TRANSFORMING GROWTH-FACTOR-BETA-3, GLIAL-CELL LINE-DERIVED NEUROTROPHIC FACTOR, AND FIBROBLAST GROWTH FACTOR-II, ACT IN DIFFERENT MANNERS TO PROMOTE MOTONEURON SURVIVAL IN-VITRO

Developing chick motoneurons depend on as yet unidentified factors fro m the periphery and the central nervous system for their survival, Usi ng cultures of purified embryonic motoneurons, we show that basic fibr oblast growth factor (FGF-2) or transforming growth factor-beta 3 (TGF beta 3) each have only low survival-promoting activity when tested al one, but act synergistically to keep motoneurons alive for at least 3 days, Glial cell line-derived neurotrophic factor (GDNF), another memb er of the TGF beta family, was itself sufficient to maintain a populat ion of motoneurons, However, its effect was not significantly increase d by the addition of FGF-2, These results suggest that FGF-2, TGF beta 3, and GDNF, which are all present in the environment of developing m otoneurons, may act by different mechanisms as physiological survival factors for this population of central neurons. (C) 1996 Wiley-Liss, I nc.