Cellular response to acute respiratory acidosis in rat medullary collecting duct

1983 ◽  
Vol 245 (6) ◽  
pp. F670-F679 ◽  
Author(s):  
K. M. Madsen ◽  
C. C. Tisher
Keyword(s):  
Plasma Membrane ◽  
Surface Density ◽  
Collecting Duct ◽  
Respiratory Acidosis ◽  
Hydrogen Ion ◽  
Apical Plasma Membrane ◽  
Apical Region ◽  
Intercalated Cells ◽  
Ion Secretion ◽  
Medullary Collecting Duct

The collecting duct of the mammalian kidney is involved in urine acidification. Recent studies in the turtle bladder suggest that hydrogen ion secretion in response to elevated CO2 is regulated by insertion of hydrogen pumps into the luminal membrane of the mitochondria-rich cells. Because intercalated cells of the collecting duct are structurally similar to mitochondria-rich cells of the amphibian bladder, we studied the rat outer medullary collecting duct (OMCD) during respiratory acidosis to determine whether changes compatible with hydrogen ion secretion occur in the intercalated cells. Rats were studied during normal acid-base conditions and after 4-5 h of respiratory acidosis. After collection of physiologic data, the kidneys were fixed by in vivo perfusion and processed for electron microscopy. No changes were observed in the principal cells of the OMCD. Morphometric analysis revealed a significant increase in the surface density of the apical plasma membrane and a decrease in the number of tubulovesicular profiles in the apical region of the intercalated cells throughout the OMCD with respiratory acidosis. There were no changes in surface density of the basolateral membrane. These findings suggest that in response to respiratory acidosis there is transport of membrane from the tubulovesicular membrane compartment to the apical plasma membrane of the intercalated cells.

Importance of medullary events in ammonium excretion: studies in acute respiratory and acute metabolic acidosis

1983 ◽  
Vol 61 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Andre Gougoux ◽  
Patrick Vinay ◽  
Guy Lemieux ◽  
Marc Goldstein ◽  
Bobby Stinebaugh ◽  
...  
Keyword(s):  
Metabolic Acidosis ◽  
Collecting Duct ◽  
Respiratory Acidosis ◽  
Renal Medulla ◽  
Hydrogen Ion ◽  
Ammonium Excretion ◽  
Urine Ph ◽  
Ion Secretion ◽  
Medullary Collecting Duct ◽  
Acute Metabolic Acidosis

The renal medulla can play an important role in acid excretion by modulating both hydrogen ion secretion in the medullary collecting duct and the medullary [Formula: see text]. The purpose of these experiments was to characterize the intrarenal events associated with ammonium excretion in acute acidosis. Cortical events were monitored in two ways: first, the rates of glutamine extraction and ammoniagenesis were assessed by measuring arteriovenous differences and the rate of renal blood flow; second, the biochemical response of the ammoniagenesis pathway was examined by measuring glutamate and 2-oxoglutarate, key renal cortical metabolites in this pathway. There were no significant differences noted in any of these cortical parameters between acute respiratory and metabolic acidosis. Despite a comparable twofold rise in ammonium excretion in both cases, the urine pH, [Formula: see text], and the urine minus blood [Formula: see text] difference (U-B [Formula: see text]) were lower during acute hypercapnia. In these experiments, the urine [Formula: see text] was 34 mmHg (1 mmHg = 133.322 Pa) lower than that of the blood during acute respiratory acidosis while the U-B [Formula: see text] was 5 ± 3 mmHg in acute metabolic acidosis. Thus there were significant differences in medullary events during these two conditions. Although the urine pH is critical in determining ammonium excretion in certain circumstances, these results suggest that regional variations in the medullary [Formula: see text] can modify this relationship.

scholarly journals Immunolocalization of the secretory isoform of Na-K-Cl cotransporter in rat renal intercalated cells.

