Hamm J R, Yue G M
Am J Physiol. 1987 Jan;252(1 Pt 1):C30-7. doi: 10.1152/ajpcell.1987.252.1.C30.
The accuracy of intracellular pH (pHi) measurements by 31P nuclear magnetic resonance (NMR) spectroscopy was examined in single muscle fibers from the giant barnacle, Balanus nubilis. The pHi was derived from the chemical shifts of 2-deoxy-D-glucose-6-phosphate and inorganic phosphate. In fibers superfused with sea water at pH 7.7, pHi = 7.30 +/- 0.02 at 20 degrees C. Experimentally induced pHi changes were followed with a time resolution of 3 min. Intracellular alkalinization was induced by exposure to NH4Cl and intracellular acidification followed when NH3 was removed. Then acid extrusion was stimulated by exposure to bicarbonate containing sea water. In single muscle fibers 31P NMR results were in excellent agreement with microelectrode studies over the pH range of 6.5 to 8.0. The initial acid extrusion rate was 1.7 +/- 0.3 mmol X l-1 X min-1 at pHi 6.75. Our results showed that 31P NMR is a reliable in vivo pH probe.
利用31P核磁共振（NMR）波谱法对大型藤壶（Balanus nubilis）单根肌纤维细胞内pH值（pHi）测量的准确性进行了检测。pHi由2-脱氧-D-葡萄糖-6-磷酸和无机磷酸的化学位移推导得出。在20℃下，于pH 7.7的海水中灌流的纤维中，pHi = 7.30±0.02。以3分钟的时间分辨率跟踪实验诱导的pHi变化。通过暴露于NH4Cl诱导细胞内碱化，去除NH3后则出现细胞内酸化。然后通过暴露于含碳酸氢盐的海水刺激酸排出。在单根肌纤维中，在6.5至8.0的pH范围内，31P NMR结果与微电极研究结果高度一致。在pHi为6.75时，初始酸排出速率为1.7±0.3 mmol·l-1·min-1。我们的结果表明，31P NMR是一种可靠的体内pH探针。
