1
|
Kemp BA, Howell NL, Gildea JJ, Hinkle JD, Shabanowitz J, Hunt DF, Conaway MR, Keller SR, Carey RM. Evidence That Binding of Cyclic GMP to the Extracellular Domain of NKA (Sodium-Potassium ATPase) Mediates Natriuresis. Circ Res 2023; 132:1127-1140. [PMID: 36919600 PMCID: PMC10171454 DOI: 10.1161/circresaha.122.321693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 03/07/2023] [Indexed: 03/16/2023]
Abstract
BACKGROUND Extracellular renal interstitial guanosine cyclic 3',5'-monophosphate (cGMP) inhibits renal proximal tubule (RPT) sodium (Na+) reabsorption via Src (Src family kinase) activation. Through which target extracellular cGMP acts to induce natriuresis is unknown. We hypothesized that cGMP binds to the extracellular α1-subunit of NKA (sodium-potassium ATPase) on RPT basolateral membranes to inhibit Na+ transport similar to ouabain-a cardiotonic steroid. METHODS Urine Na+ excretion was measured in uninephrectomized 12-week-old female Sprague-Dawley rats that received renal interstitial infusions of vehicle (5% dextrose in water), cGMP (18, 36, and 72 μg/kg per minute; 30 minutes each), or cGMP+rostafuroxin (12 ng/kg per minute) or were subjected to pressure-natriuresis±rostafuroxin infusion. Rostafuroxin is a digitoxigenin derivative that displaces ouabain from NKA. RESULTS Renal interstitial cGMP and raised renal perfusion pressure induced natriuresis and increased phosphorylated SrcTyr416 and Erk 1/2 (extracellular signal-regulated protein kinase 1/2)Thr202/Tyr204; these responses were abolished with rostafuroxin coinfusion. To assess cGMP binding to NKA, we performed competitive binding studies with isolated rat RPTs using bodipy-ouabain (2 μM)+cGMP (10 µM) or rostafuroxin (10 µM) and 8-biotin-11-cGMP (2 μM)+ouabain (10 μM) or rostafuroxin (10 µM). cGMP or rostafuroxin reduced bodipy-ouabain fluorescence intensity, and ouabain or rostafuroxin reduced 8-biotin-11-cGMP staining. We cross-linked isolated rat RPTs with 4-N3-PET-8-biotin-11-cGMP (2 μM); 8-N3-6-biotin-10-cAMP served as negative control. Precipitation with streptavidin beads followed by immunoblot analysis showed that RPTs after cross-linking with 4-N3-PET-8-biotin-11-cGMP exhibited a significantly stronger signal for NKA than non-cross-linked samples and cross-linked or non-cross-linked 8-N3-6-biotin-10-cAMP RPTs. Ouabain (10 μM) reduced NKA in cross-linked 4-N3-PET-8-biotin-11-cGMP RPTs confirming fluorescence staining. 4-N3-PET-8-biotin-11-cGMP cross-linked samples were separated by SDS gel electrophoresis and slices corresponding to NKA molecular weight excised and processed for mass spectrometry. NKA was the second most abundant protein with 50 unique NKA peptides covering 47% of amino acids in NKA. Molecular modeling demonstrated a potential cGMP docking site in the ouabain-binding pocket of NKA. CONCLUSIONS cGMP can bind to NKA and thereby mediate natriuresis.
Collapse
Affiliation(s)
- Brandon A Kemp
- Department of Medicine, Division of Endocrinology and Metabolism (B.A.K., N.L.H., S.R.K., R.M.C.), University of Virginia, Charlottesville
| | - Nancy L Howell
- Department of Medicine, Division of Endocrinology and Metabolism (B.A.K., N.L.H., S.R.K., R.M.C.), University of Virginia, Charlottesville
| | - John J Gildea
- Department of Pathology (J.J.G.), University of Virginia, Charlottesville
| | - Josh D Hinkle
- Department of Chemistry (J.D.H., J.S., D.F.H.), University of Virginia, Charlottesville
| | - Jeffrey Shabanowitz
- Department of Chemistry (J.D.H., J.S., D.F.H.), University of Virginia, Charlottesville
| | - Donald F Hunt
- Department of Chemistry (J.D.H., J.S., D.F.H.), University of Virginia, Charlottesville
| | - Mark R Conaway
- Division of Translational Research and Applied Statistics, Department of Public Health Sciences (M.R.C.), University of Virginia, Charlottesville
| | - Susanna R Keller
- Department of Medicine, Division of Endocrinology and Metabolism (B.A.K., N.L.H., S.R.K., R.M.C.), University of Virginia, Charlottesville
| | - Robert M Carey
- Department of Medicine, Division of Endocrinology and Metabolism (B.A.K., N.L.H., S.R.K., R.M.C.), University of Virginia, Charlottesville
| |
Collapse
|
2
|
Leipziger J, Praetorius H. Renal Autocrine and Paracrine Signaling: A Story of Self-protection. Physiol Rev 2020; 100:1229-1289. [PMID: 31999508 DOI: 10.1152/physrev.00014.2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Autocrine and paracrine signaling in the kidney adds an extra level of diversity and complexity to renal physiology. The extensive scientific production on the topic precludes easy understanding of the fundamental purpose of the vast number of molecules and systems that influence the renal function. This systematic review provides the broader pen strokes for a collected image of renal paracrine signaling. First, we recapitulate the essence of each paracrine system one by one. Thereafter the single components are merged into an overarching physiological concept. The presented survey shows that despite the diversity in the web of paracrine factors, the collected effect on renal function may not be complicated after all. In essence, paracrine activation provides an intelligent system that perceives minor perturbations and reacts with a coordinated and integrated tissue response that relieves the work load from the renal epithelia and favors diuresis and natriuresis. We suggest that the overall function of paracrine signaling is reno-protection and argue that renal paracrine signaling and self-regulation are two sides of the same coin. Thus local paracrine signaling is an intrinsic function of the kidney, and the overall renal effect of changes in blood pressure, volume load, and systemic hormones will always be tinted by its paracrine status.
Collapse
Affiliation(s)
- Jens Leipziger
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; and Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus, Denmark
| | - Helle Praetorius
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; and Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus, Denmark
| |
Collapse
|
3
|
Effects of Nitric Oxide on Renal Proximal Tubular Na + Transport. BIOMED RESEARCH INTERNATIONAL 2017; 2017:6871081. [PMID: 29181400 PMCID: PMC5664255 DOI: 10.1155/2017/6871081] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 09/14/2017] [Indexed: 12/28/2022]
Abstract
Nitric oxide (NO) has a wide variety of physiological functions in the kidney. Besides the regulatory effects in intrarenal haemodynamics and glomerular microcirculation, in vivo studies reported the diuretic and natriuretic effects of NO. However, opposite results showing the stimulatory effect of NO on Na+ reabsorption in the proximal tubule led to an intense debate on its physiological roles. Animal studies have showed the biphasic effect of angiotensin II (Ang II) and the overall inhibitory effect of NO on the activity of proximal tubular Na+ transporters, the apical Na+/H+ exchanger isoform 3, basolateral Na+/K+ ATPase, and the Na+/HCO3− cotransporter. However, whether these effects could be reproduced in humans remained unclear. Notably, our recent functional analysis of isolated proximal tubules demonstrated that Ang II dose-dependently stimulated human proximal tubular Na+ transport through the NO/guanosine 3′,5′-cyclic monophosphate (cGMP) pathway, confirming the human-specific regulation of proximal tubular transport via NO and Ang II. Of particular importance for this newly identified pathway is its possibility of being a human-specific therapeutic target for hypertension. In this review, we focus on NO-mediated regulation of proximal tubular Na+ transport, with emphasis on the interaction with individual Na+ transporters and the crosstalk with Ang II signalling.
Collapse
|
4
|
Gonzalez-Vicente A, Garvin JL. Effects of Reactive Oxygen Species on Tubular Transport along the Nephron. Antioxidants (Basel) 2017; 6:antiox6020023. [PMID: 28333068 PMCID: PMC5488003 DOI: 10.3390/antiox6020023] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/15/2017] [Accepted: 03/18/2017] [Indexed: 12/17/2022] Open
Abstract
Reactive oxygen species (ROS) are oxygen-containing molecules naturally occurring in both inorganic and biological chemical systems. Due to their high reactivity and potentially damaging effects to biomolecules, cells express a battery of enzymes to rapidly metabolize them to innocuous intermediaries. Initially, ROS were considered by biologists as dangerous byproducts of respiration capable of causing oxidative stress, a condition in which overproduction of ROS leads to a reduction in protective molecules and enzymes and consequent damage to lipids, proteins, and DNA. In fact, ROS are used by immune systems to kill virus and bacteria, causing inflammation and local tissue damage. Today, we know that the functions of ROS are not so limited, and that they also act as signaling molecules mediating processes as diverse as gene expression, mechanosensation, and epithelial transport. In the kidney, ROS such as nitric oxide (NO), superoxide (O₂-), and their derivative molecules hydrogen peroxide (H₂O₂) and peroxynitrite (ONO₂-) regulate solute and water reabsorption, which is vital to maintain electrolyte homeostasis and extracellular fluid volume. This article reviews the effects of NO, O₂-, ONO₂-, and H₂O₂ on water and electrolyte reabsorption in proximal tubules, thick ascending limbs, and collecting ducts, and the effects of NO and O₂- in the macula densa on tubuloglomerular feedback.
Collapse
Affiliation(s)
- Agustin Gonzalez-Vicente
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
- Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires C1113AAD, Argentina.
| | - Jeffrey L Garvin
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
| |
Collapse
|
5
|
Abstract
Cyclic GMP (cGMP) is a ubiquitous intracellular second messenger that mediates a wide spectrum of physiologic processes in multiple cell types within the cardiovascular and nervous systems. Synthesis of cGMP occurs either by NO-sensitive guanylyl cyclases in response to nitric oxide or by membrane-bound guanylyl cyclases in response to natriuretic peptides and has been shown to regulate blood pressure homeostasis by influencing vascular tone, sympathetic nervous system, and sodium and water handling in the kidney. Several cGMPs degrading phosphodiesterases (PDEs), including PDE1 and PDE5, play an important role in the regulation of cGMP signaling. Recent findings revealed that increased activity of cGMP-hydrolyzing PDEs contribute to the development of hypertension. In this review, we will summarize recent research findings regarding the cGMP/PDE signaling in the vasculature, the central nervous system, and the kidney which are associated with the development and maintenance of hypertension.
