Development and structure of the radial glia in the postnatal rat brain

Summary Postnatal development of radial glial cells was examined in albino rats. Until the 10th postnatal day radial glial cells were seen in the lateral ventricles, in the third ventricle (throughout its whole extent), in the aqueduct and in the fourth ventricle. The morphological appearance of radial glial cells was very variable in the different regions.After the 10th day radial glial cells (tanycytes) were seen only in the wall of the third ventricle. According to their appearance it was possible to undertake a morphological grouping. Considerable changes of the morphology of individual tanycytes could be observed in the median eminence and in the ventral hypothalamus between the 5th and 21st days.It was found that the peripheral processes of tanycytes ended near the nerve cells or on the cell body, on capillaries of the hypothalamic nuclei or on the pial surface. In a number of cases one tanycyte process contacted both the blood vessels of the hypothalamus and the pial surface.In view of their morphology the tanycytes can be assumed to transport material between different extracellular spaces, and/or to excrete material.The radial glial cells of the lateral ventricles can serve as guides for the postnatally formed microneurons and later can either transform to astroglia or degenerate.Part of this work was presented at the Annual Meeting of the Japanese Anatomical Society in Tokyo, 1979