Behavioral comparisons of the tastes of L-alanine and monosodium glutamate in rats.
Behavioral comparisons of the tastes of L-alanine and monosodium glutamate in rats.
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大鼠L-丙氨酸和味精味道的行为比较。
DOI：
10.1093/chemse/bjh246
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
Delay,EugeneR
中科院分区：
文献类型：
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作者：
Taylor-Burds,CarolC;Westburg,AnnaM;Wifall,TimothyC;Delay,EugeneR
最近的研究表明 T1R1/T1R3 是哺乳动物中检测 l-氨基酸（包括 l-谷氨酸钠 (MSG) 和 l-丙氨酸）的主要味觉受体。之前对啮齿动物的行为研究只发现很少的证据表明这两种物质具有共同的感知品质，但这些研究没有控制与味精相关的钠的味道。这项研究使用多种行为方法来比较大鼠对味精和l-丙氨酸的感知质量，使用阿米洛利（一种钠通道阻滞剂）来减少味精味道中的钠成分。添加或不添加阿米洛利时，大鼠中 1-丙氨酸的检测阈值范围为 0.4 至 2.5 mM，这与味精的阈值估计值相似。条件性味觉厌恶（CTA）发现，当与阿米洛利混合时，大鼠在味精和l-丙氨酸之间表现出强烈的CTA交叉泛化，表明这两种物质具有相似的感知品质。辨别方法表明，除非钠的提示功能减弱，否则大鼠很容易辨别l-丙氨酸和味精。当阿米洛利添加到所有刺激物中时，在浓度<100 mM时，辨别变得更加困难，并且当还添加氯化钠以匹配味精的钠浓度时，辨别变得更加困难。这些结果表明，在感知上，味精和 1-丙氨酸具有非常相似的味道品质，并支持这两种氨基酸激活共同味觉受体的假设。知觉质量的差异还表明也可能涉及一种或两种物质的单独传入处理。
Recent research has implicated T1R1/T1R3 as the primary taste receptor in mammals for detectingl-amino acids, includingl-monosodium glutamate (MSG) andl-alanine. Previous behavioral studies with rodents found only minimal evidence that these two substances share perceptual qualities, but those studies did not control for the taste of sodium associated with MSG. This study used several behavioral methods to compare the perceptual qualities of MSG andl-alanine in rats, using amiloride (a sodium channel blocker) to reduce the sodium component of MSG taste. Detection thresholds ofl-alanine in rats ranged between 0.4 and 2.5 mM, with or without amiloride added, which are similar to threshold estimates for MSG. Conditioned taste aversion (CTA) found that rats showed strong cross-generalization of CTA between MSG andl-alanine when mixed with amiloride, indicating the two substances have similar perceptual qualities. Discrimination methods showed that rats easily discriminated betweenl-alanine and MSG unless the cue function of sodium was reduced. The discrimination became significantly more difficult at concentrations <100 mM when amiloride was added to all stimuli and became even more difficult when NaCl was also added tol-alanine solutions to match the sodium concentrations of MSG. These results indicate that, perceptually, MSG andl-alanine have quite similar taste qualities and support the hypothesis that these twol-amino acids activate a common taste receptor. The differences in perceptual qualities also suggest separate afferent processing of one or both substances may also be involved.