A neuropeptide with diverse biological activities; binds selectively to heteromeric complexes of CRLR and RAMP1 or 3 (IC50s = 7 and 23 nM, respectively) over a complex of CLCR and RAMP2 (IC50 = >1,000 nM); binds to rat brain and spleen membrane preparations (IC50s = 3.9 and 3.5 nM, respectively); relaxes prostaglandin F2α-precontracted human cerebral and middle meningeal arterial segments (IC50s = 0.23 and 2.24 nM, respectively); decreases MABP and increases PA and MMA diameters in rats with closed cranial windows (0.01-3,000 ng/kg); induces a 50% increase in diameter of ET-1-precontracted arterioles in vivo in hamster cheek pouch (39.8 pM)