ABSTRACT
This chapter deals with the theoretical and technical problems posed by that complexity. Factors active on central nervous system (CNS) neurons, on the other hand, have been much more elusive, perhaps due to the extreme complexity of the CNS. Ideally, the final product of cell separation techniques should be a cell subpopulation whose components are homogeneous, unambiguously identifiable, sterile, viable, and amenable to study in tissue culture. The identification of neuronal subgroups is much more difficult in vitro than in vivo. Cell staining with fluorescent lectins has also been used to recognize neuronal subsets in vivo and in vitro. Cell-substratum interactions in vitro are likely to reflect cell interactions with neighboring cells and with extracellular matrix molecules in vivo. Stimulation of neuronal metabolism by trophic factors might facilitate the performance of specialized cell functions such as neurite outgrowth or neurotransmitter synthesis.
