THE FACILITATING EFFECT OF GANGLIOSIDES ON THE ELECTROGENIC (NA+/K+) PUMP AND ON THE RESISTANCE OF THE MEMBRANE-POTENTIAL TO HYPOXIA IN NEUROMUSCULAR PREPARATION

The effects have been investigated of a mixture of gangliosides from beef brain cortex (GM1, GD(1a), GD(1b) ang GT1) either added to the bathing medium or injected intraperitoneally on muscle fibres and nerve terminals in mouse diaphragm. The electrogenic (Na+/K+) pump activity of muscle fibres enriched with sodium was increased by 38% after 2-h pretreatment with gangliosides (5 x 10-8 mol.l-1). Muscles from animals treated with gangliosides did not show the substantial depolarization of the resting membrane potential (RMP) in K+-free solution (6 h) shown by control muscles. Further, treatment with gangliosides slowed the changes in muscle fibre RMP and frequency of the miniature end-plate potentials in oxygen deprived muscles.