Interaction between midazolam-induced anterograde amnesia and memory enhancement by treatments given immediately after training on an inhibitory avoidance task in rats

The aim of this study was to evaluate the effects of interactions between memory modulatory systems on inhibitory avoidance retention in rats. Adult female Wistar rats were trained and tested in a step-down inhibitory avoidance task (0.3 mA footshock). The training-test interval was 24 h. The animals received an intraperitoneal injection of saline or midazolam (1 mg/kg) 15 min before training, and saline, adrenaline (25 mug/kg), naloxone (0.4 mg/kg), dexamethasone (0.3 mg/kg) or glucose (320 mg/kg) immediately after training. In saline-pretreated rats, adrenaline, naloxone, dexamethasone and glucose enhanced memory retention. Pretreatment with midazolam prevented the facilitatory effects of those treatments. These findings suggest that the facilitation of learning by post-training memory-enhancing treatments is prevented by midazolam. (C) 2002 Lippincott Williams Wilkins.