[Antagonism of piracetam on the amnestic effect of diazepam in mice].

In step-down test, diazepam (1 mg.kg-1 po, 1 h before training) was shown to significantly impair memory acquisition in mice. But piracetam (200 mg.kg-1 ip, 1 h before training) was found to improve the diazepam-induced impairments of learning. By photocell cage method, piracetam showed no significant inhibitory effect on the diazepam-induced spontaneous motor activity in mice. In Y-maze test, Glutamic acid (0.1 microgram, icv, 3 min before training) significantly improved learning in normal mice and the amnesic effect of GABA and diazepam were completely antagonized by Glutamic acid and piracetam (200 mg.kg-1 ip, 1 h before training). These results suggest that increasing GABA-ergic neuronal transmission is unfavorable to learning and memory, but increasing Glu-ergic transmission is contrary to the former. It seemed that the presence of Glu/GABA system in the brain could regulate learning and memory.