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Lorenz K, Rosner MR, Brand T, Schmitt JP. Raf kinase inhibitor protein: lessons of a better way for β-adrenergic receptor activation in the heart. J Physiol 2017; 595:4073-4087. [PMID: 28444807 PMCID: PMC5471367 DOI: 10.1113/jp274064] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 02/27/2017] [Indexed: 12/13/2022] Open
Abstract
Stimulation of β-adrenergic receptors (βARs) provides the most efficient physiological mechanism to enhance contraction and relaxation of the heart. Activation of βARs allows rapid enhancement of myocardial function in order to fuel the muscles for running and fighting in a fight-or-flight response. Likewise, βARs become activated during cardiovascular disease in an attempt to counteract the restrictions of cardiac output. However, long-term stimulation of βARs increases the likelihood of cardiac arrhythmias, adverse ventricular remodelling, decline of cardiac performance and premature death, thereby limiting the use of βAR agonists in the treatment of heart failure. Recently the endogenous Raf kinase inhibitor protein (RKIP) was found to activate βAR signalling of the heart without adverse effects. This review will summarize the current knowledge on RKIP-driven compared to receptor-mediated signalling in cardiomyocytes. Emphasis is given to the differential effects of RKIP on β1 - and β2 -ARs and their downstream targets, the regulation of myocyte calcium cycling and myofilament activity.
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Affiliation(s)
- Kristina Lorenz
- Comprehensive Heart Failure CenterUniversity of WürzburgVersbacher Straße 997078WürzburgGermany
- West German Heart and Vascular Center EssenUniversity Hospital EssenHufelandstraße 5545147EssenGermany
- Leibniz‐Institut für Analytische Wissenschaften – ISAS – e.V.Bunsen‐Kirchhoff‐Straße 1144139DortmundGermany
- Institute of Pharmacology and ToxicologyUniversity of WürzburgVersbacher Straße 997078WürzburgGermany
| | - Marsha Rich Rosner
- Ben May Department for Cancer ResearchUniversity of ChicagoChicagoIL 60637USA
| | - Theresa Brand
- Leibniz‐Institut für Analytische Wissenschaften – ISAS – e.V.Bunsen‐Kirchhoff‐Straße 1144139DortmundGermany
- Institute of Pharmacology and ToxicologyUniversity of WürzburgVersbacher Straße 997078WürzburgGermany
| | - Joachim P Schmitt
- Institute of Pharmacology and Clinical PharmacologyDüsseldorf University HospitalUniverstitätsstraße 140225DüsseldorfGermany
- Cardiovascular Research Institute Düsseldorf (CARID)Heinrich‐Heine‐UniversityUniverstitätsstraße 140225DüsseldorfGermany
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2
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Lu Y, Jung JH, Lee HJ, Moon BS, Lee BC, Kim SE. Synthesis andIn VivoEvaluation of a Kit-Type99mTc-labeledN-(2-Aminoethyl)-3-(4-(2-hydroxy-3-(isopropylaminopropoxy)phenyl)propanamide as a Selective β1-Adrenoceptor-binding SPECT Radiotracer. B KOREAN CHEM SOC 2016. [DOI: 10.1002/bkcs.11027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Yingqing Lu
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology; Seoul National University; Seoul 08826 Korea
| | - Jae Ho Jung
- Department of Nuclear Medicine, Seoul National University College of Medicine; Seoul National University Bundang Hospital; Seongnam 13620 Korea
| | - Hong Jin Lee
- Department of Nuclear Medicine, Seoul National University College of Medicine; Seoul National University Bundang Hospital; Seongnam 13620 Korea
| | - Byung Seok Moon
- Department of Nuclear Medicine, Seoul National University College of Medicine; Seoul National University Bundang Hospital; Seongnam 13620 Korea
| | - Byung Chul Lee
- Department of Nuclear Medicine, Seoul National University College of Medicine; Seoul National University Bundang Hospital; Seongnam 13620 Korea
- Center for Nanomolecular Imaging and Innovative Drug Development; Advanced Institutes of Convergence Technology; Suwon 16229 Korea
| | - Sang Eun Kim
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology; Seoul National University; Seoul 08826 Korea
- Department of Nuclear Medicine, Seoul National University College of Medicine; Seoul National University Bundang Hospital; Seongnam 13620 Korea
- Center for Nanomolecular Imaging and Innovative Drug Development; Advanced Institutes of Convergence Technology; Suwon 16229 Korea
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3
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Law MP, Wagner S, Kopka K, Renner C, Pike VW, Schober O, Schäfers M. Preclinical evaluation of an 18F-labelled beta1-adrenoceptor selective radioligand based on ICI 89,406. Nucl Med Biol 2010; 37:517-26. [PMID: 20447564 DOI: 10.1016/j.nucmedbio.2010.01.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 12/21/2009] [Accepted: 01/18/2010] [Indexed: 10/19/2022]
Abstract
PURPOSE Radioligand binding studies indicate a down-regulation of myocardial beta(1)-adrenoceptors (beta(1)-AR) in cardiac disease which may or may not be associated with a decrease in beta(2)-ARs. We have chosen ICI 89,406, a beta(1)-selective AR antagonist, as the lead structure to develop new beta(1)-AR radioligands for PET and have synthesised a fluoro-ethoxy derivative (F-ICI). METHODS (S)-N-[2-[3-(2-Cyano-phenoxy)-2-hydroxy-propylamino]-ethyl]-N'-[4-(2-[(18)F]fluoro-ethoxy)-phenyl]-urea ((S)-[(18)F]F-ICI) was synthesised. Myocardial uptake of radioactivity after intravenous injection of (S)-[(18)F]F-ICI into adult CD(1) mice or Wistar rats was assessed with positron emission tomography (PET) and postmortem dissection. Metabolism was assessed by high-performance liquid chromatography analysis of plasma and urine. RESULTS The heart was visualised with PET after injection of (S)-[(18)F]F-ICI but neither unlabelled F-ICI nor propranolol (non-selective beta-AR antagonist) injected 15 min after (S)-[(18)F]F-ICI affected myocardial radioactivity. Ex vivo dissection demonstrated that predosing with propranolol or CGP 20712 (beta(1)-selective AR-antagonist) did not affect myocardial radioactivity. Radiometabolites rapidly appeared in plasma and both (S)-[(18)F]F-ICI and radiometabolites accumulated in urine. CONCLUSIONS Myocardial uptake of (S)-[(18)F]F-ICI after intravenous injection was mainly at sites unrelated to beta(1)-ARs. (S)-[(18)F]F-ICI is not a suitable beta(1)-selective-AR radioligand for PET.
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Affiliation(s)
- Marilyn P Law
- Department of Nuclear Medicine, University Hospital Münster, D-48149 Münster, Germany.
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4
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Hamdani N, van der Velden J. Lack of specificity of antibodies directed against human beta-adrenergic receptors. Naunyn Schmiedebergs Arch Pharmacol 2009; 379:403-7. [PMID: 19156400 DOI: 10.1007/s00210-009-0392-1] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Accepted: 01/02/2009] [Indexed: 11/25/2022]
Abstract
The present study was designed to investigate if antibodies against beta-adrenergic receptors (betaARs) can be used to determine expression of betaAR in human myocardium. Western blotting was performed to investigate the specificity of antibodies directed against beta(1)AR and beta(2)AR in human left ventricular tissue. A comparison was made between cardiac tissue from patients with idiopathic dilated cardiomyopathy and ischemic heart disease and nonfailing donors. The antibodies directed against beta(1)AR and beta(2)AR recognized several protein bands at different molecular weights. Moreover, both antibodies also recognized multiple proteins in Chinese hamster ovary cells expressing beta(1)AR, beta(2)AR, and even beta(3)AR. betaAR antibodies are not specific and are not suited to study expression of betaAR in human myocardium.
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MESH Headings
- Animals
- Antibodies/immunology
- Antibody Specificity/immunology
- Blotting, Western
- CHO Cells
- Cricetinae
- Cricetulus
- Heart Ventricles/chemistry
- Humans
- Receptors, Adrenergic, beta/analysis
- Receptors, Adrenergic, beta/genetics
- Receptors, Adrenergic, beta/immunology
- Receptors, Adrenergic, beta-1/analysis
- Receptors, Adrenergic, beta-1/genetics
- Receptors, Adrenergic, beta-1/immunology
- Receptors, Adrenergic, beta-2/analysis
- Receptors, Adrenergic, beta-2/genetics
- Receptors, Adrenergic, beta-2/immunology
- Receptors, Adrenergic, beta-3/analysis
- Receptors, Adrenergic, beta-3/genetics
- Receptors, Adrenergic, beta-3/immunology
- Transfection
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Affiliation(s)
- Nazha Hamdani
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands.
