Investigation of cardiac beta-adrenoceptors using 125I-labelled 1-(4-iodophenoxy)-3-isopropylaminopropan-2-ol

European Journal of Pharmacology
E A WoodcockC I Johnston

Abstract

1-(4-iodophenoxy)-3-isopropylaminopropan-2-ol (IIP) is a potent beta-adrenergic antagonist which has been labelled to high specific activity with 125I and used to bind to rat myocardial membranes. The characteristics of binding were consistent with the known properties of beta-receptors. Thus, binding was highly stereospecific for the L-stereoisomer since L-propranolol was two orders of magnitude more potent than the D-isomer in competing for these sites. The beta-adrenergic agonists isoproterenol, epinephrine and norepinephrine competed for binding with potencies paralleling their pharmacological potencies as beta-adrenergic effectors. The dissociation constant for binding of IIP was 4--5 nM as measured either by direct binding studies or by its inhibition of isoproterenol stimulated adenylate cyclase. Binding was saturable with 0.06 pmoles of IIP per mg of membrane protein binding at saturation. 125IIP is a high affinity, high specific activity ligand suitable for use as a selective probe for the detection and quantitation of cardiac beta-receptors. Its introduction should help solve the problems involved in the investigation of myocardial beta-adrenergic receptors.

References

Mar 1, 1975·Biochemical Pharmacology·R J Lefkowitz
Apr 1, 1975·Proceedings of the National Academy of Sciences of the United States of America·R W AlexanderR J Lefkowitz
Apr 8, 1974·Biochemical and Biophysical Research Communications·G P Tell, P Cuatrecasas
Aug 30, 1974·Nature·G KunosM Nickerson
Apr 2, 1971·Biochemical and Biophysical Research Communications·G S Levey
Mar 16, 1968·Nature·G Kunos, M Szentivanyi
Jan 24, 1973·Nature: New Biology·G KunosM Nickerson
Jul 1, 1974·Proceedings of the National Academy of Sciences of the United States of America·A LevitzkiM L Steer
Oct 1, 1974·Proceedings of the National Academy of Sciences of the United States of America·D AtlasA Levitzki
Feb 10, 1967·Annals of the New York Academy of Sciences·R F Furchgott
Apr 1, 1969·Circulation Research·B E SobelJ Ross

Citations

Sep 1, 1978·Clinical and Experimental Pharmacology & Physiology·E A WoodcockC I Johnston

Related Concepts

Adenylate Cyclase
Adrenergic beta-Agonists
Adrenergic beta-Antagonists
Metazoa
Plasma Membrane
Heart
Iodobenzenes
Myocardium
Propanolamines
Rexigen

Related Feeds

Adrenergic Receptors: Trafficking

Adrenergic receptor trafficking is an active physiological process where adrenergic receptors are relocated from one region of the cell to another or from one type of cell to another. Discover the latest research on adrenergic receptor trafficking here.