Collapse
Affiliation(s)
- Evanthia Mergia
- Department of Pharmacology and Toxicology, Ruhr-University Bochum, Bochum, Germany
| | - Johannes Stegbauer
- Department of Nephrology, Medical Faculty, University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany.
| |
Collapse
|
6
|
Srisawat U, Kongrat S, Muanprasat C, Chatsudthipong V. Losartan and Sodium Nitroprusside Effectively Protect against Renal Impairments after Ischemia and Reperfusion in Rats. Biol Pharm Bull 2016; 38:753-62. [PMID: 25947921 DOI: 10.1248/bpb.b14-00860] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ischemia and subsequent reperfusion are known to impair renal function. We examined several agents that might prevent renal impairment or enhance the recovery of renal function after ischemia/reperfusion injury in rats. Different degrees of preventive effects were observed in rats treated with captopril, BQ-123 (endothelin type A receptor antagonist), sodium nitroprusside (SNP, a nitric oxide donor), and losartan (angiotensin II type 1 receptor antagonist). Only minimal changes in renal morphology were observed after treatment with losartan, SNP, captopril, and BQ-123 compared with control animals. On the other hand, lesions were prominent in the N(G)-nitro-L-arginine-methyl ester (L-NAME)- and L-arginine-treated rats. The Na(+)-K(+) ATPase activity of ischemic kidneys was, however, preserved in all treatment groups, except in those treated with L-arginine and L-NAME, which showed a marked reduction in Na(+)-K(+) ATPase activity. Our post-treatment data suggest that losartan and SNP have the greatest potential for therapeutic use to mitigate post-ischemic renal damage and functional impairment.
Collapse
Affiliation(s)
- Umarat Srisawat
- Department of Physiology, Faculty of Science, Mahidol University
| | | | | | | |
Collapse
|
7
|
Ramseyer VD, Ortiz PA, Carretero OA, Garvin JL. Angiotensin II-mediated hypertension impairs nitric oxide-induced NKCC2 inhibition in thick ascending limbs. Am J Physiol Renal Physiol 2016; 310:F748-F754. [PMID: 26887831 PMCID: PMC4835923 DOI: 10.1152/ajprenal.00473.2015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 02/05/2016] [Indexed: 01/13/2023] Open
Abstract
In thick ascending limbs (THALs), nitric oxide (NO) decreases NaCl reabsorption via cGMP-mediated inhibition of Na-K-2Cl cotransporter (NKCC2). In angiotensin (ANG II)-induced hypertension, endothelin-1 (ET-1)-induced NO production by THALs is impaired. However, whether this alters NO's natriuretic effects and the mechanisms involved are unknown. In other cell types, ANG II augments phosphodiesterase 5 (PDE5)-mediated cGMP degradation. We hypothesized that NO-mediated inhibition of NKCC2 activity and stimulation of cGMP synthesis are blunted via PDE5 in ANG II-induced hypertension. Sprague-Dawley rats were infused with vehicle or ANG II (200 ng·kg-1·min-1) for 5 days. ET-1 reduced NKCC2 activity by 38 ± 13% (P < 0.05) in THALs from vehicle-treated rats but not from ANG II-hypertensive rats (Δ: -9 ± 13%). A NO donor yielded similar results as ET-1. In contrast, dibutyryl-cGMP significantly decreased NKCC2 activity in both vehicle-treated and ANG II-hypertensive rats (control: Δ-44 ± 15% vs. ANG II Δ-41 ± 10%). NO increased cGMP by 2.08 ± 0.36 fmol/μg protein in THALs from vehicle-treated rats but only 1.06 ± 0.25 fmol/μg protein in ANG II-hypertensive rats (P < 0.04). Vardenafil (25 nM), a PDE5 inhibitor, restored NO's ability to inhibit NKCC2 activity in THALs from ANG II-hypertensive rats (Δ: -60 ± 9%, P < 0.003). Similarly, NO's stimulation of cGMP was also restored by vardenafil (vehicle-treated: 1.89 ± 0.71 vs. ANG II-hypertensive: 2.02 ± 0.32 fmol/μg protein). PDE5 expression did not differ between vehicle-treated and ANG II-hypertensive rats. We conclude that NO-induced inhibition of NKCC2 and increases in cGMP are blunted in ANG II-hypertensive rats due to PDE5 activation. Defects in the response of THALs to NO may enhance NaCl retention in ANG II-induced hypertension.
Collapse
Affiliation(s)
- Vanesa D Ramseyer
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Health System, Detroit, Michigan;
- Department of Physiology, School of Medicine, Wayne State University, Detroit, Michigan; and
| | - Pablo A Ortiz
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Health System, Detroit, Michigan
- Department of Physiology, School of Medicine, Wayne State University, Detroit, Michigan; and
| | - Oscar A Carretero
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Health System, Detroit, Michigan
| | - Jeffrey L Garvin
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Health System, Detroit, Michigan
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio
| |
Collapse
|
8
|
Wu P, Gao Z, Ye S, Qi Z. Nitric oxide inhibits basolateral 10-pS Cl - channels through the cGMP/PKG signaling pathway in the thick ascending limb of C57BL/6 mice. Am J Physiol Renal Physiol 2016; 310:F755-F762. [PMID: 26764200 DOI: 10.1152/ajprenal.00270.2015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 01/07/2016] [Indexed: 11/22/2022] Open
Abstract
We used patch-clamp techniques to examine whether nitric oxide (NO) decreases NaCl reabsorption by suppressing basolateral 10-pS Cl- channels in the thick ascending limb (TAL). Both the NO synthase substrate l-arginine (l-Arg) and the NO donor S-nitroso-N-acetylpenicillamine significantly inhibited 10-pS Cl- channel activity in the TAL. The inhibitory effect of l-Arg on Cl- channels was completely abolished in the presence of the NO synthase inhibitor or NO scavenger. Moreover, inhibition of soluble guanylyl cyclase abrogated the effect of l-Arg on Cl- channels, whereas the cGMP analog 8-bromo-cGMP (8-BrcGMP) mimicked the effect of l-Arg and significantly decreased 10-pS Cl- channel activity, indicating that NO inhibits basolateral Cl- channels by increasing cGMP production. Furthermore, treatment of the TAL with a PKG inhibitor blocked the effect of l-Arg and 8-BrcGMP on Cl- channels, respectively. In contrast, a phosphodiesterase 2 inhibitor had no significant effect on l-Arg or 8-BrcGMP-induced inhibition of Cl- channels. Therefore, we conclude that NO decreases basolateral 10-pS Cl- channel activity through a cGMP-dependent PKG pathway, which may contribute to the natriuretic and diuretic effects of NO in vivo.
Collapse
Affiliation(s)
- Peng Wu
- Department of Basic Medical Sciences, Medical College, Xiamen University, Xiamen, China
| | - Zhongxiuzi Gao
- Department of Basic Medical Sciences, Medical College, Xiamen University, Xiamen, China
| | - Shiwei Ye
- Department of Basic Medical Sciences, Medical College, Xiamen University, Xiamen, China
| | - Zhi Qi
- Department of Basic Medical Sciences, Medical College, Xiamen University, Xiamen, China
| |
Collapse
|
9
|
Monzon CM, Garvin JL. Nitric oxide decreases the permselectivity of the paracellular pathway in thick ascending limbs. Hypertension 2015; 65:1245-50. [PMID: 25895589 DOI: 10.1161/hypertensionaha.115.05356] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 03/19/2015] [Indexed: 12/22/2022]
Abstract
Thick ascending limbs reabsorb 25% to 30% of the filtered NaCl. About 50% to 70% is reabsorbed via the transcellular pathway and 30% to 50% is reabsorbed through the Na-selective paracellular pathway. Nitric oxide (NO) inhibits transepithelial Na reabsorption, but its effects on the paracellular pathway are unknown. We hypothesized that NO decreases the selectivity of the paracellular pathway in thick ascending limbs via cGMP-dependent protein kinase. To assess relative Na/Cl permeability ratios (PNa/PCl), we perfused rat thick ascending limbs and measured the effect of reducing bath NaCl on transepithelial voltage, creating dilution potentials, with vehicle, NO donors, and endogenous NO. PNa/PCl was calculated using the Goldman-Hodgkin-Katz equation. Reducing bath Na/Cl to 16/8, 32/24, and 64/56 mmol/L created dilution potentials of -13.6±2.2, -10.8±3.0, and -6.1±0.9 mV, respectively. Calculated PNa/PCls were 2.0±0.2, 2.2±0.5, and 1.9±0.2. The NO donor spermine NONOate (200 µmol/L) blunted the dilution potential caused by 32/24 mmol/L Na/Cl from -11.1±2.1 to -6.5±1.6 mV (P<0.004) and PNa/PCl from 2.2±0.4 to 1.5±0.2. Nitroglycerin (200 µmol/L), another NO donor, also reduced PNa/PCl. Controls showed no significant changes. Dibutyryl-cGMP decreased dilution potentials from -13.4±2.9 to -7.5±1.8 mV (n=6; P<0.01). cGMP-dependent protein kinase inhibition with KT5823 (4 µmol/L) blocked the effect of spermine NONOate, whereas phosphodiesterase 2 inhibition did not. Endogenously produced NO mimicked the effect of the NO donors. In conclusion, NO reduces the selectivity of the paracellular pathway in thick ascending limbs via cGMP and cGMP-dependent protein kinase.
