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Beta adrenergic receptor subtypes in the atria evidence for close coupling of beta 1 adrenergic and beta 2 adrenergic receptors to adenylate cyclase


, : Beta adrenergic receptor subtypes in the atria evidence for close coupling of beta 1 adrenergic and beta 2 adrenergic receptors to adenylate cyclase. Journal of Pharmacology & Experimental Therapeutics 238(3): 886-892

The relationship between occupancy of beta adrenergic receptors and stimulation of adenylate cyclase in dog atrial tissue was examined by studying the binding of [125I]iodopindolol and the activation of adenylate cyclase. Computer-assisted nonlinear regression analysis was used to analyze the inhibition of isoproterenol-stimulated adenylate cyclase activity by beta-1- or beta-2-selective antagonists. The Ki values for each subtype of receptor for the selective antagonists resulting from studies of the inhibition of adenylate cyclase activity were similar to those determined in studies of the inhibition of the binding of [125I] iodopindolol. To compare further the occupancy of beta-1 or beta-2 adrenergic receptors with the activation of adenylate cyclase mediated by each class of receptor, computer modeling of the stimulation of adenylate cyclase by the beta-1-selective agonist norepinephrine was carried out. The EC50 values of norepinephrine for each receptor subtype, as measured in studies of norepinephrine-stimulated adenylate cyclase activity, were similar to the Ki values for the inhibition by norepinephrine of the binding of [125I]iodopindolol to each receptor subtype. The data led to the conclusion that beta-1 adrenergic receptors make up about 70% of the total number of beta adrenergic receptors and mediate 70% of the increase in adenylate cyclase activity produced by isoproterenol. These results suggest that the relationship between occupancy of each class of receptor and activation of adenylate cyclase is linear and that, when agonist-stimulated adenylate cyclase activity is used as a functional response, neither spare beta-1 nor spare beta-2 adrenergic receptors exist in the atrium. Finally, a bromo-acetylated derivative of alprenolol, Alm-CO-CH2Br, was used to inactivate irreversibly beta adrenergic receptors in dog atria. In atrial membranes pretreated with different concentrations of Alm-CO-CH2Br, a decrease in receptor density correlated with a reduction in the maximal level of isoproterenol-stimulated adenylate cyclase activity. These experiments provide direct evidence that all of the beta adrenergic receptors in the atria are coupled to adenylate cyclase.

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Other references

Brincat M.P.; O.B.ien G.W.; Lisk M.; D.R.ig M.; George S.C., 2001: Hydrocarbon charge history of the northern Londonderry High; implications for trap integrity and future prospectivity. APPEA Journal 41(1): 483-496

Kerr, R.A., 1994: Contacts with the west bring cultural revolution. Science 264(5163): 1277-1279

Hodgson, N.W.; Waly, M.I.; Al-Farsi, Y.M.; Al-Sharbati, M.M.; Al-Farsi, O.; Ali, A.; Ouhtit, A.; Zang, T.; Zhou, Z.Sunny.; Deth, R.C., 2015: Decreased glutathione and elevated hair mercury levels are associated with nutritional deficiency-based autism in Oman. Genetic, nutrition, and environmental factors have each been implicated as sources of risk for autism. Oxidative stress, including low plasma levels of the antioxidant glutathione, has been reported by numerous autism studies, which can disrupt me...

Childers, J.; Surwit, E.; Hatch, K., 1994: Laparoscopic restaging of ovarian carcinoma. Gynecologic Oncology 52(1): 133

Nehring, K.; Schiemann, R.; Hoffmann, L.; Klippel, W., 1960: The utilisation of energy in feed in relation to plane of nutrition. 2. Experiments with pigs. For part 1 see Abst. 1166, Vol. 30. 2. There were 3 series of trials with 6, 4 and 8 castrated male pigs, 132 metabolism trials in all, each of 13 or 14 days with preliminary periods of similar length. For periods of 2 days the metabolism cages we...

Shurovenkov, Y.B.; Pushkarev, B.V., 1995: Trichogramma production and mechanization of dispersal. Aspects of the recent modernization and mechanization of the production and use of Trichogramma in Russia are described and evaluated, particularly in relation to: the rearing of the grain moth [Sitotroga cerealella]; 'focal' distributio...

Hulbert, E.M., 1968: Phytoplankton observations in the western Caribbean Sea. Bulletin of Marine Science, 18: 388-399

Lee, BY., 1987: Bionomics of the oak longicorn, Moechotypa diphysis Pascoe Coleoptera Cerambycidae, infesting the oak mushroom bed logs. Research Reports of the Forest Research Institute Korea, 139-145 No. 35

Holtzman, L.; Lezion, R., 1996: Endodontic treatment of maxillary canine with dens invaginatus and immature root. A conservative approach to endodontic treatment of a maxillary canine with dens invaginatus is presented. Pulp involvement and periapical abscess subsequent to contamination through the invagination space occurred at an early dental age before roo...

Faliski, J.B., 1962: Seasonal variables of the Phytocoenotic frontiers. Acta Soc Bot Poloniae 31(2): 239-263