Triptans are a class of medications used in the treatment of migraine headaches. Triptans act as antimigraine agents by selectively binding to the serotonin receptors 5-HT1B and 5-HT1D. Triptan binding to the vascular 5-HT1B receptors leads to vasoconstriction of the cranial arteries, which painfully dilate during a migraine attack. Sumatriptan is a 5-HT1B/1D receptor agonist and leads to vasoconstriction in the basilar artery and the blood vessels of the dura mater. It decreases peripheral nociception either by selective cranial vasoconstriction or an effect on trigeminovascular nerves. The blocking effect of sumatriptan indicated a peripheral effect on trigeminal vascular nerves in neurogenically mediated plasma extravasation. Sumatriptan inhibits the presynaptic terminal of the trigeminal nucleus caudalis, which leads to the reversal of facial allodynia. Triptans decrease transmission of the pain impulses to the trigeminal nucleus caudalis and reduce inflammatory mediators from trigeminal nerves, therefore reducing calcitonin gene-related peptide-mediated vasodilation. Migraine pain is associated with middle cerebral artery dilatation, which leads to a lower velocity of regional cerebral blood flow. Sumatriptan reverses the dilatation of MCA, which suggests that the 5-HT receptor system has a role in the pathogenesis of a migraine.

Sumatriptan Mechanism of Action pathway References