Suppr超能文献

培养的兔肾内髓集合管细胞碳酸氢盐转运机制

Mechanisms of bicarbonate transport by cultured rabbit inner medullary collecting duct cells.

作者信息

Weill A E, Tisher C C, Conde M F, Weiner I D

机构信息

Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville 32610.

出版信息

Am J Physiol. 1994 Mar;266(3 Pt 2):F466-76. doi: 10.1152/ajprenal.1994.266.3.F466.

Abstract

The inner medullary collecting duct (IMCD) is the final portion of the mammalian renal tubule that is able to significantly regulate systemic acid-base balance. Although the H+ transporters of this segment are relatively well studied, little is known regarding the mechanisms of HCO3- transport. The mechanisms of HCO3- transport in primary cultures of rabbit IMCD were studied using the pH-sensitive dye, 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein, in CO2/HCO3(-)-containing solutions at 37 degrees C. Removal of Cl- from the extracellular solution caused reversible intracellular alkalinization, demonstrating the presence of Cl-/HCO3- exchange. Alkalinization with Cl- removal was independent of changes in membrane potential, did not require the presence of extracellular Na+, and was inhibited by the disulfonic stilbene, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS, 10(-4) M). Half-maximal intracellular pH (pHi) recovery with readdition of Cl- to the extracellular solution occurred at a Cl- concentration of 37.4 +/- 5.7 mM. When rabbit IMCD were cultured on permeable support membranes, Cl-/HCO3- exchange activity was found only on the basolateral membrane. However, there was no evidence of band 3 protein immunoreactivity. In contrast, no evidence for Na(+)-(HCO3-)n > 1 cotransport activity was found. Depolarization of IMCD cells by acute increases in extracellular K+ did not alter pHi, nor was Na(+)-dependent, 5-(N-ethyl-N-isopropyl)amiloride-insensitive pHi recovery from an acid load inhibited by DIDS (10(-4) M). Finally, recovery from intracellular alkalosis induced by incubation in 0 mM Cl-, 50 mM HCO3- extracellular solution required Cl- and was independent of Na+. These studies indicate that the major mechanism of HCO3- transport in primary cultures of the rabbit IMCD is via a band 3 protein-negative, Na(+)-independent, basolateral, Cl-/HCO3- exchanger.

摘要

髓质内集合管(IMCD)是哺乳动物肾小管的最后一部分,能够显著调节全身酸碱平衡。尽管该节段的H⁺转运体已得到较为充分的研究,但关于HCO₃⁻转运机制却知之甚少。本研究使用pH敏感染料2',7'-双(2-羧乙基)-5(6)-羧基荧光素,在37℃含CO₂/HCO₃⁻的溶液中,对兔IMCD原代培养物中HCO₃⁻的转运机制进行了研究。从细胞外溶液中去除Cl⁻会导致细胞内可逆性碱化,表明存在Cl⁻/HCO₃⁻交换。去除Cl⁻引起的碱化与膜电位变化无关,不需要细胞外Na⁺的存在,并且被二磺酸芪4,4'-二异硫氰酸芪-2,2'-二磺酸(DIDS,10⁻⁴ M)抑制。当向细胞外溶液中重新添加Cl⁻时,细胞内pH(pHi)恢复到半最大值时的Cl⁻浓度为37.4±5.7 mM。当兔IMCD在可渗透支持膜上培养时,Cl⁻/HCO₃⁻交换活性仅在基底外侧膜上被发现。然而,没有证据表明存在带3蛋白免疫反应性。相反,未发现Na⁺-(HCO₃⁻)n>1共转运活性的证据。细胞外K⁺急性增加使IMCD细胞去极化,并未改变pHi,DIDS(10⁻⁴ M)也未抑制从酸负荷中恢复的Na⁺依赖性、5-(N-乙基-N-异丙基)氨氯地平不敏感的pHi。最后,在0 mM Cl⁻、50 mM HCO₃⁻细胞外溶液中孵育诱导的细胞内碱中毒的恢复需要Cl⁻,且与Na⁺无关。这些研究表明,兔IMCD原代培养物中HCO₃⁻转运的主要机制是通过一种不依赖Na⁺、位于基底外侧的带3蛋白阴性的Cl⁻/HCO₃⁻交换体。

相似文献

1
Mechanisms of bicarbonate transport by cultured rabbit inner medullary collecting duct cells.
Am J Physiol. 1994 Mar;266(3 Pt 2):F466-76. doi: 10.1152/ajprenal.1994.266.3.F466.
2
Basolateral Na(+)-independent Cl(-)-HCO3- exchange in primary cultures of rat IMCD cells.
Am J Physiol. 1992 Sep;263(3 Pt 2):F401-10. doi: 10.1152/ajprenal.1992.263.3.F401.
4
Cl-HCO3 exchange and Na-HCO3 symport in rabbit outer medullary collecting duct cells.
Am J Physiol. 1991 May;260(5 Pt 2):F635-42. doi: 10.1152/ajprenal.1991.260.5.F635.
5
Distribution of Cl-/HCO3- exchange and intercalated cells in rabbit cortical collecting duct.
Am J Physiol. 1994 Dec;267(6 Pt 2):F952-64. doi: 10.1152/ajprenal.1994.267.6.F952.
6
Intracellular pH regulation in rabbit S3 proximal tubule: basolateral Cl-HCO3 exchange and Na-HCO3 cotransport.
Am J Physiol. 1990 Feb;258(2 Pt 2):F371-81. doi: 10.1152/ajprenal.1990.258.2.F371.
8
Regulation of intracellular pH in two cell populations of inner stripe of rabbit outer medullary collecting duct.
Am J Physiol. 1993 Sep;265(3 Pt 2):F406-15. doi: 10.1152/ajprenal.1993.265.3.F406.

文献AI研究员

20分钟写一篇综述,助力文献阅读效率提升50倍。

立即体验

用中文搜PubMed

大模型驱动的PubMed中文搜索引擎

马上搜索

文档翻译

学术文献翻译模型,支持多种主流文档格式。

立即体验