Further differentiation of early neural tube explants in organ culture as studied by electron microscopy.

Chick embryo spinal cord has been explanted at 2-day stages, when few or no cells have formed axons, and cultured organotypically with adjacent tissues or isolated from all other tissues.Relatively mature nerve cells and glial cells, neurites and synapses could be seen in electron micrographs of cultures maintained for three to four weeks. Histological organization and some aspects of cell differentiation differed in the two types of cultures. Ependymal cells and randomly arranged cells, possibly modified glia, were seen only in cultures of neural tube with adjacent tissue; neurons and macroglia seemed to be more numerous in cultures of isolated neural tube.The development of characteristic cells, with variations according to culture conditions, provides the opportunity for further study of factors controlling patterns of proliferation and differentiation in the central nervous system from very early to advanced stages.