Collapse
Affiliation(s)
- Casandra M Monzon
- From the Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH
| | - Jeffrey L Garvin
- From the Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH.
| |
Collapse
|
10
|
Singh VP, Singh N, Jaggi AS. A review on renal toxicity profile of common abusive drugs. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2013; 17:347-57. [PMID: 23946695 PMCID: PMC3741492 DOI: 10.4196/kjpp.2013.17.4.347] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 06/25/2013] [Accepted: 07/14/2013] [Indexed: 12/22/2022]
Abstract
Drug abuse has become a major social problem of the modern world and majority of these abusive drugs or their metabolites are excreted through the kidneys and, thus, the renal complications of these drugs are very common. Morphine, heroin, cocaine, nicotine and alcohol are the most commonly abused drugs, and their use is associated with various types of renal toxicity. The renal complications include a wide range of glomerular, interstitial and vascular diseases leading to acute or chronic renal failure. The present review discusses the renal toxicity profile and possible mechanisms of commonly abused drugs including morphine, heroin, cocaine, nicotine, caffeine and alcohol.
Collapse
Affiliation(s)
- Varun Parkash Singh
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala-147002, India
| | | | | |
Collapse
|
11
|
Ramseyer VD, Garvin JL. Tumor necrosis factor-α: regulation of renal function and blood pressure. Am J Physiol Renal Physiol 2013; 304:F1231-42. [PMID: 23515717 DOI: 10.1152/ajprenal.00557.2012] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Tumor necrosis factor-α (TNF-α) is a pleiotropic cytokine that becomes elevated in chronic inflammatory states such as hypertension and diabetes and has been found to mediate both increases and decreases in blood pressure. High levels of TNF-α decrease blood pressure, whereas moderate increases in TNF-α have been associated with increased NaCl retention and hypertension. The explanation for these disparate effects is not clear but could simply be due to different concentrations of TNF-α within the kidney, the physiological status of the subject, or the type of stimulus initiating the inflammatory response. TNF-α alters renal hemodynamics and nephron transport, affecting both activity and expression of transporters. It also mediates organ damage by stimulating immune cell infiltration and cell death. Here we will summarize the available findings and attempt to provide plausible explanations for such discrepancies.
Collapse
Affiliation(s)
- Vanesa D Ramseyer
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, MI 48202, USA.
| | | |
Collapse
|
12
|
Pravdic D, Vladic N, Cavar I, Bosnjak ZJ. Effect of nitric oxide donors S-nitroso-N-acetyl-DL-penicillamine, spermine NONOate and propylamine propylamine NONOate on intracellular pH in cardiomyocytes. Clin Exp Pharmacol Physiol 2013; 39:772-8. [PMID: 22703333 DOI: 10.1111/j.1440-1681.2012.05734.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
1. Previous studies suggest that exogenous nitric oxide (NO) and NO-dependent signalling pathways modulate intracellular pH (pH(i)) in different cell types, but the role of NO in pH(i) regulation in the heart is poorly understood. Therefore, in the present study we investigated the effect of the NO donors S-nitroso-N-acetyl-DL-penicillamine, spermine NONOate and propylamine propylamine NONOate on pH(i) in rat isolated ventricular myocytes. 2. Cells were isolated from the hearts of adult Wistar rats and pH(i) was monitored using the pH-sensitive fluorescent indicator 5-(and-6)-carboxy seminaphtharhodafluor (SNARF)-1 (10 μmol/L) and a confocal microscope. To test the effect of NO donors on the Na⁺/H⁺ exchanger (NHE), basal pH(i) in Na⁺-free buffer and pH(i) recovery from intracellular acidosis after an ammonium chloride (10 mmol/L) prepulse were monitored. The role of carbonic anhydrase was tested using acetazolamide (50 μmol/L). 4,4-Diisothiocyanatostilbene-2,2'-disulphonic acid (0.5 mmol/L; DIDS) was used to inhibit the Cl⁻/OH⁻ and Cl⁻/HCO₃-exchangers. Acetazolamide and DIDS were applied via the superfusion system 1 and 5 min before the NO donors. 3. All three NO donors acutely decreased pH(i) and this effect persisted until the NO donor was removed. In Na⁺-free buffer, the decrease in basal pH(i) was increased, whereas inhibition of carbonic anhydrase and Cl⁻/OH⁻ and Cl⁻/HCO₃⁻ exchangers did not alter the effects of the NO donors on pH(i). After an ammonium preload, pH(i) recovery was accelerated in the presence of the NO donors. 4. In conclusion, exogenous NO decreases basal pH(i), leading to increased NHE activity. Carbonic anhydrase and chloride-dependent sarcolemmal HCO₃⁻ and OH⁻ transporters are not involved in the NO-induced decrease in pH(i) in rat isolated ventricular myocytes.
Collapse
Affiliation(s)
- Danijel Pravdic
- Department of Anaesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA.
| | | | | | | |
Collapse
|
13
|
Lessa LMA, Carraro-Lacroix LR, Crajoinas RO, Bezerra CN, Dariolli R, Girardi ACC, Fonteles MC, Malnic G. Mechanisms underlying the inhibitory effects of uroguanylin on NHE3 transport activity in renal proximal tubule. Am J Physiol Renal Physiol 2012; 303:F1399-408. [PMID: 22952280 DOI: 10.1152/ajprenal.00385.2011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
We previously demonstrated that uroguanylin (UGN) significantly inhibits Na(+)/H(+) exchanger (NHE)3-mediated bicarbonate reabsorption. In the present study, we aimed to elucidate the molecular mechanisms underlying the action of UGN on NHE3 in rat renal proximal tubules and in a proximal tubule cell line (LLC-PK(1)). The in vivo studies were performed by the stationary microperfusion technique, in which we measured H(+) secretion in rat renal proximal segments, through a H(+)-sensitive microelectrode. UGN (1 μM) significantly inhibited the net of proximal bicarbonate reabsorption. The inhibitory effect of UGN was completely abolished by either the protein kinase G (PKG) inhibitor KT5823 or by the protein kinase A (PKA) inhibitor H-89. The effects of UGN in vitro were found to be similar to those obtained by microperfusion. Indeed, we observed that incubation of LLC-PK(1) cells with UGN induced an increase in the intracellular levels of cAMP and cGMP, as well as activation of both PKA and PKG. Furthermore, we found that UGN can increase the levels of NHE3 phosphorylation at the PKA consensus sites 552 and 605 in LLC-PK(1) cells. Finally, treatment of LLC-PK(1) cells with UGN reduced the amount of NHE3 at the cell surface. Overall, our data suggest that the inhibitory effect of UGN on NHE3 transport activity in proximal tubule is mediated by activation of both cGMP/PKG and cAMP/PKA signaling pathways which in turn leads to NHE3 phosphorylation and reduced NHE3 surface expression. Moreover, this study sheds light on mechanisms by which guanylin peptides are intricately involved in the maintenance of salt and water homeostasis.
Collapse
Affiliation(s)
- Lucília M A Lessa
- Department of Physiology and Biophysics, Biomedical Sciences Institute, University of São Paulo, São Paulo/SP, Brazil.
| | | | | | | | | | | | | | | |
Collapse
|
14
|
Adaramoye OA, Nwosu IO, Farombi EO. Sub-acute effect of N(G)-nitro-l-arginine methyl-ester (L-NAME) on biochemical indices in rats: Protective effects of Kolaviron and extract of Curcuma longa L. Pharmacognosy Res 2012; 4:127-33. [PMID: 22923949 PMCID: PMC3424838 DOI: 10.4103/0974-8490.99071] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 11/07/2011] [Accepted: 07/27/2012] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Kolaviron (KV) (biflavonoid from Garcinia kola) and extract of Curcuma longa (CL) are frequently used in folk medicine for treatment of hypertension. One of their mechanisms of action is to enhance antioxidant properties in animals. N(G)- nitro- l- arginine methyl- ester (L- NAME) is L- arginine analogue, which by binding to Nitric Oxide Synthase (NOS) may induce hypertension partly due to increase in tissues oxidative stress. OBJECTIVES To investigate the effect of L- NAME on some biochemical indices and the possible protective effect of KV or CL. MATERIALS AND METHODS Four groups consisting of 6 rats each were used. One group served as control, second group received L- NAME (40 mg/kg/day). Third and fourth groups were treated with KV and CL, respectively and also received L- NAME. KV and CL were given at a dose of 200 mg/kg/day. RESULTS L- NAME caused a significant (P <0.05) increase in the levels of serum urea, creatine kinase and alanine aminotransferase relative to controls. L- NAME treated rats had markedly decreased hepatic catalase (CAT), superoxide dismutase (SOD), glutathione- S- transferase (GST) and reduced glutathione (GSH) levels. Precisely, L- NAME decreased CAT, SOD, GST and GSH by 48, 52, 76 and 40%, respectively. L- NAME intoxication significantly decreased (P <0.05) renal GSH and SOD levels. Also, L- NAME caused a significant (P <0.05) induction of lipid peroxidation (LPO) in the animals. Administration of KV or CL with L- NAME caused significant (P <0.05) inhibition of LPO and augments tissue antioxidant indices. CONCLUSION These results confirm the adverse effect of L- NAME on biochemical indices and, the ability of kolaviron or Curcuma longa to ameliorate the alterations.
Collapse
Affiliation(s)
- Oluwatosin A. Adaramoye
- Department of Biochemistry, Drug Metabolism and Toxicology Research Laboratories, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | - Ifeanyi O. Nwosu
- Department of Biochemistry, Drug Metabolism and Toxicology Research Laboratories, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | - Ebenezer O. Farombi
- Department of Biochemistry, Drug Metabolism and Toxicology Research Laboratories, College of Medicine, University of Ibadan, Ibadan, Nigeria
| |
Collapse
|
15
|
Althaus M. Gasotransmitters: novel regulators of epithelial na(+) transport? Front Physiol 2012; 3:83. [PMID: 22509167 PMCID: PMC3321473 DOI: 10.3389/fphys.2012.00083] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 03/20/2012] [Indexed: 11/13/2022] Open
Abstract
The vectorial transport of Na(+) across epithelia is crucial for the maintenance of Na(+) and water homeostasis in organs such as the kidneys, lung, or intestine. Dysregulated Na(+) transport processes are associated with various human diseases such as hypertension, the salt-wasting syndrome pseudohypoaldosteronism type 1, pulmonary edema, cystic fibrosis, or intestinal disorders, which indicate that a precise regulation of epithelial Na(+) transport is essential. Novel regulatory signaling molecules are gasotransmitters. There are currently three known gasotransmitters: nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H(2)S). These molecules are endogenously produced in mammalian cells by specific enzymes and have been shown to regulate various physiological processes. There is a growing body of evidence which indicates that gasotransmitters may also regulate Na(+) transport across epithelia. This review will summarize the available data concerning NO, CO, and H(2)S dependent regulation of epithelial Na(+) transport processes and will discuss whether or not these mediators can be considered as true physiological regulators of epithelial Na(+) transport biology.
