大鼠丘脑束旁核的电镜观察

ELECTRON MICROSCOPIC STUDY ON THE PARAFASCICULAR NUCLEUS OF THALAMUS IN RATS

透射电镜下观察了大鼠ＰＦ中参与突触构成的各种轴突终末及突触联系为主的超微结构特征。ＰＦ中参与突触构成的轴突终末分为Ｒ、Ｆ、Ｐ及Ｇ终末四类，Ｒ终末包括ＳＲ及ＬＲ终末。ＳＲ终末占８１．５３％，为含有小圆形清亮小泡的轴突终末，所含小泡平均直径为４３ｎｍ。ＬＲ终末占９４．５％，含较大直径的圆形清亮小泡，平均直径为５６ｎｍ，与树突构成对称或不对称的轴—树突触。Ｆ终末占６．４４％，所含扁平小泡大小约６５ｎｍ×３２ｎｍ，还伴有圆形清亮小泡。Ｐ终末占２．２６％，所含小泡形态不定。Ｇ终末罕见，含有直径约１００ｎｍ～１２５ｎｍ的颗粒小泡，散在分布于终末内，同时还含有其他小泡。大鼠ＰＦ中的突触联系有轴—树、轴—轴、轴—体及树—树突触，分别占９６．６７％、０．５４％、２．４７％、０．３２％。大量的汇聚型。

The ultrastructure of the parafasicicular nucleus(PF), particularly its synaptic organization,were studied with electron microscopy in adult rats.There were four types of axonal terminals constituting synapses in the PF,On the basis of vesicle shapes,these were classified as round vesicle(R),flattened vesicle(F),polymorphic vesicle(P)and grain vesicle(G) terminals.R terminal could be subdivided intolarge round vesicle(LR) and small round vesicle(SR) terminals according to their different size of synaptic vesicles.SR terminals were most numerous in PF(81.53%),which contained round clear vesicles with a diameter of 43 nm.LR terminals (9.45%)were relatively large and contained round clear vesicles with a diameter of 56nm.F terminals(6.44%)contained flattened vesicles with the size of 65×32nm and few small round vesicles.P terminals (2.26%)contained vesicles of different shapes in a single terminal;G terminals (0.32%)were rarely observed in the PF; they contained randomly distributed grain vesicles with a diameter of 100—125nm.Synapses in the PF had four types,i.e.axo—dendritic,axo—somatic,axo—axonic and dendro—dendritic synapses.The percentages of these synapses were 96.67%,2.47%,0.54%and 0.32% respectively.In addition,many convergent,few radiant synaptic complexes and glomerulies were observed.