Combined restraint and cold stress in rats: effects on memory processing in passive avoidance task and on plasma levels of ACTH and corticosterone.

摘要: The effect of restraint stress combined with water immersion (IMO+C), applied at various intervals before and after the acquisition a passive avoidance task, was studied in rats. procedure started two pre-training trials. On single training trial rats received footshock (0.3 mA, 3s) they entered preferred dark compartment. exposure to IMO+C lasting 1 h terminated 4 or application immediately 3 this aversive stimulus. Retention tests were performed 2 days trial. In an attempt relate behavioural responses stressor plasma levels hormones we measured ACTH corticosterone under similar conditions as used experiments. terminating resulted very short latencies during retention testing. A impairment test performance found animals exposed training. When stressed exhibited comparably long shown by controls. presented also did not influence learning. estimated IMO+C, both absence presence footshock. Both significantly increased termination, their returned control values within h. Footshock alone corticosterone, however, hormone lower than those blood collection. substantially footshock, but already high corticosterone. conclusion, represents strong stimulus exerting amnesic when shortly Further, findings indicate cold interfere consolidation response. We suggest that moderate circulating may be positively related memory consolidation, while exceedingly have opposite effect.