Effects of deoxycorticosterone acetate and diazepam on neuropeptidergic neurons in rat striatum

The neurosteroid tetrahydrodeoxycorticosterone (THDOC) interacts with gamma-aminobutyric acid (GABA)/ benzodiazepine (BZ) receptors. To test the hypothesis that THDOC works partially through mechanisms associated with GABAA/BZ receptor function, deoxycorticosterone acetate (DOCA) and the benzodiazepine, diazepam (DZ), were administered short- (1 day) and long-term (11 days). Levels of mRNA for dynorphin, preprotachykinin and preproenkephalin in the striatum of adult male Sprague-Dawley rats were measured by in situ hybridization. Acute DOCA and DZ treatment produced parallel neuropeptide mRNA profiles, whereas chronic DOCA and DZ treatment yielded different patterns of neuropeptide gene expression. Chronic DZ treatment resulted in no significant increase in salt intake whereas chronic DOCA activated salt appetite. We suggest that acute DZ and DOCA interact with GABAA/BZ receptors; however, the results of chronic treatment suggest that DZ and DOCA operate through dissimilar mechanisms.