To address whether human OPCs and oligodendrocytes exhibit conservation of cell‐type specific membrane conductances in response to membrane depolarization 23, 24, 25, we undertook electrophysiological recordings from OPCs and cells colabeled for O4 and MBP. Having already established extremely limited colabeling of PDGFRα and O4 (Fig. 1C, 1E), electrophysiological recordings were undertaken on live‐stained OPCs and differentiated oligodendrocytes using antibodies against PDGFRα and O4 (Fig. 2A). For PDGFRα+‐OPCs at week 1, a depolarizing voltage‐step protocol induced large outward currents that consisted of transient and sustained components (Fig. 2A). In contrast, the application of the same voltage‐step protocol applied to O4+‐oligodendrocytes at week 1 and 3 yielded currents that were substantially lower in amplitude than those observed in OPCs (Fig. 2A). Mean current–voltage (I–V) relationships constructed from this data show that evoked membrane currents in hPSC‐derived OPCs are outwardly rectifying and differentiation to O4+‐oligodendrocytes is associated with a reduced degree of outward rectification (Fig. 2B). Rectification indices were subsequently calculated (see Materials and Methods section) to quantify such rectification shifts and revealed that current rectification was reduced in each line of
