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

Abstract

The role of adenosine matching myocardial O2 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 O2 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 O2 consumption and pericardial adenosine accumulation during 2 levels of treadmill exercise, excitement caused by loud noises, and feeding (the presentation and consumption of a meal). Significant increases in the adenosine production were seen with all experimental procedures and significant linear correlations between myocardial O2 consumption and coronary blood flow (r = 0.78), myocardial O2 consumption and adenosine production (r = 0.73), and adenosine production and coronary blood flow (r = 0.88). Increases in adenosine production by the normally oxygenated myocardium can be the physiological mechanism for matching O2 supply to increased O2 demand in the conscious dog.