1
|
de Moura AL, Brum PC, de Carvalho AETS, Spadari RC. Effect of stress on the chronotropic and inotropic responses to β-adrenergic agonists in isolated atria of KOβ2 mice. Life Sci 2023; 322:121644. [PMID: 37004731 DOI: 10.1016/j.lfs.2023.121644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 03/06/2023] [Accepted: 03/26/2023] [Indexed: 04/03/2023]
Abstract
Altered sensitivity to the chronotropic and inotropic effects of catecholamines and reduction in β1/β2-adrenoceptor (β1/β2-AR) ratio were reported in failing and in senescent human heart, as well as in isolated atria and ventricle of rats submitted to stress. This was due to downregulation of β1-AR with or without up-regulation of β2-AR. AIMS To investigate the stress-induced behavior of β1-AR in the heart of mice expressing a non-functional β2-AR subtype. The guiding hypothesis is that the absence of β2-AR signaling will not affect the behavior of β1-AR during stress and that those are independent processes. MATERIALS AND METHODS The chronotropic and inotropic responses to β-AR agonists in isolated atria of stressed mice expressing a non-functional β2-AR were analyzed. The mRNA and protein expressions of β1- and β2-AR were also determined. KEY FINDINGS No deaths were observed in mice under stress protocol. Atria of stressed mice displayed reduced sensitivity to isoprenaline compared to the controls, an effect that was abolished by the β2- and β1-AR antagonists 50 nM ICI118,551 and 300 nM CGP20712A, respectively. Sensitivity and maximum response to the β-agonists dobutamine and salbutamol were not altered by stress or ICI118,551. The responses to dobutamine and salbutamol were prevented by CGP20712A. The expression of β1-AR was reduced at protein levels. SIGNIFICANCE Collectively, our data provide evidence that the cardiac β2-AR is not essential for survival in a stressful situation and that the stress-induced reduction of β1-AR expression was independent of the β2-AR presence.
Collapse
|
2
|
Effects of renal denervation on blood-pressure response to hemorrhagic shock in spontaneously hypertensive rats. Chin J Traumatol 2018; 21:293-300. [PMID: 30342984 PMCID: PMC6235792 DOI: 10.1016/j.cjtee.2018.09.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 03/31/2018] [Accepted: 04/19/2018] [Indexed: 02/04/2023] Open
Abstract
PURPOSE Renal denervation (RD) has been demonstrated to be an effective approach to reduce blood pressure for those with resistant hypertension. Yet, we aimed to explore the effect and possible mechanism of RD on blood-pressure response to hemorrhagic shock in spontaneously hypertensive rats. METHODS A total of 48 male spontaneously hypertensive rats were randomized to three groups: study group, sham-operation group and control group. RD was achieved by cutting off renal nerves and swabbing phenol on it. Ten weeks after RD, 8 rats in each group were sacrificed to collect the kidney and heart tissues. The remaining rats were subjected to an operation to induce hemorrhagic shock which would lead to 40% loss of total blood volume, and observed for 120 min. The serum concentration of norepinephrine was measured before and three weeks after RD. RESULTS The blood-pressure and norepinephrine levels were reduced significantly after RD (p < 0.05). Systolic blood pressure and diastolic blood pressure of the surgery group were higher than those in the sham and control groups at 15, 30 and 45 min after hemorrhagic shock (p < 0.05), while no significant difference was observed at 60, 90 and 120 min (p > 0.05). Additionally, the beta-1 adrenergic receptor (β1-AR) in the study group was significantly higher than those in the other two groups (p < 0.05) after hemorrhagic shock. CONCLUSION This study demonstrated that RD could to some extent improve blood-pressure response to hemorrhagic shock in an established model of severe hemorrhagic shock in spontaneously hypertensive rats. The mechanism might be associated with up-regulation of β1-AR.
