1. Academic Validation
  2. In vitro and in vivo pharmacological characterization of J-113397, a potent and selective non-peptidyl ORL1 receptor antagonist

In vitro and in vivo pharmacological characterization of J-113397, a potent and selective non-peptidyl ORL1 receptor antagonist

  • Eur J Pharmacol. 2000 Aug 18;402(1-2):45-53. doi: 10.1016/s0014-2999(00)00520-3.
S Ozaki 1 H Kawamoto Y Itoh M Miyaji T Azuma D Ichikawa H Nambu T Iguchi Y Iwasawa H Ohta
Affiliations

Affiliation

  • 1 Banyu Tsukuba Research Institute, Banyu Pharmaceutical Co., Ltd., 3 Okubo, Tsukuba, 300-2611, Ibaraki, Japan. [email protected]
Abstract

1-[(3R,4R)-1-cyclooctylmethyl-3-hydroxymethyl-4-piperidyl]-3-ethyl -1, 3-dihydro-2H-benzimidazol-2-one (J-113397) was found to be the first potent nonpeptidyl ORL1 receptor antagonist (K(i): cloned human ORL1=1.8 nM) with high selectivity over other opioid receptors (K(i): 1000 nM for human mu-opioid receptor, >10,000 nM for human delta-opioid receptor, and 640 nM for human kappa-opioid receptor). In vitro, J-113397 inhibited nociceptin/orphanin FQ-stimulated [35S]guanosine 5'-O-(gamma-thio)triphosphate (GTP gamma S) binding to Chinese Hamster Ovary (CHO) cells expressing ORL1 (CHO-ORL1) with an IC(50) value of 5.3 nM but had no effect on [35S]GTP gamma S binding by itself. Schild plot analysis of the [35S]GTP gamma S binding assay and cAMP assay using CHO-ORL1 indicated competitive antagonism of J-113397 on the ORL1 receptor. In CHO cells expressing mu-, delta- or kappa-opioid receptors, J-113397 had no effects on [35S]GTP gamma S binding up to a concentration of 100 nM, indicating selective antagonism of the compound on the ORL1 receptor. In vivo, J-113397, when administered subcutaneously (s.c.), dose-dependently inhibited hyperalgesia elicited by intracerebroventricular (i.c.v.) administration of nociceptin/orphanin FQ in a tail-flick test with mice. An in vitro binding study using mouse brains indicated that J-113397 possesses high affinity for the mouse ORL1 receptor (K(i): 1.1 nM) as well as the human receptor. In summary, J-113397 is the first potent, selective ORL1 receptor antagonist that may be useful in elucidating the physiological roles of nociceptin/orphanin FQ.

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