Gedde M M, Davis D K, Huestis W H
Department of Chemistry, Stanford University, California 94305, USA.
Biophys J. 1997 Mar;72(3):1234-46. doi: 10.1016/S0006-3495(97)78770-8.
Altered external pH transforms human erythrocytes from discocytes to stomatocytes (low pH) or echinocytes (high pH). The mechanism of this transformation is unknown. The preceding companion study (Gedde and Huestis) demonstrated that these shape changes are not mediated by changes in membrane potential, as has been reported. The aim of this study was to identify the physiological properties that mediate this shape change. Red cells were placed in a wide range of physiological states by manipulation of buffer pH, chloride concentration, and osmolality. Morphology and four potential predictor properties (cell pH, membrane potential, cell water, and cell chloride concentration) were assayed. Analysis of the data set by stratification and nonlinear multivariate modeling showed that change in neither cell water nor cell chloride altered the morphology of normal pH cells. In contrast, change in cell pH caused shape change in normal-range membrane potential and cell water cells. The results show that change in cytoplasmic pH is both necessary and sufficient for the shape changes of human erythrocytes equilibrated in altered pH environments.
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）。这种转变的机制尚不清楚。之前的相关研究（格德和休斯蒂斯）表明，正如所报道的那样，这些形状变化并非由膜电位的变化介导。本研究的目的是确定介导这种形状变化的生理特性。通过调节缓冲液pH值、氯离子浓度和渗透压，将红细胞置于多种生理状态下。对形态以及四个潜在预测特性（细胞pH值、膜电位、细胞内水分和细胞内氯离子浓度）进行了测定。通过分层和非线性多变量建模对数据集进行分析表明，细胞内水分和细胞内氯离子的变化均未改变正常pH值细胞的形态。相比之下，细胞pH值的变化在正常范围的膜电位和细胞内水分的细胞中引起了形状变化。结果表明，细胞质pH值的变化对于在改变的pH环境中达到平衡的人类红细胞的形状变化既是必要的也是充分的。
