The distribution of zinc in the forebrain and midbrain of the lizard Gekko gecko. A histochemical study.

The distribution of zinc in the forebrain and midbrain of the lizard Gekko gecko was studied with the recently modified Timm method. Areas with a high intensity of staining are almost exclusively found in the telencephalon, although also some structures in the diencephalon display notable staining. Cortical areas that stain heavily are the deep zone of the subcortical layer of the small-celled medial cortex, the longitudinal association bundle that encompasses the large-celled medial cortex, and the dorsal cortex. Of the subcortical areas, particularly the anterior septal nucleus shows a high intensity of staining. Moderate to dense Timm staining is further observed in the ventral part of the anterior lateral cortex, the lateral septal nucleus, the striatum, the amygdaloid complex, and the dorsal ventricular ridge. Staining in the diencephalon is primarily confined to the stria terminalis and the ventromedial hypothalamic nucleus, whereas in the midbrain weak staining is observed in the ventral tegmental area and the periventricular layers of the tectum and the tegmentum. The presence of zinc in the gekkonid brain is discussed in relation to connections and neurotransmitters as studied in same species. Moreover, similarities in pattern of staining for zinc in mammals and reptiles and possible evolutionary implications are mentioned.