Effect of valproic acid on 5-hydroxytryptamine turnover in mouse brain

The effect of the antiepileptic drug valproic acid (di-n-propylacetic acid, 200 mg kg-1) on brain 5-hydroxytryptamine (5-HT) synthesis during monoamine oxidase inhibition by pargyline hydrochloride (120 mg kg-1) was studied in mice. Valproic acid increased 5-HT synthesis and elevated 5-hydroxyindoleacetic acid level in brain indicating that turnover of 5-HT is increased. The possible significance of this effect in relation to anticonvulsant action of valproic acid is discussed.