Dopamine involvement in the migraine attack.

Clinical evidence and recent genetic findings seem to indicate an involvement of dopamine in the pathophysiology of the migraine attack. Prodromal symptomatology (mood changes, yawning, drowsiness, food craving), accompanying symptoms (nausea, vomiting, hypotension) and postdromal symptoms (mood changes, drowsiness, tiredness) may be related to dopaminergic activation. The dopaminergic system could also play a role in the headache phase, either by taking part in nociception mechanisms, or by regulating cerebral blood flow. A body of pharmacological findings seems to support this involvement. Migraine patients, between attacks, show a higher responsiveness to acute administration of dopaminergic agents. Apomorphine administration induces in migraineurs more yawns as well other dopaminergic symptoms e.g. nausea, vomiting, dizziness. Migraine has been associated with hypotension and, occasionally, with syncope. Bromocriptine causes severe orthostatic syndrome in migraine patients. Both piribedil and apomorphine markedly increase cerebral blood flow of migraine patients, thus indicating enhanced responsiveness of dopamine receptors which are involved in cerebral blood flow regulation. Interictal dopaminergic hypersensitivity has also been demonstrated by means of neuroendocrine tests. Altered dopaminergic control of prolactin secretion exists in migrainous women. L-deprenyl, a MAO-B inhibitor, is significantly more effective in reducing prolactin levels in migraineurs than in controls. Taken together, these findings support the view that hypersensitivity of peripheral and central dopaminergic receptors is a specific migraine trait. Finally, a high density of lymphocytic D5 receptors has been found in migraine sufferers, thus suggesting their upregulation. Therefore, the hypothesis that dopaminergic activation is a primary pathophysiological component in certain subtypes of migraine, namely those characterised by marked dopaminergic symptomatology, has been advanced. From this perspective, a blockade of dopaminergic hyperresponsive receptors can be considered as a rationale for the therapy of migraine.