Grinstein S, Goetz J D, Furuya W, Rothstein A, Gelfand E W
Am J Physiol. 1984 Sep;247(3 Pt 1):C293-8. doi: 10.1152/ajpcell.1984.247.3.C293.
A new method was developed to detect the activity of the Na+-H+ exchange system as changes in cell volume. The cytoplasmic pH of isolated cells in suspension was lowered by incubation in Na-propionate medium, due to permeation of the protonated acid. This resulted in activation of Na+-H+ countertransport, measurable either as a Na+-dependent alkalinization or as an increase in 22Na+ uptake, both of which are amiloride sensitive. The continued operation of the antiport on prolonged exposure to Na-propionate results in a considerable increase in Na+ (and presumably propionate-) content. This is accompanied by an osmotic water shift and cell swelling, detectable by electronic sizing. This method was used to investigate the presence of the Na+-H+ exchanger in human platelets, neutrophils, lymphocytes, and monocytes as well as in cultured cell lines of B and T lymphoblasts and of macrophages. All these cell types displayed an amiloride-sensitive swelling when suspended in Na-propionate media. The results suggest the ubiquity of the Na+-H+ exchange system in the plasma membrane of nucleated mammalian blood cells.
开发了一种新方法，以检测作为细胞体积变化的Na⁺-H⁺交换系统的活性。悬浮的分离细胞在丙酸钠培养基中孵育时，由于质子化酸的渗透，细胞质pH值降低。这导致Na⁺-H⁺逆向转运被激活，可通过Na⁺依赖性碱化或22Na⁺摄取增加来测量，这两者均对氨氯地平敏感。长时间暴露于丙酸钠时，反向转运的持续运作会导致Na⁺（可能还有丙酸盐⁻）含量大幅增加。这伴随着渗透性水转移和细胞肿胀，可通过电子测量来检测。该方法用于研究人血小板、中性粒细胞、淋巴细胞和单核细胞以及B和T淋巴母细胞及巨噬细胞的培养细胞系中Na⁺-H⁺交换体的存在。当悬浮于丙酸钠培养基中时，所有这些细胞类型均表现出对氨氯地平敏感的肿胀。结果表明，Na⁺-H⁺交换系统在有核哺乳动物血细胞的质膜中普遍存在。
