The dependence on or induction of DRG NSCs sensory differentiation by NGF or BDNF, which occurs normally during development of migrating neural crest cells differentiating into DRG neurons (2,29,35) was determined. Both eDRG- and aDRG NSCs were supplemented with exogenous NGF (10 ng/ml, BD Biosciences, Bedford, MA) or BDNF (10 ng/ml, Alomone Labs, Israel) immediately after subplating, continuing twice per week until the end of the experiment. Neurotrophin controls received an equal volume of medium. For quantitative analyses, aDRG NSCs were dissociated by incubating them at 37°C for 45 min in a digest medium containing 10 mg papain, 100 mg protease, 10 mg DNase1, 12.4 μl 1 M MgSO4 per 100 ml HBSS. The cells were centrifuged, washed three times, and plated at a concentration of 3,000–3,500 cells per well. The medium was the same as described above and treatment consisted of 10 ng/ml NGF or BDNF; controls received an equal volume of medium. After 28 days, cells were fixed with 4% formaldehyde for immunostaining for TrpV1 expression for subsequent counting (described below). Because BDNF influences neuronal maturation, we investigated