1996 ◽  
Vol 7 (12) ◽  
pp. 2533-2542 ◽  
Author(s):  
S M Ginns ◽  
M A Knepper ◽  
C A Ecelbarger ◽  
J Terris ◽  
X He ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Collecting Duct ◽  
Rat Kidney ◽  
Apical Plasma Membrane ◽  
Thick Ascending Limb ◽  
Intercalated Cells ◽  
Specific Affinity ◽  
Basolateral Plasma Membrane ◽  
Medullary Collecting Duct ◽  
Antipeptide Antibody

Two bumetanide-sensitive ion cotransporters that carry Na+, K+, and Cl- in a coupled fashion have been identified. One type, the "absorptive" isoform, carries these ions across the apical plasma membrane of the thick ascending limb of Henle's loop. Another isoform, the "secretory" cotransporter, has been identified in a number of epithelial tissues by physiological means, but its sites of expression in the kidney have not been fully characterized. Complementary DNA believed to code for the secretory isoform (called "BSC2" or "NKCC1") have recently been cloned. This study used a specific affinity-purified antipeptide antibody to this protein for immunolocalization in the rat kidney. Immunoblot studies using this antibody show abundant immunoreactivity against bands of 140-190 and 120 kd in the parotid gland, colon, and stomach, sites where the secretory form of the cotransporter has been identified by physiological techniques. This distribution supports the hypothesis that this isoform represents the secretory form of the cotransporter. Studies in the kidney revealed that the same bands are associated with membrane fractions chiefly in the outer medulla. Immunolocalizations show that immunoreactivity is selectively and intensely localized to the basolateral plasma membrane of a subfraction of outer medullary collecting duct cells. An independently produced monoclonal antibody (T4) specific for Na-K-Cl cotransporter displays the same localization. Dual localizations of cotransporter antibody with respect to antibody specific for principal cells (aquaporin-2) and intercalated cells (band 3 and H(+)-ATPase) show that cotransporter immunoreactivity is localized to alpha-intercalated cells of the outer medullary collecting duct in the rat. This distinctive localization suggests that the secretory form of the cotransporter may play a role in renal NH4+ and/or acid secretion by this cell type.

H(+)V-ATPase-dependent luminal acidification in the kidney collecting duct and the epididymis/vas deferens: vesicle recycling and transcytotic pathways

2000 ◽  
Vol 203 (1) ◽  
pp. 137-145 ◽  
Author(s):  
D. Brown ◽  
S. Breton
Keyword(s):  
Plasma Membrane ◽  
B Cells ◽  
Vas Deferens ◽  
Collecting Duct ◽  
Kidney Cortex ◽  
Apical Plasma Membrane ◽  
Intercalated Cells ◽  
A Cells ◽  
Basolateral Plasma Membrane ◽  
Intracellular Vesicles

Many vertebrate transporting epithelia contain characteristic ‘mitochondria-rich’ cells that express high levels of a vacuolar proton-pumping ATPase (H(+)V-ATPase) on their plasma membrane and on intracellular vesicles. In the kidney cortex, A-cells and B-cells are involved in proton secretion and bicarbonate secretion, respectively, in the distal nephron and collecting duct. A-cells have an H(+)V-ATPase on their apical plasma membrane and on intracellular vesicles, whereas the cellular location of the H(+)V-ATPase can be apical, basolateral, bipolar or diffuse in B-cells. The rat epididymis and vas deferens also contain a distinct population of H(+)V-ATPase-rich epithelial cells. These cells are involved in generating a low luminal pH, which is involved in sperm maturation and in maintaining sperm in an immotile state during their passage through the epididymis and vas deferens. In both kidney and reproductive tract, H(+)V-ATPase-rich cells have a high rate of apical membrane recycling. H(+)V-ATPase molecules are transported between the cell surface and the cytoplasm in vesicles that have a well-defined ‘coat’ structure formed of the peripheral V(1) subunits of the H(+)V-ATPase. In addition, we propose that B-type intercalated cells have a transcytotic pathway that enables them to shuttle H(+)V-ATPase molecules from apical to basolateral plasma membrane domains. This hypothesis is supported by data showing that A-cells and B-cells have different intracellular trafficking pathways for LGP120, a lysosomal glycoprotein. LGP120 was found both on the basolateral plasma membrane and in lysosomes in B-cells, whereas no LGP120 was detectable in the plasma membrane of A-cells. We propose that the ‘polarity reversal’ of the H(+)V-ATPase in B-intercalated cells is mediated by a physiologically regulated transcytotic pathway that may be similar to that existing in some other cell types.

