BDNF in the development of the visual system of Xenopus.

To explore the role of BDNF during Xenopus visual system development, the expression of BDNF and TrkB, as well as the effect of BDNF during retinal ganglion cell (RGC) development in culture, was examined. BDNF mRNA was found to be expressed in both the developing eye and tectum, peaking at stage 45/46. The expression of BDNF coincided with RGC expression of full-length trkB transcripts, suggesting a functional role for BDNF. In culture, BDNF significantly increased the number of RGCs. The ability of BDNF to rescue differentiated RGCs that had projected to the tectum, the time course of the effect, and the lack of mitogenic response indicate that this neurotrophin promotes survival. The expression of BDNF and TrkB and the responsiveness of RGCs to BDNF coincide with retinal axon terminal arborization and patterning. Our results indicate that BDNF is a relevant neurotrophin for Xenopus RGC development and suggest that it plays a role during visual system patterning.