Fig. 7.

Bar graph showing the survival of embryonic day (E)15 trigeminal ganglion (TG) neurons cultured in serum-free culture medium (SFM) supplemented with 10% fetal calf serum, nerve growth factor (NGF) alone (50 ng/ml in SFM), neurotrophin-3 (NT-3) alone (50 ng/ml in SFM), and in NGF+NT-3 (50 ng/ml each in SFM). Percent survival of neurons in each case was determined as described in Materials and Methods. Note that TG neurons survive the best in the presence of both neurotrophins or NGF alone, moderately in the presence of NT-3 alone, and completely die off in SFM supplemented with fetal calf serum after 24 hours in culture. Differences in percentages of surviving neurons under different conditions were highly significant (P < 0.001).