Modulation of hippocampal glucocorticoid and mineralocorticoid receptor mRNA expression by amygdaloid kindling.

In situ hybridization was used to examine the effects of amygdala kindling on the expression of mRNAs for mineralocorticoid receptors (MR) and glucocorticoid receptors (GR) in the rat hippocampus. Kindling increased 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 significantly increased only at the 4-hour time point. Kindling also increased the levels of GR mRNA in the dentate gyrus at 4 h; however, GR mRNA levels significantly decreased below control values at 24 h before returning to normal at 4 days. These data indicate differential transient alterations in hippocampal MR and GR receptor mRNA expression following amygdala-kindled seizures.