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Boknik P, Eskandar J, Hofmann B, Zimmermann N, Neumann J, Gergs U. Role of Cardiac A 2A Receptors Under Normal and Pathophysiological Conditions. Front Pharmacol 2021; 11:627838. [PMID: 33574762 PMCID: PMC7871008 DOI: 10.3389/fphar.2020.627838] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 12/15/2020] [Indexed: 12/12/2022] Open
Abstract
This review presents an overview of cardiac A2A-adenosine receptors The localization of A2A-AR in the various cell types that encompass the heart and the role they play in force regulation in various mammalian species are depicted. The putative signal transduction systems of A2A-AR in cells in the living heart, as well as the known interactions of A2A-AR with membrane-bound receptors, will be addressed. The possible role that the receptors play in some relevant cardiac pathologies, such as persistent or transient ischemia, hypoxia, sepsis, hypertension, cardiac hypertrophy, and arrhythmias, will be reviewed. Moreover, the cardiac utility of A2A-AR as therapeutic targets for agonistic and antagonistic drugs will be discussed. Gaps in our knowledge about the cardiac function of A2A-AR and future research needs will be identified and formulated.
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Affiliation(s)
- P. Boknik
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Westfälische Wilhelms-Universität, Münster, Germany
| | - J. Eskandar
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Westfälische Wilhelms-Universität, Münster, Germany
| | - B. Hofmann
- Cardiac Surgery, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - N. Zimmermann
- Bundesinstitut für Arzneimittel und Medizinprodukte, Bonn, Germany
| | - J. Neumann
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - U. Gergs
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
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Pagel PS, Crystal GJ. The Discovery of Myocardial Preconditioning Using Volatile Anesthetics: A History and Contemporary Clinical Perspective. J Cardiothorac Vasc Anesth 2018; 32:1112-1134. [DOI: 10.1053/j.jvca.2017.12.029] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Indexed: 12/24/2022]
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Voors AA, Düngen HD, Senni M, Nodari S, Agostoni P, Ponikowski P, Bax JJ, Butler J, Kim RJ, Dorhout B, Dinh W, Gheorghiade M. Safety and Tolerability of Neladenoson Bialanate, a Novel Oral Partial Adenosine A1 Receptor Agonist, in Patients With Chronic Heart Failure. J Clin Pharmacol 2016; 57:440-451. [DOI: 10.1002/jcph.828] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 09/08/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Adriaan Alexander Voors
- Department of Cardiology; University Medical Center Groningen; University of Groningen; Groningen the Netherlands
| | - Hans-Dirk Düngen
- Department of Cardiology; Campus Virchow, Charite Universitätsmedizin Berlin; Berlin Germany
| | - Michele Senni
- Cardiovascular Department; Ospedale Papa Giovanni XXIII; Bergamo Italy
| | - Savina Nodari
- Cardiology, Department of Medical and Surgical Specialties, Radiological Sciences, and Public Health; University and Civil Hospital of Brescia; Brescia Italy
| | | | | | - Jeroen J. Bax
- Department of Cardiology; Leiden University Medical Center; Leiden the Netherlands
| | - Javed Butler
- Division of Cardiology; Stony Brook University; Stony Brook NY, USA
| | - Raymond J. Kim
- Duke Cardiovascular Magnetic Resonance Center; Duke University Medical Center; Durham NC, USA
| | - Bernard Dorhout
- Department of Cardiology; University Medical Center Groningen; University of Groningen; Groningen the Netherlands
| | - Wilfried Dinh
- Department of Cardiology, Witten, Germany; Drug Discovery, Clinical Sciences, Bayer Pharma AG; Witten University; Wuppertal Germany
| | - Mihai Gheorghiade
- Center for Cardiovascular Innovation; Northwestern University Feinberg School of Medicine; Chicago IL, USA
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Abstract
Adenosine exerts a variety of physiological effects by binding to cell surface G-protein-coupled receptor subtypes, namely, A1, A2a, A2b, and A3. The central physiological role of adenosine is to preclude tissue injury and promote repair in response to stress. In the heart, adenosine acts as a cytoprotective modulator, linking cardiac function to metabolic demand predominantly via activation of adenosine A1 receptors (A1Rs), which leads to inhibition of adenylate cyclase activity, modulation of protein kinase C, and opening of ATP-sensitive potassium channels. Activation of myocardial adenosine A1Rs has been shown to modulate a variety of pathologies associated with ischemic cardiac injury, including arrhythmogenesis, coronary and ventricular dysfunction, apoptosis, mitochondrial dysfunction, and ventricular remodeling. Partial A1R agonists are agents that are likely to elicit favorable pharmacological responses in heart failure (HF) without giving rise to the undesirable cardiac and extra-cardiac effects observed with full A1R agonism. Preclinical data have shown that partial adenosine A1R agonists protect and improve cardiac function at doses that do not result in undesirable effects on heart rate, atrioventricular conduction, and blood pressure, suggesting that these compounds may constitute a valuable new therapy for chronic HF. Neladenoson bialanate (BAY1067197) is the first oral partial and highly selective A1R agonist that has entered clinical development for the treatment of HF. This review provides an overview of adenosine A1R-mediated signaling in the heart, summarizes the results from preclinical and clinical studies of partial A1R agonists in HF, and discusses the potential benefits of these drugs in the clinical setting.
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Moberly SP, Berwick ZC, Kohr M, Svendsen M, Mather KJ, Tune JD. Intracoronary glucagon-like peptide 1 preferentially augments glucose uptake in ischemic myocardium independent of changes in coronary flow. Exp Biol Med (Maywood) 2012; 237:334-42. [PMID: 22345302 DOI: 10.1258/ebm.2011.011288] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
We examined the acute dose-dependent effects of intracoronary glucagon-like peptide (GLP)-1 (7-36) on coronary vascular tone, cardiac contractile function and metabolism in normal and ischemic myocardium. Experiments were conducted in open chest, anesthetized dogs at coronary perfusion pressures (CPP) of 100 and 40 mmHg before and during intracoronary GLP-1 (7-36) infusion (10 pmol/L to 1 nmol/L). Isometric tension studies were also conducted in isolated coronary arteries. Cardiac and coronary expression of GLP-1 receptors (GLP-1R) was assessed by Western blot and immunohistochemical analysis. GLP-1R was present in the myocardium and the coronary vasculature. The tension of intact and endothelium-denuded coronary artery rings was unaffected by GLP-1. At normal perfusion pressure (100 mmHg), intracoronary GLP-1 (7-36) (targeting plasma concentration 10 pmol/L to 1 nmol/L) did not affect blood pressure, coronary blood flow or myocardial oxygen consumption (MVO(2)); however, there were modest reductions in cardiac output and stroke volume. In untreated control hearts, reducing CPP to 40 mmHg produced marked reductions in coronary blood flow (0.50 ± 0.10 to 0.17 ± 0.03 mL/min/g; P < 0.001) and MVO(2) (27 ± 2.3 to 15 ± 2.7 μL O(2)/min/g; P < 0.001). At CPP = 40 mmHg, GLP-1 had no effect on coronary blood flow, MVO(2) or regional shortening, but dose-dependently increased myocardial glucose uptake from 0.11 ± 0.02 μmol/min/g at baseline to 0.17 ± 0.04 μmol/min/g at 1 nmol/L GLP-1 (P < 0.001). These data indicate that acute, intracoronary administration of GLP-1 (7-36) preferentially augments glucose metabolism in ischemic myocardium, independent of effects on cardiac contractile function or coronary blood flow.
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Affiliation(s)
- Steven P Moberly
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202, USA
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Schwarte LA, Schwartges I, Thomas K, Schober P, Picker O. The effects of levosimendan and glibenclamide on circulatory and metabolic variables in a canine model of acute hypoxia. Intensive Care Med 2011; 37:701-10. [PMID: 21380525 PMCID: PMC3058361 DOI: 10.1007/s00134-011-2144-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 01/23/2011] [Indexed: 11/24/2022]
Abstract
PURPOSE To study the effects of pretreatment with levosimendan (LEVO, a Ca²(+)-sensitizer and K (ATP) (+) channel opener) and/or the K (ATP) (+) channel antagonist glibenclamide (GLIB) on systemic hemodynamics, metabolism, and regional gastromucosal oxygenation during hypoxic hypoxemia. METHODS Chronically instrumented, healthy dogs (24-32 kg, n = 6 per group, randomized cross-over design) were repeatedly sedated, mechanically ventilated (FiO₂ ~0.3) and subjected to the following interventions: no pretreatment, LEVO pretreatment, GLIB pretreatment, or combined LEVO + GLIB pretreatment, each followed by hypoxic hypoxemia (FiO₂ ~0.1). We measured cardiac output (CO, ultrasonic flow probes), oxygen consumption (VO₂, indirect calorimetry), and gastromucosal microvascular hemoglobin oxygenation (μHbO₂, spectrophotometry). STATISTICS data are presented as mean ± SEM and compared by one-way ANOVA (direct drug effects within group) and two-way ANOVA (between all hypoxic conditions) both with Bonferroni corrections; p < 0.05. RESULTS In LEVO-pretreated hypoxemia, CO was significantly higher compared to unpretreated hypoxemia. The increased CO was neither associated with an increased VO₂ nor with markers of aggravated anaerobiosis (pH, BE, lactate). In addition, LEVO pretreatment did not further compromise gastromucosal μHbO₂ in hypoxemia. After combined LEVO + GLIB pretreatment, systemic effects of GLIB were apparent, however, CO was significantly higher than during unpretreated and GLIB-pretreated hypoxemia, but equal to LEVO-pretreated hypoxemia, indicating that GLIB did not prevent the increased CO in LEVO-pretreated hypoxia. CONCLUSIONS LEVO pretreatment resulted in improved systemic circulation (CO) during hypoxemia without fueling systemic VO₂, without aggravating systemic anaerobiosis markers, and without further compromising microvascular gastromucosal oxygenation. Thus, LEVO pretreatment may be an option to support the systemic circulation during hypoxia.
