Adenosine. The signal of life?

In this issue of Circulation,' Hori and colleagues report the results of using three antioxidant agents in an attempt to reduce ischemic injury in a coronary microembolization model. Repeated injections of 15-,um microspheres resulted in progressive microvascular obstruction, decreased function, and edema until the extent of embolization decreased flow to nearly zero (less than 0.08 ml/min/ g). In this model, adenosine release from ischemic regions induces hyperemia in nonobstructed vessels. With successive injections, progressively smaller border zones surround areas of increasing microvascular obstruction until the extent of embolization occludes