Adenosine and coronary blood flow in conscious dogs during normal physiological stimuli

The role of adenosine in matching myocardial oxygen supply to demand by regulating coronary blood flow has been the subject of intensive study. The present experiments were designed to determine the relationship among myocardial oxygen consumption, coronary blood flow, and adenosine production as estimated by pericardial adenosine accumulation under several physiological conditions in the same animal. Conscious chronically instrumented dogs were used to measure changes in coronary blood flow, myocardial oxygen consumption, and pericardial adenosine accumulation during two levels of treadmill exercise, excitement caused by loud noises, and feeding (the presentation and consumption of a meal). The results show significant increases in the adenosine production with all experimental procedures and significant linear correlations between myocardial oxygen consumption and coronary blood flow (r = 0.78), myocardial oxygen consumption and adenosine production (r = 0.73), and adenosine production and coronary blood flow (r = 0.88). These data show that increases in adenosine production by the normally oxygenated myocardium can be the physiological mechanism for matching oxygen supply to increased oxygen demand in the conscious dog.