PMID: 6168833May 1, 1981Paper

Subtype specificity of alpha-adrenergic receptors in rat heart

Journal of Cardiovascular Pharmacology
R S WilliamsR J Lefkowitz

Abstract

Recent studies suggest that two subtypes of alpha-adrenergic receptors (alpha 1 and alpha 2) can be distinguished on the basis of the differential affinities of certain adrenergic ligands for each subtype. We have investigated the binding characteristics of several such ligands for alpha-adrenergic receptors in membrane preparations derived from rat heart. alpha-Adrenergic antagonists competed for binding sites identified by the nonsubtype selective alpha-adrenergic ligand [3H]dihydroergocryptine (DHE) in the order of potency expected for alpha 1-receptors, namely, prazosin (EC50 = 0.35 nM) greater than phentolamine (EC50 = 37 nM) greater than yohimbine (EC50 = 918 nM). Furthermore, the nonsubtype selective radioligand [3H]DHE identified a quantitatively similar number of specific binding sites in rat cardiac membranes as the alpha 1-selective radioligand [3H]prazosin (33 and 36 fmoles/mg protein, respectively), while the alpha 2-selective ligand [3H]clonidine at concentrations up to 20 nM demonstrated negligible specific binding. We conclude that the alpha-adrenergic receptors of rat heart homogenates demonstrate binding characteristics typical of alpha 1-receptors. While we cannot exclude the presence of small numbers of alph...Continue Reading

Citations

Jun 1, 1985·Naunyn-Schmiedeberg's Archives of Pharmacology·G Gross, I Lues
Aug 1, 1985·Heart and Vessels·G TsujimotoB B Hoffman
Jan 1, 1983·International Journal of Developmental Neuroscience : the Official Journal of the International Society for Developmental Neuroscience·M J Morris, E A Woodcock
Mar 1, 1994·British Journal of Pharmacology·O PérezJ Tamargo
Sep 1, 1984·Circulation Research·H J MotulskyP A Insel
Jun 1, 1984·Journal of Autonomic Pharmacology·F J MiñanoJ A Duran
Dec 1, 1982·Journal of Autonomic Pharmacology·L H TungW J Louis
Jan 31, 2006·Molecular and Cellular Biochemistry·Shahrzad JalaliNasrin Mesaeli
Feb 1, 1984·British Journal of Pharmacology·F M Tayo
Jan 1, 1983·Biochemical Pharmacology·G L StilesR J Lefkowitz
Jun 15, 1984·Biochemical Pharmacology·T SkomedalJ B Osnes

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