Ohta Toshio, Imagawa Toshiaki, Ito Shigeo
Laboratory of Pharmacology, Department of Biochemical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
Biochem Pharmacol. 2007 May 15;73(10):1646-56. doi: 10.1016/j.bcp.2007.01.029. Epub 2007 Jan 25.
Neurogenic components play a crucial role in inflammation and nociception. Mustard oil (MO) is a pungent plant extract from mustard seed, horseradish and wasabi, the main constituent of which is allylisothiocyanate. We have characterized the action of MO on transient receptor potential V1 (TRPV1), a key receptor of signal transduction pathways in the nociceptive system, using fura-2-based Ca(2+) imaging and the patch-clamp technique in a heterologous expression system and sensory neurons. In human embryonic kidney (HEK) 293 cells expressing porcine TRPV1 (pTRPV1), MO evoked increases of Ca(2+) in a concentration-dependent manner. A high concentration of MO elicited irreversible cell swelling. Capsazepine, ruthenium red and iodoresiniferatoxin dose-dependently suppressed the MO-induced Ca(2+) increase. MO elicited outward rectified currents in pTRPV1-expressing HEK 293 cells with a reversal potential similar to that of capsaicin. Ca(2+) responses to MO were completely abolished by the removal of external Ca(2+). MO simultaneously elicited an inward current and increase of Ca(2+) in the same cells, indicating that MO promoted Ca(2+) influx through TRPV1 channels. In cultured porcine dorsal root ganglion (DRG) neurons, MO elicited a Ca(2+) increase and inward current. Among DRG neurons responding to MO, 85% were also sensitive to capsaicin. The present data indicate that MO is a novel agonist of TRPV1 channels, and suggest that the action of MO in vivo may be partly mediated via TRPV1. These results provide an insight into the TRPV1-mediated effects of MO on inflammation and hyperalgesia.
神经源性成分在炎症和痛觉感受中起关键作用。芥子油（MO）是一种从芥菜种子、辣根和山葵中提取的辛辣植物提取物，其主要成分是异硫氰酸烯丙酯。我们使用基于fura-2的Ca(2+)成像和膜片钳技术，在异源表达系统和感觉神经元中，对MO作用于瞬时受体电位V1（TRPV1）（伤害性感受系统中信号转导途径的关键受体）的作用进行了表征。在表达猪TRPV1（pTRPV1）的人胚肾（HEK）293细胞中，MO以浓度依赖性方式引起Ca(2+)增加。高浓度的MO引起不可逆的细胞肿胀。辣椒素、钌红和碘树脂毒素剂量依赖性地抑制MO诱导的Ca(2+)增加。MO在表达pTRPV1的HEK 293细胞中引起外向整流电流，其反转电位与辣椒素相似。去除细胞外Ca(2+)后，对MO的Ca(2+)反应完全消失。MO在同一细胞中同时引起内向电流和Ca(2+)增加，表明MO促进Ca(2+)通过TRPV1通道内流。在培养的猪背根神经节（DRG）神经元中，MO引起Ca(2+)增加和内向电流。在对MO有反应的DRG神经元中，85%也对辣椒素敏感。目前的数据表明，MO是TRPV1通道的新型激动剂，并表明MO在体内的作用可能部分通过TRPV1介导。这些结果为MO对炎症和痛觉过敏的TRPV1介导效应提供了深入了解。
