PROPERTIES OF THE LUMEN MEMBRANE OF THE CORTICAL THICK ASCENDING LIMB OF HENLE LOOP OF RABBIT KIDNEY
PROPERTIES OF THE LUMEN MEMBRANE OF THE CORTICAL THICK ASCENDING LIMB OF HENLE LOOP OF RABBIT KIDNEY
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DOI：
10.1007/bf01063937
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发表时间：
1983-01-01
影响因子：
4.5
通讯作者：
SCHLATTER, E
中科院分区：
文献类型：
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作者：
GREGER, R;SCHLATTER, E
先前的数据表明 Na+、Cl- 和 K+ 共同转运穿过兔肾单位皮质厚升肢 (cTAL) 的管腔膜。为了使这种协同转运蛋白能够跨腔膜进行 K+ 回收，必须假设。研究了内腔膜的电导率特性。描述了刺穿体外灌注 cTAL 节段的个体细胞的方法。跨腔膜的平均 PD (PD1) 为 76 mV（腔正）。管腔灌注液 K+ 浓度的快速增加 (3.6 .fwdarw. 18.6 mmol .cntdot. 1-1) 导致 PD1 去极化 20 mV。添加到管腔灌注液中的 Ba2+ (3 mmol .cntdot. 1-1) 可抑制管腔膜的 K+ 传导通路，从而将分压器比（跨管腔膜的电流脉冲感应电压偏转除以跨基底外侧膜的电压偏转）从 2 增加到 36，并将跨上皮电阻从 34 增加到 46 Ω。厘米2。根据这些变化，并使用 VDR 和基尔霍夫定律的联立方程，可以计算出管腔膜 (88 Ω cm2)、基底外侧膜 (47 Ω cm2) 和细胞旁分流通路 (47 Ω cm2) 的电阻。使用这些单独电阻的估计值并使用 K+ 浓度阶跃实验中观察到的 PD1 变化（K+ 浓度变化为 29.+-.3 mV/十年），可以计算 K+ 的管腔膜的表观迁移数约为 0.9-1.0。这表明管腔膜本质上是 K+ 导电的。另一个系列的结果进一步强化了这一结论，其中没有获得管腔中存在 Cl 传导通路的证据。本研究的数据可用于计算一些 90-100 mmol .cntdot 的细胞内 K+ 活性。 1-1.对于这种 K+ 活性，从细胞到管腔的 K+ 扩散等于载体介导的从管腔到细胞的吸收。这表明 K+ 穿过 cTAL 段的内腔膜基本上完全回收是可行的。
Previous data suggest the cotransport of Na+, Cl- and K+ across the lumen membrane of the cortical thick ascending limb (cTAL) of rabbit nephron. For this cotransporter to operate K+ recycling across the lumen membrane has to be postulated. The conductivity properties of the lumen membrane were studied. Methods for impaling individuals cells of in vitro perfused cTAL segments are described. The mean PD across the lumen membrane (PD1) is 76 mV (lumen positive). Rapid increase in lumen perfusate K+ concentration (3.6 .fwdarw. 18.6 mmol .cntdot. 1-1) leads to a depolarization of PD1 by 20 mV. Ba2+ (3 mmol .cntdot. 1-1) added to the lumen perfusate inhibits the K+ conductive pathway of the lumen membrane, and consequently increases the voltage divider ratio (current pulse induced voltage deflection across the lumen membrane divided by that across the basolateral membrane) from 2 to 36 as well as transepithelial resistance from 34 to 46 .OMEGA. cm2. From these changes, and with the use of simultaneous equations of the VDR and of Kirchhoff''s law, the resistances of the lumen membrane (88 .OMEGA. cm2), of the basolateral membrane (47 .OMEGA. cm2), and of the paracellular shunt pathway (47 .OMEGA. cm2) can be calculated. Using these estimates of the individual resistances and using the observed change in PD1 in the K+ concentration step experiments (29 .+-. 3 mV/decade in K+ concentration change) an apparent transference number of the lumen membrane for K+ in the order of 0.9-1.0 can be calculated. This indicates that the lumen membrane is essentially K+ conductive. This conclusion is strengthened further by the results of another series in which no evidence for a Cl- conductive pathway in the lumen was obtained. The data of this study can be used to calculate the intracellular K+ activity of some 90-100 mmol .cntdot. 1-1. For this K+ activity the K+ diffusion from cell to lumen equals the carrier mediated uptake from lumen to cell. This indicates that an essentially complete recycling of K+ across the lumen membrane of the cTAL segment is feasible.