The Involvement of ATP Sensitive Potassium Channel in Migraine Aura and Migraine Pain.

Migraine Pain The trigeminovascular system is the anatomical and physiological substrate of migraine pain. Nociceptive transmission originates from activation and sensitization of first-order trigeminovascular neurons. Their cell bodies are in the trigeminal ganglion, and their afferent fibers innervate the meninges and its vessels. Ascending nociceptive transmission from the trigeminal ganglion is projected to the brain stem, activating and sensitizing second-order trigeminovascular neurons, including those in the spinal trigeminal nucleus. This, in turn, activates and sensitizes third-order trigeminovascular neurons in the thalamus, which subsequently relay the nociceptive transmission to the somatosensory cortex and other cortical areas, ultimately resulting in migraine pain. Although the biological underpinnings of migraine pain are incompletely understood, signaling pathways have been identified that are putatively responsible for the genesis of migraine pain. Recent human experimental data have implicated opening of KATP channels in migraine pathogenesis. In two randomized controlled trials, it was demonstrated that intravenous infusion of levcromakalim - an opener of KATP channels - induced migraine pain in people with migraine with and without aura. \- It remains unknown whether KATP channel opening causes migraine pain by activation of meningeal nociceptors and ascending trigeminal nociceptive pathways, as proposed during spontaneous migraine attacks. Migraine Aura About one-third of people with migraine experience aura symptoms, which are characterized by reversible focal neurologic symptoms, typically comprising visual or hemisensory disturbances. The physiological substrate of the aura phase of migraine is thought to be cortical spreading depression (CSD), a self-propagating wave of depolarization across the cerebral cortex that disrupts ionic gradients and is followed by cerebral hypoperfusion. Recently, it was reported that intravenous infusion of levcromakalim - an opener of KATP channels - induced migraine aura in migraine with aura patients. \- It remains unknown whether KATP channel opening causes CSD which leads to migraine aura, as observed during spontaneous migraine attacks.