Neural Plasticity in the Adult Gustatory System

描述（由申请人提供）：味蕾对神经支配的依赖性已被用作理解神经/焦油相互作用的模型。神经支配的丧失导致味蕾正常形态外观的丧失，而神经支配的恢复导致味蕾形态和功能的恢复。成人再生的味觉系统特别容易受到环境操纵的影响。结合单侧鼓室索神经切断术和低钠饮食对成年大鼠的味蕾和再生神经产生多种功能和解剖改变。此外，功能和解剖学上的改变也发生在完整的舌对侧。除了与鼓室索神经外周部分相关的损伤引起的影响外，也有极端的形态学变化涉及到被切片的神经的中心部分。协调研究将利用单侧鼓室索神经切断术和饮食钠限制联合引起的显著功能和解剖可塑性。一个系统水平的方法将集中在神经可塑性在成年大鼠的味觉系统。结合解剖学、神经生理学、电子显微镜和免疫细胞化学技术，将允许确定：1)正常成人单个味蕾神经支配随时间的稳定性，并确定耳脊索神经元对其原始目标的再神经支配的准确性；2) NTS终端场塑性的程度和性质；3) NTS突触可塑性的程度和性质；4)单侧鼓室索神经切断和/或饮食钠限制对NTS味觉反应的功能影响。这些研究的结果将涉及更广泛的主题：感觉编码，神经活动在维持感觉功能中的作用，以及正常情况下和神经损伤反应下外周神经支配的时间稳定性和准确性。结果也将使更清楚地了解人类味觉神经损伤的神经生物学后遗症病理持续，或在中耳或口腔手术。

DESCRIPTION (provided by applicant): The dependence of taste buds on innervation has been used as a model to understand nerve/tar interactions. Loss of innervation results in a loss of the normal morphological appearance of taste buds, while restoration of innervation results in a recovery of taste bud morphology and function. The adult regenerating gustatory system is especially susceptible to environmental manipulations. Combining unilateral chorda tympani nerve section and low sodium diet in adult rats results in a variety of functional and anatomical alterations in both taste buds and in the regenerating nerve. Furthermore, functional and anatomical alterations also occur in the intact, contralateral side of the tongue. In addition to injury-induced effects related to the peripheral portion of the chorda tympani nerve, there are also extreme morphological changes that involve the central portion of the sectioned nerve. Coordinated studies will take advantage of the remarkable functional and anatomical plasticity induced by combined unilateral chorda tympani nerve section and dietary sodium restriction. A systems-level approach will focus on neural plasticity in the adult rat gustatory system. Combined anatomical, neurophysiological, electron microscopic, and immunocytochemical techniques will permit a determination of: 1) the stability of innervation of single taste buds over time in normal adults and determine the accuracy of chorda tympani neurons in reinnervating their original targets; 2) the extent and nature of terminal field plasticity in the NTS; 3) the extent and nature of synaptic plasticity in the NTS; and 4) the functional consequences of unilateral chorda tympani nerve section and/or dietary sodium restriction on taste responses in the NTS. Findings from these studies will address the broader topics of sensory coding, the role of neural activity in maintenance of sensory function, and the temporal stability and accuracy of peripheral innervation under normal circumstances and in response to nerve damage. Results will also enable a clearer understanding of the neurobiological sequelae of human taste nerve damage sustained pathologically, or during middle ear or oral surgery.