Radial glia and astrocytes in developing and adult telencephalon of the lizard Gallotia galloti as revealed by immunohistochemistry with anti‐GFAP and anti‐vimentin antibodies

Abstract

The development of radial glia and astrocytes in the telencephalon of the lizard Gallotia galloti was studied by immunohistochemistry with anti-vimentin and anti-GFAP antibodies. Vimentin appears at embryonic stage 32 (E32) in the proliferative zone of the lateral ventricle and subpial end-feet in the marginal zone. At E34-35 the staining intensity for vimentin in all radial glia is maximal. It then decreases and disappears in most structures in adult animals. GFAP appears at E35 in the end-feet in the marginal zone and its intensity increases until adulthood, particularly in radial and sinuous fibers and in fibers that originate from the sulci and invade the ventral striatum and the septum. In contrast, the reaction is weak in the cortex, in the anterior dorso-ventricular ridge, and in the amygdala nuclei. Radial glia is still present in the adult, and the composition of its intermediate filaments changes during development from vimentin to GFAP. No GFA-positive cell bodies except those of ependymal glia were detected in telencephalon.

Neurogenesis and Neuronal Regeneration in the Adult Reptilian Brain

“…They include microglial cells with a distinctly laminar pattern of distribution and oligodendroglial cells in areas with myelinated fibers [García-Verdugo et al, 1981;Yanes et al, 1992;Font et al, 1995]. No GFAP-positive astrocytes have been observed in the intact telencephalon of lizards [Dahl et al, 1985;Yanes et al, 1990;Pérez-Cañellas and García-Verdugo, 1996; but see Monzó n-Mayor et al., 1990]. In fact, GFAP immunohistochemistry has confirmed that, unlike adult mammals and birds, in the adult lacertilian telencephalon radial glial cells are the predominant astroglial element ( fig.…”

“…In lizards, the cellular composition of the VZ has been studied in some detail and has been shown to comprise two main cell types [García-Verdugo et al, 2000]. The VZ cells directly in contact with the ventricular lumen are almost exclusively radial glial cells that stain positive for GFAP and extend radial fibers that ascend into the overlying neuropil [García-Verdugo et al, 1981;Yanes-Méndez et al, 1988a, b;Yanes et al, 1990]. A second cell type found immediately adjacent to the VZ consists of cells with the ultrastructural characteristics of young migrating neurons.…”

“…The morphology and distribution of radial glia in the adult reptilian brain has been investigated with traditional methods, such as Golgi staining and electron microscopy [Stensaas and Stensaas, 1968;García-Verdugo et al, 1981], as well as immunohistochemically with antibodies against glial fibrillary acidic protein (GFAP) or glutamine synthetase [Onteniente et al, 1983;Dahl et al, 1985;Kriegstein et al, 1986;Monzó n-Mayor et al, 1990;Yanes et al, 1990;Ká lmá n et al, 1994]. Radial glia cell bodies are elongated or cuboidal and join those of neighboring ependymal cells via junctional complexes.…”

“…The cells generated in the VZ migrate within the first few days of their life towards specific target areas in close association with the processes of radial glial cells. Ependymal or radial glial cells are adult derivatives of the embryonic radial glia, the somata of which form a monostratified or pseudostratified epithelium lining the cerebral ventricles [Ulinski, 1990;Yanes et al, 1990]. Radial glia are generated before neurogenesis and guide neuronal migration in the developing brain [Rakic, 1990].…”

Proliferation, Migration, and Survival of Cells in the Telencephalon of the Ball Python, Python Regius

“…Most are radial glial cells while the rest are young migrating neurons (García-Verdugo et al, 1981;Yanes et al, 1990;Yanes-Méndez et al, 1988;Yanes-Mendez et al, 1988). Radial glial cells in the VZ are likely the stem cells for adult neurogenesis in reptiles but evidence supporting this hypothesis in reptile studies is limited (Font et al, 1995b).…”