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: Binding characteristics of 3H-dihydroalprenolol to beta-adrenoceptors of rat heart treated with neuraminidase.
    Author: Nagatomo T, Sasaki M, Tsuchihashi H, Imai S.
    Journal: Jpn J Pharmacol; 1983 Aug; 33(4):851-7. PubMed ID: 6314011.
    Abstract:
    Binding characteristics of the beta-blockers and beta-agonists with the beta-adrenoceptors were investigated in 3H-dihydroalprenolol (3H-DHA) binding to rat heart membranes treated with neuraminidase. When 60% of the total sialic acid content in the membranes was removed, reproducibility of the binding assay became much better than was attainable without neuraminidase treatment, and the maximum density of beta-adrenoceptors was increased. These data suggest that the binding of the test compounds with the beta-adrenergic receptors in cardiac muscle was under the influence of the sialic acid of the glycocalyx of the membrane. The 3H-DHA binding sites in membranes treated with neuraminidase showed a strict stereo-specificity when tested with propranolol. The ranking order of inhibition of beta-antagonists or agonists is: dl-propranolol greater than oxprenolol greater than alprenolol greater than pindolol greater than YM-09538 greater than labetalol greater than acebutolol greater than atenolol greater than metoprolol greater than sotalol greater than butoxamine greater than practolol as antagonists or l-isoproterenol greater than l-epinephrine greater than l-norepinephrine as agonists. A good correlation (r = 0.91, P less than 0.001) was observed between the Ki values observed by the present binding assay and the pA2 observed in the guinea-pig atria relative to the positive inotropic effect by Bieth et al. (Br. J. Pharmacol. 68, 563-569, 1980), indicating that the present method will be useful for screening new beta-adrenergic receptor antagonists or agonists.
    [Abstract] [Full Text] [Related] [New Search]