猫丘脑中央外侧核内脊丘系终末的超微结构和突触联系

ULTRASTRUCTURE AND SYNAPTIC CONNECTIONS OF SPINOTHALAMIC TERMINALS IN CENTRAL LATERAL NUCLEUS OF CAT THALAMUS

用顺行溃变的方法首次在电镜水平对猫丘脑中央外侧核内脊丘系终未的超微结构和突触联系进行了研究,在横断脊髓第四颈节一侧的外侧索和部分前索4～5天后,电镜下发现,在损毁同侧的丘脑中央外侧核的中段和尾段均有少量的溃变终未.脊丘系溃变的轴突终未有两种形式:电子致密型和电子透明型,以电子致密型多见,溃变的脊丘系终末大小形态各异,主要含大量密集的圆形突触小泡.根据小泡形状和终末大小的差异、溃变终末可分为以下两型:小圆型占82.5%;大圆型占17.5%.溃变轴突终未主要与树突形成不对称型轴——树突触,个别的突触后树突含突触小泡.溃变轴突终未多参与形成以树突为中心的汇聚型突触复合体、在由溃变轴突终未与树突所形成的轴一树突触中,有42.5%的数量位于突触复合体内.偶而见到溃变轴突终末参与形成的轴一轴一树突触.

In the present study, the whole lateral funiculus and a part of the ventral funiculus were sectioned at the fourth cervical segment of the spinal cord on one side. 1-5 days following the operation, the cats were perfused for electron microscopy. The results were as follows: Some of degenerated axonal (DA) terminals in the middle and caudal areas of the central lateral nucleus(CL ) were found on the same side. Two tpyes of DA terminals were identified. Type SR accounting for 82. 5%, and Type LR accounting for 17.5%. DA terminals and with dendrites primarily formed asymmetrical axo-dendrities synapses. Some of postsynaptic dendrites contained synaptic vesicles. DA terminals were also involved in the formation of the synaptic complex with a dentrite as a center. The axo-axo-dendritic synaps were occasionlly found.