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Irreversible Blockade of Beta-adrenergic Receptors with a Bromoacetyl Derivative of Pindolol

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Specialty Pharmacology
Date 1985 Jan 1
PMID 2858822
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Abstract

A potent irreversible beta-adrenergic derivative of pindolol possessing a chemically reactive group (Br-AAM-pindolol) was synthesized. This compound devoid of agonist properties, competed for all (3H)-dihydroalprenolol (3H-DHA) binding sites in C6 glioma cell and rat cerebellum membranes. Pretreatment of C6 glioma cell membranes with Br-AAM-pindolol and subsequent washing resulted in a time- and dose-dependent blockade of beta-adrenergic receptors. A 50% blockade was achieved in the presence of 1.6 nM Br-AAM-pindolol. This blockade occurs specifically at the beta-adrenergic receptor level, as: 1) it induced a decrease of maximal isoproterenol stimulated adenylate cyclase activity with no modification of basal and sodium fluoride stimulated activity and 2) decreases of (3H)-DHA binding and stimulation of adenylate cyclase activity by the agonist were suppressed in the presence of isoproterenol, a beta-adrenergic agonist. Furthermore, Br-AAM-pindolol treatment did not affect (3H)-diazepam binding in C6 glioma cell membranes. Pretreatment of C6 glioma cells with Br-AAM-pindolol also reduced the response of adenylate cyclase to isoproterenol and the number of beta-adrenergic receptors. The blockade of beta-adrenergic receptors of C6 glioma cells by Br-AAM-pindolol was non-competitive, whereas the blockade obtained with AM-pindolol, a derivative of pindolol devoid of alkylating properties, was competitive. The irreversible blockade of beta-adrenergic receptors by Br-AAM-pindolol in rat erythrocyte membranes was substantiated by the demonstration that no recovery of beta-adrenergic receptors occurred during long term incubation of the membranes (48 h) following Br-AAM-pindolol treatment and subsequent washing.(ABSTRACT TRUNCATED AT 250 WORDS)

References
1.
Rashidbaigi A, Ruoho A . Iodoazidobenzylpindolol, a photoaffinity probe for the beta-adrenergic receptor. Proc Natl Acad Sci U S A. 1981; 78(3):1609-13. PMC: 319181. DOI: 10.1073/pnas.78.3.1609. View

2.
Venter J . High efficiency coupling between beta-adrenergic receptors and cardiac contractility: direct evidence for "spare" beta-adrenergic receptors. Mol Pharmacol. 1979; 16(2):429-40. View

3.
Burgermeister W, Hekman M, Helmreich E . Photoaffinity labeling of the beta-adrenergic receptor with azide derivatives of iodoccyanopindolol. J Biol Chem. 1982; 257(9):5306-11. View

4.
Broadley K, Nicholson C . Dissociation constants of isoprenaline and orciprenaline and their relative efficacies on guinea-pig isolated atria determined by use of an irreversible beta-adrenoceptor antagonist. Br J Pharmacol. 1981; 72(4):635-43. PMC: 2071640. DOI: 10.1111/j.1476-5381.1981.tb09143.x. View

5.
Shorr R, Heald S, JEFFS P, Lavin T, Strohsacker M, Lefkowitz R . The beta-adrenergic receptor: rapid purification and covalent labeling by photoaffinity crosslinking. Proc Natl Acad Sci U S A. 1982; 79(9):2778-82. PMC: 346289. DOI: 10.1073/pnas.79.9.2778. View