Payan P, Girard J P, Ciapa B
Dev Biol. 1983 Nov;100(1):29-38. doi: 10.1016/0012-1606(83)90197-5.
Intracellular pH (pHi) of sea urchin eggs (Paracentrotus lividus) was determined using DMO (dimethyloxazolidinedione) and a rapid filtration technique (P. Payan, J.P. Girard, R. Christen and C. Sardet (1981). Exp. Cell Res. 134, 339-344). Transfer of unfertilized or fertilized eggs from normal sea water into Na+-free artificial sea water leads to a progressive acidification and fall of intracellular Na+ content. A step rise in external Na+ to 10 meq causes a rapid but transient Na+ entry coupled to an excretion of H+, giving rise to a pHi increase. It is shown that the plasma membrane of unfertilized eggs contains a permanent and reversible Na+/H+ exchanger which contributes to the regulation of pHi. This exchange occurs with a 1:1 stoichiometry and is independent of metabolic energy. Proton excretion and sodium entry follow saturable kinetics with respect to external Na+ and are completely inhibited by amiloride. At fertilization, pHi increases from 7.38 to 7.64 and is maintained at this level by two separate mechanisms: (1) a Na+/H+ exchange with the same characteristics as in unfertilized eggs; (2) a H+-excreting system that is dependent on external Na+, amiloride sensitive, and requiring metabolic energy. The relationship between the permanent Na+/H+ exchange involved in pHi regulation and the transient Na+/H+ exchange occurring at fertilization is discussed.
利用二甲基恶唑烷二酮（DMO）和快速过滤技术（P. 帕扬、J.P. 吉拉尔、R. 克里斯滕和C. 萨代（1981年）。《实验细胞研究》134卷，339 - 344页）测定了海胆卵（地中海海胆）的细胞内pH值（pHi）。将未受精或已受精的卵从正常海水转移到无钠人工海水中会导致细胞内逐渐酸化以及细胞内钠含量下降。外部钠浓度逐步升至10毫当量会导致快速但短暂的钠内流，同时伴有氢离子排出，从而使pHi升高。结果表明，未受精卵的质膜含有一种永久性且可逆的钠/氢交换体，它有助于调节pHi。这种交换以1:1的化学计量比进行，且不依赖于代谢能量。质子排出和钠内流相对于外部钠呈现出饱和动力学，并且完全被氨氯吡脒抑制。受精时，pHi从7.38升至7.64，并通过两种独立机制维持在该水平：（1）一种与未受精卵具有相同特征的钠/氢交换；（2）一种依赖外部钠、对氨氯吡脒敏感且需要代谢能量的氢离子排出系统。文中讨论了参与pHi调节的永久性钠/氢交换与受精时发生的短暂钠/氢交换之间的关系。