Collapse
Affiliation(s)
- Mike Althaus
- Institute of Animal Physiology, Justus Liebig University of Giessen Giessen, Germany
| |
Collapse
|
16
|
Garvin JL, Herrera M, Ortiz PA. Regulation of renal NaCl transport by nitric oxide, endothelin, and ATP: clinical implications. Annu Rev Physiol 2011; 73:359-76. [PMID: 20936940 DOI: 10.1146/annurev-physiol-012110-142247] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
NaCl absorption along the nephron is regulated not just by humoral factors but also by factors that do not circulate or act on the cells where they are produced. Generally, nitric oxide (NO) inhibits NaCl absorption along the nephron. However, the effects of NO in the proximal tubule are controversial and may be biphasic. Similarly, the effects of endothelin on proximal tubule transport are biphasic. In more distal segments, endothelin inhibits NaCl absorption and may be mediated by NO. Adenosine triphosphate (ATP) inhibits sodium bicarbonate absorption in the proximal tubule, NaCl absorption in thick ascending limbs via NO, and water reabsorption in collecting ducts. Defects in the effects of NO, endothelin, and ATP increase blood pressure, especially in a NaCl-sensitive manner. In diabetes, disruption of NO-induced inhibition of transport may contribute to increased blood pressure and renal damage. However, our understanding of how NO, endothelin, and ATP work, and of their role in pathology, is rudimentary at best.
Collapse
Affiliation(s)
- Jeffrey L Garvin
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan 48202, USA.
| | | | | |
Collapse
|
17
|
Nascimento NRF, Kemp BA, Howell NL, Gildea JJ, Santos CF, Harris TE, Carey RM. Role of SRC family kinase in extracellular renal cyclic guanosine 3',5'-monophosphate- and pressure-induced natriuresis. Hypertension 2011; 58:107-13. [PMID: 21482955 DOI: 10.1161/hypertensionaha.110.168708] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
cGMP functions as an extracellular (paracrine) messenger acting at the renal proximal tubule and is an important modulator of pressure-natriuresis (P-N). The signaling pathway activated by cGMP in the tubule cell basolateral membrane remains unknown. We hypothesized that renal interstitial microinfusion of cGMP (50 nmol/kg per minute) or P-N would be accompanied by increased renal protein levels of phospho-Src (Tyr 416) and that the natriuresis would be decreased by Src inhibition. Renal interstitial cGMP-induced natriuresis was blocked by Src inhibitor PP2 (2.0±0.4 versus 0.5±0.01 μEq/g per minute; P<0.001). The inactive analog of PP2, PP3, had no effect on cGMP-induced natriuresis. SU6656, another Src inhibitor, also inhibited cGMP-induced natriuresis (2.0±0.4 versus 1.02±0.01 μEq/g per minute; P<0.001). Renal interstitial cGMP infusion increased phospho-Src protein levels 5.6-fold at 15 minutes and 6.8-fold at 30 minutes compared with vehicle infusion but returned toward basal levels after 60 minutes. PP2 also blunted P-N (3.1±0.1 versus 1.1±0.3 μEq/g per minute; P<0.01) despite a similar increase in blood pressure. PP3 had no effect on P-N. Phospho-Src protein levels increased during P-N in vehicle- (1.8-fold) and PP3-treated (2.1-fold) groups compared with the sham-operated group. PP2 blocked the pressure-induced increase in renal phospho-Src protein levels. PP2 had no effect on renal hemodynamics but decreased both fractional excretion of Na(+) and lithium. Both extracellular cGMP and increased renal perfusion pressure increased renal phospho-Src protein levels and induced natriuresis in an Src-dependent manner, demonstrating that Src is an important downstream signaling molecule for extracellular cGMP-induced natriuresis.
Collapse
Affiliation(s)
- Nilberto R F Nascimento
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, VA 22908-1414, USA
| | | | | | | | | | | | | |
Collapse
|
18
|
Kohan DE, Rossi NF, Inscho EW, Pollock DM. Regulation of blood pressure and salt homeostasis by endothelin. Physiol Rev 2011; 91:1-77. [PMID: 21248162 DOI: 10.1152/physrev.00060.2009] [Citation(s) in RCA: 276] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Endothelin (ET) peptides and their receptors are intimately involved in the physiological control of systemic blood pressure and body Na homeostasis, exerting these effects through alterations in a host of circulating and local factors. Hormonal systems affected by ET include natriuretic peptides, aldosterone, catecholamines, and angiotensin. ET also directly regulates cardiac output, central and peripheral nervous system activity, renal Na and water excretion, systemic vascular resistance, and venous capacitance. ET regulation of these systems is often complex, sometimes involving opposing actions depending on which receptor isoform is activated, which cells are affected, and what other prevailing factors exist. A detailed understanding of this system is important; disordered regulation of the ET system is strongly associated with hypertension and dysregulated extracellular fluid volume homeostasis. In addition, ET receptor antagonists are being increasingly used for the treatment of a variety of diseases; while demonstrating benefit, these agents also have adverse effects on fluid retention that may substantially limit their clinical utility. This review provides a detailed analysis of how the ET system is involved in the control of blood pressure and Na homeostasis, focusing primarily on physiological regulation with some discussion of the role of the ET system in hypertension.
Collapse
Affiliation(s)
- Donald E Kohan
- Division of Nephrology, University of Utah Health Sciences Center, Salt Lake City, Utah 84132, USA.
| | | | | | | |
Collapse
|
19
|
Abstract
Loss of redox homeostasis and formation of excessive free radicals play an important role in the pathogenesis of kidney disease and hypertension. Free radicals such as reactive oxygen species (ROS) are necessary in physiologic processes. However, loss of redox homeostasis contributes to proinflammatory and profibrotic pathways in the kidney, which in turn lead to reduced vascular compliance and proteinuria. The kidney is susceptible to the influence of various extracellular and intracellular cues, including the renin-angiotensin-aldosterone system (RAAS), hyperglycemia, lipid peroxidation, inflammatory cytokines, and growth factors. Redox control of kidney function is a dynamic process with reversible pro- and anti-free radical processes. The imbalance of redox homeostasis within the kidney is integral in hypertension and the progression of kidney disease. An emerging paradigm exists for renal redox contribution to hypertension.
Collapse
Affiliation(s)
- Ravi Nistala
- University of Missouri-Columbia School of Medicine, Department of Internal Medicine, Columbia, Missouri 65212, USA.
| | | | | |
Collapse
|
20
|
Ahmed F, Kemp BA, Howell NL, Siragy HM, Carey RM. Extracellular renal guanosine cyclic 3'5'-monophosphate modulates nitric oxide and pressure-induced natriuresis. Hypertension 2007; 50:958-63. [PMID: 17846351 DOI: 10.1161/hypertensionaha.107.092973] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This study addresses the hypothesis that NO- and pressure-induced natriuresis are inhibited when guanosine cyclic 3',5'-monophosphate (cGMP) is prevented from being transported outside its renal synthesizing cells in vivo. Rats received a renal interstitial (RI) infusion of NO donor S-nitroso-N-acetylpenicillamine (SNAP) or SNAP+organic anion transporter inhibitor probenecid (PB) or SNAP+PB+cGMP. SNAP alone increased U(Na)V (P<0.05 at 1 hour and P<0.005 at 2 hours). In contrast, SNAP failed to increase U(Na)V when coinfused with PB, but cGMP coinfused with SNAP+probenecid restored the natriuretic response. SNAP alone increased RI cGMP (P<0.05) during the second experimental period. PB abolished the increase in RI cGMP in response to SNAP (P<0.01), but cGMP levels were restored by coinfusion with cGMP. PB also abolished SNAP-induced increases in fractional excretion of Na(+) (FE(Na)) and lithium (FE(Li)) (both P<0.01). PB also abolished the rise in RI cGMP and natriuresis induced by raising renal perfusion pressure (RPP) from 100 to 160 mm Hg in rats subjected to a standard pressure-natriuresis protocol and the natriuretic response was rescued by coinfusion with cGMP. RI administration of phosphodiesterase type V (PDE V) reduced both RIcGMP and U(Na)V in parallel (both P<0.01) without altering RIcAMP. The data demonstrate that export of cGMP from its renal synthesizing cells into the extracellular RI compartment is critical for the natriuretic action of NO donor SNAP or increased RPP and that RI cGMP controls basal Na(+) excretion. Extracellular cGMP modulates NO- and pressure-induced natriuresis.
Collapse
Affiliation(s)
- Farah Ahmed
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health Sciences Center, Charlottesville, USA
| | | | | | | | | |
Collapse
|
21
|
Kempson S, Thompson N, Pezzuto L, Glenn Bohlen H. Nitric oxide production by mouse renal tubules can be increased by a sodium-dependent mechanism. Nitric Oxide 2007; 17:33-43. [PMID: 17604190 PMCID: PMC2045156 DOI: 10.1016/j.niox.2007.05.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Revised: 05/15/2007] [Accepted: 05/20/2007] [Indexed: 11/29/2022]
Abstract
Renal tubules process large amounts of NaCl that other investigators indicate increases tubular generation of nitric oxide. We questioned whether medullary or superficial cortical tubules would have the greater increase in nitric oxide concentration, [NO], when stressed by sodium and if the sodium/calcium exchanger was involved. Sodium stress in proximal tubules is due to the large amount of sodium absorbed and medullary tubules exist in a hypertonic sodium environment. To sodium stress the tissue, mouse kidney slices were exposed to monensin to allow passive entry of sodium ions from isotonic media and in separate studies, 400 and 600 mOsm NaCl was used. [NO] was measured with microelectrodes. Monensin (10 microM) caused a sustained increase in medullary and cortical [NO] to approximately 180% of control and 400 mOsm NaCl caused a similar initial increase in [NO] that then subsided. 600 mOsm NaCl caused a more sustained increase in [NO] of >250% of control. L-NAME strongly attenuated the increased [NO] during sodium stress. The increase in [NO] during NaCl elevation was due to sodium ions because mannitol hyperosmolarity caused approximately 20% of the increase in [NO]. Entry of sodium during NaCl hyperosmolarity was through bumetanide sensitive channels because the drug suppressed increased [NO]. Blockade of the sodium/calcium ion exchanger strongly suppressed the increased [NO] during monensin, to increase sodium entry into cells, and the elevated NaCl concentration. The data support a sodium-NO linkage that increased NO signaling in proportion to sodium stress by cortical tubules and was highly dependent upon sodium-calcium exchange.