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Affiliation(s)
- Lothar A Schwarte
- Department of Anaesthesiology, VU University Medical Center, Amsterdam, The Netherlands.
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McIntosh VJ, Lasley RD. Adenosine receptor-mediated cardioprotection: are all 4 subtypes required or redundant? J Cardiovasc Pharmacol Ther 2011; 17:21-33. [PMID: 21335481 DOI: 10.1177/1074248410396877] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Adenosine is a purine nucleoside, which is produced primarily through the metabolism of adenosine triphosphate (ATP), therefore its levels increase during stressful situations when ATP utilization increases. Adenosine exerts potent cardioprotective effects on the ischemic/reperfused heart, reducing reversible and irreversible myocardial injury. Adenosine receptors (ARs) are G-protein-coupled receptors, and 4 subtypes exist--A(1), A(2A), A(2B), and A(3), all of which have been shown to be cardioprotective. Adenosine receptors are expressed on multiple cardiac cells, including fibroblasts, endothelial cells, smooth muscle cells, and myocytes. Activation of both A(1) and A(3) receptors prior to ischemia has been shown in multiple experimental models to reduce ischemia/reperfusion-induced cardiac injury. Additionally, activation of the A(2A) receptor at the onset of reperfusion has been shown to reduce injury. Most recently, there is evidence that the A(2B) receptor has cardioprotective effects upon its activation. However, controversy remains regarding the precise timing of activation of these receptors required to induce cardioprotection, as well as their involvement in ischemic preconditioning and postconditioning. Adenosine receptors have been suggested to reduce cell death through actions at the mitochondrial ATP-dependent potassium (K(ATP)) channel, as well as protein kinase C and mitogen-activated protein kinase (MAPK) signaling. Additionally, the ability of ARs to interact has been documented, and several recent reports suggest that these interactions play a role in AR-mediated cardioprotection. This review summarizes the current knowledge of the cardioprotective effects of each AR subtype, as well as the proposed mechanisms of AR cardioprotection. Additionally, the role of AR interactions in cardioprotection is discussed.
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Affiliation(s)
- Victoria J McIntosh
- Department of Physiology and Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, MI, USA
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Matheson PJ, Li N, Harris PD, Zakaria ER, Garrison RN. Glucose-induced intestinal vasodilation via adenosine A1 receptors requires nitric oxide but not K(+)(ATP) channels. J Surg Res 2010; 168:179-87. [PMID: 20452612 DOI: 10.1016/j.jss.2010.02.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Revised: 01/27/2010] [Accepted: 02/09/2010] [Indexed: 11/19/2022]
Abstract
BACKGROUND Both nitric oxide (NO) and adenosine A1 receptor activation mediate microvascular vasodilation during intestinal glucose absorption. Our overall hypothesis is that adenosine triphosphate (ATP) utilization during glucose absorption would increase adenosine metabolite release, which acts on adenosine A1 receptors to alter endothelial production of NO and/or activate ATP-dependent potassium channels (K(+)(ATP)) to dilate intestinal microvessels. METHODS Intravital videomicroscopy of the rat jejunum was used to record the vascular responses of inflow (termed 1A) arterioles, proximal (p3A), and distal (d3A) premucosal arterioles during exposure to isotonic glucose or mannitol solutions alone or in the presence of the selective nitric oxide synthase (NOS) inhibitor (L-NMMA), an adenosine A1 receptor antagonist (8-cyclopentyl-1,3-dipropylxanthine (DPCPX)), or a K(+)(ATP) channel inhibitor (glibenclamide). RESULTS As expected, glucose exposure caused rapid dilation of both p3A and d3A arterioles, while mannitol exposure had no effect on microvascular diameters. Adenosine A1 receptor blockade completely prevented glucose-induced dilation of the premucosal arterioles. NOS inhibition significantly blunted the glucose-induced vasodilation of the premucosal arterioles, but had little effect in the mannitol group. Simultaneous application of both the NOS inhibitor and the adenosine A1 receptor antagonist gave the same reduction in glucose-induced dilation of the premucosal arterioles as the adenosine A1 receptor antagonist alone. Blockade of K(+)(ATP) channels with glibenclamide did not attenuate glucose-induced vasodilation of the premucosal arterioles. CONCLUSION These data suggest that glucose-induced vasodilation of premucosal jejunal arterioles is mediated through adenosine A1 receptors, and NO at least partially mediates the adenosine A1 receptor-induced vasodilation. In addition, K(+)(ATP) channels are not involved in premucosal arteriolar vasodilation during intestinal glucose exposure.
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Affiliation(s)
- Paul J Matheson
- Department of Surgery, University of Louisville, Louisville, Kentucky 40292, USA.
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Reichelt ME, Shanu A, Willems L, Witting PK, Ellis NA, Blackburn MR, Headrick JP. Endogenous adenosine selectively modulates oxidant stress via the A1 receptor in ischemic hearts. Antioxid Redox Signal 2009; 11:2641-50. [PMID: 19552606 PMCID: PMC2861535 DOI: 10.1089/ars.2009.2644] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We tested the impact of A1 adenosine receptor (AR) deletion on injury and oxidant damage in mouse hearts subjected to 25-min ischemia/45-min reperfusion (I/R). Wild-type hearts recovered approximately 50% of contractile function and released 8.2 +/- 0.7 IU/g of lactate dehydrogenase (LDH). A1AR deletion worsened dysfunction and LDH efflux (15.2 +/- 2.6 IU/g). Tissue cholesterol and native cholesteryl esters were unchanged, whereas cholesteryl ester-derived lipid hydroperoxides and hydroxides (CE-O(O)H; a marker of lipid oxidation) increased threefold, and alpha-tocopherylquinone [alpha-TQ; oxidation product of alpha-tocopherol (alpha-TOH)] increased sixfold. Elevations in alpha-TQ were augmented by two- to threefold by A1AR deletion, whereas CE-O(O)H was unaltered. A(1)AR deletion also decreased glutathione redox status ([GSH]/[GSSG + GSH]) and enhanced expression of the antioxidant response element heme oxygenase-1 (HO-1) during I/R: fourfold elevations in HO-1 mRNA and activity were doubled by A1AR deletion. Broad-spectrum AR agonism (10 microM 2-chloroadenosine; 2-CAD) countered effects of A1AR deletion on oxidant damage, HO-1, and tissue injury, indicating that additional ARs (A(2A), A(2B), and/or A3) can mediate similar actions. These data reveal that local adenosine engages A1ARs during I/R to limit oxidant damage and enhance outcome selectively. Control of alpha-TOH/alpha-TQ levels may contribute to A1AR-dependent cardioprotection.
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Affiliation(s)
- Melissa E Reichelt
- Heart Foundation Research Center, Griffith University , Southport, Queensland, Australia.
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Abstract
Despite optimal therapy, the morbidity and mortality of coronary heart disease (CHD) remains significant, particularly in patients with diabetes or the metabolic syndrome. New strategies for cardioprotection are therefore required to improve the clinical outcomes in patients with CHD. Ischaemic preconditioning (IPC) as a cardioprotective strategy has not fulfilled it clinical potential, primarily because of the need to intervene before the index ischaemic event, which is impossible to predict in patients presenting with an acute myocardial infarction (AMI). However, emerging studies suggest that IPC-induced protection is mediated in part by signalling transduction pathways recruited at time of myocardial reperfusion, creating the possibility of harnessing its cardioprotective potential by intervening at time of reperfusion. In this regard, the recently described phenomenon of ischaemic postconditioning (IPost) has attracted great interest, particularly as it represents an intervention, which can be applied at time of myocardial reperfusion for patients presenting with an AMI. Interestingly, the signal transduction pathways, which underlie its protection, are similar to those recruited by IPC, creating a potential common cardioprotective pathway, which can be recruited at time of myocardial reperfusion, through the use of appropriate pharmacological agents given as adjuvant therapy to current myocardial reperfusion strategies such as thrombolysis and primary percutaneous coronary intervention for patients presenting with an AMI. This article provides a brief overview of IPC and IPost and describes the common signal transduction pathway they both appear to recruit at time of myocardial reperfusion, the pharmacological manipulation of which has the potential to generate new strategies for cardioprotection.
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Affiliation(s)
- D J Hausenloy
- The Hatter Cardiovascular Institute, University College, London, London, UK
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Gregg A, Bottle SE, Devine SM, Figler H, Linden J, White P, Pouton CW, Urmaliya V, Scammells PJ. Dual acting antioxidant A1 adenosine receptor agonists. Bioorg Med Chem Lett 2007; 17:5437-41. [PMID: 17689079 DOI: 10.1016/j.bmcl.2007.07.035] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2007] [Revised: 07/09/2007] [Accepted: 07/10/2007] [Indexed: 11/20/2022]
Abstract
Herein we report the synthesis and biological evaluation of some potent and selective A(1) adenosine receptor agonists, which incorporate a functionalised linker attached to an antioxidant moiety. N(6)-(2,2,5,5-Tetramethylpyrrolidin-1-yloxyl-3-ylmethyl)adenosine (VCP28, 2e) proved to be an agonist with high affinity (K(i)=50nM) and good selectivity (A(3)/A(1) > or = 400) for the A(1) adenosine receptor. N(6)-[4-[2-[1,1,3,3-Tetramethylisoindolin-2-yloxyl-5-amido]ethyl]phenyl]adenosine (VCP102, 5a) has higher binding affinity (K(i)=7 nM), but lower selectivity (A(3)/A(1)= approximately 3). All compounds bind weakly (K(i)>1 microM) to A(2A) and A(2B) receptors. The combination of A(1) agonist activity and antioxidant activity has the potential to produce cardioprotective effects.
