表达在爪蟾卵母细胞上的大鼠P2X_4受体介导的ATP-激活电流特征  

Characteristics of ATP-activated current mediated by rat P2X_4 receptor expressed in the Xenopus oocytes

作　　者：朱凡[1] 张玉芹[1] 程华[1] 田卫华[1] 

机构地区：[1]武汉科技大学医学院生理学教研室,武汉430065

出　　处：《神经解剖学杂志》2008年第4期391-395,共5页Chinese Journal of Neuroanatomy

基　　金：湖北省自然科学基金(No.2004ABA152);湖北省教育厅科研(2006)资助项目

摘　　要：本研究应用显微注射和双电极电压钳技术对P2X4受体介导的三磷酸腺苷(ATP)-激活电流(IATP)的特征进行了研究。结果显示:(1)大鼠P2X4受体可高效表达于非洲爪蟾卵母细胞;(2)外加1μmol/L、10μmol/L和100μmol/LATP,IATP激活相的时间常数τon分别是3.58s±0.20s、2.30s±0.21s和1.3s±0.14s。IATP快失敏相的时间常数τdes分别是11.74s±0.11s、7.52s±0.24s和4.11s±0.18s。IATP慢失敏相的时间常数τoff分别为14.25s±2.30s、25.42s±4.45s和35.71s±5.92s;(3)ATP作用的量-效关系:EC50为(16.03±1.81)μmol/L,Hill系数为1.02±0.09;(4)100μmol/L的PPADS和suramin不改变IATP的幅值;(5)IATP呈电压依赖性和内向整流特性;(6)加药时间分别为20s、30s、45s和60s的情况下,IATP幅值并无显著性差异。以上结果说明了P2X4受体介导的ATP-激活电流的特征,为进一步研究P2X4受体的功能和调控机制奠定了基础。In the present study, we used microinjection and two-electrode whole-cell voltage clamp to explore the characteristics of ATP-activated current （IATP） mediated by rat P2X4 receptor expressed in Xenopus oocytes. Our results showed that： （1） The rat P2X4 receptor could be efficiently expressed in Xenopus oocytes. （2） The activation phase time constant （Ton） of IATP were 3.58 s±0.20s, 2.30s±0.21s and 1.3s±0.14s, respectively;fast desensitizing phase time constant （Tdes） of/ATP were 11.74s±0.11s, 7.52s±0.24s and 4.11s ±0.18s, respectively, while slow desensitizing phase time constant （Toff） of/ATP were 14.25s±2.30s, 25.42s±4.45s and 35.71s±5.92s, respectively; when 1 μmol/L, 10 μmol/L, and 100 μmol/L ATP are applied correspondingly. （3） The concentrationresponse relationship in ATP was measured as： （16.03± 1.81）μmol/L of EC50 to 1.02±0.09 of Hill coefficient. （4） PPADS and suramin at a concentration of 100 μmol/L had no effect on IATP mediated by rat P2X4 receptor. （5） IATP exhibits characteristics of both voltage-dependency and inward-rectification, and （6） ]ATP did not have a significant variation when applying ATP times are 20s, 30s, 45s, and 60s. The results in this study advance our understanding in the characteristics of IATP, and prepare for further investigation in the functions of P2X4 receptor and its inner modulating mechanism.

关 键 词：P2X4受体 离子通道 双电极膜片钳 爪蟾卵母细胞 

分 类 号：R33[医药卫生—人体生理学]