title: Effects of chronic administration of agonists and antagonists on the density of beta-adrenergic receptors.
abstract: It is frequently hypothesized that drug-induced alterations in the density of beta-adrenergic receptors underlie tolerance to and physical dependence on agonists and antagonists at beta-adrenergic receptors. Two approaches to determining the effect of treatment with drugs on the density of beta-adrenergic receptors are described. In the first, the density of beta-adrenergic receptors was measured on leukocytes taken from human subjects during and after drug treatment. Treatment with the antagonist propranolol caused an increase in the density of beta-adrenergic receptors on leukocytes, whereas treatment with the agonists terbutaline and ephedrine, or pindolol, an antagonist with intrinsic sympathomimetic activity, caused a decrease in the density of beta-adrenergic receptors. In the second approach, the effect of agonists on the density of beta-adrenergic receptors on C6 glioma cells in culture was determined. Incubation with the full agonist isoproterenol decreased the density of both beta 1- and beta 2-adrenergic receptors. In contrast, incubation with pindolol or celiprolol, also an antagonist with intrinsic sympathomimetic activity, selectively decreased the density of beta 2-adrenergic receptors. Pindolol and celiprolol may be useful in situations in which selective stimulation of beta 2-adrenergic receptors and blockade of beta 1-adrenergic receptors is desirable.
authors.forename: K A
authors.initials: KA
authors.lastname: Neve
authors.forename: P B
authors.initials: PB
authors.lastname: Molinoff
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D017272:Celiprolol; D002478:Cells, Cultured; D004809:Ephedrine / Q000494:pharmacology; D006321:Heart / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007962:Leukocytes / Q000032:analysis / Q000187:drug effects; D010869:Pindolol / Q000494:pharmacology; D011412:Propanolamines / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D011943:Receptors, Adrenergic, beta / Q000032:analysis / Q000187:drug effects*; D013726:Terbutaline / Q000494:pharmacology
chemical_list: D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D011943:Receptors, Adrenergic, beta; D011433:Propranolol; D010869:Pindolol; D017272:Celiprolol; D004809:Ephedrine; D013726:Terbutaline