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5
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Law MP, Wagner S, Kopka K, Pike VW, Schober O, Schäfers M. Are [O-methyl-11C]derivatives of ICI 89,406 beta1-adrenoceptor selective radioligands suitable for PET? Eur J Nucl Med Mol Imaging 2007; 35:174-85. [PMID: 17906860 DOI: 10.1007/s00259-007-0553-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2007] [Accepted: 07/15/2007] [Indexed: 10/22/2022]
Abstract
PURPOSE Radioligand binding studies show that beta(1)-adrenoceptor (beta(1)-AR) density may be reduced in heart disease without down regulation of beta(2)-ARs. Radioligands are available for measuring total beta-AR density non-invasively with clinical positron emission tomography (PET) but none are selective for beta(1)- or beta(2)-ARs. The aim was to evaluate ICI 89,406, a beta(1)-AR-selective antagonist amenable to labelling with positron emitters, for PET. METHODS The S-enantiomer of an [O-methyl-(11)C] derivative of ICI 89,406 ((S)-[(11)C]ICI-OMe) was synthesised. Tissue radioactivity after i.v. injection of (S)-[(11)C]ICI-OMe (< 2 nmol x kg(-1)) into adult Wistar rats was assessed by small animal PET and post mortem dissection. Metabolism was assessed by HPLC of extracts prepared from plasma and tissues and by measuring [(11)C]CO(2) in exhaled air. RESULTS The heart was visualised by PET after injection of (S)-[(11)C]ICI-OMe but neither unlabelled (S)-ICI-OMe nor propranolol (non-selective beta-AR antagonist) injected 15 min after (S)-[(11)C]ICI-OMe affected myocardial radioactivity. Ex vivo dissection showed that injecting unlabelled (S)-ICI-OMe, propranolol or CGP 20712A (beta(1)-selective AR antagonist) at high dose (> 2 mumol x kg(-1)) before (S)-[(11)C]ICI-OMe had a small effect on myocardial radioactivity. HPLC demonstrated that radioactivity in myocardium was due to unmetabolised (S)-[(11)C]ICI-OMe although (11)C-labelled metabolites rapidly appeared in plasma and liver and [(11)C]CO(2) was detected in exhaled air. CONCLUSION Myocardial uptake of (S)-[(11)C]ICI-OMe after i.v. injection was low, possibly due to rapid metabolism in other tissues. Injection of unlabelled ligand or beta-AR antagonists had little effect indicating that binding was mainly to non-specific myocardial sites, thus precluding the use of (S)-[(11)C]ICI-OMe to assess beta(1)-ARs with PET.
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Affiliation(s)
- Marilyn P Law
- Department of Nuclear Medicine, University Hospital Münster, Albert-Schweitzer-Str. 33, 48149, Münster, Germany.
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6
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Milting H, Scholz C, Arusoglu L, Freitag M, Cebulla R, Jaquet K, Körfer R, V Lewinski D, Kassner A, Brodde OE, Kögler H, El Banayosy A, Pieske B. Selective upregulation of β1-adrenergic receptors and dephosphorylation of troponin I in end-stage heart failure patients supported by ventricular assist devices. J Mol Cell Cardiol 2006; 41:441-50. [PMID: 16765375 DOI: 10.1016/j.yjmcc.2006.04.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2005] [Revised: 03/27/2006] [Accepted: 04/11/2006] [Indexed: 10/24/2022]
Abstract
In terminal failing hearts, adrenergic receptors are downregulated and intracellular adrenergic signal transduction is inhibited. Mechanical circulatory support by ventricular assist devices (VAD) is used to bridge patients to heart transplantation. Mechanical unloading by VAD may induce reverse remodeling in heart transplantation (HTx) candidates. However, little is known on beta-adrenergic receptor subtype regulation and adrenergic signal transduction under VAD-support. We investigated paired myocardial samples from 16 VAD-supported patients and 9 non-failing donor hearts. We analyzed beta-adrenergic receptor subtype regulation by real-time PCR and radioligand binding and cardiac troponin I phosphorylation (by phospho-cTnI-specific antibodies). We found that the beta1-adrenergic receptor (beta1AR) is downregulated at VAD-implantation on mRNA and protein levels whereas the beta2-adrenergic receptor (beta2AR) was not. After VAD-support, beta1AR protein but not its mRNA was upregulated, whereas the degree of cTnI-phosphorylation was reduced. Upregulation of beta1AR was enhanced by beta blocking medication during VAD-support. However, in 9 out of 15 patients, beta1AR-density remained below the 0.25 percentile of donor hearts. VAD-support is associated with partial normalization of the betaAR-signal transduction pathways. This beneficial effect is related to a posttranscriptional increase in beta1AR-density.
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Affiliation(s)
- Hendrik Milting
- Ruhr-Universität Bochum; Herz- and Diabeteszentrum NRW, Erich and Hanna Klessmann-Institut für Kardiovaskuläre Forschung and Entwicklung; 32545 Bad Oeynhausen, Germany.
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7
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Fajardo G, Zhao M, Powers J, Bernstein D. Differential cardiotoxic/cardioprotective effects of beta-adrenergic receptor subtypes in myocytes and fibroblasts in doxorubicin cardiomyopathy. J Mol Cell Cardiol 2006; 40:375-83. [PMID: 16458323 PMCID: PMC3140223 DOI: 10.1016/j.yjmcc.2005.12.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Revised: 11/23/2005] [Accepted: 12/12/2005] [Indexed: 12/20/2022]
Abstract
beta-Adrenoceptor (beta-AR) subtypes act through different signaling pathways to regulate cardiac function and remodeling. Previous in vivo data show a markedly enhanced cardiotoxic response to doxorubicin in beta2-/- mice, which is rescued by the additional deletion of the beta1-AR. We determined whether this differential response was myocyte specific by examining the effects of doxorubicin in myocytes and fibroblasts from WT and beta1, beta2 and beta1/beta2-/- mice. Cells were exposed to doxorubicin at 1-50 microM and viability and apoptosis assessed at 6, 24 and 48 h. WT myocytes showed a time and dose-dependent decrease in viability (42% decrease at 1 microM after 24 h). beta2-/- Myocytes showed a greater decrease in viability vs. WT (20.8% less at 6 h; 14% less at 24 h, P<0.05); beta1-/- and beta1/beta2-/- myocytes showed enhanced survival (beta1-/- 11%; beta1/beta2-/- 18% greater than WT, P<0.05). TUNEL staining demonstrated a similar differential susceptibility (WT 26% apoptotic nuclei, beta2-/- 45.9%, beta1/beta2-/- 16.8%, P<0.05). beta2-/- Fibroblasts also showed enhanced toxicity. Pertussis toxin pretreatment of WT cells decreased survival similar to the beta2-/-, suggesting a role for Gi signaling. JNK was differentially activated in beta2-/- myocytes after doxorubicin and its inhibition increased cardiotoxicity. In conclusion, the differential cardioprotective/cardiotoxic effects mediated by beta1 vs. beta2-AR subtypes in knockout mice are recapitulated in myocytes isolated from these mice. beta2-ARs appear to play a cardioprotective role, whereas beta1-ARs a cardiotoxic role.
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MESH Headings
- Animals
- Cardiomyopathies/chemically induced
- Cardiotonic Agents/pharmacology
- Cell Survival/drug effects
- Cells, Cultured
- Culture Media, Conditioned/pharmacology
- Dose-Response Relationship, Drug
- Doxorubicin/toxicity
- Fibroblasts/drug effects
- Fibroblasts/physiology
- Kinetics
- Mice
- Mice, Congenic
- Mice, Inbred C57BL
- Mice, Inbred DBA
- Mice, Inbred Strains
- Mice, Knockout
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/physiology
- Receptors, Adrenergic, beta-1/genetics
- Receptors, Adrenergic, beta-1/metabolism
- Receptors, Adrenergic, beta-2/genetics
- Receptors, Adrenergic, beta-2/metabolism
- Time Factors
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Affiliation(s)
- Giovanni Fajardo
- Department of Pediatrics, Stanford University, Stanford, CA 94305, USA
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8
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Suzuki G, Mishima T, Tanhehco EJ, Sharov VG, Todor A, Rostogi S, Gupta RC, Chaudhry PA, Anagnostopoulos PV, Nass O, Goldstein S, Sabbah HN. Effects of the AT1-receptor antagonist eprosartan on the progression of left ventricular dysfunction in dogs with heart failure. Br J Pharmacol 2003; 138:301-9. [PMID: 12540520 PMCID: PMC1573662 DOI: 10.1038/sj.bjp.0705032] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
1. We examined the effects of eprosartan, an AT(1) receptor antagonist, on the progression of left ventricular (LV) dysfunction and remodelling in dogs with heart failure (HF) produced by intracoronary microembolizations (LV ejection fraction, EF 30 to 40%). 2. Dogs were randomized to 3 months of oral therapy with low-dose eprosartan (600 mg once daily, n=8), high-dose eprosartan (1200 mg once daily, n=8), or placebo (n=8). 3. In the placebo group, LV end-diastolic (EDV) and end-systolic (ESV) volumes increased after 3 months (68+/-7 vs 82+/-9 ml, P<0.004, 43+/-1 vs 58+/-7 ml, P<0.003, respectively), and EF decreased (37+/-1 vs 29+/-1%, P<0.001). In dogs treated with low-dose eprosartan, EF, EDV, and ESV remained unchanged over the course of therapy, whereas in dogs treated with high-dose eprosartan, EF increased (38+/-1 vs 42+/-1%, P<0.004) and ESV decreased (41+/-1 vs 37+/-1 ml, P<0.006), Eprosartan also decreased interstitial fibrosis and cardiomyocyte hypertrophy. 4. We conclude that eprosartan prevents progressive LV dysfunction and attenuates progressive LV remodelling in dogs with moderate HF and may be useful in treating patients with chronic HF.
