Inhibition by polyunsaturated fatty acids of regulatory volume decrease and osmolyte fluxes in astrocytes in culture. R., S[acute]anchez-Olea, Morales-Mulia M., Mor[acute]an J. and Pasantes- Morales,h. Institute of Cell Physiology, National University of Mexico, Mexico City, Mexico.
APStracts 2:0072C, 1995.
The polyunsaturated fatty acids (PUFA), arachidonic (AA), linoleic and linolenic acids were potent blockers of RVD and of the swelling activated efflux of 3[H]-taurine, 3[H]-D-aspartate, 3[H]-inositol and 125I (used as marker of Cl) from rat cerebellar astrocytes in culture. The monounsaturated oleic and ricinoleic acids and saturated fatty acids were ineffective. The amino acid and 125I fluxes were similarly inhibited by fatty acids (FA) whereas inositol release was less sensitive. Polyunsaturated FA appear to directly affect RVD in trypsinized astrocytes as the inhibition was immediate and fully reversible. Blockers of the AA metabolic pathways, indomethacin (cyclooxygenase), esculetin (lypooxygenases) and metyrapone (P450 monooxygenases) did not prevent the effect of AA, suggesting that further metabolism is not required for displaying the effects of AA on RVD and osmolyte fluxes. Some blockers of AA metabolic pathways such as nordyhidroguaiaretic acid (lypooxygenases) and naphtoflavone (P450 monooxygenases) exhibited themselves marked inhibitory effects on RVD and on osmolyte fluxes. The predominant AA metabolite in astrocytes, 12-HETE did not affect RVD nor osmolyte fluxes. It is suggested form these results that AA and other PUFA directly inhibit the permeability pathways correcting cell volume after swelling in cultured astrocytes. 

Received 7 September 1994; accepted in final form 13 January 1995.
APS Manuscript Number C532-4.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 28 February 1995.