Collapse
Affiliation(s)
- Stephen Kempson
- Department of Cellular and Integrative Physiology, Indiana University Medical School, 635 Barnhill Drive, Indianapolis, IN 46202, USA
| | | | | | | |
Collapse
|
22
|
Boerrigter G, Costello-Boerrigter LC, Cataliotti A, Lapp H, Stasch JP, Burnett JC. Targeting Heme-Oxidized Soluble Guanylate Cyclase in Experimental Heart Failure. Hypertension 2007; 49:1128-33. [PMID: 17325237 DOI: 10.1161/hypertensionaha.106.083832] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Soluble guanylate cyclase is a heterodimeric enzyme with a prosthetic heme group that, on binding of its main ligand, NO, generates the second messenger cGMP. Unlike conventional nitrovasodilators, the novel direct NO- and heme-independent soluble guanylate cyclase activator BAY 58-2667 is devoid of non-cGMP actions, lacks tolerance development, and preferentially activates NO-insensitive heme-free or oxidized soluble guanylate cyclase. BAY 58-2667, therefore, represents a novel therapeutic advance in mediating vasodilation. To date, its cardiorenal actions in congestive heart failure (CHF) are undefined. We, therefore, hypothesized that BAY 58-2667 would have beneficial preload- and afterload-reducing actions in experimental severe CHF together with renal vasodilating properties. We assessed the cardiorenal actions of intravenous administration of 2 doses of BAY 58-2667 (0.1 and 0.3 μg/kg per minute, respectively) in a model of tachypacing-induced severe CHF. In CHF, BAY 58-2667 dose-dependently reduced mean arterial, right atrial, pulmonary artery, and pulmonary capillary wedge pressure (from baseline 19±1 to 12±2 mm Hg). Cardiac output (2.4±0.3 to 3.2±0.4 L/min) and renal blood flow increased. Glomerular filtration rate and sodium and water excretion were maintained. Consistent with cardiac unloading, atrial and B-type natriuretic peptide decreased. Plasma renin activity (
P
=0.31) and aldosterone remained unchanged (
P
=0.19). In summary, BAY 58-2667 in experimental CHF potently unloaded the heart, increased cardiac output and renal blood flow, and preserved glomerular filtration rate and sodium and water excretion without further neurohumoral activation. These beneficial properties make direct soluble guanylate cyclase stimulation with BAY 58-2667 a promising new therapeutic strategy for cardiovascular diseases, such as heart failure.
Collapse
Affiliation(s)
- Guido Boerrigter
- Cardiorenal Research Laboratory, Mayo Clinic and Foundation, Rochester, MN 55905, USA.
| | | | | | | | | | | |
Collapse
|
23
|
Poschet JF, Fazio JA, Timmins GS, Ornatowski W, Perkett E, Delgado M, Deretic V. Endosomal hyperacidification in cystic fibrosis is due to defective nitric oxide-cylic GMP signalling cascade. EMBO Rep 2006; 7:553-9. [PMID: 16612392 PMCID: PMC1479567 DOI: 10.1038/sj.embor.7400674] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2005] [Revised: 01/23/2006] [Accepted: 03/02/2006] [Indexed: 12/31/2022] Open
Abstract
Endosomal hyperacidification in cystic fibrosis (CF) respiratory epithelial cells is secondary to a loss of sodium transport control owing to a defective form of the CF transmembrane conductance regulator CFTR. Here, we show that endosomal hyperacidification can be corrected by activating the signalling cascade controlling sodium channels through cyclic GMP. Nitric oxide (NO) donors corrected the endosomal hyperacidification in CF cells. Stimulation of CF cells with guanylate cyclase agonists corrected the pH in endosomes. Exposure of CF cells to an inhibitor of cGMP-specific phosphodiesterase PDE5, Sildenafil, normalized the endosomal pH. Treatment with Sildenafil reduced secretion by CF cells of the proinflammatory chemokine interleukin 8 following stimulation with Pseudomonas aeruginosa products. Thus, the endosomal hyperacidification and excessive proinflammatory response in CF are in part due to deficiencies in NO- and cGMP-regulated processes and can be pharmacologically reversed using PDE5 inhibitors.
Collapse
Affiliation(s)
- Jens F Poschet
- Department of Molecular Genetics & Microbiology, University of New Mexico, Albuquerque, New Mexico, 87131, USA
| | - Joseph A Fazio
- Department of Molecular Genetics & Microbiology, University of New Mexico, Albuquerque, New Mexico, 87131, USA
| | - Graham S Timmins
- College of Pharmacy, Health Sciences Center, University of New Mexico, Albuquerque, New Mexico, 87131, USA
| | - Wojciech Ornatowski
- Department of Molecular Genetics & Microbiology, University of New Mexico, Albuquerque, New Mexico, 87131, USA
| | - Elizabeth Perkett
- Department of Pediatry, University of New Mexico, Albuquerque, New Mexico, 87131, USA
| | - Monica Delgado
- Department of Molecular Genetics & Microbiology, University of New Mexico, Albuquerque, New Mexico, 87131, USA
| | - Vojo Deretic
- Department of Molecular Genetics & Microbiology, University of New Mexico, Albuquerque, New Mexico, 87131, USA
- Department of Cell Biology & Physiology, School of Medicine, University of New Mexico, Albuquerque, New Mexico, 87131, USA
- Tel: +1 505 272 0291; Fax: +1 505 272 5309; E-mail:
| |
Collapse
|
24
|
Kim JS, Choi KC, Jeong MH, Kim SW, Oh YW, Lee JU. Increased expression of sodium transporters in rats chronically inhibited of nitric oxide synthesis. J Korean Med Sci 2006; 21:1-4. [PMID: 16479055 PMCID: PMC2733954 DOI: 10.3346/jkms.2006.21.1.1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The present study was done to determine whether endogenous nitric oxide (NO) plays a role in the regulation of sodium transporters in the kidney. Male Sprague-Dawley rats were treated with NG-nitro-L-arginine methyl ester (L-NAME, 100 mg/L drinking water) for 4 weeks. Control rats were supplied with tap water without drugs. Expression of Na, K-ATPase, type 3 Na/H exchanger (NHE3), Na/K/2Cl cotransporter (BSC1), and thiazide-sensitive Na/Cl cotransporter (TSC) proteins was determined in the kidney by Western blot analysis. Catalytic activity of Na,K-ATPase was also determined. The treatment with L-NAME significantly and steadily increased the systemic blood pressure. Total and fractional excretion of urinary sodium decreased significantly, while creatinine clearance remained unaltered. Neither plasma renin activity nor aldosterone concentration was significantly altered. The alpha1 subunit expression and the catalytic activity of Na, K-ATPase were increased in the kidney. The expression of NHE3, BSC1 and TSC was also increased significantly. These results suggest that endogenously-derived NO exerts a tonic inhibitory effect on the expression of sodium transporters, including Na, K-ATPase, NHE3, BSC1, and TSC, in the kidney.
Collapse
Affiliation(s)
- Joon Sik Kim
- Department of Physiology, Chonnam National University Medical School, Gwangju, Korea
| | | | | | | | | | | |
Collapse
|
25
|
Hakam AC, Hussain T. Angiotensin II AT2 receptors inhibit proximal tubular Na+-K+-ATPase activity via a NO/cGMP-dependent pathway. Am J Physiol Renal Physiol 2005; 290:F1430-6. [PMID: 16380464 DOI: 10.1152/ajprenal.00218.2005] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Angiotensin II AT2 receptors act as a functional antagonist for the AT1 receptors in various tissues. We previously reported that activation of the renal AT2 receptors promotes natriuresis and diuresis; however, the mechanism is not known. The present study was designed to investigate whether activation of AT2 receptors affects the activity of Na+-K+-ATPase (NKA), an active tubular sodium transporter, in the proximal tubules isolated from Sprague-Dawley rats. The AT2 receptor agonist CGP-42112 (10(-10)-10(-7) M) produced a dose-dependent inhibition of NKA activity (9-38%); the inhibition was attenuated by the presence of the AT2 receptor antagonist PD-123319 (1 microM), suggesting the involvement of the AT2 receptors. The AT1 receptor antagonist losartan (1 microM) did not affect the CGP-42112 (100 nM)-induced inhibition of NKA activity. The presence of guanylyl cyclase inhibitor ODQ (10 microM) and the nitric oxide (NO) synthase inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME; 100 microM) abolished the CGP-42112 (100 nM)-induced NKA inhibition. ANG II (100 nM), in the presence of losartan, significantly inhibited NKA activity; the inhibition was attenuated by PD-123319. CGP-42112 also, in a dose-dependent manner, stimulated NO production (approximately 0-230%) and cGMP accumulation (approximately 25-100%). The CGP-42112 (100 nM)-induced NO and cGMP increases were abolished by the AT2 receptor antagonist PD-123319, ODQ, and L-NAME. The data suggest that the activation of the AT2 receptor via stimulation of the NO/cGMP pathway causes inhibition of NKA activity in the proximal tubules. This phenomenon provides a plausible mechanism responsible for the AT2 receptor-mediated natriuresis-diuresis in rodents.
