高氯酸镱对大鼠背根神经元细胞毒性及膜上钾通道的影响  

The toxicity of ytterbium perchlorate in dorsal root ganglion neurons of rats and the influence of it on membrane potassium channels

作　　者：杜正清[1,2,3] 李卓玉[2,3] 杨频[2,3] 武文杰[4] 

机构地区：[1]山西财经大学环境经济学院,太原030006 [2]化学生物学与分子工程教育部重点实验室 [3]山西大学,太原030006 [4]中北大学化工与环境学院,太原030024

出　　处：《中国科学：化学》2010年第10期1536-1544,共9页SCIENTIA SINICA Chimica

基　　金：国家自然科学基金重大项目(20637010);山西省青年学术带头人项目;山西财经校级科研团队经费资助

摘　　要：研究了高氯酸镱(Yb(ClO4)3)诱导大鼠背根神经(DRG)元凋亡、引起胞内钙离子浓度变化以及对膜上钾离子通道的影响.急性分离大鼠DRG细胞,用不同浓度的Yb(ClO4)3处理DRG细胞24和96h,采用流式细胞仪和激光共聚焦法,检测细胞的凋亡和细胞内钙离子荧光强度的变化.利用全细胞膜片钳法,记录Yb(ClO4)3对细胞膜上不同钾通道电流的影响.结果表明,10,100,1000μmol/L Yb(ClO4)3处理DRG神经元24h,细胞基本不表现凋亡;处理96h,细胞出现明显的凋亡(P<0.05～0.01),尤其是1000μmol/L Yb(ClO4)3,凋亡率达到了(55.23±3.76)%(P<0.01).经Yb(ClO4)3孵育的DRG神经元胞内的Ca2+的荧光强度显著增大;Yb(ClO4)3抑制背根神经节纤维和神经元突起的生长.Yb(ClO4)3抑制DRG神经元膜上的钾电流,胞内和胞外的Yb(ClO4)3作用钾通道的部位不同.细胞外液中的Yb(ClO4)3不同程度地阻断了瞬间外向钾电流IA,对延迟整流钾电流几乎没影响;往电极内液中加入同样浓度的Yb(ClO4)3对IA影响很小,却特异性地阻断了延迟整流钾电流IK.10μmol/L Yb(ClO4)3使IA的激活和失活过程都显著右移,延长了瞬间外向钾电流达到峰值的时间和快速失活时间常数,增加神经元的兴奋性.In this study,the effects of ytterbium perchlorate inducing apoptosis of dorsal root ganglion （DRG） neurons of rats and changes of intracellular calcium ion concentration and the influence on membrane potassium ion channels were investigated. After treatment DRG cells with different concentrations of ytterbium perchlorate for 24 and 96 h,the apoptosis and fluorescence intensity changes of intracellular calcium ions were detected with flow cytometry and confocal laser scanning. Whole-cell patch clamp technique was adopted to examine the effects of intracellular and extracellular Yb3＋ on the potassium channels in rat DRG neurons. Results demonstrated that after DRG neurons were treated with 10,100,1000 μmol/L Yb （ClO4）3 for 24 h,there were generally no cell apoptosis; after 96 h treatment,there were apparent cell apoptosis （P 0.05–0.01）,especially with 1000 μmol/L Yb（ClO4）3,the apoptosis rate achieveed （55.23 ± 3.76） % （P 0.01）. The fluorescence intensity of intracellular [Ca2＋]i of DRG neurons incubated with Yb（ClO4）3 significantly increased; Yb（ClO4）3 inhibited the growth of dorsal root ganglion fibers and neurites. Yb（ClO4）3 inhibited potassium current,Yb3＋ in the intracellular or extracellular solution might interact with different sites on potassium channels. Yb3＋ in the extracellular solution played a dominant role in inhibiting the transient outward potassium current,whilst playing a minor role in affecting the delayed rectifier potassium current. Yb3＋ in the intracellular solution,however,only inhibited the delayed rectifier potassium current,without affecting the transient outward potassium current. 10 μmol/L Yb3＋ caused a significant right shift of the activation and inactivation processes of transient outward potassium current. Meanwhile,Yb3＋ delayed the time reaching the peak of transient outward potassium current,increased the time constants of inactivation. and increased the excitability of neurons. Conclusion：through influence on IA and IK on

关 键 词：DRG细胞 镱离子 凋亡 钙离子浓度 钾电流 

分 类 号：R114[医药卫生—卫生毒理学]