Gokce G, Arun M Z
Department of Pharmacology, Faculty of Pharmacy, Ege University, Izmir, Turkey.
Eur Rev Med Pharmacol Sci. 2014;18(21):3339-45.
Ergothioneine (EGT) is a ubiquitous, sulphur-containing derivative of amino acid histidine, acquired by higher order plants and animals solely through dietary means. The antioxidant and cytoprotective effects of ergothioneine have been demonstrated by in vitro studies, but its physiological role remains unclear. This study aims to investigate the effects of ergothioneine (EGT) on basal and acetylcholine-stimulated activity of nitric oxide.
Effects of EGT on basal and acetylcholine (ACh)-stimulated activity of nitric oxide (NO) were tested in isolated rings of rat thoracic aorta. In parallel experiments, relaxant responses to ACh were evaluated following incubation with Cu/Zn superoxide dismutase inhibitor diethyldithiocarbamate (DETCA) and superoxide anion generating system hypoxanthine/xanthine oxidase (HX/XO). Generation of reactive oxygen species (ROS) in aortic rings was measured by means of lucigenin- and luminol-enhanced chemiluminescence, in the presence and in the absence of EGT.
EGT (1-200 µM) produced a concentration-dependent relaxation in endothelium-intact aortic rings which was abolished by endothelial denudation or NO synthase inhibition. Impaired response to ACh in DETCA and HX/XO treated rings was recovered by EGT treatment. This recovery by EGT was characterized by a significant decrease in the production of superoxide anion.
Ergothioneine, at levels normally present in blood, may protect NO from destruction by superoxide anion and play a physiologically important role in preserving NO-dependent endothelial function.
麦角硫因（EGT）是一种普遍存在的含硫氨基酸组氨酸衍生物，高等植物和动物仅通过饮食方式获取。体外研究已证实麦角硫因具有抗氧化和细胞保护作用，但其生理作用仍不清楚。本研究旨在探讨麦角硫因（EGT）对一氧化氮基础活性和乙酰胆碱刺激活性的影响。
在大鼠胸主动脉离体环中测试EGT对一氧化氮（NO）基础活性和乙酰胆碱（ACh）刺激活性的影响。在平行实验中，在用铜/锌超氧化物歧化酶抑制剂二乙基二硫代氨基甲酸盐（DETCA）和超氧阴离子生成系统次黄嘌呤/黄嘌呤氧化酶（HX/XO）孵育后，评估对ACh的舒张反应。在有和没有EGT的情况下，通过光泽精和鲁米诺增强的化学发光法测量主动脉环中活性氧（ROS）的产生。
EGT（1 - 200 μM）在内皮完整的主动脉环中产生浓度依赖性舒张，这种舒张在内皮剥脱或一氧化氮合酶抑制后被消除。EGT处理可恢复DETCA和HX/XO处理环中对ACh受损的反应。EGT的这种恢复表现为超氧阴离子产生的显著减少。
血液中正常水平的麦角硫因可能保护一氧化氮免受超氧阴离子的破坏，并在维持一氧化氮依赖性内皮功能中发挥重要生理作用。
