AJP - Gastrointestinal and Liver Physiology, Vol 262, Issue 6 1027-G1032, Copyright © 1992 by American Physiological Society

ARTICLES

Anion channels in rat liver canalicular plasma membranes reconstituted into planar lipid bilayers

M. Sellinger, S. A. Weinman, R. M. Henderson, A. Zweifach, J. L. Boyer and J. Graf
Department of Medicine, Yale University School of Medicine, New Haven, Connecticut 06510.

Previous studies from this laboratory have demonstrated a Cl(-)-HCO3- exchanger and have provided evidence for a Cl- conductance in rat liver canalicular plasma membrane vesicles. To further investigate the apical Cl- conductance, we performed single-channel analysis after incorporation of canalicular liver plasma membrane vesicles into planar lipid bilayers. This was necessary, because the canalicular membrane is not accessible for the patch-clamp technique. Two types of anion channels could be identified (30- and 90-pS conductance) corresponding to the class of small and intermediate channels, respectively. The kinetics of the small channel were found to be voltage dependent with a maximum for the open probability at -20 mV. In contrast, intermediate channel kinetics were voltage independent. The anion channels described above could allow electrogenic Cl- efflux, to compensate Cl- influx via the electroneutral Cl(-)-HCO3- exchanger. Further studies will be required to prove their functional importance in bile formation.

This article has been cited by other articles:

				K. Shimada, X. Li, G. Xu, D. E. Nowak, L. A. Showalter, and S. A. Weinman Expression and canalicular localization of two isoforms of the ClC-3 chloride channel from rat hepatocytes Am J Physiol Gastrointest Liver Physiol, August 1, 2000; 279(2): G268 - G276. [Abstract] [Full Text] [PDF]