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Affiliation(s)
- George Suzuki
- Department of Medicine, Division of Cardiovascular Medicine, Henry Ford Heart & Vascular Institute, Detroit, Michigan, U.S.A
| | - Takayuki Mishima
- Department of Medicine, Division of Cardiovascular Medicine, Henry Ford Heart & Vascular Institute, Detroit, Michigan, U.S.A
| | - Elaine J Tanhehco
- Department of Medicine, Division of Cardiovascular Medicine, Henry Ford Heart & Vascular Institute, Detroit, Michigan, U.S.A
| | - Victor G Sharov
- Department of Medicine, Division of Cardiovascular Medicine, Henry Ford Heart & Vascular Institute, Detroit, Michigan, U.S.A
| | - Anastassia Todor
- Department of Medicine, Division of Cardiovascular Medicine, Henry Ford Heart & Vascular Institute, Detroit, Michigan, U.S.A
| | - Sharad Rostogi
- Department of Medicine, Division of Cardiovascular Medicine, Henry Ford Heart & Vascular Institute, Detroit, Michigan, U.S.A
| | - Ramesh C Gupta
- Department of Medicine, Division of Cardiovascular Medicine, Henry Ford Heart & Vascular Institute, Detroit, Michigan, U.S.A
| | - Pervaiz A Chaudhry
- Department of Medicine, Division of Cardiovascular Medicine, Henry Ford Heart & Vascular Institute, Detroit, Michigan, U.S.A
| | - Petros V Anagnostopoulos
- Department of Medicine, Division of Cardiovascular Medicine, Henry Ford Heart & Vascular Institute, Detroit, Michigan, U.S.A
| | - Omar Nass
- Department of Medicine, Division of Cardiovascular Medicine, Henry Ford Heart & Vascular Institute, Detroit, Michigan, U.S.A
| | - Sidney Goldstein
- Department of Medicine, Division of Cardiovascular Medicine, Henry Ford Heart & Vascular Institute, Detroit, Michigan, U.S.A
| | - Hani N Sabbah
- Department of Medicine, Division of Cardiovascular Medicine, Henry Ford Heart & Vascular Institute, Detroit, Michigan, U.S.A
- Author for correspondence:
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9
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Wang X, Dhalla NS. Modification of beta-adrenoceptor signal transduction pathway by genetic manipulation and heart failure. Mol Cell Biochem 2000; 214:131-55. [PMID: 11195784 DOI: 10.1023/a:1007131925048] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The beta-adrenoceptor (beta-AR) mediated signal transduction pathway in cardiomyocytes is known to involve beta1- and beta2-ARs, stimulatory (Gs) and inhibitory (Gi) guanine nucleotide binding proteins, adenylyl cyclase (AC) and cAMP-dependent protein kinase (PKA). The activation of beta1- and beta2-ARs has been shown to increase heart function by increasing Ca2+ -movements across the sarcolemmal membrane and sarcoplasmic reticulum through the stimulation of Gs-proteins, activation of AC and PKA enzymes and phosphorylation of the target sites. The activation of PKA has also been reported to increase phosphorylation of some myofibrillar proteins (for promoting cardiac relaxation) and nuclear proteins (for cardiac hypertrophy). The activation of beta2-AR has also been shown to affect Gi-proteins, stimulate mitogen activated protein kinase and increase protein synthesis by enhancing gene expression. Beta1- and beta2-ARs as well as AC are considered to be regulated by PKA- and protein kinase C (PKC)-mediated phosphorylations directly; both PKA and PKC also regulate beta-AR indirectly through the involvement of beta-AR kinase (betaARK), beta-arrestins and Gbeta gamma-protein subunits. Genetic manipulation of different components and regulators of beta-AR signal transduction pathway by employing transgenic and knockout mouse models has provided insight into their functional and regulatory characteristics in cardiomyocytes. The genetic studies have also helped in understanding the pathophysiological role of PARK in heart dysfunction and therapeutic role of betaARK inhibitors in the treatment of heart failure. Varying degrees of defects in the beta-AR signal transduction system have been identified in different types of heart failure to explain the attenuated response of the failing heart to sympathetic stimulation or catecholamine infusion. A decrease in beta1-AR density, an increase in the level of G1-proteins and overexpression of betaARK are usually associated with heart failure; however, these attenuations have been shown to be dependent upon the type and stage of heart failure as well as region of the heart. Both local and circulating renin-angiotensin systems, sympathetic nervous system and endothelial cell function appears to regulate the status of beta-AR signal transduction pathway in the failing heart. Thus different components and regulators of the beta-AR signal transduction pathway appears to represent important targets for the development of therapeutic interventions for the treatment of heart failure.
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Affiliation(s)
- X Wang
- Institute of Cardiovascular Sciences, Department of Physiology, Faculty of Medicine University of Manitoba, Winnipeg, Canada
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10
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Schotten U, Filzmaier K, Borghardt B, Kulka S, Schoendube F, Schumacher C, Hanrath P. Changes of beta-adrenergic signaling in compensated human cardiac hypertrophy depend on the underlying disease. Am J Physiol Heart Circ Physiol 2000; 278:H2076-83. [PMID: 10843907 DOI: 10.1152/ajpheart.2000.278.6.h2076] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In human heart failure, desensitization of the beta-adrenergic signal transduction has been reported to be one of the main pathophysiological alterations. However, data on the beta-adrenergic system in human compensated cardiac hypertrophy are very limited. Therefore, we studied the myocardial beta-adrenergic signaling in patients suffering from hypertrophic obstructive cardiomyopathy (HOCM, n = 9) or from aortic valve stenosis (AoSt, n = 8). beta-Adrenoceptor density determined by [(125)I]iodocyanopindolol binding was reduced in HOCM and AoSt compared with nonhypertrophied, nonfailing myocardium (NF) of seven organ donors. In HOCM the protein expression of stimulatory G protein alpha-subunit (G(s)alpha) measured by immunoblotting was unchanged, whereas the inhibitory G protein alpha-subunit (Galpha(i-2)) was increased. In contrast, in AoSt, Galpha(i-2) protein was unchanged, but G(s)alpha protein was increased. Adenylyl cyclase stimulation by isoproterenol was reduced in HOCM but not in AoSt. Plasma catecholamine levels were normal in all patients. In conclusion, both forms of hypertrophy are associated with beta-adrenoceptor downregulation but with different changes at the G protein level that occur before symptomatic heart failure due to progressive dilatation of the left ventricle develops and are not due to elevated plasma catecholamine levels.
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Affiliation(s)
- U Schotten
- Department of Cardiology, University Hospital Aachen, Germany.
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11
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Tse J, Huang MW, Leone RJ, Weiss HR, He YQ, Scholz PM. Down regulation of myocardial beta1-adrenoceptor signal transduction system in pacing-induced failure in dogs with aortic stenosis-induced left ventricular hypertrophy. Mol Cell Biochem 2000; 205:67-73. [PMID: 10821423 DOI: 10.1023/a:1007085027234] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We recently demonstrated that rapid ventricular pacing caused cardiac failure (Failure) in dogs with aortic stenosis-induced left ventricular hypertrophy (Hypertrophy) and isoproterenol caused no significant increases in function, O2 consumption and intracellular cyclic AMP level in the failing hypertrophied hearts. We tested the hypothesis that alterations in the beta1-adrenoceptor-signal transduction pathway would correlate with the reduced functional and metabolic responses to beta-adrenergic stimulation during the transition from the compensated hypertrophy to failure. Pressure overload-induced left ventricular hypertrophy was created using aortic valve plication in 10 dogs over a 6-month period. Five months after aortic valve plication, congestive heart failure was induced in 5 dogs by rapid ventricular pacing at 240 bpm for 4 weeks. The density of myocardial beta1-adrenoceptors (fmoles/mg membrane protein; fmoles/g wet tissue) was significantly reduced in the Failure dogs (176+/-19; 755+/-136) when compared to those of the Control (344+/-51; 1,551+/-203) and the Hypertrophy (298+/-33; 1,721+/-162) dogs. The receptor affinities were not significantly different among all groups. There was a small but significant decrease in the percentage of beta1-adrenoceptors of the failing hypertrophied hearts (62+/-3%) when compared to that of the hypertrophied hearts (77+/-5%). The basal myocardial adenylyl cyclase activity (pmoles/mg protein/min) was significantly lower in the Failure dogs (45+/-4) than in the Control (116+/-14) and Hypertrophy (86+/-6) dogs. The forskolin (0.1 mM)-stimulated adenylyl cyclase activity was also significantly lower in the Failure dogs (158+/-17) than in the Control dogs (296+/-35) and slightly lower than in the Hypertrophy dogs (215+/-10). There were no significant differences in low Km cyclic AMP-phosphodiesterase activities among all groups. We conclude that down regulation of beta1-adrenoceptors and reduced adenylyl cyclase activities contribute to the decreases in myocardial functions and beta-adrenergic responses in the failing hypertrophied hearts induced by rapid ventricular pacing.
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Affiliation(s)
- J Tse
- Department of Anesthesia, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, New Brunswick 08901-1977, USA
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12
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Broadley KJ. Review of mechanisms involved in the apparent differential desensitization of beta1- and beta2-adrenoceptor-mediated functional responses. JOURNAL OF AUTONOMIC PHARMACOLOGY 1999; 19:335-45. [PMID: 10961739 DOI: 10.1111/j.1365-2680.1999.tb00006.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
1. There has been considerable debate whether responses mediated via beta1- and beta2-adrenoceptors (beta1ARs and beta2ARs) display the same degree of desensitization after prolonged or repeated exposure to agonists. 2. Examples are provided for selective desensitization of functional responses and loss of binding sites for beta1ARs. Equally, examples are given of selective desensitization and down-regulation involving beta2ARs. 3. This review examines whether receptor subtype-selective desensitization of betaAR-mediated responses can occur and whether even within the same subtype, there may be tissue-selective desensitization. Possible reasons why apparent selectivity of desensitization of functional responses may occur are considered and are divided into methodological and non-methodological factors. 4. Methodological factors discussed are: the concentration of agonist used for inducing desensitization and the washout times before construction of the post-incubation concentration-response curve (CRC), the need for correction of CRCs from time-matched controls, and the methods adopted for plotting CRCs. 5. Four non-methodological factors are considered. Firstly, the roles of different receptor reserves for the responses of each tissue can have an important effect on whether desensitization is apparent; a large reserve will make desensitization less likely to be apparent. Secondly, there is more than one site at which desensitization occurs; receptors are uncoupled from adenylyl cyclase activation, there is an additional site at the level of stimulation of cyclic AMP-dependent protein kinase and betaARs may ultimately be down-regulated. These processes may differ depending on the tissue and conditions and this may influence whether differential desensitization occurs between tissues. Thirdly, the apparent degree of desensitization after washout of an agonist can depend upon the rate of resensitization. Experiments to overcome this problem are described which demonstrate betaAR desensitization in the continued presence of agonist. Finally, the role of up-regulation of PDE in desensitization is discussed.
