Psychophysical assessment of postgastric chemospecificinfluences on taste

描述（由申请人提供）：肥胖症的流行与过量摄入高热量、美味的食物和液体有关。口腔和肠后化学信号被整合到中枢神经系统中，调节食物和液体的选择，控制食物的大小，并建立味觉偏好。然而，人们对这些信号是如何整合起来改变摄入行为的却知之甚少。由于缺乏探测产后化学感觉信号并将其与摄入行为联系起来的灵敏技术，这方面的进展一直受到阻碍。最近，在胃肠道后细胞中发现了参与味觉转导的化学感受器和相关信号分子（如T1Rs， T2Rs，¿-gustducin），这表明味觉特性可能是在上行后信号中编码的信息之一，并可能直接访问和影响来自口腔的匹配化学感觉信号。考虑到口腔和后食感觉信号以大致平行的途径上升到中枢神经系统，那么特别令人惊讶的是，很少有实验关注后食信号对初级味觉感觉加工的直接影响。因此，一个共同的感觉系统的存在提供了一个框架，用于探测后存储信号对特征良好的味觉引导行为的化学特异性影响。目前的建议寻求支持，开始对大鼠模型的味觉反应的后贮存信号的化学特异性影响的心理物理评估。两种味觉特异性的、互补的行为技术将被用来评估十二指肠内化学物质输注对(a)味觉刺激的享乐评价和(b)味觉刺激的敏感性（独立于刺激的享乐价）的影响。特异性目的1验证了胃后信号影响口腔味觉刺激的享乐评价的假设

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.