title: SR147778 [5-(4-bromophenyl)-1-(2,4-dichlorophenyl)-4-ethyl-N-(1-piperidinyl)-1H-pyrazole-3-carboxamide], a new potent and selective antagonist of the CB1 cannabinoid receptor: biochemical and pharmacological characterization.
abstract: Based on binding, functional, and pharmacological data, this study introduces SR147778 [5-(4-bromophenyl)-1-(2,4-dichloro-phenyl)-4-ethyl-N-(1-piperidinyl)-1H-pyrazole-3-carboxamide] as a highly potent, selective, and orally active antagonist for the CB1 receptor. This compound displays nanomolar affinity (Ki = 0.56 and 3.5 nM) for both the rat brain and human CB1 recombinant receptors, respectively. It has low affinity (Ki = 400 nM) for both the rat spleen and human CB2 receptors. Furthermore, it shows no affinity for any of the over 100 targets investigated (IC50 > 1 microM). In vitro, SR147778 antagonizes the inhibitory effects of CP 55,940 [(1R,3R,4R)-3-[2-hydroxy-4-(1,1-dimethylheptyl)phenyl]-4-(3-hydroxypropyl)cyclohexan-1-ol] on both the mouse vas deferens contractions (pA2 value = 8.1) and on forskolin-stimulated adenylyl cyclase activity in the U373 MG cell lines (pA2 value = 8.2) but not in Chinese hamster ovary (CHO) cells permanently expressing the human peripheral cannabinoid receptor (hCB2). SR147778 is able to block the mitogen-activated protein kinase activity induced by CP 55,940 in the CHO cell line expressing human brain cannabinoid receptor (IC50 = 9.6 nM) but was inactive in cells expressing hCB2. After oral administration, SR147778 displaced the ex vivo [3H]-CP 55,940 binding to mouse brain membranes (ED50 = 3.8 mg/kg) with a long duration of action, whereas it did not interact with the CB2 receptor expressed in the mouse spleen. Using different routes of administration, SR147778 (0.3-3 mg/kg) is shown to antagonize pharmacological effects (hypothermia, analgesia, and gastrointestinal transit) induced by R-(+)-(2,3-dihydro-5-methyl-3-[[4-morpholinyl]methyl] pyrol [1,2,3-de]-1,4-benzoxazin-6-yl)(1-naphthalenyl) methanone in mice. Finally, per se, SR147778 (0.3-10 mg/kg) is able to reduce ethanol or sucrose consumption in mice and rats and food intake in fasted and nondeprived rats.
authors.affiliation: Sanofi-Synthelabo Recherche, 371 Rue du Professeur J Blayac, 34184 Montpellier cedex, France. murielle.rinaldi-carmona@sanofi-synthelabo.com
authors.forename: Murielle
authors.initials: M
authors.lastname: Rinaldi-Carmona
authors.forename: Francis
authors.initials: F
authors.lastname: Barth
authors.forename: Christian
authors.initials: C
authors.lastname: Congy
authors.forename: Serge
authors.initials: S
authors.lastname: Martinez
authors.forename: Didier
authors.initials: D
authors.lastname: Oustric
authors.forename: Alain
authors.initials: A
authors.lastname: Pério
authors.forename: Martine
authors.initials: M
authors.lastname: Poncelet
authors.forename: Jeanne
authors.initials: J
authors.lastname: Maruani
authors.forename: Michèle
authors.initials: M
authors.lastname: Arnone
authors.forename: Olivier
authors.initials: O
authors.lastname: Finance
authors.forename: Philippe
authors.initials: P
authors.lastname: Soubrié
authors.forename: Gérard
authors.initials: G
authors.lastname: Le Fur
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D016466:CHO Cells; D006224:Cricetinae; D008297:Male; D051379:Mice; D010880:Piperidines / Q000494:pharmacology*; D011720:Pyrazoles / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D043884:Receptor, Cannabinoid, CB1 / Q000037:antagonists & inhibitors*; D013045:Species Specificity
chemical_list: D010880:Piperidines; D011720:Pyrazoles; D043884:Receptor, Cannabinoid, CB1; C492668:surinabant