Ribonucleotide monophosphates and umami taste

描述(由申请人提供)：这项资助将定义5‘核糖核酸一磷酸、肌苷一磷酸(IMP)和鸟苷一磷酸(GMP)的一些味道品质，这些都是用于研究“鲜味”味道的重要物质。味觉对于确定食物来源、维持营养平衡和避免有害物质是很重要的。谷氨酸单钠(MSG)是一种天然存在的氨基酸，存在于许多富含蛋白质的食物中，如肉类、奶酪和一些蔬菜。有机体检测谷氨酸的能力很重要，因为它的味道是食物蛋白质存在的信号，它可以增加食物的适口性，从而增加食物的摄入量。谷氨酸和其他几种L氨基酸具有两种决定性的味道特征。它的一种品质是它独特的味道，被称为“umami”，被认为与甜、酸、咸和苦不同。Umami物质的第二个定义性质是它们与IMP和GMP协同作用的能力。令人惊讶的是，尽管这种协同作用一直是并将继续是研究鲜味的关键，但我们对IMP和GMP的感知特征的理解是有限的，几乎总是与味精或其他氨基酸的研究交织在一起。这些限制提出了两个基本问题，这也是这项资助的具体目的：(1)行为上，大鼠对IMP和GMP有多敏感，(2)这些物质与激活鲜味感受器的氨基酸具有相同的味道品质吗？一般认为IMP和GMP具有与味精相同的鲜味，但有数据表明，与其他鲜味物质相比，IMP和GMP可能具有不同的味道。建议进行行为实验，以解决赠款的具体目标。首先，将进行实验，确定大鼠对IMP和GMP的检测阈值，使用标准的心理物理方法。其次，将进行味觉辨别实验，迫使大鼠检测两种味道物质之间的感知差异，以表征IMP和GMP的味道品质，并确定这些品质是否与味精和其他氨基酸区分开来。具体来说，辨别实验将决定老鼠是否能够辨别IMP、GMP、味精和其他具有鲜味的氨基酸的味道。如果IMP和GMP具有相同的味道品质，并且这些品质与味精和其他“鲜味”物质相同。

DESCRIPTION (provided by applicant): This grant will define some of the taste qualities of the 5' ribonucleotide monophosphates, inosine monophosphate (IMP) and guanosine monophosphate (GMP) that are important substances used to study "umami" taste. The sense of taste is important for locating food sources, maintaining nutritional equilibrium and avoiding harmful substances. Monosodium glutamate (MSG) is a naturally occurring amino acid present in many protein-rich foods such as meats, cheese, and some vegetables. The ability of an organism to detect glutamate is important because its taste signals the presence of dietary protein, and it can increase the palatability of food and, thus, food intake. Glutamate and several other L-amino acids possess two defining taste qualities. One quality is its unique taste called "umami" that is thought to be distinct from sweet, sour, salty, and bitter. A second defining quality of umami substances is their ability to interact synergistically with IMP and GMP. Surprisingly, even though this synergistic interaction has been and will continue to be key to the study of umami taste, our understanding of the perceptual characteristics of IMP and GMP is limited and almost always intertwined with the study of MSG or other amino acids. These limitations raise two fundamental questions that are the specific aims of this grant: (1) behaviorally how sensitive are rats to IMP and GMP, and (2) do these substances have the same taste qualities as the amino acids that activate umami taste receptors? It is generally assumed that IMP and GMP have an umami taste identical to MSG but there are data suggesting IMP and GMP may possess different taste qualities compared to other umami substances. Behavioral experiments are proposed that address the grant's specific aims. First, experiments will be conducted to determine the detection thresholds for IMP and GMP in rats using standard psychophysical methods. Second, taste discrimination experiments in which rats are forced to detect perceptual differences between two taste substances will be conducted to characterize the taste qualities of IMP and GMP, and to determine if these qualities are distinguishable from MSG and other amino acids. Specifically discrimination experiments will determine whether rats can discriminate between the tastes of IMP, GMP, MSG, and other amino acids with an umami taste. If IMP and GMP have identical taste qualities, and these qualities are the same as MSG and the other "umami" substance.