Fig. 6. Increased expression of p75 after PSA removal. (A) Real-time RT-PCR analysis of p75, TrkB and TrkC mRNA after Endo-N treatment. RNA extracted from SVZ-derived neurons treated either with Endo-N (black bars) or with vehicle (white bars) were used to quantify the expression of p75, TrkB and TrkC in three independent experiments. Compared with vehicle-treated cultures, removal of PSA specifically affected p75 levels. ^*, P<0.05 (two-tailed unpaired t-test). (B) Confocal photomicrographs of ßIII-tubulin (green) and p75 (red) double-labeling in neurons treated with vehicle or with Endo-N demonstrate the upregulation of p75 expression in cells lacking PSA. (C) Quantification of p75 immunoreactivity using confocal microscopy. Cells treated with Endo-N for 20 hours showed a significant increase in p75 immunoreactivity compared with controls. Scale bar: 20 µm.