Fig. 4.  Glibenclamide (Glib), but not iberiotoxin (Iberi), blocks the dilation effects of cromakalim and calcitonin gene–related polypeptide (CGRP). Iberiotoxin, but not glibenclamide, blocks the dilation effects of NS1619 (n = 5). (A ) Effects of 10 nM cromakalim, CGRP, and NS1619, in the presence versus  absence of pretreatment agents. (B ) Effects of 1 μM cromakalim, CGRP, and NS1619. * First-administered agent.