Figure 6 . Enhancement of neurite outgrowth produced by CP11 treatment is TrkB-independent. A. Distributions of neurite lengths of cultured DRG neurons without treatments (Media) and after treatments with CP11 or 7,8-DHF in the presence or absence of the TrkB inhibitor, ANA-12 are displayed as violin plots. The solid white lines in each violin mark their medians. The horizontal dashed line running through the figure marks the median neurite length from the control group (Media). Numbers above brackets indicate p values associated with statistical comparisons between groups. B. Image of two β3 tubulin-immunoreactive DRG neurons (red) in a culture treated for 24 hours with CP11. Cultures also were reacted with an antibody to the extracellular domain of the TrkB receptor, and a green fluorescing secondary antibody. The lower cell in the image was scored as TrkB+ and the upper cell as TrkB-. C. Cumulative frequency distributions of neurite lengths in cultured adult DRG neurons identified as TrkB+ (top) and TrkB- (bottom) in control (Media) cultures and in cultures treated with either CP11 or 7,8-DHF. Neurite lengths in cultures from different mice were scaled to the median neurite length in the corresponding control (Media only) group. Each cumulative histogram represents the average of the distributions of these scaled neurite lengths from cultures of DRG neurons from six mice. Medians for each group are represented by the projection of the dashed line at the 50th percentile to the horizontal. D. Average (+SEM) median scaled neurite lengths from the same cultures are shown for TrkB+ (top) and TrkB- (bottom) neurons. Numbers above brackets are p values resulting from statistical comparisons made between groups.