Neurotransmitter modulation of glucocorticoid receptor mRNA levels in the rat hippocampus.

Glucocorticoids in the hippocampus mediate adaptive responses elicited by stressful stimuli. In this study we investigated glucocorticoid receptor gene expression in the rat hippocampus following acute stress. A significant decrease in glucocorticoid receptor mRNA levels was observed in the hippocampus less than 1 h after the onset of stress. This decrease was inhibited by administering either MK-801, diazepam or propranolol prior to exposure to stress. The effect of diazepam on the stress-induced decrease in hippocampal glucocorticoid receptor mRNA was reversed by Ro-15-1788, suggesting that it is mediated by central benzodiazepine receptors, i.e. GABA-A. These results indicate that NMDA, GABA-A and β-adrenergic receptors are involved in the mechanism of the stress-induced decrease in glucocorticoid receptor mRNA levels in the rat hippocampus.