Influence of antidepressant drugs on learning and memory paradigms in mice.

Effect of antidepressant drugs (amitriptyline, imipramine and fluoxetine) on cognitive functions, impaired by the muscarinic antagonist scopolamine were investigated in mice. The changes in learning and memory tasks were studied using transfer latency on elevated plus maze and employing number of descents in passive avoidance paradigms. Amitriptyline and imipramine showed significant memory impairment. They also potentiated scopolamine-induced memory deficit in a significant way. Amitriptyline and imipramine impair cognitive function possibly due to their anticholinergic properties. Fluoxetine, a newer antidepressant, however showed no effect on learning and memory. It significantly reversed the scopolamine-induced memory impairment in both the tests. Fluoxetine with no anticholinergic property may prove to be a better drug in endogenous depression in elderly patients.