Figure 4.

Activation of astrocytes by CNTF increases myelination. Myelinating cultures were plated onto PLL-As (black bars) or TnC-As (gray bars). CNTF treatment increased myelination in all cultures. When TnC-As were used to condition cultures plated on PLL-As, myelination was not affected, suggesting that the TnC effect is overcome by PLL-As. Conversely, cultures plated on TnC-As conditioned by coverslips of PLL-As promoted myelination. PLL-As pretreated with CNTF, washed, and then added to cultures resulted in an increase in myelination, suggesting the CNTF activates the astrocyte directly (*p < 0.05; ns, p > 0.05).