[Physiopathology of migraine]

In those subjects genetically susceptible to migraine, biological rhythms or excessive afferent stimulation trigger an episodic neurovascular reaction with focal neurological symptoms, headache and nausea as its most common manifestations. Mood changes and a craving for sweet foods point to a preliminary hypothalamic disturbance. The referral of ice-cream headache and ice-pick pains to the habitual site of migraine headache (even in the intervals between attacks) indicate defective control of trigeminal pathways. Laboratory experiments have demonstrated that projections from the brainstem, releasing monoamines and peptides as transmitter agents, can mimic the vascular changes of migraine. Serotonin released from platelets may sensitize vessels to respond to distension by generating pain-producing afferent discharges. Central depletion of monoamines can accentuate the perception of pain by reducing the efficacy of the endogenous pain control system. The intravenous injection of serotonin relieves migraine headache but produces side-effects. A new drug, sumatriptan, acting on a subtype of serotonin receptors, the 5HT1-like receptor, is undergoing clinical trial for the relief of acute attacks of migraine. Antagonist of the 5HT2 receptor are beneficial in interval therapy for the prevention of migraine. Increased knowledge of physiological mechanisms and neurotransmitters that can mediate the various components of the migraine attack opens the way for improvements in pharmacotherapy.