Basolateral amygdala lesions block diazepam-induced anterograde amnesia in an inhibitory avoidance task.

This experiment examined the effects of diazepam (DZP) on acquisition and retention of an inhibitory avoidance response by rats with excitotoxic-induced lesions of central (CE), lateral (LAT), or basolateral (BL) amygdala nuclei. Sham-operated and lesioned rats received i.p. injections of DZP (2.0 mg per kg of body weight) 30 min before training in a continuous multiple-trial inhibitory avoidance task. Retention was tested 48 h later. Acquisition was not impaired by the lesions or the DZP. Retention was impaired in animals with CE and LAT lesions in comparison with sham-operated controls. DZP impaired retention in the sham-operated controls as well as CE- and LAT-lesioned animals but did not affect retention in animals with BL lesions. These findings indicate that the DZP-induced anterograde amnesia for inhibitory avoidance training is mediated through influences involving the BL amygdala nucleus.