Collapse
|
3
|
Treinys R, Bogdelis A, Rimkutė L, Jurevičius J, Skeberdis VA. Differences in the control of basal L-type Ca(2+) current by the cyclic AMP signaling cascade in frog, rat, and human cardiac myocytes. J Physiol Sci 2016; 66:327-36. [PMID: 26676115 PMCID: PMC10716949 DOI: 10.1007/s12576-015-0430-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 11/26/2015] [Indexed: 12/20/2022]
Abstract
β-adrenergic receptors (β-ARs) mediate the positive inotropic effects of catecholamines by cAMP-dependent phosphorylation of the L-type Ca(2+) channels (LTCCs), which provide Ca(2+) for the initiation and regulation of cell contraction. The overall effect of cAMP-modulating agents on cardiac calcium current (I Ca,L) and contraction depends on the basal activity of LTCCs which, in turn, depends on the basal activities of key enzymes involved in the cAMP signaling cascade. Our current work is a comparative study demonstrating the differences in the basal activities of β-ARs, adenylyl cyclase, phosphodiesterases, phosphatases, and LTCCs in the frog and rat ventricular and human atrial myocytes. The main conclusion is that the basal I Ca,L, and consequently the contractile function of the heart, is secured from unnecessary elevation of its activity and energy consumption at the several "checking-points" of cAMP-dependent signaling cascade and the loading of these "checking-points" may vary in different species and tissues.
Collapse
Affiliation(s)
- Rimantas Treinys
- Institute of Cardiology, Lithuanian University of Health Sciences, Sukilėlių pr. 17, 50009, Kaunas, Lithuania
| | - Andrius Bogdelis
- Institute of Cardiology, Lithuanian University of Health Sciences, Sukilėlių pr. 17, 50009, Kaunas, Lithuania
| | - Lina Rimkutė
- Institute of Cardiology, Lithuanian University of Health Sciences, Sukilėlių pr. 17, 50009, Kaunas, Lithuania
| | - Jonas Jurevičius
- Institute of Cardiology, Lithuanian University of Health Sciences, Sukilėlių pr. 17, 50009, Kaunas, Lithuania
| | - Vytenis Arvydas Skeberdis
- Institute of Cardiology, Lithuanian University of Health Sciences, Sukilėlių pr. 17, 50009, Kaunas, Lithuania.
| |
Collapse
|
4
|
Li X, Wang B, Cui H, Du Y, Song Y, Yang L, Zhang Q, Sun F, Luo D, Xu C, Chu W, Lu Y, Yang B. let-7e replacement yields potent anti-arrhythmic efficacy via targeting beta 1-adrenergic receptor in rat heart. J Cell Mol Med 2014; 18:1334-43. [PMID: 24758696 PMCID: PMC4124018 DOI: 10.1111/jcmm.12288] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 02/19/2014] [Indexed: 01/02/2023] Open
Abstract
Beta-adrenoceptor (β-AR) exerts critical regulation of cardiac function. MicroRNAs (miRNAs) are potentially involved in a variety of biological and pathological processes. This study aimed to investigate the role of miRNA let-7e in the up-regulation of β1-AR and arrhythmogenesis in acute myocardial infarction (AMI) in rats. β1-AR expression was significantly up-regulated and let-7a, c, d, e and i were markedly down-regulated in the infarcted heart after 6 and 24 hrs myocardial infarction. Forced expression of let-7e suppressed β1-AR expression at the protein level, without affecting β1-AR mRNA level, in neonatal rat ventricular cells (NRVCs). Silencing of let-7e by let-7e antisense inhibitor (AMO-let-7e) enhanced β1-AR expression at the protein level in NRVCs. Administration of the lentivirus vector containing precursor let-7e (len-pre-let-7e) significantly inhibited β1-AR expression in rats, whereas len-AMO-let-7e up-regulated β1-AR relative to the baseline control level, presumably as a result of depression of tonic inhibition of β1-AR by endogenous let-7e. Len-negative control (len-NC) did not produce significant influence on β1-AR expression. Len-pre-let-7e also profoundly reduced the up-regulation of β1-AR induced by AMI and this effect was abolished by len-AMO-let-7e. Importantly, len-pre-let-7e application significantly reduced arrhythmia incidence after AMI in rats and its anti-arrhythmic effect was cancelled by len-AMO-let-7e. Notably, anti-arrhythmic efficacy of len-pre-let-7e was similar to propranolol, a non-selective β-AR blocker and metoprolol, a selective β1-AR blocker. Down-regulation of let-7e contributes to the adverse increase in β1-AR expression in AMI and let-7e supplement may be a new therapeutic approach for preventing adverse β1-AR up-regulation and treating AMI-induced arrhythmia.
