EXPRESSION OF GABA(A) RECEPTORS BY REACTIVE ASTROCYTES IN EXPLANT ANDPRIMARY CULTURES OF RAT CNS

The presence of GABA(A)-receptors on astrocytes was studied in explant and primary cultures of rat cerebellum, hippocampus and spinal cord b y means of immunohistochemistry. For these studies we have used the mo noclonal antibody bd 17 against the beta(2)- and beta(2)-subunits of G ABA(A)-receptor. In explant cultures many neurones were intensely stai ned with the GABA(A)-receptor antibody whereas adjacent astrocytes rev ealed little or no immunoreactivity. In the far outgrowth zone of expl ant culture, however, many immunostained astrocytes were observed. In primary astrocyte cultures, only a few cells were stained by the antib ody. Astrocytes which became reactive after producing an artificial sc ar or after addition of certain compounds such as dibutyryl cyclic AMP , interleukin-6, basic fibroblast growth factor and kainic acid, also revealed GABA(A)-receptor immunoreactivity. Furthermore, these astrocy tes were intensely stained for glial fibrillary acidic protein and vim entin. From our studies we conclude that only a subpopulation of norma l astrocytes are immunopositive for the GABA(A)-receptor antibody wher eas astrocytes which become reactive following injury of the tissue or after addition of dibutyryl cyclic AMP, the cytokine interleukin-6, f ibroblast growth factor or the neurotoxin kainic acid express GABAA-si tes. (C) 1997 ISDN. Published by Elsevier Science Ltd. All rights rese rved.