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Physological and anatomical study of the developmental process of rat trigeminal sensory branch.

大鼠三叉神经感觉支发育过程的生理解剖学研究。

基本信息

批准号：
03454124
负责人：
KUDO Norio
金额：
$ 3.9万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1993
项目状态：
已结题

项目摘要

Primary sensory afferents that connect the peripheral to the central nervous system navigate through a variety of substrates and across considerable distances before making contact with target cells, yet these fibers succeed in conveying the spatial organization of the sensory periphery to central relay nuclei with remarkable precision. Understanding how this mechanism is programd in development has been a major issue in neurobiology for many years.In this study, we showed that one of carbohydrate antigens which has 9-O-acetylated GD3-like structure might be involved in the fasciculation of nerve fibers which innervate whiskers in the same portion. The above molecule might be working as a recognition molecule for sensory nerves to distinguish itself from motor nerves when sensory and moter nerves travell together in the periphery.In the tigeminal nuclei where tigeminal primary afferents terminate, the barrel structure is formed after birth. In this perinatal period (E19-PO) of rat, the terminal arborization of fibers from different branches of the tigeminal nerve (maxillary vs.mandibular) occupy areas with overlap. The proportion of overlap between these two nerve terminals, however, decreases around perinatal period, suggesting fine pruning begin to take place before birth. After birth, as barrel structure is formed, the territories occupied by two branches of the trigeminal nerve are more clearly separated.In vitro study using co-culture system showed that there must be adhesion molecules which are specific to the tigeminal neurite elongation. We have not identified such molecules yet, however, cells in the embryonic skin tissue express molecules with more affinity for tigeminal neurites than that are expressed in retinal cells.

初级感觉传入，连接外周到中枢神经系统导航通过各种基板和相当长的距离，然后才与靶细胞接触，但这些纤维成功地传达空间组织的感觉外周到中央中继核具有显着的精度。在本研究中，我们发现一种具有9-O-乙酰化GD 3样结构的糖抗原可能参与了支配同一部位胡须的神经纤维的成束。当感觉神经和运动神经在外周共同走行时，上述分子可能作为感觉神经的识别分子，以区别于运动神经。在头束初级传入终止的头束核，桶状结构在出生后形成。在围生期（E19-PO），来自不同分支的肌神经（上颌与下颌）的纤维终末分支占据重叠区域。然而，这两个神经末梢之间重叠的比例在围产期前后减少，表明精细修剪开始在出生前发生。出生后，随着桶状结构的形成，三叉神经两支所占的区域被更清楚地分开，体外共培养系统的研究表明，必须有特异性的粘附分子对三叉神经突起的延伸。我们还没有鉴定出这样的分子，然而，胚胎皮肤组织中的细胞表达的分子比视网膜细胞中表达的分子对三叉神经突起具有更大的亲和力。