FIGURE 2.

Characterization of cell types identified among differentiated neural stem/progenitor cells. We identified three distinct cell types in the in vitro cultures, and supplemented them with illustrative images. Cells with a passive current pattern (A) were considered astrocytes as they were mostly GFAP-positive. They displayed predominantly time- and voltage-independent K⁺ currents, together with small amplitudes of delayed outwardly rectifying K⁺ currents (K_DR) and inwardly rectifying K⁺ currents (K_IR). Cells displaying a complex current profile and expressing mainly PDGFRα (B) were considered precursor cells. They expressed fast activating and inactivating outwardly rectifying K⁺ currents (K_A), K_DR, and K_IR currents. Doublecortin (DCX)-positive cells with an outwardly rectifying current pattern (C) were considered neuron-like cells, or neuroblasts, and expressed K_A and K_DR currents. Current patterns were obtained by hyper- and depolarizing the cell membrane from the holding potential of –70 mV to the values ranging from –160 to 40 mV in 10 mV increments (see the inset). DAPI, 4′,6-diamidino-2-phenylindole; GFAP, glial fibrillary acidic protein; PDGFRα, platelet-derived growth factor receptor alpha.