Bernhardt I, Seidler G, Ihrig I, Erdmann A
Institut für Biophysik, Fachbereich Biologie, Humboldt-Universität zu Berlin, FRG.
Gen Physiol Biophys. 1992 Jun;11(3):287-99.
The Rb+(K+) efflux of erythrocytes from six mammalian species was investigated in solutions of physiological and low ionic strength. A species dependent increase of the Rb+(K+) efflux in low ionic strength solution could be observed. The rate constant of Rb+(K+) efflux of erythrocytes in physiological ionic strength solution correlates with the content of arachidonic acid of the membrane phospholipids. The same relation was observed in solution of low ionic strength with the exception of human erythrocytes. In addition, an age-dependent correlation of the rate constant of Rb+(K+) efflux from calf erythrocytes in low ionic strength solution with the content of arachidonic acid of the membrane phospholipids was found. The Rb+(K+) efflux of human erythrocytes, which is enhanced in low ionic strength solution, decreases with the decreasing temperature. The temperature-dependent ESR order parameter of a fatty acid spin label for human and cow erythrocytes in solution of physiological and low ionic strength media suggested that the effect of low ionic strength on Rb+(K+) efflux is not solely based on a change of membrane fluidity. The results are interpreted as being due to a specific influence of membrane phospholipids on the Rb+(K+) efflux.
在生理离子强度和低离子强度溶液中，研究了六种哺乳动物红细胞的Rb⁺（K⁺）外流。在低离子强度溶液中可观察到Rb⁺（K⁺）外流随物种的增加。生理离子强度溶液中红细胞Rb⁺（K⁺）外流的速率常数与膜磷脂中花生四烯酸的含量相关。在低离子强度溶液中也观察到了相同的关系，但人类红细胞除外。此外，还发现低离子强度溶液中小牛红细胞Rb⁺（K⁺）外流的速率常数与膜磷脂中花生四烯酸的含量存在年龄依赖性相关性。人类红细胞的Rb⁺（K⁺）外流在低离子强度溶液中增强，且随温度降低而降低。生理离子强度和低离子强度介质溶液中人类和牛红细胞脂肪酸自旋标记的温度依赖性ESR序参数表明，低离子强度对Rb⁺（K⁺）外流的影响并非仅基于膜流动性的变化。结果被解释为是由于膜磷脂对Rb⁺（K⁺）外流的特定影响。
