EFFECTS OF L-CARNITINE ON MECHANICAL RECOVERY OF ISOLATED RAT HEARTS IN RELATION TO THE PERFUSION WITH GLUCOSE AND PALMITATE

The purpose of this study was to investigate the effects of L-carnitin e on the hemodynamic parameters of Langendorff hearts. Isolated rat he arts were perfused with various solutions containing high or low conce ntrations of fatty acids, additional glucose or no glucose, and L-carn itine or no L-carnitine. The most interesting part of the experiments was the behaviour of the hearts in the reperfusion period after no-flo w ischemia of 20 min. The results were: (1) With glucose and high fatt y acid concentrations the hearts showed an improved recovery of the le ft ventricular functions in the reperfusion period compared with low f atty acid concentrations. Without glucose the left ventricular pressur e is much lower in the reperfusion period. (2) Addition of L-carnitine improved the recovery of the ischemically damaged hearts. This improv ement is especially impressive at low fatty acid concentrations. L-car nitine addition at high fatty acid concentrations but without glucose strongly improved reperfusion behaviour. (3) The coronary flow is incr eased by 2 experimental conditions: (i) perfusion at low levels of fat ty acids, carnitine and with glucose and (ii) high levels of fatty aci ds and carnitine but without glucose. These findings suggest that supp lementation of L-carnitine has a beneficial effect on the isolated hea rt under various conditions, and possibly on specific human heart dise ases.