SO039BETA3-ADRENORECEPTOR AS A NEW PLAYER IN SYMPATHETIC REGULATION OF THE ACID-BASE HOMEOSTASIS IN THE KIDNEY

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Serena Milano ◽  
Andrea Gerbino ◽  
Monica Carmosino ◽  
Maria Svelto ◽  
Giuseppe Procino
Keyword(s):  
Atpase Activity ◽  
Physiological Role ◽  
Mouse Kidney ◽  
Hormonal Control ◽  
Resting Cells ◽  
Atpase Inhibitor ◽  
Acid Base ◽  
Urine Ph ◽  
Knock Out ◽  
Mouse Urine

Abstract Background and Aims Sympathetic nervous system has a key role in the regulation of renal function. We previously showed that, in mouse, the β3-adrenoreceptor (β3-AR) localizes in most of the nephron segments and its selective agonism promotes a potent antidiuretic effect. Here, we evaluate the expression of β3-AR in kidney intercalated cells (ICs) which are associated with the regulation of acid-base homeostasis in distal segments of the kidney tubule. The aim of this study is to investigate whether the β3-AR might play a role in the acid-base homeostasis operated by the kidney. Method The β3-AR expression in mouse kidney ICs was investigated by confocal microscopy. Wild type (wt) and β3-AR knock-out (ko) mice were used to study the role of β3-AR in the renal acid-base homeostasis. Mouse urine were collected using metabolic cages and pH was measured. Immunofluorescence and Western blotting experiments were performed to evaluate the localization and the abundance of renal H+-ATPase in wt and β3-AR ko mice. Kidney cells expressing human β3-AR (M1-β3-AR) and endogenous H+-ATPase were used to investigate the possible effects of β3-AR stimulation on the activity/localization of H+-ATPase. Live imaging experiments using the pH-sensitive dye BCECF were carried out to determine intracellular pH and assess H+-ATPase activity.  Immunofluorescence experiments were performed to reveal the effects of β3-AR activation on H+-ATPase localization. Results Co-localization study of β3-AR with either H+-ATPase or Cl−/HCO3− exchanger pendrin in mouse kidney showed that β3-AR is expressed in H+-secreting type A, in HCO3— secreting type B, and in non-A non-B ICs. The urine pH of β3-AR ko mice was significantly higher compared with wt mice. In line with these results, localization and expression analysis showed that renal H+-ATPase significantly decreased in β3-AR ko mice compared to wt mice, supporting the idea that H+ secretion is partially blunted in these animals. Of note, exposure of M1-β3-AR cells to a selective β3-AR agonist induced a 2.5 fold increase of H+-ATPase activity compared to resting cells and this effect was prevented by a selective β3-AR antagonist or by the H+-ATPase inhibitor bafilomycin. Moreover, β3-AR agonism enhanced H+-ATPase apical expression in M1-β3-AR cells. In addition, the PKA inhibitor H89 abolished the stimulatory effect of β3-AR agonism, demonstrating the involvement of the cAMP/PKA pathway. Conclusion The present data suggest that modulation of H+-ATPase activity in renal ICs by endogenous β3-AR agonists may play an addition physiological role in hormonal control of renal acid-base homeostasis.

Inhibition of muscle actomyosin ATPase activity by mitochondrial ATPase inhibitor

1977 ◽  
Vol 75 (4) ◽  
pp. 1104-1110 ◽  
Author(s):  
Shojiro Yamazaki ◽  
Hiroshi Hasebe ◽  
Haruhiko Takisawa ◽  
Yutaka Tamaura ◽  
Yuji Inada
Keyword(s):  
Atpase Activity ◽  
Mitochondrial Atpase ◽  
Atpase Inhibitor ◽  
Actomyosin Atpase

Effects of bafilomycin A1 on cytosolic pH of sheep alveolar and peritoneal macrophages: evaluation of the pH-regulatory role of plasma membrane V-ATPases.

