title: Characterization of muscarinic receptor subtypes in human tissues.
abstract: The affinities of selective, pirenzepine and AF-DX 116, and classical, N-methylscopolamine and atropine, muscarinic cholinergic receptor antagonists were investigated in displacement binding experiments with [3H]Pirenzepine and [3H]N-methylscopolamine in membranes from human autoptic tissues (forebrain, cerebellum, atria, ventricle and submaxillary salivary glands). Affinity estimates of N-methylscopolamine and atropine indicated a non-selective profile. Pirenzepine showed differentiation between the M1 neuronal receptor of the forebrain and the receptors in other tissues while AF-DX 116 clearly discriminated between muscarinic receptors of heart and glands. The results in human tissues confirm the previously described selectivity profiles of pirenzepine and AF-DX 116 in rat tissues. These findings thus reveal the presence also in man of three distinct muscarinic receptor subtypes: the neuronal M1, the cardiac M2 and the glandular M3.
authors.affiliation: Department of Biochemistry, Istituto De Angeli S.p.A., Milan, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Giraldo
authors.forename: F
authors.initials: F
authors.lastname: Martos
authors.forename: A
authors.initials: A
authors.lastname: Gomez
authors.forename: A
authors.initials: A
authors.lastname: Garcia
authors.forename: M A
authors.initials: MA
authors.lastname: Vigano
authors.forename: H
authors.initials: H
authors.lastname: Ladinsky
authors.forename: F
authors.initials: F
authors.lastname: Sanchez de La Cuesta
mesh_terms: D001921:Brain / Q000378:metabolism*; D002531:Cerebellum / Q000378:metabolism; D006325:Heart Atria / Q000378:metabolism; D006352:Heart Ventricles / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D009206:Myocardium / Q000378:metabolism*; D019832:N-Methylscopolamine; D009928:Organ Specificity; D010890:Pirenzepine / Q000378:metabolism*; D011976:Receptors, Muscarinic / Q000378:metabolism*; D012602:Scopolamine Derivatives / Q000378:metabolism*; D013363:Submandibular Gland / Q000378:metabolism*
chemical_list: D011976:Receptors, Muscarinic; D012602:Scopolamine Derivatives; D010890:Pirenzepine; D019832:N-Methylscopolamine