Effects of a N(6)-disubstituted adenosine derivative on myocardial metabolism and ischemic stress following coronary occlusion.

The effect of N(6)-phenyl-N(6)-allyladenosine (PAA, BM 11.189) on myocardial ischemic stress was evaluated in six open-chest mongrel dogs during repeated coronary occlusions of 3 min. Whereas there was not significant change in hemodynamic parameters before and during coronary occlusions after treatment, PAA reduced significantly epicardial ST-segment elevations (-34%) during ischemia and myocardial release of lactate (-43%), phosphate (-44%), and potassium (-48%) in the early reperfusion period. PAA lowered significantly arterial non esterified fatty acids and converted oxidative myocardial metabolism from lipid to predominantly carbohydrate utilization, reflected by a shift of cardiac respiratory quotient from 0.81 to 1.01. The beneficial effects of PAA on myocardial ischemic injury could be explained by an improved economy of oxidative myocardial energy supply in the jeopardized border zone of the ischemic myocardium.