title: Characterization of V0162, a new long-acting antagonist at human M3 muscarinic acetylcholine receptors.
abstract: The anticholinergic properties of the mequitazine enantiomer V0162 make it a drug candidate for the treatment of chronic obstructive airway diseases. Here, we compared V0162's in vitro pharmacological activity at recombinant human M3 muscarinic acetylcholine receptors (hM3Rs) with that of other anticholinergics, using (i) a radioligand binding assay, (ii) a functional reporter gene assay and (iii) a bronchoconstriction inhibition assay on human bronchial preparations. V0162 had high affinity for hM3Rs, with a pKi varying from 9.01 after a 2 h incubation to 9.21 after 23 h. The other mequitazine enantiomer (V0114) was less potent. V0162 displayed rapid off-kinetics and a biphasic time course of binding. V0162 was found to be an antagonist behaving as an inverse agonist for hM3R-mediated reporter gene activation, with much the same efficacy as atropine, ipratropium and tiotropium. However, in contrast to ipratropium and atropine, V0162's inhibitory potency was only slightly affected by compound washout. V0162 antagonized acetylcholine-mediated contractions in a human bronchial preparation; the pA2 values increased with the incubation time (up to 2 h). Moreover, there was a progressive increase in V0162's ability to inhibit electrically-induced contractions, which persisted after compound washout. In conclusion, V0162 is the most active mequitazine enantiomer at hM3Rs and shows a complex pattern of binding to the membrane compartment. These particular features may be of therapeutic value when persistent antagonism at hM3Rs is required.
authors.affiliation: Department of Cellular and Molecular Biology, Centre de Recherche Pierre Fabre, 17 Avenue Jean Moulin, F-81106 Castres Cedex, France. Electronic address: peter.heusler@pierre-fabre.com.
authors.forename: Peter
authors.initials: P
authors.lastname: Heusler
authors.affiliation: Department of Cellular and Molecular Biology, Centre de Recherche Pierre Fabre, 17 Avenue Jean Moulin, F-81106 Castres Cedex, France. Electronic address: didier.cussac@pierre-fabre.com.
authors.forename: Didier
authors.initials: D
authors.lastname: Cussac
authors.affiliation: Respiratory Pharmacology Research Laboratory, UPRES EA220, Hôpital Foch, Université de Versailles Saint-Quentin, 11 rue Guillaume Lenoir, F-92150 Suresnes, France. Electronic address: upresea220@orange.fr.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Naline
authors.affiliation: Department of Cellular and Molecular Biology, Centre de Recherche Pierre Fabre, 17 Avenue Jean Moulin, F-81106 Castres Cedex, France. Electronic address: stephanie.tardif@pierre-fabre.com.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Tardif
authors.affiliation: Centre de Recherche & Développement Pierre Fabre, 3 Avenue Hubert Curien BP13562, F-31035 Toulouse, France. Electronic address: thierry.clerc@pierre-fabre.com.
authors.forename: Thierry
authors.initials: T
authors.lastname: Clerc
authors.affiliation: Respiratory Pharmacology Research Laboratory, UPRES EA220, Hôpital Foch, Université de Versailles Saint-Quentin, 11 rue Guillaume Lenoir, F-92150 Suresnes, France. Electronic address: p.devillier@hopital-foch.org.
authors.forename: Philippe
authors.initials: P
authors.lastname: Devillier
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000368:Aged; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001980:Bronchi / Q000187:drug effects / Q000378:metabolism; D016084:Bronchoconstriction / Q000187:drug effects; D001993:Bronchodilator Agents / Q000494:pharmacology; D016466:CHO Cells; D003412:Cricetulus; D005260:Female; D017930:Genes, Reporter / Q000187:drug effects; D006801:Humans; D009241:Ipratropium / Q000494:pharmacology; D008297:Male; D018727:Muscarinic Antagonists / Q000494:pharmacology*; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy / Q000378:metabolism; D043587:Receptor, Muscarinic M3 / Q000037:antagonists & inhibitors*; D000069447:Tiotropium Bromide / Q000494:pharmacology
chemical_list: D001993:Bronchodilator Agents; D018727:Muscarinic Antagonists; D043587:Receptor, Muscarinic M3; D001285:Atropine; D009241:Ipratropium; D000109:Acetylcholine; D000069447:Tiotropium Bromide
keywords: COPD; Human M(3) muscarinic receptor; Human bronchus; Long-acting anticholinergic; Tiotropium; V0162