The rationale of this idea was based on studies showing that the KATP channel opener levcromakalim was a potent inducer of migraine in patients (Table 1) [55, 56], and that both CGRP and PACAP elevate cAMP levels, which in vascular smooth muscle would activate the channels, leading to vasodilation associated with headache [71]. The gene discussed is ADCYAP1; the disease is Headache.