Figure 5.

K⁺ currents induced by neuronal activity in OPCs of 4–5PN weeks are mediated by Kir4.1 channels. A, B, Effect of 100 μm Ba²⁺ on inward currents resistant to antagonists and evoked by paired-pulse stimulation of neuronal fibers in OPCs held at −70 mV and recorded in CsCl-based intracellular solution (A) and KCl-based intracellular solution (B). Stimulus artifacts were blanked for visibility. A vertical line indicates the time of stimulation. Pulses were separated by 50 ms in all cases (100 μs, 40 V). C, Inward currents evoked in two OPCs recorded with an intracellular solution at a pH of 7.4 (left) and of 6.3 (right) in the same slice and with the same stimulation electrode as shown in the diagram (left).