NERVE-TARGET CELL INTERACTIONS IN TASTE BUD MAINTENANCE

长期以来，味觉受体终末器官被认为依赖于它们的功能。 维持其结构完整性的神经支配。 真的，味道 去神经支配后的芽退化可能是最常见的 引用了感觉神经系统的神经营养作用的例子。 最近 然而，解剖学研究提出了关于 味蕾在中断后发生的结构变化， 味觉神经 值得注意的是，仓鼠的菌状味蕾 在脊索/舌去神经支配后，尽管去神经支配的芽表现出 可测量的形态变化，包括萎缩和破坏 味觉孔。 很明显，建筑物的结构完整性 味蕾对神经支配的依赖在物种之间有很大的不同 和乳头。 造成这种差异的因素将是 在这个项目中进行了调查。 味蕾退化的程度 失神经支配后的细胞更新率可能与 萌芽状态 这将用氚化胸苷进行评价 放射自显影 中高压电子显微镜将 建立失神经支配的神经细胞的超微结构类型， 味蕾 去神经可能不完全或 在仓鼠中， 用常规电子显微镜和标记研究进行评价。 的 拟议的标签研究将采用注射霍乱毒素或 确定神经纤维的神经节源的荧光示踪剂 在味蕾被激活之前，或者在味蕾被激活很久之后， 腱索/舌去神经支配。 这些研究将提供基本信息 关于神经和味蕾的相互作用。 这些研究与一个 了解神经如何维持味蕾，他们有 对解释持久性的相对脆弱性的影响 味觉与其他感官系统相比。

Taste receptor end-organs have long been recognized to depend upon their innervation for maintenance of their structural integrity. Indeed, taste bud degeneration following denervation is, perhaps, the most commonly cited example of neurotrophism for the sensory nervous system. Recent anatomical studies, however, have raised questions about the nature of the structural changes that occur in taste buds after interruption of the gustatory nerves. Notably, in the hamster, fungiform taste buds persist after chorda/lingual denervation although the denervated buds exhibit measurable morphological changes including atrophy and disruption of the taste pore. Apparently, the degree to which the structural integrity of taste buds depends on innervation differs dramatically between species and papillae. Factors accounting for this difference will be investigated in this project. The magnitude of taste bud degeneration following denervation might be related to the rate of cell turnover in the bud. This will be evaluated with tritiated thymidine autoradiography. Intermediate high voltage electron microscopy will establish the ultrastructural types of cells generated in denervated taste buds. The possibility that denervation may be incomplete or impermanent following gustatory nerve resection in hamsters will be evaluated with routine electron microscopy and labelling studies. The proposed labelling studies will employ injections of cholera toxin or fluorescent tracers to determine the ganglionic sources of nerve fibers that innervate taste buds before, or may innervate buds long after, chorda/lingual denervation. These studies will provide basic information concerning nerve-taste bud interactions. The studies are relevant to an understanding of how nerves maintain taste buds, and they have implications for explaining the relative vulnerability of permanence of taste compared with other sensory systems.