Collapse
Affiliation(s)
- Amer C Hakam
- Dept. of Pharmacological and Pharmaceutical Sciences, Science and Research Bldg. 2, Univ. of Houston, 4800 Calhoun, Houston, TX 77204-5037, USA
| | | |
Collapse
|
26
|
Massaro RC, Lee LW, Patel AB, Wu DS, Yu MJ, Scott BN, Schooley DA, Schegg KM, Beyenbach KW. The mechanism of action of the antidiuretic peptide Tenmo ADFa in Malpighian tubules of Aedes aegypti. ACTA ACUST UNITED AC 2004; 207:2877-88. [PMID: 15235016 DOI: 10.1242/jeb.01102] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The mechanism of action of Tenebrio molitor antidiuretic factor 'a' (Tenmo ADFa) was explored in isolated Malpighian tubules of Aedes aegypti. In the Ramsay assay of fluid secretion, Tenmo ADFa (10(-9) mol l(-1)) significantly inhibited the rate of fluid secretion from 0.94 nl min(-1) to 0.44 nl min(-1) without significant effects on the concentrations of Na+, K+ and Cl- in secreted fluid. In isolated perfused tubules, Tenmo ADFa had no effect on the transepithelial voltage (Vt) and resistance (Rt). In principal cells of the tubule, Tenmo ADFa had no effect on the basolateral membrane voltage (Vbl) and the input resistance of principal cells (Rpc). Tenmo ADFa significantly increased the intracellular concentration of cyclic guanosine monophosphate (cGMP) from 2.9 micromol l(-1) (control) to 7.4 micromol l(-1). A peritubular [cGMP] of 20 micromol l(-1) duplicated the antidiuretic effects of Tenmo ADFa without inducing electrophysiological effects. In contrast, 500 micromol l(-1) cGMP significantly depolarized V(bl), hyperpolarized Vt, and reduced Rt and Rpc, without increasing antidiuretic potency beyond that of 20 micromol l(-1) cGMP. A plot of peritubular cGMP concentration vs Vbl revealed a steep dose-response between 300 micromol l(-1) and 700 micromol l(-1) with an EC50 of 468 micromol l(-1). These observations suggest a receptor- and cGMP-mediated mechanism of action of Tenmo ADFa. Tenmo ADFa and physiological concentrations of cGMP (< 20 micromol l(-1)) reduce the rate of isosmotic fluid secretion by quenching electroneutral transport systems. The inhibition reveals that as much as 50% of the normal secretory solute and water flux can stem from electrically silent mechanisms in this highly electrogenic epithelium.
Collapse
Affiliation(s)
- Richard C Massaro
- Department of Biomedical Sciences, VRT 8004, Cornell University, Ithaca, NY 14853, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Clark IA, Alleva LM, Mills AC, Cowden WB. Pathogenesis of malaria and clinically similar conditions. Clin Microbiol Rev 2004; 17:509-39, table of contents. [PMID: 15258091 PMCID: PMC452556 DOI: 10.1128/cmr.17.3.509-539.2004] [Citation(s) in RCA: 136] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
There is now wide acceptance of the concept that the similarity between many acute infectious diseases, be they viral, bacterial, or parasitic in origin, is caused by the overproduction of inflammatory cytokines initiated when the organism interacts with the innate immune system. This is also true of certain noninfectious states, such as the tissue injury syndromes. This review discusses the historical origins of these ideas, which began with tumor necrosis factor (TNF) and spread from their origins in malaria research to other fields. As well the more established proinflammatory mediators, such as TNF, interleukin-1, and lymphotoxin, the roles of nitric oxide and carbon monoxide, which are chiefly inhibitory, are discussed. The established and potential roles of two more recently recognized contributors, overactivity of the enzyme poly(ADP-ribose) polymerase 1 (PARP-1) and the escape of high-mobility-group box 1 (HMGB1) protein from its normal location into the circulation, are also put in context. The pathogenesis of the disease caused by falciparum malaria is then considered in the light of what has been learned about the roles of these mediators in these other diseases, as well as in malaria itself.
Collapse
Affiliation(s)
- Ian A Clark
- School of Biochemistry and Molecular Biology, Australian National University, Canberra, ACT 0200, Australia.
| | | | | | | |
Collapse
|
28
|
Nakamura K, Hirano J, Kubokawa M. Regulation of an inwardly rectifying K+ channel by nitric oxide in cultured human proximal tubule cells. Am J Physiol Renal Physiol 2004; 287:F411-7. [PMID: 15140759 DOI: 10.1152/ajprenal.00014.2004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated the effects of nitric oxide (NO) on activity of the inwardly rectifying K(+) channel in cultured human proximal tubule cells, using the cell-attached mode of the patch-clamp technique. An inhibitor of NO synthases, N(omega)-nitro-L-arginine methyl ester (L-NAME; 100 microM), reduced channel activity, which was restored by an NO donor, sodium nitroprusside (SNP; 10 microM) or 8-bromo-cGMP (8-BrcGMP; 100 microM). However, SNP failed to activate the channel in the presence of an inhibitor of soluble guanylate cyclase, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (10 microM). Similarly, the SNP effect was abolished by a protein kinase G (PKG)-specific inhibitor, KT-5823 (1 microM), but not by a protein kinase A-specific inhibitor, KT-5720 (500 nM). Another NO donor, S-nitroso-N-acetyl-D,L-penicillamine (10 microM), mimicked the SNP-induced channel activation. In contrast to the stimulatory effect of SNP at a low dose (10 microM), a higher dose of SNP (1 mM) reduced channel activity, which was not restored by 8-BrcGMP. Recordings of membrane potential with the slow whole cell configuration demonstrated that l-NAME (100 microM) and the high dose of SNP (1 mM) depolarized the cell by 10.1 +/- 2.6 and 9.2 +/- 1.0 mV, respectively, whereas the low dose of SNP (10 microM) hyperpolarized it by 7.1 +/- 0.7 mV. These results suggested that the endogenous NO would contribute to the maintenance of basal activity of this K(+) channel and hence the potential formation via a cGMP/PKG-dependent mechanism, whereas a high dose of NO impaired channel activity independent of cGMP/PKG-mediated processes.
Collapse
Affiliation(s)
- Kazuyoshi Nakamura
- Department of Physiology II, Iwate Medical University School of Medicine, Morioka, 020-8505 Japan
| | | | | |
Collapse
|
29
|
Jin XH, McGrath HE, Gildea JJ, Siragy HM, Felder RA, Carey RM. Renal interstitial guanosine cyclic 3', 5'-monophosphate mediates pressure-natriuresis via protein kinase G. Hypertension 2004; 43:1133-9. [PMID: 15007031 DOI: 10.1161/01.hyp.0000123574.60586.7d] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Pressure-natriuresis is the physiological protective mechanism whereby elevation of blood pressure induces a rapid increase in renal sodium (Na+) excretion. Pressure-natriuresis abnormalities are common to all forms of hypertension. We tested the hypothesis that pressure-natriuresis is mediated by renal interstitial (RI) cGMP and protein kinase G (PKG). We used anesthetized, uninephrectomized Sprague-Dawley rats and a standard pressure-natriuresis model in which bilateral adrenalectomy and renal denervation was done on rats. Renal perfusion pressure (RPP) was adjusted by manipulating clamps above and below the renal artery, and RI cGMP was quantified by microdialysis. RI cGMP increased from 3.1+/-0.5 to 5.5+/-0.4 fmol/min (P<0.05) when RPP was raised from 100 to 140 mm Hg. This increase in RI cGMP was eliminated by RI infusion of soluble guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,2-alpha]quinoxalin-1-one (ODQ). Raising RPP from 100 to 140 mm Hg increased urinary sodium excretion from 0.2+/-0.1 to 0.8+/-0.1 micromol/min, fractional sodium excretion from 0.2+/-0.1% to 0.8+/-0.1%, and fractional lithium excretion from 20.1+/-3.0% to 62.7+/-3.7% (all P<0.05). These responses were eliminated by RI infusion of nitric oxide synthase inhibitor N-nitro-l-arginine methyl ester, ODQ, and PKG inhibitors Rp-8-pCPT-cGMP and Rp-8-Br-cGMP. Increasing RPP from 100 to 140 mm Hg decreased fractional proximal sodium reabsorption without influencing fractional distal Na+ reabsorption or glomerular filtration rate. In conclusion, pressure-natriuresis is mediated by RI cGMP and a PKG signaling pathway in target renal proximal tubule cells.
Collapse
Affiliation(s)
- Xiao-Hong Jin
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, VA 22908-1414, USA
| | | | | | | | | | | |
Collapse
|
30
|
Notenboom S, Miller DS, Smits P, Russel FGM, Masereeuw R. Involvement of guanylyl cyclase and cGMP in the regulation of Mrp2-mediated transport in the proximal tubule. Am J Physiol Renal Physiol 2004; 287:F33-8. [PMID: 14970002 DOI: 10.1152/ajprenal.00443.2003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In killifish renal proximal tubules, endothelin-1 (ET-1), acting through a basolateral ET(B) receptor, nitric oxide synthase (NOS), and PKC, decreases cell-to-lumen organic anion transport mediated by the multidrug resistance protein isoform 2 (Mrp2). In the present study, we examined the roles of guanylyl cyclase and cGMP in ET signaling to Mrp2. Using confocal microscopy and quantitative image analysis to measure Mrp2-mediated transport of the fluorescent drug fluorescein methotrexate (FL-MTX), we found that oxadiazole quinoxalin (ODQ), an inhibitor of NO-sensitive guanylyl cyclase, blocked ET-1 signaling. ODQ was also effective when signaling was initiated by nephrotoxicants (gentamicin, amikacin, diatrizoate, HgCl(2), and CdCl(2)), which appear to stimulate ET release from the tubules themselves. ODQ blocked the effects of the NO donor sodium nitroprusside but not of the phorbol ester that activates PKC. Exposing tubules to 8-bromo-cGMP (8-BrcGMP), a cell-permeable cGMP analog, decreased luminal FL-MTX accumulation. This effect was abolished by bisindoylmaleimide (BIM), a PKC inhibitor, but not by N(G)-methyl-l-arginine, a NOS inhibitor. Together, these data indicate that ET regulation of Mrp2 involves activation of guanylyl cyclase and generation of cGMP. Signaling by cGMP follows NO release and precedes PKC activation.