Activation of acid-secreting intercalated cells in rabbit collecting duct with ammonium chloride loading

1994 ◽  
Vol 266 (4) ◽  
pp. F633-F645 ◽  
Author(s):  
J. W. Verlander ◽  
K. M. Madsen ◽  
J. K. Cannon ◽  
C. C. Tisher
Keyword(s):  
Plasma Membrane ◽  
Morphometric Analysis ◽  
Collecting Duct ◽  
Band 3 ◽  
Apical Plasma Membrane ◽  
Multivesicular Bodies ◽  
Intercalated Cells ◽  
Cytoplasmic Vesicles ◽  
Basolateral Plasma Membrane ◽  
Acid Loading

In normal rabbit, immunolabeling of intercalated cells in the outer medullary collecting duct (OMCD) demonstrates band 3-like protein in the basolateral plasma membrane (15) and H(+)-adenosinetriphosphatase (H(+)-ATPase) in the apical plasma membrane and cytoplasmic vesicles (30). However, in type A intercalated cells in the cortical collecting duct (CCD), band 3-like protein is located primarily in multivesicular bodies and cytoplasmic vesicles (15), whereas H(+)-ATPase is present in cytoplasmic vesicles only in most intercalated cells (30). In this study, we observed the effect of chronic acid loading on immunolocalization of these transporters in the collecting duct. Adult New Zealand White rabbits received either normal tap water (controls) or 75 mM NH4Cl for 12 days plus eight daily gavages of 2-6 meq NH4Cl/kg body wt. At time of death, mean urine pH of acid-loaded animals was 5.96 (SD = 0.69), vs. 8.47 (SD = 0.07) in controls. Kidneys were fixed by in vivo perfusion and processed for light and electron microscopic immunoperoxidase localization of band 3-like protein and immunogold localization of H(+)-ATPase. In controls, band 3-like protein was largely confined to multivesicular bodies in the majority of positive-staining intercalated cells in the CCD and to the basolateral plasma membrane of intercalated cells in the OMCD. In acid-loaded rabbits, band 3 protein-positive intercalated cells in the inner CCD and the in the outer stripe of the OMCD (OMCDo) were strikingly stellate in form. Basolateral plasma membrane label was intensified, while the number of labeled multivesicular bodies was diminished. Morphometric analysis demonstrated an increase in the amount of basolateral plasma membrane in these intercalated cells. In control rabbits, H(+)-ATPase immunoreactivity in intercalated cells in the CCD was located predominantly over cytoplasmic vesicles. A minority of intercalated cells exhibited basolateral plasma membrane label, and only an occasional cell displayed apical plasma membrane label. In acid-loaded rabbits, H(+)-ATPase immunoreactivity was enhanced along the apical plasma membrane of intercalated cells in the inner CCD, and morphometric analysis demonstrated increased apical plasma membrane in band 3-positive intercalated cells in this segment. These results suggest that rabbits respond to acid loading via enhancement of both electrogenic proton secretion and Cl-/HCO3- exchange in intercalated cells in the inner CCD and the OMCDo.

Membrane recycling and epithelial cell function

1989 ◽  
Vol 256 (1) ◽  
pp. F1-F12 ◽  
Author(s):  
D. Brown
Keyword(s):  
Plasma Membrane ◽  
Cell Function ◽  
Collecting Duct ◽  
Water Channel ◽  
Cell Types ◽  
Apical Plasma Membrane ◽  
Proton Pumps ◽  
Intercalated Cells ◽  
Membrane Recycling ◽  
Membrane Composition

