title: Carboxyl residue(s) at the ligand-binding site of rat muscarinic receptors.
abstract: Chemical modification of muscarinic receptors of rat cerebral cortex, brain stem and atria by a carboxyl-group-specific reagent, namely trimethyloxonium ion (TMO+) reduces the number of tritium-labeled antagonist- and agonist-binding sites in a dose-dependent way. No such effect is observed when modification is carried out in the presence of atropine, oxotremorine or carbamylcholine. These findings suggest that TMO+ specifically methylates the carboxyl residue(s) positioned at the binding site in members of the M1 and M2 receptor family.
authors.affiliation: Department of Biochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel.
authors.forename: R
authors.initials: R
authors.lastname: Galron
authors.forename: M
authors.initials: M
authors.lastname: Sokolovsky
mesh_terms: D000345:Affinity Labels; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001665:Binding Sites / Q000187:drug effects; D001933:Brain Stem / Q000032:analysis / Q000187:drug effects; D002217:Carbachol / Q000494:pharmacology; D002540:Cerebral Cortex / Q000032:analysis; D006325:Heart Atria / Q000032:analysis / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D008745:Methylation; D009861:Onium Compounds / Q000494:pharmacology*; D010095:Oxotremorine / Q000494:pharmacology; D051381:Rats; D011976:Receptors, Muscarinic / Q000032:analysis / Q000187:drug effects*
chemical_list: D000345:Affinity Labels; D009861:Onium Compounds; D011976:Receptors, Muscarinic; D010095:Oxotremorine; D001285:Atropine; D002217:Carbachol; C009576:trimethyloxonium