Collapse
Affiliation(s)
- Xin Li
- Department of Pharmacology (Key Laboratory of Cardiovascular Medicine Research, Ministry of Education; State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), Harbin Medical University, Harbin, Heilongjiang, China
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Agüero J, Almenar L, D'Ocon P, Oliver E, Montó F, Rueda J, Vicente D, Martínez-Dolz L, Salvador A. Myocardial and peripheral lymphocytic transcriptomic dissociation of beta-adrenoceptors and G protein-coupled receptor kinases in heart transplantation. J Heart Lung Transplant 2009; 28:1166-71. [PMID: 19782607 DOI: 10.1016/j.healun.2009.06.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2009] [Revised: 06/06/2009] [Accepted: 06/06/2009] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND The genetic expression of adrenergic receptors plays an important pathophysiologic role in heart failure. G protein-coupled receptor kinases (GRKs) desensitize the beta-receptor to catecholaminergic stimulation. It has been suggested that their mRNA expression in peripheral lymphocytes could mirror the changes in their myocardial expression in the failing heart, but this relationship between the myocyte and lymphocyte has not been studied in heart transplantation (HT). The objective of this study was to analyze adrenergic receptor and GRK mRNA expression in myocardium and lymphocytes and their correlation. METHODS Twenty-three HT patients without evidence of acute rejection or echocardiographic dysfunction were assessed. Myocardial biopsy samples and peripheral blood lymphocytes were obtained, and alpha(1)- and beta-adrenoceptor subtype and GRK subtype mRNA was analyzed using reverse transcript-polymerase chain reaction (RT-PCR). RESULTS Mean age was 45 +/- 15 years, with a median of time since HT of 205 (351) days. In biopsies, the beta(1)/beta(2)-adrenoceptor ratio was 57%/42%, and GRK5 was the most commonly expressed, followed by GRK2. In lymphocytes, the beta(1)/beta(2) ratio was 3%/96%, whereas GRK2 mRNA expression was greater than that of other subtypes. There was no correlation between myocardial and lymphocyte parameters. There were no correlations with clinical variables, but lymphocyte beta(2) and GRK2 were increased with time since HT. CONCLUSIONS In the transplanted heart, there is no correlation between mRNA expression of adrenoceptors and GRKs in myocardium and peripheral lymphocytes. With time since transplant, mRNA expression of lymphocyte but not myocardial beta(2)-adrenoceptor and GRK2 increases. Therefore, this dissociation between myocardial and lymphocyte mRNA expression limits the potential use of peripheral blood samples for diagnosis of graft dysfunction.
Collapse
Affiliation(s)
- Jaime Agüero
- Heart Failure and Transplant Unit, Department of Cardiology, La Fe University Hospital, Plaza Mestre Vicente Ballester 2-13, Valencia, Spain.
| | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Rickenbacher A, Seiler R, Honegger U, Shaw SG, Balsiger BM. Role of β1-, β2-, and β3-adrenoceptors in contractile hypersensitivity in a model of small bowel transplantation. Surgery 2008; 143:94-102. [DOI: 10.1016/j.surg.2007.06.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Revised: 06/15/2007] [Accepted: 06/30/2007] [Indexed: 11/15/2022]
|
7
|
Zhou S, Paz O, Cao JM, Asotra K, Chai NN, Wang C, Chen LS, Fishbein MC, Sharifi B, Chen PS. Differential β-adrenoceptor expression induced by nerve growth factor infusion into the canine right and left stellate ganglia. Heart Rhythm 2005; 2:1347-55. [PMID: 16360089 DOI: 10.1016/j.hrthm.2005.08.027] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2005] [Accepted: 08/28/2005] [Indexed: 11/27/2022]
Abstract
BACKGROUND Nerve growth factor (NGF) infusion into the right stellate ganglion (RSG) is antiarrhythmic, while NGF infusion into the left stellate ganglion (LSG) is proarrhythmic in dogs with myocardial infarction (MI) and complete atrioventricular block (CAVB). This functional asymmetry suggests differential neural remodeling. OBJECTIVES To test the hypothesis that NGF infusion into the RSG and the LSG can lead to differential beta-adrenoceptor (beta-AR) expression in dogs with MI and CAVB. METHODS AND RESULTS We performed immunostaining to quantify beta(1)-AR and beta(3)-AR immunoreactivity in six dogs with MI and CAVB, nine dogs with MI, CAVB, and NGF infusion to the LSG, six dogs with MI, CAVB, and NGF infusion to the RSG, and six normal dogs. There was significantly increased beta(3)-AR immunoreactivity in dogs with NGF infusion into the LSG and significantly decreased beta(3)-AR immunoreactivity in dogs with NGF infusion into the RSG compared with controls and with the MI and CAVB group. There were no significant differences in beta(1)-AR immunoreactivity among these four groups. To determine protein and mRNA expression of beta-ARs, we created MI and CAVB and infused NGF into the LSG in six additional dogs. The noninfarcted left ventricle free wall was harvested 1 week later. The protein level and receptor density of beta(3)-AR (but not beta(1)- or beta(2)-AR) significantly increased in these six dogs compared with normal controls. CONCLUSIONS We conclude that NGF infusion into the RSG and the LSG in dogs with MI and CAVB induced differential beta(3)-AR expression in the left ventricular myocardium.
