Radioautographical observations of development and appearance of glia cells in brain I. Apperarace of ectodermal glial cell aggregates in rodent brain

뇌신경교세포(腦神經膠細胞) 집단(集團)의 발생(發生)과 이동(移動)에 대한 방사선(放射線) 자기법적(自記法的) 관찰 I, 설치류 뇌(腦)에 외배엽성(外胚葉性) 신경교세포(神經膠細胞) 집단(集團)의 출현(出現)에 대하여

The present study was designed to investigate the appearance of the congenital aggregates of the ectodermal glial cells in the brain of the normal rodents. The brain samples were taken from mice fetus, juvenile mice, rats and rabbits. The appearance regions of the glial cell aggregates (GCA) were investigated and the cells in the GCA were identified with electron microscope. 1. GCA in the mouse fetus tended to be higher in cell density, larger in size and lower frequency in appearance than juvenile mouse. The regions of higher appearance frequency of GCA in the juveniles of mice, rats and rabbits were ordered as subependymal layer in the collateral trigone of lateral ventricles, molecular layer of the neocortex, inner layer except the molecular layer in the neocortex, cerebral medulla, corpus callosum and hippocampus. Appearance frequency of GCA in the neonatal mice tended to be higher until 5 day after birth, and were markedly decreased on 10 and 15 day after birth. 2. GCA tended to be closed on one side of the blood vessels or neurons but not perivascular or perineuronal appearance. 3. In electron microscophy, GCA were composed of immature oligodendrocytes and astrocytes in the subependymal, and tended to be more mature and loose in the neocortex and to be appended some microglia cells with age. The cells in the GCA of older mice tended to be more mature than in young mice.