猫丘脑中央外侧核内脊丘系终末的超微结构和突触联系

Fine Structure of the Spinothalamic Terminals in the Central Lateral Nucleus(CL) of the Cat Thalamus:An Anterograde Degeneration Study with Electron Microscope

本文应用顺行溃变的方法,首次在电镜水平对猫丘脑中央外侧内脊丘系终末的超微结构和突触联系进行了研究。在横断第四脊髓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,均有少量的溃变终末。脊丘系溃变的轴突终末有两种形式: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,溃变终末可分以下两型:SR型占82.5％;LR型占17.5％。溃变轴突终末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。溃变轴突终末多参与形成以树突为中心的汇聚型突触复合体。在由溃变轴突终末与树突所形成的轴——树突触中,有42.5％的数量位于突触复合体内。偶尔见到溃变轴突终末参与形成的轴-轴-树突触。

In the present study, the whole lateral and a part of the ventral funiculus were sec-tioned at the fourth cervical segment on one side, 4-5 days after this operation, the catswere perfused for electron microscopy. The results were showed as follow:A some of degen-erated axonal(DA) terminals in the middle and caudal areas of central lateral nucleus (CL)were found on same side. There were two types of DA terminals in the CL, the electrondense patlern was common;the electron lucent pattern could be found occasional. The DAterminals with various shapes contained numerous rounded vesicles. Two types of DA termi-nals could be identified, (1) type SR accounted for 82. 5%; (2)type LR accounted for 17.5%. DA terminals foumed asymmetrical axo-dendritics synapses with dendrites primarily.The postsynaptic dendrites occasionally contained synaptic vesicles. The DA terminals oftentook part in the synaptic complex in which the center is a dendrite. 42. 5% of the totalamount of axo-dendritic synapses in which the DA terminals took part were located insynaptic complexes,The axo-axo-dendritic synaps was occasionally found.