DISTRIBUTION OF NEUROFILAMENTS IN THE TELENCEPHALON AND MESENCEPHALONOF 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 mesen cephalon of the lizard Gallotia galloti has been studied. For this pur pose we have used two antibodies recognizing both phosphorylated and n on phosphorylated neurofilaments (NF), a polyclonal Ab (NF 005), and a commercial monoclonal antibody (NF-200). The study was completed by u sing the Bielschowsky technique. During ontogeny, the anti-NF 005 immu noreactivity appeared at E40 in some tracts in mesencephalon and incre ased in intensity in isolated nerve fibers, tracts and commissurae til l adult. However, a weak staining appeared in some neurons. In telence phalon, the reactivity was detected only in adult specimens. It was cl early more abundant in mesencephnlon than in telencephalon, which coul d indicate that a greater complexity and functional importance exist i n the lizard midbrain in relation to other primitive regions as the ba sal nuclei and cortical areas. In contrast to young specimens, the mon oclonal anti-NF 200 was detected in neuronal perikarya, dendrites and axons in adults. Thus, in lizards, both antibodies highly recognized p hosphorylated and non-phosphorylated forms of proteins of NF (NF-H). I n 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 di stribution occurs both caudo-rostrally and from the ventral to the dor sal regions.