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Affiliation(s)
- K J Broadley
- Division of Pharmacology, Welsh School of Pharmacy, Cardiff University, Cathays Park, UK
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13
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Martin SW, Broadley KJ. Relative resistance of functional β2-adrenoceptor-mediated smooth muscle responses to in vitro desensitization. Can J Physiol Pharmacol 1999. [DOI: 10.1139/y99-003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effects of in vitro incubation of rat isolated left atria, pulmonary artery rings, and aortic rings with isoprenaline (10-6 M for 6 h) were examined to compare the degree of desensitization of β1- and β2-adrenoceptor-mediated functional responses. The experimental protocols were carefully controlled to exclude influence from persistence of agonist in the tissues after the prolonged exposures, time-dependent changes in tissue sensitivity, and the methods of plotting the data. Concentration-response curves for isoprenaline were constructed before incubation with isoprenaline and, after washout during 1 h, a second curve was obtained. Two protocols were employed: firstly, the preincubation curve was constructed to ensure that a maximum response was obtained (>10-6 M) and, secondly, the preincubation curve was constructed to a maximum isoprenaline concentration of 10-6 M. Preincubation curves were corrected for time-dependent changes in sensitivity from sham-incubation control experiments. There was significant desensitization of the β1-adrenoceptor-mediated positive inotropic responses of the left atria, using both protocols, seen as rightward shifts (dose ratios: 4.48 ± 1.12 and 8.39 ± 2.3) of the concentration-response curves and depression of the maximum responses (77.0 ± 3.2 and 60.8 ± 5.5%). In contrast, the β2-adrenoceptor-mediated relaxations of the noradrenaline-constricted pulmonary artery and aorta did not display a significant loss of sensitivity. When the relaxation responses were plotted as a percentage of the noradrenaline-induced tone, there was no significant rightward shift of the concentration-response curves in the pulmonary artery (dose ratios: 2.82 ± 1.33 and 2.24 ± 0.62) or aorta (dose ratios: 1.43 ± 0.62 and 1.31 ± 0.27) and thus no desensitization.Key words: rat atria, pulmonary artery, aorta, β-adrenoceptors, desensitization.
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Gu XH, Kompa AR, Summers RJ. Regulation of beta-adrenoceptors in a rat model of cardiac failure: effect of perindopril. J Cardiovasc Pharmacol 1998; 32:66-74. [PMID: 9676723 DOI: 10.1097/00005344-199807000-00011] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This study investigated the effects of myocardial infarction (MI)-induced cardiac failure and treatment with an angiotensin-converting enzyme (ACE) inhibitor perindopril (2 mg/kg/day) on rat beta-adrenoceptor (beta-ar) subtypes in anatomically defined regions of infarcted left ventricular (LV) free wall and noninfarcted tissue from right ventricle (RV) by using autoradiography. After 5 weeks of MI, rats with large MI size (>42%) had developed cardiac failure and beta1-ars were significantly decreased (-59%; p < 0.01) in the border region of the infarcted LV and almost abolished in the infarcted area (-90%; p < 0.005) compared with normal LV from sham-operated controls. The beta-ar changes were not found in the noninfarcted area of the same LV or in RV. MI did not significantly alter the number of beta2-ar subtypes in any region of the ventricles. Perindopril treatment for 4 weeks reduced mean cardiac region weights but did not affect beta-ar density in any cardiac region in either sham-operated or MI rats. These results indicate that cardiac failure due to MI causes significant downregulation of beta1-ars only in border and infarcted regions of rat LV and no change in beta2-ar in any area. It also suggests that the improved response of the infarcted rat heart to isoprenaline stimulation after ACE inhibitors does not result from changes in the numbers of cardiac beta-ars.
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Affiliation(s)
- X H Gu
- Department of Pharmacology, University of Melbourne, Parkville, Victoria, Australia
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Ouedraogo L, Magnon M, Sawadogo L, Tricoche R. Receptors involved in the positive inotropic action induced by dopamine on the ventricle of a 7-day-old chick embryo heart. Fundam Clin Pharmacol 1998; 12:133-42. [PMID: 9565766 DOI: 10.1111/j.1472-8206.1998.tb00933.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Earlier experiments only revealed involvement of sympathetic pre-synaptic dopaminergic receptors in dopamine induced inotropism in myocardium. We therefore used electrically stimulated (1 Hz) isolated 7-day-old chick embryo heart ventricles, thought to be devoid of functional sympathetic nerves, to re-investigate post-synaptic receptors involvement and particularly that of dopaminergic receptors in the positive inotropic effect of dopamine. The results showed that noradrenaline, isoprenaline and dopamine produced a positive inotropic effect with a similar efficacy and with an order of potency as follows: Isoprenaline = Noradrenaline > Dopamine. Tyramine induced no significant modification of the "initial tension" indicating that functional sympathetic innervation and/or releasable endogenous catecholamines were not demonstrable in the 7-day-old chick embryo heart ventricle. Propranolol (1 microM) competitively antagonized the positive inotropic response to isoprenaline, noradrenaline and dopamine, meanwhile phentolamine (3 microM) failed to significantly modify the effects of both noradrenaline and dopamine, indicating that these catecholamines induced their positive inotropic effects via stimulation of beta-adrenoceptors; involvement of alpha-adrenergic receptors stimulation was not demonstrable in these effects. Moreover, haloperidol (2 microM) antagonized the positive inotropic response to dopamine but had not any significant effect on the response to isoprenaline. The combined application of both propranolol and haloperidol antagonized the positive inotropic response to dopamine to a greater extent than when these two antagonists were given alone. Consequently, post-synaptic dopaminergic receptors were also involved in the positive inotropic effect of dopamine. Furthermore, in preparations in which sodium channels were inactivated by high potassium physiological salt solution, high concentrations of dopamine (0.1 mM to 1 mM) induced a slow developing electrical and positive inotropic responses which were also inhibited by propranolol and haloperidol, but not by phentolamine. These latter results indicated that like beta-adrenergic stimulation, the slow inward calcium current activated by stimulation of adenylate cyclase, was at least in part involved in the positive inotropic response to dopamine. In conclusion, dopamine induced its positive inotropism via stimulation of post-synaptic beta-adrenergic and dopaminergic receptors. The contribution of dopaminergic receptors in this positive inotropic effect might be of the DA-2 receptors since haloperidol used had been reported to be more DA-2 than DA-1 antagonist. These DA-2 receptors subtypes would mediate activation of adenylate cyclase.
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Affiliation(s)
- L Ouedraogo
- Département de Biologie et Physiologie Animales, Faculté des Sciences et Techniques (FAST) Université de Ouagadougou, Burkina Faso
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Brodde OE, Vogelsang M, Broede A, Michel-Reher M, Beisenbusch-Schäfer E, Hakim K, Zerkowski HR. Diminished responsiveness of Gs-coupled receptors in severely failing human hearts: no difference in dilated versus ischemic cardiomyopathy. J Cardiovasc Pharmacol 1998; 31:585-94. [PMID: 9554809 DOI: 10.1097/00005344-199804000-00018] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In end-stage heart failure, cardiac beta-adrenoceptors are decreased and cardiac Gi protein is increased. We assessed beta-adrenoceptors, G proteins, and effects of several beta-adrenoceptor agonists, histamine, and 5-HT on adenylyl cyclase activity in right and left atria and left ventricles and on left ventricular contractility in six potential heart transplant donors (nonfailing hearts; NFHs) and in nine patients with end-stage dilated cardiomyopathy (DCM) and 11 patients with end-stage ischemic cardiomyopathy (ICM) to establish whether the functional responsiveness of all cardiac Gs-coupled receptors is reduced. Beta-adrenoceptors were reduced in all three tissues; in DCM, beta1-adrenoceptors were more markedly downregulated; in ICM, both beta1- and beta2-adrenoceptors were diminished. In all three tissues, isoprenaline-, terbutaline-, histamine- and 5-HT-induced adenylyl cyclase activation was reduced similarly in DCM and ICM. Moreover, in DCM and ICM, guanosine triphosphate (GTP)- (involving Gs and Gi) activated adenylyl cyclase was significantly diminished, whereas NaF-activated (involving only Gs) and Mn2+-activated (acting at the catalytic unit of the enzyme) adenylyl cyclase was unaltered. Left ventricular positive inotropic responses to beta1- (noradrenaline, dopamine, and dobutamine), beta2- (terbutaline), and beta1- and beta2-adrenoceptors (isoprenaline, adrenaline, and epinine), as well as H2-receptor (histamine) stimulation were significantly reduced. The extent of reduction was not different for each agonist in ICM and DCM. We conclude that in DCM and ICM, functional responsiveness of all cardiac Gs-coupled receptors is similarly reduced.
