Electrophysiological evidence for Cl secretion in shark renal proximal tubules.
Electrophysiological evidence for Cl secretion in shark renal proximal tubules.
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鲨鱼肾近曲小管 Cl 分泌的电生理证据。
DOI：
10.1152/ajprenal.1985.248.2.f282
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Fromter,E
中科院分区：
文献类型：
--
作者：
Beyenbach,KW;Fromter,E
采用常规微电极和电缆分析法研究了鲨鱼近端小管的电生理特性。在用对称林格溶液进行体外灌注的情况下，肾小管跨上皮阻力为36.3 +/- 2.3 Ω X cm 2（平均值+/- SE，n = 44）。其他电生理变量在控制条件下变化很大。在未刺激的小管（n = 16）中，跨上皮电压（VT，o）为管腔阳性（1.2 +/- 0.2 mV），基底外侧膜电位（Vbl，x）为-61.3 +/- 1.6 mV，顶端膜的电阻分数（fRa）为0.67 +/- 0.02。自发刺激的小管（n = 28）具有管腔阴性VT，o值（-1.5 +/- 0.4 mV）、低Vbi，x值（-41.3 +/- 1.7 mV）和低fRa值（0.30 +/- 0.02）。刺激状态可以通过用cAMP处理在未刺激的小管中诱导。多个微电极穿刺在一个单一的肾小管上皮细胞共享相似的电生理特性。选择性离子取代在小管腔和管周浴发现增加的Cl电导在顶端膜的自发和cAMP刺激的小管。蒽-9-羧酸倾向于逆转刺激状态，呋塞米超极化Vbl，x。这些结果构成了第一个证据分泌氯运输在肾近端小管。离子置换，刺激剂和抑制剂的电生理反应是惊人的相似，已知的Cl-转运上皮细胞。
The electrophysiology of shark proximal tubules (Squalus acanthias) was investigated using conventional microelectrodes and cable analysis. Under in vitro perfusion with symmetrical Ringer solutions, tubule transepithelial resistance was 36.3 +/- 2.3 omega X cm2 (means +/- SE, n = 44). Other electrophysiological variables varied widely under control conditions. In unstimulated tubules (n = 16) the transepithelial voltage (VT,o) was lumen positive (1.2 +/- 0.2 mV), the basolateral membrane potential (Vbl,x) was -61.3 +/- 1.6 mV, and the fractional resistance of the apical membrane (fRa) was 0.67 +/- 0.02. Spontaneously stimulated tubules (n = 28) had lumen-negative VT,o values (-1.5 +/- 0.4 mV), low Vbl,x values (-41.3 +/- 1.7 mV), and low fRa values (0.30 +/- 0.02). The stimulated state can be induced in unstimulated tubules via treatment with cAMP. Multiple microelectrode impalements in a single tubule revealed epithelial cells sharing similar electrophysiological properties. Selective ion substitutions in the tubule lumen and peritubular bath uncovered an increased Cl conductance in the apical membrane of spontaneously and cAMP-stimulated tubules. Anthracene-9-carboxylic acid tended to reverse the stimulated state, and furosemide hyperpolarized Vbl,x. These results constitute the first evidence for secretory Cl transport in a renal proximal tubule. The electrophysiological responses to ion substitutions, stimulators, and inhibitors are strikingly similar to those of known Cl-transporting epithelia.