Changes of the actin cytoskeleton during swelling and volume
regulatory decrease in cultured astrocytes.
Mor[acute]an, J., M. Sabanero, I. Meza, and H. Pasantes-Morales.
Instituto de Fisiolog[acute]ia Celular, Universidad Nacional A. de
M[acute]exico, Departamento de Biolog[acute]ia Celular, Centro de
Investigaci[acute]on y de Estudios Avanzados, del IPN, M[acute]exico
DF, Instituto de Biolog[acute]ia Experimental, Universidad de
Guanajuato, Mexico
APStracts 3:0256C, 1996.
Swelling of cultured astrocytes exposed to hyposmotic medium modified
the organization of the F-actin cytoskeleton making the actin network
diffuse in the cell body but concentrated at foci corresponding to
the tips of the cell projections retracted by swelling. This change
was reversible and after 2 h the actin cytoskeleton tended to recover
and cells regained their flat and stellate shape. Cytochalasins B and
D (CB and CD), which disrupt the actin cytoskeleton did not affect
RVD nor the swelling activated efflux of Cl and inositol although CD
10 [mu]M increased the basal efflux of taurine. The mercurial p
-chloro mercuribenzenesulfonate (0.5-1 mM), known to disrupt the
membrane cytoskeleton in isosmotic conditions induced a 46%, 50% and
38% release of [3H]taurine, 125I and [3H]inositol, respectively,
causing cell shrinkage and retraction of the cytoskeleton.
Coincidently, the swelling-stimulated release of [3H]taurine and 125I
was reduced by 60% and 30%, respectively. Results of this study do
not exclude the possibility that changes in the actin cytoskeleton
elicited by swelling are involved in mechanisms of RVD and only
indicate that the disruption caused by cytochalasins is unrelated to
that process.
Received 29 January 1996; accepted in final form 6 June 1996.
APS Manuscript Number C56-6.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 21 August 1996