Collapse
Affiliation(s)
- Shengmei Zhou
- Division of Cardiology, Department of Medicine, University of Southern California, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Balsiger BM, Sarr MG. Chronic extrinsic denervation of the small bowel: effect on adrenergic and cholinergic contractile mechanisms in canine ileal circular muscle. Surgery 2003; 134:783-90. [PMID: 14639357 DOI: 10.1016/s0039-6060(03)00255-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Small bowel transplantation necessitates chronic extrinsic denervation and is often followed by enteric dysfunction. Our aim was to study canine ileal contractile activity after extrinsic denervation. METHODS In vitro dose responses to cholinergic and adrenergic agonists were evaluated in canine ileal muscle strips in control subjects and after jejunoileal extrinsic denervation (EX DEN) at 0, 2, and 8 weeks after operative preparation. RESULTS Spontaneous activity and the increased activity after tetrodotoxin (enteric nerve blockade) did not differ between groups. Response to acetylcholine and bethanechol did not differ at any time in the control or EX DEN group. In contrast, the EX DEN group demonstrated a procontractile hypersensitivity to norepinephrine at 2 and 8 weeks that was not seen in the control group. This adrenergic hypersensitivity in the EX DEN group was insensitive to intramural neural blockade with tetrodotoxin. CONCLUSIONS Extrinsic denervation does not affect basal contractile activity, augmented contractile activity to intramural neural blockade, nor response to cholinergic agonists. However, it induces a procontractile adrenergic hypersensitivity in canine ileal circular muscle mediated at the level of the smooth muscle and not at the enteric nervous system.
Collapse
Affiliation(s)
- Bruno M Balsiger
- Gastroenterology Unit, Inselspital, University of Bern, 3010 Bern, Switzerland
| | | |
Collapse
|
9
|
Balsiger BM, He CL, Zyromski NJ, Sarr MG. Neuronal adrenergic and muscular cholinergic contractile hypersensitivity in canine jejunum after extrinsic denervation. J Gastrointest Surg 2003; 7:572-582. [PMID: 12763419 DOI: 10.1016/s1091-255x(02)00154-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Extrinsic denervation may be responsible for motor dysfunction after small bowel transplantation. The aim of this study was to examine the role of extrinsic innervation of canine jejunum on contractile activity. An in vitro dose response of cholinergic and adrenergic agonists was evaluated in canine jejunal strips of circular muscle at 0, 2, and 8 weeks in a control group and after jejunoileal extrinsic denervation (EX DEN). Neurons in circular muscle were quantitated by means of immunohistochemical techniques. Adrenergic and cholinergic responses did not differ at any time in the control group. However, at 2 and 8 weeks, extrinsic denervation caused an increased sensitivity to the procontractile effects of the cholinergic agonist bethanechol at the level of the smooth muscle cells, and increased sensitivity to the inhibitory effects of the adrenergic agent norepinephrine mediated at the level of the enteric nervous system. Immunohistochemical analysis showed a reduction in all neurons and a complete lack of adrenergic fibers in the EX DEN group after 2 and 8 weeks. Extrinsic denervation induces enteric neuronal cholinergic and adrenergic smooth muscle hypersensitivity in canine jejunal circular muscle.
