MODULATION OF HIPPOCAMPAL GLUCOCORTICOID AND MINERALOCORTICOID RECEPTOR MESSENGER-RNA EXPRESSION BY AMYGDALOID KINDLING

In situ hybridization was used to examine the effects of amygdala kind ling on the expression of mRNAs for mineralocorticoid receptors (MR) a nd glucocorticoid receptors (GR) in the rat hippocampus. Kindling incr eased MR mRNA levels in the dentate gyrus of the hippocampus 4 h after the last seizure, and these levels remained elevated 24 h later, but returned to baseline at 4 days. The only other hippocampal region that showed changes was the ipsilateral CA2 subfield where MR mRNA was sig nificantly increased only at the 4-hour time point. Kindling also incr eased the levels of GR mRNA in the dentate gyrus at 4 h; however, GR m RNA levels significantly decreased below control values at 24 h before returning to normal at 4 days. These data indicate differential trans ient alterations in hippocampal MR and GR receptor mRNA expression fol lowing amygdala-kindled seizures.