These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Evidence for internalization of the recognition site of beta-adrenergic receptors during receptor subsensitivity induced by (-)-isoproterenol.
    Author: Chuang DM, Costa E.
    Journal: Proc Natl Acad Sci U S A; 1979 Jun; 76(6):3024-8. PubMed ID: 223168.
    Abstract:
    In the supernatant (30,000 x g) of frog erythrocyte homogenates, by using gel filtration we detected a protein that could bind [(3)H]dihydroalprenolol ([(3)H]DHA) with high affinity. This binding was greatly enhanced when the erythrocytes were preincubated with (-)-isoproterenol. After various periods of incubation with (-)-isoproterenol, the extent of the increase in the density of [(3)H]DHA binding sites in the cytosol was paralleled by a proportional decrease in the number of [(3)H]DHA binding sites in the corresponding pellet; both events peaked after 2-3 hr of incubation with (-)-isoproterenol. The K(a) of the (-)-isoproterenol-induced increase in [(3)H]DHA binding in cytosol and the decrease in this binding in the membrane ranged between 60 and 90 nM. The changes in the cytosol and particulate [(3)H]DHA binding sites were independent of RNA and protein synthesis. The increase in cytosol binding elicited by (-)-isoproterenol was blocked by exposure of the cells to (-)-alprenolol which per se failed to change the cytosol binding of [(3)H]DHA. Scatchard analysis revealed that the enhanced [(3)H]DHA binding to cytosol material was due to a 4-fold increase in the B(max) with little or no change in K(d) ( approximately 9 nM). Binding displacement data show that these soluble [(3)H]DHA binding sites resemble the surface membrane recognition sites. Moreover, the ability of various beta-adrenergic agents to increase [(3)H]DHA binding to cytosol after they were incubated with frog erythrocytes paralleled their affinity for membrane-bound beta receptors. These findings support the view that the beta-adrenergic receptor desensitization caused by prolonged exposure to (-)-isoproterenol is due, at least in part, to an internalization of the recognition site of beta-adrenergic receptors.
    [Abstract] [Full Text] [Related] [New Search]