Figure 8.

NG2⁺ cells in the adult corpus callosum express Ca²⁺-permeable AMPARs. (a) Evoked EPSCs recorded from an NG2⁺ cell in the developing corpus callosum (P8) with an internal solution containing spermine (left traces) at holding potentials of −90, −50, −10 and 30 mV. At right is the current-voltage (I-V) relationship of AMPAR currents elicited in NG2⁺ cells in young animals (P7–P8) (n = 4). These responses showed little rectification, indicating that few Ca²⁺-permeable AMPARs were activated. (b) Evoked EPSCs recorded from an NG2⁺ cell in the mature corpus callosum (P52) with an internal solution containing spermine (left traces) at holding potentials of −90, −50, −10 and 30 mV. At right is the I-V relationship of AMPAR currents elicited in NG2⁺ cells in mature animals (P42–P52), when spermine was present (filled circles, n = 8)) or absent (open circles, n = 3) from the internal solution. Responses at this age showed prominent inward rectification, indicating that Ca²⁺-permeable AMPARs contributed to the EPSCs.