Myocardial adenine nucleotides after infusion of adenosine.

In the rabbit heart, continuous infusion (12 ml/hr) of 1% adenosine into the superior caval vein, or of 0.5% adenosine into the left myocardial ventricle, for a period of 3 hr increased the myocardial tissue level of ATP by almost 40% over the control (5.0 mumol/g). Both shorter or longer periods of application and lower or higher concentrations of adenosine, as well as the infusion of adenosine into the left atrium, were less effective. The increase markedly outlasted the period of application of adenosine. It did not result from the adenosine-induced systemic hypotension and decrease in cardiac work, but must be attributed to a direct metabolic effect of the adenosine infusion.