Effects of valproate on the dopaminergic system in mice.

Valproate is a widely used antiepileptic drug with a known tremor-inducing effect. In this study, we tested the behavioral changes induced by valproate and its effect on the dopaminergic cells in the substantia nigra of mice. This treatment led to a spontaneous locomotor activity, while the explorative behavior was unaltered. The number of dopaminergic cells in the substantia nigra was reduced after valproate treatment. These data are indicative of dopaminergic toxicity, but further studies are needed to demonstrate the exact mechanism.