Fig. 3.

Ig-NRG is not a survival factor for granule cells. A, Granule cells in minimal medium were treated with 1 nm Ig-NRG, 5 nm Ig-NRG, 20 ng/ml BDNF, or vehicle (control) for 2 d. Cell survival was then measured by the MTT assay, and the reaction product was analyzed spectrophotometrically. The graph shows an average OD for four independent experiments. Cell survival was significantly increased only by BDNF treatment (BDNF, *p < 0.0001; 1 nm NRG, p = 0.10; 5 nm NRG,p = 0.15). B, Granule cells were treated with 1 nm Ig-NRG, 5 nm Ig-NRG, 20 ng/ml BDNF, or vehicle (control) for 24 hr. Cells were then fixed and stained with Hoechst dye, and the percentage of apoptotic cells was quantified. BDNF but not Ig-NRG treatment significantly reduced the percent of apoptotic cells compared with control (BDNF, *p = 0.014; 1 nm Ig-NRG, p = 0.71; 5 nm Ig-NRG, p = 0.93).