【摘要】 应用pH选择性徽电极和普通檄电极测量了蟾蜍卵母细胞内的pH值（pHi）。当用含NH₄⁺而不含HCO₃^-的溶液培灌卵母细胞时,pHi逐渐下降,在停止培灌后,pHi恢复到对照值。这个pHi恢复过程是一个H⁺的主动转运,用胆碱离子取代培灌液中的Na⁺可以抑制pHi的恢复,这种抑制作用是可逆的。伴随着细胞内pH值的恢复,细胞内Na⁺活度（Na₁⁺）呈现暂时性增加,而细胞内Cl-活度（Cl₁⁺）不变或稍有增加。实验结果提示在蟾蜍卵母细胞膜上存在着Na⁺/H⁺的交换。更多还原

【Abstract】 Using conventional and pH-sensitive microeleetrodes to measure intracellular pH (pH1) in isolated oocytes of the toad (Bufo bufo gargarizans), it was found that when oocytes were superfused with NH4+ in a nominally HCO3- -free solution, pH1 was decreased and after withdrawal of NH4+ the pH4 was returned to control value. This pH4 recovery, which indicatied an active transport, failed to occur after removal of Na+ from the superfusion fluid. Ee-addition of Na+ resulted in a full pH4 recovery. A transient rise of intracellular Na+ activity accompanied the pH4 recovery. Intracellular Cl- activity was not changed or slightly increased. These data suggest that the oocytes of toad show Na+/H+ exchange in the membrane.更多还原