Fig. 8

Intracellular calcium ion (Ca²⁺) levels are influenced by electrical stimulation (ES). A Fluo-3 stained cells directly after 2 h ES at different positions in the well. Note that Ca²⁺ levels are dependent on the position in the well. B Schematic view of microscopy positions in the well. Images were taken in the middle and close to the electrode positions. C Mean Ca²⁺ fluorescence at the different positions (mean ± s.e.m., n = 6–7 independent experiments, á 8–30 cells per position, Two-way ANOVA with Bonferroni’s multiple comparison test). D Intracellular Ca²⁺ of Fluo-3 stained cells seeded for 2 h in ES medium vs. medium with 10 μM H₂O₂. Note that Ca²⁺ levels are not influenced. E Mean Ca²⁺ fluorescence of medium mediated ES (mean ± s.e.m., n = 4, RM One-way ANOVA with Bonferroni’s multiple comparison tests, n.s.). F Fluo-3 stained cells after direct ES for 2 h in DMEM with pyruvate at different positions of the wells. G Mean Ca²⁺ fluorescence of ES cells in pyruvate-containing medium at different positions. Note that Ca²⁺ levels only slightly increase at position 1. (mean ± s.e.m., n = 6 independent experiments, á 14–38 cells per position, comparison within the positions with RM Two-way ANOVA with Bonferroni’s multiple comparison test). LSM 780, Carl Zeiss, scale bars = 50 μm