SIGNALS THAT REGULATE ASTROGLIAL GENE-EXPRESSION - INDUCTION OF GFAP MESSENGER-RNA FOLLOWING SEIZURES OR INJURY IS BLOCKED BY PROTEIN-SYNTHESIS INHIBITORS

Previous studies have revealed that a single electroconvulsive seizure (ECS) strongly induces glial fibrillary acidic protein (GFAP) express ion in astrocytes in the hippocampal dentate gyrus. The signals that t rigger this induction are not known, but circumstantial evidence sugge sts the hypothesis that GFAP expression may be induced as a result of the induction of growth factor expression by dentate granule cells tha t also occurs as a result of the ECS and other types of seizures. The present study tests one prediction of this hypothesis by evaluating wh ether increases in GFAP mRNA levels after ECS are blocked by inhibitin g protein synthesis at various times after the ECS. We report that the upregulation of GFAP expression following ECS is blocked by protein s ynthesis inhibitors given 5 min before or up to 12 h after a single EC S. This temporal gradient suggests an intermediate step involving the increased expression of a protein growth factor. (C) 1997 Academic Pre ss.