Fig. 6.

OligoGM1-modulated Ca²⁺ derives from both the extracellular environment and the intracellular storages. Intracellular Ca²⁺ level of N2a cells treated with OligoGM1 was analysed measuring the green fluorescent emission of Fluo-4 (2.5 µM). The frames were acquired every 5 sec for 20 min with Widefields Zeiss Axio Observer.Z1 with a 400X magnification. The IP3 receptor inhibitor, Xestospongin C (2.5 µM) was added to the cells together with Fluo-4 for 30 min before starting the acquisitions and left for the entire duration of the experiment. After 3 min of basal acquisition, OligoGM1 (50 µM) was administered to the cells and after 15 min the calcium ionophore A23187 (2 µM) was added. Control cells were loaded with HBSS⁺ alone. Only ionophore responsive cells were analysed. The fluorescence of each frame (Fx) was related to the fluorescence of the basal condition (F0) (Fx-F0/F0). Results are expressed as the mean ± SEM of fluorescence intensity of at least three independent experiments (OligoGM1 *p < 0.05 vs. basal, one-way ANOVA, n = 11; OligoGM1 **p < 0.01 vs. CTRL, two-way ANOVA; OligoGM1 + Xestospongin C *p < 0.05 vs. basal, one-way ANOVA, n = 5; OligoGM1 + Xestospongin C NS vs. CTRL, two-way ANOVA)