Collapse
Affiliation(s)
- Bruno M Balsiger
- Department of Visceral and Transplantation Surgery, University of Bern, Bern, Switzerland
| | - Chong-Liang He
- Department of Surgery and the Gastroenterology Research Unit, Mayo Clinic, Rochester, Minnesota
| | | | - Michael G Sarr
- Department of Surgery and the Gastroenterology Research Unit, Mayo Clinic, Rochester, Minnesota
| |
Collapse
|
10
|
Moniotte S, Vaerman JL, Kockx MM, Larrouy D, Langin D, Noirhomme P, Balligand JL. Real-time RT-PCR for the detection of beta-adrenoceptor messenger RNAs in small human endomyocardial biopsies. J Mol Cell Cardiol 2001; 33:2121-33. [PMID: 11735259 DOI: 10.1006/jmcc.2001.1475] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Quantification of mRNAs from extremely small human samples remains a challenge. Requiring minimal amounts of tissue and no post-reaction manipulation, real-time reverse transcriptase-polymerase chain reaction (RT-PCR) is an attractive method to quantitatively assess the expression of rare mRNAs. We evaluated the applicability of the technique on RNA extracted from human endomyocardial biopsies and isolated cardiomyocytes, and compared the technique to the RT-competitive PCR approach. Primers and probes were designed to amplify the three subtypes of human beta -adrenoceptors (beta1-, beta2- and beta3 AR), as well as reference genes such as glyceraldehyde-3-phosphate dehydrogenase (GAPDH), Hypoxanthine-guanine phosphoribosyltransferase (HPRT), and the oncogene ABL by real-time RT-PCR. Specific primers and a deleted competitor were synthetized to compare the quantitation of the beta 3 AR mRNA expression by RT-competitive PCR. We validated the technique on human cardiomyocytes either freshly isolated or selectively excised from fixed sections of human myocardium by Laser Capture Microdissection. The standard curves obtained for the cDNA's analysed showed mean slopes comprised between -3.3 and -3.7. Inter- and intra-assay variability of gene quantitation was reflected by mean values of the variance coefficients of Ct of 4.84+/-1.13% and 2.73+/-0.39% or 3.32+/-1.03% and 2.21+/-0.24% (corresponding to percent variances of copy numbers of 83.07+/-12.72% and 34.45+/-9.03% or 47.40+/-8.59% and 23.83+/-3.16%) for human beta3 AR and GAPDH genes, respectively. The expression of GAPDH, HPRT and ABL mRNA was characterized by a very low dispersion of individual values across cardiac pathologies, suggesting that these genes may be used as reference genes in quantitative PCR studies. Finally, we applied the technique to detect rare mRNAs, such as beta -AR mRNAs, from small human endomyocardial biopsies and even isolated cardiomyocytes. Real-time RT-PCR is appropriate to quantitate rare messenger RNAs, including in extremely small human tissue samples. This method appears very promising for futures studies of gene expression in several pathophysiological conditions, including heart failure.
Collapse
Affiliation(s)
- S Moniotte
- Department of Internal Medicine, Unit of Pharmacology and Therapeutics, University of Louvain Medical School, Brussels, Belgium
| | | | | | | | | | | | | |
Collapse
|
11
|
Gerber BL, Bernard X, Melin JA, Delestinne T, Vanbutsele R, Goenen M, Vanoverschelde JL. Exaggerated chronotropic and energetic response to dobutamine after orthotopic cardiac transplantation. J Heart Lung Transplant 2001; 20:824-32. [PMID: 11502404 DOI: 10.1016/s1053-2498(01)00277-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND After heart transplantation, the transplanted denervated heart displays both an exaggerated chronotropic and an exaggerated inotropic response to circulating catecholamines. This study assessed whether denervated transplanted hearts also display an exaggerated energetic response when challenged with dobutamine. METHODS AND RESULTS A total of 18 heart transplant recipients and 14 normal volunteers underwent measurements of myocardial oxygen consumption (MVO2), external work (EW), and pressure-volume area (PVA), at rest and during infusion of dobutamine. At rest, calculated myocardial (PVA/MVO2) and mechanical (EW/MVO2) efficiencies were similar among transplant recipients and normal volunteers. During low-dose dobutamine infusion (8 microg/kg/min), transplant recipients exhibited a larger increase in heart rate (to 126 +/- 14 vs 87 +/- 26 beats/min, p < 0.001) and MVO2 (to 269 +/- 43 vs 233 +/- 19 J/min/100g, p < 0.05) and a smaller increase in EW (64 +/- 18 vs 72 +/- 13 J/min/100g, p < 0.05) and PVA (70 +/- 16 vs 81 +/- 13 J/min/100g, p < 0.05) than did normal volunteers. As a result, both myocardial (26 +/- 4 vs 35 +/- 4%, p < 0.05) and mechanical (23 +/- 4 vs 30 +/- 4%, p < 0.001) efficiencies were lower during dobutamine infusion in transplant recipients than in normal volunteers. During the infusion of a higher dose of dobutamine (19 microg/kg/min), the chronotropic and inotropic responses of heart transplant recipients were even more exaggerated. The fall in myocardial efficiency induced by dobutamine correlated with the increase in heart rate (r = -0.58) and could be reproduced in normal volunteers by coadministration of atropine. CONCLUSIONS Transplant recipients exhibit a larger fall in contractile efficiency and a larger oxygen-wasting effect during dobutamine infusion than do normal volunteers. Because normal volunteers pre-medicated with atropine presented with a similar increase in heart rate and a similar fall in efficiency, the exaggerated energetic response of transplanted hearts to dobutamine likely resulted from the same mechanisms as their chronotropic supersensitivity, i.e., the loss of inhibitory parasympathetic innervation.