The plasma membrane composition of virtually all eucaryotic cells is established, maintained, and modified by the process of membrane recycling. Specific plasma membrane components are inserted by exocytosis of transport vesicles, and are removed by endocytosis of segments of the membrane in which particular proteins are concentrated. In the kidney collecting duct, vasopressin induces the cycling of vesicles that are thought to carry water channels to and from the apical plasma membrane of principal cells, thus modulating the water permeability of this membrane. In the intercalated cells of the collecting duct, hydrogen ion secretion is controlled by the recycling of vesicles carrying proton pumps to and from the plasma membrane. In both cell types, "coated" carrier vesicles are involved, but whereas clathrin-coated vesicles participate in water channel recycling, the vesicles in intercalated cells are coated with the cytoplasmic domains of proton pumps. Following a brief outline of membrane recycling in general, this review summarizes previous data on membrane recycling in the collecting duct and related transporting epithelia and discusses some selected points relating to the role of membrane recycling and cell-specific function in the collecting duct.

scholarly journals Syntaxin specificity of aquaporins in the inner medullary collecting duct

2009 ◽  
Vol 297 (2) ◽  
pp. F292-F300 ◽  
Author(s):  
Abinash C. Mistry ◽  
Rickta Mallick ◽  
Janet D. Klein ◽  
Thomas Weimbs ◽  
Jeff M. Sands ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Collecting Duct ◽  
Water Channel ◽  
Snare Complex ◽  
Apical Plasma Membrane ◽  
Transport Activity ◽  
Inner Medullary Collecting Duct ◽  
Syntaxin 4 ◽  
Medullary Collecting Duct ◽  
Syntaxin 3

Proper targeting of the aquaporin-2 (AQP2) water channel to the collecting duct apical plasma membrane is critical for the urine concentrating mechanism and body water homeostasis. However, the trafficking mechanisms that recruit AQP2 to the plasma membrane are still unclear. Snapin is emerging as an important mediator in the initial interaction of trafficked proteins with target soluble N-ethylmaleimide-sensitive factor attachment protein (SNAP) receptor (t-SNARE) proteins, and this interaction is functionally important for AQP2 regulation. We show that in AQP2-Madin-Darby canine kidney cells subjected to adenoviral-mediated expression of both snapin and syntaxins, the association of AQP2 with both syntaxin-3 and syntaxin-4 is highly enhanced by the presence of snapin. In pull-down studies, snapin detected AQP2, syntaxin-3, syntaxin-4, and SNAP23 from the inner medullary collecting duct. AQP2 transport activity, as probed by AQP2's urea permeability, was greatly enhanced in oocytes that were coinjected with cRNAs of SNARE components (snapin+syntaxin-3+SNAP23) over those injected with AQP2 cRNA alone. It was not enhanced when syntaxin-3 was replaced by syntaxin-4 (snapin+syntaxin-4+SNAP23). On the other hand, the latter combination significantly enhanced the transport activity of the related AQP3 water channel while the presence of syntaxin-3 did not. This AQP-syntaxin interaction agrees with the polarity of these proteins' expression in the inner medullary collecting duct epithelium. Thus our findings suggest a selectivity of interactions between different aquaporin and syntaxin isoforms, and thus in the regulation of AQP2 and AQP3 activities in the plasma membrane. Snapin plays an important role as a linker between the water channel and the t-SNARE complex, leading to the fusion event, and the pairing with specific t-SNAREs is essential for the specificity of membrane recognition and fusion.

Immunocytochemical and immunoelectron microscopic localization of α-, β-, and γ-ENaC in rat kidney

2001 ◽  
Vol 280 (6) ◽  
pp. F1093-F1106 ◽  
Author(s):  
Henrik Hager ◽  
Tae-Hwan Kwon ◽  
Anna K. Vinnikova ◽  
Shyama Masilamani ◽  
Heddwen L. Brooks ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Confocal Microscopy ◽  
Subcellular Localization ◽  
Collecting Duct ◽  
Rat Kidney ◽  
Apical Plasma Membrane ◽  
Cortical Collecting Duct ◽  
Principal Cells ◽  
Medullary Collecting Duct ◽  
Epithelial Sodium Channel Enac

