The Neurobiology of Sour Taste

描述(申请人提供)：口腔中含有酸性物质会引起酸味。但口咽部酸化不只是由于摄入的物质，还可能是由胃反流引起的，胃反流会引起强烈的呼吸和唾液反射以及恶心的感觉。口腔中的酸性物质不仅触发味觉系统，还激活对pH敏感的一般粘膜神经纤维。以前的研究已经确定了酸味转导所需的味觉细胞亚群，但这些细胞如何将信息传递到味觉神经，从而脑干味觉中继核仍不清楚。对酸反应的粘膜神经纤维也传递有关口腔内pH的信息，并以与酸味纤维部分重叠的方式结束于脑干。本建议中的实验利用行为、药理学、解剖学和生理学方法来检查酸味和非味觉系统在多大程度上有助于检测和避免酸。这些实验依赖于独特的敲除啮齿动物模型来分离这两个口腔内酸反应系统的功能和作用。我们将同时使用药理学和遗传学工具来研究在没有一个系统的情况下，刺激一个系统会激活脑干的哪些区域。

DESCRIPTION (provided by applicant): The presence of acidic substances in the mouth evokes a sensation of sour taste. But oropharyngeal acidification is not only attributable to ingested substances, but may be produced by gastric reflux which evokes strong respiratory and salivary reflexes as well as a sensation of disgust. Acidic substances in the oral cavity not only trigger the taste system but also activate pH-sensitive general mucosal nerve fibers. Previous studies have identified the subset of taste cells necessary for sour transduction, but how these cells transmit the information to the gustatory nerves and thence the brainstem gustatory relay nuclei remains unclear. Acid-responsive mucosal nerve fibers also transmit information about intraoral pH and end within the brainstem in a partially overlapping fashion with the sour taste fibers. Experiments in this proposal utilize behavioral, pharmacological, anatomical and physiological means to examine to what degree the sour taste and non- taste systems contribute to the detection and avoidance of acids. The experiments rely on unique knockout rodent models to dissociate the functions and roles of the two intraoral acid-responsive systems. We will use both pharmacological and genetic tools to study what areas of the brainstem are activated by stimulation of one system in the absence of the other.