Evidence for conductive Cl- pathways across the cell membranes of the thin ascending limb of Henle's loop.
Evidence for conductive Cl- pathways across the cell membranes of the thin ascending limb of Henle's loop.
复制标题
有证据表明 Cl- 传导通路穿过亨利袢薄升肢的细胞膜。
DOI：
10.1172/jci113691
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
M. Imai
中科院分区：
文献类型：
--
作者：
K. Yoshitomi;Y. Kondo;M. Imai
为研究汉勒袢（TAL）升支中Cl-是否通过跨细胞途径转运，采用常规微电极技术对离体仓鼠TAL段进行了体外灌注。平均基底外侧膜电压（VB）为-24.5 +/- 1.5 mV（n = 18）。哇巴因（10（-4）M）对VB无影响。基底外侧Cl-浓度从165 mmol/L突然降低至5 mmol/L引起大的去极化尖峰（+49.1 +/- 2.7 mV，n = 18），而跨上皮电位（VT）显示管腔正偏转33.4 +/- 1.2 mV，这表明基底外侧膜中存在大的Cl-电导。腔Cl-浓度的降低导致腔细胞膜从+24.5 +/- 2.1 mV持续去极化至-9.7 +/- 3.4 mV（n = 6），这表明在腔膜中也存在Cl-电导。由于我们以前已经表明，酸化的环境溶液抑制透壁氯渗透性，我们测试是否酸性pH值也抑制氯电导的基底外侧膜。当pH值降低到5.8时，VB的去极化峰和VT的变化时，突然减少基底侧Cl-几乎完全取消。从这些结果中，我们得出结论：（a）仓鼠TAL节段的腔和基底外侧膜都具有Cl-传导，和（B）当存在跨上皮Cl-梯度时，TAL中的Cl-转运至少部分通过跨细胞途径发生。
To examine whether Cl- is transported via transcellular pathways in the thin ascending limb of Henle's loop (TAL), conventional microelectrode technique was applied in isolated TAL segments of hamsters perfused in vitro. The average basolateral membrane voltage (VB) was -24.5 +/- 1.5 mV (n = 18). Ouabain (10(-4) M) had no effect on VB. Sudden reduction of basolateral Cl- concentration from 165 to 5 mmol/liter caused a large depolarizing spike (+49.1 +/- 2.7 mV, n = 18), while the transepithelial potential (VT) showed lumen positive deflection by 33.4 +/- 1.2 mV, which indicates that a large Cl- conductance exists in the basolateral membrane. Reduction of luminal Cl- concentration caused sustained depolarization of luminal cell membrane from +24.5 +/- 2.1 to -9.7 +/- 3.4 mV (n = 6), which indicates that there is also a Cl- conductance in the luminal membrane. Since we have previously shown that acidification of ambient solution suppresses the transmural Cl- permeability, we tested whether acid pH also inhibits the Cl- conductance of the basolateral membrane. When pH of the bathing fluid was lowered to 5.8, the depolarizing spike of VB and the change of VT upon sudden reduction of basolateral Cl- were almost completely abolished. From these results we conclude: (a) both the luminal and the basolateral membrane of hamster TAL segments have Cl- conductances, and (b) Cl- transport in the TAL takes place, at least in part, via a transcellular route when a transepithelial Cl- gradient is present.
影响因子：
19.6
作者：
KASHGARIAN, M;BIEMESDERFER, D;FORBUSH, B
通讯作者：
FORBUSH, B