DIFFERENTIAL-EFFECTS OF KINDLED AND ELECTRICALLY INDUCED SEIZURES ON A GLUTAMATE RECEPTOR (GLUR1) GENE-EXPRESSION

To address the question of whether the mode of seizure induction contr ibutes to the effects of seizures on glutamate receptor gene expressio n, we examined rat dorsal hippocampal slides by in situ hybridization after kindling by electrical stimulation of the amygdala. or after ele ctrically induced tonic-clonic seizures. Levels of a glutamate recepto r subtype (GluR1) mRNA were analyzed at three periods post kindled sei zures and found to be decreased only in brains that were obtained 24 h after the last kindled seizure. This downregulation of GluR1 mRNA was transient and was observed only in animals that had behavioral manife stations after being electrically stimulated. It is probable that main tenance of the kindled state cannot be explained by a long-lasting cha nge in GluR1 gene expression. Repeated electroshock-induced seizures i ncreased GluR1 mRNA levels in the hippocampus. Our results show that m ode of induction is an important determinant of the effects of seizure s on the levels of expression of a glutamate receptor gene.