大鼠孤束核内脑啡肽样免疫反应阳性结构及其轴突终末的突触联系

本文应用免疫细胞化学方法在光镜与电镜下观察了大鼠孤束核内脑啡肽样免疫反应（ＥＮＫ－ＬＩ）阳性结构的分布特征和ＥＮＫ－ＬＩ轴突终末的突触联系以及非突触性关系。结果表明：（１）经秋水仙素处理的大鼠，其孤束核内有许多ＥＮＫ－ＬＩ胞体的分布；而未经秋水仙素处理的大鼠，其孤束核内可见密集的ＥＮＫ－ＬＩ纤维与终末；ＥＮＫ－ＬＩ胞体、纤维和终末主要分布于锥体交叉平面至闩平面的孤束核内侧亚核与胶状质亚核。（２）ＥＮＫ－ＬＩ阳性产物主要定位于小圆形清亮囊泡外表面、大颗粒囊泡内和线粒体外表面等处。（３）ＥＮＫ－ＬＩ轴突终末主要与阴性树突形成轴－树突触。（４）阴性轴突终末终止于ＥＮＫ－ＬＩ轴突终末上，形成轴－轴突触。（５）ＥＮＫ－ＬＩ轴突终末与阴性轴突终末形成非突触性的轴－轴并靠。以上结果提示孤束核内的ＥＮＫ－ＬＩ神经成分主要通过突触后机制、也不排除突触前作用，参与孤束核中内脏信息的整合过程，而且这一作用又受到非ＥＮＫ－ＬＩ神经成分的调控。

THE DISTRIBUTION OF ENKEPHALIN-LIKE IMMUNOREACTIVE STRUCTURES AND THE SYNAPTIC CONNECTION OF THE AXON TERMINALS IN THE NUCLEUS TRACTUS SOLITARIOUS OF THE RAT

By using immunocytochemistry the distribution of enkephalinlike immunoreactive(ENK-LI)structures and the synaptic connection of the axon terminals in the nucleus tractus solitarious(NTS)of rat were examined under both light and electron microscopes.The re suits showed at:(1)Numerous ENK-LI perikarya were observed in the NTS with pretreatment of colchicine,but dense ENK-LI fibers and terminals were only noted without the pretreatment of clochicine,ENK-LI perikarya,fibers and terminals were mainly distributed in the medial and gelatinus subnuclei of the NTS at levels from the pyramidal decussation to the obex.(2)ENK-LI reaction product was mainly localized in large dense core vesicles,on the surface of small clear vesicles as well as the out memberane of mitochondria:(3)ENKLI axon terminals mainly formed axo-dendritic synapses with no ENK-LI dendrites.(4)No ENK-LI axon terminals constituted axoaxonic synapses with ENK-LI axon terminals.(5)ENK-LI axon terminals made axo-axonic contacts with no ENK-LI axon terminals. These results suggest that within NTS ENK-LI neuronal elements are involved in the modulation of the visceral information by postsynaptic mechanism,perhaps also by pre-synaptic mechanism,and this process may also be regulated by no ENK-LI neuronal elements.