Pharmacological and biochemical effects of Ginkgo biloba extract on learning, memory consolidation and motor activity in old rats.

Effect of administration of the standardized extract of Ginkgo biloba leaves (EGb 761) on learning, memory and exploratory behavior was estimated in water maze and hole-board tests. Rats (18-month old) received for three months EGb 761 at doses: 50, 100 and 150 mg/kg b.w. per day. After completion of the behavioral experiment, concentrations of neurotransmitters were estimated in selected brain regions. ANOVA demonstrated significant differences in the content of monoamines and metabolites between the treatment groups compared to the control. The increased level of 5-hydroxytryptamine (5-HT) in the hippocampus and 5-HIAA (5-HT metabolite) in the prefrontal cortex correlated positively with the retention of spatial memory. Positive correlation between platform crossings in SE during the probe trial and neurotransmitter turnover suggest improvement of spatial memory. Long-term administration of Ginkgo biloba extract can improve spatial memory and motivation with significant changes in the content and metabolism of monoamines in several brain regions.