Vigne P, Frelin C, Lazdunski M
EMBO J. 1984 Aug;3(8):1865-70. doi: 10.1002/j.1460-2075.1984.tb02060.x.
The internal pH (pHi) of chick muscle cells is determined by the transmembrane Na+ gradient. Li+, but not K+, Rb+ or Cs+, can substitute for Na+ for regulating the internal pH of chick muscle cells. Pharmacological evidence using amiloride and amiloride analogs has shown that the Na+/H+ exchange system is the membrane mechanism that couples the pHi to the transmembrane Na+ gradient. The pHi dependence of the amiloride-sensitive Na+/H+ exchange mechanism was defined. Internal H+ interacts cooperatively with the Na+/H+ exchange system, in contrast with external H+, thus indicating an asymmetrical behaviour of this exchanger. The half-maximum effect for the activation by the internal H+ of the Na+ transporting activity of the amiloride-sensitive Na+/H+ exchange was observed at pH 7.4. The Hill coefficient of the H+ concentration dependence is higher than 3. Insulin was shown to have no effect on the pHi of chick muscle cells.
雏鸡肌肉细胞的细胞内pH值（pHi）由跨膜Na⁺梯度决定。Li⁺可替代Na⁺来调节雏鸡肌肉细胞的细胞内pH值，而K⁺、Rb⁺或Cs⁺则不能。使用氨氯吡咪及其类似物的药理学证据表明，Na⁺/H⁺交换系统是将pHi与跨膜Na⁺梯度相耦合的膜机制。确定了氨氯吡咪敏感的Na⁺/H⁺交换机制对pHi的依赖性。与细胞外H⁺相反，细胞内H⁺与Na⁺/H⁺交换系统协同相互作用，从而表明该交换器具有不对称行为。在pH 7.4时观察到细胞内H⁺对氨氯吡咪敏感的Na⁺/H⁺交换的Na⁺转运活性激活的半数最大效应。H⁺浓度依赖性的希尔系数高于3。已表明胰岛素对雏鸡肌肉细胞的pHi没有影响。
