Cultures grown for 5 days in vitro were subjected to hypoglycemic stress (B, D) or to serum-free medium with normal glucose (A, C). During the last hour, BMP7 alone, BDNF alone, or BMP7 + BDNF were added, and nuclear (A, B) and cytoplasmic (C, D) P-Smad fluorescence were measured, as in Fig. 1. * indicates significant increase from control or indicated group with p<0.01, using one-way ANOVA followed by Newman-Keuls test; each group represents measurements of P-Smad fluorescence in at least 25 cells.