Vargas F F, Caviedes P F, Grant D S
Division of Cardio-Renal Drug Products, ODEI, CDER, Rockville, Maryland 20857.
Microvasc Res. 1994 Mar;47(2):153-65. doi: 10.1006/mvre.1994.1012.
Electrophysiological characteristics of cultured human umbilical vein endothelial cells (HUVEC) were determined using the patch-clamp technique in the whole cell configuration. In isolated cells, membrane potential, capacitance, and input resistance were (Mean +/- SD) - 16.3 +/- 12.7 mV, 53.9 +/- 26 pF, and 2.3 +/- 1.3 G omega, respectively (N = 26); and in confluent cells - 23.6 +/- 5.5 mV, 127 +/- 59 pF, and 0.254 +/- 0.077 G omega, respectively (N = 6). The almost 10 times higher input resistance, and smaller capacitance of isolated versus confluent cells, indicated that the latter were in electrical communication, presumably through open gap junctions, which was confirmed by intercellular diffusion of Lucifer Yellow. Whole-cell currents of isolated cells were made up of at least three components: First, two outward currents, an early transient one with activation-inactivation kinetics and a small delayed sustained component with 6.75 +/- 4.8 and 0.73 +/- 0.089 nS conductance, respectively. Second, an inward component which was rectified and had 1.58 +/-1.2 nS conductance. In contrast to a reported lack of voltage-gated channels in HUVEC, the above currents were voltage dependent. Inhibition of the whole-cell currents by external Ba2, internal Cs, and other K+ blockers indicates that the three observed currents are carried by K+. This was confirmed by changes of outside K+ concentrations shifting the I-V curve intercept in the direction expected for K(+)-selective channels. Voltage-gated Ca2+ currents were not apparent in the whole-cell current records. HUVEC membrane potential was as low as that of microvascular cells, while inward current rectification at normal external K+ was like that in arterial endothelial cells. This mixed phenotypic expression and multipotential behavior suggests that the electrical features of HUVEC may be primarily determined by embryonic origin and the local effect of the microenvironment rather than strictly by vessel size.
采用膜片钳技术的全细胞模式测定了培养的人脐静脉内皮细胞（HUVEC）的电生理特性。在分离的细胞中，膜电位、电容和输入电阻分别为（平均值±标准差）-16.3±12.7 mV、53.9±26 pF和2.3±1.3 GΩ（N = 26）；在汇合细胞中分别为-23.6±5.5 mV、127±59 pF和0.254±0.077 GΩ（N = 6）。分离细胞的输入电阻几乎是汇合细胞的10倍，且电容更小，这表明汇合细胞之间存在电偶联，推测是通过开放的缝隙连接实现的，荧光黄的细胞间扩散证实了这一点。分离细胞的全细胞电流至少由三个成分组成：第一，两个外向电流，一个是具有激活-失活动力学的早期瞬态电流，另一个是电导分别为6.75±4.8和0.73±0.089 nS的小延迟持续成分。第二，一个内向整流成分，电导为1.58±1.2 nS。与报道的HUVEC中缺乏电压门控通道相反，上述电流是电压依赖性的。外部Ba2+、内部Cs+和其他K+阻滞剂对全细胞电流的抑制表明，观察到的三种电流是由K+携带的。外部K+浓度的变化使I-V曲线截距向K+选择性通道预期的方向移动，证实了这一点。在全细胞电流记录中未观察到明显的电压门控Ca2+电流。HUVEC的膜电位与微血管细胞的膜电位一样低，而在正常外部K+条件下的内向电流整流与动脉内皮细胞的情况相似。这种混合的表型表达和多潜能行为表明，HUVEC的电特性可能主要由胚胎起源和微环境的局部作用决定，而不是严格由血管大小决定。
