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FUNCTIONAL CONNECTION BETWEEN TASTE RECEPTOR CELLS AND AFFERENT NERVES IN THE LOWER VERTEBRATE

低等脊椎动物味觉感受器细胞与传入神经之间的功能连接

基本信息

批准号：
63540587
负责人：
NAGAI Takatoshi
金额：
$ 1.22万
依托单位：
TEIKYO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

项目摘要

The morphological and neurophysiological basis to reveal the functional connection between the taste receptor cells and the afferent nerve were obtained in a novel animal model: the Mexican salamander, axolotl (Ambystoma mexicanum).The response property to four basic taste and other chemicals were surveyed with a whole nerve recording of the glossopharyngeal nerve (IX nerve). Salts were the most potent stimulant, but amino acids were the least even at 50 mM. The IX nerve contained mechanosensory fibers also, possibly with a larger diameter than chemosensory ones.The cell body of the IX nerve was labelled by cobaltic-lysine (Co-lys). The process, when successfully labelled, was pseudo-unipolar. The labelled cells (the average diameter = 23 mum) were uniformly distributed mainly in the rostral part of the combined IX-X nerve ganglion. However, the double labelling of Co- lys and HRP showed that the IX nerve was somewhat mixed up with the vagus nerve in their distributions. The structure of the IX nerve ganglion differed from that of mammals and frogs.The afferent and efferent components of the IX nerve in the brainstem were transganglionically labelled with Co-lys. Majority of the afferent fibers formed strong ascending and descending bundles in the solitary fasciculus. The rest of afferent fibers formed in the spinal tract of trigeminal nerve a weak bundle. The cell bodies of the efferent neurons had developed dendritic arbors, and formed a longitudinal cell column. In the brainstem, the topography of the IX nerve was basically similar to that in frogs.The peripheral branches of the IX nerve beneath a lingual epithelium were labelled with a fluorescent carbocyanine dye, DiI. To view the nerve terminals and the taste cells, the fluorescence and the differential interference optics are being combined. The recording from the labelled afferents will reveal their sensory function.

本研究以墨西哥钝口螈（Ambystoma mexicanum）为动物模型，采用舌咽神经（IX神经）全神经记录技术，研究了舌咽神经对四种基本味觉和其他化学物质的反应特性，为揭示味觉感受细胞与传入神经之间的功能联系提供了形态学和神经生理学基础。盐是最有效的兴奋剂，但氨基酸是最少的，甚至在50 mM。IX神经含有mechanosensory纤维也，可能具有更大的直径比chemosensory的。IX神经的细胞体标记的钴赖氨酸（Co-赖氨酸）。当成功标记时，该过程是假单极的。标记细胞（平均直径= 23 μ m）均匀分布，主要在吻部的联合IX-X神经节。而Co- lys和HRP双标记显示，IX神经与迷走神经在分布上有些混淆。第IX神经节的结构与哺乳动物和蛙的不同，脑干中第IX神经的传入和传出成分均被Co-Lys跨节标记。多数传入纤维在孤束内形成强的升、降束。其余传入纤维在三叉神经脊束内形成弱束。传出神经元胞体发育成树突状，形成纵行细胞柱。在脑干中，IX神经的地形基本上是相似的，在青蛙。IX神经的周围分支舌上皮下标记的荧光碳菁染料，DiI。为了观察神经末梢和味觉细胞，将荧光和微分干涉光学相结合。来自标记的传入神经的记录将揭示它们的感觉功能。