[Antagonism of Zn2+ on nootropic action of piracetam in mice].

In mouse step-down test, the memory impairments of acquisition, consolidation and recognition were induced by anisodine, chloramphenical and ethanol, respectively. Piracetam 100 mg/(kg.d) ip for 5 d improved the anisodine-induced impairment of learning. ZnSO4 5 mg/(kg.d) po for 5 d did not improve the 3 impairments. Memory impairments were enhanced by a combined administration of ZnSO4 and piracetam in these 3 models. These results were confirmed by Y-maze method in normal mice.