NERVE-TARGET CELL INTERACTIONS IN TASTE BUD MAINTENANCE

味觉感受器末端器官长期以来一直被认为依赖于它们的 维持其结构完整性的神经支配。的确，品味 去神经支配后的芽体退化可能是最常见的 引用了感官神经系统营养不良的例子。近期 然而，解剖学研究已经提出了关于 味蕾在味觉中断后发生的结构变化 味觉神经。值得注意的是，在仓鼠身上，真菌状的味蕾持续存在。 在去脊神经/舌神经后，尽管去神经的芽表现出 可测量的形态变化，包括萎缩和视网膜瘤的破坏 尝一尝毛孔。显然，结构完整性的程度 味蕾对神经支配的依赖在不同物种之间存在巨大差异 还有乳头状。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 去神经后可能与脑细胞的周转率有关。 萌芽。这将用氚胸苷进行评估。 放射自显影。中高压电子显微镜将 失神经损伤后细胞超微结构类型的建立 味蕾。去神经的可能性可能是不完全的 仓鼠味觉神经切除后的无常现象 用常规的电子显微镜和标记研究进行评估。这个 拟议的标签研究将使用注射霍乱毒素或 用荧光示踪剂确定神经纤维的神经节来源 在之前支配味蕾，或者可能在很久以后支配味蕾， 脊索/舌部去神经。这些研究将提供基本信息 关于神经-味蕾的相互作用。这些研究与一项 了解神经是如何维持味蕾的，他们有 解释永恒性的相对脆弱性的含义 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.