Induction of migrainelike headaches by the serotonin agonist m-chlorophenylpiperazine

In a study of serotonin (5-HT) function in patients with eating disorders and healthy control subjects, severe headaches with features of common migraine occurred unexpectedly in 28 of 52 subjects (54%) 8 to 12 hours after receiving a single oral dose of the 5-HT receptor agonist m-chlorophenylpiperazine (m-CPP), 0.5 mg/kg. None of the same subjects developed similar late-occurring headaches after placebo or the 5-HT precursor, L-tryptophan, 100 mg/kg given intravenously. The frequency of these migrainelike headaches was not significantly different between patients with bulimia or anorexia nervosa and control subjects, but incidence of headaches was significantly greater in subjects with a personal or family history of migraine, with almost all predisposed individuals (18 of 20, 90%) developing severe symptoms. Headache ratings were also significantly correlated (rho = 0.70; p less than 0.0001) with peak concentrations of m-CPP in plasma. These observations indicate that m-CPP may provide a novel probe for studies of the pathophysiology of migraine headaches.