Figure 3.

PGSF inhibits glutamate-induced Ca²⁺ overload in cultured hippocampal neurons.

Cells were incubated for 4 hours with glutamate (100 µM) alone or in the presence of PGSF (10 µM) or MK801 (10 µM), or under Ca²⁺-free conditions. Intracellular concentrations of Ca²⁺ were visualized by staining with Fluo-4 AM. (A–E) Representative images of neurons under the different experimental conditions. Compared with the neurons in the other groups, fluorescence intensity was markedly stronger in the neurons treated with glutamate alone. Scale bar: 50 µm. (F) Quantitative analysis of the relative fluorescence intensity of neurons under the different experimental conditions. Data are shown as the mean ± SEM. The experiment was repeated four times. **P < 0.01 (one-way analysis of variance followed by Dunnett’s post hoc test). Original data for Figure 3 are shown in Additional file 4. AU: Arbitrary unit; Glu: glutamate; MK801: (5S,10R)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate, an N-methyl-D-aspartate receptor antagonist; PGSF: polygalasaponin F.