锌及锌转运蛋白ZnT3在小鼠海马苔藓纤维的一致性分布

COINCIDENT DISTRIBUTION OF ZINC IONS AND ZINC TRANSPORTER 3 IN MOUSE HIPPOCAMPAL MOSSY FIBERS

目的 研究游离锌离子和锌转运蛋白ZnT3在小鼠海马的定位以及二者的分布是否具有一致性。方法 应用锌TSQ荧光技术、锌金属自显影技术检测含锌神经元内的游离锌离子 ;应用免疫电镜技术检测ZnT3在含锌神经元轴突终末的分布。结果 游离锌离子和ZnT3免疫反应产物的分布在海马苔藓纤维内的分布具有一致性。在齿状回和CA3区的苔藓纤维内 ,锌和ZnT3蛋白定位于轴突终末的突触小泡。富含锌离子的含锌神经元轴突终末与CA3区锥体细胞的胞体和树突形成突触。尚可见锌离子存在于突触间隙内。结论 ZnT3向突触小泡内转运锌离子使锌离子聚积在含锌神经元轴突终末的突触小泡内 。

Objective To investigate the coincident distribution of free zinc ions and zinc transporter 3 (ZnT3) in the mouse hippocampus. Method Two zinc stainingtechniques, TSQ fluorescenceand zinc autometallography, were used for detecting zinc ions, and the immune electron microscopy was used for analyzingthe localization of ZnT3 proteins in zinc-containing neuronal terminals.Result The distribution of zinc ions and ZnT3 immunoreactivity were coincident in the hippocampal mossy fibers. In the mossy fibers of the dentate gyrus and the CA3 area, both zinc and ZnT3 were located in the synaptic vesicles. These zinc-enriched terminals made synapses with dendrites and/or cell bodies of the CA3 pyramidal neurons. Moreover, free zinc ions could be found in the synaptic cleft. Conclusion Zinc ions are transported into synaptic vesicles by ZnT3 and perform important neurophysiological function.