Huperzine A reverses scopolamine- and muscimol-induced memory deficits in chick

AIM: To study the effects of huperzine A on disruption of spatial memory in duced by scopolamine (a muscarinic antagonist) and muscimol (a GABA(A) agon ist) in passive avoidance task. METHODS: One-trial passive avoidance task w as used to investigate the effects of huperzine A. The avoidance rate was u sed to evaluate memory retention. RESULTS: Both scopolamine (100 ng)and mus cimol (50 ng), injected intracranially 5 min before training, resulted in a decreased avoidance rate. Huperzine A (25 ng), injected intracranially 15 min before training, reversed memory deficits induced by scopolamine and mu scimol at 30 min after training, and this reversal persisted at least 1 h. The improving effects of huperzine A exhibited a bell-shaped dose-response curve. CONCLUSION: Huperzine A improved the process of memory formation not only by acting as a highly potent and selective inhibitor of AChE, but als o by antagonizing effects mediated through the GABA(A) receptor.