HETEROGENEOUS IMMUNOREACTIVITY OF GLIAL-CELLS IN THE MESENCEPHALON OFA LIZARD - A DOUBLE-LABELING IMMUNOHISTOCHEMICAL STUDY

Astrocytes and radial glia coexist in the adult mesencephalon of the l izard Gallotia galloti. Radial glia and star-shaped astrocytes express glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS). The same cell markers are also expressed by round or pear-shaped cell s that are therefore astrocytes with unusual morphology. Other round o r pear-shaped cells, also scattered in the tegmentum and the tectum, d isplay only GS. Electron microscopy reveals that these cells may be ol igodendrocytes. In this lizard, the GS is expressed in some oligodendr ocytes while this does not occur in the central nervous system of mamm als in situ. These results confirm that the cellular specificity of GS is different in various species and suggest that ependymal cells are also immunoreactive for GS but they do not contain GFAP. (C) 1998 Wile y-Liss, Inc.