Wenzel H J, Cole T B, Born D E, Schwartzkroin P A, Palmiter R D
Department of Neurological Surgery, Howard Hughes Medical Institute, Box 357370, University of Washington, Seattle, WA 98195, USA.
Proc Natl Acad Sci U S A. 1997 Nov 11;94(23):12676-81. doi: 10.1073/pnas.94.23.12676.
Zinc transporter-3 (ZnT-3), a member of a growing family of mammalian zinc transporters, is expressed in regions of the brain that are rich in histochemically reactive zinc (as revealed by the Timm's stain), including entorhinal cortex, amygdala, and hippocampus. ZnT-3 protein is most abundant in the zinc-enriched mossy fibers that project from the dentate granule cells to hilar and CA3 pyramidal neurons. We show here by electron microscopy that ZnT-3 decorates the membranes of all clear, small, round synaptic vesicles (SVs) in the mossy fiber boutons of both mouse and monkey. Furthermore, up to 60-80% of these SVs contain Timm's-stainable zinc. The coincidence of ZnT-3 on the membranes of SVs that accumulate zinc, and its homology with known zinc transporters, suggest that ZnT-3 is responsible for the transport of zinc into SVs, and hence for the ability of these neurons to release zinc upon excitation.
锌转运体-3（ZnT-3）是哺乳动物锌转运体家族中不断增加的一员，在大脑中富含组织化学反应性锌的区域（通过廷氏染色显示）表达，包括内嗅皮质、杏仁核和海马体。ZnT-3蛋白在从齿状颗粒细胞投射到海马门和CA3锥体神经元的富含锌的苔藓纤维中最为丰富。我们在此通过电子显微镜显示，ZnT-3修饰了小鼠和猴子苔藓纤维终扣中所有清亮、小而圆的突触小泡（SVs）的膜。此外，这些SVs中高达60%-80%含有可被廷氏染色的锌。ZnT-3在积累锌的SVs膜上的存在，以及它与已知锌转运体的同源性，表明ZnT-3负责将锌转运到SVs中，从而使这些神经元在受到刺激时能够释放锌。
