Ogawa A, Ishikawa Y, Sasakawa S
Japanese Red Cross Central Blood Center, Tokyo.
Thromb Res. 1989 Sep 15;55(6):683-93. doi: 10.1016/0049-3848(89)90299-5.
The cytoplasmic pH (pHc) of human platelets was lowered to 6.8-7.2 by treatment with various doses of nigericin (K+/H+ ionophore), then these platelets were stimulated with thrombin, arachidonic acid (AA), A23187 or 12-o-tetradecanoylphorbol-13-acetate (TPA), to monitor the pHc changes using a pH-sensitive fluorescent dye, BCECF. The pHc increased with the stimulation in an amiloride-sensitive manner only when the resting-pHc was lower than a certain value (pHc 6.99 for thrombin-stimulation, 6.95 for AA, 7.04 for A23187 and 6.95 for TPA, n = 3). At a higher resting-pHc, the pHc decreased. Similar observations were found using platelets acid-loaded by Na-acetate treatment. These results suggest that stimulation-induced activation of the Na+/H+ exchanger depends on cytoplasmic H+ concentration, and it can function properly only when the resting-pHc is lower than about pHc 7.
用不同剂量的尼日利亚菌素（钾离子/氢离子载体）处理后，人血小板的细胞质pH（pHc）降至6.8 - 7.2，然后用凝血酶、花生四烯酸（AA）、A23187或12 - O - 十四烷酰佛波醇 - 13 - 乙酸酯（TPA）刺激这些血小板，使用pH敏感荧光染料BCECF监测pHc变化。仅当静息pHc低于某一值时（凝血酶刺激时pHc为6.99，AA刺激时为6.95，A23187刺激时为7.04，TPA刺激时为6.95，n = 3），pHc才会以对氨氯地平敏感的方式随刺激而升高。在较高的静息pHc时，pHc会降低。使用经乙酸钠处理而酸负荷的血小板也发现了类似的观察结果。这些结果表明，刺激诱导的钠/氢交换体激活取决于细胞质氢离子浓度，并且只有当静息pHc低于约pHc 7时它才能正常发挥作用。