Epithelial sodium channel (ENaC) subunit (α, β, and γ) mRNA and protein have been localized to the principal cells of the connecting tubule (CNT), cortical collecting duct (CCD), and outer medullary collecting duct (OMCD) in rat kidney. However, the subcellular localization of ENaC subunits in the principal cells of these cells is undefined. The cellular and subcellular localization of ENaC subunits in rat kidney was therefore examined. Immunocytochemistry demonstrated the presence of all three subunits in principal cells of the CNT, CCD, OMCD, and IMCD. In cortex and outer medulla, confocal microscopy demonstrated a difference in the subcellular localization of subunits. α-ENaC was localized mainly in a zone in the apical domains, whereas β- and γ-ENaC were found throughout the cytoplasm. Immunoelectron microscopy confirmed the presence of ENaC subunits in both the apical plasma membrane and intracellular vesicles. In contrast to the labeling pattern seen in cortex, α-ENaC labeling in IMCD cells was distributed throughout the cytoplasm. In the urothelium covering pelvis, ureters, and bladder, immunoperoxidase and confocal microscopy revealed differences the presence of all ENaC subunits. As seen in CCD, α-ENaC was present in a narrow zone near the apical plasma membrane, whereas β- and γ-ENaC were dispersed throughout the cytoplasm. In conclusion, all three subunits of ENaC are expressed throughout the collecting duct (CD), including the IMCD as well as in the urothelium. The intracellular vesicular pool in CD principal cells suggests ENaC trafficking as a potential mechanism for the regulation of Na+ reabsorption.

Increased expression of H+-ATPase in inner medullary collecting duct of aquaporin-1-deficient mice

2003 ◽  
Vol 285 (3) ◽  
pp. F550-F557 ◽  
Author(s):  
Young-Hee Kim ◽  
Jin Kim ◽  
A. S. Verkman ◽  
Kirsten M. Madsen
Keyword(s):  
Kidney Development ◽  
De Novo ◽  
Collecting Duct ◽  
Apical Plasma Membrane ◽  
Intercalated Cells ◽  
Wild Type ◽  
Urinary Ph ◽  
Aquaporin 1 ◽  
Inner Medullary Collecting Duct ◽  
Medullary Collecting Duct

Phenotype analysis has demonstrated that aquaporin-1 (AQP1) null mice are polyuric and manifest a urinary concentrating defect because of an inability to create a hypertonic medullary interstitium. We report here that deletion of AQP1 is also associated with a decrease in urinary pH from 6.15 ± (SE) 0.1 to 5.63 ± 0.07. To explore the mechanism of the decrease in urinary pH, we examined the expression of H+-ATPase in kidneys of AQP1 null mice. There was strong labeling for H+-ATPase in intercalated cells and proximal tubule cells in both AQP1 null and wild-type mice. Strong H+-ATPase immunostaining was also present in the apical plasma membrane of inner medullary collecting duct (IMCD) cells in AQP1 null mice, whereas no H+-ATPase labeling was observed in IMCD cells in wild-type mice. In addition, there was an increase in the prevalence of type A intercalated cells in the IMCD of AQP1 null mice, suggesting that the deletion of intercalated cells from the IMCD, which normally occurs during postnatal kidney development, was impaired. Western blot analysis of H+-ATPase expression in the different regions of the kidney demonstrated a significant increase in H+-ATPase protein in the inner medulla of AQP1 null mice compared with wild-type mice. There were no changes in H+-ATPase expression in the cortex or outer medulla. These results represent the first demonstration of apical H+-ATPase immunoreactivity in IMCD cells in vivo and suggest that the decrease in urinary pH observed in AQP1 null mice is due to upregulation of H+-ATPase in the IMCD. The induction of H+-ATPase expression in IMCD cells of AQP1 null mice may be related to the chronically low interstitial osmolality in these animals. The challenge will be to identify the molecular signal(s) responsible for the de novo H+-ATPase expression.

