STRUCTURE/FUNCTION RELATIONSHIP OF BRAINSTEM TASTE CELLS

与可获得的关于 视觉、体感和听觉的发展和组织 系统，我们对中枢神经系统的作用知之甚少 系统已进入味觉。本提案中描述的实验包括 旨在提供的数据将显著改善我们的 对味觉功能的理解。建议的研究是基于 以下三个假设：1)形态上定义的细胞类型 大鼠孤束核(NST)的反应不同 2)NST神经元的树突突触构筑 反映这些细胞的反应特性；3)味觉的变化 发展过程中的敏感度与特定的 NST的形态变化(这一假说将在 在成年动物身上完成研究)。我们将解决第一个问题 通过标记个体生理特征的NST的假说 成年大鼠嗅觉神经元胞内注射 辣根过氧化物酶(HRP)。使用计算机化的三维 重建技术，我们将关联每个神经元的形态 特征及其生理反应特性。第二个假设 将通过确定突触前终末在 成年味觉神经元的树突。单个NST神经元将是 用辣根过氧化物酶标记并加工成电子显微镜。的片段 一次、二次和三次枝晶将在 三维空间和突触的类型、位置和数量 已经确定了。我们将通过使用 出生后10日龄动物的细胞内标记技术 (允许未成熟的NST和成年NST之间的最佳对比)。 在拟议的资助期结束时，我们预计将有 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。最后，我们将开始 确定形态上的变化与 发育中动物NST神经元的生理学。

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.