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Affiliation(s)
- Alison Gregg
- Department of Medicinal Chemistry, Victorian College of Pharmacy, Monash University, 381 Royal Parade, Parkville, Vic. 3052, Australia
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Schulze K, Duschek C, Lasley RD, Bünger R. Adenosine enhances cytosolic phosphorylation potential and ventricular contractility in stunned guinea pig heart: receptor-mediated and metabolic protection. J Appl Physiol (1985) 2007; 102:1202-13. [PMID: 17341737 DOI: 10.1152/japplphysiol.00245.2006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mechanisms of adenosine (ADO) protection of reperfused myocardium are not fully understood. We tested the hypothesis that ADO (0.1 mM) alleviates ventricular stunning by ADO A(1)-receptor stimulation combined with purine metabolic enhancements. Langendorff guinea pig hearts were stunned at constant left ventricular end-diastolic pressure by low-flow ischemia. Myocardial phosphate metabolites were measured by (31)P-NMR, with phosphorylation potential {[ATP]/([ADP].[P(i)]), where brackets indicate concentration} estimated from creatine kinase equilibrium. Creatine and IMP, glycolytic intermediates, were measured enzymatically and glycolytic flux and extracellular spaces were measured by radiotracers. All treatment interventions started after a 10-min normoxic stabilization period. At 30 min reperfusion, ventricular contractility (dP/dt, left ventricular pressure) was reduced 17-26%, ventricular power (rate-pressure product) by 37%, and [ATP]/([ADP].[P(i)]) by 53%. The selective A(1) agonist 2-chloro-N(6)-cyclo-pentyladenosine marginally preserved [ATP]/([ADP].[P(i)]) and ventricular contractility but not rate-pressure product. Purine salvage precursor inosine (0.1 mM) substantially raised [ATP]/([ADP].[P(i)]) but weakly affected contractility. The ATP-sensitive potassium channel blocker glibenclamide (50 microM) abolished ADO protection of [ATP]/([ADP].[P(i)]) and contractility. ADO raised myocardial IMP and glucose-6-phosphate, demonstrating increased purine salvage and pentose phosphate pathway flux potential. Coronary hyperemia alone (papaverine) was not cardioprotective. We found that ADO protected energy metabolism and contractility in stunned myocardium more effectively than both the A(1)-receptor agonist 2-chloro-N(6)-cyclo-pentyladenosine and the purine salvage precursor inosine. Because ADO failed to stimulate glycolytic flux, the enhancement of reperfusion, [ATP]/([ADP].[P(i)]), indicates protection of mitochondrial function. Reduced ventricular dysfunction at enhanced [ATP]/([ADP].[P(i)]) argues against opening of mitochondrial ATP-sensitive potassium channel. The results establish a multifactorial mechanism of ADO antistunning, which appears to combine ADO A(1)-receptor signaling with metabolic adenylate and antioxidant enhancements.
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Affiliation(s)
- Karsten Schulze
- Abteilung für Kardiologie und Pneumologie, Campus Benjamin Franklin, Charité Berlin, 12200 Berlin, Germany.
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Glover DK, Ruiz M, Takehana K, Petruzella FD, Rieger JM, Macdonald TL, Watson DD, Linden J, Beller GA. Cardioprotection by adenosine A2A agonists in a canine model of myocardial stunning produced by multiple episodes of transient ischemia. Am J Physiol Heart Circ Physiol 2007; 292:H3164-71. [PMID: 17308004 DOI: 10.1152/ajpheart.00743.2005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We sought to determine whether administration of a very low, nonvasodilating dose of a highly selective adenosine A(2A) receptor agonist (ATL-193 or ATL-146e) would be cardioprotective in a canine model of myocardial stunning produced by multiple episodes of transient ischemia. Twenty-four anesthetized open-chest dogs underwent either 4 (n=12) or 10 cycles (n=12) of 5-min left anterior descending coronary artery (LAD) occlusions interspersed by 5 or 10 min of reperfusion. Left ventricular thickening was measured from baseline through 180 min after the last occlusion-reperfusion cycle. Regional flow was measured with microspheres. In 12 of 24 dogs, A(2A) receptor agonist was infused intravenously beginning 2 min prior to the first occlusion and continuing throughout reperfusion at a dose below that which produces vasodilatation (0.01 microg x kg(-1) x min(-1)). Myocardial flow was similar between control and A(2A) receptor agonist-treated animals, confirming the absence of A(2) receptor agonist-induced vasodilatation. During occlusion, there was severe dyskinesis with marked LAD zone thinning in all animals. After 180 min of reperfusion following the last cycle, significantly greater recovery of LAD zone thickening was observed in A(2A) receptor agonist-treated vs. control animals in both the 4-cycle (91 +/- 7 vs. 56 +/- 12%, respectively; P<0.05) and the 10-cycle (65 +/- 9 vs. 8 +/- 16%, respectively; P<0.05) occlusion groups. The striking amount of functional recovery observed with administration of low, nonvasodilating doses of adenosine A(2A) agonist ATL-193 or ATL-146e supports their further evaluation for the attenuation of postischemic stunning in the clinical setting.
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Affiliation(s)
- David K Glover
- Cardiovascular Division, Department of Medicine, University of Virginia Health System, Charlottesville, VA 22908-0500, USA.
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Yoshimura Y, Kristo G, Keith BJ, Jahania SA, Mentzer RM, Lasley RD. The p38 MAPK inhibitor SB203580 blocks adenosine A(1) receptor-induced attenuation of in vivo myocardial stunning. Cardiovasc Drugs Ther 2005; 18:433-40. [PMID: 15770430 DOI: 10.1007/s10557-004-6220-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
There is considerable evidence implicating a key role for p38 mitogen-activated protein kinase (MAPK) in ischemic and pharmacological preconditioning against myocardial infarction. However, there have been few, if any, studies examining the role of p38 MAPK in the protection of stunned myocardium. The purpose of this study was to determine whether p38 MAPK plays a role in the adenosine A(1) receptor anti-stunning effect in in vivo porcine myocardium. Regional myocardial stunning in anesthetized, open-chest pigs was induced by 15 min of left anterior descending coronary artery (LAD) occlusion and 3 h of reperfusion (RP). Animals were treated with either vehicle (n = 5), AMP579 (70 microg/kg i.v.; 25 microg/kg bolus + 1.5 microg/kg/min for 30 min prior to ischemia, n = 5), the p38 MAPK inhibitor SB203580 (0.25 mg/kg i.v. bolus, n = 4) or a combination of SB203580 plus AMP579 (n = 5). Regional ventricular function was monitored by measurements of segment shortening and load insensitive parameters including preload recruitable stroke work (PRSW) and PRSW area (PRSWA). The ischemic area at risk was similar in all groups and there was no necrosis in any heart. Treatment with AMP579 significantly improved reperfusion regional PRSW and PRSWA compared to vehicle controls. The p38 inhibitor SB203580 alone did not alter the extent of myocardial stunning, but it abolished the beneficial effect of AMP579 pretreatment. These results provide the first evidence that p38 MAPK activation may play an important role in the mechanism by which adenosine agonists attenuate myocardial stunning.
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Affiliation(s)
- Yukihiro Yoshimura
- Department of Surgery, University of Kentucky College of Medicine, Lexington, KY 40536, USA
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Gao E, Kaplan JL, Victain MS, Dalsey WC, de Garavilla L. Adenosine A1 antagonism attenuates beta-adrenergic-resistant sudden hypoxic cardiac insufficiency. Acad Emerg Med 2005; 12:389-95. [PMID: 15860691 DOI: 10.1197/j.aem.2005.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVES In states such as hypoxia, shock, and cardiac arrest, compromised systemic oxygenation or perfusion appears to induce cardiac insufficiency that can be resistant to beta-adrenergic drugs. Elevated levels of adenosine may mediate such beta-adrenergic-resistant cardiac insufficiency via the adenosine A(1) receptor (A(1)AdoR). The objective of this study was to test the hypothesis that selective A(1)AdoR antagonism attenuates hypoxic cardiac insufficiency more efficaciously than beta(1)-adrenergic agonism or nonselective adenosine antagonism. METHODS Rats were paralyzed and ventilated to a pCO(2) level of 35-40 mm Hg. Ten minutes before hypoxia (inspired o(2) concentration = 5%), rats were treated intravenously with one of the following: 0.1 mg/kg BG-9719 (n = 9), 10 mg/kg NPC-205 (n = 10; BG-9719 and NPC-205 are selective A(1)AdoR antagonists, with durations of action of 30-60 minutes and 60-90 minutes, respectively), 10 mg/kg aminophylline (n = 12), 5 microg/kg/min dobutamine (n = 11), or control solutions. These drug doses maximized survival duration in dose-response studies. RESULTS Before hypoxia, cardiac work was increased more by aminophylline and dobutamine than by BG-9719. Mean (+/-SEM) duration of survival (in minutes) after hypoxia increased from <13 (control solutions) to 13.8 (+/-1.4) (dobutamine), 20.0 (+/-1.6) (aminophylline), 31.7 (+/-4.6) (BG-9719), and 40.5 (+/-7.5) (NPC-205) (p < 0.0001). Heart rate and dP/dt decreased rapidly after hypoxia, but decreases were attenuated with BG-9719 and NPC-205 compared with dobutamine (p < 0.05) and tended toward attenuation with aminophylline. CONCLUSIONS BG-9719 and NPC-205 improved survival duration, heart rate, and left ventricular contractility during hypoxia more efficaciously than dobutamine and possibly aminophylline. Selective A(1)AdoR antagonists warrant further study as alternatives to beta-adrenergic agonists in hypoxia, shock, and cardiac arrest, in which compromised systemic perfusion or oxygenation impairs cardiac output.
