Psychophysical assessment of postgastric chemospecificinfluences on taste

描述(申请人提供)：肥胖症流行与过量摄入卡路里密集、可口的食物和液体有关。中枢神经系统整合了口腔和餐后化学信号，以调整食物和液体的选择，控制食物的大小，并建立口味偏好。然而，关于这些信号是如何整合到一起来改变摄入行为的，人们知之甚少。由于缺乏可用的敏感技术来探测产后化学感觉信号并将这些信号与摄入行为联系起来，这一进展受到了阻碍。最近，在后胃肠道细胞中发现了参与味觉转导的化学受体和相关信号分子(如T1Rs、T2Rs、Gustducin)，这表明味觉特性可能是上升后信号中编码的信息之一，可能直接访问和影响来自口腔的匹配化学感觉信号。考虑到口腔和味后感觉信号大致平行地上升到中枢神经系统，特别令人惊讶的是，很少有人在实验上注意到口感和味后信号对初级味觉加工的直接影响。因此，共同感觉系统的存在为探索后信号对特征良好的味觉引导行为的化学特异性影响提供了一个框架。本提案寻求支持，以开始在大鼠模型中对后遗症信号对味觉反应的化学特异性影响的心理物理评估。将使用两种味觉特定的和互补的行为技术来评估十二指肠内注入化学物质对(A)对口腔味觉刺激的享乐性评估和(B)对口腔味觉刺激的敏感性(与刺激的享乐性价无关)的影响。特定目标1测试了胃后信号影响口腔味觉刺激享乐性评估的假设 在味觉反应试验中的化学特异化方式。特定目的2在两个反应操作型味觉信号检测任务中以化学特异性的方式检验胃后信号影响口腔味觉敏感性的假设。应用这些心理物理技术不仅将识别新的、潜在的重要类型的初级感觉整合，它还将 为我提供新的行为方法和数据分析(例如心理测量功能)方面的培训，并让我接触到以味觉功能为中心的概念专业知识的新领域。这种通过GI味觉信号对口腔味觉加工的特定影响进行的心理物理测试将指导未来对潜在神经机制的研究，最终目标是确定潜在的目标和策略，以增强对控制食物摄入量至关重要的感觉反馈。

DESCRIPTION (provided by applicant): The obesity epidemic is associated with excessive intake of calorie dense, palatable foods and fluids. Oral and postoral chemical signals are integrated in the central nervous system to adjust food and fluid selection, control meal size, and establish taste preferences. Yet little is known about precisely how these signals are integrated to change intake behavior. Progress has been hampered by the lack of available sensitive techniques that probe postoral chemosensory signals and link those to intake behaviors. Recently, chemoreceptors and associated signaling molecules involved in taste transduction (e.g., T1Rs, T2Rs, ¿ -gustducin) have been discovered in postoral GI cells, suggesting the interesting possibility that taste properties are among the information encoded in ascending postoral signals and may directly access and impact matching chemosensory signals arising from the oral cavity. Considering oral and postoral sensory signals ascend the central nervous system in roughly parallel pathways, it is especially surprising then that very little experimental attention has been paid to direct influence of postoral signals on primary taste sensory processing. As such, the presence of a common sensory system provides a framework for probing chemospecific influences of postoral signals on well characterized taste-guided behaviors. The present proposal seeks support to begin the psychophysical assessment of chemospecific influences of postoral signals on taste responsiveness in a rat model. Two taste-specific, and complementary, behavioral techniques will be used to assess the effects of intraduodenal chemical infusions on (a) hedonic evaluation of and (b) sensitivity to, independent of the hedonic valence of the stimulus, an oral taste stimulus. Specific Aim 1 tests the hypothesis that postgastric signals influence the hedonic evaluation of an oral taste stimulus in a chemospecific manner in the taste reactivity test. Specific Aim 2 tests the hypothesis that postgastric signals influence oral taste sensitivity in a chemospecific manner in the two response operant taste signal detection task. Not only will applying these psychophysical techniques identify novel, and potentially, important types of primary sensory integration, it will afford me training in new behavioral approaches and data analyses (e.g., psychometric functions) and expose me to a new area of conceptual expertise centered on gustatory function. Such psychophysical testing of GI taste signals through their specific impact on oral taste processing will direct future work on the underlying neural mechanisms, with the ultimate goal of identifying potential targets and strategies to augment sensory feedback crucial to the control of food intake.