Anion channel blockers inhibit swelling-activated anion, cation and
nonelectrolyte transport in hela cells.
Hall, James A., Julie Kirk, Jennifer R. Potts, Caroline Rae, and
Kiaran Kirk.
University Laboratory of Physiology, Parks Rd, Oxford, OX1 3PT,
U.K., Department of Biochemistry, University of Oxford, South Parks
Rd, Oxford OX1 3QU, U.K. and Division of Biochemistry and Molecular
Biology, Faculty of Science, Australian National University, A.C.T.
0200, Australia
APStracts 3:0101C, 1996.
The effect of osmotic cell swelling on the permeability of HeLa cells
to a range of structurally unrelated solutes including taurine,
sorbitol, thymidine, choline and K+(86Rb+) was investigated. For each
solute tested, reduction in the osmolality of the medium from 300 to
200 mOsm(kg H2O)-1 caused a significant increase in the
unidirectional influx rate. In each case the osmotically-activated
transport component was nonsaturable up to external substrate
concentrations of 50 mM. Inhibitors of the swelling-activated anion
channel of HeLa cells (quinine, 4,4'-diisothiocyanatostilbene-2,2'
-disulfonic acid, niflumate, 1,9-dideoxyforskolin, 5-nitro-2-(3
-phenylpropylamino)benzoic acid and tamoxifen) blocked the
osmotically-activated influx of each of the different substrates
tested, as well as the osmotically-activated efflux of taurine and I
-. Tamoxifen and NPPB were similarly effective at blocking the
osmotically-activated efflux of 86Rb+. The simplest of several
hypotheses consistent with the data is that the osmotically-activated
transport of the different solutes tested here is via a swelling
-activated anion-selective channel that has a significant cation
permeability and a minimum pore diameter of 8-9 .
Received 22 January 1996; accepted in final form 22 March 1996.
APS Manuscript Number C43-6.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 16 April 96