scholarly journals Ultracytochemical localization of Ca2+-ATPase activity on the epithelial cells of rat trachea.

1982 ◽  
Vol 15 (6) ◽  
pp. 812-826 ◽  
Author(s):  
TAKAO ANDO ◽  
HIROSHI MAYAHARA ◽  
KAZUSHI FUJIMOTO ◽  
HIROAKI MIYAJIMA ◽  
KAZUO OGAWA
Keyword(s):  
Epithelial Cells ◽  
Atpase Activity ◽  
Rat Trachea

Anion-dependent Mg2+ influx and a role for a vacuolar H+-ATPase in sheep ruminal epithelial cells

2003 ◽  
Vol 285 (1) ◽  
pp. G45-G53 ◽  
Author(s):  
Monika Schweigel ◽  
Holger Martens
Keyword(s):  
Epithelial Cells ◽  
Atpase Activity ◽  
Primary Culture ◽  
Intracellular Ph ◽  
Uptake Rate ◽  
Ruminal Fermentation ◽  
Fermentation Products ◽  
Fluorescence Techniques ◽  
Transport Inhibitors ◽  
Stimulation Of

The K+-insensitive component of Mg2+ influx in primary culture of ruminal epithelial cells (REC) was examined by means of fluorescence techniques. The effects of extracellular anions, ruminal fermentation products, and transport inhibitors on the intracellular free Mg2+ concentration ([Mg2+]i), Mg2+ uptake, and intracellular pH were determined. Under control conditions (HEPES-buffered high-NaCl medium), the [Mg2+]i of REC increased from 0.56 ± 0.14 to 0.76 ± 0.06 mM, corresponding to a Mg2+ uptake rate of 15 μM/min. Exposure to butyrate did not affect Mg2+ uptake, but it was stimulated (by 84 ± 19%) in the presence of [Formula: see text]. In contrast, Mg2+ uptake was strongly diminished if REC were suspended in [Formula: see text]-buffered high-KCl medium (22.3 ± 4 μM/min) rather than in HEPES-buffered KCl medium (37.5 ± 6 μM/min). After switching from high- to low-Cl– solution, [Mg2+]i was reduced from 0.64 ± 0.09 to 0.32 ± 0.16 mM and the [Formula: see text]-stimulated Mg2+ uptake was completely inhibited. Bumetanide and furosemide blocked the rate of Mg2+ uptake by 64 and 40%, respectively. Specific blockers of vacuolar H+-ATPase reduced the [Mg2+]i (36%) and Mg2+ influx (38%) into REC. We interpret this data to mean that the K+-insensitive Mg2+ influx into REC is mediated by a cotransport of Mg2+ and Cl– and is energized by an H+-ATPase. The stimulation of Mg2+ transport by ruminal fermentation products may result from a modulation of the H+-ATPase activity.

scholarly journals Bitter tastants and artificial sweeteners activate a subset of epithelial cells in acute tissue slices of the rat trachea

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Chiara Lasconi ◽  
Simone Pifferi ◽  
Andres Hernandez-Clavijo ◽  
Flavia Merigo ◽  
Maria Paola Cecchini ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Artificial Sweeteners ◽  
Tissue Slices ◽  
Rat Trachea

Hormonal regulation of Na+-K+-ATPase in cultured epithelial cells

1986 ◽  
Vol 251 (2) ◽  
pp. C186-C190 ◽  
Author(s):  
J. P. Johnson ◽  
D. Jones ◽  
W. P. Wiesmann
Keyword(s):  
Enzyme Activity ◽  
Epithelial Cells ◽  
Atpase Activity ◽  
Hormonal Regulation ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Toad Urinary Bladder ◽  
A6 Cells ◽  
Cultured Epithelial Cells ◽  
Stimulation Of

