Entral Mineralocorticoid Receptors Are Indispensable or Corticosterone-induced Impairment of Memory Etrieval in Rats

bstract—Previous studies indicated that stress levels of lucocorticoid hormones (cortisol in humans, and corticosteone in rodents) induce impairment of long-term memory etrieval, but the underlying mechanisms (genomic or nonenomic) are not clear. To clarify this issue, we investigated he involvement of brain corticosteroid receptors and protein ynthesis in the corticosterone-induced impairment of memry retrieval. Young rats were trained in the water maze task ith six trials per day for 6 consecutive days. Retention of the patial training was assessed 24 h after the last training ession with a 60-s probe trial. Experiments included intraentricular injections of anisomycin, a specific protein synhesis inhibitor or specific antagonists for both types of coricocosteroid receptors (mineralocorticoid receptor, MR, and lucocorticoids receptor, GR) before corticosterone adminstration shortly before retention testing. The results showed hat administration of anisomycin did not change the cortiosterone response. Administration of the MR, but not GR, ntagonist blocked the corticosterone-induced response ose dependently. These findings provide evidence for the iew that glucocorticoids impair memory retrieval through ongenomic mechanisms involving an interaction with cenral MRs. © 2007 IBRO. Published by Elsevier Ltd. All rights eserved.