Fluid secretion and the Na+-K+-2Cl- cotransporter in mouse exorbital lacrimal gland.
Fluid secretion and the Na+-K+-2Cl- cotransporter in mouse exorbital lacrimal gland.
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小鼠眶外泪腺中的液体分泌和 Na -K -2Cl- 协同转运蛋白。
DOI：
10.1152/ajpcell.00526.2004
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Brink,PeterR
中科院分区：
文献类型：
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作者：
Walcott,Benjamin;Birzgalis,Aija;Moore,LeonC;Brink,PeterR
我们以前曾提出，小鼠眼眶外泪腺的液体流动是由顶端Cl、−和K+通道的开放所驱动的。这些离子进入腺体的管腔，接着是水的渗透。在许多组织中，Na+-K+-2Cl−共转运体(NKCC1)取代了进入管腔的Cl-−和K+离子。我们推测，小鼠的眼眶外泪腺可能有NKCC1辅助转运体，它们在该腺体的液体运输中起着重要作用。我们用免疫细胞化学方法对NKCC1样免疫反应定位于腺泡细胞膜和导管细胞的基底外侧膜。我们开发了一种原位测量小鼠腺组织泪液流量及其成分的方法。用乙酰胆碱激动剂卡巴胆碱刺激产生一个峰值，然后是一个平台期。对该刺激液的离子浓度测量表明，该刺激液在K+和Cl-−中含量较高。用NKCC1共转运体的阻断剂速尿治疗腺体，使液体流动的平台期减少了∼30%。暴露于高渗休克的分离细胞收缩20%的∼，然后显示调节性体积增加(RVI)。速尿治疗后，RVI和肿胀均被阻断。从这些腺体中分离出的细胞在氨基甲胆碱存在下会收缩10%的∼。用速尿封闭NKCC1可使∼缩小量减少50%。这些数据表明，NKCC1在小鼠眼眶外腺的液体分泌中起着重要作用。
We have previously suggested that fluid flow in the mouse exorbital lacrimal gland is driven by the opening of apical Cl−and K+channels. These ions move into the lumen of the gland and water follows by osmosis. In many tissues, the Na+-K+-2Cl−cotransporter (NKCC1) replaces the Cl−and K+ions that move into the lumen. We hypothesize that mouse exorbital lacrimal glands would have NKCC1 cotransporters and that they would be important in fluid transport by this gland. We used immunocytochemistry to localize NKCC1-like immunoreactivity to the membranes of the acinar cells as well as to the basolateral membranes of the duct cells. We developed a method to measure tear flow and its composition from mouse glands in situ. Stimulation with the acetylcholine agonist carbachol produced a peak flow followed by a plateau. Ion concentration measurements of this stimulated fluid showed it was high in K+and Cl−. Treatment of the gland with furosemide, a blocker of the NKCC1 cotransporter, reduced the plateau phase of fluid flow by ∼30%. Isolated cells exposed to a hypertonic shock shrank by ∼20% and then showed a regulatory volume increase (RVI). Both the RVI and swelling were blocked by treatment with furosemide. Cells isolated from these glands shrink by ∼10% in the presence of carbachol. Blocking NKCC1 with furosemide reduced the amount of shrinkage by ∼50%. These data suggest that NKCC1 plays an important role in fluid secretion by the exorbital gland of mice.