GTP-dependent inhibition of cardiac adenylate cyclase by muscarinic cholinergic agonists
- 55 Downloads
In membrane-containing particles of rabbit myocardium, inhibition of adenylate cyclase (EC 18.104.22.168) by cholinergic agonists was studied. The cholinergic agonists, in the potency order oxotremorine > acetylcholine > carbachol, reduced basal adenylate cyclase activity with half-maximal effects at about 0.3, 1 and 3 μM, respectively; maximal inhibition observed was about 40%. The enzyme inhibition occurred without apparent lag phase and was reversed by the muscarinic cholinergic antagonist, atropine, which finding indicates that muscarinic cholinergic receptors are involved in this process.
As for stimulation of cardiac adenylate cyclase by the β-adrenergic agonist, isoproterenol, the addition of GTP was necessary for maximal enzyme inhibition by the cholinergic agonists. The effects of GTP were half-maximal at about 0.2 and 1 μM and maximal at about 3 and 30 μM GTP for stimulation and inhibition, respectively. NaCl, which increased cardiac adenylate cyclase activity, facilitated the GTP-dependent cholinergic inhibition; the NaCl effect was maximal between 50 and 100 mM.
In the presence of GTP, the cholinergic agonist, carbachol, not only reduced basal adenylate cyclase activity, but also inhibited adenylate cyclase stimulated by isoproterenol (100 μM) or NaF (10 mM). In the presence of cholera toxin (40 μg/ml), the GTP-induced activation of the enzyme was counteracted by carbachol. However, the stable GTP-analogues, guanylyl-5′-imidodiphosphate and guanosine-5′-O-(3-thiotriphosphate), which caused a persistent adenylate cyclase activation, reversed or prevented the carbachol-induced inhibition.
The data indicate that cholinergic agonists inhibit cardiac adenylate cyclase by a process that requires (the hydrolyzable) GTP and involves sodium ions.
Key wordsMyocardium Muscarinic cholinergic receptors Adenylate cyclase inhibition Guanine nucleotides Sodium
Unable to display preview. Download preview PDF.
- Aktories, K., Jakobs, K. H.: GTP-dependent inhibition of cardiac adenylate cyclase by muscarinic cholinergic receptor stimulation. Hoppe Seylers Z. Physiol. Chem. 360, 223 (1979)Google Scholar
- Aktories, K., Schultz, G., Jakobs, K. H.: Inhibition of hamster fat cell adenylate cyclase by prostaglandin E1 and epinephrine: Requirement for GTP and sodium ions. FEBS Lett. 107, 100–104 (1979)Google Scholar
- Birnbaumer L: The actions of hormones and nucleotides on membrane-bound adenylyl cyclases: An overview. In: Receptors and hormone action, Vol. 1 (B. W. O'Malley, L. Birnbaumer, eds.), pp. 485–547. New York, London: Academic Press 1977Google Scholar
- Cassel, D., Selinger, Z.: Catecholamine-stimulated GTPase activity in turkey erythrocyte membranes. Biochim. Biophys. Acta 452, 538–551 (1976)Google Scholar
- Cassel, D., Selinger, Z.: Mechanism of adenylate cyclase activation by cholera toxin: Inhibition of GTP hydrolysis at the regulatory site. Proc. Natl. Acad. Sci. USA 74, 3307–3311 (1977)Google Scholar
- Cassel, D., Selinger, Z.: Mechanism of adenylate cyclase activation through the β-adrenergic receptor: Catecholamine-induced displacement of bound GDP. Proc. Natl. Acad. Sci. USA 75, 4155–4159 (1978)Google Scholar
- Cavey, D., Vincent, J. P., Làzdunski, M.: The muscarinic receptor of heart cell membranes. FEBS Lett. 84, 110–114 (1977)Google Scholar
- Fields, J. Z., Roeske, W. R. Morkin, E., Yamamura, H. I.: Cardiac muscarinic cholinergic receptors. Biochemical identification and characterization. J. Biol. Chem. 253, 3251–3258 (1978)Google Scholar
