Direct analysis of beta-adrenergic receptor subtypes on intact adult ventricular myocytes of the rat

Journal Article · Tue Jan 01 04:00:00 EST 1985 · Circ. Res.; (United States)

DOI:https://doi.org/10.1161/01.RES.56.1.126· OSTI ID:5829000

Buxton, I L; Brunton, L L

beta 1- and beta 2-Adrenergic receptors co-exist in the adult rat ventricle. Radioligand binding and cell purification techniques have been employed to determine the cellular origin of these receptors. The beta-adrenergic antagonist ligand (+/-)-(/sup 125/I) iodocyanopindolol binds to 2 X 10(5) receptors per purified adult rat cardiomyocyte, with a dissociation constant of 70 pM. The subtype-selective antagonists betaxolol (beta 1), practolol (beta 1), and zinterol (beta 2) compete for (/sup 125/I)iodocyanopindolol-binding sites on intact myocytes in monophasic manners with dissociation constants of 46, 845, and 923 nM, respectively. (/sup 125/I)iodocyanopindolol binding to membranes prepared from nonmyocyte elements of rat ventricle occurs with a dissociation constant of 43 pM and a capacity of 88 fmol/mg membrane protein. Computer analysis of competition of (/sup 125/I)iodocyanopindolol binding by betaxolol, practolol, and zinterol in nonmyocyte membranes demonstrates biphasic curves that comprise binding to both beta 1- and beta 2-receptors. These data demonstrate that purified adult ventricular myocytes possess only beta 1-receptors, and that the beta 2-receptors found in rat ventricle are located on nonmyocyte cell types.

• Research Organization: Univ. of California, San Diego, La Jolla
• OSTI ID: 5829000
• Journal Information: Circ. Res.; (United States), Journal Name: Circ. Res.; (United States) Vol. 56:1; ISSN CIRUA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BODY
CARDIOVASCULAR SYSTEM
CELL CONSTITUENTS
CELL CULTURES
CELL MEMBRANES
CHEMICAL ANALYSIS
CHEMICAL BONDS
COMPUTERS
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
HEART
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
LIGANDS
MAMMALS
MEMBRANES
NUCLEI
ODD-EVEN NUCLEI
ORGANS
RADIOISOTOPES
RATS
RECEPTORS
RODENTS
SYMPATHOMIMETICS
TRACER TECHNIQUES
VERTEBRATES