The role of salivary proteins in taste and feeding

唾液蛋白在味觉和进食中的作用

• 批准号: 9172311
• 负责人: Ann-Marie Torregrossa
• 金额: $ 5.16万
• 依托单位: STATE UNIVERSITY OF NEW YORK AT BUFFALO
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9172311
• 关键词: role; salivary; proteins; taste; feeding

DESCRIPTION (provided by applicant): Variation in bitter taste perception may play a key role in diet selection, which has an uncontestable effect on human health. Although bitter compounds are often associated with toxic substances a large number of nutritionally significant food sources contain bitter phytochemicals (e.g., broccoli [1], spinach [2]) many of which can have beneficial value [1, 3] Understanding how bitter taste is perceived and detected is of great importance to understanding diet selection [4] and increasing the acceptability of pediatric medicines [19]. Under normal feeding and drinking conditions taste compounds must inescapably mix with saliva before reaching their receptor targets but very little work has been done examining how salivary proteins modulate taste stimuli and alter bitter taste perception. Seventy percent of all salivary proteins make up a class of proteins referred to as proline-rich proteins (PRPs). PRP production is induced in rats by dietary exposure to tannic acid, a class of plant compounds that animals, including humans, regularly consume. It has been hypothesized that PRPs alter the acceptability of tannic acid by binding to tannins and thereby reduce the perceived intensity of the tannic acid solution [10, 11]. There is evidence to suggest that these proteins may have a similar relationship with other bitters. They are produced in close proximity to bitter taste receptors [13]. Genes for PRPs and bitter taste receptors are interspersed on the same chromosome [5] and lastly, gene linkage studies have implicated a role for PRPs bitter acceptance in humans and mice [15-18]. Specific Aim 1 will establish if long term exposure to bitter compounds can increase the expression of PRPs and establish whether oral exposure is necessary and sufficient to cause induction. Saliva will be analyzed for PRP content before and after exposure to diets adulterated with bitter compounds, including quinine and tannic acid. To isolate the site of exposure necessary for PRP induction rats will also be given tannic acid via either oral or gastric exposure. The ability or inability to induce PRP production is not sufficient to predict interactios between the proteins and the bitter tastants. Therefore, Specific Aim 2 will establish if PRP induction can alter the detection threshold for and superthreshold responsiveness to multiple bitter stimuli. Rats will be used to derive psychophysical detection curves of several bitter tastants in the presence and absence of PRPs. Likewise, responsiveness in the suprathreshold range will be assessed in the presence and absence of PRPs with a series of brief-access tests. Collectively, these experiments will test the hypothesis that PRPs alter taste sensitivity for bittr taste stimuli and ultimately blunt unconditioned taste avoidance responses to these compounds. Together these aims could inform methods for increasing the palatability of healthy phytochemicals and pediatric medicines.

描述（由申请人提供）：苦味感知的变化可能在饮食选择中发挥关键作用，这对人类健康具有无可争议的影响。尽管苦味化合物通常与有毒物质有关，但大量具有营养价值的食物来源都含有苦味植物化学物质（例如西兰花 [1]、菠菜 [2]），其中许多植物化学物质具有有益价值 [1, 3] 了解如何感知和检测苦味对于了解饮食选择 [4] 和提高儿科药物的可接受性 [19] 非常重要。在正常的喂养和饮用条件下，味觉化合物在到达其受体目标之前必须不可避免地与唾液混合，但很少有人研究唾液蛋白如何调节味觉刺激并改变苦味感知。百分之七十的唾液蛋白由一类称为富含脯氨酸蛋白 (PRP) 的蛋白质组成。 PRP 的产生是通过饮食中接触单宁酸来诱导大鼠产生的，单宁酸是包括人类在内的动物经常食用的一类植物化合物。据推测，PRP 通过与单宁结合来改变单宁酸的可接受性，从而降低单宁酸溶液的感知强度 [10, 11]。有证据表明这些蛋白质可能与其他苦味剂具有类似的关系。它们是在靠近苦味受体的地方产生的[13]。 PRP 和苦味受体的基因散布在同一条染色体上 [5]，最后，基因连锁研究表明 PRP 在人类和小鼠中对苦味接受具有一定的作用 [15-18]。 具体目标 1 将确定长期暴露于苦味化合物是否可以增加 PRP 的表达，并确定口服暴露是否是必要且足以引起诱导。在接触含有奎宁和单宁酸等苦味化合物的饮食之前和之后，将对唾液中的 PRP 含量进行分析。为了隔离 PRP 诱导所需的暴露部位，还将通过口服或胃暴露给予大鼠单宁酸。能否诱导 PRP 产生不足以预测蛋白质与促苦味剂之间的相互作用。因此，具体目标 2 将确定 PRP 诱导是否可以改变对多种苦味刺激的检测阈值和超阈值反应。将使用大鼠来得出在存在和不存在 PRP 的情况下几种苦味促味剂的心理物理检测曲线。同样，在存在和不存在 PRP 的情况下，将通过一系列简短的访问测试来评估阈上范围内的反应能力。总的来说，这些实验将检验以下假设：PRP 会改变苦味刺激的味觉敏感性，并最终减弱对这些化合物的无条件味觉回避反应。这些目标共同可为提高健康植物化学物质和儿科药物的适口性提供方法。