1995 ◽  
Vol 198 (8) ◽  
pp. 1711-1715 ◽  
Author(s):  
T A Heming ◽  
D L Traber ◽  
F Hinder ◽  
A Bidani
Keyword(s):  
Plasma Membrane ◽  
Atpase Activity ◽  
Initial Rate ◽  
Cell Types ◽  
Peritoneal Macrophages ◽  
Bafilomycin A1 ◽  
Atpase Inhibitor ◽  
Cytosolic Ph ◽  
Phi Regulation

The role of plasma membrane V-ATPase activity in the regulation of cytosolic pH (pHi) was determined for resident alveolar and peritoneal macrophages (m theta) from sheep. Cytosolic pH was measured using 2',7'-biscarboxyethyl-5,6-carboxyfluorescein (BCECF). The baseline pHi of both cell types was sensitive to the specific V-ATPase inhibitor bafilomycin A1. Bafilomycin A1 caused a significant (approximately 0.2 pH units) and rapid (within seconds) decline in baseline pHi. Further, bafilomycin A1 slowed the initial rate of pHi recovery (dpHi/dt) from intracellular acid loads. Amiloride had no effects on baseline pHi, but reduced dpHi/dt (acid-loaded pHi nadir < 6.8) by approximately 35%. Recovery of pHi was abolished by co-treatment of m theta with bafilomycin A1 and amiloride. These data indicate that plasma membrane V-ATPase activity is a major determinant of pHi regulation in resident alveolar and peritoneal m theta from sheep. Sheep m theta also appear to possess a Na+/H+ exchanger. However, Na+/H+ exchange either is inactive or can be effectively masked by V-ATPase-mediated H+ extrusion at physiological pHi values.

Impact of hydrogen ion on fasting ketogenesis: feedback regulation of acid production

1982 ◽  
Vol 242 (3) ◽  
pp. F238-F245 ◽  
Author(s):  
V. L. Hood ◽  
E. Danforth ◽  
E. S. Horton ◽  
R. L. Tannen
Keyword(s):  
Acid Production ◽  
Metabolic Regulation ◽  
Feedback Regulation ◽  
Hydrogen Ion ◽  
Acid Excretion ◽  
Acid Base Balance ◽  
Acid Base ◽  
Urine Ph ◽  
Ion Production ◽  
Base Balance

To determine whether acid-base balance regulates hydrogen ion production, seven obese volunteers were given NaHCO3 and NH4Cl (2 mmol.kg-1.day-1) during two separate 7-day fasts. On days 5-7 plasma bicarbonate was lower in the NH4Cl fasts (14.0 +/- 1.4 mM) than in the NaHCO3 fasts (18.3 +/- 1.1 mM), while urine pH and net acid excretion did not differ. Acid production (acid excretion minus intake) was greater by 204 mmol/day in the NaHCO3 fasts (274 +/- 16 mmol/day) than in the NH4Cl fasts (70 +/- 19 mmol/day). Ketoacid excretion, which reflected net ketoacid production, paralleled acid production, decreasing from 213 +/- 24 mmol/day in the NaHCO3 fasts to 67 +/- 18 mmol/day in the NH4Cl fasts. Thus, during starvation, alterations in hydrogen ion intake and the associated changes in acid-base balance modify the net production of endogenous acid by influencing the synthesis or utilization of ketoacids. Although the specific site of this metabolic regulation is undefined, these results indicate that systemic acid-base status can exert feedback control over hydrogen ion production.

Role of organic anions in renal response to dietary acid and base loads

1989 ◽  
Vol 257 (2) ◽  
pp. F170-F176 ◽  
Author(s):  
J. C. Brown ◽  
R. K. Packer ◽  
M. A. Knepper
Keyword(s):  
Organic Anion ◽  
Organic Anions ◽  
Acid Excretion ◽  
Acid Base Balance ◽  
Acid Base ◽  
Urine Ph ◽  
Renal Response ◽  
Base Balance ◽  
Net Acid Excretion