Aldosterone and insulin stimulate Na+ transport through mechanisms involving protein synthesis. Na+-K+-ATPase has been implicated in the action of both hormones. We examined the effect of aldosterone and insulin on Na+-K+-ATPase in epithelial cells in culture derived from toad urinary bladder (TB6C) and toad kidney (A6). Aldosterone, but not insulin, increases short-circuit current (ISC) in TB6C cells. Aldosterone increases Na+-K+-ATPase activity after 18 h of incubation, but no effect can be seen at 3 and 6 h. Amiloride, which inhibits aldosterone-induced increases in ISC, has no effect on either basal or aldosterone stimulated enzyme activity. Both aldosterone and insulin increase ISC in A6 cells and when added together are synergistic. Aldosterone stimulates enzyme activity in A6 cells, but insulin alone has no effect. However, aldosterone and insulin together stimulate enzyme activity more than aldosterone alone. It appears that stimulation of Na+-K+-ATPase activity is involved in aldosterone action in both cell lines but does not appear to be due to increased Na+ entry, since enhanced enzyme activity is not inhibited by amiloride. In contrast, insulin alone has no direct effect on Na+-K+-ATPase, although the increased enzyme activity following both agents in combination may explain their synergism on ISC.

Glucose activates H+-ATPase in kidney epithelial cells

2004 ◽  
Vol 287 (1) ◽  
pp. C97-C105 ◽  
Author(s):  
Suguru Nakamura
Keyword(s):  
Epithelial Cells ◽  
Atpase Activity ◽  
Physiological Effect ◽  
Bicarbonate Transport ◽  
Epithelial Cell Line ◽  
Atpase Inhibitor ◽  
Concanamycin A ◽  
Vacuolar Acidification ◽  
Kidney Epithelial Cells ◽  
Effect Of Glucose

The vacuolar H+-ATPase (V-ATPase) acidifies compartments of the vacuolar system of eukaryotic cells. In renal epithelial cells, it resides on the plasma membrane and is essential for bicarbonate transport and acid-base homeostasis. The factors that regulate the H+-ATPase remain largely unknown. The present study examines the effect of glucose on H+-ATPase activity in the pig kidney epithelial cell line LLC-PK1. Cellular pH was measured by performing ratiometric fluorescence microscopy using the pH-sensitive indicator BCECF-AM. Intracellular acidification was induced with NH3/NH4+ prepulse, and rates of intracellular pH (pHi) recovery (after in situ calibration) were determined by the slopes of linear regression lines during the first 3 min of recovery. The solutions contained 1 μM ethylisopropylamiloride and were K+ free to eliminate Na+/H+ exchange and H+-K+-ATPase activity. After NH3/NH4+-induced acidification, LLC-PK1 cells had a significant pHi recovery rate that was inhibited entirely by 100 nM of the V-ATPase inhibitor concanamycin A. Acute removal of glucose from medium markedly reduced V-ATPase-dependent pHi recovery activity. Readdition of glucose induced concentration-dependent reactivation of V-ATPase pHi recovery activity within 2 min. Glucose replacement produced no significant change in cell ATP or ADP content. H+-ATPase activity was completely inhibited by the glycolytic inhibitor 2-deoxy-d-glucose (20 mM) but only partially inhibited by the mitochondrial electron transport inhibitor antimycin A (20 μM). The phosphatidylinositol 3-kinase (PI3K) inhibitor wortmannin (500 nM) abolished glucose activation of V-ATPase, and activity was restored after wortmannin removal. Glucose activates V-ATPase activity in kidney epithelial cells through the glycolytic pathway by a signaling pathway that requires PI3K activity. These findings represent an entirely new physiological effect of glucose, linking it to cellular proton secretion and vacuolar acidification.

Large Na+ influx and high Na+, K+–ATPase activity in mitochondria-rich epithelial cells of the inner ear endolymphatic sac

2006 ◽  
Vol 453 (6) ◽  
pp. 905-913 ◽  
Author(s):  
Takenori Miyashita ◽  
Hitoshi Tatsumi ◽  
Kimihide Hayakawa ◽  
Nozomu Mori ◽  
Masahiro Sokabe
Keyword(s):  
Epithelial Cells ◽  
Atpase Activity ◽  
Inner Ear ◽  
Endolymphatic Sac

scholarly journals Na,K-ATPase Activity Is Required for Formation of Tight Junctions, Desmosomes, and Induction of Polarity in Epithelial Cells

