Bashford C L, Pasternak C A
J Membr Biol. 1984;79(3):275-84. doi: 10.1007/BF01871066.
The plasma membrane potential of Lettré cells has been determined with the optical indicator oxonol-V and found to be -57 mV at 37 degrees C (range -20 to -80 mV depending on the physiological condition of the cells). Increasing extracellular K+ does not depolarize cells: even in the presence of 155 mM K+ the potential is -41 mV; membrane potential is also insensitive to the chemical gradient of Na+, Mg2+, Ca2+ or Cl-. Ouabain depolarizes the cells; H+ efflux from cells is stimulated by extracellular Na+. We propose that in Lettré cells the plasma membrane potential is generated by electrogenic cation pumps. The balancing fluxes of Na+ and K+ are mainly through electroneutral cation exchanges (Na+/K+ and Na+/H+) and the magnitude of the potential is limited by organic anion leaks. Such a mechanism may operate in other biological membranes also.
已使用光学指示剂氧杂萘酚 - V测定了莱特雷细胞的质膜电位，发现在37摄氏度时为 -57 mV（根据细胞的生理状态，范围为 -20至 -80 mV）。增加细胞外钾离子浓度不会使细胞去极化：即使在存在155 mM钾离子的情况下，电位仍为 -41 mV；膜电位对钠离子、镁离子、钙离子或氯离子的化学梯度也不敏感。哇巴因会使细胞去极化；细胞外钠离子会刺激细胞内氢离子外流。我们提出，在莱特雷细胞中，质膜电位是由生电阳离子泵产生的。钠离子和钾离子的平衡通量主要通过电中性阳离子交换（钠离子/钾离子和钠离子/氢离子），电位的大小受有机阴离子泄漏的限制。这样的机制可能在其他生物膜中也起作用。
