Nociceptin(1-13)NH2

[Nphe1]Nociceptin(1-13)NH2, a novel nociceptin/orphanin FQ (NC) endogenous ligand, is a selective and competitive ociceptin receptor antagonist without any residual agonist activity. [Nphe1]nociceptin(1-13)NH2 binds selectively to recombinant nociceptin receptors (pKi=8.4) and antagonizes the inhibitory effects of nociceptin on cyclic AMP accumulation in CHO cells (pA2=6.0). [Nphe1]Nociceptin(1-13)NH2 has the potential to act as an analgesic agent.