Dopamine hypersensitivity in migraine: role of the apomorphine test.

We investigated the effects of apomorphine administration at two different doses (2-10 micrograms/kg, s.c.) in 35 migraineurs in headache-free period and in 20 age-matched healthy control subjects, with and without pretreatment with domperidone. Neither patients or controls complained of headache at either dose, whereas at the dose of 10 micrograms/kg migraineurs showed a statistically significant higher incidence of dopaminergic symptoms (nausea, vomiting, drowsiness, yawning, dizziness, sweating) than controls. Furthermore, symptoms due to postsynaptic dopamine receptors activation (i.e., nausea and vomiting) only appeared in migraineurs. No symptom, however, resembled those characterizing a spontaneous migraine attack. In conclusion, migraineurs show a lower threshold for dopamine receptor activation than normal subjects.