Contributions of K+:Cl- cotransport and Na+/K+-ATPase to basolateral ion transport in malpighian tubules of Drosophila melanogaster.
Contributions of K+:Cl- cotransport and Na+/K+-ATPase to basolateral ion transport in malpighian tubules of Drosophila melanogaster.
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K :Cl- 共转运和 Na /K -ATP 酶对果蝇马氏管基底外侧离子转运的贡献。
DOI：
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发表时间：
1999
影响因子：
2.8
通讯作者：
Michael J. O'Donnell
中科院分区：
文献类型：
--
作者：
Stuart M. Linton;Michael J. O'Donnell
通过研究离子替代和可能的离子转运体抑制剂对果蝇液体分泌速率、基侧膜电位和分泌液阳离子组成的影响，研究了Na+和K+在果蝇马氏管基侧膜上的转运机制。[(二氢吲哚)氧基]烷酸(DIOA)和布美他尼(10(-)4moL L-1)对液体分泌的抑制表明K+：CL-共转运体是K+进入肾小管主细胞的主要途径。布美他尼对K+和Na+通量的影响与对基侧Na+：K+：2Cl-共转运体的影响不一致。根尖(>；100 mV，管腔正)和基侧(<；60 mV，细胞负向)细胞膜上的电势差异很大，这表明可以利用有利的电化学梯度使氯离子进入细胞，通过DIOA敏感的K+：CL-共转运体将K+驱动到细胞内。Na+/K+-ATPase也存在于马氏管的基侧膜上。在未受刺激的肾小管上加入10(-)5~10(-)3mol L-1哇巴因，可使基底侧电位去极化，使分泌液中Na+浓度增加50~73%，使分泌液中Na~+浓度增加10~19%，与细胞内Na~+利用率增加一致。我们认为环磷酸腺苷对顶端空泡型H+-ATPase和基底侧Na+/K+-ATPase均有激活作用。在环磷酸腺苷(CAMP)刺激的小管中，K+内流受到顶膜电位的增加和Na+/K+-ATPase的刺激。顶膜电位的增加促使K+：CL-以更快的速度共转运。哇巴因可使环磷酸腺苷刺激的肾小管液体分泌减少26%，提示Na+/K+-ATPase在K+进入肾小管上皮细胞中的作用不大。马氏管在无钾氨基酸全生理盐水(AARS)中快速分泌富Na+(15 0mmoL L-1)液体。无K+AARs的分泌可被阿米洛利和巴菲霉素A1所抑制，但不能被抑制Na+：CL-共转运的布美他尼或氢氯噻嗪所抑制。未受刺激或环磷酸腺苷刺激的肾小管基侧膜无Na+电导的证据。Na+进入肾小管细胞的可能机制包括与氨基酸和葡萄糖等有机溶质的共转运。
Mechanisms of Na+ and K+ transport across the basolateral membrane of isolated Malpighian tubules of Drosophila melanogaster were studied by examining the effects of ion substitution and putative inhibitors of specific ion transporters on fluid secretion rates, basolateral membrane potential and secreted fluid cation composition. Inhibition of fluid secretion by [(dihydroindenyl)oxy]alkanoic acid (DIOA) and bumetanide (10(-)4 mol l-1) suggested that a K+:Cl- cotransporter is the main route for K+ entry into the principal cells of the tubules. Differences in the effects of bumetanide on fluxes of K+ and Na+ are inconsistent with effects upon a basolateral Na+:K+:2Cl- cotransporter. Large differences in electrical potential across apical (>100 mV, lumen positive) and basolateral (<60 mV, cell negative) cell membranes suggest that a favourable electrochemical gradient for Cl- entry into the cell may be used to drive K+ into the cell against its electrochemical gradient, via a DIOA-sensitive K+:Cl- cotransporter. A Na+/K+-ATPase was also present in the basolateral membrane of the Malpighian tubules. Addition of 10(-)5 to 10(-)3 mol l-1 ouabain to unstimulated tubules depolarized the basolateral potential, increased the Na+ concentration of the secreted fluid by 50-73 % and increased the fluid secretion rate by 10-19 %, consistent with an increased availability of intracellular Na+. We suggest that an apical vacuolar-type H+-ATPase and a basolateral Na+/K+-ATPase are both stimulated by cyclic AMP. In cyclic-AMP-stimulated tubules, K+ entry is stimulated by the increase in the apical membrane potential, which drives K+:Cl- cotransport at a faster rate, and by the stimulation of the Na+/K+-ATPase. Fluid secretion by cyclic-AMP-stimulated tubules was reduced by 26 % in the presence of ouabain, suggesting that the Na+/K+-ATPase plays a minor role in K+ entry into the tubule cells. Malpighian tubules secreted a Na+-rich (150 mmol l-1) fluid at high rates when bathed in K+-free amino-acid-replete saline (AARS). Secretion in K+-free AARS was inhibited by amiloride and bafilomycin A1, but not by bumetanide or hydrochlorothiazide, which inhibit Na+:Cl- cotransport. There was no evidence for a Na+ conductance in the basolateral membrane of unstimulated or cyclic-AMP-stimulated tubules. Possible mechanisms of Na+ entry into the tubule cells include cotransport with organic solutes such as amino acids and glucose.
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DOI：
10.1152/ajprenal.1998.275.4.f550
发表时间：
1998-10
期刊：
American journal of physiology. Renal physiology
影响因子：
--
作者：
E. Holtzman;S Kumar;C. Faaland;F. Warner;P. Logue;S. J. Erickson;G. Ricken;J. Waldman;Shiv Kumar;P. Dunham
通讯作者：
E. Holtzman;S Kumar;C. Faaland;F. Warner;P. Logue;S. J. Erickson;G. Ricken;J. Waldman;Shiv Kumar;P. Dunham
棘角鲨直肠腺高渗富氯化钠分泌的机制和控制。
DOI：
10.1242/jeb.106.1.25
发表时间：
1983
期刊：
The Journal of experimental biology
影响因子：
--
作者：
Epstein,FH;Stoff,JS;Silva,P
通讯作者：
Silva,P
电中性阳离子-氯化物协同转运蛋白。
DOI：
10.1242/jeb.201.14.2091
发表时间：
1998
期刊：
The Journal of experimental biology
影响因子：
--
作者：
Mount,DB;Delpire,E;Gamba,G;Hall,AE;Poch,E;Hoover,RS;Hebert,SC
通讯作者：
Hebert,SC
二丁酰-cAMP 增加蚊子马氏小管的基底外侧钠电导。
DOI：
10.1152/ajpregu.1985.248.3.r339
发表时间：
1985
期刊：
The American journal of physiology
影响因子：
--
作者：
Sawyer,DB;Beyenbach,KW
通讯作者：
Beyenbach,KW