A dose-response study of intravenous m-chlorophenylpiperazine in normal subjects

A placebo-controlled dose-response study of the direct serotonin receptor agonist m-chlorophenylpiperazine (MCPP), intravenously infused over 90 s in 0.06 and 0.08 mg/kg doses, was conducted in nine normal male subjects. Cortisol, prolactin, MCPP serum levels and behavioral responses were measured over a 210-min period. Both doses caused significant cortisol and prolactin release and were associated with significantly greater behavioral effects as compared to placebo. Though the two doses were associated with different MCPP serum levels, they did not significantly differ in their hormonal and behavioral effects.