Bicarbonate is formed when organic anions are oxidized systemically. Therefore, changes in organic anion excretion can affect systemic acid-base balance. To assess the role of organic anions in urinary acid-base excretion, we measured urinary excretion in control rats, NaHCO3-loaded rats, and NH4Cl-loaded rats. Total organic anions were measured by the titration method of Van Slyke. As expected, NaHCO3 loading increased urine pH and decreased net acid excretion (NH4+ + titratable acid - HCO3-), whereas NH4Cl loading had the opposite effect. Organic anion excretion was increased in response to NaHCO3 loading and decreased in response to NH4Cl loading. We quantified the overall effect of organic ion plus inorganic buffer ion excretion on acid-base balance. The amounts of organic anions excreted by all animals in this study were greater than the amounts of NH4+, HCO3-, or titratable acidity excreted. In addition, in response to acid and alkali loading, changes in urinary organic anion excretion were 40-50% as large as changes in net acid excretion. We conclude that, in rats, regulation of organic anion excretion can contribute importantly to the overall renal response to acid-base disturbances.

scholarly journals Effect of Simulated Matches on Post-Exercise Biochemical Parameters in Women’s Indoor and Beach Handball

2020 ◽  
Vol 17 (14) ◽  
pp. 5046
Author(s):  
Joanna Kamińska ◽  
Tomasz Podgórski ◽  
Jakub Kryściak ◽  
Maciej Pawlak
Keyword(s):  
Blood Parameters ◽  
Ion Concentration ◽  
Electrolyte Balance ◽  
Acid Base Balance ◽  
Acid Base ◽  
Urine Ph ◽  
Physically Active ◽  
Post Exercise ◽  
Before And After ◽  
Base Balance

This study assesses the status of hydration and the acid-base balance in female handball players in the Polish Second League before and after simulated matches in both indoor (hall) and beach (outdoor) conditions. The values of biochemical indicators useful for describing water-electrolyte management, such as osmolality, hematocrit, aldosterone, sodium, potassium, calcium, chloride and magnesium, were determined in the players’ fingertip capillary blood. Furthermore, the blood parameters of the acid-base balance were analysed, including pH, standard base excess, lactate and bicarbonate ion concentration. Additionally, the pH and specific gravity of the players’ urine were determined. The level of significance was set at p < 0.05. It was found that both indoor and beach simulated matches caused post-exercise changes in the biochemical profiles of the players’ blood and urine in terms of water-electrolyte and acid-base balance. Interestingly, the location of a simulated match (indoors vs. beach) had a statistically significant effect on only two of the parameters measured post-exercise: concentration of calcium ions (lower indoors) and urine pH (lower on the beach). A single simulated game, regardless of its location, directly affected the acid-base balance and, to a smaller extent, the water-electrolyte balance, depending mostly on the time spent physically active during the match.

Regulation of AQP6 mRNA and protein expression in rats in response to altered acid-base or water balance

2000 ◽  
Vol 279 (6) ◽  
pp. F1014-F1026 ◽  
Author(s):  
Dominique Promeneur ◽  
Tae-Hwan Kwon ◽  
Masato Yasui ◽  
Gheun-Ho Kim ◽  
Jørgen Frøkiær ◽  
...  
Keyword(s):  
Water Balance ◽  
Mrna Expression ◽  
Water Intake ◽  
Collecting Duct ◽  
Free Access ◽  
Protein Abundance ◽  
Acid Base ◽  
Urine Ph ◽  
Daily Water Intake ◽  
Acid Load

