GUSTATORY NST--PATHWAYS, SYNAPSES AND NEUROCHEMICALS

孤束吻端核细胞类型的研究 (NST)它们的连接和突触关系对于 了解哺乳动物味觉系统的基本结构。 这些研究的一个主要目标是为这些人开发一个写作图表。 味觉NST，其中不同成分之间的连接是 基于它们的形态在突触水平上鉴定， 它们的原始细胞和它们的神经化学物质或神经递质 特色 提供有关突触组织的信息 在吻侧NST的电路是有限的。 拟议的研究将提供有关 NST的形态学和神经化学组织， 关于其神经元结构和突触组织的最新发现 在仓鼠身上 传入轴突之间的突触相互作用， 投射神经元和含γ-氨基丁酸（GABA能） 将通过电子显微镜结合 轴突和细胞标记方法和免疫细胞化学。 的 方法涉及一系列的标签研究，重点是吻侧 NST的中央分区。 此区域接收denial输入 来自味觉初级传入轴突，包含大部分臂旁神经 （PBN）-投射细胞和许多GABA能细胞。 Axon终端将 用辣根过氧化物酶（HRP）或霍乱毒素（Ct）标记， 神经化学成分（例如GABA），或使用顺行性 退化 在某些材料中，将使用第二个对比标签 根据连接（HRP或CT）证明细胞类型，或 化学特性（如GABA）。 这些研究将决定 味觉传入轴突是否与PBN投射细胞突触， 髓内投射细胞或GABA能中间神经元。 来自不同传入轴突的输入的会聚（例如，索 鼓膜和舌咽神经）对所鉴定的细胞类型的影响将被 评估。 下行轴突的精细结构和突触部位 从前脑和轴突特征免疫细胞化学（例如， GABA）也将被确定。 这些研究的数据应该允许 关于孤核的电路如何 处理和传播味觉信息。 知识 味觉系统的微电路需要更完整的 味觉障碍的理解及其进展。

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.