NERVE-TARGET CELL INTERACTIONS IN TASTE BUD MAINTENANCE

味觉受体终末器官早已被认为依赖于它们的 维持其结构完整性的神经支配。 确实，味道 去神经支配后的芽退化也许是最常见的 引用了感觉神经系统的神经营养作用的例子。 最近 然而，解剖学研究对它的本质提出了疑问。 味蕾中断后发生的结构变化 味觉神经。 值得注意的是，在仓鼠中，菌状味蕾仍然存在 腱索/舌去神经后，尽管去神经芽表现出 可测量的形态变化，包括萎缩和破坏 味道毛孔。 显然，结构完整性的程度 味蕾取决于神经支配，不同物种之间差异很大 和乳头。 造成这种差异的因素是 本项目中进行了调查。 味蕾退化的程度 去神经支配后可能与细胞更新率有关 芽。 这将用氚化胸苷进行评估 放射自显影。 中高压电子显微镜将 建立去神经支配中产生的细胞的超微结构类型 味蕾。 去神经支配可能不完全或 仓鼠味觉神经切除术后的无常性将是 通过常规电子显微镜和标记研究进行评估。 的 拟议的标签研究将采用注射霍乱毒素或 荧光示踪剂确定神经纤维的神经节来源 之前会刺激味蕾，或者可能会在之后很长时间内刺激味蕾， 腱索/舌去神经支配。 这些研究将提供基本信息 关于神经味蕾相互作用。 这些研究与 了解神经如何维持味蕾，并且他们有 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.