The role of vasodilation in PACAP38-induced migraine attacks seems to be further enforced by the ability of sumatriptan, a well-known anti-migraine drug with vasoconstrictor properties, to prevent PACAP38-induced migraine attacks (induction rate 15% after sumatriptan vs. 42% after placebo) [34]. This evidence concerns the gene ADCYAP1 and migraine disorder.