Highly potent and selective NOP receptor agonist (EC50 = 1 nM). Displays > 875-fold selectivity over opioid receptors (IC50 values are 0.32, 280, > 10000 and 1500 for NOP, μ, δ and κ receptors respectively). Longer lasting and 30-fold more potent than noc
Selective and competitive nociceptin receptor antagonist, devoid of any agonist activity. Binds selectively to recombinant nociceptin receptors (pKi = 8.4), and competitively antagonizes the actions of nociceptin in vitro and in vivo.
Potent agonist of the nociceptin (ORL1) receptor, demonstrated both in vitro and in vivo. Selective, competitive antagonism at the nociceptin receptor has also been reported (pA2 = 7.02 and 6.75 in the guinea pig ileum and mouse vas deferens respectively)
Ac-RYYRWK-NH2 is a highly effective and specific partial agonist for the nociceptin receptor (NOP). It demonstrates a remarkable affinity for rat cortical membranes ORL1, with [3H]Ac-RYYRWK-NH2 exhibiting a Kd value of 0.071 nM. However, it shows negligible affinity towards μ-, κ-, or δ-opioid receptors.
Orphanin FQ(1-11) is a peptide fragment containing amino acids 1-11 of Nociceptin. Orphanin FQ(1-11) is a potent agonist of the ORL1/KOR-3 receptor (Ki = 55 nM) and displays no affinity for opioid receptors, including μ, δ, κ1 and κ3 receptors (Ki >1000 nM). Orphanin FQ(1-11) displays analgesic properties in CD-1 mice.
High affinity ligand for the NOP site (Ki = 1.5 nM). Antagonizes nociceptin-stimulated GTP binding in rat brain and the chronotropic effect of nociceptin on rat cardiomyocytes. However, displays potent agonist properties in vivo, inhibiting locomotor acti