Division of Cell Signaling, Okazaki Institute for Integrative Bioscience (National Institute for Physiological Sciences), National Institutes of Natural Sciences, Higashiyama 5-1, Myodaiji, Okazaki, Aichi, Japan.
Pflugers Arch. 2012 Apr;463(4):549-59. doi: 10.1007/s00424-011-1069-4. Epub 2012 Jan 6.
Transient receptor potential ankyrin 1 (TRPA1) is a calcium-permeable non-selective cation channel that is mainly expressed in primary nociceptive neurons. TRPA1 is activated by a variety of noxious stimuli, including cold temperatures, pungent compounds such as mustard oil and cinnamaldehyde, and intracellular alkalization. Here, we show that primary alcohols, which have been reported to cause skin, eye or nasal irritation, activate human TRPA1 (hTRPA1). We measured intracellular Ca(2+) changes in HEK293 cells expressing hTRPA1 induced by 1 mM primary alcohols. Higher alcohols (1-butanol to 1-octanol) showed Ca(2+) increases proportional to the carbon chain length. In whole-cell patch-clamp recordings, higher alcohols (1-hexanol to 1-octanol) activated hTRPA1 and the potency increased with the carbon chain length. Higher alcohols evoked single-channel opening of hTRPA1 in an inside-out configuration. In addition, cysteine at 665 in the N terminus and histidine at 983 in the C terminus were important for hTRPA1 activation by primary alcohols. Furthermore, straight-chain secondary alcohols increased intracellular Ca(2+) concentrations in HEK293 cells expressing hTRPA1, and both primary and secondary alcohols showed hTRPA1 activation activities that correlated highly with their octanol/water partition coefficients. On the other hand, mouse TRPA1 did not show a strong response to 1-hexanol or 1-octanol, nor did these alcohols evoke significant pain in mice. We conclude that primary and secondary alcohols activate hTRPA1 in a carbon chain length-dependent manner. TRPA1 could be a sensor of alcohols inducing skin, eye and nasal irritation in human.
瞬时受体电位锚蛋白 1（TRPA1）是一种钙通透性非选择性阳离子通道，主要表达于初级伤害感受神经元。TRPA1 可被多种有害刺激激活，包括低温、芥末油和肉桂醛等刺激性化合物以及细胞内碱化。在这里，我们表明，先前报道会引起皮肤、眼睛或鼻腔刺激的伯醇会激活人源 TRPA1（hTRPA1）。我们测量了表达 hTRPA1 的 HEK293 细胞中 1 mM 伯醇诱导的细胞内 Ca(2+)变化。较高的醇（1-丁醇至 1-辛醇）显示出与碳链长度成正比的 Ca(2+)增加。在全细胞膜片钳记录中，较高的醇（1-己醇至 1-辛醇）激活 hTRPA1，其效力随碳链长度增加而增加。较高的醇在内外向构型中诱导 hTRPA1 的单通道开放。此外，N 端的半胱氨酸 665 和 C 端的组氨酸 983 对于伯醇激活 hTRPA1 很重要。此外，直链仲醇增加表达 hTRPA1 的 HEK293 细胞内的 Ca(2+)浓度，并且伯醇和仲醇都表现出与它们的辛醇/水分配系数高度相关的 hTRPA1 激活活性。另一方面，小鼠 TRPA1 对 1-己醇或 1-辛醇没有强烈反应，这些醇也没有在小鼠中引起明显的疼痛。我们得出的结论是，伯醇和仲醇以碳链长度依赖性方式激活 hTRPA1。TRPA1 可能是一种感知醇类引起人类皮肤、眼睛和鼻腔刺激的传感器。
