Intracellular alkalization causes pain sensation through activation of TRPA1 in mice
Intracellular alkalization causes pain sensation through activation of TRPA1 in mice
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DOI：
10.1172/jci35957
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发表时间：
2008-12-01
影响因子：
15.9
通讯作者：
Tominaga, Makoto
中科院分区：
文献类型：
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作者：
Fujita, Fumitaka;Uchida, Kunitoshi;Tominaga, Makoto
脊椎动物细胞需要非常窄的pH值范围才能生存。因此，细胞具有感觉和防御机制的情况下，pH值偏离可行的范围。虽然感觉神经元对酸性pH的监测已归因于几种离子通道，包括瞬时受体电位香草酸1通道（TRPV 1）和酸敏感离子通道（ASIC），但这些细胞检测碱性pH的机制尚不清楚。在这里，使用Ca 2+成像和膜片钳记录，我们表明，碱性pH激活瞬时受体电位阳离子通道，亚家族A，成员1（TRPA 1）和激活该离子通道参与伤害。此外，细胞内碱化激活TRPA 1在全细胞水平上，和单通道开口中观察到由内而外的配置，表明碱性pH激活TRPA 1从内部。突变体的分析表明，在TRPA 1的两个N-末端半胱氨酸残基参与细胞内碱化激活。此外，足底注射氯化铵到小鼠后爪引起疼痛相关的行为，没有观察到TRPA 1缺陷小鼠。这些结果表明，碱性pH通过激活TRPA 1引起痛觉，并可能为一些机制尚不清楚的人类碱性pH相关感觉障碍提供分子解释。
Vertebrate cells require a very narrow pH range for survival. Cells accordingly possess sensory and defense mechanisms for situations where the pH deviates from the viable range. Although the monitoring of acidic pH by sensory neurons has been attributed to several ion channels, including transient receptor potential vanilloid 1 channel (TRPV1) and acid-sensing ion channels (ASICs), the mechanisms by which these cells detect alkaline pH are not well understood. Here, using Ca2+ imaging and patch-clamp recording, we showed that alkaline pH activated transient receptor potential cation channel, subfamily A, member 1 (TRPA1) and that activation of this ion channel was involved in nociception. In addition, intracellular alkalization activated TRPA1 at the whole-cell level, and single-channel openings were observed in the inside-out configuration, indicating that alkaline pH activated TRPA1 from the inside. Analyses of mutants suggested that the two N-terminal cysteine residues in TRPA1 were involved in activation by intracellular alkalization. Furthermore, intraplantar injection of ammonium chloride into the mouse hind paw caused pain-related behaviors that were not observed in TRPA1-deficient mice. These results suggest that alkaline pH causes pain sensation through activation of TRPA1 and may provide a molecular explanation for some of the human alkaline pH-related sensory disorders whose mechanisms are largely unknown.