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Affiliation(s)
- O E Brodde
- Department of Internal Medicine, University of Essen, Germany
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17
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Smiley RM, Kwatra MM, Schwinn DA. New developments in cardiovascular adrenergic receptor pharmacology: molecular mechanisms and clinical relevance. J Cardiothorac Vasc Anesth 1998; 12:80-95. [PMID: 9509364 DOI: 10.1016/s1053-0770(98)90062-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- R M Smiley
- Department of Anesthesiology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
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Flesch M, Erdmann E, Böhm M. Changes in beta-adrenoceptors and G-proteins during the transition from cardiac hypertrophy to heart failure. J Card Fail 1996; 2:S35-43. [PMID: 8951559 DOI: 10.1016/s1071-9164(96)80057-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- M Flesch
- Klinik III für Innere Medizin, Universität zu Köln, Germany
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19
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André C, Erraji L, Gaston J, Grimber G, Briand P, Guillet JG. Transgenic mice carrying the human beta 2-adrenergic receptor gene with its own promoter overexpress beta 2-adrenergic receptors in liver. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 241:417-24. [PMID: 8917438 DOI: 10.1111/j.1432-1033.1996.00417.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Up to now, transgenic mice models created to study the physiological impact of alterations in the human beta-adrenoceptor system have only focused on cardiac tissues and carried hybrid transgenes with strong cardiac promoters. We have developed a transgenic mouse strain (F28) carrying the human beta 2-adrenoceptor gene with its natural promoter region with the aim of producing a model that more closely reproduces the natural human beta 2-adrenoceptor tissue expression pattern. By means of northern blot analyses, using the appropriate probes, we have obtained evidence that (a) the human beta 2-adrenoceptor's structural gene is transcribed in several tissues of F28 mice; (b) the tissue distribution pattern of human beta 2-adrenoceptor mRNA in F28 mice completely differs from that of mouse beta 2-adrenoceptor mRNA; and (c) the tissue distribution pattern of mouse beta 2-adrenoceptor mRNA in F28 mice is very similar to that observed in their non-transgenic littermates. Like humans, F28 mice express human beta 2-adrenoceptor mRNA in liver, lung, brain, heart, and muscle. However, unlike humans, F28 mice do not accumulate human beta 2-adrenoceptor mRNA in kidney and spleen. By using [125I]iodocyanopindolol to label all beta-adrenoceptors and ICI 118,551 to discriminate between the binding to beta 2- and beta 1-adrenoceptors we have demonstrated that the beta 2-adrenoceptor binding activity increases over control values in F28 mouse tissues that accumulate transgenic mRNA. Accordingly, the number of beta 2-adrenoceptors increased slightly over the control values in muscle, heart, brain, and lung of F28 mice, while in liver these receptors were strongly overexpressed. We further showed that transgene beta 2-adrenoceptors couple to GTP-binding proteins, mediate beta-adrenoceptor agonist-stimulated adenylyl cyclase activation, and cause a strong enhancement of this response in liver membranes of F28 versus control mice. Finally, F28 mice show a phenotype of depressed ponderal development and perturbed hindquarter movements. This unique model should be useful to further investigate beta 2-adrenoceptor causal relationships with human pathologies.
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MESH Headings
- Adenylyl Cyclases/metabolism
- Animals
- Base Sequence
- DNA Probes/genetics
- Female
- GTP-Binding Proteins/metabolism
- Gene Expression
- Humans
- Iodocyanopindolol
- Isoproterenol/metabolism
- Liver/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Inbred DBA
- Mice, Transgenic
- Phenotype
- Pindolol/analogs & derivatives
- Pindolol/metabolism
- Promoter Regions, Genetic
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Adrenergic, beta-1/metabolism
- Receptors, Adrenergic, beta-2/genetics
- Receptors, Adrenergic, beta-2/metabolism
- Tissue Distribution
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Affiliation(s)
- C André
- INSERM U380, Institut Cochin de Génétique Moléculaire, Université René Descartes, Paris, France
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Yamada S, Ohkura T, Uchida S, Inabe K, Iwatani Y, Kimura R, Hoshino T, Kaburagi T. A sustained increase in beta-adrenoceptors during long-term therapy with metoprolol and bisoprolol in patients with heart failure from idiopathic dilated cardiomyopathy. Life Sci 1996; 58:1737-44. [PMID: 8637398 DOI: 10.1016/0024-3205(96)00155-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Effects of long-term therapy with beta 1-selective antagonists (metoprolol, bisoprolol) on beta-adrenoceptors in lymphocytes of patients with idiopathic dilated cardiomyopathy (DCM) were examined. There was a significant reduction in the number of lymphocyte beta-adrenoceptors in patients with DCM compared to that in healthy volunteers, as demonstrated by a selective decrease in maximum number of binding sites (Bmax) for (-)-[125I]iodocyanopindolol (CYP). A therapy with metoprolol and bisoprolol in these patients caused a marked increase in lymphocyte beta-adrenoceptor density. The significant increase was observed from 2 or 3 months after the start of therapy with these drugs, and it was maintained during the therapy for 24 months. The left ventricular ejection fraction in patients with DCM was improved by the long-term therapy with metoprolol and bisoprolol, and this effect seems to be correlated with an observed enhancement of lymphocyte beta-adrenoceptors in the time course. Also, the increase in lymphocyte beta-adrenoceptors appears to be correlated with a gradual amelioration in circulating catecholamine levels by the long-term therapy with beta-adrenoceptor antagonists in patients with DCM. Thus, the present study suggests that beta-adrenoceptors in lymphocytes of patients with DCM are up-regulated by a long-term therapy with metoprolol and bisoprolol.
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Affiliation(s)
- S Yamada
- Department of Biopharmacy, School of Pharmaceutical Sciences, University of Shizuoka, Japan
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21
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Brändle M, Wang W, Zucker IH. Hemodynamic correlates of baroreflex impairment of heart rate in experimental canine heart failure. Basic Res Cardiol 1996; 91:147-54. [PMID: 8740531 DOI: 10.1007/bf00799687] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The arterial baroreflex has been shown to be depressed in both clinical and experimental heart failure. The mechanism and significance of this depression remains controversial. Part of the change may reside in the baroreceptor as well as in the target organ. Previous studies in this laboratory have shown that there is no central depression of the baroreflex in anesthetized dogs. The present study was undertaken to determine the relationship between the change in baroreflex sensitivity (BRS) and the impairment of various hemodynamic parameters during the development of chronic heart failure in conscious dogs (n = 15). The animals were instrumented to record pressures and derivatives in the left atrium, aorta and the left ventricle. Heart failure was achieved by rapid left ventricular pacing (250 bpm) until the development of clinical signs. BRS was determined by correlating systolic arterial blood pressure and pulse interval during bolus injections of nitroglycerin and phenylephrine. Data were analyzed by correlating the changes in BRS (n = 90) with respect to changes in each parameter. No or a weak correlation was found between the changes in the baroreflex and parameters of systolic function or time of pacing. A stronger correlation was found between BRS and parameters of preload such as left ventricular enddiastolic pressure and left atrial pressure (p < 0.001). In general, the bradycardia responses were depressed less than the tachycardia responses. The correlation between BRS and left atrial or left ventricular end diastolic pressure is consistent with the view that augmented input from cardiac receptors may contribute to the depressed baroreflex function in heart failure. These data also suggest that the sympathetic limb of baroreflex control of heart rate in chronic heart failure is depressed earlier and to a greater extent then the vagal limb.
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Affiliation(s)
- M Brändle
- Department of Physiology and Biophysics, University of Nebraska College of Medicine, Omaha 68198-4575, USA
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Eschenhagen T, Mende U, Diederich M, Hertle B, Memmesheimer C, Pohl A, Schmitz W, Scholz H, Steinfath M, Böhm M, Michel MC, Brodde OE, Raap A. Chronic treatment with carbachol sensitizes the myocardium to cAMP-induced arrhythmia. Circulation 1996; 93:763-71. [PMID: 8641006 DOI: 10.1161/01.cir.93.4.763] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND The present study investigated biochemical and functional consequences of chronic activation of the inhibitory Gi alpha-coupled adenylyl cyclase pathway in the heart. METHODS AND RESULTS Rats (220 to 260 g) were treated with 4-day infusions of the M-cholinoceptor agonist carbachol (9.6 mg/kg per day) or vehicle. An additional group that received the beta-adrenoceptor agonist isoprenaline (2.4 mg/kg per day) served as control. The main finding was that chronic infusion of carbachol led to a marked increase in isoprenaline- or forskolin-induced arrhythmia in electrically driven papillary muscles (in vitro). Compared with control, the potency of isoprenaline and forskolin to induce arrhythmia in cardiac preparations from carbachol-treated rats was increased 36- and 2.2-fold and the efficacy was increased 7.3- and 2.3-fold, respectively. The potency of carbachol to antagonize the isoprenaline- and forskolin-induced arrhythmia was decreased 30-fold. These changes were accompanied by a decrease in left ventricular M-cholinoceptor density by 15% (P < .05) and a decrease in pertussis toxin-sensitive G proteins (Gi alpha) by 26% (P < .05) without a decrease in the corresponding mRNAs. beta-Adrenoceptor density and basal and stimulated adenylyl cyclase activity remained unchanged. In contrast, isoprenaline infusion induced a decrease in arrhythmogenic potency of forskolin (P = NS), which was accompanied by a decrease in beta-adrenoceptor density, an increase in Gi alpha protein and mRNA levels, and a decrease in basal and stimulated adenylyl cyclase activity. CONCLUSIONS Chronic parasympathetic activation sensitizes the myocardium to cAMP-induced arrhythmia. These changes may be due to quantitative alterations in functional Gi alpha.
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Affiliation(s)
- T Eschenhagen
- Abteilung Allgemeine Pharmakologie, Universitäts-Krankenhaus Eppendorf, Hamburg, Germany
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Engelhardt S, Böhm M, Erdmann E, Lohse MJ. Analysis of beta-adrenergic receptor mRNA levels in human ventricular biopsy specimens by quantitative polymerase chain reactions: progressive reduction of beta 1-adrenergic receptor mRNA in heart failure. J Am Coll Cardiol 1996; 27:146-54. [PMID: 8522688 DOI: 10.1016/0735-1097(95)00425-4] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVES This study investigated the relation between the severity of heart failure and the extent of the reduction of beta 1-adrenergic receptor messenger ribonucleic acid (mRNA) levels in biopsy specimens from the ventricular septum obtained during cardiac catheterization of patients with various degrees of heart failure. BACKGROUND Heart failure is accompanied by desensitization of the beta-adrenergic receptor system, which is in part due to downregulation of beta 1-adrenergic receptors. Downregulation of beta 1-adrenergic receptors has been suggested to be caused by reductions in mRNA levels. METHODS Because biopsy specimens were small and receptor mRNAs not abundant, mRNA levels were determined by quantitative reverse transcription/polymerase chain reactions. This method was validated by measuring synthetic ribonucleic acid (RNA) standards and samples from explanted hearts by solution hybridization assays. Both methods yielded similar results, but the polymerase chain reaction method was approximately 1,000-fold more sensitive. Sources of variations in the polymerase chain reaction were quantitated and found to be best controlled for by determination of the glyceraldehyde phosphate dehydrogenase mRNA as an endogenous control. RESULTS Beta 1-adrenergic receptor mRNA levels in the biopsy specimens were decreased by 7% in mild (New York Heart Association functional class II), 26% in moderate (functional class III) and > 50% in severe heart failure (functional class IV). There was a good correlation between hemodynamic indicators of heart failure and beta 1-adrenergic receptor mRNA levels. In contrast, beta 2-adrenergic receptor mRNA levels were apparently unaffected by heart failure. CONCLUSIONS Reduced beta 1-adrenergic receptor mRNA levels occur early in heart failure and can be detected in septal biopsy specimens during right heart catheterization. The reduction in beta 1-adrenergic receptor expression may contribute to further loss of cardiac function.
