SODIUM-CONDUCTIVE AND CHLORIDE-CONDUCTIVE PATHWAYS IN CULTURED MOUSE TRACHEAL EPITHELIUM
SODIUM-CONDUCTIVE AND CHLORIDE-CONDUCTIVE PATHWAYS IN CULTURED MOUSE TRACHEAL EPITHELIUM
复制标题
DOI：
10.1152/ajplung.1992.263.5.l519
复制
发表时间：
1992-11-01
影响因子：
--
通讯作者：
VANSCOTT, MR
中科院分区：
文献类型：
--
作者：
CLARKE, LL;BURNS, KA;VANSCOTT, MR
囊性纤维化 (CF) 肺病转基因小鼠模型的实用性可能取决于小鼠的近端气道上皮是否具有与人类气道中发现的类似的 Na+- 和 Cl- 传导通路的特征。因此，使用双管 Cl-选择性微电极研究了小鼠气管上皮 (MTE) 原代培养物的电生理学特性。从新鲜切除的小鼠气管中分离的上皮细胞在可渗透的胶原蛋白支持物上形成汇合的极化单层，并在接种后 5-6 天内产生显着的跨上皮电位差（约 -10 mV）。在基础条件下，MTE单层的等效短路电流(I(eq))为-21.1+/-2.1μA/cm2，跨上皮电阻为424+/-49Ω。厘米2。细胞内测量表明，顶端（V（a））和基底外侧（V（b））膜电位差分别为-16.9 +/- 1.5和-25.4 +/- 1.5 mV；顶膜阻力分数为0.36+/-0.03；细胞内 Cl- 活性为 56.1 +/- 2.3 mM。应用鲁米那阿米洛利 (10(-4) M) 证明了心尖 Na+ 电导的存在，这降低了 I(eq)、超极化 V(a) 并增加了心尖膜的分数电阻。通过在管腔浴中用葡萄糖酸取代 Cl- 来证明顶端 Cl- 电导的存在，这降低了细胞内 Cl- 活性并增加了顶膜的分数电阻。通过将 MTE 暴露于异丙肾上腺素（10(-4) M，管腔）来测试 Cl-电导的调节，异丙肾上腺素通过激活顶膜中的去极化电导来增加 I(eq)。还发现管腔内应用 ATP (10(-4) M) 可以增加 Cl- 分泌率。我们得出的结论是，MTE 中的离子传输与正常人气道上皮细胞一样，具有以下特征：1) 顶膜中显着的阿米洛利敏感 Na+ 电导；2) 顶膜 Cl-传导途径，可由 β-肾上腺素能激动剂调节。
The utility of a transgenic murine model of cystic fibrosis (CF) lung disease will likely depend on whether the mouse's proximal airway epithelium is characterized by Na+- and Cl--conductive pathways comparable to those found in human airways. Therefore, the electrophysiological properties of primary cultures of mouse tracheal epithelium (MTE) were investigated using double-barreled, Cl--selective microelectrodes. Epithelial cells isolated from freshly excised mouse tracheae formed confluent polarized monolayers on permeable collagen supports and developed significant transepithelial potential differences (approximately -10 mV) within 5-6 days postseeding. Under basal conditions, the MTE monolayers had an equivalent short-circuit current (I(eq)) Of -21.1 +/- 2.1 muA/cm2 and a transepithelial resistance of 424 +/- 49 OMEGA . cm2. Intracellular measurements indicated that the apical (V(a)) and basolateral (V(b)) membrane potential differences were -16.9 +/- 1.5 and -25.4 +/- 1.5 mV, respectively; apical membrane fractional resistance was 0.36 +/- 0.03; and intracellular Cl- activity was 56.1 +/- 2.3 mM. The presence of an apical Na+ conductance was demonstrated by luminal amiloride application (10(-4) M), which decreased I(eq), hyperpolarized V(a), and increased the fractional resistance of the apical membrane. The presence of an apical Cl- conductance was demonstrated by substitution of Cl- with gluconate in the luminal bath, which decreased intracellular Cl- activity and increased the fractional resistance of the apical membrane. Regulation of the Cl- conductance was tested by exposing MTE to isoproterenol (10(-4) M, luminal), which increased I(eq) by activating a depolarizing conductance in the apical membrane. Luminal application of ATP (10(-4) M) was also found to increase the rate of Cl- secretion. We conclude that ion transport in MTE, like normal human airway epithelia, is characterized by 1) a significant amiloride-sensitive Na+ conductance in the apical membrane and 2) an apical membrane Cl--conductive pathway that can be regulated by beta-adrenergic agonists.