Solomon A K, Toon M R, Dix J A
J Membr Biol. 1986;91(3):259-73. doi: 10.1007/BF01868819.
When an osmotic pressure gradient is applied to human red cells, the volume changes anomalously, as if there were a significant fraction of "nonosmotic water" which could not serve as solvent for the cell solutes, a finding which has been discussed widely in the literature. In 1968, Gary-Bobo and Solomon (J. Gen. Physiol. 52:825) concluded that the anomalies could not be entirely explained by the colligative properties of hemoglobin (Hb) and proposed that there was an additional concentration dependence of the Hb charge (ZHb). A number of investigators, particularly Freedman and Hoffman (1979, J. Gen. Physiol. 74:157) have been unable to confirm Gary-Bobo and Solomon's experimental evidence for this concentration dependence of ZHb and we now report that we are also unable to repeat the earlier experiments. Nonetheless, there still remains a significant anomaly which amounts to 12.5 +/- 0.8% of the total isosmotic cell water (P much less than 0.0005, t test), even after taking account of the concentration dependence of the Hb osmotic coefficient and all the other known physical chemical constraints, ideal and nonideal. It is suggested that the anomalies at high Hb concentration in shrunken cells may arise from the ionic strength dependence of the Hb osmotic coefficient. In swollen red cells at low ionic strength, solute binding to membrane and intracellular proteins is increased and it is suggested that this factor may account, in part, for the anomalous behavior of these cells.
当对人体红细胞施加渗透压梯度时，其体积会出现异常变化，就好像存在很大一部分“非渗透水”，这些水不能作为细胞溶质的溶剂，这一发现已在文献中得到广泛讨论。1968年，加里 - 博博和所罗门（《普通生理学杂志》52:825）得出结论，这些异常现象不能完全用血红蛋白（Hb）的依数性来解释，并提出Hb电荷（ZHb）存在额外的浓度依赖性。许多研究人员，特别是弗里德曼和霍夫曼（1979年，《普通生理学杂志》74:157），无法证实加里 - 博博和所罗门关于ZHb这种浓度依赖性的实验证据，我们现在报告我们也无法重复早期的实验。尽管如此，即使考虑了Hb渗透系数的浓度依赖性以及所有其他已知的物理化学限制，无论是理想的还是非理想的，仍然存在一个显著的异常现象，相当于等渗细胞总水量的12.5±0.8%（P远小于0.0005，t检验）。有人认为，收缩细胞中高Hb浓度下的异常现象可能源于Hb渗透系数对离子强度的依赖性。在低离子强度下肿胀的红细胞中，溶质与膜和细胞内蛋白质的结合增加，有人认为这个因素可能部分解释了这些细胞的异常行为。
