Figure 4.

Inhibition of the effects of the Eph ligands by the competitive inhibitor EphA3-Fc. Medial hippocampal neurons were cocultured with the ligand-expressing or control cells in the presence of the soluble extracellular domain of EphA3, EphA3-Fc. The cells were incubated for 48 hr before analysis. Fifteen to 20 neurons were quantitated for each parameter. (a) Inhibition of ephrin-induced growth promotion by EphA3-Fc. In the presence of EphA3-Fc, the total axonal length of medial hippocampal neurons cocultured with ligand-expressing cells was comparable to that elicited by control cells. (b) Inhibition of axonal fragmentation by EphA3-Fc. (c) Reduction of the total number of axonal branches by EphA3-Fc. (d) Inhibition of fragmentation of axonal branches by EphA3-Fc. Asterisks indicate significant differences (P < 0.05; t test) between cultures with and without the inhibitor.