Active urea transport independent of H+ and Na+ transport in frog skin epithelium.
Active urea transport independent of H+ and Na+ transport in frog skin epithelium.
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青蛙皮肤上皮中活性尿素转运独立于 H 和 Na 转运。
DOI：
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发表时间：
1991
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通讯作者：
J. Ehrenfeld
中科院分区：
文献类型：
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作者：
I. Lacoste;S. Dunel‐Erb;B. Harvey;P. Laurent;J. Ehrenfeld
我们研究了青蛙（Rana esculenta）皮肤中的H+分泌（JH）、Na+吸收（JNa）和尿素转运（Ju）之间的关系，以适应自来水、NaCl（100 mM）和KCl（100 mM）。此外，细胞形态学的变化，特别是在富钙细胞（MRC），如下。NaCl适应刺激活跃的Ju，减少JNa和JH，并导致MRC的顶面减少。KCl适应后，JNa和JH的增加和高度相关，与Ju的两倍增加，而众多的MRC开发infoldings在他们的顶端膜。JH和Ju之间没有相关性。将皮肤夹在+/- 50 mV的范围内或将外部pH从7.4改变为5.4（在高细胞缓冲能力下）对Ju没有影响。去极化的基底外侧膜（serenium KCl林格）没有影响Ju。通过无氧溶液和巯基试剂（Hg 2+、对氯汞苯磺酸和N-乙基马来酰亚胺）酸化细胞可逆地阻断Ju。质子转运阻断剂己烯雌酚对Ju无影响。阿米洛利和衍生物（非那米和乙基异丙基阿米洛利）的顶端除了可逆地阻止朱，而哇巴因没有影响。我们的结论是，阳离子（Na+或H+）依赖的过程是不可能存在的R。食用油皮一个主要的主动运输在两个步骤的过程中是最简单的假设，占能源依赖的朱，在NaCl适应青蛙的发展。
We investigated the relationship between H+ secretion (JH), Na+ absorption (JNa), and urea transport (Ju) in skin of frogs (Rana esculenta) adapted to running tap water, NaCl (100 mM), and KCl (100 mM). In addition, cell morphological changes, particularly in the mitochondria-rich cells (MRC), were followed. NaCl adaptation stimulated an active Ju, reduced JNa and JH, and caused a decrease in the apical surface of MRC. After KCl adaptation, JNa and JH were increased and highly correlated, with a twofold increase in Ju, whereas the numerous MRC developed infoldings on their apical membranes. No correlation was found between JH and Ju. Clamping the skins in a range of +/- 50 mV or changing the external pH from 7.4 to 5.4 (at high cellular buffering power) had no effect on Ju. Depolarization of the basolateral membranes (serosal KCl-Ringer) had no effect on Ju. Ju was reversibly blocked by acidification of the cells by oxygen-free solution and sulfhydryl reagents (Hg2+, p-chloromercuribenzenesulfonic acid, and N-ethylmaleimide). Diethylstilbestrol, a proton transport blocker, had no effect on Ju. Apical addition of amiloride and derivatives (phenamil and ethylisopropyl amiloride) reversibly blocked Ju, whereas ouabain had no effect. We conclude that a cation (Na+ or H+)-dependent process is unlikely to exist in R. esculenta skin. A primary active transport in a two-step process is the simplest hypothesis to account for the energy-dependent Ju that develops in NaCl-adapted frogs.