(A) Microscope view during the intracellular vesicle impact electrochemical cytometry experiment (scale bar = 20 μm). (B) Normalised frequency histogram for the number of molecules stored in vesicles in control (blue) and modafinil-treated cells (red). The distribution fits are shown for control cells with a dashed line and modafinil-treated cells with a solid line. (C) Average of the number of molecules stored per vesicle in PC12 cells treated without (control) or with 10 μM modafinil. Number of analysed cells: control cells (15 cells) and modafinil-treated cells (18 cells). The results were compared by a two-tailed Mann–Whitney rank-sum test, *p < 0.05, **p < 0.01 and ***p < 0.001.