Figure 2

Morphological differences of cells cultured for 6 days in differentiation medium after various treatments visualized by Scanning Ion Conductance Microscopy (SICM). (A) Samples of control oligodendrocytes pretreated with proliferation medium alone, (B) proliferation medium supplemented with dexamethasone, (C) proliferation medium supplemented with IFN-γ and TNF-α, (D) proliferation medium supplemented with IFN-γ, TNF-α and dexamethasone. Scans were performed in a frame of 30 × 30 μm with 1 μm lateral step size. Calibration bar converting height into greyscale is shown at the right. (E) Average volume measurements of cell somata (height > 3 μm), calculated from the SICM-data. Note, that the smallest volumes correspond to cells pretreated with TNF-α and IFN-γ only and the reversal by cotreatment with dexamethasone. (F) Capacitances of cells cultured under the same conditions as cells shown in A-D analysed using the whole cell voltage clamp technique. (G) Surface of cell processes with a height of more than 0.5 μm above the culture dish, calculated from the SICM data. (H) Soma surface (height of more than 3.0 μm above the culture dish) calculated from the SICM data. Note, that the TNF-α and IFN-γ treatment and dexamethasone rescue affect predominantly the process surface. Hence most of the capacitance is contributed by the process membrane. Error bars indicate mean ± SE, * p < 0.05, ** p < 0.01, *** p < 0.001. C: control, DC: treatment with dexamethasone, TI: treatment with TNF-α and IFN-γ, TID: cotreatment with TNF-α and IFN-γ plus dexamethasone each for two days in proliferation medium