Identification of beta adrenergic receptors in rat hypothalamus.

Published

Journal Article

(-)-[3H]-Dihydroalprenolol((-)[3H]DHA) binding in the rat hypothalamus appears to possess all the characteristics expected of physiologically relevant beta-adrenergic receptors. Binding of (-)-[3H]DHA to the hypothalamic sites was rapid (k1 = 1.3 X 10(-7) min-1) and also rapidly reversible. Binding was saturable at low concentrations of ligand (approximately 50-100 nM). The dissociation constant (KD) of (-)-[3H]DHA binding determined by equilibrium analysis was 19 nM. Binding displayed beta-adrenergic specificity. beta-Adrenergic agonists inhibited binding in the following order of potency: (-)-isoproterenol congruent to (-)-epinephrine greater than (-)-norepinephrine. Specific beta-adrenergic antagonists (-)-propranol and (-)-alprenolol inhibited binding at low concentrations (KD = 25-50nM) whereas the alpha-antagonist phentolamine inhibited binding at very high concentration (KD = 42 micron). Interactions of both agonists and antagonists with the sites showed stereoselectivity. The (-)-isomers of all beta-adrenergic agents tested were more potent than their respective (+)-isomers. These results suggest that specific receptor sites for beta-adrenergic catecholamines are present in rat hypothalamus.

Full Text

Duke Authors

Cited Authors

  • Caron, MG; Gagne, B; De Lean, A

Published Date

  • July 1, 1977

Published In

Volume / Issue

  • 55 / 7

Start / End Page

  • 693 - 699

PubMed ID

  • 19139

Pubmed Central ID

  • 19139

International Standard Serial Number (ISSN)

  • 0008-4018

Digital Object Identifier (DOI)

  • 10.1139/o77-100

Language

  • eng

Conference Location

  • Canada