汞抑制P2X4受体介导的ATP-激活电流  

Mercury inhibits the ATP-activated currents mediated by P2X4 receptor

作　　者：高越[1] 徐珍[2] 胡晓凤[1] 徐元媛[1] 鲍华芳[1] 张玉芹[1] 

机构地区：[1]武汉科技大学医学院生理学教研室,湖北武汉430065 [2]武汉钢铁集团公司第二职工医院内科

出　　处：《毒理学杂志》2012年第3期183-187,共5页Journal of Toxicology

基　　金：武汉科技大学医学院创新基金资助项目(10ZRP092);湖北省教育厅重点科研项目(20081108)

摘　　要：目的研究汞对P2X4嘌呤受体介导的ATP-激活电流(ATP-activated currents,IATP)的影响及其特征。方法将编码大鼠P2X4受体的cDNA在体外转录成cRNA,通过显微注射技术将该cRNA注入非洲爪蟾卵母细胞中进行表达。应用全细胞双电极电压钳技术研究汞对P2X4受体介导的IATP的影响。结果大鼠P2X4受体能有效地表达于非洲爪蟾卵母细胞;汞对P2X4受体介导的IATP具有抑制作用;汞使ATP的量-效曲线右下移,最大效应电流比单独加入ATP时减小,汞的IC50是(8.9±5.3)μmol/L;随着汞孵育时间增加,对IATP的抑制效应也相应增加,并在5 min之后出现最大抑制效应;钳制电位为-120,-100,-60,-40,-20,20(mV)的情况下,汞对IATP的抑制作用差异无统计学意义。结论汞抑制P2X4受体介导的IATP具有可逆性、浓度依赖性和时间依赖性,无电压依赖性。Objective To investigate the characteristic and effect of Mercury on ATP-activated currents（IATP） mediated by P2X4 receptor.Methods The cDNA coding for the rat P2X4 receptor was transcribed to cRNA in vitro and the cRNA was injected to oocytes of an Xenopus laevis using the Microinjection technique.The effect of Mercury on IATP mediated by P2X4 receptor was revealed by using the two-electrode whole-cell voltage clamp technique.Results The rat P2X4 receptors could be efficiently expressed in Xenopus oocytes;Mercury inhibited the ATP-activated currents mediated by P2X4 receptors and also inhibited the ATP Dose-response curve,displacing it downward.The maximum current in the presence of mercury was smaller compared to that when ATP was applied alone.Its IC50 was（8.9±5.3） μmol/L;With the mercury pre-incubation time increased,the effect of mercury inhibition on ATP-activated current was increased correspondingly,and the maximum inhibitory effect appeared 5 minutes later;When holding potential was changed from-120 mV to 20 mV,the inhibitory effect of Mercury on ATP-activated current did not show significant difference.Conclusion The inhibitory effect of Mercury on ATP-activated current was reversible,concentration-dependent,time-dependent,and non-voltage-dependent.

关 键 词：汞 ATP-激活电流 P2X4受体 爪蟾卵母细胞 双电极电压钳技术 

分 类 号：R338[医药卫生—人体生理学]