Sodium transport and intracellular sodium activity in cultured human nasal epithelium.
Sodium transport and intracellular sodium activity in cultured human nasal epithelium.
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培养的人鼻上皮中的钠转运和细胞内钠活性。
DOI：
10.1152/ajpcell.1991.261.2.c319
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
Boucher,RC
中科院分区：
文献类型：
--
作者：
Willumsen,NJ;Boucher,RC
人气道上皮细胞主要是Na（+）吸收上皮细胞。为探讨Na+跨气道上皮吸收的机制，采用双管Na（+）选择性微电极研究了培养的人鼻上皮细胞（HNE）Na+跨膜转运的驱动力和途径。在对照条件下，细胞内Na+活性（acNa）为23 +/- 1 mM（n = 44份制备物，393次穿刺）。阿米洛利（10（-4）M）使顶膜超极化，并增加顶膜阻力分数，但不影响acNa。暴露于不含Na（+）的管腔溶液诱导的生物电反应与阿米洛利相似，但也使acNa降低至8 +/- 1 mM。在阿米洛利存在下，管腔Na+浓度（[Na+]）的降低也使acNa降低，而生物电参数没有进一步变化。seradine [Na+]的减少降低了aNac，这一反应被布美他尼（10（-4）M）阻断。哇巴因（10（-4）M，丝氨酸）导致等效短路电流（Ieq）降低和acNa增加。我们的结论是：1）acNa在HNE中高于大多数哺乳动物上皮细胞，2）顶膜表达传导性Na+通路，3）基底外侧膜通过Na（+）-K（+）-腺苷三磷酸酶和Na（+）-K（+）-2Cl-共转运系统转运Na+。
Human airway epithelia are predominantly Na(+)-absorbing epithelia. To investigate the mechanisms for Na+ absorption across airway epithelia, the driving forces and paths for Na+ translocation across each membrane were examined with double-barreled Na(+)-selective microelectrodes in cultured human nasal epithelium (HNE). Under control conditions, intracellular Na+ activity (acNa) was 23 +/- 1 mM (n = 44 preparations, 393 impalements). Amiloride (10(-4) M) hyperpolarized the apical membrane and increased the fractional apical membrane resistance but did not affect acNa. Exposure to Na(+)-free luminal solution induced bioelectric responses similar to amiloride but also reduced acNa to 8 +/- 1 mM. Reduction of luminal Na+ concentration ([Na+]) in the presence of amiloride also reduced acNa without further changes in bioelectric parameters. Reduction of serosal [Na+] decreased aNac, a response blocked by bumetanide (10(-4) M). Ouabain (10(-4) M, serosal) led to a reduction in equivalent short-circuit current (Ieq) and increase in acNa. We conclude that 1) acNa is higher in HNE than in most mammalian epithelial cells, 2) the apical membrane expresses a conductive Na+ path, and 3) the basolateral membrane transports Na+ via the Na(+)-K(+)-adenosinetriphosphatase and a Na(+)-K(+)-2Cl- cotransport system.