Facilitation of ethanol consumption by intracerebroventricular infusions of corticosterone

Male Wistar rats bearing intracerebroventricular (ICV) cannulae and with simultaneous access to 6% ethanol and water were subjected to adrenalectomy (ADX) or sham surgery. ADX decreased ethanol intake. Starting a few days later, the animals received ICV infusions with 100 mu g corticosterone acetate (CORT) with 2-to 3-day intervals for 2 weeks. ICV CORT. but not SC CORT at the same dose, restored ethanol consumption in ADX rats to preoperative levels, whereas vehicle infusions (propylene glycol) did not. Adrenally intact animals, which normally consumed moderate amounts of ethanol (similar to 0.5 g/kg per day), also showed a robust effect of ICV infusions of CORT, whereas this facilitatory effect was not observed in high consumers (similar to 3.0 g/kg per day). The suppressive effect of ADX on ethanol intake was not reproduced by concurrent and repeated ICV infusions of intracellular mineralocorticoid (RU 28318) and glucocorticoid (mifepristone) receptor blockers. It is concluded that CORT stimulates alcohol consumption by acting in the brain, probably by way of neuronal membrane mechanisms.