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Joint Study on Mechanisms of Umami Perception : Analyzes of the responses of taste cells to monosodium glutamate

鲜味感知机制联合研究：味觉细胞对味精反应的分析

基本信息

批准号：
08044201
负责人：
MORI Tomohiko
金额：
$ 4.16万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08044201/
关键词：
taste glutamic acid mouse imaging intracellular calcium membrane potential membrane current

项目摘要

Monosodium glutamate (MSG) elicits a unique taste called umami. Whole-cell patch-clamp recordings from taste cells isolated from mouse vallate and foliate taste buds have indicated that MSG elicits several different types of responses, suggesting that multiple pathways may be involved in umami taste. We have also used fluorescent dyes and digital imaging techniques to measure MSG-evoked changes in membrane potential and intracellular calcium in taste cells from C3H mice. In this study, similar imaging techniques were used to record the responses of vallate and foliate taste cells from B6 mice to MSG (10 mM), the metabotropic receptor agonist, L-AP4 (2-amino-4-phosphonobutyrate)(1 mM) and the ionotropic receptor agonist, NMDA (1 mM). And we examined the responses of isolated mouse taste cells to MSG or L-AP4, by using whole-cell patch-clamp technique. The results suggest that MSG perception mediates via metabotropic glutamate receptor 4(mGluR 4) that decreases a membrane conductance, an … More d/or another receptor type that increases a membrane conductance. Cells in isolated taste buds were doubly stained with the voltage-sensitive dye, di-8-ANNEPS,and the Ca^<2+>-sensitive dye, fura-2. Since mGluR4 receptors in the CNS have been shown to activated Gi, blocked K channels and depolarize the cells, we examined the effect of the K channel blocker, tetraethyl ammonium (TEA), on taste cells responses. Addition of TEA (10 mM) to the bath solution resulted in membrane depolarization in about half of the taste cells. In addition, TEA markedly reduced the number of taste cells showing increases in [Ca]i in response to MSG and L-AP4. In contrast, the number of taste cells displaying responses to NMDA was not reduced by TEA.In the absence of TEA,approximately half of the cells displayd changes in membrane potential when stimulated with L-AP4. In the presence of TEA,membrane potential changes were elicited by L-AP4. These results are consistent with previous patch-clamp data suggesting that MSG activates several different mechanisms in taste cells, including processes mediated by ionotropic and metabotropic types of receptors. Less

味精（MSG）会产生一种叫做鲜味的独特味道。从小鼠叶状和叶状味蕾中分离的味觉细胞的全细胞膜片钳记录表明，味精引发了几种不同类型的反应，表明鲜味可能涉及多种途径。我们还使用荧光染料和数字成像技术测量了肌电刺激引起的C3H小鼠味觉细胞膜电位和细胞内钙的变化。在本研究中，采用类似的成像技术记录了B6小鼠的谷状和叶状味觉细胞对味精（10 mM）、代谢受体激动剂L-AP4（2-氨基-4-磷酸丁酸酯）（1 mM）和嗜离子受体激动剂NMDA （1 mM）的反应。采用全细胞膜片钳技术检测了离体小鼠味觉细胞对味精和L-AP4的反应。结果表明，味精感知通过代谢性谷氨酸受体4（mGluR 4）介导，该受体可降低细胞膜电导，而另一种受体可增加细胞膜电导。用电压敏感染料di-8-ANNEPS和Ca^<2+>敏感染料fura-2对分离的味蕾细胞进行双重染色。由于CNS中的mGluR4受体已被证明可以激活Gi，阻断K通道并使细胞去极化，因此我们研究了K通道阻滞剂四乙基铵（TEA）对味觉细胞反应的影响。在浴液中加入TEA （10 mM）导致大约一半的味觉细胞的膜去极化。此外，TEA显著减少了味精和L-AP4作用下味觉细胞的数量，显示出[Ca]i的增加。相比之下，对NMDA有反应的味觉细胞的数量并没有因为TEA而减少。在没有TEA的情况下，大约一半的细胞在L-AP4刺激下表现出膜电位的变化。在TEA存在的情况下，L-AP4引起了膜电位的变化。这些结果与先前的膜片钳数据一致，表明味精激活了味觉细胞中的几种不同机制，包括由嗜离子性和代谢性受体介导的过程。少