Shimada T, Hoshi T
Biochim Biophys Acta. 1987 Jul 23;901(2):265-72. doi: 10.1016/0005-2736(87)90123-4.
The steady-state intracellular pH (pHi) of isolated rabbit enterocytes was determined using 9-aminoacridine, a fluorescent weak base, and the null-point method with digitonin. When cells are incubated in a Na+-containing solution, the estimated value of pHi was in the range of 7.10-7.20, whereas it was 6.60-6.70 when cells were incubated in a Na+-free solution, indicating an important role of external Na+ in maintaining pHi at a slightly alkaline level. Pulse injection of Na+ into a Na+-free cell suspension induced a slowly developing alkalinization of pHi. The time course of the alkalinization was found to be dependent on the Na+ concentration. Li+ had the same effect as Na+, while K+ had a slight effect. Amiloride inhibited the effects of Na+ dose-dependently. These results indicate that the Na+/H+ antiport plays an important role in maintaining the pHi at a neutral or slightly alkaline level in the intact enterocytes.
利用荧光弱碱9-氨基吖啶和洋地黄皂苷零点法测定了离体兔肠上皮细胞的稳态细胞内pH值（pHi）。当细胞在含Na⁺的溶液中孵育时，pHi的估计值在7.10 - 7.20范围内，而当细胞在无Na⁺的溶液中孵育时，pHi为6.60 - 6.70，这表明细胞外Na⁺在将pHi维持在略碱性水平方面起着重要作用。向无Na⁺的细胞悬液中脉冲注入Na⁺会导致pHi缓慢发生碱化。发现碱化的时间进程取决于Na⁺浓度。Li⁺与Na⁺具有相同的作用，而K⁺的作用较小。氨氯地平剂量依赖性地抑制Na⁺的作用。这些结果表明，Na⁺/H⁺反向转运体在维持完整肠上皮细胞的pHi处于中性或略碱性水平方面起着重要作用。
