Cerebellar unipolar brush cells are targets of primary vestibular afferents:: an experimental study in the gerbil
Cerebellar unipolar brush cells are targets of primary vestibular afferents:: an experimental study in the gerbil
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DOI：
10.1007/s002210100790
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发表时间：
2001-09-01
影响因子：
2
通讯作者：
Mugnaini, E
中科院分区：
文献类型：
--
作者：
Diño, MR;Perachio, AA;Mugnaini, E
单极刷状细胞(UBC)是一种兴奋性谷氨酸能中间神经元，位于小脑颗粒层，其树突刷状突触以巨大的谷氨酸能突触形式从单个苔藓纤维终末接受兴奋性突触输入。UBC轴突在颗粒层内分支，形成与肾小球内颗粒细胞和UBC树突突触的大终末，在形态和功能上类似于外源性苔藓纤维形成的终末。到目前为止，仅有的胆碱乙酰转移酶(ChAT)阳性苔藓纤维是UBC的外源性传入，其中一些纤维起源于前庭内侧核和前庭降核。目的：确定UBC是否由初级前庭纤维支配。我们对沙土鼠的前庭小脑进行了示踪光镜和电子显微镜研究。用生物素标记的葡聚糖胺分别标记黄斑和管状前庭末梢器官。在适当的存活时间后，对沙土鼠进行中央前庭投射的光镜和电子显微镜分析。在结节和悬垂，标记的前庭纤维形成苔藓样终末，与所有注射的沙土鼠的颗粒细胞和脐带细胞都有突触。因此，携带静态和动态前庭信号的外源性苔藓纤维对UBC的神经支配代表了网络的第一次突触，它在颗粒层提供了一种强大的分布式兴奋形式。
The unipolar brush cell (UBC) is an excitatory glutamatergic interneuron, situated in the cerebellar granular layer, that itself receives excitatory synaptic input on its dendritic brush from a single mossy fiber terminal in the form of a giant glutamatergic synapse. The UBC axon branches within the granular layer, giving rise to large terminals that synapse with both granule cell and UBC dendrites within glomeruli and resemble in morphological and functional terms those formed by extrinsic mossy fibers. So far, the only demonstrated extrinsic afferents to the UBC are the choline acetyltransferase (ChAT)-positive mossy fibers, some of which originate from the medial and descending vestibular nuclei. To ascertain whether UBCs are innervated by primary vestibular fibers. we performed a tract-tracing light and electron microscopic study of the vestibulocerebellum in gerbils. Macular and canal vestibular end-organs were individually labeled by injection of biotinylated dextran amine. After an appropriate survival time, gerbils were then processed for light and electron microscopic analysis of central vestibular projections. In the nodulus and uvula, labeled primary vestibular fibers formed mossy terminals synapsing with both granule cells and UBCs in all of the injected gerbils. Thus, innervation of UBCs by extrinsic mossy fibers carrying static and dynamic vestibular signals represents the first synapse of networks that contribute a powerful form of distributed excitation in the granular layer.