In the rat, aquaporin-6 (AQP6) is mainly localized in intercalated cells (ICs) in collecting ducts, where it is exclusively associated with intracellular vesicles. In this study, we examined whether AQP6 protein and mRNA expression were regulated in the inner medulla or inner stripe of the outer medulla. Rats treated with dietary alkali or acid load for 7 days with a fixed daily water intake revealed appropriate changes in urine pH but unchanged urine output. AQP6 protein and mRNA abundance were increased in alkali-loaded rats (187 ± 18 and 151 ± 17% of control, respectively), whereas no changes were observed in acid-loaded rats. Immunohistochemistry revealed increased IC AQP6 labeling in alkali-loaded rats but not in acid-loaded rats. In contrast, administration of NH4Cl in the drinking water for 2 wk (free access to water) revealed a significant increase in AQP6 protein abundance (194 ± 9% of control), but this was associated with increased water intake. Combined, this suggests that AQP6 expression was not affected by acid loading per se but rather was in response to changes in water intake. Consistent with this, water loading for 48 h was associated with increased AQP6 protein abundance, compared with thirsted rats. Moreover, rats with lithium-induced nephrogenic diabetes insipidus had a threefold increase in both AQP6 protein and mRNA expression. Overall, these results suggest that AQP6 expression in collecting duct ICs is regulated by altered acid/alkali load or water balance. Thus AQP6 may contribute to maintenance of acid-base homeostasis and water balance.

scholarly journals Urine pH is an indicator of dietary acid–base load, fruit and vegetables and meat intakes: results from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk population study

2008 ◽  
Vol 99 (6) ◽  
pp. 1335-1343 ◽  
Author(s):  
Ailsa A. Welch ◽  
Angela Mulligan ◽  
Sheila A. Bingham ◽  
Kay-tee Khaw
Keyword(s):  
Fruit And Vegetables ◽  
Fruit And Vegetable ◽  
Acid Base Balance ◽  
Acid Base ◽  
Urine Ph ◽  
Alkaline Urine ◽  
Base Balance ◽  
Dietary Acid ◽  
Base Load ◽  
Prospective Investigation

Evidence exists that a more acidic diet is detrimental to bone health. Although more precise methods exist for measurement of acid–base balance, urine pH reflects acid–base balance and is readily measurable but has not been related to habitual dietary intake in general populations. The present study investigated the relationship between urine pH and dietary acid–base load (potential renal acid load; PRAL) and its contributory food groups (fruit and vegetables, meats, cereal and dairy foods). There were 22 034 men and women aged 39–78 years living in Norfolk (UK) with casual urine samples and dietary intakes from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk FFQ. A sub-study (n 363) compared pH in casual samples and 24 h urine and intakes from a 7 d diary and the FFQ. A more alkaline diet (low PRAL), high fruit and vegetable intake and lower consumption of meat was significantly associated with a more alkaline urine pH before and after adjustment for age, BMI, physical activity and smoking habit and also after excluding for urinary protein, glucose, ketones, diagnosed high blood pressure and diuretic medication. In the sub-study the strongest relationship was found between the 24 h urine and the 7 d diary. In conclusion, a more alkaline diet, higher fruit and vegetable and lower meat intake were related to more alkaline urine with a magnitude similar to intervention studies. As urine pH relates to dietary acid–base load its use to monitor change in consumption of fruit and vegetables, in individuals, warrants further investigation.

scholarly journals Muscarinic acetylcholine receptor activation induces Ca2+ mobilization and Na+/K+-ATPase activity inhibition in eel enterocytes

2002 ◽  
Vol 173 (2) ◽  
pp. 325-334 ◽  
Author(s):  
A Muscella ◽  
S Greco ◽  
MG Elia ◽  
E Jimenez ◽  
C Storelli ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Muscarinic Acetylcholine Receptor ◽  
Specific Inhibitor ◽  
Fold Increase ◽  
Receptor Activation ◽  
Free Medium ◽  
Atpase Inhibitor ◽  
Extracellular Medium ◽  
Calphostin C ◽  
Dose Dependent

