GUSTATORY NST--PATHWAYS, SYNAPSES AND NEUROCHEMICALS

孤束吻侧核细胞类型的研究 (NST)，它们的联系和突触关系，对于 了解哺乳动物味觉系统的基本组织。 这类研究的一个主要目标是为 味觉NST，其中不同组件之间的连接是 根据它们的形态在突触水平上进行识别， 它们的起源细胞及其神经化学或神经递质 特点。介绍有关突触组织的信息 NST顶部的电路是有限的。 拟议的研究将提供有关 NST的形态和神经化学组织 关于其神经元结构和突触组织的最新发现 在仓鼠里。传入轴突之间的突触相互作用， 投射神经元与含γ-氨基丁酸(GABA能) 中间神经元将通过电子显微镜结合 轴突和细胞标记方法及免疫细胞化学。这个 该方法涉及一系列侧重于吻部的标记研究 NST的中央分区。这一地区接受的输入最密集 来自味觉初级传入轴突，并含有大部分臂旁神经 (PBN)-投射细胞和许多GABA能细胞。轴突终末将是 辣根过氧化物酶(HRP)或霍乱毒素(Ct)标记，用于 神经化学含量(如GABA)，或使用顺行识别 退化。在某些材料中，会使用对比标签 根据连接(HRP或CT)演示细胞类型或 化学特性(例如，GABA)。这些研究将确定 味觉传入轴突是否与PBN投射细胞突触 髓内投射细胞，或带有GABA能中间神经元。 来自不同传入轴突(例如，脊索)的输入会聚 鼓室和舌咽神经)上已确定的细胞类型 已评估。轴突下行突触的精细结构和位置 来自前脑和轴突的免疫细胞化学特征(例如 GABA)也将被确定。来自这些研究的数据应该允许 关于孤立核回路如何形成的假说 处理和传播味觉信息。了解以下内容 需要味觉系统的微电路才能更完整 对味觉障碍及其进展的理解。

Studies of the cell types of the rostral nucleus of the solitary tract (NST), their connections and synaptic relationships, are essential for understanding the basic organization of the mammalian gustatory system. A major goal of such studies is to develop a writing diagram for the gustatory NST in which connections between different components are identified at the synaptic level on the basis of their morphologies, their cells of origin and their neurochemical or neurotransmitter characteristics. Present information about the organization of synaptic circuits in the rostral NST is limited. The proposed research will provide detailed information about the morphological and neurochemical organization of the NST in light of recent findings on its neuronal architecture and synaptic organization in the hamster. The synaptic interactions between afferent axons, projection neurons and Gamma aminobutyric acid-containing (GABAergic) interneurons will be characterized by electron microscopy combined with axonal and cellular labelling methods and immunocytochemistry. The approach involves a series of labelling studies focused on the rostral central subdivision of the NST. This region receives the densest input from gustatory primary afferent axons and contains most of parabrachial (PBN)-projection cells an many GABAergic cells. Axon terminals will be labelled with horseradish peroxidase (HRP) or cholera toxin (Ct), for neurochemical content (e.g. GABA), or identified using anterograde degeneration. In some material a second, contrasting label will be used to demonstrate cell types on the basis of connections (HRP or CT) or chemical characteristics (e.g. GABA). These studies will determine whether taste afferent axons synapse with PBN-projection cells, with intramedullary projection cells, or with GABAergic interneurons. Convergence of inputs from different afferent axons (e.g. the chorda tympani and the glossopharyngeal nerve) on identified cell types will be evaluated. The fine structure and sites of synapsis of axons descending from the forebrain and axons characterized immunocytochemically (e.g. for GABA) will also be determined. Data from these studies should allow the formulation of hypotheses about how the circuitry of the solitary nucleus processes and disseminates gustatory information. Knowledge of the microcircuitry of the gustatory system is required for more complete understanding of taste disorders and their progress.