GLIAL CELLS IN THE LIZARD GALLOTIA GALLOTI SUBPALLIAL NUCLEI DURING ONTOGENY : AN ULTRASTRUCTURAL STUDY

A study was made of the maturation of glial precursors in the subpallial nuclei during the development of the central nervous system of the lizard Gallotia galloti. At the ultrastructural level these cells resemble developing glial cells previously described in mammals. Early glioblasts, light and dark glioblasts, astroblasts, oligodendroblasts, and active oligodendrocytes predominate during the prenatal period. Immature and satellite astrocytes as well as light and medium oligodendrocytes are the main cells observed between hatching and the early postnatal period. The early postnatal period is characterized by the presence of medium and satellite oligodendrocytes, most of which become dark oligodendrocytes in the adult. The thickness of myelin sheaths increases between hatching and adult age. Gliofilament-rich mature astrocytes similar to those seen in the midbrain of these animals were never found, not even in adults. The paucity of gliofilaments in immature astrocytes explains why we could not detect perikarya containing glial fibrillary acidic protein in the telencephalon of Gallotia galloti (Yanes et al., [1990] J. Comp. Neurol. 295:559–568). The presence of glioblasts and immature astrocytes in the subpallial nuclei of lizards suggests that these animals could serve as particularly valuable models in studies of glial regeneration in the central nervous system. J Morphol 233:1–13, 1997. © 1997 Wiley-Liss, Inc.