[Arg14,Lys15]Nociceptin is a highly potent and selective NOP receptor (ORL1; OP4) agonist, with an EC50 of 1 nM. [Arg14,Lys15]Nociceptin displays high selectivity over opioid receptors, with IC50s of 0.32, 280, >10000 and 1500 nM for NOP, μ, δ and κ receptors, respectively[1].
[1] Okada K, Sujaku T, Chuman Y, et al. Highly potent nociceptin analog containing the Arg-Lys triple repeat. Biochem Biophys Res Commun. 2000;278(2):493-498. DOI:
10.1006/bbrc.2000.3822[2] Rizzi D, Rizzi A, Bigoni R, et al. [Arg(14),Lys(15)]nociceptin, a highly potent agonist of the nociceptin/orphanin FQ receptor: in vitro and in vivo studies. J Pharmacol Exp Ther. 2002;300(1):57-63. DOI:
10.1124/jpet.300.1.57
