Maryam Nazari - Research Center and Department of Physiology, Semnan University Medical Sciences, Semnan, Iran
Abbas Ali Vafaei - Research Center and Department of Physiology, Semnan University Medical Sciences, Semnan, Iran
Ali Rashidy Pour - Research Center and Department of Physiology, Semnan University Medical Sciences, Semnan, Iran

Introduction: Reactivation of a stabilized memory induces a late phase of memory reconsolidation process which is now called as late reconsolidation. This phase is critical for the persistence of long term memory. Recent studies in our and other laboratories suggest that glucocorticoid receptors are involved in persistence of fear memory. The aim of the present study was to determine the effect of systemic injection of corticosterone as an endogenous ligand of glucocorticoids on persistence of fear memory reconsolidation in rats. Materials and methods: In this experimental study male Wistar rats (250-270 g) were trained in an inhibitory avoidance task (1mA, 3S). Animals received systemic injection of vehicle or corticosterone (1, 3 and 10 mg/kg IP) immediately and 12h after memory reactivation Retention tests were done 2 and 7 days after memory reactivation. Results: Results indicated that administration of corticosterone 10mg/kg, 12h after memory reactivation significantly impaired the memory persistence. Conclusion: These findings show that systemic injection of corticosterone in a restricted time window after fear memory retrieval has an important role on late reconsolidation of fear memory

Glucocorticoids, Corticosterone, Late reconsolidation, Fear memory, Passive avoidance task