Cardioprotection induced by adenosine A1 receptor agonists in a cardiac cell ischemia model involves cooperative activation of adenosine A2A and A2B receptors by endogenous adenosine

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Title Cardioprotection induced by adenosine A1 receptor agonists in a cardiac cell ischemia model involves cooperative activation of adenosine A2A and A2B receptors by endogenous adenosine
Author Urmaliya, Vijay B.; Church, Jarrod E.; Coupar, Ian M.; Rose'Meyer, Roselyn Barbara; Pouton, Colin W.; White, Paul J.
Journal Name Journal of Cardiovascular Pharmacology
Editor Michael R Rosen
Year Published 2009
Place of publication United States
Publisher Lippincott Williams & Wilkins
Abstract Extracellular adenosine concentrations increase within the heart during ischemia, and any exogenous adenosine receptor agonists therefore work in the context of significant local agonist concentrations. We evaluated the interactions between A1, A2A, A2B, and A3 receptors in the presence and absence of adenosine deaminase (ADA, which is used to remove endogenous adenosine) in a cardiac cell ischemia model. Simulated ischemia (SI) was induced by incubating H9c2(2-1) cells in SI medium for 12 hours in 100% N2 gas before assessment of necrosis using propidium iodide (5 μM) or apoptosis using AnnexinV-PE flow cytometry. N6-Cyclopentyladenosine (CPA; 10-7M) and N6-(3-iodobenzyl) adenosine-5′-N-methyluronamide (IB-MECA; 10-7M) reduced the proportion of nonviable cells to 30.87 ± 2.49% and 35.18 ± 10.30%, respectively (% of SI group). In the presence of ADA, the protective effect of CPA was reduced (62.82 ± 3.52% nonviable), whereas the efficacy of IB-MECA was unchanged (35.81 ± 3.84% nonviable; P < 0.05, n = 3-5, SI vs. SI + ADA). The protective effects of CPA and IB-MECA were abrogated in the presence of their respective antagonists DPCPX (8-cyclopentyl-1,3-dipropylxanthine) and MRS1191 [3-ethyl-5-benzyl-2-methyl-4-phenylethynyl-6-phenyl-1,4-(±)-dihydropyridine-3,5-dicarboxylate], whereas A2A and A2B agonists had no significant effect. CPA-mediated protection was abrogated in the presence of both A2A (ZM241385, 4-(2-[7-amino-2-(2-furyl)[1,2,4]triazolo[2,3-a][1,3,5]triazin-5-lamino]ethyl)phenol; 50 nM) and A2B (MRS1754, 8-[4-[((4-cyanophenyl)carbamoylmethyl)oxy]phenyl]-1,3-di(n-propyl)xanthine; 200 nM) antagonists (n = 3-5, P < 0.05). In the absence of endogenous adenosine, significant protection was observed with CPA in presence of CGS21680 (4-[2-[[6-amino-9-(N-ethyl-b-d-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl]benzenepropanoic acid) or LUF5834 [2-amino-4-(4-hydroxyphenyl)-6-(1H-imidazol-2-ylmethylsulfanyl)pyridine-3,5-dicarbonitrile] (P < 0.05 vs. SI + ADA + CPA). Apoptosis (14.35 ± 0.15% of cells in SI + ADA group; P < 0.05 vs. control) was not significantly reduced by CPA or IB-MECA. In conclusion, endogenous adenosine makes a significant contribution to A1 agonist-mediated prevention of necrosis in this SI model by cooperative interactions with both A2A and A2B receptors but does not play a role in A3 agonist-mediated protection.
Peer Reviewed Yes
Published Yes
Publisher URI http://journals.lww.com/cardiovascularpharm/pages/default.aspx
Alternative URI http://dx.doi.org/10.1097/FJC.0b013e3181a443e2
Volume 53
Issue Number 5
Page from 424
Page to 433
ISSN 0160-2446
Date Accessioned 2010-02-24
Date Available 2010-05-21T06:37:08Z
Language en_AU
Research Centre Griffith Health Institute; Heart Foundation Research Centre
Faculty Griffith Health Faculty
Subject Basic Pharmacology
URI http://hdl.handle.net/10072/29784
Publication Type Journal Articles (Refereed Article)
Publication Type Code c1

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