Summary
Long-term β-adrenergic stimulation has been shown to desensitize the β-adrenoceptor/adenylyl cyclase signalling pathway at both the receptor and the G-protein level. To further elucidate the cellular mechanism of G-protein regulation we investigated the influence of prolonged infusion of isoprenaline (2.4 mg/kg·d) on myocardial mRNA levels of different G-protein α-subunits in rats. For comparison rats were treated with triiodothyronine (T3; 0.5 mg/kg·d) which induces cardiac hypertrophy like isoprenaline but has different effects on the adenylyl cyclase system. Isoprenaline- and T3-treated animals developed an increase in heart/body weight ratio of 41±3% and 27±4%, respectively (P<0.05). Isoprenaline increased myocardial total RNA concentration by 39±6% (P<0.05). Hybridization with 32P-labeled rat cDNAs demonstrated an expression rank order of Gsα-mRNA>Giα-2-mRNA>Giα−3-mRNA and no detectable expression of Giα−1-mRNA in rat myocardium. mRNA levels of Gsα Giα−2 and Giα−3 were 36.9±1.28, 10.7±1.07 and 3.7±0.19 pg/μg total RNA, respectively. Isoprenaline increased Giα−2 − and Giα−3-mRNA concentrations per μg total RNA by 49±18% and 27±710, respectively (P<0.05). This effect was abolished by simultaneously administered propranolol (9.9 mg/kg·d), indicating a,β-adrenoceptor-mediated mechanism. In contrast, T3-induced cardiac hypertrophy was not accompanied by changes in Giα-mRNA expression. Gsaα-mRNA levels were unaffected by either treatment.
In conclusion, long-term stimulation with isoprenaline in vivo induces a β-adrenoceptor-mediated increase in myocardial Giα−2 − and Giα−3-mRNA without affecting Gsα-mRNA. These results suggest that similar increases in myocardial Giα−2-mRNA in end-stage human heart failure may be at least partly explained by increased β-adrenergic stimulation due to increased sympathetic activity.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Auffray C, Rougeon F (1980) Purification of mouse immunoglobulin heavy-chain messenger RNAs from total myeloma tumor RNA. Eur J Biochem 107:303–314
Böhm M, Gierschik P, Jakobs KH, Pieske B, Schnabel P, Ungerer M, Erdmann E (1990) Increase of Giα in human hearts with dilated but not ischemic cardiomyopathy. Circulation 82:1249–1265
Bradford MM (1976) A rapid and sensitive method for quantification of microgram quantities of protein utilizing the principle of proteindye binding. Anal Biochem 72:248–254
Brann MR, Collins RM, Spiegel A (1987) Localization of mRNAs encoding the α-subunits of signal-transducing G-proteins within rat brain and among peripheral tissues. FEBS Lett 222:191–198
Chang HY, Klein RM, Kunos G (1982) Selective desensitization of cardiac beta adrenoceptors by prolonged in vivo infusion of catecholamines in rats. J Pharmacol Exp Ther 221:784–789
Clark RB, Kunkel MW, Friedman J, Goka TJ, Johnson JA (1988) Activation of cAMP-dependent protein kinase is required for heterologous desensitization of adenylyl cyclase in S49 wild-type lymphoma cells. Proc Nall Acad Sci USA 85:1442–1446
Cohn JN, Levine TB, Olivari MT, Garberg V, Lura D, Francis GS, Simon AB, Rector T (1984) Plasma norepinephrine as guide to prognosis in patients with congestive heart failure. N Engl J Med 311:819–823
Daly PA, Sole MJ (1990) Myocardial catecholamines and the pathophysiology of heart failure. Circulation 82 [Suppl I]:35–43
Eschenhagen T, Nose M, Schmitz W, Scholz H, Haverich A, Hirt S, Döring V, Kalmdr P (1991) Increased mRNA level of the α-subunit of inhibitory G-proteins in end-stage myocardial failure. Brit J Pharmacol (in press) (abstr)
Feldman AM, Cates AE, Veazey WB, Hershberger RE, Bristow MR, Baughma KL, Baumgartner WA, Van Dop C (1988) Increase in the 40000-mol wt pertussis toxin substrate (G-protein) in the failing human heart. J Clin Invest 82:189–197
Feldman AM, Cates AE, Bristow MR, Van Dop C (1989) Altered expression of alpha-subunits of G-proteins in failing human hearts. J Mol Cell Cardiol 21:359–365
Hadcock JR, Malbon CC (1988) Down-regulation of /gb-adrenergic receptors: agonist-induced reduction in receptor mRNA levels. Proc Natl Acad Sci USA 85:5021–5025
Hadcock JR, Ros M, Watkins DC, Malbon CC (1990) Cross-regulation between G-protein-mediated pathways. J Biol Chem 265: 14784–14790
Hausdorff WP, Caron MG, Lefkowitz RJ (1990) Turning off the signal: desensitization of β-adrenergic receptor function. FASEB J 4:2881–2889
Hayes JS, Pollock GD, Fuller RW (1984) In vivo cardiovascular responses to isoproterenol, dopamine and tyramine after prolonged infusion of isoproterenol. J Pharmacol Exp Ther 231:633–639
Hayes JS, Wyss VL, Schenck KS, Cohen ML (1986) Effects of prolonged isoproterenol infusion on cardiac and vascular response to adrenoceptor agonists. J Pharmacol Exp Ther 237:757–763
Herrin DL, Schmidt GW (1988) Rapid, reversible staining of northern blots prior to hybridization. BioTechniques 6:196–198
Holmer SR, Stevens S, Homcy CJ (1989) Tissue- and species-specific expression of inhibitory guanine nucleotide-binding proteins. Circ Res 65:1136–1140