The effect of carbachol (Cch) on intracellular calcium concentration ([Ca2+]i) in eel enterocytes was examined using the fluorescent Ca2+ indicator fura-2. Cch caused a biphasic increase in [Ca2+]i, with an initial spike followed by a progressively decreasing level (over 6 min) to the initial, pre-stimulated, level. The effect of Cch was dose-dependent with a 7.5-fold increase in [Ca2+]i over basal level induced by the maximal dose of Cch (100 microM). In Ca2+-free/EGTA buffer the effect of Cch was less pronounced and the [Ca2+]i returned rapidly to basal levels. The increment of [Ca2+]i was dose-dependently attenuated in cells pre-treated with U73122, a specific inhibitor of phospholipase C, suggesting that the Cch-stimulated increment of [Ca2+]i required inositol triphosphate formation. In the presence of extracellular Ca2+, thapsigargin (TG), a specific microsomal Ca2+-ATPase inhibitor, caused a sustained rise in [Ca2+]i whereas in Ca2+-free medium the increase in [Ca2+]i was transient; in both cases, subsequent addition of Cch was without effect. When 2 mM CaCl2 were added to the cells stimulated with TG or with Cch in Ca2+-free medium, a rapid increase in [Ca2+]i was detected, corresponding to the capacitative Ca2+ entry. Thus, both TG and Cch depleted intracellular Ca2+ stores and stimulated influx of extracellular Ca2+ consistent with capacitative Ca2+ entry. K+ depolarization obtained with increasing concentrations of KCl in the extracellular medium induced a dose-related increase in [Ca2+]i which was blocked by 2 microM nifedipine, a non-specific L-type Ca2+ channel blocker. Nifedipine also changed significantly the height of the Ca2+ transient, and the rate of decrement to the pre-stimulated [Ca2+]i level, indicating that Ca2+ entry into enterocytes also occurs through an L-type voltage-dependent calcium channel pathway. We also show that isolated enterocytes stimulated with increasing Cch concentrations (0.1-1000 microM) showed a dose-dependent inhibition of the Na+/K+-ATPase activity. The threshold decrease was at 1 microM Cch; it reached a maximum at 100 microM (50.5% inhibition) and did not decrease further with the use of higher dose. The effect of Cch on Na+/K+-ATPase activity was dependent on both protein kinase C (PKC) and protein phosphatase calcineurin activation since the PKC inhibitor calphostin C abolished Cch effects, while the calcineurin inhibitor FK506 augmented Cch effect. Collectively, these data establish a functional pathway by which Cch can modulate the activity of the Na+/K+-ATPase through a PKC-dependent (calphostin C-sensitive) pathway and a calcineurin-dependent (FK506-sensitive) pathway.

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.

scholarly journals The adenosine triphosphatase-inhibitor content of bovine heart submitochondrial particles. Influence of the inhibitor on adenosine triphosphate-dependent reactions

1977 ◽  
Vol 162 (2) ◽  
pp. 351-357 ◽  
Author(s):  
S J Ferguson ◽  
D A Harris ◽  
G K Radda
Keyword(s):  
Atpase Activity ◽  
Adenosine Triphosphatase ◽  
Type I ◽  
Type Ii ◽  
Inhibitor Protein ◽  
Isolation Method ◽  
Atpase Inhibitor ◽  
Submitochondrial Particles ◽  
Bovine Heart ◽  
Tightly Bound Nucleotides

1. The activity of the ATPase (adenosine triphosphatase) of phosphorylating particles prepared by sonication of bovine heart mitochondria in the presence of MgCl2 and ATP is influenced by the isolation method for the mitochondria used in the preparation of particles. Type-I particles, made from mitochondria isolated in a medium lacking succinate, have a lower ATPase activity than to Type-II particles, which are prepared from mitochondria isolated in a medium containing succinate. 2. Centrifugation under appropriate energized conditions increases the ATPase activity of Type-I particles almost to that of the Type-II particles. The ATPase activity of Type-II particles was only slightly stimulated by this procedure. These data are interpreted as indicating a higher content of the ATPase-inhibitor protein in the Type-I particles. 3. A comparison was made of the ATP-driven enhancement of 8-anilinonaphthalene-1-sulphonate fluorescence and the exchange of the endogenous tightly bound nucleotides of the ATPase in Type-I and Type-II particles. The effect of exogenous inhibitor protein on both these reactions was also studied. 4. The time-scale on which the inhibitor protein can exchange between ATPase molecules is discussed.

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