2001 ◽  
Vol 12 (12) ◽  
pp. 3717-3732 ◽  
Author(s):  
Sigrid A. Rajasekaran ◽  
Lawrence G. Palmer ◽  
Sun Y. Moon ◽  
Alejandro Peralta Soler ◽  
Gerard L. Apodaca ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Atpase Activity ◽  
Tight Junctions ◽  
Stress Fibers ◽  
Epithelial Polarity ◽  
Rhoa Gtpase ◽  
Key Enzyme ◽  
And Function ◽  
Atpase Inhibition ◽  
Darby Canine Kidney

Na,K-ATPase is a key enzyme that regulates a variety of transport functions in epithelial cells. In this study, we demonstrate a role for Na,K-ATPase in the formation of tight junctions, desmosomes, and epithelial polarity with the use of the calcium switch model in Madin-Darby canine kidney cells. Inhibition of Na,K-ATPase either by ouabain or potassium depletion prevented the formation of tight junctions and desmosomes and the cells remained nonpolarized. The formation of bundled stress fibers that appeared transiently in control cells was largely inhibited in ouabain-treated or potassium-depleted cells. Failure to form stress fibers correlated with a large reduction of RhoA GTPase activity in Na,K-ATPase-inhibited cells. In cells overexpressing wild-type RhoA GTPase, Na,K-ATPase inhibition did not affect the formation of stress fibers, tight junctions, or desmosomes, and epithelial polarity developed normally, suggesting that RhoA GTPase is an essential component downstream of Na,K-ATPase-mediated regulation of these junctions. The effects of Na,K-ATPase inhibition were mimicked by treatment with the sodium ionophore gramicidin and were correlated with the increased intracellular sodium levels. Furthermore, ouabain treatment under sodium-free condition did not affect the formation of junctions and epithelial polarity, suggesting that the intracellular Na+ homeostasis plays a crucial role in generation of the polarized phenotype of epithelial cells. These results thus demonstrate that the Na,K-ATPase activity plays an important role in regulating both the structure and function of polarized epithelial cells.

Long-term terbutaline exposure stimulates α1-Na+-K+-ATPase expression at posttranscriptional level in rat fetal distal lung epithelial cells

2010 ◽  
Vol 298 (1) ◽  
pp. L96-L104 ◽  
Author(s):  
Muhammad S. Rahman ◽  
Shephali Gandhi ◽  
Gail Otulakowski ◽  
Wenming Duan ◽  
Aparna Sarangapani ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Atpase Activity ◽  
Apical Membrane ◽  
Short Circuit ◽  
Basolateral Membrane ◽  
Lung Epithelial Cells ◽  
Intracellular Camp ◽  
Adult Type ◽  
Lung Epithelial ◽  
Distal Lung

Transepithelial Na+ transport through epithelial Na+ channels (ENaC) on the apical membrane and Na+-K+-ATPase activity on the basolateral membrane of distal lung epithelial cells are critical for alveolar fluid clearance. Acute exposure to β-adrenergic agonists stimulates lung fluid clearance by increasing Na+ transport. We investigated the effects of chronic exposure to the β2-adrenergic agonist terbutaline on the transepithelial Na+ transport in rat fetal distal lung epithelia (FDLE). FDLE monolayers exposed to 10−4 M terbutaline for 48 h had significantly increased propanolol-blockable transepithelial total and amiloride-sensitive short-circuit current ( Isc); however, when these chronically exposed monolayers were acutely exposed to additional β-agonists and intracellular cAMP upregulators, there was no further increase in Isc. Monolayers exposed to terbutaline for >48 h had Isc similar to control cells. Ouabain-sensitive Na+-K+-ATPase activity was increased in 48-h terbutaline-exposed FDLE whose apical membranes were permeabilized with nystatin. In contrast, terbutaline did not increase amiloride-sensitive apical membrane Isc in FDLE whose basolateral membranes were permeabilized with nystatin. Terbutaline treatment did not affect α-, β-, or γ-ENaC mRNA or α-ENaC protein steady-state levels, but increased total cellular levels and rate of synthesis of α1-Na+-K+-ATPase protein in FDLE in the absence of any change in α1-Na+-K+-ATPase mRNA. Total cellular β1-Na+-K+-ATPase mRNA and protein levels were not affected by terbutaline. These data suggest that FDLE have different responses from adult type II epithelial cells when chronically exposed to terbutaline, and their increased transepithelial Na+ transport occurs via a posttranscriptional increase in α1-Na+-K+-ATPase expression.

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