Johnson MD, Grignolo A, Kuhn CM, Schanberg SM (1983) Hypertension and cardiovascular hypertrophy during chronic catecholamine infusion in rats. Life Sci 33:169–180
Jones DT, Reed RR (1987) Molecular cloning of five GTP-binding protein cDNA species from rat olfactory neuroepithelium. J Biol Chem 262:14241–14249
Katoh Y, Komuro I, Takaku F, Yamaguchi H, Yazaki Y (1990) Messenger RNA levels of guanine nucleotide-binding proteins are reduced in the ventricle of cardiomyopathic hamsters. Circ Res 67: 235–239
Kozasa T, Itoh H, Tsukamoto T, Kaziro Y (1988) Isolation and characterization of the human Gsα gene. Proc Natl Acad Sci USA 85:2081–2085
Lamph WW Dwarki VJ, Ofir R, Momminy M, Verma IM (1990) Negative and positive regulation by transcription factor cAMP response element-binding protein is modulated by phosphorylation. Proc Natl Acad Sci USA 87:4320–4324
Longabaugh JP, Vatner DE, Vatner SF, Homcy CJ (1988) Decreased stimulatory guanosine triphosphate binding protein in dogs with pressure-overload left ventricular failure. J Clin Invest 81:420–424
Longabaugh JP, Didsbury J, Spiegel A, Stiles GL (1989) Modification of the rat adipocyte A1 adenosine receptor-adenylate cyclase system during chronic exposure to an A1 adenosine receptor agonist: alterations in the quantity of Gsα- and Giα are not associated with changes in their mRNAs. Mol Pharmacol 36:681–688
Malbon CC, Rapiejko PJ, Watkins DC (1988) Permissive hormone regulation of hormone-sensitive effector systems. Trends Pharmacol Science 9:33–36
Neer E, Clapham DE (1988) Roles of G protein subunits in transmembrane signalling. Nature 333:129–134
Neumann J, Schmitz W, Scholz H, Meyerinck L von, Daring V, Kalmár P (1988) Increase of myocardial Gi-proteins in human heart failure. Lancet 11:936–937
Parsons WJ, Stiles GL (1987) Heterologous desensitization of the inhibitory A1 adenosine receptor-adenylate cyclase system in rat adipocytes. J Biol Chem 262:841–847
Rapiejko PJ, Watkins DC, Ros M, Malbon CC (1990) G-protein subunit mRNA levels in rat heart, liver and adipose tissue: analysis by DNA-excess solution hybridization. Biochim Biophys Acta 1052:348–350
Reithmann C, Gierschik P, Sidiropoulos D, Werdan K, Jakobs KH (1989) Mechanism of noradrenaline-induced heterologous desensitization of adenylate cyclase stimulation in rat heart muscle cells: increase in the level of inhibitory G-protein α-subunits. Eur J Pharmacol 172:211–221
Reithmann C, Gierschik P, Müller U, Werdan K, Jakobs KH (1990) Pseudomonas exotoxin A prevents β-adrenoceptor-induced upregulation of Gi protein α-subunits and adenylate cyclase desensitization in rat heart muscle cells. Mol Pharmacol 37:631–638
Sambrook J, Fritsch EF, Maniatis T (1989) Molecular cloning — a laboratory manual, 2nd edn. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY
Sanford CF, Griffin EE, Wildenthal K (1978) Synthesis and degradation of myocardial protein during the development and regression of thyroxine-induced cardiac hypertrophy in rats. Circ Res 43:688–694
Schnabel P, Böhm M, Gierschik P, Jakobs KH, Erdmann E (1990) Improvement of cholera toxin-catalysed ADP-ribosylation by endogenous ADP-ribosylation factor from bovine brain provides evidence for an unchanged amount of G5a in failing human myocardium. J Mol Cell Cardiol 22:73–82
Sibley DR, Lefkowitz RJ (1985) Molecular mechanisms of receptor desensitization using the β-adrenergic receptor-coupled adenylate cyclase system as a model. Nature 317:124–129
Stanton HC, Brenner G, Mayfield ED (1969) Studies on isoproterenol-induced cardiomegaly in rats. Am Heart J 77:72–80
Tse J, Powell JR, Baste CA, Priest RE, Kuo JF (1979) Isoproterenol-induced cardiac hypertrophy: modifications in characteristics of β-adrenergic receptor, adenylate cyclase, and ventricular contraction. Endocrinology 105:246–255
Weinstein LS, Spiegel AM, Carter AD (1988) Cloning and characterization of the human gene of the a-subunit of Gi2, a GTP-binding signal transducing protein. FEBS Lett 232:333–340
Zierhut W, Zimmer HG (1989) Significance of myocardial α- and, β-adrenoceptors in catecholamine-induced cardiac hypertrophy. Circ Res 65:1417–1425
ZimmerHG, Peffer H (1986) Metabolic aspects of the development of experimental cardiac hypertrophy. Basic Res Cardiol 81 [Suppl 1]:127–137
Author information
Authors and Affiliations
Additional information
Parts of this work were presented at the wintermeeting of the Deutsche Gesellschaft fur Pharmakologie und Toxikologie in Hannover, 1990 (Eschenhagen et al.), Naunyn-Schmiedebergs Arch Pharmacol 342 (Suppl):R8. The work was supported by the Deutsche Forschungsgemcinschaft
Send offprint requests to: T. Eschenhagen at the above address
Rights and permissions
About this article
Cite this article
Eschenhagen, T., Mende, U., Nose, M. et al. Isoprenaline-induced increase in mRNA levels of inhibitory G-protein α-subunits in rat heart. Naunyn-Schmiedeberg's Arch Pharmacol 343, 609–615 (1991). https://doi.org/10.1007/BF00184292
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00184292