Collapse
Affiliation(s)
- B L Gerber
- Division of Cardiology, Université Catholique de Louvain, School of Medicine, Brussels, Belgium
| | | | | | | | | | | | | |
Collapse
|
12
|
Affiliation(s)
- S F Steinberg
- Departments of Pharmacology and Medicine, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
| |
Collapse
|
13
|
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
| | | | | |
Collapse
|
14
|
Hakim K, Fischer M, Günnicker M, Poenicke K, Zerkowski HR, Brodde OE. Functional role of beta2-adrenoceptors in the transplanted human heart. J Cardiovasc Pharmacol 1997; 30:811-6. [PMID: 9436822 DOI: 10.1097/00005344-199712000-00017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In the transplanted human heart, beta-adrenoceptor subtypes change with time after transplantation: beta1-adrenoceptors tend to decline, whereas beta2-adrenoceptors are upregulated. The aim of this study was to determine whether, in the transplanted human heart, stimulation of beta2-adrenoceptors can induce heart-rate increases. For this purpose, we assessed in eight heart-transplant recipients (mean posttransplant time: 932 days) the effects of infusion of graded doses of isoprenaline (3.5-35 ng/kg/min) 120 min after pretreatment with the beta1-adrenoceptor antagonist bisoprolol (10 mg p.o.; beta1-adrenoceptor occupancy approximately 80%; beta2-adrenoceptor occupancy <5%) on heart rate in the recipient's native (innervated) and transplanted (denervated) sinus nodes. Isoprenaline, acting under these conditions predominantly at beta2-adrenoceptors, increased heart rate both in the recipient's transplanted and native sinus nodes in a dose-dependent manner; at each dose, increases were significantly higher in the transplanted than in the native sinus node. ED20 values (dose to increase heart rate by 20 beats/min) in the transplanted sinus node were 22.2 +/- 1.8 ng/kg/min, and in the native, >35 ng/kg/min (p < 0.01). We conclude that in the transplanted human heart, beta2-adrenoceptor stimulation does evoke increases in heart rate. The enhanced response to isoprenaline in the transplanted sinus node could be caused by the upregulated beta2-adrenoceptors or by the fact that during isoprenaline infusion, vagal activity increases, thus blunting the response in the native (innervated) but not in the transplanted (denervated) sinus node.
Collapse
Affiliation(s)
- K Hakim
- Clinic for Cardio-Thoracic Surgery, Martin Luther University of Halle-Wittenberg, Halle/Saale, Germany
| | | | | | | | | | | |
Collapse
|
15
|
Rechavia E, de Silva R, Kushwaha SS, Rhodes CG, Araujo LI, Jones T, Maseri A, Yacoub MH. Enhanced myocardial 18F-2-fluoro-2-deoxyglucose uptake after orthotopic heart transplantation assessed by positron emission tomography. J Am Coll Cardiol 1997; 30:533-8. [PMID: 9247529 DOI: 10.1016/s0735-1097(97)00180-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVES We sought to assess the relation between glucose metabolism, myocardial perfusion and cardiac work after orthotopic heart transplantation. BACKGROUND The metabolic profile of the transplanted cardiac muscle is affected by the lack of sympathetic innervation, impaired inotropic function, chronic vasculopathy, allograft rejection and immunosuppressive therapy. In relation to myocardial perfusion and cardiac work, glucose metabolism has not previously been studied in heart transplant recipients. METHODS Regional myocardial blood flow (ml.min-1.g-1) and 18F-2-fluoro-2-deoxyglucose (18FDG) uptake rate (ml.s-1.g-1) were measured after an overnight fast in 9 healthy male volunteers (mean age +/- SD 32 +/- 7 years) and in 10 male patients (mean age 50 +/- 10 years) who had a nonrejecting heart transplant, normal left ventricular function and no angiographic evidence of epicardial coronary sclerosis. Measurements were made by using dynamic positron emission tomography (PET) with 15O-labeled water and 18FDG, respectively. Heart rate and blood pressure were also measured for calculation of rate-pressure product. RESULTS 18FDG uptake was similar in all heart regions in the patients and volunteers (intrasubject regional variably 12 +/- 8% and 16 +/- 12%, respectively, p = 0.51). Regional myocardial blood flow was similarly evenly distributed (intrasubject regional variability 14 +/- 10% and 12 +/- 8%, respectively, p = 0.67). Mean 18FDG uptake and myocardial blood flow values for the whole heart are given because no regional differences were identified. 