Collapse
Affiliation(s)
- Sylvia Notenboom
- Department of Pharmacology and Toxicology, University Medical Center Nijmegen, 6500 HB Nijmegen, The Netherlands
| | | | | | | | | |
Collapse
|
31
|
Zimpelmann J, Li N, Burns KD. Nitric oxide inhibits superoxide-stimulated urea permeability in the rat inner medullary collecting duct. Am J Physiol Renal Physiol 2003; 285:F1160-7. [PMID: 12965888 DOI: 10.1152/ajprenal.00077.2003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The inner medullary collecting duct (IMCD) contains relatively high nitric oxide (NO) synthetic capacity, but the effect of NO on IMCD transport remains unclear. We determined the effect of NO on basal and vasopressin (AVP)-stimulated urea (Purea) and water (Pf) permeabilities in isolated, perfused rat IMCD. The NO donor S-nitroso-N-acetylpenicillamine (SNAP) increased cGMP production in IMCD, but neither SNAP (10(-4) M) nor 8-BrcGMP (10(-4) M), the cell-permeable analog of cGMP, affected basal or AVP-stimulated Purea. The free radical superoxide is produced by oxidases in the kidney and can interact with NO. To determine the effect of superoxide generation on transport, IMCDs were incubated with diethyldithiocarbamate (DETC; 10(-3) M), the inhibitor of superoxide dismutase (SOD). DETC significantly increased basal and AVP-stimulated Purea (control: 28.7 +/- 4.5 vs. DETC: 40.9 +/- 6.2 x 10(-5) cm/s; P < 0.001; n = 9). Preincubation of IMCD with SNAP or the SOD mimetic tempol completely inhibited DETC-stimulated Purea. DETC caused a significant increase in superoxide generation by IMCD, and this was blocked by SNAP. Incubation of IMCD with the NO synthase (NOS) substrate l-arginine blocked the stimulatory effect of DETC on Purea, and this was reversed by the neuronal NOS inhibitor 7-nitroindazole. In contrast, neither basal nor AVP-stimulated Pf was affected by NO donors or DETC. In summary, exogenous or endogenously produced NO does not affect basal urea transport in the IMCD but inhibits superoxide-stimulated Purea. In the inner medulla, superoxide generation by local oxidases may stimulate urea transport, and the role of endogenous NO may be to dampen this effect by decreasing superoxide levels.
Collapse
Affiliation(s)
- Joseph Zimpelmann
- Division of Nephrology, The Ottawa Hospital and University of Ottawa, 1967 Riverside Drive, Ottawa, Ontario, Canada K1H 7W9
| | | | | |
Collapse
|
32
|
Abstract
Signaling cascades initiated by nitric oxide (NO) and natriuretic peptides (NPs) play an important role in the maintenance of cardiovascular homeostasis. It is currently accepted that many effects of these endogenous signaling molecules are mediated via stimulation of guanylyl cyclases and intracellular production of the second messenger cGMP. Indeed, cGMP-elevating drugs like glyceryl trinitrate have been used for more than 100 years to treat cardiovascular diseases. However, the molecular mechanisms of NO/NP signaling downstream of cGMP are not completely understood. Recent in vitro and in vivo evidence identifies cGMP-dependent protein kinases (cGKs) as major mediators of cGMP signaling in the cardiovascular system. In particular, the analysis of conventional and conditional knockout mice indicates that cGKs are critically involved in regulating vascular remodeling and thrombosis. Thus, cGKs may represent novel drug targets for the treatment of human cardiovascular disorders.
Collapse
Affiliation(s)
- Robert Feil
- Institut für Pharmakologie und Toxikologie, Technische Universität, Biedersteiner Str. 29, D-80802 München, Germany
| | | | | | | | | |
Collapse
|
33
|
Graebe M, Brond L, Christensen S, Nielsen S, Olsen NV, Jonassen TEN. Chronic nitric oxide synthase inhibition exacerbates renal dysfunction in cirrhotic rats. Am J Physiol Renal Physiol 2003; 286:F288-97. [PMID: 14583432 DOI: 10.1152/ajprenal.00089.2003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The present study investigated sodium balance and renal tubular function in cirrhotic rats with chronic blockade of the nitric oxide (NO) system. Rats were treated with the nonselective NO synthase inhibitor NG-nitro-l-arginine methyl ester (l-NAME) starting on the day of common bile duct ligation (CBL). Three weeks of daily sodium balance studies showed that CBL rats developed sodium retention compared with sham-operated rats and that l-NAME treatment dose dependently deteriorated cumulative sodium balance by reducing urinary sodium excretion. Five weeks after CBL, renal clearance studies were performed, followed by Western blotting of the electroneutral type 3 sodium/proton exchanger (NHE3) and the Na-K-ATPase present in proximal tubules. Untreated CBL rats showed a decreased proximal reabsorption with a concomitant reduction of NHE3 and Na-K-ATPase levels, indicating that tubular segments distal to the proximal tubules were responsible for the increased sodium reabsorption. l-NAME-treated CBL rats showed an increased proximal reabsorption measured by the lithium clearance method and showed a marked increase in NHE3 and Na-K-ATPase protein levels. Our results show that chronic l-NAME treatment exacerbates the sodium retention found in CBL rats by a significant increase in proximal tubular reabsorption.
Collapse
Affiliation(s)
- Martin Graebe
- Department of Pharmacology, University of Copenhagen, DK-2200 Copenhagen N, Denmark.
| | | | | | | | | | | |
Collapse
|
34
|
He H, Podymow T, Zimpelmann J, Burns KD. NO inhibits Na+-K+-2Cl- cotransport via a cytochrome P-450-dependent pathway in renal epithelial cells (MMDD1). Am J Physiol Renal Physiol 2003; 284:F1235-44. [PMID: 12582005 DOI: 10.1152/ajprenal.00192.2002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nitric oxide (NO) exerts direct effects on nephron transport. We determined the effect of NO on Na(+)-K(+)-2Cl(-) cotransport in a cell line (MMDD1) with properties of macula densa. Na(+)-K(+)-2Cl(-) cotransport was measured as bumetanide-sensitive (86)Rb(+) uptake in the presence of ouabain. MMDD1 cells expressed mRNA for the neuronal isoform of nitric oxide synthase, as well as NKCC1 and NKCC2(B) isoforms of the Na(+)-K(+)-2Cl(-) cotransporter. Preincubation of cells with the NO donors sodium nitroprusside (SNP) or S-nitroso-N-acetylpenicillamine (SNAP) caused concentration-dependent inhibition of Na(+)-K(+)-2Cl(-) cotransport. Both apical and basolateral Na(+)-K(+)-2Cl(-) cotransport was inhibited by NO donors. SNP or SNAP had no significant effect on cellular levels of cGMP, cAMP, cytosolic calcium, or phosphorylation of ERK1 and ERK2. In contrast, the inhibitors of cytochrome P-450, 1-aminobenzotriazole (ABT; 10(-3) M) or ketoconazole (1.5 x 10(-5) M), completely reversed the inhibitory effect of SNAP on apical or basolateral Na(+)-K(+)-2Cl(-) cotransport [apical: control 1.18 +/- 0.15 vs. SNAP (10(-4) M) 0.41 +/- 0.05 pmol x mg(-1) x 5 min(-1); P < 0.001; SNAP (10(-4) M) + ABT 1.32 +/- 0.10 pmol x mg(-1) x 5 min(-1); P = not significant vs. control; n = 5]. The cytochrome P-450 epoxyeicosatrienoic acid (EET) metabolite 14,15-EET (5 x 10(-7) M) inhibited both apical and basolateral cotransport, whereas 8,9-EET and 11,12-EET had no significant effect. Although 20-hydroxyeicosatetraenoic acid inhibited apical cotransport, the inhibitor of omega-hydroxylase activity HET0016 did not reverse SNAP-mediated inhibition of apical cotransport. These data indicate that NO inhibits apical and basolateral Na(+)-K(+)-2Cl(-) cotransport in MMDD1 cells. The results suggest that the inhibitory pathway is independent of cGMP and might involve stimulation of a cytochrome P-450-dependent pathway.
Collapse
Affiliation(s)
- Hao He
- Department of Medicine, Ottawa Hospital, and the Kidney Research Centre, Ottawa Health Research Institute, University of Ottawa, Ottawa, Ontario, Canada K1H 8L6
| | | | | | | |
Collapse
|
35
|
Clark IA, Awburn MM, Whitten RO, Harper CG, Liomba NG, Molyneux ME, Taylor TE. Tissue distribution of migration inhibitory factor and inducible nitric oxide synthase in falciparum malaria and sepsis in African children. Malar J 2003; 2:6. [PMID: 12716455 PMCID: PMC154094 DOI: 10.1186/1475-2875-2-6] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2003] [Accepted: 04/08/2003] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND The inflammatory nature of falciparum malaria has been acknowledged since increased circulating levels of tumour necrosis factor (TNF) were first measured, but precisely where the mediators downstream from this prototype inflammatory mediator are generated has not been investigated. Here we report on the cellular distribution, by immunohistochemistry, of migration inhibitory factor (MIF) and inducible nitric oxide synthase (iNOS) in this disease, and in sepsis. METHODS We stained for MIF and iNOS in tissues collected during 44 paediatric autopsies in Blantyre, Malawi. These comprised 42 acutely ill comatose patients, 32 of whom were diagnosed clinically as cerebral malaria and the other 10 as non-malarial diseases. Another 2 were non-malarial, non-comatose deaths. Other control tissues were from Australian adults. RESULTS Of the 32 clinically diagnosed cerebral malaria cases, 11 had negligible histological change in the brain, and no or scanty intravascular sequestration of parasitised erythrocytes, another 7 had no histological changes in the brain, but sequestered parasitised erythrocytes were present (usually dense), and the remaining 14 brains showed micro-haemorrhages and intravascular mononuclear cell accumulations, plus sequestered parasitised erythrocytes. The vascular walls of the latter group stained most strongly for iNOS. Vascular wall iNOS staining was usually of low intensity in the second group (7 brains) and was virtually absent from the cerebral vascular walls of 8 of the 10 comatose patients without malaria, and also from control brains. The chest wall was chosen as a typical non-cerebral site encompassing a range of tissues of interest. Here pronounced iNOS staining in vascular wall and skeletal muscle was present in some 50% of the children in all groups, including septic meningitis, irrespective of the degree of staining in cerebral vascular walls. Parasites or malarial pigment were rare to absent in all chest wall sections. While MIF was common in chest wall vessels, usually in association with iNOS, it was absent in brain vessels. CONCLUSIONS These results agree with the view that clinically diagnosed cerebral malaria in African children is a collection of overlapping syndromes acting through different organ systems, with several mechanisms, not necessarily associated with cerebral vascular inflammation and damage, combining to cause death.
