[Electron cytochemical identification of microglia].

The electron cytochemical reaction to nucleoside diphosphatase allows the differentiation in the rat brain of the cells of ectodermal orgin (neurocytes, astrogliocytes, oligodendrogliocytes) from the cells of mesodermal origin (microgliocytes, macrophages, endotheliocytes, pericytes). In the former group of cells, the product of the histochemical reaction was localized intracellularly (in the tubules of the cytoplasmic network and laminar complex) whereas in the latter it was localized only on the plasma membrane and never intracellularly.