摘要
目的研究钴对P2X4受体介导的ATP-激活电流(IATP)的调制作用。方法应用双微电极电压钳技术,记录细胞外液加CoCl2对表达在爪蟾卵母细胞上的大鼠颈上神经节P2X4受体介导的IATP的调制作用。结果 0.1～30μmol/L浓度范围的钴离子对P2X4受体介导的IATP呈明显的增强效应,钴浓度越高,IATP幅值越大,0.1μmol/L、0.3μmol/L、1μmol/L、3μmol/L、10μmol/L、30μmol/L的钴离子使IATP增加的百分比分别为:12.1±4.6,30.4±5.1,49.3±6.8,70.9±7.2,104.2±16.7,145.8±20.1(P<0.01);IATP的量-效曲线在钴离子的作用下向左上移位;应用1μmol/L钴离子加ATP的混合液同时灌流细胞,可导致ATP的EC50从(15.6±1.9)μmol/L降低到(8.1±0.6)μmol/L(P<0.01);即使是高浓度的钴,仍然对IATP表现出明显的增强作用;当ATP浓度不变,钳制电位变化(-140～60mV)时,钴离子对P2X4受体介导的IATP的增强作用无明显变化。结论钴对P2X4受体介导的IATP的增强效应呈浓度依赖性而非电压依赖性。钴与通道蛋白胞外环的作用位点可能与锌和镉不同。
Objective To study the modulation of cobalt on ATP-activated currents （ IATP） mediated by P2X4 receptors. Methods When P2X4 receptors were expressed in Xenopus oocytes successfully, the modulatory effects of cobalt in extracellular fluid on P2X4 receptors of rat Superior Cervical Ganglion were studied by using the two- electrode voltage clamp. Results （ 1 ） When the concentration of Co2＋ was increased from 0. 1 ±mol/L to 30 μmol/ L,the potentiation on IATP mediated by P2X4 receptors was enhanced along with increasing of Co2＋ When the concentration of Co2＋was 0. 1 μmol/L,0. 3 μmol/L,1 1.1mol/L,3 μmol/L,10 μmol/L,30μmol/L,the incremental percentage OfIATr was 12. 1 ±4.6,30.4 ±5. 1,49.3 ±6. 8,70.9 ±7.2,104.2 ± 16.7,145.8 ±20. l（P 〈0. 01）. （2） Co2＋potentiated the IATP mediated by P2X4 receptors and made the ATP concentration-respouse curve displace leftward. 1 μmol/L Co2＋plus ATP almost halved ATP EC50,which was reduced from（15.6 ± 1.9）μmol/L to（8. 1 ± 0. 6 ） ±mol/L （P 〈 0. 01 ）. （ 3 ） The magnitude of the potentiation of cobalt still increased in high concentration. （4） When ATP concentration was same and membrane potential was shifted between-140 mV and 60 mV, the potentiation of cobalt on IATP did not significantly changed. Conclusions The potentiation on IATP mediated by P2X4 receptors which caused by cobalt can be enhanced in a concentration-dependent and not voltage-independent manner. The binding sites in extracellular loop of cobalt were possibly different from zinc and cadmium.
出处
《中华临床医师杂志（电子版）》
CAS
2013年第4期155-158,共4页
Chinese Journal of Clinicians(Electronic Edition)
基金
湖北省教育厅重点科研项目(D20081108)
