The trigeminovascular system and migraine: Studies characterizing cerebrovascular and neuropeptide changes seen in humans and cats

Migraine is closely linked to the trigeminal innervation of cranial vessels. This study explored how the trigeminovascular system interacts with effective migraine medications. Researchers conducted experiments on cats and humans. Cats were anesthetized for physiological monitoring and blood sampling. Continuous monitoring of cerebral blood flow used laser Doppler flowmetry. They assessed trigeminal ganglion stimulation's effects on cerebral blood flow. Stimulation increased blood flow by a maximum of 43% at 20 per second. The response was significantly reduced, about 50%, after taking sumatriptan or dihydroergotamine. At a lower stimulation frequency of 5 per second, calcitonin gene-related peptide (CGRP) levels rose significantly. In humans, subcutaneous sumatriptan normalized elevated CGRP levels in 7 of 8 patients. Headache relief was also documented alongside CGRP level normalization. This research helps clarify migraine's physiological mechanisms and medication effects on symptoms. Clinical relevance: Understanding CGRP's role in migraine can guide better treatment strategies.