18FDG uptake was on average 196% higher in the patients than in the volunteers (2.90 +/- 1.79 x 10(-4) vs. 0.98 +/- 0.38 x 10(-4) ml.s-1.g-1, p = 0.006). Regional myocardial blood flow and rate-pressure product were similarly increased in the patient group, but by only 41% (1.14 +/- 0.3 vs. 0.81 +/- 0.13 ml.min-1.g-1, p = 0.008) and 53% (11,740 +/- 2,830 vs. 7,689 +/- 1,488, p = 0.001), respectively. CONCLUSIONS 18FDG uptake is homogeneously increased in normally functioning nonrejecting heart transplants. This finding suggests that glucose may be a preferred substrate in the transplanted heart. The magnitude of this observed increase is significantly greater than that observed for myocardial blood flow or cardiac work. In the patient group, the latter two variables were increased to a similar degree over values in control hearts, indicating a coupling between cardiac work load and myocardial blood flow. The disproportionate rise in 18FDG uptake may be accounted for by inefficient metabolic utilization of glucose by the transplanted myocardium or by the influence of circulating catecholamines, which may stimulate glucose uptake independently of changes in cardiac work load.
Collapse
Affiliation(s)
- E Rechavia
- Cyclotron Unit, Royal Postgraduate Medical School, Hammersmith Hospital, London, United Kingdom
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Bartunek J, Shah AM, Vanderheyden M, Paulus WJ. Dobutamine enhances cardiodepressant effects of receptor-mediated coronary endothelial stimulation. Circulation 1997; 95:90-6. [PMID: 8994422 DOI: 10.1161/01.cir.95.1.90] [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: 02/03/2023]
Abstract
BACKGROUND In humans, intracoronary infusion of substance P reduces left ventricular end-systolic pressure and left ventricular peak systolic pressure because of earlier onset of left ventricular relaxation induced by paracrine myocardial action of mediators released from the coronary endothelium. The present study investigated in humans the effects of beta-adrenergic stimulation, which also induces earlier left ventricular relaxation, on the left ventricular myocardial contractile response to intracoronary infusion of substance P. METHODS AND RESULTS Data were obtained in 13 patients after cardiac transplantation and in 3 patients with dilated nonischemic cardiomyopathy. Microtip left ventricular pressure recordings were obtained during a 5-minute intracoronary infusion of substance P (20 pmol/min) under control conditions and then repeated during concurrent intravenous administration of dobutamine. In the presence of dobutamine, intracoronary substance P caused a greater fall in left ventricular end-systolic pressure (transplantation control, -9 +/- 11 versus transplantation dobutamine, -20 +/- 18 mm Hg [P < .05]; cardiomyopathy control, -4 +/- 1 versus cardiomyopathy dobutamine, -10 +/- 3 mm Hg [P < .05]) and in left ventricular peak systolic pressure (transplantation control, -14 +/- 10 versus transplantation dobutamine, -30 +/- 22 mm Hg [P < .01]; cardiomyopathy control, -9 +/- 7 versus cardiomyopathy dobutamine, -15 +/- 6 mm Hg [P = .1]). CONCLUSIONS Dobutamine enhances the cardiodepressant effect on myocardial contractile performance of receptor-mediated coronary endothelial stimulation in transplant recipients and in patients with dilated nonischemic cardiomyopathy. This enhancement could result from a potentiating interaction of the relaxation-hastening effect exerted by beta-adrenergic stimulation and by mediators released from the coronary endothelium, such as nitric oxide.
