Volume regulation in nih3t3 fibroblasts non expressing p
-glycoprotein. i. regulatory volume decrease.
Pasantes-Morales, H., R. S[acute]anchez Olea, D. Miranda, and J.
Mor[acute]an.
Institute of Cell Physiology, National University of Mexico, Mexico
City, Mexico
APStracts 3:0351C, 1996.
Exposure of NIH3T3 fibroblasts not expressing P-glycoprotein (PG) to
50%, 30%, 20% and 10% hyposmotic solutions led to cell volume
increases of 70%, 32%, 21% and 12%, respectively. After swelling,
NIH3T3 cells exhibited volume regulatory decrease (RVD) attaining
complete volume recovery after 30 min, except in 50% hyposmotic
solution in which volume recovery was 76%. RVD was accelerated by
gramicidin and inhibited by the Cl channel blockers 5-nitro-2-(3
-phenylpropylamino)benzoic acid (NPPB), 1,9,dideoxyforskolin (DDF),
dipyridamole and niflumic acid and by the K channel blocker
quinidine. RVD was 15% reduced by removal of extracellular Ca. The
pathway opened by hypotonicity was highly permeable to K and Rb and
only partly permeable to other cations. Most anions were permeable
with the following permeability rank: nitrate> benzoate =
iodide> thiocyanate> Cl>> gluconate. The
pathway was permeable to neutral amino acids : glycine>
alanine> glutamate> taurine > GABA>
glutamine. Basic amino acids were not permeable. These results show
that despite the absence of PG, NIH3T3 cells exhibit RVD with
properties similar to those expressed in most cell types.
Received 16 April 1996; accepted in final form 11 October 1996.
APS Manuscript Number C207-6.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 13 November 1996