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 subpalli al nuclei during the development of the central nervous system of the lizard Gallotia galloti. At the ultrastructural level these cells rese mble developing glial cells previously described in mammals. Early gli oblasts, light and dark glioblasts, astroblasts, oligodendroblasts, an d active oligodendrocytes predominate during the prenatal period. Imma ture and satellite astrocytes as well as light and medium oligodendroc ytes are the main cells observed between hatching and the early postna tal period. The early postnatal period is characterized by the presenc e of medium and satellite oligodendrocytes, most of which become dark oligodendrocytes in the adult. The thickness of myelin sheaths increas es between hatching and adult age. Gliofilament-rich mature astrocytes similar to those seen in the midbrain of these animals were never fou nd, not even in adults. The paucity of gliofilaments in immature astro cytes explains why we could not detect perikarya containing glial fibr illary acidic protein in the telencephalon of Gallotia galloti (Yanes et al., [1990] J. Comp. Neurol. 295:559-568). The presence of glioblas ts and immature astrocytes in the subpallial nuclei of lizards suggest s that these animals could serve as particularly valuable models in st udies of glial regeneration in the central nervous system. (C) 1997 Wi ley-Liss, Inc.