A new nonvascular interpretation of syncopal migraine.

Migraine suffers who experience spontaneous syncopes (syncopal migraine) during attacks exhibit a dramatic intolerance to bromocriptine, a dopamine agonist. An oral dose of this drug renders these patients unable to stand, even for some hours, because of precipitously falling of arterial blood pressure. Treatment with domperidone, a specific dopamine receptor antagonist, abolishes the syncopal effect of bromocriptine. This evidence is compatible with a supersensitivity of those dopamine receptors, which exert an inhibiting activity and are located on blood pressure regulating centers as well as on cardiovascular sympathergic neurons.