Carrier-mediated transport systems of tetraethylammonium in rat renal brush-border and basolateral membrane vesicles.
Carrier-mediated transport systems of tetraethylammonium in rat renal brush-border and basolateral membrane vesicles.
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DOI：
10.1016/0005-2736(84)90556-x
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发表时间：
1984-06
期刊：
影响因子：
--
通讯作者：
M. Takano;K. Inui;T. Okano;H. Saito;R. Hori
中科院分区：
文献类型：
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作者：
M. Takano;K. Inui;T. Okano;H. Saito;R. Hori
[3H]四乙基铵是一种有机阳离子，研究了从大鼠肾皮质分离的刷边和基底侧膜囊中的转运。四乙基铵在刷状边界和基底外侧膜泡中具有载体介导转运的一些特征；吸收是饱和的，受反输运效应的刺激，在阿伦尼乌斯图中表现为不连续。在刷状边界膜泡中，H+梯度（[H+]i> [H+]o）的存在诱导了四乙基铵对其浓度梯度的显著刺激（超调现象），而这种浓度摄取被HgCl2完全抑制。相反，基底外侧膜泡对四乙基铵的吸收不受H+梯度的影响。valinomycin诱导的内负膜电位显著刺激了基底外侧膜泡对四乙基铵的摄取，而在刷边膜泡中没有观察到膜电位的影响。这些结果表明，四乙基铵通过电中性的H+-四乙基铵反转运系统在H+梯度的驱动下通过刷边膜转运，四乙基铵通过载流子介导的系统在基底膜上转运，这一过程受到膜内负电位的刺激。
Transport of [3H]tetraethylammonium, an organic cation, has been studied in brush-border and basolateral membrane vesicles isolated from rat kidney cortex. Some characteristics of carrier-mediated transport for tetraethylammonium were demonstrated in brush-border and basolateral membrane vesicles; the uptake was saturable, was stimulated by the countertransport effect, and showed discontinuity in an Arrhenius plot. In brush-border membrane vesicles, the presence of an H+gradient ([H+]i> [H+]o) induced a marked stimulation of tetraethylammonium uptake against its concentration gradient (overshoot phenomenon), and this concentrative uptake was completely inhibited by HgCl2. In contrast, the uptake of tetraethylammonium by basolateral membrane vesicles was unaffected by an H+gradient. Tetraethylammonium uptake by basolateral membrane vesicles was significantly stimulated by a valinomycin-induced inside-negative membrane potential, while no effect of membrane potential was observed in brush-border membrane vesicles. These results suggest that tetraethylammonium transport across brush-border membranes is driven by an H+gradient via an electroneutral H+-tetraethylammonium antiport system, and that tetraethylammonium is transported across basolateral membranes via a carrier-mediated system and this process is stimulated by an inside-negative membrane potential.