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Affiliation(s)
- Erhe Gao
- Merck Manuals, UN-D100, Merck & Co., Inc., 785 Jolly Road, Blue Bell, PA 19422, USA
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Gao E, Kaplan JL, Victain MS, Dalsey WC, Garavilla L. Adenosine A 1Antagonism Attenuates β-adrenergic–resistant Sudden Hypoxic Cardiac Insufficiency. Acad Emerg Med 2005. [DOI: 10.1111/j.1553-2712.2005.tb01536.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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17
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Appleman JR, Erion MD. The therapeutic potential of agents acting via purine receptors. Expert Opin Investig Drugs 2005; 7:225-43. [PMID: 15991954 DOI: 10.1517/13543784.7.2.225] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A host of physiological processes associated with the cardiovascular (CV) system, central nervous system (CNS), and a variety of other organ systems and tissues are regulated by agents, primarily adenosine (ado) and adenosine triphosphate (ATP), that act via cell-surface purine receptors. These receptors have therefore been the focus of a variety of programmes directed at the discovery and development of new therapeutic agents, most notably for the treatment of disorders of the CV system. Currently, only a handful of agents, including ado, theophylline, dipyridamole, and ticlopidine, are approved for clinical use. A variety of new agents intended for use in CV disease, disorders of the CNS, such as Parkinson's disease, treatment of pain, inflammatory disorders, and diverse other pathophysiological conditions are in clinical development. Historically, ado receptors have been the primary target. Recent research efforts have begun to examine alternative strategies including agents that modulate endogenous levels of extracellular ado and agents that act via P(2) receptors.
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Affiliation(s)
- J R Appleman
- Metabasis Therapeutics, Inc., San Diego, CA, USA
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18
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de Micheli A, Chávez Domínguez R, Iturralde Torres P, Pastelín G, Medrano GA. Efectos tempranos y tardíos de la adenosina en taquicardias ventriculares experimentales. Rev Esp Cardiol 2005. [DOI: 10.1157/13071890] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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19
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Gan XT, Rajapurohitam V, Haist JV, Chidiac P, Cook MA, Karmazyn M. Inhibition of Phenylephrine-Induced Cardiomyocyte Hypertrophy by Activation of Multiple Adenosine Receptor Subtypes. J Pharmacol Exp Ther 2004; 312:27-34. [PMID: 15452191 DOI: 10.1124/jpet.104.073122] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Plasma adenosine levels are elevated in cardiovascular disease including hypertension and heart failure, and the nucleoside has been proposed to serve as an endogenous antimyocardial remodeling factor. We studied the modulation of phenylephrine-induced hypertrophy by adenosine receptor activation in isolated neonatal cultured ventricular myocytes. Phenylephrine (10 muM) increased cell size by 35% and significantly increased expression of atrial natriuretic peptide. These effects were reduced by the stable adenosine analog 2-chloroadenosine and were completely blocked by the adenosine A(1) receptor agonist N(6)-cyclopentyladenosine (1 microM), the A(2A) receptor agonist 2-p-(2-carboxyethyl)-phenethylamino-5'-N-ethylcarboxamidoadenosine (100 nM), and the A(3) receptor agonist N(6)-(3-iodobenzyl)adenosine-5'-methyluronamide (100 nM). The antihypertrophic effects of all three agonists were completely reversed by their respective antagonists. Phenylephrine significantly up-regulated expression of the immediate early gene c-fos especially within the first 30 min of phenylephrine treatment. These effects were almost completely inhibited by all adenosine receptor agonists. Although phenylephrine also induced early stimulation of both p38 mitogen-activated protein kinase and extracellular signal-regulated kinase, these responses were unaffected by adenosine agonists. The expression of the G-protein regulatory factors RGS2 and RGS4 were increased by nearly 3-fold by phenylephrine treatment although this was completely prevented by adenosine receptor agonists. These agents also blocked the ability of phenylephrine to up-regulate Na/H exchange isoform 1 (NHE1) expression in hypertrophied myocytes. Thus, our results demonstrate an antihypertrophic effect of adenosine acting via multiple receptor subtypes through a mechanism involving down-regulation of NHE1 expression. The ability to prevent regulators of G-protein signaling (RGS) up-regulation further suggests that adenosine receptor activation minimizes signaling which leads to hypertrophic responses.
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Affiliation(s)
- Xiaohong Tracey Gan
- Department of Physiology and Pharmacology, University of Western Ontario, Medical Sciences Building, London, Ontario N6A 5C1, Canada
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Kristo G, Yoshimura Y, Keith BJ, Stevens RM, Jahania SA, Mentzer RM, Lasley RD. Adenosine A1/A2a receptor agonist AMP-579 induces acute and delayed preconditioning against in vivo myocardial stunning. Am J Physiol Heart Circ Physiol 2004; 287:H2746-53. [PMID: 15271662 DOI: 10.1152/ajpheart.00493.2004] [Citation(s) in RCA: 10] [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: 11/22/2022]
Abstract
The purpose of this study was to determine whether the adenosine A1/A2a receptor agonist AMP-579 induces acute and delayed preconditioning against in vivo myocardial stunning. Regional stunning was produced by 15 min of coronary artery occlusion and 3 h of reperfusion (RP) in anesthetized open-chest pigs. In acute protection studies, animals were pretreated with saline, low-dose AMP-579 (15 microg/kg iv bolus 10 min before ischemia), or high-dose AMP-579 (50 microg/kg iv at 14 microg/kg bolus + 1.2 microg.kg(-1).min(-1) for 30 min before coronary occlusion). The delayed preconditioning effects of AMP-579 were evaluated 24 h after administration of saline vehicle or high-dose AMP-579 (50 microg/kg iv). Load-insensitive contractility was assessed by measuring regional preload recruitable stroke work (PRSW) and PRSW area. Acute preconditioning with AMP-579 dose dependently improved regional PRSW: 129 +/- 5 and 100 +/- 2% in high- and low-dose AMP-579 groups, respectively, and 78 +/- 5% in the control group at 3 h of RP. Administration of the adenosine A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (0.7 mg/kg) blocked the acute protective effect of high-dose AMP-579, indicating that these effects are mediated through A1 receptor activation. Delayed preconditioning with AMP-579 significantly increased recovery of PRSW area: 64 +/- 5 vs. 33 +/- 5% in control at 3 h of RP. In isolated perfused rat heart studies, kinetics of the onset and washout of AMP-579 A1 and A2a receptor-mediated effects were distinct compared with those of other adenosine receptor agonists. The unique nature of the adenosine agonist AMP-579 may play a role in its ability to induce delayed preconditioning against in vivo myocardial stunning.
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Affiliation(s)
- Gentian Kristo
- Dept. of Surgery, Univ. of Kentucky College of Medicine, 800 Rose St., Lexington, KY 40536-0298, USA
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Hoffman WE, Albrecht RF, Jonjev ZS. Comparison of adenosine, isoflurane, and desflurane on myocardial tissue oxygen pressure during coronary artery constriction in dogs. J Cardiothorac Vasc Anesth 2003; 17:495-8. [PMID: 12968239 DOI: 10.1016/s1053-0770(03)00156-3] [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: 11/15/2022]
Abstract
OBJECTIVE To compare adenosine-, isoflurane-, or desflurane-induced hypotension with and without left anterior descending (LAD) coronary artery constriction for the effects on myocardial tissue oxygen pressure (PmO(2)) in dogs. DESIGN Prospective, randomized, nonblinded. SETTING University teaching hospital. PARTICIPANTS Male nonpurpose-bred dogs (n = 18). INTERVENTIONS Dogs were anesthetized with 1.5% isoflurane (n = 12) or 8% desflurane (n = 6). A flow probe and balloon occluder were placed on the LAD artery. A probe that measured myocardial oxygen pressure was inserted into the middle myocardium in the LAD region. Myocardial oxygen consumption (MVO(2)) was calculated as LAD flow x arterial minus coronary sinus oxygen content. MEASURES AND MAIN RESULTS Measures were made during hypotension produced by adenosine infusion, 2.8% isoflurane, or 14% desflurane with and without LAD constriction to decrease blood flow 30%. Without LAD artery constriction, adenosine infusion increased LAD flow 90% and MVO(2) 70%, 2.8% isoflurane produced no change in MVO(2), and 14% desflurane decreased MVO(2) 25%, but no treatment changed PmO(2). LAD artery constriction decreased PmO(2) 50% by itself. Adenosine infusion during LAD constriction decreased tissue oxygen pressure an additional 60%, 2.8% isoflurane produced no change, and 14% desflurane increased PmO(2) 100%. CONCLUSION There was an inverse relationship between the effect of adenosine, 2.8% isoflurane, and 14% desflurane on MVO(2) and PmO(2) during ischemia. This is consistent with reports that increasing oxygen demand worsens myocardial ischemia.
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Affiliation(s)
- William E Hoffman
- Department of Anesthesiology and Physiology, University of Illinois at Chicago, Chicago, IL 60612, USA.
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Cosar EO, O'Connor CJ. Hibernation, Stunning, and Preconditioning: Historical Perspective, Current Concepts, Clinical Applications, and Future Implications. Semin Cardiothorac Vasc Anesth 2003. [DOI: 10.1177/108925320300700202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Despite considerable advances, coronary artery disease is the leading cause of morbidity and mortality in the Western world. The development of effective therapeutic strategies for protecting the myocardium from ischemia would have major impact on patients with coronary artery disease. It is now accepted that patients with coronary artery disease can experience prolonged regional ischemic dysfunction that does not necessarily arise from irreversible tissue damage, and to some extent, can be reversed by restoration of blood flow. The initial stages of dysfunction are probably caused by chronic stunning that can be reversed after revascularization, resulting in rapid and complete functional recovery. On the other hand, the more advanced stages of dysfunction likely correspond to chronic hibernation. After revascularization, functional recovery will probably be quite delayed and mostly incomplete. Over the past decade, the possibility that an innate mechanism of myocardial protection might be inducible in the human heart has generated considerable excitement. In the last two decades, there was phenomenal growth in the understanding of the mechanism known as ischemic preconditioning that is responsible for the innate myocardial protection. Continued research and progress in this area may soon lead to the availability of preconditioning-mimetic treatments. The current concepts, mechanisms, and potential clinical applications of myocardial hibernation, stunning, and ischemic preconditioning are reviewed.
