GABA-induced [Na⁺]_i elevation in cultured NG2 cells. (A) Confocal images of cultured NG2 cells preloaded with the Na⁺ dye SBFI/AM. Images were taken from the same imaging field before (control) and during perfusion with 1 mM GABA. Bar, 25 µm. (B) Averaged data showing the time course of [Na⁺]_i changes in cultured NG2 cells under control or perfusion with GABA with or without 1 µM TTX. (C) Summary of GABA- and muscimol-induced [Na⁺]_i changes in NG2 cells in the presence or absence (control) of various inhibitors. Data were averaged during 3–5 min after the onset of perfusion with 1 mM GABA or 50 µM muscimol, and normalized by the mean fluorescence intensity obtained during the control period (0–5 min before perfusion with GABA or muscimol) for each cell. *, P < 0.05; **, P < 0.01 compared with the control group or between groups indicated. Error bars represent mean ± SEM.