electrical parameters and ion species for active transport in human esophageal stratified squamous epithelium and Barrett's specialized columnar epithelium Am J Physiol Gastrointest Liver Physiol, July 1, 2007; 293(1): G264 - G270. [Abstract] [Full Text] [PDF]

				S. Abdulnour-Nakhoul, N. L. Nakhoul, C. Caymaz-Bor, and R. C. Orlando Chloride transport in rabbit esophageal epithelial cells Am J Physiol Gastrointest Liver Physiol, April 1, 2002; 282(4): G663 - G675. [Abstract] [Full Text] [PDF]