central mineralocorticoid receptors mediate impairing effects of corticosterone on memory retrieval in rats

introduction: previous studies have indicated that stress levels of glucocorticoid hormones induce impairment of long term memory retrieval, but the underlying mechanisms (genomic or non-genomic) are not clear. to clarify this issue, we investigated the involvement of brain corticosteroid receptors and protein synthesis in the glucocorticoid-induced impairment of memory retrieval. methods: 140 young rats were trained in the water maze (wm) task with six trials per day for six consecutive days. retention of the spatial training was assessed 24 h after the last training session with a 60-s probe trial. experiments included intraventricular injections of anisomycin ( 187.5 or 450 µg/5µl) , a specific protein synthesis inhibitor or specific antagonists for mineralocorticoid receptors (mr, 37.5, 75, 150 µg/5ul) or glucocorticoids receptors (gr, 75 or 150 µg/5ul) before corticosterone administration (1 mg/kg) shortly before retention testing. results: the results showed that administration of anisomycin did not change the corticosterone response. administration of the mr, but not gr, antagonist blocked the corticosterone-induced response. conclusion: these findings provide evidence for the view that glucocorticoids impair memory retrieval through non-genomic mechanisms involving an interaction with central mrs.