S100 immunoreactive glial cells in the forebrain and midbrain of the lizard Gallotia galloti during ontogeny.

We identified S100 immunoreactive cells in the brain of the lizard Gallotia galloti during ontogeny using immunohistochemical techniques for light and electron microscopy. In double labeling experiments with antibodies specific for S100A1 and S100B (anti-S100) and proliferative cell nuclear antigen (anti-PCNA), myelin basic protein (anti-MBP), phosphorylated neurofilaments (SMI-31), glial fibrillary acidic protein (anti-GFAP), or glutamine synthetase (anti-GS), we detected S100-like immunoreactivity in glial cells but never in neurons. Restricted areas of the ventricular zone were stained in the hypothalamus from E32 to postnatal stages, and in the telencephalon at E35, E36, and in adults.

Neuronal differentiation patterns in the optic tectum of the lizard Gallotia galloti.

This study examines in detail the sequences of morphological differentiation and deduces mode of migration into specific layers of all types of neurons present in the optic tectum of the lizard Gallotia galloti. It complements previous similar work on tectal histogenesis in the chick. It was found that the neuronal population diversity in the lizard tectum can be reduced by developmental analysis to three neuroblast classes, called Types I, II and III.

Regeneration of retinal axons in the lizard Gallotia galloti is not linked to generation of new retinal ganglion cells.

Using anterograde tracing with HRP and antibodies (ABs) against neurofilaments, we show that regrowth of retinal ganglion cell (RGC) axons in the lizard Gallotia galloti commences only 2 months after optic nerve transection (ONS) and continues over at least 9 months. This is unusually long when compared to RGC axon regeneration in fish or amphibians. Following ONS, lizard RGCs up-regulate the immediate early gene C-JUN for 9 months or longer, indicating their reactive state.