Taste receptors for umami: the case for multiple receptors
Taste receptors for umami: the case for multiple receptors
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DOI：
10.3945/ajcn.2009.27462h
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发表时间：
2009-09-01
影响因子：
7.1
通讯作者：
Roper, Stephen D.
中科院分区：
文献类型：
--
作者：
Chaudhari, Nirupa;Pereira, Elizabeth;Roper, Stephen D.
鲜味是由许多小分子引起的，包括氨基酸（谷氨酸和天冬氨酸）和核苷酸（肌苷酸或鸟苷酸的单磷酸、肌苷5 '-单磷酸和鸟苷-5'-单磷酸）。哺乳动物的味蕾通过膜受体对这些不同的化合物做出反应，这些膜受体结合了鲜味剂。在过去的15年里，已经提出了几种受体来支持味蕾中的鲜味检测。这些受体包括2种谷氨酸选择性G蛋白偶联受体mGluR 4和mGluR 1，以及味蕾表达的异源二聚体T1 R1 + T1 R3。这些受体中的每一种都在前部和后部味蕾的少量细胞中表达。mGluRs被谷氨酸和某些类似物激活，但没有报道对核苷酸敏感。相比之下，T1 R1 + T1 R3被广泛的氨基酸激活，并在核苷酸存在下显示出强烈增强的反应。Grm 4基因被敲除的小鼠显示出对鲜味促味剂的极大增强的偏好。据报道，Tas 1 R1或Tas 1 R3基因的缺失会抑制但不会消除对鲜味的神经和行为反应。当完整的哺乳动物味蕾顶部刺激的鲜味促味剂，它们的功能反应的鲜味促味剂不完全类似于一个单一的建议鲜味受体的反应。此外，对鲜味剂的反应持续存在于T1 R3敲除小鼠的味觉细胞中。因此，鲜味检测可能涉及在不同的味觉细胞亚群中表达的多种受体。这种受体的多样性可能是鲜味的复杂感知的基础，氨基酸、肽和核苷酸的不同混合物产生微妙的不同味道品质。美国临床营养杂志2009; 90（增刊）：738 S-42 S。
Umami taste is elicited by many small molecules, including amino acids ( glutamate and aspartate) and nucleotides (monophosphates of inosinate or guanylate, inosine 5'-monophosphate and guanosine-5'-monophosphate). Mammalian taste buds respond to these diverse compounds via membrane receptors that bind the umami tastants. Over the past 15 y, several receptors have been proposed to underlie umami detection in taste buds. These receptors include 2 glutamate-selective G protein-coupled receptors, mGluR4 and mGluR1, and the taste bud-expressed heterodimer T1R1+T1R3. Each of these receptors is expressed in small numbers of cells in anterior and posterior taste buds. The mGluRs are activated by glutamate and certain analogs but are not reported to be sensitive to nucleotides. In contrast, T1R1+T1R3 is activated by a broad range of amino acids and displays a strongly potentiated response in the presence of nucleotides. Mice in which the Grm4 gene is knocked out show a greatly enhanced preference for umami tastants. Loss of the Tas1r1 or Tas1R3 genes is reported to depress but not eliminate neural and behavioral responses to umami. When intact mammalian taste buds are apically stimulated with umami tastants, their functional responses to umami tastants do not fully resemble the responses of a single proposed umami receptor. Furthermore, the responses to umami tastants persist in the taste cells of T1R3-knockout mice. Thus, umami taste detection may involve multiple receptors expressed in different subsets of taste cells. This receptor diversity may underlie the complex perception of umami, with different mixtures of amino acids, peptides, and nucleotides yielding subtly distinct taste qualities. Am J Clin Nutr 2009; 90(suppl): 738S-42S.