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Direct analysis of beta-adrenergic receptor subtypes on intact adult ventricular myocytes of the rat
- Source :
- Circulation research. 56(1)
- Publication Year :
- 1985
-
Abstract
- beta 1- and beta 2-Adrenergic receptors co-exist in the adult rat ventricle. We have employed radioligand binding and cell purification techniques to determine the cellular origin of these receptors. The beta-adrenergic antagonist ligand (+/-)-[125I] 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 [125I]iodocyanopindolol-binding sites on intact myocytes in monophasic manners with dissociation constants of 46, 845, and 923 nM, respectively. [125I]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 [125I]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.
- Subjects :
- Male
medicine.medical_specialty
Adrenergic receptor
Physiology
Adrenergic beta-Antagonists
Iodocyanopindolol
Betaxolol
Iodine Radioisotopes
Propanolamines
chemistry.chemical_compound
Radioligand Assay
Internal medicine
Receptors, Adrenergic, beta
medicine
Animals
Zinterol
Receptor
Beta (finance)
Practolol
Cells, Cultured
Binding Sites
Chemistry
Myocardium
Heart
Rats, Inbred Strains
Adrenergic beta-Agonists
Rats
Dissociation constant
Endocrinology
Ethanolamines
Pindolol
Biophysics
Cardiology and Cardiovascular Medicine
medicine.drug
Subjects
Details
- ISSN :
- 00097330
- Volume :
- 56
- Issue :
- 1
- Database :
- OpenAIRE
- Journal :
- Circulation research
- Accession number :
- edsair.doi.dedup.....77715a0e2cd6ca88e963b9898b4fa582