Fig. 7.

The soluble proteins of chromaffin granules (VP) promote the survival of chick ciliary ganglionic neurons at a level identical to that achieved with a saturating concentration of CNTF (10 ng/ml). Addition of neutralizing antibodies to either GDNF (20 μg/ml) or the TGF-βs TGF-β1, TGF-β2, and TGF-β3 (10 μg/ml) significantly reduces the promoting effect of VP. Addition of both antibodies completely abolishes the neurotrophic effect of VP (0.5 mg/ml), suggesting that GDNF and TGF-β are the long-sought ciliary neurotrophic proteins contained in VP. Data are given as mean ± SEM (n = 6), pvalues derived from Student’s t test are ***p < 0.001 for decreased survival after antibody treatment.