中文摘要：

目的研究人类三型酸敏感离子通道（hASIC3）的生理学和药理学特性。方法应用全细胞电压钳技术检测转染在COS-7细胞上的hASIC3通道的生理学和药理学特性。结果hASIC3通道能通过迅速降低胞外pH值而被激活，并在酸性环境中迅速脱敏。脱敏后的hASIC3通道恢复到50％备用状态时所需的时间为（618±21）ms。胞外pH值在（6．40±0．05）时可使50％的hASIC3通道激活。pH值低于8时hASIC3通道的利用率降低，在生理状态pH值条件下，通道利用率降低了大约50％。阿米洛利能特异性阻断快速激活快速失活hASIC3通道且半数抑制浓度为（12．5±3．0）μmol／L。hASIC3通道的电流电压（Ⅰ-Ⅴ）关系曲线在很宽广的电压范围内呈线性关系（-80～＋80mV），翻转电位为（＋43±5）mV。结论hASIC3通道作为一种酸感受器，可能对感受人体pH值的变化起很重要的作用。

英文摘要：

Objective To investigate the physiological and pharmacological characterizations of human ASIC3 （hASIC3） expressed in COS-7 cells. Methods By using cell culture, gene transfection and whole cell patch clamp technique, the characterizations of human ASIC3 （hASIC3） expressed in COS-7 cells were studied. Results hASIC3 currents were activated by changing the pH of the bathing solution and exhibited rapid desensitization upon exposure to acidic solutions; Time of 50% hASIC3 channel recovering from desensitization was （618±21） ms. Fast activated and fast inactivated hASIC3 currents were inhibited by amiloride with IC50 values of （12.5±3.0） μmol/L. In COS-7 cells the ASIC3 Ⅰ-Ⅴ relationship was linear over a wide voltage range （-80-＋80 mV） and the current reversal potential was （＋43±5） mV, Conclusion hASIC3 is an acid sensor and might play an important role in the detection of pH change in human.