AJP - Cell Physiology, Vol 258, Issue 6 C1169-C1172, Copyright © 1990 by American Physiological Society
Voltage-activated cation permeability in high-potassium but not low-potassium red blood cells
J. A. Halperin, C. Brugnara, T. Van Ha and D. C. Tosteson
Department of Cellular and Molecular Physiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
We have recently reported that voltage-activated fluxes of Na, K, and Ca
occur in human red blood cells [J.A. Halperin, C. Brugnara, M. Tosteson, T.
Van Ha, and D. C. Tosteson. Am. J. Physiol. 257 (Cell Physiol. 26):
C986-C996, 1989]. The cation permeability increases progressively as the
membrane potential becomes more inside positive above +20 mV. In this paper
we show that this effect also occurs in high-potassium (HK), but not in
low-potassium (LK), sheep and dog red blood cells. This result suggests
that the voltage-activated cation transport pathway is not the result of
nonspecific dielectric breakdown of the lipid bilayer but, rather, relates
to some membrane component, presumably a protein, that is expressed in HK
human and sheep but not in LK sheep and dog red blood cells.
