In vitro and in vivo pharmacological characterization of J-113397, a potent and selective non-peptidyl ORL1 receptor antagonist.
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.
Banyu Tsukuba Research Institute, Banyu Pharmaceutical Co., Ltd., 3 Okubo, Tsukuba, 300-2611, Ibaraki, Japan. ozakiss@banyu.co.jp
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S
Ozaki
H
H
Kawamoto
Y
Y
Itoh
M
M
Miyaji
T
T
Azuma
D
D
Ichikawa
H
H
Nambu
T
T
Iguchi
Y
Y
Iwasawa
H
H
Ohta
D000701:Analgesics, Opioid / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D001345:Autoradiography; D001562:Benzimidazoles / Q000378:metabolism / Q000494:pharmacology*; D001667:Binding, Competitive / Q000187:drug effects; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D016466:CHO Cells; D003001:Cloning, Molecular; D006224:Cricetinae; D000242:Cyclic AMP / Q000378:metabolism; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D006801:Humans; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009292:Narcotic Antagonists; D018847:Opioid Peptides / Q000378:metabolism; D010147:Pain Measurement / Q000187:drug effects; D010880:Piperidines / Q000378:metabolism / Q000494:pharmacology*; D011957:Receptors, Opioid; D000094942:Nociceptin Receptor
D000701:Analgesics, Opioid; D001562:Benzimidazoles; C402921:J 113397; D009292:Narcotic Antagonists; D018847:Opioid Peptides; D010880:Piperidines; D011957:Receptors, Opioid; C106528:nociceptin, Tyr(1)-; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D000242:Cyclic AMP; D000094942:Nociceptin Receptor