Scanning electron microscope observations of the outgrowth from embryonic chick dorsal root ganglia in culture.

Abstract

Cultures of chick dorsal root ganglia were examined with the scanning electron microscope. Fibroblasts, Schwann cells and neurites with their characteristic terminal filamentous growth cones were identified and their surface ultrastructure and inter-relationships described. Although exploratory filopodia of nerve growth cones were observed to pass both over and underneath the edges of wandering fibroblasts present at the periphery of the outgrowth, it was noted that the nerve bundles ultimately came to overlie sheets of fibroblasts. The neurites appeared generally bare along their lengths but were sometimes attached to the substrate or underlying fibroblastic sheet by small lateral projections. Some Schwann cells were observed to migrate freely between the neurites whilst others appeared to have wrapped around the nerve bundles in a manner suggestive of early myelination.