Proton currents in human granulocytes: regulation by membrane potential and intracellular pH.
Proton currents in human granulocytes: regulation by membrane potential and intracellular pH.
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人粒细胞中的质子电流：膜电位和细胞内 pH 值的调节。
DOI：
10.1113/jphysiol.1993.sp019723
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
K. Krause
中科院分区：
文献类型：
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作者：
N. Demaurex;S. Grinstein;Marisa Jaconi;W. Schlegel;D. Lew;K. Krause
1.为了确定传导通路是否有助于粒细胞的H+流出，我们使用了全细胞膜片钳技术结合显微荧光法测定单个二甲基亚砜分化的HL-60细胞中的细胞溶质pH（pHi）。2.在电压钳模式下，细胞从静息电位（约-60 mV）到+60 mV的去极化导致pHi增加，并伴随着相当大的外向电流。3.离子替代实验和尾电流反转电位分析表明，外向电流主要由H+携带。4. H+电流的完全激活发生在去极化后1 - 2s内，失活发生在复极化后100 - 200 ms内。5.此H+电导强烈依赖于pH值，在酸性pH值较大。此外，在低pH值的电压激活的H+电导的阈值被转移到更负的值。6.此外，毫摩尔浓度的Cd 2+和Zn 2+的浴溶液中减少了最大的H+电导和移动的H+电导的电压依赖性更积极的电位。这些影响是可逆的。7.总之，我们的结果表明，粒细胞HL-60细胞具有电压门控和pHi敏感的H+电导。由于去极化和胞质酸化都发生在粒细胞的活化过程中，这种电导可能在微生物杀灭过程中粒细胞的pHi稳态中发挥作用。
1. To determine whether conductive pathways contribute to the H+ efflux from granulocytes, we used the whole‐cell patch‐clamp technique combined with microfluorimetric determinations of cytosolic pH (pHi) in single, dimethylsulphoxide‐differentiated HL‐60 cells. 2. In voltage‐clamp mode, depolarization of the cell from the resting potential (around ‐60 mV) to +60 mV caused an increase in pHi that was accompanied by a sizeable outward current. 3. Ion substitution experiments and analysis of the reversal potential of tail currents indicated that the outward current is carried largely by H+ ions. 4. Full activation of the H+ current occurred within 1‐2s after depolarization and deactivation within 100‐200 ms upon repolarization. 5. This H+ conductance was strongly dependent on pHi, being larger at acidic pH. In addition, at low pHi the threshold for voltage activation of the H+ conductance was shifted to more negative values. 6. Addition of millimolar concentrations of Cd2+ and Zn2+ to the bath solution reduced the maximum H+ conductance and shifted the voltage dependence of the H+ conductance to more positive potentials. The effects were reversible. 7. In conclusion, our results demonstrate that granulocytic HL‐60 cells possess a voltage‐gated and pHi‐sensitive H+ conductance. Because both a depolarization and a cytosolic acidification occur during the activation of granulocytes, this conductance may play a role in pHi homeostasis of granulocytes during microbial killing.