Collapse
|
17
|
Brodde OE, Adamczyk M, Busch F, Bossaller C, Duske E, Fleck E, Götze S, Auch-Schwelk W. Selective downregulation of rat cardiac beta 1-adrenoceptors by cyclosporine A: prevention by diltiazem or angiotensin-converting enzyme inhibitors. J Am Coll Cardiol 1995; 25:761-7. [PMID: 7860926 DOI: 10.1016/0735-1097(94)00425-p] [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: 01/27/2023]
Abstract
OBJECTIVES This study attempted to determine whether long-term treatment with cyclosporine A in rats affects cardiac beta 1-adrenoceptors and whether this can be prevented by angiotensin-converting enzyme inhibitors or calcium-entry blocking agents. BACKGROUND In the transplanted human heart the density of beta 1-adrenoceptors decreases with time after transplantation, whereas that of beta 2-adrenoceptors does not. Because heart transplant recipients are treated with cyclosporine A, we studied whether administration of cyclosporine A in rats might cause this beta 1-adrenoceptor downregulation. METHODS We performed two studies. First, we treated groups of 10 male normotensive Wistar rats orally with 30 mg/kg body weight per day of cyclosporine A, 10 mg/kg per day of enalapril and 60 mg/kg per day of diltiazem, alone or in combination, for 6 weeks each. Second, we treated groups of 15 male normotensive Wistar rats orally with 15 mg/kg per day of cyclosporine A and 10 mg/kg per day of lisinopril, alone or in combination, for 6 weeks each. At the end of each treatment regimen, cardiac beta-adrenoceptor density and subtype distribution were assessed by (-)-[125I]iodocyanopindolol binding. RESULTS Both doses of cyclosporine A caused a significant decrease in cardiac beta 1-adrenoceptor density without affecting beta 2-adrenoceptor density. Although diltiazem and the angiotensin-converting enzyme inhibitors alone did not affect cardiac beta-adrenoceptors, they prevented the cyclosporine A-induced downregulation of beta 1-adrenoceptors. CONCLUSIONS In normotensive Wistar rats, cyclosporine A causes a significant decrease in cardiac beta 1-adrenoceptors without affecting beta 2-adrenoceptors. This can be prevented by diltiazem or angiotensin-converting enzyme inhibitors. In heart transplant recipients, who undergo long-term treatment with cyclosporine A, there is a very similar beta 1-adrenoceptor down-regulation with time after transplantation. Thus, administration of cyclosporine A may cause these beta-adrenoceptor subtype alterations.
Collapse
Affiliation(s)
- O E Brodde
- Department of Internal Medicine, University of Essen, Germany
| | | | | | | | | | | | | | | |
Collapse
|
18
|
White M, Roden R, Minobe W, Khan MF, Larrabee P, Wollmering M, Port JD, Anderson F, Campbell D, Feldman AM. Age-related changes in beta-adrenergic neuroeffector systems in the human heart. Circulation 1994; 90:1225-38. [PMID: 8087932 DOI: 10.1161/01.cir.90.3.1225] [Citation(s) in RCA: 171] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Aging decreases cardiac beta-adrenergic responsiveness in model systems and in humans in vivo. The purpose of this study was to comprehensively evaluate the age-related changes in the beta-receptor-G protein-adenylyl cyclase complex in nonfailing human hearts. METHODS AND RESULTS Twenty-six nonfailing explanted human hearts aged 1 to 71 years were obtained from organ donors and subjected to pharmacological investigation of beta-adrenergic neuroeffector systems. When the population was subdivided into the 13 youngest and 13 oldest subjects, total beta-receptor density assessed by maximum [125I]ICYP binding (beta max) was reduced in older hearts by 37% in left ventricles and 31% in right ventricles (both P < .05), and the downregulation was confined to the beta 1 subtype (r = .78 left ventricle beta 1 density versus donor age). Older donor hearts exhibited a 3- to 4-fold rightward shift of ICYP-isoproterenol (ISO) competition curves and demonstrated 43% fewer receptors in a high-affinity agonist binding state (P < .05). Older hearts exhibited decreased adenylyl cyclase stimulation by ISO, by zinterol (beta 2-agonist), and by the G protein-sensitive probes forskolin, Gpp(NH)p, and NaF. In contrast, there was no change in response to manganese, a specific activator of the adenylyl cyclase catalytic subunit. Toxin-catalyzed ADP ribosylation in membranes prepared from older versus younger hearts revealed a 29% to 30% reduction (P < .05) with cholera toxin (Gs) but no difference with pertussis toxin (Gi). The systolic contractile response of isolated right ventricular trabeculae to ISO was decreased by 46%, with a 10-fold increase in ISO EC50 in older relative to younger donor hearts. CONCLUSIONS There is a profound decrease in cardiac beta-adrenergic responsiveness with aging. This occurs by multiple mechanisms including downregulation and decreased agonist binding of beta 1-receptors, uncoupling of beta 2-receptors, and abnormal G protein-mediated signal transduction.
Collapse
Affiliation(s)
- M White
- Division of Cardiology, University of Utah Medical Center, Salt Lake City
| | | | | | | | | | | | | | | | | | | |
Collapse
|