摘要：本文采用顺行溃变法对猫丘脑腹后内侧核内发自三叉神经尾侧脊束核的三叉丘系纤维终末的超微结构及其突触联系进行了研究。在电灼损毁三叉神经尾侧脊束核四天后，在电镜下发现丘脑腹后内侧核内的三叉丘系终未存在三种渍变形式，即：电子致密型溃变，电子透明型溃变及神经微丝型溃变，以电子致密型溃变终末最为常见。溃变的三叉丘系终末常较大，含有大量密集的圆形无颗粒小泡，在丘脑腹后内侧核内主要形成不对称型轴一树突触，多数溃变轴终末还参与形成以树突为中心的汇聚型突触复合体。

An Experimental Morphological Study on the Ultrastructure and Synaptic Connections of the Trigeminothalamic Terminals in the Ventroposteromedial Thalamic Nucleus of Cat

sui Hongjin,Gong Jin,Zhang Shuqin(Departemnt of Anatomy, Institute for Plastination, Dalina Medical College, Dalian 116027)

Abstract：Four days after electrolytic lesion in the caudal part of nucleus of spinal tract of 5th. nerve(Sp-5c),the ultrastructures and synaptic connecitons of the degenerated trigeminothalamic terminals were investigated by eletron microscope in 16 cats. The result showed that three types of degenerative terminals were found in the ventroposteromedial thalamic nucleus(VPM). The electron degenerated terminals were numerous. Most degenerated terminals of this type contained swollen and deformed mitochondria and enlarged synaptic vesicles in a dark matrix. Occasionally, a few electron lucent and neurofilamentous degenerated one could be seen. Trigeminothalamic terminals were large terminals containing numerous round agranular vesicles and making asymmetrical axo-dendritic synapses with dendrites. Sometimes a few degenerated axonal terminals made axo-axo-dendritic serial synapses with normal axonal terminals and dendrites. The degenerated terminals often take part in synaptic complex in which the center is a dendrite.

Keywords：ventroposteromedial thalamic nucleus; caudal part of nucleus of spinal tract of 5th. nerve; electrolytic lesin; synapse; cat

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