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Affiliation(s)
- S Engelhardt
- Laboratorium für Molekulare Biologie, Universität München, Germany
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Abstract
In the human heart the beta-adrenergic receptor-G-protein-adenylyl cyclase system is the most powerful physiologic mechanism to acutely increase contractility and/or heart rate. In the failing human myocardium beta 1-adrenergic receptor number is decreased, and this is accompanied by a reduced beta 1-adrenergic receptor mediated positive inotropic effect. Cardiac beta 2-adrenergic receptor number may or may not decrease; however, beta 2- adrenergic receptor mediated positive inotropic effects are also reduced, possibly because the functional activity of myocardial Gi is increased, thereby inhibiting cyclic AMP formation. The aging human heart shows some similarities with the failing human heart: in both settings, of chronic heart failure and age, beta-adrenergic receptor mediated effects and all other cyclic AMP dependent effects are depressed and Gi-protein is increased.
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Affiliation(s)
- O E Brodde
- Institute of Pharmacology University of Halle-Wittenberg, Halle (Saale) Germany
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25
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Sympathetic Neuroeffector Mechanisms in the Failing and Hypertrophied Myocardium. DEVELOPMENTS IN CARDIOVASCULAR MEDICINE 1995. [DOI: 10.1007/978-1-4613-1237-6_30] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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26
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Alterations of ?-adrenoceptor-G-protein-regulated adenylyl cyclase in heart failure. Mol Cell Biochem 1995. [DOI: 10.1007/bf00944795] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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27
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Martin SW, Broadley KJ. Effects of chronic intravenous infusions of dopexamine and isoprenaline to rats on D1-, beta 1- and beta 2-receptor-mediated responses. Br J Pharmacol 1994; 112:595-603. [PMID: 7915614 PMCID: PMC1910351 DOI: 10.1111/j.1476-5381.1994.tb13116.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
1. Rats received intravenous infusions of dopexamine, an agonist with selectivity for D1-dopamine receptors and beta 2-adrenoceptors (240 micrograms kg-1 h-1), isoprenaline, a beta 1- and beta 2-adrenoceptor agonist (40 micrograms kg-1 h-1) or vehicle (isotonic saline at pH 2.5) for 7 days via subcutaneously implanted osmotic minipumps. Tissues were then removed for determination of functional responsiveness to beta 1-adrenoceptor, beta 2-adrenoceptor and dopamine D1-receptor stimulation. 2. The beta 1-adrenoceptor-mediated responses of the spontaneously beating right atrium (increase in rate) and paced left atrium (increase in tension) showed significant reductions in sensitivity to isoprenaline following isoprenaline infusion. The EC50 values were significantly increased from 5.6 to 17.7 nM in right atria and from 7.4 to 27.1 nM in left atria. The maximum rate increase of right atria was also significantly less after isoprenaline infusion compared with controls (164.0 and 251.9 beats min-1, respectively) but the maximum tension responses of left atria were not significantly different. After infusion with dopexamine, however, there was no change in sensitivity of the left or right atria to beta 1-adrenoceptor stimulation by isoprenaline. 3. beta 2-Adrenoceptor-mediated relaxation responses to isoprenaline of the pulmonary artery, constricted with noradrenaline (6 x 10(-8) M), showed no significant difference in maximum response or EC50 in tissue from isoprenaline- or dopexamine-infused rats compared with vehicle-infused controls. beta 2-Adrenoceptor-mediated vasodilator responses were also examined in the kidney perfused with the thromboxane A2 analogue, U46619 (7.1 x 10(-8) M) to raise perfusion pressure. As with the pulmonary artery, there was no significant difference in ED50 or maximum response to isoprenaline in kidneys from isoprenaline infused animals compared with vehicle controls.4. The DI-receptor-mediated vasodilator responses to dopamine of the kidney perfused with U46619were reduced after infusion of rats with dopexamine. The maximum fall in perfusion pressure(16.0 mmHg) and ED50 value (5.2 microg) were significantly different from those after vehicle infusion(31.5 mmHg; 1.5 microg).5. These results show that functional responses mediated via beta1-adrenoceptors and DI-receptors are reduced by intravenous infusions of isoprenaline and dopexamine, respectively. In contrast, the beta2-adrenoceptor-mediated vasodilator responses of the pulmonary artery and kidney are not reduced by these agonists. Thus, under identical conditions, there appears to be selective down-regulation of peripheral beta 1- and D,-receptors, but not of beta 2-adrenoceptors.
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MESH Headings
- 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid
- Adrenergic beta-Agonists/administration & dosage
- Adrenergic beta-Agonists/pharmacology
- Animals
- Dopamine/administration & dosage
- Dopamine/analogs & derivatives
- Dopamine/pharmacology
- Down-Regulation/drug effects
- Drug Implants
- Heart Atria/drug effects
- In Vitro Techniques
- Infusions, Intravenous
- Isoproterenol/administration & dosage
- Isoproterenol/pharmacology
- Male
- Myocardial Contraction/drug effects
- Prostaglandin Endoperoxides, Synthetic/pharmacology
- Pulmonary Artery/drug effects
- Rats
- Rats, Wistar
- Receptors, Adrenergic, beta-1/drug effects
- Receptors, Adrenergic, beta-2/drug effects
- Receptors, Dopamine D1/drug effects
- Renal Circulation/drug effects
- Thromboxane A2/analogs & derivatives
- Thromboxane A2/pharmacology
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Affiliation(s)
- S W Martin
- Department of Pharmacology, Welsh School of Pharmacy, University of Wales, Cardiff
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28
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Turrin MQ, Ferrari M, De Moraes S. Spontaneous and renal hypertensive rats: responsiveness of isolated right and left atria to noradrenaline, isoprenaline and methoxamine. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 1994; 46:1-8. [PMID: 8120335 DOI: 10.1016/0165-1838(94)90138-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The adrenergic responsiveness of right and left atria isolated from spontaneously hypertensive rats (SHR) and renal hypertensive rats (RHR) was studied. Right atria isolated from SHR showed subsensitivity to the chronotropic effect of noradrenaline (21.3-fold at the EC50 level, P < 0.05) and isoprenaline (12.0-fold, P < 0.05). However, atria isolated from RHR did not exhibit any significant alteration (P > 0.05) in sensitivity to the chronotropic effect of noradrenaline or isoprenaline. Chronotropic responsiveness to theophylline was not altered in right atria isolated from SHR or RHR. alpha 1-Mediated inotropic responses to noradrenaline and methoxamine were blunted in left atria isolated from SHR. Left atria isolated from RHR showed supersensitivity to the inotropic effect of noradrenaline (5.4-fold at the EC50 level, P < 0.05) and subsensitivity to the inotropic effect of methoxamine (6.0-fold, P < 0.05). It is concluded that the present results could, at least partially, explain the reduced cardiac output observed during established hypertension in SHR and the increased cardiac output observed in the initial phase of renal hypertension in RHR.
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Affiliation(s)
- M Q Turrin
- Department of Pharmacology, University of São Paulo, Brazil
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29
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Vleeming W, Wemer J, Riezebos J, Van Amsterdam JG, De Wildt DJ, Porsius AJ. Modulation by pertussis toxin of salbutamol- and arecoline-induced effects in the isolated heart and aorta of the rat. Eur J Pharmacol 1993; 250:415-22. [PMID: 8112401 DOI: 10.1016/0014-2999(93)90028-g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The modulatory effects of pertussis toxin pretreatment on responses mediated via beta-adrenoceptors and muscarinic acetylcholine receptors were investigated in isolated rat hearts and aortic rings 4 days after in vivo administration of pertussis toxin. In isolated hearts, pertussis toxin increased heart weight and baseline coronary flow values but did not effect baseline left ventricular pressure values. In unpaced hearts, pertussis toxin inhibited the arecoline-induced cardiac standstill, while in paced hearts, the beta 2-adrenoceptor agonist salbutamol produced a dose-dependent vasodilation with similar characteristics in pertussis toxin and control preparations. Pertussis toxin had no effect on myocardial or aortic cyclic nucleotide levels and the myocardial beta-adrenoceptor density (Bmax) and dissociation constant (Kd). In precontracted aortic rings, pertussis toxin had no effect on the salbutamol or arecoline induced vasorelaxation. In summary, we demonstrated a reduced cholinergic responsiveness in isolated hearts but an intact beta 2-adrenoceptor pathway in isolated hearts as well as in isolated aortic rings after pertussis toxin pretreatment. In aortic rings no change in muscarinic acetylcholine receptor responsiveness occurred.
