BAN ORL 24 is an antagonist of the nociceptin (NOP) receptor (K_i= 0.24 nM in a radioligand binding assay using CHO cell membranes expressing the human receptor).¹It is selective for NOP receptors over μ-, δ-, and κ-opioid receptors (K_is = 0.19, 0.34, and >1 µM, respectively). BAN ORL 24 reduces NOP-induced GTPγS binding (pA₂= 9.98) and calcium mobilization (K_B= 0.93 nM) in CHO cells. It inhibits electrically induced twitches in isolated mouse and rat vas deferens, as well as isolated guinea pig ileum, when used at a concentration of 100 nM. BAN ORL 24 (10 mg/kg) reverses thermal and mechanical antinociceptive activities induced by the dual agonist of µ-opioid and NOP receptors BPR1M97 in mice.²

1.Fischetti, C., Camarda, V., Rizzi, A., et al.Pharmacological characterization of the nociceptin/orphanin FQ receptor non peptide antagonist Compound 24Eur. J. Pharmacol.614(1-3)50-57(2009) 2.Chao, P.-K., Chang, H.-F., Chang, W.-T., et al.BPR1M97, a dual mu opioid receptor/nociceptin-orphanin FQ peptide receptor agonist, produces potent antinociceptive effects with safer properties than morphineNeuropharmacology166107678(2020)