Responses to umami substances in taste bud cells innervated by the chorda tympani and glossopharyngeal nerves
Responses to umami substances in taste bud cells innervated by the chorda tympani and glossopharyngeal nerves
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DOI：
10.1093/jn/130.4.950s
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发表时间：
2000-04-01
影响因子：
4.2
通讯作者：
Hellekant, G
中科院分区：
文献类型：
--
作者：
Ninomiya, Y;Nakashima, K;Hellekant, G
几种哺乳动物的鼓索（GT）和舌咽（GL）神经对鲜味物质（US）如谷氨酸二钠（MSG）、5 '-肌苷酸二钠（IMP）和5'-鸟苷酸二钠（GMP）的反应不同。在小鼠和恒河猴中，GL神经对US的反应大于CT神经，GL神经含有更多的MSG敏感纤维。甜味反应抑制剂Gurmarin抑制小鼠对MSG和IMP混合物的CT反应，使其接近对照水平的65%，但对代谢型和离子型谷氨酸激动剂2-氨基-4-磷酸丁酸和N-甲基-D-天冬氨酸没有抑制作用。Gurmarin不会抑制GL中的任何味觉反应。在小鼠中，CT对MSG的反应可能被其对钠离子的更高敏感性所掩盖。钙成像研究表明，从CT支配的菌状乳头分离的一些小鼠味细胞选择性地对MSG和/或IMP或GMP产生反应（如细胞内Ca（2+）浓度升高所示）。降低刺激溶液中的Ca（2+）浓度并不能显著抑制这些MSG反应，这表明所观察到的Ca（2+）释放来自细胞内储存。对小鼠菌状乳头中第二信使的测量一致地揭示了MSG使肌醇1，4，5-三磷酸和腺苷3 '，5'-环一磷酸水平增加。总之，这些结果表明，US可能会刺激两种不同的转导机制的菌状乳头。他们还表明，对于US的受体，包括代谢型和离子型谷氨酸受体的gurmarin不敏感的组分，可能通常涉及在舌头的前部和后部的味觉细胞中的鲜味的转导。
The chorda tympani (GT) and glossopharyngeal (GL) nerves of several mammalian species respond differently to umami substances (US) such as monosodium glutamate (MSG), disodium 5'-inosinate (IMP) and disodium 5'-guanylate (GMP). In mice and rhesus monkeys, responses to US are greater in the GL than the CT nerve, with the GL nerve containing larger numbers of MSG-sensitive fibers. Gurmarin, a sweet response inhibitor, suppresses the mouse CT responses to the mixture of MSG and IMP to similar to 65% of control levels but not to the metabotropic and ionotropic glutamate agonists 2-amino-4-phophonobutyrate and N-methyl-D-aspartate. Gurmarin does not inhibit any taste responses in the GL. In mice, CT responses to MSG may be masked by their greater sensitivity to sodium ions. Calcium imaging studies demonstrate that some mouse taste cells isolated from the fungiform papilla innervated by the CT respond selectively (as indicated by a rise in intracellular Ca(2+) concentrations) to MSG and/or IMP or GMP. These MSG responses are not suppressed notably by reducing the Ca(2+) concentration of the stimulus solution, suggesting that the observed Ca(2+) release is from intracellular stores. Measurements of second messengers in the mouse fungiform papilla have revealed consistently that MSG elicits increases in both inositol 1,4,5-trisphosphate and adenosine 3',5'-cyclic monophosphate levels. Together, these results suggest that US may stimulate two different transduction mechanisms in the fungiform papilla. They also suggest that gurmarin-insensitive components of receptors for US, including metabotropic and ionotropic glutamate receptors, may be commonly involved in transduction for umami taste in taste cells on both anterior and posterior parts of the tongue.