GANGLIOSIDES RAISE THE INTRACELLULAR CA2+ LEVEL IN DIFFERENT CELL-TYPES

Total gangliosides from bovine brain at micromolar concentration induce intracellular Ca2+ increments in a temperature, time and dose dependent manner when assayed with suspensions of rat macrophages, rat and chicken neurons, human erythrocytes and liposomes, loaded with the fluorescent Ca2+ indicator FURA 2. The effect was independent on the endogenous ganglioside composition of the cells and in the case of neurons it was also independent on the differentiation state. Gangliosides do not induce the release of Ca2+ from inner stores. These findings indicate that the reported inhibition of arachidonic acid release (Bressler, J., et al., (1994) Life Sci., 54, 49-60) and anti-inflammatory properties of gangliosides (Correa, S.G. et al., (1991) fur. J. Pharmacol. 199, 93-98) are not due to impairments of Ca2+ nux. The results also suggest the possibility that the well-known neurotrophic effect produced by gangliosides on undifferentiated neurons in culture may be due to subtoxic cytosolic Ca2+ increments.