['To measure plasma and platelet levels of dopamine in patients with migraine with aura, migraine without aura, and cluster headache.', 'Clinical, genetic, and pharmacological evidences suggest that an abnormality of dopaminergic system plays a role in migraine pathogenesis. Direct evidence of an abnormal metabolism of dopamine in migraine, however, is lacking.', 'Plasma and platelet levels of dopamine were measured in patients with migraine with aura or migraine without aura during headache-free periods and in patients with cluster headache during the remission and active periods, as compared with healthy control subjects, using a multichannel electrochemical high-performance liquid chromatography system.', 'Plasma levels of dopamine were not detectable with our methodology. Platelet levels of dopamine were higher in both types of migraine (migraine without aura = .20 +/- .17 ng/10(8) platelets; migraine with aura = .16 +/- .19 ng/10(8) platelets) than in control subjects (.10 +/- .11 ng/10(8) platelets), although in migraine with aura patients the difference was not significant. Patients with cluster headache showed the highest levels of platelet dopamine (.34 +/- .36 ng/10(8) platelets).'] Are platelet levels of dopamine increased in migraine and cluster headache?