Distribution of neurofilaments in the telencephalon and mesencephalon of the adult and developing Gallotia galloti lizard.

The location and chronology during development of the immunoreactivity due to the presence of neurofilaments (NF) in telencephalon and mesencephalon of the lizard Gallotia galloti has been studied. For this purpose we have used two antibodies recognizing both phosphorylated and non phosphorylated neurofilaments (NF), a polyclonal Ab (NF 005), and a commercial monoclonal antibody (NF-200). The study was completed by using the Bielschowsky technique. During ontogeny, the anti-NF 005 immunoreactivity appeared at E40 in some tracts in mesencephalon and increased in intensity in isolated nerve fibers, tracts and commissurae till adult. However, a weak staining appeared in some neurons. In telencephalon, the reactivity was detected only in adult specimens. It was clearly more abundant in mesencephalon than in telencephalon, which could indicate that a greater complexity and functional importance exist in the lizard midbrain in relation to other primitive regions as the basal nuclei and cortical areas. In contrast to young specimens, the monoclonal anti-NF 200 was detected in neuronal perikarya, dendrites and axons in adults. Thus, in lizards, both antibodies highly recognized phosphorylated and non-phosphorylated forms of proteins of NF (NF-H). In mammals, these forms of proteins are implicated in axonal maturation. The presence of these NF in reptiles, identified for the first time, proved to be phylogenetically stable. The anti-NF immunoreactivity distribution occurs both caudo-rostrally and from the ventral to the dorsal regions.