Effects of red ginseng saponins and nootropic drugs on impaired acquisition of ethanol-treated rats in passive avoidance performance

Effects of single and repeated administration of red ginseng total saponins (ROTS) and nootropic drugs were examined on impairment of acquisition induced by single oral administration of 3 g/kg ethanol (EtOH) in a step through test. The inhibitory effect of EtOH on acquisition was significantly reduced following single or repeated RGTS administration. The nootropic drugs, piracetam and N-methyl-D-glucamine, given orally significantly reduced impairment of acquisition induced by EtOH. On the other hand, the inhibitory effect of repeated RGTS on the EtOH-induced amnesia was blocked by the pretreatment of alpha-methyl-p-tyrosine (alpha-MT), an inhibitor of catecholamine synthesis, in a dose-dependent manner but not p-chlorophenylalanine (PCPA), an inhibitor of serotonin synthesis, whereas the inhibitory effect of repeated N-methyl-D-glucamine on the EtOH-induced amnesia was blocked neither by alpha-MT nor PCPA. These results suggest that repeated RGTS and N-methyl-D-glucamine ameliorate the impairing effect of EtOH on acquisition, and the effect of RGTS on EtOH-induced amnesia is dependent on the catecholaminergic but not serotonergic neuronal activity, while RGTS and N-methyl-D-glucamine seem to have a different mechanism on EtOH-induced amnesia.