Figure 1.

0-DIV SCG neurons deprived of NGF in the presence of BAF cannot be rescued by NGF, in contrast to established neuronal cultures. (A) 0-DIV SCG neurons were cultured for 24 h in the presence or absence of 50 ng/ml NGF and/or 100 μM BAF (treatment). After 24 h, half the medium was replaced with medium containing 200 ng/ml NGF (addition indicated by arrow), and NGF was replenished every 3 d. Between 150–300 neurons were counted per well, initially after 4–5 h of plating and in the same areas every 2–3 d as indicated, up to 25 d. (B) Purified SCG neurons were cultured for 6 d in medium containing 50 ng/ml NGF, after which some cultures were deprived of NGF by removal of medium and addition of anti-NGF antibody (treatment). NGF-maintained or NGF-deprived neurons were cultured in the absence or presence of 100 μM BAF for 3 d, after which NGF was added to all the wells as described above (addition indicated by right-most arrow). Neurons in a defined area were counted once immediately after medium replacement, and surviving cells were counted over the next 25 d. Percent survival was calculated by normalizing the counts to the counts of neurons maintained continuously in the presence of NGF (55–95% survival between different experiments). Data represent mean ± SD derived from four independent experiments in which deviations between triplicate wells were <5%.