Intracellular band 3 immunostaining in type A intercalated cells of rabbit kidney

1992 ◽  
Vol 262 (6) ◽  
pp. F1015-F1022
Author(s):  
K. M. Madsen ◽  
J. Kim ◽  
C. C. Tisher
Keyword(s):  
Plasma Membrane ◽  
Collecting Duct ◽  
Basolateral Membrane ◽  
Type A ◽  
Band 3 ◽  
Rabbit Kidney ◽  
Apical Plasma Membrane ◽  
Intercalated Cells ◽  
Cortical Collecting Duct ◽  
Electron Microscopic

Intercalated cells (ICs) in the collecting duct and the connecting tubule (CNT) are involved in H+ secretion and HCO3- reabsorption. H+ secretion is mediated by an H(+)-adenosinetriphosphatase in the apical plasma membrane, whereas a band 3-like Cl(-)-HCO3- exchanger in the basolateral membrane is responsible for HCO3- reabsorption. Recent studies have reported that a band 3-like protein is also present in mitochondria in rabbit ICs. The purpose of this study was to establish the subcellular location of the band 3-like Cl(-)-HCO3- exchanger in rabbit ICs by electron microscopic immunocytochemistry using a monoclonal antibody, IVF12, against erythrocyte band 3 protein. Rabbit kidneys were preserved by in vivo perfusion with a paraformaldehyde-lysine-periodate solution and processed for immunocytochemistry using a horseradish peroxidase preembedding technique. Band 3 immunostaining was observed on the basolateral plasma membrane of ICs in the outer medullary collecting duct and type A cells in the cortical collecting duct (CCD) and CNT. In addition, distinct staining for band 3 was present in numerous small vesicles and in multivesicular bodies in type A ICs in the CCD and CNT. However, there was no evidence of band 3 immunostaining of mitochondria or of the apical plasma membrane in any cells of the collecting duct. These observations suggest that basolateral Cl(-)-HCO3- exchangers in type A ICs in the rabbit kidney are stored in intracellular vesicles and possibly degraded in the vascular-lysosomal system when these cells are in a resting state. The previously reported band 3 immunolabeling of mitochondria could not be confirmed.

Forskolin stimulates phosphorylation and membrane accumulation of UT-A3

2007 ◽  
Vol 293 (4) ◽  
pp. F1308-F1313 ◽  
Author(s):  
Mitsi A. Blount ◽  
Janet D. Klein ◽  
Christopher F. Martin ◽  
Dmitry Tchapyjnikov ◽  
Jeff M. Sands
Keyword(s):  
Plasma Membrane ◽  
Plasma Membranes ◽  
Apical Membrane ◽  
Collecting Duct ◽  
Rat Kidney ◽  
Basolateral Membrane ◽  
Apical Plasma Membrane ◽  
Membrane Staining ◽  
Protein Protein Interaction ◽  
Medullary Collecting Duct

UT-A1 is regulated by vasopressin and is localized to the apical membrane and intracellular compartment of inner medullary collecting duct (IMCD) cells. UT-A3 is also expressed in the IMCD and is regulated by forskolin in heterologous systems. The goal of the present study is to investigate mechanisms by which vasopressin regulates UT-A3 in rat IMCD. In fresh suspensions of rat IMCD, forskolin increases the phosphorylation of UT-A3, similar to UT-A1. Biotinylation studies indicate that UT-A3 is located in the plasma membrane. Forskolin treatment increases the abundance of UT-A3 in the plasma membrane similar to UT-A1. However, these two transporters do not form a complex through a protein-protein interaction, suggesting that transporter function is unique to each protein. While immunohistochemistry localized UT-A3 to the basal and lateral membranes, a majority of the staining was cytosolic. Immunohistochemistry of vasopressin-treated rat kidney sections also localized UT-A3 primarily to the cytosol with basal and lateral membrane staining but also showed some apical membrane staining in some IMCD cells. This suggests that under normal conditions, UT-A3 functions as the basolateral transporter but in a high cAMP environment, the transporter may move from the cytosol to all plasma membranes to increase urea flux in the IMCD. In summary, this study confirms that UT-A3 is located in the inner medullary tip where it is expressed in the basolateral membrane, shows that UT-A3 is a phosphoprotein in rat IMCD that can be trafficked to the plasma membrane independent of UT-A1, and suggests that vasopressin may induce UT-A3 expression in the apical plasma membrane of IMCD.

Sign in / Sign up

Export Citation Format

Share Document