Effects of short-term administration of valproate on serotonin-1A and dopamine receptor function in healthy human subjects.

Objective: To examine the effects of short-term valproate treatment on human brain serotonin and dopamine function by means of challenge tests with ipsapirone, a partial agonist at 5-HT1A receptors, and apomorphine, a dopamine receptor agonist.

Design: Experimental challenge-rechallenge, within-subjects repeated measures, before and at the end of 14 days of treatment with valproate at a dosage of 625 mg/d (reached gradually over the first 5 days).

Participants: Eight healthy male volunteers (mean age 38 years) selected for good physical and mental health who were nonsmokers.