The elevated T maze, a new experimental model of anxiety and memory: effect of diazepam.

In rats placed in a T maze consisting of an enclosed arm at right angles with two open arms elevated 50 cm above the ground, ip doses of 2 and 4 mg/kg diazepam (DZP) abolished the delay of withdrawal from the enclosed arm towards the open arms, measured by retesting in the presence of the drug soon after training, as well as by further retesting 72 h later, in the absence of the drug. Therefore, DZP had both anxiolytic and amnestic effects on this inhibitory avoidance task. In contrast, DZP did not affect the latency of withdrawal from one of the open arms towards the closed arm on the first day. Moreover, the latency of this escape response similarly decreased in all treatment groups in the retest performed 72 h later, indicating that memory of this task was resistant to DZP. These results support the view that the anxiolytic and amnestic effects of benzodiazepines are closely related, and suggest that this new elevated T maze model may be useful for simultaneous measurement of drug effects on anxiety and memory.