Synergistic responses of the chorda tympani to mixtures of umami and sweet substances in rats
Synergistic responses of the chorda tympani to mixtures of umami and sweet substances in rats
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DOI：
10.1093/chemse/28.3.261
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发表时间：
2003-03-01
期刊：
影响因子：
3.5
通讯作者：
Yamamoto, T
中科院分区：
文献类型：
--
作者：
Sako, N;Tokita, K;Yamamoto, T
众所周知，L-谷氨酸一钠 (MSG) 和 5'-肌苷一磷酸 (IMP) 等鲜味物质会在人类体内产生一种称为“鲜味”的独特味道。鲜味的特征之一是协同作用：通过向味精中添加5'-核糖核苷酸而产生的反应幅度的协同增强。除了这种有据可查的协同作用之外，我们通过分析大鼠的鼓索反应，首次报告了谷氨酸受体激动剂 L-AP4 和甜味物质之间的另一种协同作用。结果如下：(i)当L-AP4与一种甜味物质，例如蔗糖、葡萄糖、果糖和麦芽糖混合时，观察到大的协同反应。 (ii)除了L-AP4+蔗糖之外，这些协同反应不被甜味抑制剂、古马林和链霉蛋白酶E抑制。(iii)这些协同反应不被代谢型或离子型谷氨酸受体拮抗剂抑制。 (iv) 对 L-AP4 和甜味物质的二元混合物反应良好的纤维也对 NaCl 和 HCl 反应良好，但对蔗糖反应非常弱。这些发现与谷氨酸和IMP之间的协同作用特征不同。讨论了大鼠味觉细胞鲜味的多种转导机制。
It has been known that umami substances such as monosodium L-glutamate (MSG) and 5'-inosine monophosphate (IMP) elicit a unique taste called 'umami' in humans. One of the characteristics of the umami taste is synergism: the synergistic enhancement of the magnitude of response produced by the addition of 5'-ribonucleotides to MSG. In addition to this well-documented synergism, we report here for the first time on another type of synergism between a glutamate receptor agonist, L-AP4, and sweet substances, by analyzing the chorda tympani responses in rats. The results are as follows: (i) when L-AP4 was mixed with one of the sweet substances, such as sucrose, glucose, fructose and maltose, large synergistic responses were observed. (ii) These synergistic responses, except to L-AP4 + sucrose, were not suppressed by sweet taste suppressants, gurmarin and pronase E. (iii) These synergistic responses were not suppressed by either metabotropic or ionotropic glutamate receptor antagonists. (iv) Fibers that responded well to the binary mixtures of L-AP4 and sweet substances also responded well to NaCl and HCl, but very weakly to sucrose. These findings are different from the characteristics of synergism between glutamate and IMP. The multiple transduction mechanisms for the umami taste in rat taste cells are discussed.