Electrochemical analysis of renal Na+-glucose cotransport in salamander proximal tubules.
Electrochemical analysis of renal Na+-glucose cotransport in salamander proximal tubules.
复制标题
蝾螈近曲小管肾钠-葡萄糖协同转运的电化学分析。
DOI：
10.1152/ajprenal.1987.252.1.f154
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
Boulpaep,EL
中科院分区：
文献类型：
--
作者：
Morgunov,N;Boulpaep,EL
在离体灌流的虎纹钝口鱼肾脏近曲小管中，研究了与D-葡萄糖吸收相关的膜电参数和细胞内钠活性的变化。向无基质的管腔灌注液中加入10 mM D-葡萄糖，基底外侧膜和管腔膜电位分别去极化-16.2 +/-0.9 mV和+20.4 +/-0.9 mV（P <0.01），细胞内钠活性（acellNa）增加5.1 +/- 0.8 mM（P <0.01）和显著（P <0.01）降低管腔膜阻力，从2，859 +/- 454降至1，483 +/- 120 Ω X cm 2。鲁米那葡萄糖诱导的产电反应和acellNa的变化都是鲁米那葡萄糖和钠浓度的饱和函数。鲁米那葡萄糖的产电反应对细胞内葡萄糖浓度敏感，而鲁米那葡萄糖引起的acellNa变化对细胞内钠浓度敏感。在膜电位和研究的生理范围内，钠-葡萄糖协同转运蛋白对有利的电梯度的降低比对跨腔膜的钠的有利的化学梯度的增加更敏感。
The changes in electrical membrane parameters and intracellular sodium activity associated with the absorption of D-glucose were studied in the isolated perfused proximal tubule of the Ambystoma tigrinum kidney. The addition of 10 mM D-glucose to a substrate-free luminal perfusate depolarized the basolateral and luminal membrane potentials by -16.2 +/- 0.9 mV and +20.4 +/- 0.9 mV, respectively (P less than 0.01), increased intracellular sodium activity (acellNa) by 5.1 +/- 0.8 mM (P less than 0.01) and significantly (P less than 0.01) decreased luminal membrane resistance from 2,859 +/- 454 to 1,483 +/- 120 omega X cm2. Both the electrogenic response and the change in acellNa induced by luminal glucose were a saturating function of luminal glucose and sodium concentrations. The electrogenic response to luminal glucose was sensitive to intracellular glucose concentration and the change in acellNa induced by luminal glucose was sensitive to intracellular sodium concentrations. Within the physiological range of membrane potentials and studied, the sodium-glucose cotransporter is more sensitive to a decrease in a favorable electrical gradient than to an increase in a favourable chemical gradient for sodium across the luminal membrane.