Figure 1.

NG2⁺ cells express voltage-gated Na⁺ channels but are inexcitable. a, TTX-sensitive inward currents induced by 70 mV depolarization from a holding potential of −80 mV in a P12 CA1 pyramidal neuron (left) and a P13 callosal NG2⁺ cell (right); illustration of how amplitude of peak NaV current was determined (far right). b, Comparison of NaV current density in NG2⁺ cells in CC, CA1 HC, CB ml, and CB wm at multiple developmental time points; n for each group indicated at the base of the column. NaV channel expression was not significantly altered across development in each brain region (for P5–P8 vs P40–P45, p = 0.60 CC, p = 0.78 HC, p = 0.36 CB wm; for P12–P15 vs P40–P45, p = 0.71 CB ml). c, Response of NG2⁺ cells in mature mice (P40–P45) to depolarizing current injection; for each brain region, two examples are shown; red trace, injection of 160 pA current. Black asterisk highlights responses where the first positive current injection was 500 pA. d, Response of NG2⁺ cells to depolarizing current injection at early developmental time points (P5–P8 CC, HC, CB wm and P12–P15 CB ml); for each brain region two examples are shown; red trace, injection of 160 pA current. Red asterisk highlights response where depolarization triggered a small Na⁺ spike. Black asterisk highlights responses where the largest current injection was 70 pA.