Fig. 5.

Neurotrophic regulation of RGC soma area. To determine whether retinal neurotrophins modulate aspects of RGC morphology in addition to dendritic arborization, we measured the soma area of RGCs in retinae treated with experimentally altered neurotrophin levels. The soma area of RGCs coincident with control-, BDNF-, or anti-BDNF-treated microspheres as well as RGCs not coincident (NC) with BDNF-coated microspheres were compared and found not to differ significantly from control (A). Similarly, the effects of NGF, NT-3, and NT-4 on soma size also were compared (B). BDNF and NGF did not alter soma size, but NT-3-treated RGCs had significantly smaller soma and NT-4-treated RGCs had significantly larger soma than control-treated RGCs, indicating that NT-3 and NT-4 exert opposing influences on soma size. Plotted values represent the averages from five independent experiments; error bars indicate ± SEM. Numbers within the bars indicate the total number (n) of RGCs analyzed for each treatment. ***p < 0.001 and *p< 0.05 as compared with control.