Xu Z C, Wilson C J, Emson P C
Department of Anatomy and Neurobiology, University of Tennessee, Memphis 38163.
Neuroscience. 1992;48(1):95-110. doi: 10.1016/0306-4522(92)90341-x.
Two to six months after implantation of fetal striatal primordia into the kainic acid-lesioned neostriatum of adult rats, spiny neurons in the grafts were stained intracellularly with biocytin. To determine whether the spiny neurons in the grafts differentiate morphologically as in the host neostriatum, the intracellularly stained spiny neurons in the grafts were studied with light and electron microscopy and compared with that of spiny neurons in the host neostriatum. The spiny neurons in the grafts had ovoid or polygonal cell bodies with dendrites radiating in all directions. The somata were smooth and the dendrites, except for their most proximal portions, were rich in spines. All these features resembled the appearance of spiny neurons in the intact neostriatum. However, quantitative studies showed that the somata of spiny neurons in the grafts were larger than those in the host neostriatum (projected cross-sectional areas of 230 +/- 64.6 microns 2 in the grafts and 158 +/- 28.9 microns 2 in the host) and the spine density of graft neurons was lower than that of host neurons. Cells near the border of the grafts had dendrites extending both into the graft and into the host neostriatum. In these cells, the dendrites in the grafts had fewer spines than the dendrites in the host tissue. The axons of spiny neurons in the grafts had very large and dense intrastriatal collateral arborizations, which occupied a much larger volume than that of the dendritic domain of the parent cells. The local axonal arborizations of each of these cells filled almost the entire graft. In some cells, axonal branches were traced outside the grafts and were seen to enter the internal capsule fascicles. Unlike spiny neurons in the normal adult neostriatum, the spiny cells of the graft could have nuclear indentations. With this exception, the ultrastructural features of spiny neurons in the grafts were very similar to those in the hosts. Many unlabeled boutons made synapses on identified spiny neurons in the grafts. Terminals with small round vesicles made synaptic contacts on dendritic shafts and dendritic spines, while terminals with flattened or pleomorphic vesicles contacted somata, dendrites, and dendritic spines. Labeled axon collaterals of graft neurons made symmetrical synapses on somata, dendrites and spines in the grafts and in the host neostriatum. In the grafts, more than 60% of the axon terminals contacted dendritic shafts. The proportion of axosomatic and axospinous synapses varied substantially from cell to cell.(ABSTRACT TRUNCATED AT 250 WORDS)
将胎儿纹状体原基植入成年大鼠经 kainic 酸损伤的新纹状体两到六个月后，用生物胞素对移植物中的棘状神经元进行细胞内染色。为了确定移植物中的棘状神经元是否如宿主新纹状体中的神经元那样在形态上发生分化，对移植物中经细胞内染色的棘状神经元进行了光镜和电镜研究，并与宿主新纹状体中的棘状神经元进行比较。移植物中的棘状神经元具有卵圆形或多边形的细胞体，其树突向各个方向辐射。细胞体表面光滑，除了最近端部分外，树突富含棘突。所有这些特征都类似于完整新纹状体中棘状神经元的外观。然而，定量研究表明，移植物中棘状神经元的细胞体比宿主新纹状体中的大（移植物中预计横截面积为 230±64.6 平方微米，宿主中为 158±28.9 平方微米），且移植物神经元的棘突密度低于宿主神经元。移植物边界附近的细胞有树突延伸到移植物和宿主新纹状体中。在这些细胞中，移植物中的树突比宿主组织中的树突棘突少。移植物中棘状神经元的轴突在纹状体内有非常大且密集的侧支分支，其占据的体积比母细胞树突区域的体积大得多。每个这些细胞的局部轴突分支几乎充满了整个移植物。在一些细胞中，轴突分支延伸到移植物外并进入内囊束。与正常成年新纹状体中的棘状神经元不同，移植物中的棘状细胞可能有核凹陷。除此之外，移植物中棘状神经元的超微结构特征与宿主中的非常相似。许多未标记的终扣与移植物中已鉴定的棘状神经元形成突触。带有小圆形囊泡的终末与树突干和树突棘形成突触接触，而带有扁平或多形囊泡的终末与细胞体、树突和树突棘接触。移植物神经元的标记轴突侧支在移植物和宿主新纹状体中的细胞体、树突和棘上形成对称突触。在移植物中，超过 60%的轴突终末与树突干接触。轴体突触和轴棘突触的比例因细胞而异。（摘要截断于 250 字）
