Regional Distribution of Zinc Transporter 3 (ZnT-3)-Immunoreactivities in the Mouse Cerebellum

Jo, Seung Mook; Kim, Yong Kuk; Kim, Dae Jung; Jeong, Young Gil

Abstract

The presence of the zinc ion pump antibody ZnT-3 in zinc enriched (ZEN) cerebellar axonal terminals was detected in immunohistochemical sections of mouse cerebellum. All the ZnT-3-immunoreactive structures appeared punctate in the cerebellar cortex, while the white matter including intrinsic nuclei were void. The staining intensity varied in the different phylogenetic divisions of cerebellum. Archicortex was stained most intensively while paleo and in particular neocortex was stained only faintly. The ZnT-3 fraction was detected mainly in the upper half of the granule cell layer (GCL), although where they appeared ultrastructurally in small folded varicosities located corresponding to axon terminals of the Golgi cells. In the molecular layer (ML), the ZnT-3 staining was found to be distributed diffusely but in perpendicular radiating pattern through the layer but with the most intense staining in the upper half of the layer. Ultrastructurally the coarse patches of staining found in the granule cell layers were corresponded to presynaptic axon terminals contacting with granule cells. No ZnT-3 staining was observed in the Purkinje cell layer. The present results suggest that the Golgi cells in the mouse cerebellum are one of the ZEN neurons in the mammalian brain. In conclusion, we first showed putative ZEN terminals in the mouse cerebellum. These results will provide a valuable aid for investigation of further localization of the ZEN neurons in the mammalian cerebellum. More work is needed to further characterize the ZEN terminals, and so autometallographical studies are currently being investigated in this laboratory.