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MESH Headings
- Albuterol/pharmacology
- Animals
- Aorta/drug effects
- Aorta/physiology
- Arecoline/pharmacology
- Coronary Circulation/drug effects
- Dose-Response Relationship, Drug
- Heart/drug effects
- Heart/physiology
- In Vitro Techniques
- Male
- Nucleotides, Cyclic/metabolism
- Organ Size/drug effects
- Pertussis Toxin
- Rats
- Rats, Wistar
- Receptors, Adrenergic, beta/drug effects
- Receptors, Adrenergic, beta/metabolism
- Receptors, Muscarinic/drug effects
- Receptors, Muscarinic/metabolism
- Vasodilation/drug effects
- Virulence Factors, Bordetella/pharmacology
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Affiliation(s)
- W Vleeming
- Faculty of Pharmacy, University Utrecht, Netherlands
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30
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Abstract
The human heart contains both beta 1 and beta 2-adrenoceptors; both mediate positive inotropic and chronotropic effects. In chronic heart failure, beta-adrenoceptor number is reduced, presumably, by down-regulation by endogenous noradrenaline which is elevated due to increased sympathetic activity. Since the human heart contains only a few spare receptors for beta-adrenoceptor-mediated positive inotropic effects and the amount of spare receptors declines in chronic heart failure, it is not surprising that the reduced beta-adrenoceptor number is accompanied by decreased contractile responses to beta-adrenoceptor agonists (including endogenous catecholamines), and the extent of decrease in maximal inotropic response is more pronounced as the disease becomes more advanced. Moreover, in chronic heart failure myocardial G(i)-protein, which inhibits cAMP formation, is increased, which might further contribute to the reduction in beta-adrenoceptor-mediated effects. It appears that, at present, the best therapy for severe heart failure is a successful heart transplant, since in the transplanted heart beta-adrenoceptor number and function seems to be normalized. Moreover, the data currently available do not suggest any development of super- or subsensitivity of postsynaptic cardiac beta-adrenoceptors in the transplanted human heart.
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Affiliation(s)
- O E Brodde
- Abtlg. Nieren- & Hochdruckkrankheiten, Universitätsklinikum Essen, Germany
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31
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Steinfath M, Lavicky J, Schmitz W, Scholz H, Döring V, Kalmár P. Changes in cardiac beta-adrenoceptors in human heart diseases: relationship to the degree of heart failure and further evidence for etiology-related regulation of beta 1 and beta 2 subtypes. J Cardiothorac Vasc Anesth 1993; 7:668-73. [PMID: 7905755 DOI: 10.1016/1053-0770(93)90050-u] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Radioligand binding studies were performed to investigate total beta-adrenoceptor density (Bmax) and beta 1 and beta 2 subtype distribution in left ventricular biopsies obtained from 8 prospective transplant donors serving as controls and from 143 patients with different degrees of heart failure (NYHA class II to IV) undergoing aortic or mitral valve surgery due to aortic or mitral stenosis, aortic or mitral regurgitation, as well as combined aortic or mitral valve lesions (stenosis and regurgitation). In 13 other patients, heart failure was due to hypertrophic obstructive cardiomyopathy (N = 6, NYHA III), tetralogy of Fallot (N = 4, NYHA III), or Becker's muscular dystrophy (N = 3, NYHA IV). Bmax was assessed by (-)-(125I)-iodocyanopindolol used as radioligand. Competition experiments with the highly selective beta 1-adrenoceptor antagonist CGP 20712A were performed for determination of beta 1- and beta 2-adrenoceptor subtypes. In biopsies taken from transplant donors, the Bmax was found to be 70.1 +/- 5.8 fmol/mg protein. In all groups investigated the extent of total beta-adrenoceptor downregulation was related to the degree of heart failure. The decrease in Bmax was found to be about 20% (NYHA II), 45% (NYHA III), and 60% (NYHA IV) when compared with controls. There was no significant difference in the reduction of total beta-adrenoceptor density between isolated aortic or mitral valve diseases and combined valve lesions. Independent of the degree of heart failure, selective downregulation of the beta 1 subtype was found in patients with isolated or combined aortic valve diseases, hypertrophic obstructive cardiomyopathy, and Becker's muscular dystrophy.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M Steinfath
- Department of Anesthesiology, University of Hamburg, Germany
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32
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Gumanova NG, Akhmedzhanov NM, Varentsov SI, Gerasimova CI, Bulargina TV, Shakhov YA. The GTP-binding regulatory proteins, Gs and G(i), are altered in erythrocyte membranes of patients with ischemic heart disease resulting from coronary atherosclerosis. ARTERIOSCLEROSIS AND THROMBOSIS : A JOURNAL OF VASCULAR BIOLOGY 1993; 13:1244-51. [PMID: 8343499 DOI: 10.1161/01.atv.13.8.1244] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Acute ischemic heart disease is associated with alterations in the cardiac adenylate cyclase system response, although the specificity and mechanism of these events are unknown. We studied the characteristics of inhibitory (G(i)) and stimulatory (Gs) GTP-binding regulatory proteins (G proteins) of adenylate cyclase in erythrocyte membranes of patients (n = 16) with nonacute ischemic heart disease resulting from coronary atherosclerosis. Gs was measured by reconstitution with the resolved catalytic unit of adenylate cyclase and by cholera toxin-catalyzed ADP-ribosylation of a 42-kD protein; G(i) was tested as a 41-kD substrate of pertussis toxin-catalyzed ADP-ribosylation. Gs activity was decreased by 27 +/- 2% in the cholate extract and by 25 +/- 3% in the supernatant of guanosine 5'-(gamma-thio)triphosphate-treated membranes. The amount of cholera toxin substrate was decreased by 33 +/- 3%, and the pertussis toxin substrate was increased by 27 +/- 5% compared with healthy subjects (n = 10). All changes in G-protein characteristics appear to be specific relative to other erythrocyte membrane proteins and hemoglobin. Those patients who have a decreased Gs possess approximately normal Gi, and those with increased G(i) showed no change in Gs. Patients with increased G(i) (normal Gs) exhibited more severe deterioration of their coronary arteries than did patients with decreased Gs (normal G(i)) (P < .05), but these two groups did not differ significantly in serum lipids, hormones, drug therapy, historical data, or baseline assessment (P < 0.05).
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33
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Scholz J, Steinfath M, Roewer N, Patten M, Troll U, Schmitz W, Scholz H, Schulte am Esch J. Biochemical changes in malignant hyperthermia susceptible swine: cyclic AMP, inositol phosphates, alpha 1, beta 1- and beta 2-adrenoceptors in skeletal and cardiac muscle. Acta Anaesthesiol Scand 1993; 37:575-83. [PMID: 8213023 DOI: 10.1111/j.1399-6576.1993.tb03768.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
It has been presumed that alteration in the concentrations of second messengers leads to alterations in the function of the ryanodine receptor. Consequently, we have determined the basal content of cyclic AMP and inositol phosphates in skeletal and cardiac muscle of malignant hyperthermia (MH) susceptible (MHS) and healthy normal control (MHN) swine. Since alpha 1- and beta-adrenoceptors are linked to these second messenger systems, the densities of alpha 1- and beta-adrenoceptors were also determined. In skeletal as well as cardiac muscle, a higher basal concentration of almost all of the inositol phosphates was found. Of all inositol phosphates measured, the presumed second messenger inositol 1,4,5-trisphosphate (1,4,5-IP3) was mostly concentrated in both tissues. Each MHS sample contained more 1,4,5-IP3 than the highest value observed in MHN muscle, indicating that a threshold of 1,4,5-IP3 concentration for determination of MHS or MHN status can be defined. In addition, MHS skeletal muscle contained more cAMP than MHN, whereas there was no difference between MHS and MHN in cardiac muscle. The changes observed in the different inositol phosphate and cAMP contents were not accompanied by an altered alpha 1- or beta-adrenoceptor density in skeletal or cardiac muscle between MHS and MHN. However, the total number of beta-adrenoceptors of MHN and MHS was significantly higher in cardiac (about 80 fmol/mg protein) than skeletal muscles (about 30 fmol/mg protein). The cardiac muscles revealed about 80% beta 1- and beta 2- and 20% beta 2-adrenoceptors, whereas skeletal muscles were characterized by over 95% beta 2-adrenoceptors.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J Scholz
- Department of Anesthesiology, University Hospital Eppendorf, Hamburg, Germany
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34
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Kozlik-Feldmann R, Kramer HH, Wicht H, Feldmann R, Netz H, Reinhardt D. Distribution of myocardial beta-adrenoceptor subtypes and coupling to the adenylate cyclase in children with congenital heart disease and implications for treatment. J Clin Pharmacol 1993; 33:588-95. [PMID: 8396157 DOI: 10.1002/j.1552-4604.1993.tb04709.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
In congestive heart failure, down-regulation of myocardial beta-adrenoceptors (beta-AR) due to an elevated sympathetic tone is well known. In infancy and childhood, heart failure is usually related to congenital heart disease (CHD). Therefore, 71 samples of right atrial tissue of infants and children with CHD undergoing cardiac surgery were studied for beta-adrenoceptor density and distribution of the beta 1-/beta 2-AR subtypes. In 49 cases, the coupling of the beta-AR to the adenylate cyclase (AC) was examined. In a further study of 19 myocardial samples, AC was selectively stimulated with beta 1- or beta 2-AR whereas the other subtype was blocked by an antagonist. The following results were obtained: (1) Infants and children with severe acyanotic or cyanotic CHD had severely reduced beta-AR densities. (2) In most of the cases, the beta-AR down regulation is beta 1-subtype selective, but in critically ill newborns with congenital aortic valve stenosis or transposition of the great arteries, there is additional significant beta 2-AR down-regulation. In Fallot patients treated with the beta-antagonist propranolol, a significant increased beta-AR number compared with untreated Fallot patients was found. (3) beta-Adrenoceptor reduction in CHD is correlated with elevated noradrenaline plasma levels, thus proving a sympathetic dysregulation. (4) In CHD with moderate hemodynamic load, beta 2-AR coupling to AC was markedly more efficient than beta 1-AR coupling. The small number of myocardial beta 2-AR produced most of the cyclic adenosine monophosphate. (5) In severe acyanotic and cyanotic CHD, a partial decoupling of the beta 2-AR to the AC occurred.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- R Kozlik-Feldmann
- Children's Hospital, Ludwig-Maximilians-University of Munich, Germany
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35
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Pitschner HF, Droege A, Mitze M, Schlepper M, Brodde OE. Down-regulated beta-adrenoceptors in severely failing human ventricles: uniform regional distribution, but no increased internalization. Basic Res Cardiol 1993; 88:179-91. [PMID: 8389122 DOI: 10.1007/bf00798266] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
In chronic heart failure cardiac beta-adrenoceptors are decreased. In this study we investigated whether a) in severely failing human ventricles beta-adrenoceptors are uniformly decreased or regional variations exist, and b) the beta-adrenoceptor decrease is caused by increased internalization or is a real loss in beta-adrenoceptors. For this purpose we assessed beta-adrenoceptor number and subtype distribution in a particulate fraction (mainly sarcolemmal plasma membranes) and a light vesicle fraction of right and left ventricular segments (obtained by cutting transversal rings of 2 cm from the midventricular regions) of explanted hearts from 2 patients with end-stage congestive dilated cardiomyopathy (DCM) and one patient with end-stage ischemic cardiomyopathy (ICM). In all three hearts ventricular beta-adrenoceptor number was very low (7.5-10 and 21-26 fmol/mg protein in DCM, 15-22 fmol/mg protein in ICM compared to 68-74 fmol/mg protein in non-failing ventricles). beta-Adrenoceptors were uniformly decreased over the whole ventricular region and no considerable regional variations existed. The same held true for beta 1- and beta 2-adrenoceptors. In ICM decrease in beta-adrenoceptors was due to a concomitant reduction in beta 1- and beta 2-adrenoceptors, in DCM it was mainly caused by beta 1-adrenoceptor down-regulation. In all ventricular segments investigated light vesicle beta-adrenoceptors amounted to about 5-7% of total ventricular beta-adrenoceptors, and this was not significantly different from non-failing left ventricles. We conclude that a) in severely failing human ventricles beta-adrenoceptors are evenly down-regulated and no regional variations exist, and b) the decrease in beta-adrenoceptors is not due to enhanced internalization but is a real loss of beta-adrenoceptors.
