Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon 97239-3098, USA.
J Neurochem. 2010 Dec;115(6):1530-42. doi: 10.1111/j.1471-4159.2010.07059.x. Epub 2010 Nov 19.
Epoxyeicosatrienoic acids (EETs) are bioactive eicosanoids produced from arachidonic acid by cytochrome P450 epoxygenases. We previously described the expression of cytochrome P450-2J epoxygenase in rat trigeminal ganglion neurons and that EETs signaling is involved in cerebrovascular dilation resulting from perivascular nerve stimulation. In this study, we evaluate the presence of the EETs signaling pathway in trigeminal ganglion neurons and their role in modulating the release of calcitonin gene-related peptide (CGRP) by trigeminal ganglion neurons. Liquid chromatography tandem mass spectrometry identified the presence of each of the four EETs regio-isomers within primary trigeminal ganglion neurons. Stimulation for 1 h with the transient receptor potential vanilloid-1 channel agonist capsaicin (100 nmol/L) or depolarizing K(+) (60 mmol/L) increased CGRP release as measured by ELISA. Stimulation-evoked CGRP release was attenuated by 30 min pre-treatment with the EETs antagonist 14,15-epoxyeicosa-5(Z)-enoic acid (14,15-EEZE, 10 μmol/L). K(+) stimulation elevated CGRP release 2.9 ± 0.3-fold above control levels, whereas in the presence of 14,15-EEZE K(+)-evoked CGRP release was significantly reduced to 1.1 ± 0.2-fold above control release (p < 0.01 anova, n = 6). 14,15-EEZE likewise attenuated capsaicin-evoked CGRP release from trigeminal ganglion neurons (p < 0.05 anova, n = 6). Similarly, pre-treatment with the cytochrome P450 epoxygenase inhibitor attenuated stimulation-evoked CGRP release. These data demonstrate that EETs are endogenous constituents of rat trigeminal ganglion neurons and suggest that they may act as intracellular regulators of neuropeptide release, which may have important clinical implications for treatment of migraine, stroke and vasospasm after subarachnoid hemorrhage.
环氧二十碳三烯酸（EETs）是由细胞色素 P450 加氧酶从花生四烯酸产生的生物活性类二十烷酸。我们之前描述了细胞色素 P450-2J 加氧酶在大鼠三叉神经节神经元中的表达，并且 EETs 信号参与了血管周围神经刺激引起的脑血管扩张。在这项研究中，我们评估了 EETs 信号通路在三叉神经节神经元中的存在及其在调节三叉神经节神经元中降钙素基因相关肽（CGRP）释放中的作用。液相色谱串联质谱鉴定了原代三叉神经节神经元中四种 EETs 区域异构体的存在。用辣椒素（100nmol/L）或去极化 K+（60mmol/L）刺激 1 小时可通过 ELISA 测量增加 CGRP 释放。用 EETs 拮抗剂 14,15-环氧二十碳五烯酸（14,15-EEZE，10μmol/L）预处理 30min 可减弱刺激诱导的 CGRP 释放。K+刺激使 CGRP 释放增加 2.9±0.3 倍，而在 14,15-EEZE 存在下，K+刺激引起的 CGRP 释放显著减少至对照释放的 1.1±0.2 倍（p<0.01 ANOVA，n=6）。14,15-EEZE 同样减弱了三叉神经节神经元中辣椒素诱导的 CGRP 释放（p<0.05 ANOVA，n=6）。同样，细胞色素 P450 加氧酶抑制剂的预处理减弱了刺激诱导的 CGRP 释放。这些数据表明 EETs 是大鼠三叉神经节神经元的内源性成分，表明它们可能作为神经肽释放的细胞内调节剂，这可能对偏头痛、中风和蛛网膜下腔出血后血管痉挛的治疗具有重要的临床意义。
