THE CREEPER STAGE IN CEREBELLAR CLIMBING FIBER SYNAPTOGENESIS PRECEDES THE PERICELLULAR NEST - ULTRASTRUCTURAL EVIDENCE WITH PARVALBUMIN IMMUNOCYTOCHEMISTRY
THE CREEPER STAGE IN CEREBELLAR CLIMBING FIBER SYNAPTOGENESIS PRECEDES THE PERICELLULAR NEST - ULTRASTRUCTURAL EVIDENCE WITH PARVALBUMIN IMMUNOCYTOCHEMISTRY
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DOI：
10.1016/0165-3806(93)90209-s
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发表时间：
1993-12-17
期刊：
影响因子：
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通讯作者：
SOTELO, C
中科院分区：
文献类型：
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作者：
CHEDOTAL, A;SOTELO, C
在围产期大鼠，下橄榄复合体背帽的神经元短暂表达小清蛋白免疫反应性（PA-IR）。他们的终端无菌领域，特别是在flocollonodular叶，出现精细和卷曲的免疫染色纤维延伸的浦肯野板和新生分子层的精确带。较粗的PA-IR纤维，对应于前庭纤维，仅在浦肯野板下观察到。电子显微镜分析的PA-IR攀登纤维的带内，使我们能够研究它们的突触与浦肯野细胞。在出生时（PO），薄PA-IR攀爬纤维轴突在这些未成熟的神经元的胞体和树突的轮廓后爬行。它们在浦肯野细胞顶端树突的光滑表面上建立了一些突触接触，其中一些具有成熟的外观。在分子层的上部观察到PA-IR轴突生长锥。爬行纤维/浦肯野细胞突触发生的这个早熟阶段在这里被命名为“爬行者”阶段。在浦肯野细胞顶树突消退后（P5），PA-IR攀缘纤维位于浦肯野细胞体突起的周围，并与浦肯野细胞体突起形成突触，形成经典的细胞周围“巢”。在PO的成熟突触的存在表明早熟的攀爬纤维/浦肯野细胞突触发生，并建议其胎儿发病。因此，突触发生的过程分为两个步骤：（i）早期短暂的一步，与橄榄小脑地图形成的开始同时，可能参与维持投射的新生地形;（ii）后期步骤，涉及通过攀缘纤维对浦肯野细胞的多神经支配的消退，在给定的PA-IR带内对投射的细化，这一步骤为成人橄榄小脑系统带来了所需的突触特异性。
In perinatal rats, neurons in the dorsal cap of the inferior olivary complex transiently express parvalbumin-immunoreactivity (PA-IR). Their terminal axenic fields, particularly in the flocculonodular lobe, appear as precise bands of fine and convoluted immunostained fibers extending over the Purkinje plate and the nascent molecular layer. Thicker PA-IR fibers, corresponding to vestibular fibers, are observed only under the Purkinje plate. Electron microscopic analysis of the PA-IR climbing fibers within the bands allowed us to study their synaptogenesis with Purkinje cells. At birth (PO), thin PA-IR climbing fiber axons creep over these immature neurons following the contours of their perikarya and dendrites. They establish a few synaptic contacts, some of them of mature appearance, upon the smooth surface of Purkinje cell apical dendrites. PA-IR axonal growth cones are observed in the upper portion of the molecular layer. This precocious stage of climbing fiber/Purkinje cell synaptogenesis has been named here the 'creeper' stage. After the regression of the Purkinje cell apical dendrites (by P5), PA-IR climbing fibers are perisomatically located and synapse on Purkinje cell somatic protrusions, forming the classical pericellular 'nests'. The presence of mature synapses at PO indicates the precocity of climbing fiber/Purkinje cell synaptogenesis and suggests its fetal onset. Therefore, this process of synaptogenesis occurs in two steps: (i) an early transient one, simultaneous with the initiation of the formation of the olivocerebellar map, that could be involved in the maintenance of the nascent topography of the projection and (ii) a latter step which concerns the refinement of the projection within a given PA-IR band through the regression of multiple innervation of Purkinje cells by climbing fibers, step which brings the required synaptic specificity to the adult olivocerebellar system.