Relationship between Dopamine and Serotonin on the Effect of Ginkgo biloba Extract in the Treatment of Obsessive-compulsive Disorder in Rodents

In this study, the effect of EGb-761, the standardized extract of Ginkgo biloba at dose levels of 50, 100 and 200 mg/kg was investigated on experimental models of obsessive-compulsive disorder such as quinpiroleinduced compulsive checking in rats and marble burying behaviour in mice. Water maze test was used to evaluate the effect on spatial memory and the underlying mechanisms were predicted based on rat brain dopamine and serotonin levels. EGb-761 at 100 and 200 mg/kg showed signifi cant improvement against quinpirole-induced compulsions. A protective effect on memory task was observed in EGb-761-treated rats. This could be attributed to the increase in serotonin and decrease in the dopamine levels. The protective effect of EGb-761 in the treatment of obsessive-compulsive disorder is apparent through the performance in the open fi eld and marble burying behaviour.