Division of Cell Signaling, Okazaki Institute for Integrative Bioscience (National Institute for Physiological Sciences), National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan.
Chem Senses. 2012 Nov;37(9):809-18. doi: 10.1093/chemse/bjs065. Epub 2012 Aug 6.
6-(Methylsulfinyl)hexyl isothiocyanate (6-MSITC) and 6-(methylthio)hexyl isothiocyanate (6-MTITC) have low pungency and are responsible for the fresh flavor of wasabi (Wasabia japonica [Miq] Matsumura). In this study, we found that these two isothiocyanates activate transient receptor potential ankyrin 1 (TRPA1), and 6-MSITC activates transient receptor potential vanilloid 1 (TRPV1), but not other transient receptor potential channels expressed in sensory neurons. Both 6-MSITC and 6-MTITCinduced intracellular Ca(2+) increases in human embryonic kidney-derived 293 cells expressing mouse TRPA1 (mTRPA1) as measured by Ca(2+) imaging. In whole-cell patch-clamp recordings, 6-MSITC and 6-MTITC dose-dependently activated both mTRPA1 (EC(50) = 147±26 µM for 6-MSITC and 30±3 µM for 6-MTITC) and human TRPA1 (hTRPA1; EC(50) = 39±4 µM for 6-MSITC and 34±3 µM for 6-MTITC). In addition, TRPA1 N-terminal cysteines, which are reported to be important for channel activation by electrophilic ligands, were involved in 6-MSITC- and 6-MTITC-evoked TRPA1 activation. These isothiocyanates also activated endogenous TRPA1 expressed in mouse dorsal root ganglion neurons and intraplantar injection of 10-30 mM 6-MSITC-evoked pain-related behaviors in mice. These results indicate the following: 1) 6-MSITC and 6-MTITC activate both mTRPA1 and hTRPA1; 2) 6-MSITC activates mTRPV1; and 3) the pharmacological functions of these isothiocyanates could be derived from TRPA1 activation.
6-(甲硫基)己基异硫氰酸酯（6-MSITC）和 6-(甲基巯基)己基异硫氰酸酯（6-MTITC）具有低刺激性，是青芥辣（Wasabia japonica [Miq] Matsumura）中新鲜风味的来源。在本研究中，我们发现这两种异硫氰酸酯激活瞬时受体电位锚蛋白 1（TRPA1），6-MSITC 激活瞬时受体电位香草酸 1（TRPV1），但不激活感觉神经元中表达的其他瞬时受体电位通道。6-MSITC 和 6-MTITC 通过钙成像测量，在表达小鼠 TRPA1（mTRPA1）的人胚肾衍生 293 细胞中诱导细胞内 Ca(2+)增加。在全细胞膜片钳记录中，6-MSITC 和 6-MTITC 剂量依赖性地激活 mTRPA1（6-MSITC 的 EC(50)为 147±26 μM，6-MTITC 的 EC(50)为 30±3 μM）和人 TRPA1（hTRPA1；6-MSITC 的 EC(50)为 39±4 μM，6-MTITC 的 EC(50)为 34±3 μM）。此外，报告称 TRPA1 氨基末端半胱氨酸对亲电配体激活通道很重要，这些半胱氨酸参与 6-MSITC 和 6-MTITC 诱导的 TRPA1 激活。这些异硫氰酸酯还激活了小鼠背根神经节神经元中表达的内源性 TRPA1，并且 10-30 mM 6-MSITC 的皮内注射可诱发小鼠痛觉相关行为。这些结果表明：1）6-MSITC 和 6-MTITC 激活 mTRPA1 和 hTRPA1；2）6-MSITC 激活 mTRPV1；3）这些异硫氰酸酯的药理学功能可能源于 TRPA1 激活。
