Figure 2.

Ephrins promote growth and branching and induce fragmentation of the medial hippocampal axons. Medial hippocampal neurons from E18 rat embryos were dissected and cocultured for 96 hr. (a and b) Medial hippocampal neurons cocultured with control or ephrin-A5-expressing cells. Neurons were detected with anti-NSE antibody. The neurons grew long and thick axons on the control cells (a), but only very short neurites on the ephrin-A5-expressing cells (b). (c and d) Medial hippocampal neurons cultured on control and ephrin-A5 cells, respectively, and stained with anti-tau antibody. Long, fragmented axons with numerous branches were observed on the ephrin-A5 cells with anti-tau antibody (d). Note that anti-NSE and anti-tau revealed similar neurons with long axons on the control cells. However, on ephrin-A5 cells, anti-NSE detected neurons with only much shorter neurites, in contrast to anti-tau antibody. (e) A higher magnification of a degenerated axon on the ligand-expressing cells. Numerous gaps were observed along the axons. [Bars = 37.5 μm (a–d) and 18.75 μm (e).]