Although extracellular adenosine signaling was initially described to induce a transient slowing of heart rate (69), many subsequent studies have sown functional roles for extracellular adenosine signaling in attenuating myocardial ischemia and reperfusion injury, including studies directly implicating myeloid Adora2b signaling (7, 36, 43) (Figure 7). This evidence concerns the gene ADORA2B and myocardial ischemia.