Carrier-mediated transport of tetraethylammonium across rabbit renal basolateral membrane.
Carrier-mediated transport of tetraethylammonium across rabbit renal basolateral membrane.
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载体介导的四乙铵跨兔肾基底外侧膜的转运。
DOI：
10.1152/ajprenal.1989.257.2.f243
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
F. Roch
中科院分区：
文献类型：
--
作者：
C. Montrose‐Rafizadeh;F. Mingard;H. Murer;F. Roch
研究了四乙基铵(TEA)在兔肾皮质基底膜(BLM)囊泡中的转运机制。用10 mM TEA或1 mM甲哌利多预充注囊泡可刺激15-S对[14C]-TEA的摄取，而对照组囊泡摄取[14C]-TEA的比例分别为258%和200%，并产生超调量(分别为平衡值的3倍和1.6倍)。在K+梯度存在的情况下，当加入伐林霉素使小泡的膜电位变为负值时，TEA的净摄取量也增加(并且超调了2倍)。茶叶-茶叶交换和电压驱动的茶叶净转运都被其他有机阳离子顺式抑制，并且两种转运机制的亲和力顺序相似(奎宁大于阿米洛利大于吗啡大于甲哌啶大于胆碱=N1-甲基烟酰胺)。这一数据表明，相同的运输蛋白可能对这两种现象负责。其他实验确定，BLM囊泡没有TEA-H+交换，就其对茶叶运输的贡献而言，刷状边界膜对囊泡种群的污染可以忽略不计。这些结果证明了TEA在兔肾BLM中存在交换反应，从而暗示了TEA通过这些膜进行载体介导的转运。
Mechanisms of tetraethylammonium (TEA) transport were investigated in basolateral membrane (BLM) vesicles from rabbit renal cortex. Preloading vesicles with 10 mM TEA or 1 mM mepiperphenidol stimulated the 15-s uptake of [14C]-TEA compared with control vesicles (258 and 200%, respectively) and produced an overshoot of the equilibrium value (3 and 1.6 times, respectively). In the presence of a K+ gradient, net TEA uptake was also increased (and showed an overshoot of 2-fold) when the membrane potential of vesicles was made interior negative by adding valinomycin. Both TEA-TEA exchange and the voltage-driven net TEA transport were cis-inhibited by other organic cations, and a similar affinity order was found for both transport mechanisms (quinine greater than amiloride greater than morphine greater than mepiperphenidol greater than choline = N1-methylnicotinamide). This data suggests that the same transport protein might be responsible for both phenomena. Other experiments determined that the BLM vesicles had no TEA-H+ exchange, and that contamination of the vesicle population by brush-border membranes was negligible in terms of their contribution to TEA transport. These results demonstrate the presence of an exchange reaction for TEA in the rabbit renal BLM and thus imply carrier-mediated transport of TEA by these membranes.