Myocardial Adenosine Receptors
Currently there are four well-defined subclasses of adenosine receptors, namely, A1, A2a, A2b, and A3. In the heart, A1 receptor pharmacology, regulation, and coupling to functional responses have been well characterized. The presence of an A2 receptor that mediates adenosine-induced coronary vasodilation is also well established, although the receptor subtype (A2a vs. A2b) is still the subject of some debate. The A2 receptor and its role in adenosine-mediated coronary vasodilation are reviewed in Chapter 27. Although the results of several studies provide support for the presence of an A3 receptor in the heart, a physiologic role for the cardiac A3 receptor has yet to be determined. Thus, the primary focus of this review will be the cardiac A1 adenosine receptor; however physical or functional evidence for the presence of other receptor subtypes on cardiomyocytes will be presented.
KeywordsAdenosine Receptor Ventricular Myocytes Adenosine Receptor Subtype Allosteric Enhancer Guanine Nucleotide Regulatory Binding Protein
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