【摘要】 目的将人超极化激活的阳离子通道基因2(human hyperpolarization-activated cation channel2,hHCN2)表达于HEK293细胞系上,观察其表达的通道的电生理特点。方法利用全细胞膜片钳技术,记录转染了hHCN2的HEK293细胞上的超极化激活的阳离子流(If)。结果转染hHCN2的HEK293细胞上表达If样内向电流,在超极化时激活,随刺激电压的延长而增大,半数最大激活电压为(-109.1±0.7)mV,曲线斜率为(-12.7±0.7)mV。刺激电压变负时,激活变快。-100mV和-160mV时,激活时间常数分别为(2.5±1.1)s和(217±29)ms。此电流是细胞外钾离子浓度依赖性的,对钠离子和钾离子的相对通透性为0.67。2mmol/L的Cs+可明显抑制此电流。结论目的基因hHCN2在HEK293细胞上成功表达,表达的蛋白能形成有功能的通道,产生If样电流。更多还原

【Abstract】 Objective To investigate expression of the human HCN2 gene in HEK293 cells and the electrophysiology of the expressed channel protein. Methods The whole cell hyperpolarization-activated cAMP-gated cation channel currents of HEK293 cells transfected by hHCN2 were recorded. Results I_f-like currents could be found in HEK293 cells transfected by hHCN2. The currents were activated by hyperpolarization and increased with prolongation of stimulation duration, with half maximal activation voltage being (-109.1±0.7)mV and a slope factor of (-12.7±0.7)mV. The activation kinetics was faster with higher hyperpolarization voltage, with the activation constant being (2.5±1.1)s and (217±29)ms at -100mV and -160mV respectively. The currents increased with increase in extracellular K~+, with a relative permeation of 0.67 for sodium and potassium. Cs~+ at 2mmol/L could obviously inhibit these currents. Conclusions The target gene hHCN2 was successfully expressed in HEK293 cells. The expressed protein can form functional channels and result in I_f-like currents.更多还原