STRUCTURE-FUNCTION RELATIONSHIP OF BRAINSTEM TASTE CELLS

与现有的大量关于 视觉、躯体感觉和听觉的发展和组织 我们对中枢神经系统的作用知之甚少 系统的味觉。本提案中描述的实验是 旨在提供数据， 对味觉功能的理解。拟议的研究是基于 以下三个假设：1）形态学定义的细胞类型 大鼠孤束核（NST）的反应不同， NST神经元的树突状突触结构 反映了这些细胞的反应特性; 3）味觉的变化 发育过程中的敏感性与特定的 NST的形态变化（这一假设将在 完成成年动物的研究）。我们将首先讨论 通过标记个体生理特征NST的假设 在成年大鼠的味觉神经元细胞内注射 辣根过氧化物酶（HRP）。利用计算机三维 重建技术，我们将每个神经元的形态 性状与其生理反应特性。第二个假设 将通过确定突触前末梢的密度来解决 成年味觉神经元的树突。单个NST神经元将 用HRP标记并处理用于电子显微镜。阶层 第一，第二和第三级树突将被重建， 三个维度和突触的类型，位置和数量将被 确定。我们将开始通过使用 出生后10日龄动物的细胞内标记技术 （允许未成熟和成年NST之间的最佳对比）。 在拟议的资助期结束时，我们预计 描述了生理定义的形态特征， NST中的细胞类型。此外，我们还将描述 这些细胞的树突突触学。最后，我们将开始 确定形态变化之间的关系， NST神经元在发育中的生理学。

In contrast to the abundance of information available regarding the development and organization of the visual, somatosensory and auditory systems, we know relatively little about the role of the central nervous system in gustation. The experiments described in this proposal are designed to provide data that will significantly improve our understanding of gustatory function. The proposed studies are based on the following three hypotheses: 1) Morphologically defined cell types of the rat nucleus of the solitary tract (NST) differ in their response properties; 2) The dendritic synaptic architecture of NST neurons reflects the response properties of these cells; 3) Changes in gustatory sensibility during development are correlated with specific morphological changes in the NST (this hypothesis will be addressed upon the completion of studies in adult animals). We will address the first hypothesis by labeling individual physiologically-characterized NST gustatory neurons in the adult rat with the intracellular injection of horseradish peroxidase (HRP). Using computerized three dimensional reconstruction techniques, we will correlate each neuron's morphological traits with its physiological response properties. The second hypothesis will be addressed by determining the density of presynaptic terminals on the dendrites of adult gustatory neurons. Individual NST neurons will be labeled with HRP and processed for electron microscopy. Segments of the first-, second-, and third-order dendrites will be reconstructed in three dimensions and the type, location and number of synapses will be ascertained. We will begin to test the third hypothesis by employing the intracellular labeling technique in postnatal animals aged 10 days (permitting optimal contrast between the immature and adult NST). At the conclusion of the proposed funding period, we expect to have described the morphological characteristics of physiologically-defined cell types in the NST. In addition, we will have characterized the dendritic synaptology of these cells. Finally, we will have begun to determine the relationship between changes in the morphology and physiology of NST neurons in developing animals.