ENaC inhibition stimulates Cl- secretion in the mouse cortical collecting duct through an NKCC1-dependent mechanism
ENaC inhibition stimulates Cl- secretion in the mouse cortical collecting duct through an NKCC1-dependent mechanism
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DOI：
10.1152/ajprenal.00030.2012
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发表时间：
2012-07-01
影响因子：
4.2
通讯作者：
Wall, Susan M.
中科院分区：
文献类型：
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作者：
Pech, Vladimir;Thumova, Monika;Wall, Susan M.
Pech V、Thumova M、Kim YH、Agazatian D、Hummler E、Rossier BC、Weinstein AM、Nanami M、Wall SM。 ENaC 抑制通过 NKCC1 依赖性机制刺激小鼠皮质集合管中的 Cl- 分泌。 Am J Physiol Renal Physiol 303：F45-F55，2012 年。首次发表于 2012 年 4 月 11 日； doi:10.1152/ajprenal.00030.2012.-在体外灌注的皮质集合管 (CCD) 中，抑制上皮 Na+ 通道 (ENaC) 可减少 Cl- 吸收。由于 ENaC 不转运 Cl-，本研究的目的是确定 ENaC 如何调节 Cl- 吸收。因此，在体外灌注的CCD中测量Cl-吸收，该CCD取自给予醛固酮7天的小鼠。在野生型小鼠中，我们观察到鲁米那氢氯噻嗪对 Cl 吸收或跨上皮电压 (V-T) 没有影响。然而，在管腔液体中应用 ENaC 抑制剂 [苯扎米尔 (3 μM)] 或在浴液中应用 Na+-K+-ATPase 抑制剂可将 Cl- 吸收减少约 66-75%，并几乎消除管腔阴性 V-T。相比之下，ENaC 抑制对收集导管特异性 ENaC 缺失小鼠（Hoxb7：CRE、Scnn1a（loxlox））的 CCD 没有影响。尽管苯扎米尔敏感的 Cl- 吸收不依赖于 CFTR，但在浴液中应用 Na+-K+-2Cl(-) 协同转运抑制剂（布美他尼）或消融编码 Na+-K+-2Cl(-) 协同转运蛋白 1 (NKCC1) 的基因会减弱苯扎米尔敏感的 Cl- 吸收，尽管 V-T 的苯扎米尔敏感成分不受影响。总之，首先，在醛固酮处理小鼠的 CCD 中，大多数 Cl- 吸收对苯甲米尔敏感，而噻嗪类敏感的 Cl- 吸收是检测不到的。其次，苯扎米尔敏感的 Cl 吸收是通过抑制 ENaC 发生的，这可能是由于消除了腔阴性 V-T。最后，苯扎米尔敏感的 Cl-通量至少部分地通过依赖于 NKCC1 的途径进行跨细胞转运而发生。
Pech V, Thumova M, Kim YH, Agazatian D, Hummler E, Rossier BC, Weinstein AM, Nanami M, Wall SM. ENaC inhibition stimulates Cl- secretion in the mouse cortical collecting duct through an NKCC1-dependent mechanism. Am J Physiol Renal Physiol 303: F45-F55, 2012. First published April 11, 2012; doi:10.1152/ajprenal.00030.2012.-In cortical collecting ducts (CCDs) perfused in vitro, inhibiting the epithelial Na+ channel (ENaC) reduces Cl- absorption. Since ENaC does not transport Cl-, the purpose of this study was to determine how ENaC modulates Cl- absorption. Thus, Cl- absorption was measured in CCDs perfused in vitro that were taken from mice given aldosterone for 7 days. In wild-type mice, we observed no effect of luminal hydrochlorothiazide on either Cl- absorption or transepithelial voltage (V-T). However, application of an ENaC inhibitor [benzamil (3 mu M)] to the luminal fluid or application of a Na+-K+-ATPase inhibitor to the bath reduced Cl- absorption by similar to 66-75% and nearly obliterated lumen-negative V-T. In contrast, ENaC inhibition had no effect in CCDs from collecting duct-specific ENaC-null mice (Hoxb7: CRE, Scnn1a(loxlox)). Whereas benzamil-sensitive Cl- absorption did not depend on CFTR, application of a Na+-K+-2Cl(-) cotransport inhibitor (bumetanide) to the bath or ablation of the gene encoding Na+-K+-2Cl(-) cotransporter 1 (NKCC1) blunted benzamil-sensitive Cl- absorption, although the benzamil-sensitive component of V-T was unaffected. In conclusion, first, in CCDs from aldosterone-treated mice, most Cl- absorption is benzamil sensitive, whereas thiazide-sensitive Cl- absorption is undetectable. Second, benzamil-sensitive Cl- absorption occurs by inhibition of ENaC, possibly due to elimination of lumen-negative V-T. Finally, benzamil-sensitive Cl- flux occurs, at least in part, through transcellular transport through a pathway that depends on NKCC1.