NaCl transport in mouse medullary thick ascending limbs. II. ADH enhancement of transcellular NaCl cotransport; origin of transepithelial voltage.
NaCl transport in mouse medullary thick ascending limbs. II. ADH enhancement of transcellular NaCl cotransport; origin of transepithelial voltage.
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小鼠髓质厚升肢中的 NaCl 转运。
DOI：
10.1152/ajprenal.1981.241.4.f432
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
Andreoli,TE
中科院分区：
文献类型：
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作者：
Hebert,SC;Culpepper,RM;Andreoli,TE
我们测量了在ADH存在或不存在的情况下，肾小管灌注率和Henle髓质粗升支（mTALH）中的净NaCl转运率之间的关系。这些数据与mTALH的已知Na+、Cl-和水渗透性特征一起用于计算Tau NaCl（mol . s-1条件下cm-2），保守的Cl-从管腔通过细胞运输到间隙的速率;和CNaCl，侧部细胞间隙中的有效NaCl浓度。实验结果表明，在这些小管中，净Cl-吸收率随灌注率单调增加，并且在给定的灌注率下，ADH增加净盐吸收率。理论计算清楚地表明，ADH介导的盐吸收的增加依赖于保守的跨细胞Cl-转运速率的增加。然而，目前的分析数据不允许之间的区别完全electroneutral顶端膜NaCl入口相对于一个过程中，顶端膜Na+/Cl-入口具有小于统一的化学计量，和生电Na+运输占净Na+吸收的其余部分。Na+/Cl-顶端膜进入步骤的化学计量的鉴定将取决于，除其他因素外，明确确定细胞旁液的扩散阻力和跨连接复合物的被动离子转运模式。
We measured the relations between tubular perfusion rate and the rate of net NaCl transport in medullary thick ascending limbs of Henle (mTALH) either in the presence or absence of ADH. These data, together with the known Na+, Cl-, and water permeability characteristics of the mTALH, were used to calculate tau NaCl (mol . s-1 . cm-2), the rate of conservative Cl- transport from lumen through cells to interspaces; and CNaCl, the effective NaCl concentration in lateral intercellular spaces. The experimental results indicate that in these tubules the rate of net Cl- absorption increases monotonically with perfusion rate, and that at a given perfusion rate ADH increases the rate of net salt absorption. The theoretical calculations show clearly that the ADH-mediated increase in salt absorption depends on an increase in the rate of conservative transcellular Cl- transport. However, the present analytical data do not permit a distinction between wholly electroneutral apical membrane NaCl entry with respect to a process in which apical membrane Na+/Cl- entry has a stoichiometry less than unity, and electrogenic Na+ transport accounts for the remaining component of net Na+ absorption. Identification of the stoichiometry of the Na+/Cl- apical membrane entry step will depend, among other factors, on identifying explicitly the diffusion resistance of paracellular fluid and the mode of passive ion transport across junctional complexes.