Glucocorticoid receptor agonist and antagonist administration into the basolateral but not central amygdala modulates memory storage

The present study examined the effects, in male Sprague-Dawley rats, of microinfusion of drugs affecting glucocorticoid receptors (GRs or Type II) administered into either the basolateral (BLA) or central nucleus of the amygdala (CEA) on memory for training in an inhibitory avoidance and water-maze escape task. The specific GR agonist RU 28362 (1.0 or 3.0 ng) infused into the BLA immediately after training in a one-trial inhibitory avoidance task dose-dependently enhanced 48-h retention, whereas infusion of the GR agonist into the CEA did not affect retention. Additionally, pretraining microinfusions of the specific GR antagonist RU 38486 (0.3, 1.0, or 3.0 ng) into the BLA, but not infusions into the CEA, impaired memory for escape training to find a submerged platform in a water maze. These findings indicate that glucocorticoids affect memory storage, at least in part, by binding directly to GRs in the BLA and provide further evidence for the view that the BLA is an important brain region in integrating hormonal and neurotransmitter influences on memory storage. (C) 1997 Academic Press.