Gliogenesis in rat optic nerve: Astrocytes are generated in a single wave before oligodendrocytes☆

摘要: Abstract The time of origin for astrocytes in the rat optic nerve was investigated to determine whether this cell type is generated two waves, a first wave which occurs before formation oligodendrocytes and second after peak period oligodendrocyte formation. To answer question, multiple injections radioactive thymidine were administered rats production animals sacrificed several weeks injection. Thymidine-labeled cells identified with electron microscope. Of labeled cells, >80% are oligodendrocytes, 4% microglia, 2% astrocytes, remainder unclassifiable. thymidine-labeled not immunostained glial fibrillary acidic protein (GFAP), marker characteristic astrocytes. number glia postnatal week small fraction total neonatally. No evidence exists astrocyte as has been suggested study by Miller et al. (1985, Dev. Biol. 111, 35–41) ; rather, vast majority during 2 these data keeping classical studies gliogenesis. question arise directly from division an undifferentiated, common progenitor or committed lineage addressed combining autoradiography GFAP immunocytochemistry. Rats 1 hr injection their nerves processed immunocytochemistry autoradiography. During week, many GFAP. These observations demonstrate that divide neonatally give rise additional