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Affiliation(s)
| | - Christopher J. O'Connor
- Department of Anesthesiology, Rush Medical College, Rush-Presbyterian-St. Lukes Medical Center, Chicago, Illinois
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Peart J, Willems L, Headrick JP. Receptor and non-receptor-dependent mechanisms of cardioprotection with adenosine. Am J Physiol Heart Circ Physiol 2003; 284:H519-27. [PMID: 12388277 DOI: 10.1152/ajpheart.00717.2002] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The relative roles of mitochondrial (mito) ATP-sensitive K(+) (mitoK(ATP)) channels, protein kinase C (PKC), and adenosine kinase (AK) in adenosine-mediated protection were assessed in Langendorff-perfused mouse hearts subjected to 20-min ischemia and 45-min reperfusion. Control hearts recovered 72 +/- 3 mmHg of ventricular pressure (50% preischemia) and released 23 +/- 2 IU/g lactate dehydrogenase (LDH). Adenosine (50 microM) during ischemia-reperfusion improved recovery (149 +/- 8 mmHg) and reduced LDH efflux (5 +/- 1 IU/g). Treatment during ischemia alone was less effective. Treatment with 50 microM diazoxide (mitoK(ATP) opener) during ischemia and reperfusion enhanced recovery and was equally effective during ischemia alone. A(3) agonism [100 nM 2-chloro-N(6)-(3-iodobenzyl)-adenosine-5'-N-methyluronamide], A(1) agonism (N(6)-cyclohexyladenosine), and AK inhibition (10 microM iodotubercidin) all reduced necrosis to the same extent as adenosine, but less effectively reduced contractile dysfunction. These responses were abolished by 100 microM 5-hydroxydecanoate (5-HD, mitoK(ATP) channel blocker) or 3 microM chelerythrine (PKC inhibitor). However, the protective effects of adenosine during ischemia-reperfusion were resistant to 5-HD and chelerythrine and only abolished when inhibitors were coinfused with iodotubercidin. Data indicate adenosine-mediated protection via A(1)/A(3) adenosine receptors is mitoK(ATP) channel and PKC dependent, with evidence for a downstream location of PKC. Adenosine provides additional and substantial protection via phosphorylation to 5'-AMP, primarily during reperfusion.
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Affiliation(s)
- Jason Peart
- Heart Foundation Research Centre, School of Health Science, Griffith University Gold Coast Campus, Southport, Queensland 4217, Australia
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Abstract
BACKGROUND Reports show that glyburide, an adenosine triphosphate sensitive potassium (K+ATP) channel blocker, will reverse the myocardial protective effect of inhalational anesthesia. We evaluated the effect of glyburide on myocardial tissue oxygen pressure (PmO2) in dogs anesthetized with desflurane. METHODS Twelve dogs were anesthetized with 8% end-tidal desflurane for baseline anesthesia. A flow probe was placed on the left anterior descending (LAD) artery. A probe that measured PmO2 was inserted into the middle myocardium in the LAD region. After baseline measures, six dogs received i.v. 1 mg kg(-1) of glyburide and six dogs received sham vehicle treatment. After the glyburide or sham treatment, each dog received an i.v. infusion of adenosine 0.1 microg kg(-1) x min(-1), sodium nitroprusside (SNP) 2-4 microg kg(-1) x min(-1) and 14% end-tidal desflurane in random order. RESULTS Glyburide decreased LAD artery flow from 59 +/- 9 ml min(-1) to 30 +/- 6 ml min(-1) (P < 0.05) and PmO2 from 44 +/- 16 mmHg to 30 +/- 9 mmHg (P < 0.05). Adenosine infusion increased LAD artery blood flow 180% in the sham-treated dogs but produced no change in the glyburide-treated dogs. Sodium nitroprusside infusion increased LAD artery flow and decreased PmO2 in both the glyburide- and sham-treated dogs. Desflurane (14%) did not reverse the glyburide-induced vasoconstriction but increased PmO2 to 38 +/- 20 mmHg (P < 0.05). CONCLUSION Glyburide produced myocardial tissue hypoxia, which was not changed by adenosine, worsened by SNP and improved by 14% desflurane. The improvement in PmO2 with desflurane occurred without a change in myocardial blood flow.
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Affiliation(s)
- W E Hoffman
- Department of Anesthesiology, University of Illinois at Chicago, Department of Physiology, West Side Veterans Administration, Chicago, IL 60612, USA.
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Obata T. Adenosine production and its interaction with protection of ischemic and reperfusion injury of the myocardium. Life Sci 2002; 71:2083-103. [PMID: 12204768 DOI: 10.1016/s0024-3205(02)01993-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Adenosine exerts cardioprotective effects on the ischemic myocardium. A flexibly mounted microdialysis probe was used to measure the concentration of interstitial adenosine and to assess the activity of ecto-5'-nucleotidase (a key enzyme responsible for adenosine production) in in vivo rat hearts. The level of adenosine during perfusion of adenosine 5'-adenosine monophosphate (AMP) was given as an index of the activity of ecto-5'-nucleotidase in the tissue. Endogenous norepinephrine (NE) activates both alpha(1)-adrenoceptors and protein kinase C (PKC), which, in turn, activates ecto-5'-nucleotidase via phosphorylation thereby enhancing the production of interstitial adenosine. Histamine-release NE activates PKC, which increased ecto-5'-nucleotidase activity and augmented release of adenosine. Opening of cardiac ATP sensitive K(+) (K(ATP)) channels may cause hydroxyl radical (.OH) generation through NE release. Lysophosphatidylcholine (LPC), an endogenous amphiphiphilic lipid metabolite, also increases the concentration of interstitial adenosine in rat hearts, through the PKC-mediated activation of endogenous ecto-5'-nucleotidase. Nitric oxide (NO) facilitates the production of interstitial adenosine, via guanosine 3',5'-cyclic monophosphate (cGMP)-mediated activation of ecto-5'-nucleotidase as another pathway. These mechanisms play an important role in high sensitivity of the cardiac adenosine system. Adenosine plays an important role as a modulator of ischemic reperfusion injury, and that the production and mechanism of action of adenosine are linked with NE release.
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Affiliation(s)
- Toshio Obata
- Department of Pharmacology and Therapeutics, Oita Medical University, 1-1 Idaigaoka, Hasama, Oita 879-5593, Japan.
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Headrick JP. Apparent activation of cardiovascular A1 adenosine receptors by A3 agonists. Am J Physiol Heart Circ Physiol 2002; 282:H793-6. [PMID: 11820196 DOI: 10.1152/ajpheart.2002.282.2.h793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Gao E, Kaplan JL, Shi Y, Victain M, Dalsey WC, de Garavilla L. Adenosine A1 receptor antagonist prolongs survival in the hypoxic rat. J Cardiovasc Pharmacol 2001; 38:384-94. [PMID: 11486243 DOI: 10.1097/00005344-200109000-00007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The hypothesis that adenosine A1 receptor (A1AdoR) selective antagonism limits cardiac depression and prolongs survival during acute global hypoxia was tested in a postinsult treatment model using KW-3902 ([8-(noradamantan-3-yl)-1,3-dipropylxanthine]), an A1AdoR selective antagonist. Rats were anesthetized, paralyzed, then ventilated with 8% O2 (hypoxia). In protocol I, 5 min after hypoxia, rats were treated with saline, drug vehicle, or KW-3902 (0.1 mg/kg i.v.). In protocol II, KW-3902 treatment occurred 2.5, 5, or 7.5 min after hypoxia. In protocol I, after hypoxia, left ventricular contractility, heart rate, and systemic mean arterial blood pressure decreased rapidly in saline-and vehicle-treated groups. In contrast, KW-3902 significantly attenuated the decline in these variables. Survival time (the time from the commencement of hypoxia until death) was more prolonged with KW-3902 (109.5 +/- 9.1 min) than with saline (37.6 +/- 5.0 min) or vehicle (35.0 +/- 4.2 min) (p < 0.001). In protocol II, survival time increased from 29.2 +/- 5.5 min in the 7.5-min treatment group to 109.5 +/- 9.5 min (5-min group) and 245.9 +/- 26.1 min (2.5-min group; p < 0.001). KW-3902 prolongs survival in this model, presumably by antagonizing A1AdoR-mediated inhibition of cardiac function. Also, treatment efficacy is highly time dependent.
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Affiliation(s)
- E Gao
- Department of Emergency Medicine, Albert Einstein Medical Center, Philadelphia, Pennsylvania, USA
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Yao L, Kato R, Foëx P. Isoflurane-induced protection against myocardial stunning is independent of adenosine 1 (A(1)) receptor in isolated rat heart. Br J Anaesth 2001; 87:258-65. [PMID: 11493499 DOI: 10.1093/bja/87.2.258] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Volatile anaesthetics can pharmacologically enhance the recovery of stunned myocardium, but the mechanism is still unknown. This study sought to determine whether isoflurane attenuates myocardial stunning, and whether the myocardial protection of isoflurane is mediated by adenosine A(1) receptors. Five groups (n=8) of isolated rat hearts were studied in the Langendorff apparatus. The control groups underwent 20-min ischaemia with or without adenosine receptor antagonist (DPCPX, A(1)()selective) treatment (Cont group and DPCPX group). In the isoflurane groups, isoflurane (1.5 MAC) was present throughout the experiment (Iso group) and DPCPX (200 nM) was administered from 10 min before ischaemia (Iso+DPCPX(pre-I) group) or the beginning of reperfusion (Iso+DPCPX(post-I) group) to the end of experiment. The isoflurane groups had a lower end-diastolic pressure than the control groups (P<0.05). Developed pressure recovered to 77, 76, and 82% in Iso, Iso+DPCPX(pre-I) and Iso+DPCPX(post-I) groups, respectively (P<0.05 compared with control groups). LV+dp/dt(max) recovered to 53, 86, 81, 84, and 60% of pre-ischaemic values in Cont, Iso, Iso+DPCPX(pre-I), Iso+DPCPX(post-I), and DPCPX groups. LV-dp/dt(min) recovered to 55, 84, 83, 81, and 62%, respectively. Both LV+dp/dt(max) and LV-dp/dt(min) were significantly different (P<0.05) between control and isoflurane groups during reperfusion. There were no significant differences among the isoflurane groups. Our data show that isoflurane enhances the post-ischaemic functional recovery of isolated rat heart and that block of A(1) receptors does not abolish the beneficial effects of isoflurane. We conclude that A(1)()receptors are not involved in isoflurane-induced myocardial protection in the isolated rat heart.
