Adenosine A₁ and A₃ Receptors: Distinct Cardioprotection

Adenosine is released in large amounts during myocardial ischemia and exerts potent cardioprotective effects in the heart. Although these observations on adenosine have been known for a long time, how adenosine acts to achieve its antiischemic effect remains incompletely understood. Recent advances in the chemistry and pharmacology of adenosine receptor ligands have provided important and novel information on the function of adenosine receptor subtypes in the cardiovascular system. The development of model systems for the cardiac actions of adenosine has yielded important insights into its mechanism of action and have begun to elucidate the sequence of signaling events from receptor activation to the actual exertion of its cardioprotective effect. The goal of the current article is to review recent advances on the cellular and molecular mechanisms that mediate the cardiac actions of adenosine and to show the cardioprotective effect of novel adenosine ligands.