title: Irreversible binding kinetics of neuropeptide Y ligands to Y2 but not to Y1 and Y5 receptors.
abstract: Neuropeptide Y (NPY) receptors type 1 (Y1), type 2 Y2) and type 5 (Y5) were tested for their kinetic properties to bind radiolabeled NPY or PYY. Rapid association and dissociation was observed with recombinant (HEK293 cells) and endogenous (SK-N-MC cells) human Y1 and recombinant mouse Y5 receptors. Recombinant (HEK293) and endogenous (SMS-KAN) human Y2 receptors bound both radiolabels comparable to the Y1 receptors, but only minimal ( approximately 20%) dissociation of both radiolabels was observed after long incubation time (>8 h). Furthermore, neither peptide nor small molecule Y2 ligands efficiently competed for binding to Y2 receptors once association binding had been initiated. The Y2-selective antagonist BIIE0246 behaved as an insurmountable antagonist in functional assays when pre-incubated for 30 min before agonist addition, but was a competitive antagonist when co-applied with the agonist. These data show that Y2 receptors in contrast to Y1 and Y5 receptors bind their ligands in an irreversible manner.
authors.affiliation: F. Hoffmann-La Roche AG, Preclinical Research, Basel, Switzerland. fdautzen@prdbe.jnj.com
authors.forename: Frank M
authors.initials: FM
authors.lastname: Dautzenberg
authors.forename: Shiva
authors.initials: S
authors.lastname: Neysari
mesh_terms: D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001552:Benzazepines / Q000494:pharmacology; D001667:Binding, Competitive; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007700:Kinetics; D008024:Ligands; D051379:Mice; D009478:Neuropeptide Y / Q000378:metabolism*; D019894:Peptide YY / Q000378:metabolism*; D017476:Receptors, Neuropeptide Y / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
chemical_list: D001552:Benzazepines; D008024:Ligands; D009478:Neuropeptide Y; D017476:Receptors, Neuropeptide Y; C097212:neuropeptide Y-Y1 receptor; C095889:neuropeptide Y2 receptor; C100568:neuropeptide Y5 receptor; D019894:Peptide YY; D001120:Arginine; C403256:BIIE 0246