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8346634 
Journal Article 
Adenosine, adenosine receptors and myocardial protection: An updated overview 
Mubagwa, K; Flameng, W 
2001 
Yes 
Cardiovascular Research
ISSN: 0008-6363
EISSN: 1755-3245 
52 
1 
25-39 
English 
Adenosine (Ado) accumulates in tissues under metabolic stress. On myocardial cells, the nucleoside interacts with various receptor subtypes (A1, A3, and probably A2A and A2B) that are coupled, via G proteins, to multiple effectors, including enzymes, channels, transporters and cytoskeletal components. Studies using Ado receptor agonists and antagonists, as well as animals overexpressing the A1 receptor indicate that Ado exerts anti-ischemic action. Ado released during preconditioning (PC) by short periods of ischemia followed by reperfusion induces cardioprotection to a subsequent sustained ischemia. This protective action is mediated by A1 and A3 receptor subtypes and involves the activation and translocation of PKC to sarcolemmal and to mitochondrial membranes. PKC activation leads to an increased opening of ATP-sensitive K+ (KATP) channels. Recent studies implicate mitochondrial rather than sarcolemmal KATP channels in the protective action of PC. Other effectors possibly contributing to cardioprotection by Ado or PC, and which seem particularly involved in the delayed (second window of) protection, include MAP kinases, heat shock proteins and iNOS. Because of its anti-ischemic effects, Ado has been tested as a protective agent in clinical interventions such as PTCA, CABG and tissue preservation, and was found in most cases to enhance the post-ischemic recovery of function. The mechanisms underlying the role of Ado and of mitochondrial function in PC are not completely clear, and uncertainties remain concerning the role played by newly identified potential effectors such as free radicals, the sarcoplasmic reticulum, etc. In addition, more studies are needed to clarify the signalling mechanisms by which A3 receptor activation or overexpression may promote apoptosis and cellular injury, as reported by a few recent studies. © 2001 Elsevier Science B.V. All rights reserved. 
Adenosine; Ion channels; Ischemia; Preconditioning; Receptors; Signal transduction