结扎家兔颈总动脉和椎动脉后额区皮质超微结构变化──突触和突起

ULTRASTRUCTURE OF CEREBRAL CORTEX AFTER LIGATION OF THE COMMON CAROTID ARTERIES AND VERTEBRAL ARTERY IN RABBITS

成年家兔１５只，分实验组和对照组。实验组动物结扎双侧颈总动脉和一侧椎动脉后分成Ⅰ，Ⅱ，Ⅲ组，分别存活３０ｍｉｎ，１ｈ和２４ｈ．对两侧大脑半球额区皮质的相同部位进行了电镜观察。突触活性区（突触前、后膜和突触间隙）电子密度增加，分辨不清突触间隙，在Ⅱ组这种突触略多，发现极个别突触前、后膜断裂的突触；突触小泡数显著减少（ｐ＜０．００１），但三组间无显著变化（ｐ＞０．０５）；突触小泡分布多样，或聚集（Ⅰ组较多），或散在分布，或近突触前膜的小泡减少等形式；突触前、后成分内还见有空泡，在Ⅰ，Ⅱ组还有多泡体。轴突、树突和神经胶质突间的间隙不规则。轴突和树突内线粒体基质电子密度深，Ⅰ和Ⅱ组偶而可见轻度水肿的线粒体，Ⅲ组几乎不见；轴突和树突出现大小空泡。有髓鞘轴突发生轻度脱鞘变化，板层结构松散。神经胶质水肿，出现空泡和糖原颗粒积累，但线粒体正常。

Ten adult rabbits were divided into three groups,and ligation the bilateral common carotid arterise and unilateral verebral artery for,30 min,1 h and 24 h respectivly. Five animals were used as control. The ultrastructure of bilaterral frontal cortices were observed. The density of the whole synaptic active region (including pre-and post-synaptic cleft) increased.It was difficult to distinguish the synaptic cleft. In the second group the number of this kind of synapses was greater,and the synapse with damaged synaptic membranes was observed. In 30 min after the ligation, the number of synaptic vesicles reduced, but there was no obvious change in the second and third group. The distribution of synaptic vesicles was varied. Either clumped(in the first group) or scattered (in the first,second and third group).In the first and second group,multivesicle bodies were observed. The space among axons, dendrites and glial processes was irrcgular. Mitochomdrial matrix in axons and dendrites was dense, occasionally, a few swollon mitochondria could be observed in the first and second group. There were some vacuoles of different sizes. The myelin sheaths of affected axons displayed changes in lamellar structure, in place they were lirregularly dilated, and vacuoles appeared in the myelinated axons. Swollen glial processes contained glycogen granules, but the mitochondria remained normal.