哇巴因对钠钾泵的抑制作用：体外不同类型人白细胞中半数有效剂量（ED50）的测定

Ouabain inhibition of the sodium-potassium pump: estimation of ED50 in different types of human leucocytes in vitro.

Møller B, Vaag A, Johansen T

Department of Pharmacology, Odense University, Denmark.

Br J Clin Pharmacol. 1990 Jan;29(1):93-100. doi: 10.1111/j.1365-2125.1990.tb03607.x.

Abstract

We examined the effect of ouabain on the Na(+)-K+ pump of intact mononuclear leucocytes and polymorphonuclear leucocytes by using the radioactive potassium analogue, 86rubidium, as a tracer and measuring the cellular uptake of K+ (86Rb+). Na(+)-K+ pump activity was determined as the cellular uptake of K+ (86Rb+) that is sensitive to ouabain, 10(-5) mol l-1. 2. Dose-response curves for inhibition of the Na(+)-K+ pump were obtained after exposure of the cells to various concentrations of ouabain for 2.5 h when the level of pump inhibition was considered to be at steady state. 3. The ED50 of ouabain for the effect on the Na(+)-K+ pump was estimated to be 3 X 10(-9) mol l-1 in the absence of potassium. In the presence of potassium, 3 and 6.5 X 10(-3) mol l-1, it was increased by factors of 10 and 45 respectively. In the presence of potassium, 4 X 10(-3) mol l-1, the ED50 was similar but somewhat higher when determined in an artificial medium (Ringer solution) than when determined in autologous plasma. 4. The ED50 values observed in the present study were very similar to KD values reported in the literature on ligand binding of tritiated ouabain to the same types of human leucocytes.

摘要

我们通过使用放射性钾类似物86铷作为示踪剂并测量细胞对K⁺（86Rb⁺）的摄取，研究了哇巴因对完整单核白细胞和多形核白细胞的Na⁺-K⁺泵的影响。Na⁺-K⁺泵活性被确定为对10⁻⁵mol l⁻¹哇巴因敏感的细胞对K⁺（86Rb⁺）的摄取。2. 当认为泵抑制水平处于稳态时，将细胞暴露于不同浓度的哇巴因2.5小时后，获得了抑制Na⁺-K⁺泵的剂量反应曲线。3. 在无钾的情况下，哇巴因对Na⁺-K⁺泵作用的半数有效剂量（ED50）估计为3×10⁻⁹mol l⁻¹。在存在3和6.5×10⁻³mol l⁻¹钾的情况下，它分别增加了10倍和45倍。在存在4×10⁻³mol l⁻¹钾的情况下，当在人工培养基（林格溶液）中测定时，ED50相似但略高于在自体血浆中测定时的值。4. 本研究中观察到的ED50值与文献中报道的关于氚化哇巴因与相同类型人类白细胞的配体结合的解离常数（KD）值非常相似。