Jo S M, Won M H, Cole T B, Jensen M S, Palmiter R D, Danscher G
Department of Neurobiology, Institute of Anatomy, University of Aarhus, DK-8000, Aarhus, Denmark.
Brain Res. 2000 May 26;865(2):227-36. doi: 10.1016/s0006-8993(00)02227-7.
The present study was designed to localize zinc-enriched (ZEN) terminals in mouse olfactory bulb by means of ZnT3 immunocytochemistry (ICC) and zinc autometallography (AMG). The immunocytochemical staining of ZnT3 was closely correlated with the AMG pattern. ZEN terminals were defined as terminals showing both ZnT3 immunoreactivities and AMG granules. At the light microscopic level, dense staining patterns for ZnT3 immunoreactivity were seen in the granule cell layer and the olfactory glomerular layer. At the ultrastructural level, ZEN terminals were restricted to presynaptic terminals with single or multiple postsynaptic thickenings. The postsynaptic profiles contacting ZEN terminals appeared to be dendrites or somata of granule cells in the granule cell layer and periglomerular cells and mitral/tufted (M/T) cells in the olfactory glomerular layer. This suggests that two main sources of ZEN terminals are present in mouse olfactory bulb: (1) centrifugal fibres making asymmetrical synapses with granule cells and periglomerular cells, and (2) olfactory receptor terminals contacting dendritic profiles of M/T cells or periglomerular cells. The close correlation between ZEN terminals and the glutamatergic system is discussed.
本研究旨在通过锌转运体3免疫细胞化学（ICC）和锌自身金相法（AMG）对小鼠嗅球中富含锌的（ZEN）终末进行定位。锌转运体3的免疫细胞化学染色与AMG模式密切相关。ZEN终末被定义为同时显示锌转运体3免疫反应性和AMG颗粒的终末。在光学显微镜水平，在颗粒细胞层和嗅小球层可见锌转运体3免疫反应性的密集染色模式。在超微结构水平，ZEN终末局限于具有单个或多个突触后增厚的突触前终末。与ZEN终末接触的突触后轮廓似乎是颗粒细胞层中颗粒细胞的树突或胞体，以及嗅小球层中球周细胞和二尖瓣/簇状（M/T）细胞的树突或胞体。这表明小鼠嗅球中存在ZEN终末的两个主要来源：（1）与颗粒细胞和球周细胞形成不对称突触的离心纤维，以及（2）与M/T细胞或球周细胞的树突轮廓接触的嗅觉受体终末。本文还讨论了ZEN终末与谷氨酸能系统之间的密切关系。
