GABA promoted migration of cultured NG2 cells. (A) Images showing migrated cells immunopositive for anti-NG2 staining without (control) or with 1 mM GABA added to the bottom chamber of the transwell (see Materials and methods). Bar, 20 µm. (B) Images showing migration of purified NG2 cells cotransfected with pGFP + siRNA-control or pGFP + siRNA-NCX1 in the presence of 1 mM GABA at the bottom chamber of the transwell. Bar, 20 µm. (C) Summary data showing the GABA-induced migration of purified NG2 cells with or without various inhibitors or siRNA transfections. Data are normalized as the percentage of migrated NG2 cells in control (gray) or GFP-control (white) group (broken line; without GABA in the bottom chamber), respectively. Note that homogeneous GABA (1 mM, added in both top and bottom chambers) did not affect NG2 cell migration. **, P < 0.01 compared with the control or GFP control group, respectively. Error bars represent mean ± SEM.