脊髓侧角区5-HT、TH、SP和L-ENK免疫反应纤维和终末的超微结构

本文应用免疫细胞化学ABC法,在电镜下观察脊髓侧角区单胺能和某些肽能纤维及末梢的突触组合。大鼠侧角内的5-HT、TH、SP和L-ENK免疫反应纤维均为无髓纤维。在侧角细胞簇内,这些纤维穿行于胞体之间,有的与胞体相邻,但很少与胞体形成轴-体突触。这些单胺和肽类纤维也与树突伴行,在树突束内数量最多。有时一小束无髓纤维都含同一种免疫反应物质。轴-树突触是各种免疫反应纤维终末所形成突触的主要形式。各种纤维终末所含的小泡多为圆清亮小泡,或兼有少数大颗粒泡。SP和L-ENK纤维膨体内的小泡与其终末内者不同,大颗粒泡较多,有时约占半数。各种免疫反应终末所组成参与的突触,对称或非对称型均不显现优势。

ULTRASTRUCTURE OF TH, 5-HT, SP AND L-ENK IMMUNOREACTIVE FIBERS AND BOUTONS IN THE LATERAL HORN OF THE RAT SPINAL CORD

The synaptic organization of monoaminergic and peptidergic fibers in the lateral horn of the rat spinal cord was studied under electron microscopy by immunocytochemistry ABC method. TH, 5-HT, SP and L-ENK immunoreactive fibers in the lateral horn were unmyelinated. In the cell clusters of the lateral horn these fibers appeared in the space between cell bodies and some pressed on the soma, but axosomatic synapses were seldom found. Many immunoreactive fibers ran along the dendrites, especially in the dendritic bundle. Occasionally a small bundle of unmyelinated fibers all contained the same kind of substance. Majority of the immunoreactive boutons formed axodendritic synapses. All the four kinds of neuroactive substancecontaining boutons or varicosities contained almost round clear vesicles or plus a few large granular vesicles. The SP and L-ENK varicosities included more large granular vesicles than the boutons did. Both symmetrical and asymmetical contacts were encountered in TH, 5-HT, SP and L-ENK boutons.