Gedde M M, Huestis W H
Department of Chemistry, Stanford University, California 94305, USA.
Biophys J. 1997 Mar;72(3):1220-33. doi: 10.1016/S0006-3495(97)78769-1.
Altered external pH transforms human erythrocytes from discocytes to stomatocytes (low pH) or echinocytes (high pH). The process is fast and reversible at room temperature, so it seems to involve shifts in weak inter- or intramolecular bonds. This shape change has been reported to depend on changes in membrane potential, but control experiments excluding roles for other simultaneously varying cell properties (cell pH, cell water, and cell chloride concentration) were not reported. The present study examined the effect of independent variation of membrane potential on red cell shape. Red cells were equilibrated in a set of solutions with graduated chloride concentrations, producing in them a wide range of membrane potentials at normal cell pH and cell water. By using assays that were rapid and accurate, cell pH, cell water, cell chloride, and membrane potential were measured in each sample. Cells remained discoid over the entire range of membrane potentials examined (-45 to +45 mV). It was concluded that membrane potential has no independent effect on red cell shape and does not mediate the membrane curvature changes known to occur in red cells equilibrated at altered pH.
外部pH值的改变会使人类红细胞从盘状细胞转变为口形细胞（低pH值）或棘形细胞（高pH值）。该过程在室温下快速且可逆，因此似乎涉及弱分子间或分子内键的变化。据报道，这种形状变化取决于膜电位的变化，但未报道排除其他同时变化的细胞特性（细胞pH值、细胞水分和细胞氯浓度）作用的对照实验。本研究考察了膜电位独立变化对红细胞形状的影响。将红细胞在一组氯化物浓度逐渐变化的溶液中平衡，在正常细胞pH值和细胞水分条件下使其产生广泛的膜电位范围。通过使用快速且准确的检测方法，对每个样本中的细胞pH值、细胞水分、细胞氯和膜电位进行了测量。在所检测的整个膜电位范围内（-45至+45 mV），细胞均保持盘状。得出的结论是，膜电位对红细胞形状没有独立影响，并且不介导已知在pH值改变时平衡的红细胞中发生的膜曲率变化。
