维生素C对不同亚型甘氨酸受体功能的影响  

Effects of vitamin C on function of different subtypes of glycine receptors

作　　者：徐延 邹桂昌 左欣 熊伟 XU Yan;ZOU Gui-chang;ZUO Xin;XIONG Wei(School of Life Science and Medicine, School of Life Science, University of Science and Technology of China,Hefei 230022,China)

机构地区：[1]中国科学技术大学生命科学与医学部、生命科学学院,安徽合肥230022

出　　处：《中国药理学通报》2021年第2期187-191,共5页Chinese Pharmacological Bulletin

基　　金：科技部国家高技术研究发展(863)计划(No 2014AA020535)。

摘　　要：目的探讨维生素C(vitamin C,VC)对甘氨酸受体(glycine receptor,GlyR)功能的影响。方法使用表达GlyR不同亚型的质粒转染HEK-293T细胞,并孵育不同浓度的VC,通过膜片钳技术记录孵育VC前后GlyR在EC2浓度的甘氨酸(glycine,Gly)作用下所介导的氯电流。检测2型钠离子依赖性维生素C转运体(sodium-dependent vitamin C transporter-type 2,SVCT2)的抑制剂磺吡酮(sulfinpyrazone,SE)对VC与GlyR关系的影响。通过氨基酸点突变探究VC作用于GlyR的可能位点。结果VC剂量依赖的增强GlyRα1和GlyRα3介导的电流,并且GlyRα3对VC的作用更加敏感。对于GlyRα2,VC并未表现出显著的增强作用。SE不影响VC对GlyR介导的电流的增强作用。GlyR第3跨膜片段的第296位丝氨酸的突变显著降低了VC对GlyR功能的增强效果。结论VC显著增强GlyRα1和GlyRα3的功能,但不影响GlyRα2的功能。VC对GlyR的作用不是通过进入细胞内起作用的。GlyR第296位的丝氨酸在VC对GlyR功能的增强作用中起关键作用。Aim To investigate the effects of vitamin C(VC)on glycine receptor(GlyR)subtypes.Methods The HEK-293T cells were transfected with plasmids expressing different subtypes of GlyR.Then the cells were incubated with different concentrations of VC.The EC2 concentration of glycine-activated currents were recorded by patch clamp before or after incubation of VC.The effects of the sodium-dependent vitamin C transporter-type 2(SVCT2)inhibitor sulfinpyrazone on VC induced potentiation of GlyRs were also examined.The method of amino acid point mutation was used to explore the critical site for interaction between VC and GlyR.Results Ascorbic acid dose-dependently increased the currents mediated by GlyRα1 and GlyRα3,withα3 subunits being the most sensitive to VC.Ascorbic acid had no significant effect on the current mediated by theα2 subunit of GlyRs.Cell incubation with sulfinpyrazone did not affect the VC induced potentiation of GlyR function.The mutation of Ser296 at the third transmembrane domain ofα3 GlyR significantly reduced the potentiation of VC on GlyR function.Conclusions Ascorbic acid can enhance the function of GlyRα1 andα3 subunits,but notα2 subunit.Such enhancement is not likely to be an effect occuring inside cells.The Ser296 of GlyR plays a key role in the VC induced enhancement of GlyR function.

关 键 词：维生素C 甘氨酸受体 离子通道 膜片钳 2型钠离子依赖性维生素C转运体 

分 类 号：R329.24[医药卫生—人体解剖和组织胚胎学] R346.4[医药卫生—基础医学]