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Gliogenesis of astrocytes and oligodendrocytes in the neocortical grey and white matter of the adult rat: Electron microscopic analysis of light radioautographs
Author(s) -
Kaplan Michael S.,
Hinds James W.
Publication year - 1980
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.901930309
Subject(s) - white matter , electron microscope , biology , grey matter , gliogenesis , oligodendrocyte , cortex (anatomy) , population , neuroglia , cerebral cortex , astrocyte , microglia , anatomy , pathology , neuroscience , myelin , microbiology and biotechnology , central nervous system , immunology , magnetic resonance imaging , progenitor cell , physics , stem cell , inflammation , optics , radiology , demography , sociology , medicine
The identification of newly formed glial cells in the normal adult cerebral cortex is unresolved, since the identification of cells incorporating [H 3 ] thymidine has not been demonstrated in the adult by electron microscopy. In the present study, this problem has been studied by combining the resolution of the electron microscope with radioautography of 1‐μm sections. Four normal male rats were injected at 90 days of age with [H 3 ] thymidine and allowed to survive for 30 days. Labeled cells were found in 1‐μm sections of the visual cortex of these adult rats, and electron micrographs of selected cells from these same sections demonstrated clearly two types of cells labeled, astrocytes and oligodendrocytes, in both grey and white matter. The few cells that were tentatively identified as labeled microglia in the light microscope proved to resemble oligodendrocytes when examined in the electron microscope. In 1‐μm sections of the cortical grey matter, heavily labeled astrocytes (13 or more silver grains over the nucleus) represent about 0.08% of the total astrocytic population, and heavily labeled oligodendrocytes also were about 0.08% of their population. In the cortical white matter, about 0.03% heavily labeled astrocytes were observed, compared to about 0.07% heavily labeled oligodendrocytes. For all neuroglial cells in both white and grey matter, the average percent heavily labeled cells was 0.066%, a value large enough to suggest a slow turnover of neuroglial cells during the lifespan of the rats.