Pathogenesis of migraine: role of neuromodulators.

The pathogenesis of migraine is still, today, a hotly debated issue. Recent biochemical studies report the occurrence in migraine of metabolic abnormalities in the synthesis of neurotransmitters and neuromodulators. These include a metabolic shift directing tyrosine metabolism toward the decarboxylation pathway, therein resulting in an unphysiological production of noradrenaline and dopamine along with increased synthesis of traces amines such as tyramine, octopamine, and synephrine. This biochemical alteration is possibly favored by impaired mitochondrial function and high levels of glutamate in the central nervous system (CNS) of migraine patients. The unbalanced levels of the neurotransmitters (dopamine and noradrenaline) and neuromodulators (eg, tyramine, octopamine, and synephrine) in the synaptic dopaminergic and noradrenergic clefts of the pain matrix pathways may activate, downstream, the trigeminal system that releases calcitonin gene-related peptide. This induces the formation of an inflammatory soup, the sensitization of first trigeminal neuron, and the migraine attack. In view of this, we propose that migraine attacks derive from a top-down dysfunctional process that initiates in the frontal lobe in a hyperexcitable and hypoenergetic brain, thereafter progressing downstream resulting in abnormally activated nuclei of the pain matrix.