Influence of extracellular pH and perfusion rate on Na+/H+ exchange in cultured opossum kidney cells.
Influence of extracellular pH and perfusion rate on Na+/H+ exchange in cultured opossum kidney cells.
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细胞外 pH 值和灌注速率对培养负鼠肾细胞 Na /H 交换的影响。
DOI：
10.1007/bf00374984
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Murer,H
中科院分区：
文献类型：
--
作者：
Gennari,FJ;Helmle-Kolb,C;Murer,H
在培养的负鼠肾（OK）细胞中进行研究，以确定H+分泌的顶端膜Na+/H+交换的速率是否由细胞外pH值或灌注速率的变化调制。通过测量NH 4Cl负载后Na+依赖性细胞内pH恢复速率，在单细胞中评估H+分泌，使用pH敏感性荧光染料2′7′-双（羧乙基）-5，6-羧基荧光素，在单层中安装以允许顶侧和基底侧表面的独立灌注。在恒定的细胞内pH值，Na+依赖的H+分泌被发现是负相关的细胞外H+活性，并直接相关的灌注液流速。抑制H+分泌的灌流液酸度立即发生，更大的灌流液Na+减少时，与H+竞争Na+结合的转运。相比之下，灌注率的影响是一个延迟的反应，需要20分钟的曝光，是独立的灌注液Na+浓度。结果表明，细胞外pH值和灌注率调节H+分泌OK细胞，这两种效果是独立的。
Studies were undertaken in cultured opossum kidney (OK) cells to determine whether the rate of H+secretion by apical membrane Na+/H+exchange is modulated by changes in extracellular pH or perfusion rate. H+secretion was assessed in single cells by measuring the rate of Na+-dependent intracellular pH recovery after NH4Cl loading, using the pH-sensitive fluorescent dye, 2′7′-bis(carboxyethyl)-5, 6-carboxyfluorescein, in monolayers mounted to allow independent perfusion of the apical and basolateral surfaces. At constant intracellular pH, Na+-dependent H+secretion was found to be inversely related to extracellular H+activity, and directly related to the perfusate flow rate. Inhibition of H+secretion by perfusate acidity occurred immediately and was greater when perfusate Na+was reduced, consistent with H+competition with Na+for binding to the transporter. By contrast, the effect of the perfusion rate was a delayed response, requiring 20 min of exposure, and was independent of perfusate Na+concentration. The results indicate that both extracellular pH and the perfusion rate modulate H+secretion by OK cells, and that the two effects are independent.