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36
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Ungerer M, Böhm M, Elce JS, Erdmann E, Lohse MJ. Altered expression of beta-adrenergic receptor kinase and beta 1-adrenergic receptors in the failing human heart. Circulation 1993; 87:454-63. [PMID: 8381058 DOI: 10.1161/01.cir.87.2.454] [Citation(s) in RCA: 550] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
BACKGROUND In chronic heart failure, the positive inotropic effects of beta-adrenergic receptor agonists are greatly reduced, in part as a result of two alterations of the cardiac beta-adrenergic receptors: loss of their function (receptor uncoupling) and reduction of their number (downregulation). In vitro studies have shown that a major mechanism leading to beta-adrenergic receptor uncoupling involves phosphorylation of the receptors by the specific beta-adrenergic receptor kinase (beta ARK). METHODS AND RESULTS We have therefore investigated expression of beta ARK and beta-adrenergic receptors in samples from the left ventricles of patients with dilated cardiomyopathy or ischemic cardiomyopathy and from nonfailing control ventricles. Contractile responses to beta-receptor stimulation were decreased in the failing hearts compared with control hearts, whereas those to forskolin and calcium remained unchanged. The messenger RNA (mRNA) levels of beta ARK, beta 1- and beta 2-receptors, and of glyceraldehyde phosphate dehydrogenase and beta-actin as controls were measured by quantitative polymerase chain reactions. In addition, beta ARK enzyme activity assays were performed, and the levels of beta 1- and beta 2-receptors were determined by radioligand binding. beta ARK mRNA levels were increased almost threefold in both forms of heart failure, and beta ARK activity was enhanced. beta 1-Receptor mRNA levels and beta 1-receptor numbers were decreased by approximately 50% in both failing groups, whereas these levels were unaltered for beta 2-receptors. There were no differences between dilated and ischemic cardiomyopathy for any of these parameters. CONCLUSIONS In addition to other alterations found in failing hearts, the diminished response to beta-receptor agonists appears to involve the combined effects of enhanced expression of beta ARK and reduced expression of beta 1-receptors.
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Affiliation(s)
- M Ungerer
- Laboratorium für Molekulare Biologie, Universität München, Max-Planck-Institut für Biochemie, Martinsried, FRG
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37
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Dhalla NS, Dixon IM, Suzuki S, Kaneko M, Kobayashi A, Beamish RE. Changes in adrenergic receptors during the development of heart failure. Mol Cell Biochem 1992; 114:91-5. [PMID: 1461261 DOI: 10.1007/bf00240302] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Moderate and severe stages of congestive heart failure due to the loss of myocardium upon coronary occlusion in rats was associated with an increase in alpha-adrenergic receptors and a decrease in beta-adrenergic receptors in the viable left ventricle. However, at early stages of heart failure the number of beta-adrenergic receptors was decreased without any changes in the number of alpha-adrenergic receptors. The affinities of these receptors to alpha receptor antagonist (3H-prazosin) and beta receptor antagonist (3H-dihydroalprenolol) were not altered in the failing hearts. On the other hand, the pattern of changes in both alpha- and beta-adrenergic receptors in heart membranes treated with oxygen free radical generating system was different from that seen in the failing hearts. In particular, the affinities for these receptors were decreased whereas the number of beta-receptors was increased and the number of alpha-receptors was decreased or unchanged. These results indicate that alterations in the adrenergic receptors in heart failure are not due to the formation of oxygen free radicals.
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Affiliation(s)
- N S Dhalla
- Division of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, Winnipeg, Manitoba, Canada
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38
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von der Leyen H, Steinfath M, Hecht A, Schmitz W, Scholz H, Neumann K, Haverich A, Heublein B. Changes in cardiac beta 1- and beta 2-adrenoceptor densities after human cardiac transplantation: relation to transplant coronary vasculopathy and pretransplantation disease. Am Heart J 1992; 124:686-93. [PMID: 1325108 DOI: 10.1016/0002-8703(92)90279-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In 100 patients 12 to 60 months after cardiac transplantation, the influence of transplant coronary vasculopathy and of the pretransplantation disease (end-stage heart failure caused by coronary artery disease or dilated cardiomyopathy) on the beta-adrenergic receptor (AR) numbers and beta 1/beta 2-AR ratio of right ventricular biopsies was determined. Patients with coronary vasculopathy (CVP) after cardiac transplantation had lower absolute numbers of beta 1-AR compared with patients without CVP. Since patients with CVP had increased left ventricular (LV) end-diastolic pressure and LV muscle mass, it is suggested that decreased beta 1-AR may be the result of an altered hemodynamic situation of the transplanted heart after development of CVP. Patients with dilated cardiomyopathy (DCM) before cardiac transplantation showed a decrease in total beta-AR and of the beta 1/beta 2-AR ratio as a result of an increase in beta 2-AR and a decrease in beta 1-AR numbers. The decreased beta 1/beta 2-AR ratio in patients with previous DCM may indicate that the beta-AR system of the transplanted heart might be influenced (at least in part) by pathophysiologic factors that are characteristic of the pretransplantation disease ultimately leading to cardiac transplantation and persisting after cardiac transplantation.
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Affiliation(s)
- H von der Leyen
- Abteilüng Kardiologie Nephrologie, Medizinische Hochschule Hannover, Germany
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39
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Steinfath M, Danielsen W, von der Leyen H, Mende U, Meyer W, Neumann J, Nose M, Reich T, Schmitz W, Scholz H. Reduced alpha 1- and beta 2-adrenoceptor-mediated positive inotropic effects in human end-stage heart failure. Br J Pharmacol 1992; 105:463-9. [PMID: 1348446 PMCID: PMC1908677 DOI: 10.1111/j.1476-5381.1992.tb14276.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
1. alpha 1-Adrenoceptor (phenylephrine in the presence of propranolol) and beta 2-adrenoceptor (fenoterol)-mediated positive inotropic effects were investigated in human ventricular preparations isolated from five non-failing (prospective organ donors) and from eight explanted failing hearts with end-stage idiopathic dilative cardiomyopathy (NYHA IV). 2. For comparison, the nonselective beta-adrenoceptor agonist isoprenaline, the phosphodiesterase (PDE) inhibitor 3-isobutyl-1-methylxanthine (IBMX), the cardiac glycoside dihydroouabain, and calcium were studied. 3. Furthermore, the influence of IBMX on adenosine 3':5'-cyclic monophosphate (cyclic AMP) PDE activity as well as total beta-adrenoceptor density, beta 1- and beta 2-adrenoceptor subtype distribution, and alpha 1-adrenoceptor density were compared in nonfailing and failing human heart preparations. The radioligands (-)-[125I]-iodocyanopindolol for beta-adrenoceptor binding and [3H]-prazosin for alpha 1-adrenoceptor binding were used. 4. The inotropic responses to calcium and dihydroouabain in failing human hearts were unchanged, whereas the maximal alpha 1- and beta 2-adrenoceptor-mediated positive inotropic effects were greatly reduced. The inotropic effects of the other cyclic AMP increasing compounds, i.e. isoprenaline and IBMX, were also reduced to about 60% of the effects observed in nonfailing controls. The potency of these compounds was decreased by factors 4-10. 5. The basal PDE activity and the PDE inhibition by IBMX were similar in nonfailing and failing preparations. 6. The total beta-adrenoceptor density in nonfailing hearts was about 70 fmol mg-1 protein. In failing hearts the total number of beta-adrenoceptors was markedly reduced by about 60%. The betal/beta2-adrenoceptor ratio was shifted from about 80/20% in nonfailing to approximately 60/40% in failing hearts which was due to a selective reduction of beta1-adrenoceptors. The beta2-adrenoceptor population remaining unchanged. alpha-Adrenoceptor density was increased from about 4 fmol mg-' protein in nonfailing to 10 fmol mgprotein in failing hearts.7. Changes in PDE activity and adrenoceptor downregulation cannot completely explain the reduced positive inotropic effects of alpha 1- and beta 2-adrenoceptor agonists in failing human hearts. This supports the hypothesis that impairment of other processes such as the coupling between receptor and effector system, i.e. the respective G-proteins, are equally important in end-stage heart failure.
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Affiliation(s)
- M Steinfath
- Abteilung Allgemeine Pharmakologie, Universitäts-Krankenhaus Eppendorf, Universität Hamburg, Germany
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