A TAS1R receptor-based explanation of sweet 'water-taste'
A TAS1R receptor-based explanation of sweet 'water-taste'
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DOI：
10.1038/nature04765
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发表时间：
2006-05-18
期刊：
影响因子：
64.8
通讯作者：
Breslin, PAS
中科院分区：
文献类型：
--
作者：
Galindo-Cuspinera, V;Winnig, M;Breslin, PAS
“水味”是在从口中去除化学溶液后由水引起的味觉后印象，类似于在彩色图像固定后出现在“白色”纸上的彩色后图像。与彩色后像不同，味觉后效知之甚少（1）。一种理论认为，“水的味道”是适应现象，其中适应一种味道溶液导致随后出现的水作为味觉刺激（2，3）。另一种假设是，在冲洗时去除刺激物会在味觉受体细胞中产生基于受体的正性关闭反应，最终诱导味觉感知（4）。在这里，我们表明，甜的“水的味道”引起甜味抑制剂被冲洗掉。表达人类甜味剂受体的培养细胞的反应与心理物理反应直接平行-水冲洗去除了异聚甜味剂受体TAS 1 R2-TAS 1 R3的抑制剂，这激活了细胞并导致从纯水中感受到强烈的甜味。当两种状态的变构甜味受体上的平衡力导致它们在通过冲洗从抑制释放后协调转变为激活状态时，这种“反弹”活性发生（5-7）。
Water-tastes' are gustatory after-impressions elicited by water following the removal of a chemical solution from the mouth, akin to colour after-images appearing on 'white' paper after fixation on coloured images. Unlike colour after-images, gustatory aftereffects are poorly understood(1). One theory posits that 'water-tastes' are adaptation phenomena, in which adaptation to one taste solution causes the water presented subsequently to act as a taste stimulus(2,3). An alternative hypothesis is that removal of the stimulus upon rinsing generates a receptor-based, positive, off-response in taste-receptor cells, ultimately inducing a gustatory perception(4). Here we show that a sweet 'water-taste' is elicited when sweet-taste inhibitors are rinsed away. Responses of cultured cells expressing the human sweetener receptor directly parallel the psychophysical responses - water rinses remove the inhibitor from the heteromeric sweetener receptor TAS1R2 - TAS1R3, which activates cells and results in the perception of strong sweetness from pure water. This 'rebound' activity occurs when equilibrium forces on the two-state allosteric sweet receptors result in their coordinated shift to the activated state upon being released from inhibition by rinsing(5-7).