Development of macroglial cells in the embryonic chick optic nerve

Macroglia development in the embryonic chick optic nerve was immunohistoche mically examined. The astrocytes with glial fibrillary acidic protein immun oreactivity were initially restricted to the retinal end of the optic nerve at stage 40, but had widely dispersed within the optic nerve in an out-sid e-in manner by stage 44. Oligodendrocytes with myelin basic protein immunor eactivity appeared at stage 38, and were widely distributed at stage 40. El ectron microscopic observation confirmed the presence of intermediate filam ents in the glial fibers and developing myelin at stages 40-41. The present results suggest that oligodendrocyte precursors undergo terminal different iation slightly earlier than astrocyte precursors with respect to the expre ssion of marker proteins. (C) 1999 Elsevier Science B.V. All rights reserve d.