Kinsella J L, Aronson P S
Biochim Biophys Acta. 1982 Jul 14;689(1):161-4. doi: 10.1016/0005-2736(82)90200-0.
We evaluated the H+ :Na+ coupling ratio of the Na+ -H+ exchanger present in microvillus membrane vesicles isolated from the rabbit renal cortex. Our approach was to impose transmembrane Na+ and H+ gradients of varying magnitude and then to measure the net flux of Na+ over the subsequent 5-s period. The Na+ -H+ exchanger was observed to be at equilibrium (i.e. no significant net Na+ flux) whenever [Na+]i/[Na+]0 was equal to [H+]i/[H+]0. Moreover, under all conditions the magnitude and direction of net Na+ flux was independent of changes in the transmembrane electrical potential difference. These results are consistent with a value of 1.0 for the coupling ratio of Na+ -H+ exchange in renal microvillus membrane vesicles.
我们评估了从兔肾皮质分离的微绒毛膜囊泡中存在的Na⁺-H⁺交换体的H⁺:Na⁺偶联比。我们的方法是施加不同大小的跨膜Na⁺和H⁺梯度，然后在随后的5秒内测量Na⁺的净通量。当[Na⁺]i/[Na⁺]0等于[H⁺]i/[H⁺]0时，观察到Na⁺-H⁺交换体处于平衡状态（即没有明显的净Na⁺通量）。此外，在所有条件下，净Na⁺通量的大小和方向与跨膜电位差的变化无关。这些结果与肾微绒毛膜囊泡中Na⁺-H⁺交换的偶联比为1.0的值一致。
