title: Beta-adrenoceptors and human skeletal muscle characterisation of receptor subtype and effect of age.
abstract: 1. Rectus abdominis muscle biopsies were obtained from 28 patients undergoing abdominal surgery. In membranes prepared from these biopsies beta-adrenoceptor binding was examined. The apparent affinity (KD) and the density (Bmax) of the receptors for the radioligand (-)-[125I]cyanopindolol were 28.5 +/- 2.7 (pM) and 25.9 +/- 2.1 (fmol mg-1 protein) (mean +/- s.e. mean) respectively. In forceps biopsies from vastus lateralis muscle from four healthy volunteers the values for KD and Bmax were 22.5 +/- 4.4 (pM) and 16.4 +/- 2.2 (fmol mg-1 protein). The binding characteristics for the radioligand were similar in the biopsies from the two muscle sites. 2. Inhibition of the radioligand binding by the selective beta 2-adrenoceptor antagonist ICI 118551 (KI = 117 +/- 45 nM) and selective beta 1-adrenoceptor antagonist metoprolol (KI = 15229 +/- 5046 nM) suggests the dominance of beta 2-adrenoceptor subtype in human skeletal muscle. 3. There were no significant differences in the skeletal muscle beta-adrenoceptor densities or affinities between the young and older patients.
authors.affiliation: Department of Materia Medica, University of Glasgow.
authors.forename: M S
authors.initials: MS
authors.lastname: Elfellah
authors.forename: R
authors.initials: R
authors.lastname: Dalling
authors.forename: I M
authors.initials: IM
authors.lastname: Kantola
authors.forename: J L
authors.initials: JL
authors.lastname: Reid
mesh_terms: D000293:Adolescent; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000328:Adult; D000368:Aged; D000375:Aging / Q000378:metabolism*; D001667:Binding, Competitive / Q000187:drug effects; D005260:Female; D006801:Humans; D008297:Male; D008790:Metoprolol / Q000494:pharmacology; D008875:Middle Aged; D009132:Muscles / Q000378:metabolism*; D011412:Propanolamines / Q000494:pharmacology; D011869:Radioligand Assay; D011943:Receptors, Adrenergic, beta / Q000032:analysis / Q000378:metabolism*
chemical_list: D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D011943:Receptors, Adrenergic, beta; C026777:ICI 118551; D008790:Metoprolol