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Interactions of agonists with platelet alpha 2-adrenergic receptors.

Publication ,  Journal Article
Hoffman, BB; Michel, T; Brenneman, TB; Lefkowitz, RJ
Published in: Endocrinology
March 1982

Epinephrine induces human platelet aggregation by interacting with alpha-adrenergic receptors. These sites were demonstrated by radioligand-binding techniques using the new antagonist ligand, [3H]yohimbine. The sites labeled by [3H]yohimbine had the specificity of alpha 2-receptors with the affinity of yohimbine much greater than prazosin. Epinephrine-mediated inhibition of prostaglandin E1-stimulated adenylate cyclase activity in human platelet lysates was also found to have an alpha 2-receptor specificity. Competition curves of antagonists with [3H]yohimbine indicated a homogeneous population of alpha 2-receptors. In contrast, competition curves of a series of full and partial agonists with [3H]yohimbine were resolved into two distinct affinity states; the ratio of the dissociation constants of agonists for the low and high affinity states was positively correlated with the agonist's intrinsic activity for inhibition of adenylate cyclase. Guanine nucleotides were found to destabilize the high affinity form of the alpha 2-receptors. At high nucleotide concentrations, all high affinity states of the receptor were converted to the low affinity form. The formation of the high affinity agonist-binding state may reflect an interaction between the agonist-receptor complex and an additional membrane component, and probably reflects events involved in alpha 2-receptor-adenylate cyclase coupling.

Duke Scholars

Published In

Endocrinology

DOI

ISSN

0013-7227

Publication Date

March 1982

Volume

110

Issue

3

Start / End Page

926 / 932

Location

United States

Related Subject Headings

  • Yohimbine
  • Receptors, Adrenergic, alpha
  • Receptors, Adrenergic
  • Prostaglandins E
  • Prazosin
  • Phentolamine
  • Norepinephrine
  • Kinetics
  • Humans
  • Guanylyl Imidodiphosphate
 

Citation

APA
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ICMJE
MLA
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Hoffman, B. B., Michel, T., Brenneman, T. B., & Lefkowitz, R. J. (1982). Interactions of agonists with platelet alpha 2-adrenergic receptors. Endocrinology, 110(3), 926–932. https://doi.org/10.1210/endo-110-3-926
Hoffman, B. B., T. Michel, T. B. Brenneman, and R. J. Lefkowitz. “Interactions of agonists with platelet alpha 2-adrenergic receptors.Endocrinology 110, no. 3 (March 1982): 926–32. https://doi.org/10.1210/endo-110-3-926.
Hoffman BB, Michel T, Brenneman TB, Lefkowitz RJ. Interactions of agonists with platelet alpha 2-adrenergic receptors. Endocrinology. 1982 Mar;110(3):926–32.
Hoffman, B. B., et al. “Interactions of agonists with platelet alpha 2-adrenergic receptors.Endocrinology, vol. 110, no. 3, Mar. 1982, pp. 926–32. Pubmed, doi:10.1210/endo-110-3-926.
Hoffman BB, Michel T, Brenneman TB, Lefkowitz RJ. Interactions of agonists with platelet alpha 2-adrenergic receptors. Endocrinology. 1982 Mar;110(3):926–932.
Journal cover image

Published In

Endocrinology

DOI

ISSN

0013-7227

Publication Date

March 1982

Volume

110

Issue

3

Start / End Page

926 / 932

Location

United States

Related Subject Headings

  • Yohimbine
  • Receptors, Adrenergic, alpha
  • Receptors, Adrenergic
  • Prostaglandins E
  • Prazosin
  • Phentolamine
  • Norepinephrine
  • Kinetics
  • Humans
  • Guanylyl Imidodiphosphate