Effects of GM1 ganglioside on cardiac function following experimental hypoxia-reoxygenation

Rat hearts made hypoxic for 20 min by perfusion with 95% N2/5% CO2 and reoxygenated for 20 min in a Langerdorff apparatus showed a dose-dependent reduction of lactate dehydrogenase release when incubated with ganglioside GM1 (0.1-10 microM). The decline of contractile force during hypoxia was also reduced dose dependently in the presence of GM1. Similar effects were observed in hearts obtained from animals treated i.p. with 40 mg/kg GM1 for 14 days. The levels of Na+,K(+)-ATPase in ventricular tissue were also reduced after hypoxia-reoxygenation and the reduction was prevented in hearts from GM1-treated animals. GM1 (1-30 microM) reduced the functional response to field stimulation of adrenergic nerve terminals in isolated atria. Rat atria made hypoxic in glucose-free media maintained normal stores of tissue noradrenaline in the presence of 1 microM GM1. In the rabbit, GM1 (40 mg/kg i.p. for 4 days) reduced the alterations of the ST segment of the ECG during acute occlusion of the left descending and circumflex coronaries artery. In conclusion, ganglioside GM1 reduces some effects of hypoxia-reoxygenation in the heart, through still unknown mechanisms.