BRAINSTEM GUSTATORY PROCESSING

描述（改编自研究者摘要）：解剖学， 味觉和内脏的电生理和药理学数据 通路提出了几个可检验的假说， 孤束核（NST）的组织。 PI的 实验室已经表明，NST中的味觉细胞是由外周驱动的， 味觉纤维通过兴奋性氨基酸，这些细胞是紧张性的 GABA抑制，NST中的味觉反应细胞兴奋， 有时被神经肽P物质抑制。 应用程序将通过解决三个具体目标来扩展这些调查结果。 第一，NST的抑制机制及其在形成NST中的作用。 味觉神经元的反应性将被进一步研究。 初始 实验将确定GABAB和甘氨酸受体是否有助于 抑制在NST，如果抑制锐化调谐的广度， NST神经元对味觉刺激的反应。 进一步的实验将确定， 味觉神经元之间的抑制控制存在差异， 将信息传递到臂旁核（中继神经元）， 非中继神经元（nonrelay neurons） 第二个目标是确定 来自味觉新皮层和中央核的下行输入 杏仁核对NST味觉神经元的影响。 最初的实验将检查 假设来自新皮层和杏仁核的下行输入产生了 NST细胞的兴奋性和抑制性调节。 随后的实验 将测试兴奋性输入是由 兴奋性氨基酸和抑制性氨基酸的抑制性输入。 这一目标的最后一组实验将评估以下假设： 与非中继神经元相比，中继神经元受到中枢输入的调制不同 神经元 最后一个具体目标将解决调制的问题， NST味觉反应的神经肽，特别是，明显的 P物质对NaCl-最佳神经元的优先兴奋作用。 甲硫氨酸脑啡肽对NST味觉神经元的作用及其可能的差异调节 神经肽对中继和非中继神经元的影响也将被检查。 这些体内实验旨在揭示突触是如何 NST中的相互作用以及与该核控制的连接 NST神经元对味觉输入的反应。 这些研究将提供 重要的新信息，我们了解的功能 中央味觉系统的组织。

DESCRIPTION (Adapted from investigator's abstract): Anatomical, electrophysiological and pharmacological data on gustatory and visceral pathways suggest several testable hypotheses about the functional organization of the nucleus of the solitary tract (NST). The PI's laboratory has shown that taste cells in the NST are driven by peripheral taste fibers via excitatory amino acids, that these cells are tonically inhibited by GABA and that taste-responsive cells in the NST are excited and sometimes inhibited by the neuropeptide, substance P. The current application will extend these findings by addressing three specific aims. First, the mechanisms of inhibition in the NST and its role in shaping the responsiveness of gustatory neurons will be further investigated. Initial experiments will determine if GABAB and glycine receptors contribute to inhibition in the NST and if inhibition sharpens the breadth of tuning of NST neurons to gustatory stimuli. Additional experiments will determine if there are differences in inhibitory control between gustator neurons that relay information to the parabrachial nuclei (relay neurons) and those that do not (nonrelay neurons). The second aim is to determine the influence of descending inputs from the gustatory neocortex and the central nucleus of the amygdala on NST taste neurons. Initial experiments will examine the hypothesis that descending inputs from the neocortex and amygdala produce excitatory and inhibitory modulation of NST cells. Subsequent experiments will test the hypotheses that the excitatory inputs are mediated by excitatory amin acids and the inhibitory inputs by inhibitory amino acids. The final set of experiments in this aim will evaluate the hypothesis that relay neurons are modulated differently by central inputs than nonrelay neurons. The final specific aim will address the question of modulation of NST taste responses by neuropeptides, and in particular, the apparent preferential excitation of NaCl-best neurons by substance P. The effects of met-enkephalin on NST taste neurons and the possible differential modulation of neuropeptide effects on relay and nonrelay neurons will also be examined. These in vivo experiments ar designed to reveal how the synaptic interactions in the NST and the connection to and from this nucleus control responses of NST neurons to gustatory inputs. These studies will provide important new information for our understanding of the functional organization of the central gustatory system.