It is well known that initial consolidation requires de novo gene transcription and protein synthesis in order for memory to become stable.The consolidated memory again becomes labile and temporarily sensitive to disruption when retrieved,requiring a reconsolidation process to become permanent.Although it is well established that glucocorticoid receptor (GR) in the basolateral nucleus of amygdala (BLA) is required for consolidation of fear memory,little is known about its role in reconsolidation of fear memory.In the present study,we first examined the effect of GR blockade on post-conditioning consolidation of auditory fear memory (AFM).Intra-BLA infusion of the GR antagonist RU486 0 h post-conditioning impaired long-term AFM,leaving short-term AFM intact.RU486 had no effect if infusion was performed 6 h post-conditioning.We then investigated the effect of the RU486 treatment on post-retrieval reconsolidation of AFM.