A, Akt phosphorylation in neonate hippocampal slices challenged with DHPG and clustered EphB1/Fc applied alone or in combination. Note that neither DHPG nor clustered EphB1/Fc activated the PI-3-K pathway. The effect of DHPG, clustered EphB1/Fc, and DHPG + clustered EphB1/Fc in neonate hippocampal slices treated with the PI-3-K inhibitor, LY294002, is shown in B–D, respectively. Vales are means ± SEM. In B (n = 4), values from 40 to 80 min were significantly different from baseline values p < 0.05 (one-way ANOVA + Tukey's PLSD); in C (n = 5), values >70 min were significantly different from baseline values (p < 0.05); in D, the synergism between clustered EphB1/Fc and DHPG persists in the presence of LY294002. Values from 100 to 140 min were significantly different from values obtained with clustered EphB1/Fc alone (p < 0.05) (all points in the presence of LY294002).