NERVE TARGET CELL INTERACTION IN TASTE BUD MAINTENANCE

味蕾维持中的神经靶细胞相互作用

• 批准号: 6131797
• 负责人: MARK Celestin WHITEHEAD
• 金额: $ 20.15万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-04-01 至 2003-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6131797
• 关键词: axon; calcitonin gene related peptide; cell cell interaction; denervation; electron microscopy; ganglion cell; hamsters; immunocytochemistry; keratin; nerve injury; nervous system regeneration; neural cell adhesion molecules; neural growth associated protein; neuronal transport; postganglionic fiber; synaptogenesis; taste buds; tenascin

The peripheral gustatory system exhibits remarkable receptoneural plasticity. Taste bud receptor cells are continuously renewed and interact dynamically with nerves. Moreover, taste nerves respond to injury by regenerating to the tongue epithelium with great effectiveness. While structural features of receptoneural plasticity in taste are known, its neurochemical substrates are poorly understood. Recently, a few molecular factors have been associated with gustatory neurotrophism. The hamster is a critical model in this approach because fungiform buds atrophy, but the buds do not disappear after denervation, allowing the residual bud cells to be assessed for their differences relative to innervated cells as well as during reinnervation. In contrast, hamster foliate buds do disappear after denervation, allowing comparison with persistent fungiform buds. Hamster fungiform buds express NCAM, NSE and CGRP in centrally located gemmal cells. In denervated buds, these cells are dramatically reduced. The identifying features of immunopositive cells in innervated and denervated buds are not known, and the process by which bud cell become reinnervated, not understood. Electron microscopy (EM) combined with immunocytochemistry (IC) in normal buds will identify NCAM-, NSE- and CGRP-immunopositive cells with respect to their type, e.g., dark or light cells, and whether immunoreactive cells synapse with nerve fibers. In chronically-denervated buds, and buds with regenerating nerves, EM similarly will identify immunopositive gemmal cell types and any receptoneural contacts. A new tetramethylrhodamine dextran amine (TRDA) iontophoretic method for labeling single taste buds and their innervation will evaluate the timing and quantity of reinnervation relative to bud IC. Recent unexpected observations of sparse CGRP-immunopositive nerve fibers near some sensory-denervated buds raise.questions about the source of these fibers and their possible trophic influence upon residual bud cells. The cell bodies of oigin of these fibers will be determined by TRDA labeling in chronic sensory denervated animals. To better characterize the molecular nature of fungiform taste buds during degeneration and reinnervation, markers that have proven useful in other sensory systems for evaluating cell-cell recognition, differentiating receptor cells and growing axons, will be used in addition to anti-NCAM, -NSE and -CGRP. Use of these markers will be extended to include study of hamster foliate buds after glossopharyngeal nerve section. This will permit intraspecies comparison of anterior and posterior lingual taste bud fields which have responses to denervation that are dramatically different. The possibility that this difference relates to the different embryological origin of the two taste bud fields, i.e. as ectoderm vs. endoderm derivatives, will enhance the data interpretation.

外周味觉系统表现出明显的感受神经功能， 可塑性味蕾感受器细胞不断更新并相互作用 动态的神经。此外，味觉神经对损伤的反应是 有效再生舌上皮。而 味觉感受神经可塑性的结构特征是已知的， 神经化学底物知之甚少。最近，一些分子 这些因素与味觉神经营养作用有关。仓鼠是一只 这种方法的关键模型，因为菌状芽萎缩，但芽 在去神经支配后不消失，允许评估残留的芽细胞 因为它们相对于受神经支配的细胞的差异，以及在 神经再生相比之下，仓鼠叶状芽在 去神经支配，允许与持久的菌状芽比较。仓鼠 菌状芽在位于中央的芽细胞中表达NCAM、NSE和CGRP。在 失去神经支配的芽，这些细胞急剧减少。识别特征 免疫阳性细胞在神经支配和去神经芽是未知的， 芽细胞重新受神经支配的过程还不清楚。电子 用电镜结合免疫细胞化学的方法， 鉴定NCAM、NSE和CGRP免疫阳性细胞的类型， 例如，在一个实施例中，暗细胞或亮细胞，以及免疫反应细胞是否与神经突触 纤维在慢性失神经芽和再生神经芽中，EM 类似地，将鉴定免疫阳性生殖细胞类型和任何受体神经细胞类型。 联系人.一种新的四甲基罗丹明葡聚糖胺离子导入法 用于标记单个味蕾及其神经支配将评估 和相对于芽IC的神经再支配量。最近意外 观察一些附近稀疏的CGRP免疫阳性神经纤维， 失去感觉神经的芽提出了关于这些纤维来源的问题， 它们对残余芽细胞可能的营养影响。的细胞体 这些纤维的来源将通过TRDA标记在慢性感觉神经元中测定。 失去神经的动物为了更好地表征真菌状的分子性质， 味蕾在退化和神经再生过程中， 可用于其它感觉系统以评估细胞-细胞识别， 分化受体细胞和生长轴突，将被用于除了 抗NCAM、-NSE和-CGRP。这些标记的使用将扩大到包括 舌咽神经切断后地鼠叶状芽的研究这将 允许前舌味蕾和后舌味蕾的种内比较 对去神经有着截然不同反应的区域。的 这种差异可能与不同的胚胎起源有关。 在两个味蕾领域中，即作为外胚层与内胚层衍生物， 加强数据解释。