Figure 1).

Experimental protocol: All pigs underwent 60 min occlusion of the left anterior descending coronary artery. Ischemic preconditioning (PC) was elicited with 5 min of occlusion followed by 5 min of reperfusion. Saline (control) or N-2-mercaptopropionyl glycine (MPG, 20 mg/kg) was infused over 40 min until the initiation of sustained ischemia. Phosphocreatine, ATP and intracellular pH were serially measured using 31-phosphorus nuclear magnetic resonance (NMR) spectroscopy. The arrows indicate the administration of coloured microspheres for determining regional myocardial blood flow (RMBF)