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Affiliation(s)
- L Yao
- Nuffield Department of Anaesthetics, Oxford University, Radcliffe Infirmary, Woodstock Road, Oxford OX2 6HE, UK
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Kilpatrick EL, Narayan P, Mentzer RM, Lasley RD. Adenosine A3 agonist cardioprotection in isolated rat and rabbit hearts is blocked by the A1 antagonist DPCPX. Am J Physiol Heart Circ Physiol 2001; 281:H847-53. [PMID: 11454590 DOI: 10.1152/ajpheart.2001.281.2.h847] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Adenosine A3 agonists have been shown to protect ischemic rat and rabbit myocardium. However, these agonists have been reported to exert A3 independent effects, and no cardiac A3 receptor has yet been identified. We thus tested whether A3 agonist protection is due to A1 receptor activation. Isolated rat and rabbit hearts were subjected to 25 and 45 min of global ischemia, respectively. Rat hearts pretreated with adenosine (100 microM), the A3 agonist 2-chloro-N6-(3-iodobenzyl)-adenosine-5'-N-methyluronamide (Cl-IB-MECA, 50 nM), and vehicle recovered 73 +/- 2%, 75 +/- 4%, and 46 +/- 4%, respectively, of preischemic left ventricular developed pressure (LVDP) after 30 min of reperfusion. The A1 antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, 100 nM) blocked the beneficial effects of Cl-IB-MECA (51 +/- 5%) and adenosine (47 +/- 6%). In rabbit hearts, the beneficial effects of the A3 agonist N6-(3-iodobenzyl)-adenosine-5'-N-methyluronamide (50 nM) and the A1 agonist 2-chloro-N6-cyclopentyladenosine (100 nM) on postischemic LVDP (75 +/- 4 and 74 +/- 5%, respectively) were blocked by DPCPX (34 +/- 4 and 36 +/- 3%, respectively). The reduction in infarct size with both agonists was also completely blocked by DPCPX. These results suggest that these A3 agonists protect ischemic myocardium via A1 receptor activation.
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Affiliation(s)
- E L Kilpatrick
- Department of Physiology, University of Kentucky College of Medicine, Lexington, Kentucky 40536, USA
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Abstract
During the past two decades (i.e., since 1980), in excess of 1000 published papers have focused on the phenomenon of the 'stunned myocardium', with many of these studies seeking to identify mechanisms-based treatment strategies to attenuate post-ischemic contractile dysfunction. Early investigations focused largely on abrogating the deleterious effects of oxygen-derived free radicals and unfavorable alterations in calcium homeostasis, both considered to contribute significantly to the pathogenesis of the stunned myocardium. More recently, favorable results have also been obtained using a somewhat different paradigm: that is, attempting to capitalize on endogenous cardioprotective mediators, most notably adenosine, nitric oxide, and the ATP-sensitive potassium channel. Now that potential therapeutic candidates have been identified in the experimental laboratory, the as-yet unmet challenge is to translate this information into the design of effective pharmacologic therapies to treat myocardial stunning in the clinical arena.
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Affiliation(s)
- K Przyklenk
- Heart Institute/Research, Good Samaritan Hospital, Los Angeles, CA 90017-2395, USA.
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Gross ER, Gare M, Toller WG, Kersten JR, Warltier DC, Pagel PS. Ethanol Enhances the Functional Recovery of Stunned Myocardium Independent of KATP Channels in Dogs. Anesth Analg 2001. [DOI: 10.1213/00000539-200102000-00003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Gross ER, Gare M, Toller WG, Kersten JR, Warltier DC, Pagel PS. Ethanol enhances the functional recovery of stunned myocardium independent of K(ATP) channels in dogs. Anesth Analg 2001; 92:299-305. [PMID: 11159220 DOI: 10.1097/00000539-200102000-00003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Chronic, intermittent exposure to small amounts of ethanol reduces myocardial infarct size in vivo. We tested the hypothesis that acute administration of ethanol enhances the functional recovery of stunned myocardium and that adenosine triphosphate-dependent potassium (K(ATP)) channels mediate this beneficial effect. Barbiturate-anesthetized dogs were instrumented for measurement of aortic and left ventricular pressure, +dP/dt(max), and subendocardial segment shortening (%SS) and were subjected to five 5-min periods of coronary artery occlusion, each separated by 5 min of reperfusion followed by a 3-h final reperfusion. In four groups (n = 7 each), dogs received 0.9% saline or ethanol (0.25, 0.5, or 1.0 g/kg over 30 min) in a random manner before occlusions and reperfusions. In other groups (n = 7 each), dogs received the K(ATP) channel antagonist glyburide (0.3 mg/kg, IV) 30 min before saline or ethanol (0.25 g/kg) was administered. Dogs receiving saline or glyburide alone demonstrated poor recovery of contractile function during reperfusion (%SS = 0.9% +/- 2.0% and 1.6% +/- 1.2% at 3 h, respectively). Recovery of %SS was enhanced in dogs receiving the 0.25- and 0.5-g/kg doses of ethanol (10.0% +/- 1.8% and 8.6% +/- 2.2% at 3 h, respectively) independent of alterations in hemodynamics or coronary collateral blood flow (radioactive microspheres). Glyburide did not affect improvement of recovery of stunned myocardium produced by ethanol (11.8% +/- 2.2% at 3 h). The results indicate that ethanol enhances the functional recovery of stunned myocardium independent of K(ATP) channels in vivo.
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Affiliation(s)
- E R Gross
- Department of Anesthesiology, the Medical College of Wisconsin, Milwaukee, 53226, USA
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Liang BT, Stewart D, Jacobson KA. Adenosine A1 and A3 receptors: Distinct cardioprotection. Drug Dev Res 2001. [DOI: 10.1002/ddr.1136] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Preconditioning. Brain Inj 2001. [DOI: 10.1007/978-1-4615-1721-4_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Narayan P, Mentzer RM, Lasley RD. Adenosine A1 receptor activation reduces reactive oxygen species and attenuates stunning in ventricular myocytes. J Mol Cell Cardiol 2001; 33:121-9. [PMID: 11133228 DOI: 10.1006/jmcc.2000.1282] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Reactive oxygen species (ROS) formation following brief periods of ischemia or hypoxia is thought to be the underlying cause of myocardial stunning. Adenosine A1 receptor activation prior to ischemia/hypoxia attenuates stunning, although the mechanism for this effect remains unknown. Isolated rat ventricular myocytes loaded with the ROS-sensitive indicator dichlorofluorescin were subjected to 30 min glucose-free hypoxia followed by reoxygenation. Intracellular ROS increased approximately 175% (from pre-hypoxic levels) during reoxygenation while cell shortening decreased approximately 50%. In myocytes pretreated with the adenosine A1 agonist 2-chloro-N(6)-cyclopentyladenosine (CCPA), reoxygenation-induced ROS formation was attenuated by 40% and stunning was attenuated by 50% (compared to untreated myocytes). The mitochondrial K(ATP) channel opener diazoxide mimicked the effects of CCPA. Pretreatment with the mitochondrial K(ATP) channel blocker 5-hydroxydecanoate, or the non-selective K(ATP) channel blocker glibenclamide, blocked the effects of CCPA. These results suggest that adenosine A1 receptor activation attenuates stunning by reducing ROS formation. These effects of A1 receptor activation appear to be dependent on the opening of K(ATP) channels.
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Affiliation(s)
- P Narayan
- Department of Surgery, University of Kentucky College of Medicine, Lexington, KY 40536, USA.
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Lasley RD, Narayan P, Mentzer RM. New insights into adenosine receptor modulation of myocardial ischemia-reperfusion injury. Drug Dev Res 2001. [DOI: 10.1002/ddr.1135] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Bradamante S, Marchesani A, Barenghi L, Paracchini L, de Jonge R, de Jong JW. Glycogen turnover and anaplerosis in preconditioned rat hearts. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1502:363-79. [PMID: 11068179 DOI: 10.1016/s0925-4439(00)00060-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Using (13)C NMR, we tested the hypothesis that protection by preconditioning is associated with reduced glycogenolysis during ischemia. Preconditioned rat hearts showed improved postischemic function and reduced ischemic damage relative to ischemic controls after 30 min stop-flow ischemia and 30 min reperfusion (contractility: 30+/-10 vs. 2+/-2%; creatine kinase release: 41+/-4 vs. 83+/-15 U/g; both P<0.05). Preconditioning decreased preischemic [(13)C]glycogen by 24% (a 10% decrease in total glycogen), and delayed ischemic [(13)C]glycogen consumption by 5-10 min, reducing ischemic glycogenolysis without changing acidosis relative to controls. Upon reperfusion, glycogen synthesis resumed only after preconditioning. Glutamate (13)C-isotopomer analysis showed recovery of Krebs cycle activity with higher anaplerosis than before ischemia (23+/-4 vs. 11+/-3%, P<0.05), but in controls reperfusion failed to restore flux. Compared to control, preconditioning before 20 min ischemia increased contractility (86+/-10 vs. 29+/-14%, P<0.05) and restored preischemic anaplerosis (13+/-3 vs. 39+/-9%, P<0.05). Preconditioning is associated with reduced glycogenolysis early during ischemia. However, protection does not rely on major variations in intracellular pH, as proposed earlier. Our isotopomer data suggest that preconditioning accelerates metabolic and functional recovery during reperfusion by more efficient/active replenishment of the depleted Krebs cycle.