- Galper, J. B., Smith, T. W.: Properties of muscarinic acetylcholine receptors in heart cell cultures. Proc. Natl. Acad. Sci. USA 75, 5831–5835 (1978)Google Scholar
- Galper, J. B., Klein, W., Caterall, W. A.: Muscarinic acetylcholine receptors in developing chick heart. J. Biol. Chem. 252, 8692–8699 (1977)Google Scholar
- George, W. J., Polson, J. B., O'Toole, A. G., Goldberg, N. D.: Elevation of guanosine 3′,5′-cyclic phosphate in rat heart after perfusion with acetylcholine. Proc. Natl. Acad. Sci. USA 66, 398–403 (1970)Google Scholar
- George, W. J., Wilkerson, R. D., Kadowitz, P. J.: Influence of acetylcholine on contractile force and cyclic nucleotide levels in the isolated perfused rat heart. J. Pharmacol. Exp. Ther. 184, 228–235 (1972)Google Scholar
- Jakobs K. H.: GTP-dependent inhibition of platelet adenylate cyclase by α-adrenergic agonists. In: Proceedings of the 12th FEBS Meeting, cyclic nucleotides and protein phosphorylation in cell regulation, Vol. 54 (E.-G. Krause, L. Pinna, A. Wollenberger, eds.), pp. 11–20. Oxford: Pergamon Press 1979Google Scholar
- Jakobs, K. H., Saur, W. Schultz, G.: Reduction of adenylate cyclase activity in lysates of human platelets by the alpha-adrenergic component of epinephrine. J. Cyclic Nucleotide Res. 2, 381–392 (1976)Google Scholar
- Jakobs, K. H., Saur, W., Schultz, G.: Inhibition of platelet adenylate cyclase by epinephrine requires GTP. FEBS Lett. 85, 167–170 (1978)Google Scholar
- LaRaia, P. J., Sonnenblick, E. H.: Autonomic control of cardiac cAMP. Circ. Res. 28, 377–384 (1971)Google Scholar
- Londos, C., Cooper, D. M. F., Schlegel, W., Rodbell, M.: Adenosine analogs inhibit adipocyte adenylate cyclase by a GTP-dependent process: Basis for actions of adenosine and methylxanthines on cyclic AMP production and lipolysis. Proc. Natl. Acad. Sci. USA 75, 5362–5366 (1978)Google Scholar
- Lowry, O. H., Rosebrough, N. J., Farr, A. L., Randall, R. J.: Protein measurement with the Folin phenol reagent. J. Biol. Chem. 193, 265–275 (1951)Google Scholar
- Murad, F., Chi, Y.-M., Rall, T. W., Sutherland, E. W.: Adenyl cyclase. III. The effect of catecholamines and choline esters on the formation of adenosine 3′,5′-phosphate by preparations from cardiac muscle and liver. J. Biol. Chem. 237, 1233–1238 (1962)Google Scholar
- Rodbell, M.: The role of nucleotide regulatory components in the coupling of hormone receptors and adenylate cyclase. In: Molecular biology and pharmacology of cyclic nucleotides (G. Folco, R. Paoletti, eds.), pp. 1–12. Amsterdam, New York: Elsevier/North-Holland 1978Google Scholar
- Sabol, S. L., Nirenberg, M.: Regulation of adenylate cyclase of neuroblastoma x glioma hybrid cells by α-adrenergic receptors. I. Inhibition of adenylate cyclase mediated by α receptors. J. Biol. Chem. 254, 1913–1920 (1979)Google Scholar
- Tsien, R. W.: Cyclic AMP and contractile activity in heart. In: Advances in cyclic nucleotide research, Vol. 8 (P. Greengard, G. A. Robison, eds.), pp. 363–420. New York: Raven Press 1977Google Scholar
- Walseth, R. F., Johnson, R. A.: The enzymatic preparation of [α-32P]nucleoside triphosphates, cyclic [32P]AMP, and cyclic [32P]GMP. Biochim. Biophys. Acta 562, 11–31 (1979)Google Scholar
- Watanabe, A. M., McConnaughey, M. M., Strawbridge, R. A., Fleming, J. W., Jones, L. R., Besch, H. R., Jr.: Muscarinic cholinergic receptor modulation of β-adrenergic receptor affinity for catecholamines. J. Biol. Chem. 253, 4833–4836 (1978)Google Scholar
- Yamamura, H., Lad, P. M., Rodbell, M.: GTP stimulates and inhibits adenylate cyclase in fat cell membranes through distinct regulatory processes. J. Biol. Chem. 252, 7964–7966 (1977)Google Scholar