Behavioral discrimination between sucrose and other natural sweeteners in mice: Implications for the neural coding of T1R Ligands
Behavioral discrimination between sucrose and other natural sweeteners in mice: Implications for the neural coding of T1R Ligands
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DOI：
10.1523/jneurosci.1227-07.2007
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发表时间：
2007-10-17
影响因子：
5.3
通讯作者：
Spector, Alan C.
中科院分区：
文献类型：
--
作者：
Dotson, Cedrick D.;Spector, Alan C.
在味蕾细胞中，两种不同的 T1R 异聚味觉受体介导糖（典型的“甜味”味觉受体，T1R2 + T1R3）和 L-氨基酸（T1R1 + T1R3 受体）的信号转导。 T1R1 + T1R3 受体被认为介导第五种基本味觉品质“鲜味”。然而，L-氨基酸的一个子集对于人类来说是“甜味的”，对于非人类哺乳动物来说似乎具有“蔗糖样”的味道品质。这表明，所有这些化合物在不同程度上都激活了一个神经通道，从而导致了甜味的感知。这里详细介绍的实验旨在测试小鼠在操作味觉辨别任务中区分蔗糖和各种其他糖和 L-氨基酸的能力。小鼠在区分蔗糖、L-丝氨酸、L-苏氨酸、麦芽糖、果糖和葡萄糖时至少有些困难。例如，当考虑浓度效应时，小鼠很难区分蔗糖和葡萄糖或果糖，以及较小程度的麦芽糖，这表明糖产生单一的感知质量。然而，小鼠能够可靠地区分蔗糖、L-丝氨酸和L-苏氨酸。使用条件性味觉厌恶测定收集的数据还表明，虽然在质量上与蔗糖的味道相似，但 L-丝氨酸和 L-苏氨酸会产生独特的感知。总之，来自与糖和一些 L-氨基酸结合的味觉受体蛋白的一些信号似乎沿着味觉神经轴的某处汇聚。然而，这些实验的结果也意味着甜味 L-氨基酸可能具有与典型甜味剂蔗糖不同的定性味道特征。
In taste bud cells, two different T1R heteromeric taste receptors mediate signal transduction of sugars (the canonical "sweet" taste receptor, T1R2 + T1R3) and L-amino acids (the T1R1 + T1R3 receptor). The T1R1 + T1R3 receptor is thought to mediate what is considered the fifth basic taste quality "umami." However, a subset of L-amino acids is "sweet tasting" to humans and appears to possess a "sucrose-like" taste quality to nonhuman mammals. This suggests, to varying degrees, that all of these compounds activate a single neural channel that leads to the perception of sweetness.The experiments detailed here were designed to test the ability of mice to distinguish between sucrose and various others sugars and L-amino acids in operant taste discrimination tasks. Mice had at least some difficulty discriminating sucrose from L-serine, L-threonine, maltose, fructose, and glucose. For example, when concentration effects are taken into consideration, mice discriminated poorly, if at all, sucrose from glucose or fructose and, to a lesser extent maltose, suggesting that sugars generate a unitary perceptual quality. However, mice were able to reliably discriminate sucrose from L-serine and L-threonine. Data gathered using a conditioned taste aversion assay also suggest that, although qualitatively similar to the taste of sucrose, L-serine and L-threonine generate distinctive percepts. In conclusion, it appears that some signals from taste receptor proteins binding with sugars and some L-amino acids converge somewhere along the gustatory neuraxis. However, the results of these experiments also imply that sweet-tasting L-amino acids may possess qualitative taste characteristics that are distinguishable from the prototypical sweetener sucrose.