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Affiliation(s)
- S Bradamante
- CNR-Centro Sintesi e Stereochimica di Speciali Sistemi Organici, University of Milan, Milan, Italy.
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Peart J, Headrick JP. Intrinsic A(1) adenosine receptor activation during ischemia or reperfusion improves recovery in mouse hearts. Am J Physiol Heart Circ Physiol 2000; 279:H2166-75. [PMID: 11045950 DOI: 10.1152/ajpheart.2000.279.5.h2166] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We assessed the role of A(1) adenosine receptor (A(1)AR) activation by endogenous adenosine in the modulation of ischemic contracture and postischemic recovery in Langendorff-perfused mouse hearts subjected to 20 min of total ischemia and 30 min of reperfusion. In control hearts, the rate-pressure product (RPP) and first derivative of pressure development over time (+dP/dt) recovered to 57 +/- 3 and 58 +/- 3% of preischemia, respectively. Diastolic pressure remained elevated at 20 +/- 2 mmHg (compared with 3 +/- 1 mmHg preischemia). Interstitial adenosine, assessed by microdialysis, rose from approximately 0.3 to 1.9 microM during ischemia compared with approximately 15 microM in rat heart. Nonetheless, these levels will near maximally activate A(1)ARs on the basis of effects of exogenous adenosine and 2-chloroadenosine. Neither A(1)AR blockade with 200 nM 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) during the ischemic period alone nor A(1)AR activation with 50 nM N(6)-cyclopentyladenosine altered rapidity or extent of ischemic contracture. However, ischemic DPCPX treatment significantly depressed postischemic recovery of RPP and +dP/dt (44 +/- 3 and 40 +/- 4% of preischemia, respectively). DPCPX treatment during the reperfusion period alone also reduced recovery of RPP and +dP/dt (to 44 +/- 2 and 47 +/- 2% of preischemia, respectively). These data indicate that 1) interstitial adenosine is lower in mouse versus rat myocardium during ischemia, 2) A(1)AR activation by endogenous adenosine or exogenous agonists does not modify ischemic contracture in murine myocardium, 3) A(1)AR activation by endogenous adenosine during ischemia attenuates postischemic stunning, and 4) A(1)AR activation by endogenous adenosine during the reperfusion period also improves postischemic contractile recovery.
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Affiliation(s)
- J Peart
- Centre for Cardiovascular Research, Griffith University Gold Coast Campus, Southport QLD 4217, Australia
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Abstract
Experiments were designed to evaluate the mechanisms of propofol and adenosine in rat atrial muscle. Atria were suspended in the isolated organ bath system for isometric tension recording and response to propofol and adenosine were tested in the absence and presence of glibenclamide, N(G)-nitro-arginine-methyl-ester (l-NAME), tetraethylammonium (TEA) and 8-phenyltheophylline (8-PT). The inotropic effect of propofol was elicited by TEA and glibenclamide. In contrast, l-NAME and 8-PT has no effect on the propofol-induced inhibition of atria. Furthermore, atria exhibited a diminished sensitivity to the adenosine-induced negative inotropic effect in the presence of the K(ATP)channel inhibitor glibenclamide, but not the non-specific K(+)channel inhibitor TEA. The adenosine A(1)receptor antagonist 8-PT decreased the responsiveness of adenosine-induced inhibition of atrial muscle. We propose that propofol-induced inotropy is generally mediated by K(+)channels, whereas adenosine-induced inotropy is partially mediated by K(+)channels. Both propofol- and adenosine-induced inotropy were not mediated by nitric oxide release. Our study provides further evidence that there was no contribution of adenosine in the propofol-induced inotropy.
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Affiliation(s)
- I Cinel
- Department of Anesthesiology and Reanimation, Faculty of Medicine, Mersin University, Mersin, Turkey
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Shan HQ, Cheng JS. Effect of adenosine on adenosine triphosphate-sensitive potassium channel during hypoxia in rat hippocampal neurons. Neurosci Lett 2000; 286:45-8. [PMID: 10822149 DOI: 10.1016/s0304-3940(00)01083-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Using the whole-cell patch clamp method, we explored the effect of adenosine on the K(ATP) current and its regulatory mechanisms in acutely dissociated rat hippocampal neurons. A chemical hypoxia model was made using 0.2 mmol/l 2,4dinitrophenol (2,4DNP). During hypoxia, the K(ATP) current was not raised significantly by adenosine alone, but was accelerated significantly by adenosine in combination with the selective A(2) receptor blocker 3, 7-dimethl-1-propargylxanth-ine. The selective A(1) receptor agonist N6-cyclopentyladenosine also accelerated the K(ATP) current. These results suggest that activation of the adenosine A(1) receptor can accelerate opening of the K(ATP) channel during hypoxia, and that the A(2) receptor may have an opposing effect to the A(1) receptor.
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Affiliation(s)
- H Q Shan
- National Laboratory of Medical Neurobiology, Department of Neurobiology, Shanghai Medical University, 138 YiXueYuan Road, 200032, People's Republic of, Shanghai, China.
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Abstract
Prolonged reversible postischemic contractile dysfunction that follows single or multiple brief periods of regional or global ischemia has been termed "stunned myocardium," and is thought to be the result of a decreased responsiveness of the cardiac myofilaments to calcium. A number of hypotheses have been proposed to explain the pathogenesis of stunned myocardium; however, the two major theories that are supported by the most experimental evidence suggest that the generation of oxygen-derived free radicals and a disturbance in calcium homeostasis are responsible for the postischemic contractile dysfunction observed. These mechanisms are not mutually exclusive, and data are available that support both theories. Evidence exists that indicates that one may pharmacologically enhance the recovery of stunned myocardium by use of oxygen radical scavengers, adenosine agonists, calcium channel blockers, and openers of the ATP-sensitive potassium channel, including the volatile anesthetic isoflurane. Ischemic preconditioning (IPC) has also been shown to produce delayed protection against myocardial stunning, and a novel pharmacological agent, monophosphoryl lipid A, has been shown to mimic the effect of IPC. Because stunning appears to occur in a number of clinical settings, it is important to understand the mechanisms involved and to develop pharmacological therapy that will result in an improved clinical outcome.
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Affiliation(s)
- G J Gross
- Department of Pharmacology, Medical College of Wisconsin, Milwaukee 53226, USA.
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Thourani VH, Nakamura M, Ronson RS, Jordan JE, Zhao ZQ, Levy JH, Szlam F, Guyton RA, Vinten-Johansen J. Adenosine A(3)-receptor stimulation attenuates postischemic dysfunction through K(ATP) channels. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:H228-35. [PMID: 10409201 DOI: 10.1152/ajpheart.1999.277.1.h228] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We tested the hypothesis that selective adenosine A(3)-receptor stimulation reduces postischemic contractile dysfunction through activation of ATP-sensitive potassium (K(ATP)) channels. Isolated, buffer-perfused rat hearts (n = 8/group) were not drug pretreated (control) or were pretreated with adenosine (20 microM), 2-chloro-N(6)-(3-iodobenzyl)-adenosine-5'-N-methyluronamide (Cl-IB-MECA; A(3) agonist, 100 nM), Cl-IB-MECA + 8-(3-noradamantyl)-1,3-dipropylxanthine (KW-3902; A(1) antagonist, 5 microM), Cl-IB-MECA + glibenclamide (Glib; K(ATP)-channel blocker, 0. 3 microM), or Glib alone for 12 min before 30 min of global normothermic ischemia followed by 2 h of reperfusion. After 2 h of reperfusion, left ventricular developed pressure (LVDP, %baseline) in control hearts was depressed to 34 +/- 2%. In hearts pretreated with Cl-IB-MECA, there was a statistically significant increase in LVDP (50 +/- 6%), which was reversed with coadministration of Glib (37 +/- 1%). Control hearts also showed similar decreases in left ventricular peak positive rate of change in pressure (dP/dt). Therefore, the A(3) agonist significantly attenuated postischemic cardiodynamic injury compared with the control, which was reversed by Glib. Cumulative creatine kinase (CK in U/min) activity was most pronounced in the control group (10.4 +/- 0.6) and was significantly decreased by Cl-IB-MECA (7.5 +/- 0.4), which was reversed by coadministration of Glib (9.4 +/- 0.2). Coronary flow was increased during adenosine infusion (160% of baseline) but not during Cl-IB-MECA infusion. Effects of Cl-IB-MECA were not reversed by the specific A(1) antagonist KW-3902. We conclude that cardioprotection afforded by A(3)-receptor stimulation may be mediated in part by K(ATP) channels. Cl-IB-MECA may be an effective pretreatment agent that attenuates postischemic cardiodynamic dysfunction and CK release without the vasodilator liability of other adenosine agonists.
