皮质丘脑投射神经元的超微结构及突触联系

THE ULTRASTRUCTURE AND SYNAPTIC RELATIONSHIP OF CORTICOTHALAMIC PROJECTION NEURONS IN THE AREA SI OF THE CAT

采用HRP逆行追踪技术与电镜相结合的方法,对猫大脑皮质体感Ⅰ区内皮质丘脑投射神经元的超微结构及突触联系进行了研究.结果证明,皮质丘脑投射神经元超微结构的特点为锥体形的胞体,胞浆丰富,含有多量的粗面内质网、游离核糖体及线粒体.HRP标记的皮质丘脑投射神经元作为突触后成份与轴突和树突分别形成轴-树突触、轴-体突触和树-体突触.这些结果提示:皮质丘脑投射神经元接受广泛的传入联系和皮质间的联系.

The synaptic relationship and ultrastructure of corticothalamic projection neurons in the cortex area SI of the cat were observed under the electron microscope.The results were as follows:The ultrastructural features of corticothalamic projection neurons were characterized by a relatively large nucleus,the nuclear membrane with distinct invagination,the nucleoplasm containing an oval hucleus and a large amount of euchromatin,the cytoplasm containing a large amount of ribosomes,the rough surfaced endoplasmic reticulum,the mitochrodria and Golgi apparatus.The labelled corticothalamic projection neurons formed synaptic connections with axon and dendrite terminals.In the somatosensory cortical area I three types of synapses were observed:(1) the axodendritic synapses formed by axonal terminals and HRP labelled dendrites:(2) the axosomatic synapses formed by axonal terminals and HRP labelled neurons;(3) the dendritic-somatic synapses formed by unlabelled dentrites and labelled neurons.These results showed that the corticothalamic projection neurons received the connections of afferent and intercotic fibers.