KCNQ4 and migraine disorder: On the other hand, the rather selective Kv7.4/Kv7.5 activator (S)-1 [29], an orally bioavailable acrylamide derivative showing activity in a rat cortical spreading depression model of human migraine [46] and which binds to the same pore pocket used by pan-Kv7 activators [29], dose-dependently counteracted BK-induced [Ca2+]i rises, showing a maximal efficacy identical to that of RTG and ICA-27243 (~60% maximal blockade), but an IC50 of about 7 μM, thus showing a potency identical to that shown by this drug for the activation of Kv7.4-mediated currents [29].