Hippocampal gene expression in the pig: upregulation of corticotrophin releasing hormone mRNA following central administration of the peptide

Corticotrophin releasing hormone (CRH) and glucocorticoids affect hypophysi otrophic regions of the brain and influence limbic system activity. Since t he latter mediates emotional responses, changes in gene expression in regio ns such as the hippocampus may provide new information on neural stress mec hanisms. In this study, mRNA for CRH and selected ionotropic glutamate rece ptor (iGluR) subunits (NR1, GluR2, GluR3) was quantified in the hippocampus of pigs in which stress was simulated by central administration of CRH (10 0 mug). Increases in hippocampal CRH mRNA were detected in the CA3 subfield 4 h later, and in the CAI, CA2 and CA3 subfields 24 h post-treatment. Howe ver, there were no associated changes in iGluR subunit mRNAs, although the ratio GluR3: GluR2 increased in the dentate gyrus after 4 h. These results, together with a recent similar finding in rats subjected to restraint, poi nt to an involvement of hippocampal CRH in the neuronal response to stress. (C) 2000 Harcourt Publishers Ltd.