cells screened from the substantia nigra largely lose their ability to express dopamine neurons (3,27). It is unclear how long the neural crest-derived stem cells can be preserved without loosing their stem cell potency and how much differential potency is preserved through numerous divisions. In this study, we characterized the NSCs derived from adult rat DRG, allowing in vitro propagation over 4–5 years. Three levels of characterization were investigated in these 4–5-year-old adult DRG NSCs in order to test the long-lasting potency of stem cells: (a) the proliferation and stem cell nature, (b) ability to express sensory features, and (c) the reliance on neurotrophins for differentiation.
