Sodium and potassium fluxes and membrane potential of human neutrophils: evidence for an electrogenic sodium pump.
Sodium and potassium fluxes and membrane potential of human neutrophils: evidence for an electrogenic sodium pump.
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DOI：
10.1085/jgp.79.3.453
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发表时间：
1982-03
影响因子：
3.8
通讯作者：
De Weer, P
中科院分区：
文献类型：
--
作者：
Simchowitz, L;Spilberg, I;De Weer, P
测定离体静息人外周血多形核白细胞钠、钾离子含量及通量。37℃保存的细胞，[Na]i为25 mM， [K]i为120 mM；这两种离子与细胞外同位素完全交换。用22Na和42K测量的单向Na和K通量均约为0.9 meq/l电池水。瓦巴因对钠内流和钾外排没有影响，但抑制了95 +/- 7%的钠外排和63%的钾内流。保持在0℃的细胞以钠交换钾（[Na]i在3小时内几乎增加了两倍）；在重新加热后，瓦哈因敏感的钾流入这些细胞被强烈增强。外部K刺激Na外排（在140-mM Na介质中，Km约为1.5 mM）。PNa/PK渗透率比，估计从瓦巴因不敏感通量，是0.10。Valinomycin（1微米）大约加倍了PK。使用电位指示剂diS-C3估计膜电位（Vm） (5)；校准是基于恒定场行为的假设。外部K对Vm有影响，Cl对Vm没有影响。瓦本引起去极化，其大小取决于[Na]i。当暴露于中性交换载体莫能菌素时，钠耗尽细胞变得超极化；这种极端极化被沃巴因消除了。我们得出结论，人外周中性粒细胞的钠泵是电致的，并且泵诱导的超极化的大小与从单个K和Na电导计算的膜电导（3.7-4.0微秒/cm2）一致。
Sodium and potassium ion contents and fluxes of isolated resting human peripheral polymorphonuclear leukocytes were measured. In cells kept at 37 degrees C, [Na]i was 25 mM and [K]i was 120 mM; both ions were completely exchangeable with extracellular isotopes. One-way Na and K fluxes, measured with 22Na and 42K, were all approximately 0.9 meq/liter cell water . min. Ouabain had no effect on Na influx or K efflux, but inhibited 95 +/- 7% of Na efflux and 63% of K influx. Cells kept at 0 degree C gained sodium in exchange for potassium ([Na]i nearly tripled in 3 h); upon rewarming, ouabain-sensitive K influx into such cells was strongly enhanced. External K stimulated Na efflux (Km approximately 1.5 mM in 140-mM Na medium). The PNa/PK permeability ratio, estimated from ouabain insensitive fluxes, was 0.10. Valinomycin (1 microM) approximately doubled PK. Membrane potential (Vm) was estimated using the potentiometric indicator diS-C3(5); calibration was based on the assumption of constant-field behavior. External K, but not Cl, affected Vm. Ouabain caused a depolarization whose magnitude dependent on [Na]i. Sodium-depleted cells became hyperpolarized when exposed to the neutral exchange carrier monensin; this hyperpolarization was abolished by ouabain. We conclude that the sodium pump of human peripheral neutrophils is electrogenic, and that the size of the pump-induced hyperpolarization is consistent with the membrane conductance (3.7-4.0 microseconds/cm2) computed from the individual K and Na conductances.