Pathways for k+ transport across the bovine articular chondrocyte
membrane and their sensitivity to cell volume.
Hall, Andrew C., Ian Starks, Clare L. Shoults, and Saideh Rashidbigi.
University Laboratory of Physiology, Parks Road, Oxford, OX1 3PT,
U.K.
APStracts 2:0414C, 1995.
The contributions of various K+ transport pathways in bovine
chondrocytes isolated from articular cartilage and their responses to
changes in cell volume have been studied. K+(86Rb) uptake mediated by
the Na+/K+ pump and Na+/K+/2Cl- cotransporter were stimulated by cell
shrinkage, the latter as part of the RVI response, the former as an
indirect effect resulting from the rise in [Na+]i during RVI. For
both transporters, there was an increase in the Vmax with no
detectable effect on the Km. There was no evidence for volume
-sensitive K+ transport mediated by the K+/Cl- cotransporter, or Ca2+
-activated K+ channels. However chondrocyte swelling stimulated a
ouabain and bumetanide-insensitive K+ flux sensitive to pimozide and
other drugs, which exhibited some of the properties of the relatively
non-specific volume-sensitive `osmolyte' channel described in other
cell types.
Received 22 May 1995; accepted in final form 16 November 1995.
APS Manuscript Number C293-5.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 8 December 95