We measured with the microdialysis technique energy-related metabolites in ischemic myocardium over time in an experimental pig model. Emphasis was put on the dipyridamole effect when administered in the microdialysis probe inserted in ischemic myocardium. Not only adenosine but also taurine and pyruvate concentrations were significantly higher in the microdialysate during the periods of ischemia and extracorporeal circulation with cardioplegia. The enhanced efflux of taurine in ischemic myocardium induced by dipyridamole is a new finding. A mechanistic role of taurine in the prevention of Ca(2+) overload in ischemic myocytes is discussed. Also, taurine may have stimulatory effects on glycolysis in ischemic heart.