Erdmann A, Bernhardt I, Herrmann A, Glaser R
Department of Biophysics, Faculty of Biology, Humboldt University Berlin, FRG.
Gen Physiol Biophys. 1990 Dec;9(6):577-88.
The passive Rb+ (K+) efflux from erythrocytes of seven mammalian species was investigated in solutions of physiological and low ionic strength. Furthermore the fluidity of the erythrocyte membrane in the same solutions was estimated by measuring the ESR order parameter. The rate constant of Rb+ (K+) efflux in solution of high ionic strength could be correlated with the order parameter obtained and with the mean number of double bonds to the membrane phospholipid fatty acids. The same relationships could be observed for the low ionic strength solutions if the values for human erythrocytes were excluded. The appearance of Na+, K+, Cl- cotransport to a significant extent, only in human erythrocytes, was supposed to be the reason for this different behaviour of human red blood cells. It was demonstrated that the strong increase of the Rb+ (K+) efflux rate constant for human erythrocytes in low ionic strength solution is not due to Ca2+, as quinine treatment and replacement of all external potassium, both inhibiting the Ca2(+)-induced K+ efflux, did not abolish the increase of (Rb+) K+ efflux in solutions of low ionic strength.
在生理离子强度和低离子强度的溶液中，研究了七种哺乳动物红细胞的被动铷离子（钾离子）外流情况。此外，通过测量电子自旋共振序参数，估算了相同溶液中红细胞膜的流动性。高离子强度溶液中铷离子（钾离子）外流的速率常数与所获得的序参数以及膜磷脂脂肪酸的双键平均数相关。如果排除人类红细胞的值，低离子强度溶液也存在相同的关系。仅在人类红细胞中出现显著程度的钠、钾、氯共转运，被认为是人类红细胞这种不同行为的原因。结果表明，低离子强度溶液中人类红细胞铷离子（钾离子）外流速率常数的大幅增加并非由钙离子引起，因为奎宁处理和全部外部钾离子的替代（两者均抑制钙离子诱导的钾离子外流）并未消除低离子强度溶液中（铷离子）钾离子外流的增加。
