Adrenal steroids and extinction behavior: Antagonism by progesterone, deoxycorticosterone and dexamethasone of a specific effect of corticosterone

Abstract

Extinction behavior was nearly absent in rats adrenalectomized one hour prior to forced extinction of a passive avoidance response. A low dose of corticosterone administered immediately after adrenalectomy normalized extinction behavior. Progesterone, 11-deoxycorticosterone and the synthetic glucocorticoid dexamethasone were not effective at the same or ten times higher doses. Instead, pre-treatment with these steroids prevented the normalizing effect of corticosterone on extinction behavior. These characteristics of steroid effects on behavior correspond to the strict specificity of the corticosterone receptor system in hippocampal neurons. The agonist or antagonist interaction of naturally occurring adrenal steroids with brain cells may serve behavioral adaptation.