A neuropeptide with diverse biological activities; binds selectively to a heteromeric complex of CRLR and RAMP1 (IC50 = 0.01 nM) over a complex of CLCR and RAMP2 (IC50 = 300 nM); binds to rat brain and spleen membrane preparations (IC50s = 1.1 and 1 nM, respectively); relaxes PGF2α-precontracted human cerebral and middle meningeal arterial segments (IC50s = 0.38 and 4.9 nM, respectively); induces a 50% increase in diameter of ET-1-precontracted arterioles in hamster cheek pouch (15.8 pM)