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Affiliation(s)
- V H Thourani
- Division of Cardiothoracic Surgery, Department of Surgery, Crawford Long Hospital, Atlanta, Georgia 30365-2225, USA
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Cargnoni A, Ceconi C, Boraso A, Bernocchi P, Monopoli A, Curello S, Ferrari R. Role of A2A receptor in the modulation of myocardial reperfusion damage. J Cardiovasc Pharmacol 1999; 33:883-93. [PMID: 10367591 DOI: 10.1097/00005344-199906000-00008] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Adenosine protects myocardium from ischemia and reperfusion damage; however, the mechanism of action is still under discussion. We investigated whether (a) adenosine protects isolated crystalloid-perfused rabbit heart from ischemia/ reperfusion injury; (b) this action is receptor mediated and what receptor subtypes are involved, and (c) this action is dependent on an enhanced nitric oxide production. Our results showed a cardioprotective effect of adenosine (10(-4) M), of nonselective adenosine-receptor agonist 5'-N-ethyl-carboxamidoadenosine (NECA; 5 x 10(-6) M), and of A2A agonists CGS 21680 (10(-8) and 10(-6) M), 2-hexynylNECA (10(-7) M). On the contrary, A1 agonist CCPA (10(-8) and 10(-6) M) does not provide any protection. The effect has been achieved in terms of significant reduction in contracture development during reperfusion [diastolic pressure was 46.8 +/- 7.1 mm Hg (p < 0.01); 46.1 +/- 7.8 mm Hg (p < 0.01); 46.9 +/- 5.5 mm Hg (p < 0.01); and 59.3 +/- 6.7 mm Hg (p < 0.05) with 10(-4) M adenosine, 5 x 10(-6) M NECA, 10(-6) M CGS 21680, and 10(-7) M 2-hexynylNECA, respectively, versus 77.6 +/- 5.0 mm Hg in control]; reduced creatine phosphokinase release (13.5 +/- 1.6, 22.2 +/- 7.9, 14.2 +/- 3.3, and 14.1 +/- 4.5 U/gww in treated hearts vs. 34.6 +/- 7.2 U/gww in controls; p < 0.05); improved energy metabolism [adenosine triphosphate (ATP) content is 9.9 +/- 0.5, 10.4 +/- 0.6, 9.8 +/- 0.5, and 10.5 +/- 0.5 micromol/gdw in treated hearts vs. 7.6 +/- 0.2 micromol/gdw; p < 0.05]. Moreover, our data indirectly show a functional presence of A2A receptors on cardiomyocytes as the protection is A2A mediated and exerted only during reperfusion, although in the absence of blood and coronary flow changes. These activities appear independent of nitric oxide pathways, as adenosine and 2-hexynylNECA effects are not affected by the presence of a nitric oxide-synthase inhibitor (10(-4) M L-NNA).
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Affiliation(s)
- A Cargnoni
- Cardiovascular Research Center, Salvatore Maugeri Foundation, Gussago, Brescia, Italy
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Mentzer RM, Birjiniuk V, Khuri S, Lowe JE, Rahko PS, Weisel RD, Wellons HA, Barker ML, Lasley RD. Adenosine myocardial protection: preliminary results of a phase II clinical trial. Ann Surg 1999; 229:643-9; discussion 649-50. [PMID: 10235522 PMCID: PMC1420808 DOI: 10.1097/00000658-199905000-00006] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To evaluate the safety, tolerance, and efficacy of adenosine in patients undergoing coronary artery bypass surgery. SUMMARY BACKGROUND DATA Inadequate myocardial protection in patients undergoing coronary artery bypass surgery contributes to overall hospital morbidity and mortality. For this reason, new pharmacologic agents are under investigation to protect the regionally and globally ischemic heart. METHODS In a double-blind, placebo-controlled trial, 253 patients were randomized to one of three cohorts. The treatment arms consisted of the intraoperative administration of cold blood cardioplegia, blood cardioplegia containing 500 microM adenosine, and blood cardioplegia containing 2 mM adenosine. Patients receiving adenosine cardioplegia were also given an infusion of adenosine (200 microg/kg/min) 10 minutes before and 15 minutes after removal of the aortic crossclamp. Invasive and noninvasive measurements of ventricular performance were obtained before, during, and after surgery. RESULTS The high-dose adenosine cohort was associated with a trend toward a decrease in high-dose dopamine support and a lower incidence of myocardial infarction. A composite outcome analysis demonstrated that patients who received high-dose adenosine were less likely to experience one of five adverse events: high-dose dopamine use, epinephrine use, insertion of intraaortic balloon pump, myocardial infarction, or death. The operative mortality rate for all patients studied was 3.6% (9/253). CONCLUSIONS Adenosine treatment is safe and well tolerated and may be associated with fewer postoperative complications.
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Affiliation(s)
- R M Mentzer
- Department of Surgery, University of Kentucky College of Medicine, Lexington 40526-0298, USA
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Lasley RD, Randhawa, Jr. MPS, Hegge JO, Mentzer, Jr. RM. Effects of adenosine and acadesine on interstitial nucleosides and myocardial stunning in the pig. Can J Physiol Pharmacol 1999. [DOI: 10.1139/y99-023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
5-Amino-4-imidazolecarboxamide riboside (AICAr) or acadesine has been proposed to exert cardioprotection by enhancing adenosine production in ischemic myocardium. However, there are conflicting reports on acadesine's effects in ischemic myocardium and few studies in which myocardial adenosine levels have been measured. The purpose of this study was to determine whether acadesine increases interstitial fluid adenosine levels and attenuates myocardial stunning or potentiates the effects of adenosine in the intact pig. In pentobarbital-anesthetized pigs, myocardial stunning was induced by 10 min left anterior descending coronary artery occlusion and 90 min reperfusion. Regional ventricular function was assessed by measuring systolic wall thickening, and interstitial nucleosides were estimated by cardiac microdialysis. Control hearts were compared with hearts treated with acadesine, adenosine, and adenosine plus acadesine. Adenosine pretreatment (100 µg·kg-1·min-1, intracoronary) immediately prior to ischemia increased interstitial adenosine levels 9-fold and improved postischemic functional recovery from a control value of 17.6 ± 4.1% to 43.6 ± 3.4% of preischemic systolic wall thickening. In contrast, acadesine (20 mg/kg i.v. bolus 10 min prior to ischemia + 0.5 mg·kg-1·min-1, i.v. infusion through 60 min reperfusion) had no effect on interstitial fluid adenosine levels or the recovery of regional function (21.5 ± 5.9% recovery), nor were the functional effects of adenosine potentiated by acadesine. These findings indicate that acadesine does not enhance myocardial adenosine levels, attenuate myocardial stunning, or potentiate the cardioprotective effects of adenosine in the pig.Key words: adenosine, acadesine, interstitial fluid, microdialysis, myocardial stunning.
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Chapter 23 Role of KATP Channels in Cardioprotection. CURRENT TOPICS IN MEMBRANES 1999. [DOI: 10.1016/s0070-2161(08)60939-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Kobayashi Y, Goto Y, Daikoku S, Itoh A, Miyazaki S, Ohshima S, Nonogi H, Haze K. Cardioprotective effect of intravenous nicorandil in patients with successful reperfusion for acute myocardial infarction. JAPANESE CIRCULATION JOURNAL 1998; 62:183-9. [PMID: 9583444 DOI: 10.1253/jcj.62.183] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This study was designed to assess the cardioprotective effect of intravenous nicorandil, a potassium channel opener, in preventing reperfusion injury in acute myocardial infarction. Seventy patients were treated with placebo or nicorandil concomitant with reperfusion therapy in a prospective, randomized, double-blind fashion within 6 h after the onset of acute myocardial infarction. Nicorandil was administered before reperfusion as a 2-mg bolus iv injection followed by continuous infusion of 2-6 mg/h for the next 3 h. Thirty-six patients (17 in the placebo group, 19 in the nicorandil group) who demonstrated both complete occlusion of an infarct-related vessel before treatment and successful reperfusion were included in the final analysis. No significant changes in left ventricular ejection fraction were observed between the immediate and chronic phases in each group. In the analysis of regional ventricular function, the placebo group did not show any significant change in regional chord shortening (26.8+/-8.2 vs 24.3+/-7.3%, NS) or hypocontractile perimeter (36.4+/-28.2% vs 28.3+/-24.8%, NS) between immediate and chronic phase left ventriculograms. In contrast, in the nicorandil group, a significant increase in regional chord shortening (21.5+/-11.0% vs 25.8+/-11.3%, p<0.05) and a significant decrease in hypocontractile perimeter (33.3+/-19.6% vs 25.6+/-24.3%, p<0.05) were observed in the chronic phase left ventriculogram. Thus, nicorandil may be a useful adjunctive therapy for preserving myocardial contractile function in patients with acute myocardial infarction undergoing reperfusion therapy.
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Affiliation(s)
- Y Kobayashi
- Department of Medicine, National Cardiovascular Center, Suita, Osaka, Japan
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Jovanović A, Lopez JR, Alekseev AE, Shen WK, Terzic A. Adenosine prevents K+-induced Ca2+ loading: insight into cardioprotection during cardioplegia. Ann Thorac Surg 1998; 65:586-91. [PMID: 9485282 DOI: 10.1016/s0003-4975(97)01240-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In clinical practice, hyperkalemic cardioplegia induces sarcolemmic depolarization, and therefore is used to arrest the heart during open heart operations. However, the elevated concentration of K+ that is present in cardioplegic solutions promotes intracellular Ca2+ loading, which could aggravate ventricular dysfunction after cardiac operations. This review highlights recent findings that have established, at the single cell level, the protective action of adenosine against hyperkalemia-induced Ca2+ loading. When it was added to hyperkalemic cardioplegic solutions, adenosine, at millimolar concentrations and through a direct action on ventricular cardiomyocytes, prevented K+-induced Ca2+ loading. This action of adenosine required the activation of protein kinase C, and it was effective only in cardiomyocytes with low diastolic Ca2+ levels. Of importance, adenosine did not diminish the magnitude of K+-induced membrane depolarization, allowing unimpeded cardiac arrest. Taken together, these findings provide direct support for the idea that adenosine is valuable when used as an adjunct to hyperkalemic cardioplegia. This idea has emerged from previous clinical studies that have shown improvement of the clinical outcome after cardiac operations when adenosine or related substances were used to supplement cardioplegic solutions. Further studies are required to define more precisely the mechanism of action of adenosine, and the conditions that may determine the efficacy of adenosine as a cytoprotective supplement to cardioplegia.
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Affiliation(s)
- A Jovanović
- Department of Medicine, Mayo Clinic, Mayo Foundation, Rochester, Minnesota 55905, USA
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