Wright J, Maridonneau-Parini I, Cragoe E J, Schwartz J H, Tauber A I
William B. Castle Hematology Research Laboratory, Boston City Hospital, MA 02118.
J Leukoc Biol. 1988 Feb;43(2):183-6. doi: 10.1002/jlb.43.2.183.
The Na+/H+ antiporter has been shown to regulate activation of the human neutrophil. To delineate the role of the antiporter in the stimulation cascade, superoxide [O2-) generation was observed in PMA-stimulated neutrophils in which intracellular pH (pHi) was artificially manipulated by the use of nigericin, a K+/H+ ionophore, with and without use of the Na+/H+ antiporter inhibitor, dimethylamiloride (DA). Decreased O2- generation was observed in a Na+-free, 140 mM K+ buffer, but addition of nigericin restored this parameter of neutrophil activation to levels found in physiologic Na+ media. Further, the inhibitory effects of DA on O2- generation by cells incubated in a 10 mM Na+, 130 mM K+ buffer were totally reversed by a similar concentration of nigericin. O2- generated by a membrane preparation of the NADPH-oxidase, made from cells incubated under the same experimental conditions, paralleled whole cell studies, but the activity of the oxidase did not vary when suspended in the various reaction mixtures. These experiments support the role of the Na+/H+ antiporter in neutrophil activation as a metabolic regulator of pHi that influences receptor-coupled reactions proximal to expression of the NADPH-oxidase itself.
钠氢交换体已被证明可调节人类中性粒细胞的激活。为了阐明该交换体在刺激级联反应中的作用，在经佛波酯（PMA）刺激的中性粒细胞中观察超氧化物（O₂⁻）的生成情况，其中细胞内pH（pHi）通过使用尼日利亚菌素（一种钾氢离子载体）进行人工调控，同时使用或不使用钠氢交换体抑制剂二甲基amiloride（DA）。在无钠的140 mM钾缓冲液中观察到O₂⁻生成减少，但添加尼日利亚菌素可将中性粒细胞激活的这一参数恢复到生理钠介质中的水平。此外，在10 mM钠、130 mM钾缓冲液中孵育的细胞，DA对O₂⁻生成的抑制作用可被相似浓度的尼日利亚菌素完全逆转。由在相同实验条件下孵育的细胞制备的NADPH氧化酶膜制剂产生的O₂⁻与全细胞研究结果相似，但当悬浮于各种反应混合物中时，氧化酶的活性并未改变。这些实验支持钠氢交换体在中性粒细胞激活中作为pHi的代谢调节因子的作用，其影响NADPH氧化酶本身表达近端的受体偶联反应。
