title: MEN16132, a novel potent and selective nonpeptide antagonist for the human bradykinin B2 receptor. In vitro pharmacology and molecular characterization.
abstract: The pharmacological characterization of the novel nonpeptide antagonist for the B2 receptor, namely MEN16132 (4-(S)-Amino-5-(4-{4-[2,4-dichloro-3-(2,4-dimethyl-8-quinolyloxymethyl)phenylsulfonamido]-tetrahydro-2H-4-pyranylcarbonyl}piperazino)-5-oxopentyl](trimethyl)ammonium chloride hydrochloride) is presented. The affinity of MEN16132 for the bradykinin B2 receptor has been investigated by means of competition studies at [3H]bradykinin binding to membranes prepared from Chinese Hamster Ovary (CHO) cells expressing the human bradykinin B2 receptor (pKi 10.5), human lung fibroblasts (pKi 10.5), guinea pig airways (pKi 10.0), guinea pig ileum longitudinal smooth muscle (pKi 10.2), or guinea pig cultured colonic myocytes (pKi 10.3). In all assays MEN16132 was as potent as the peptide antagonist Icatibant, and from 3- to 100-fold more potent than the reference nonpeptide antagonists FR173657 or LF16-0687. The selectivity for the bradykinin B2 receptor was checked at the human bradykinin B1 receptor (pKi<5), and at a panel of 26 different receptors and channels. The antagonist potency was measured in functional assays, i.e., in blocking the bradykinin induced inositolphosphates (IP) accumulation at the human (CHO: pKB 10.3) and guinea pig (colonic myocytes: pKB 10.3) B2 receptor, or in antagonizing the bradykinin induced contractile responses in human (detrusor smooth muscle: pKB 9.9) and guinea pig (ileum longitudinal smooth muscle: pKB 10.1) tissues. In both functional assay types MEN16132 exerted a different antagonist pattern, i.e., surmountable at the human and insurmountable at the guinea pig bradykinin B2 receptors. Moreover, the receptor determinants important for the high affinity interaction of MEN16132 with the human bradykinin B2 receptor were investigated by means of radioligand binding studies performed at 24 point-mutated receptors. The results obtained revealed that residues in transmembrane segment 2 (W86A), 3 (I110A), 6 (W256A), and 7 (Y295A, Y295F but not much Y295W), were crucial for the high affinity of MEN16132. In conclusion, MEN16132 is a new, potent, and selective nonpeptide bradykinin B2 receptor antagonist.
authors.affiliation: Department of Pharmacology, Menarini Ricerche, S.p.A., via Rismondo 12A, Florence, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Cucchi
authors.forename: Stefania
authors.initials: S
authors.lastname: Meini
authors.forename: Alessandro
authors.initials: A
authors.lastname: Bressan
authors.forename: Claudio
authors.initials: C
authors.lastname: Catalani
authors.forename: Francesca
authors.initials: F
authors.lastname: Bellucci
authors.forename: Paolo
authors.initials: P
authors.lastname: Santicioli
authors.forename: Alessandro
authors.initials: A
authors.lastname: Lecci
authors.forename: Angela
authors.initials: A
authors.lastname: Faiella
authors.forename: Luigi
authors.initials: L
authors.lastname: Rotondaro
authors.forename: Sandro
authors.initials: S
authors.lastname: Giuliani
authors.forename: Alessandro
authors.initials: A
authors.lastname: Giolitti
authors.forename: Laura
authors.initials: L
authors.lastname: Quartara
authors.forename: Carlo Alberto
authors.initials: CA
authors.lastname: Maggi
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D001920:Bradykinin / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D065094:Bradykinin B2 Receptor Antagonists; D016466:CHO Cells; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D004305:Dose-Response Relationship, Drug; D006168:Guinea Pigs; D006801:Humans; D066298:In Vitro Techniques; D007295:Inositol Phosphates / Q000378:metabolism; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism; D009952:Ornithine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D017354:Point Mutation; D011804:Quinolines / Q000494:pharmacology; D043782:Receptor, Bradykinin B2 / Q000235:genetics / Q000378:metabolism; D013449:Sulfonamides / Q000378:metabolism / Q000494:pharmacology*; D014162:Transfection
chemical_list: C506838:(4-amino-5-(4-(4-(2,4-dichloro-3-(2,4-dimethyl-8-quinolyloxymethyl)phenylsulfonamido)tetrahydro-2H-4-pyranoylcarbonyl)piperazino)-5-oxopentyl)(trimethyl)ammonium; D065094:Bradykinin B2 Receptor Antagonists; C105311:FR 173657; D007295:Inositol Phosphates; D011804:Quinolines; D043782:Receptor, Bradykinin B2; D013449:Sulfonamides; C065679:icatibant; D009952:Ornithine; D001920:Bradykinin