Collapse
Affiliation(s)
- Ian A Clark
- Dept of Biochemistry, Australian National University, Canberra, Australia
| | - Melissa M Awburn
- Dept of Biochemistry, Australian National University, Canberra, Australia
| | | | | | - N George Liomba
- Dept of Histopathology, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Malcolm E Molyneux
- Wellcome Trust Laboratories and Malaria Project, College of Medicine, University of Malawi
- School of Tropical Medicine, University of Liverpool, UK
| | - Terrie E Taylor
- School of Tropical Medicine, University of Liverpool, UK
- Michigan State University, E. Lansing MI, USA
| |
Collapse
|
36
|
Ikari A, Nakajima K, Taki S, Suketa Y. Up-regulation of Na+-dependent Mg2+ transport by nitric oxide and cyclic GMP pathway in renal epithelial cells. Eur J Pharmacol 2002; 451:133-9. [PMID: 12231382 DOI: 10.1016/s0014-2999(02)02272-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A putative, Na(+)-dependent Mg(2+) transport pathway controls the intracellular free Mg(2+) concentration ([Mg(2+)](i)) in various mammalian cells. The characteristics of this Mg(2+) transport pathway have not been clarified. Herein, we examined the regulatory mechanism of Na(+)-dependent Mg(2+) efflux in renal epithelial NRK-52E cells. Mg(2+) removal from the extracellular bathing solution induced an Na(+)-dependent [Mg(2+)](i) decrease in Mg(2+) (5 mM)-loaded cells but not in control cells. Amiloride inhibited the [Mg(2+)](i) decrease in a dose-dependent manner (IC(50) = 3 microM). Similarly, atomic absorption spectrophotometry showed that Mg(2+) removal decreased intracellular Mg(2+) content, while it increased Na(+) content. Calphostin C (1 microM), a protein kinase C inhibitor, and genistein, a tyrosine kinase inhibitor (10 microM), blocked the [Mg(2+)](i) decrease. The [Mg(2+)](i) decrease was accompanied by an increase in intracellular nitric oxide (NO) and cyclic GMP contents. (E)-4-methyl-2-[(E)-hydoxyimino]-5-nitro-6-methoxy-3-hexenamide (0.1 mM), an NO donor, and 8-bromo-cyclic GMP (0.1 mM), a membrane-permeable cyclic GMP analogue, accelerated the [Mg(2+)](i) decrease. In contrast, N(G)-monomethyl-L-arginine (L-NMMA, 0.1 mM), an NO competitive inhibitor, and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline-1-one (ODQ, 10 microM), an NO-sensitive guanylate cyclase inhibitor, significantly blocked the [Mg(2+)](i) decrease. These results indicate that a decrease in extracellular Mg(2+) concentration induces the production of NO and cyclic GMP, which leads to the up-regulation of Na(+)-dependent Mg(2+) efflux.
Collapse
Affiliation(s)
- Akira Ikari
- Department of Environmental Biochemistry and Toxicology, University of Shizuoka School of Pharmaceutical Sciences, 52-1 Yada, Shizuoka City, Shizuoka 422-8526, Japan.
| | | | | | | |
Collapse
|
37
|
Gill RK, Saksena S, Syed IA, Tyagi S, Alrefai WA, Malakooti J, Ramaswamy K, Dudeja PK. Regulation of NHE3 by nitric oxide in Caco-2 cells. Am J Physiol Gastrointest Liver Physiol 2002; 283:G747-56. [PMID: 12181191 DOI: 10.1152/ajpgi.00294.2001] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The effect of nitric oxide (NO) on Na+/H+ exchange (NHE) activity was investigated utilizing Caco-2 cells as an experimental model. Incubation of Caco-2 cells with 10(-3) M S-nitroso-N-acetylpenicillamine (SNAP), a conventional donor of NO, for 20 min resulted in a approximately 45% dose-dependent decrease in NHE activity, as determined by assay of ethylisopropylamiloride-sensitive 22Na uptake. A similar decrease in NHE activity was observed utilizing another NO-specific donor, sodium nitroprusside. SNAP-mediated inhibition of NHE activity was not secondary to a loss of cell viability. NHE3 activity was significantly reduced by SNAP (P < 0.05), whereas NHE2 activity was essentially unaltered. The effects of SNAP were mediated by the cGMP-dependent signal transduction pathway as follows: 1) LY-83583 and 1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one (ODQ), specific inhibitors of soluble guanylate cyclase, blocked the inhibitory effect of SNAP on NHE; 2) 8-bromo-cGMP mimicked the effects of SNAP on NHE activity; 3) the SNAP-induced decrease in NHE activity was counteracted by a specific protein kinase G inhibitor, KT-5823 (1 microM); 4) chelerythrine chloride (2 microM) or calphostin C (200 nM), specific protein kinase C inhibitors, did not affect inhibition of NHE activity by SNAP; 5) there was no cross activation by the protein kinase A-dependent pathway, as the inhibitory effects of SNAP were not blocked by Rp-cAMPS (25 microM), a specific protein kinase A inhibitor. These data provide novel evidence that NO inhibits NHE3 activity via activation of soluble guanylate cyclase, resulting in an increase in intracellular cGMP levels and activation of protein kinase G.
Collapse
Affiliation(s)
- Ravinder K Gill
- Section of Digestive and Liver Diseases, Department of Medicine, University of Illinois at Chicago and West Side Veterans Affairs Medical Center, Chicago, Illinois 60612, USA
| | | | | | | | | | | | | | | |
Collapse
|
38
|
Saksena S, Gill RK, Syed IA, Tyagi S, Alrefai WA, Ramaswamy K, Dudeja PK. Modulation of Cl-/OH- exchange activity in Caco-2 cells by nitric oxide. Am J Physiol Gastrointest Liver Physiol 2002; 283:G626-33. [PMID: 12181176 DOI: 10.1152/ajpgi.00395.2001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The present studies were undertaken to determine the direct effects of nitric oxide (NO) released from an exogenous donor, S-nitroso-N-acetyl pencillamine (SNAP) on Cl-/OH- exchange activity in human Caco-2 cells. Our results demonstrate that NO inhibits Cl-/OH- exchange activity in Caco-2 cells via cGMP-dependent protein kinases G (PKG) and C (PKC) signal-transduction pathways. Our data in support of this conclusion can be outlined as follows: 1) incubation of Caco-2 cells with SNAP (500 microM) for 30 min resulted in approximately 50% inhibition of DIDS-sensitive 36Cl uptake; 2) soluble guanylate cyclase inhibitors Ly-83583 and (1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one significantly blocked the inhibition of Cl-/OH- exchange activity by SNAP; 3) addition of 8-bromo-cGMP (8-BrcGMP) mimicked the effects of SNAP; 4) specific PKG inhibitor KT-5823 significantly inhibited the decrease in Cl-/OH- exchange activity in response to either SNAP or 8-BrcGMP; 5) Cl-/OH-exchange activity in Caco-2 cells in response to SNAP was not altered in the presence of protein kinase A (PKA) inhibitor (Rp-cAMPS), demonstrating that the PKA pathway was not involved; 6) the effect of NO on Cl-/OH- exchange activity was mediated by PKC, because each of the two PKC inhibitors chelerythrine chloride and calphostin C blocked the SNAP-mediated inhibition of Cl-/OH- exchange activity; 7) SO/OH- exchange in Caco-2 cells was unaffected by SNAP. Our results suggest that NO-induced inhibition of Cl-/OH- exchange may play an important role in the pathophysiology of diarrhea associated with inflammatory bowel diseases.
Collapse
Affiliation(s)
- Seema Saksena
- Section of Digestive and Liver Diseases, Department of Medicine, University of Illinois at Chicago and Chicago Veteran's Affairs System: West Side Division, Chicago, Illinois 60612, USA
| | | | | | | | | | | | | |
Collapse
|
39
|
Baines A, Ho P. Glucose stimulates O2 consumption, NOS, and Na/H exchange in diabetic rat proximal tubules. Am J Physiol Renal Physiol 2002; 283:F286-93. [PMID: 12110512 DOI: 10.1152/ajprenal.00330.2001] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Endothelial nitric oxide synthase (NOS) and neuronal NOS protein increased in proximal tubules of acidotic diabetic rats 3-5 wk after streptozotocin injection. NOS activity (citrulline production) was similar in nondiabetic and diabetic tubules incubated with low glucose (5 mM glucose + 20 mM mannitol); but after 30 min with high glucose (25 mM), Ca-sensitive citrulline production had increased 23% in diabetic tubules. Glucose concentration did not influence citrulline production in nondiabetic tubules. High glucose increased carboxy-2-phenyl-4,4,5,5,-tetramethylimidazoline 1-oxyl-3-oxide (cpt10)-scavenged NO sevenfold in a suspension of diabetic tubules but did not alter NO in nondiabetic tubules. Diabetes increased ouabain-sensitive 86Rb uptake (141 +/- 9 vs. 122 +/- 6 nmol x min(-1) x mg(-1)) and oligomycin-sensitive O2 consumption (QO2; 16.0 +/- 1.7 vs. 11.3 +/- 0.7 nmol x min(-1) x mg(-1)). Ethylisopropyl amiloride-inhibitable QO2 (6.5 +/- 0.6 vs. 2.4 +/- 0.3 nmol x min(-1) x mg(-1)) accounted for increased oligomycin-sensitive QO2 in diabetic tubules. N(G)-monomethyl-L-arginine methyl ester (L-NAME) inhibited most of the increase in 86Rb uptake and QO2 in diabetic tubules. L-NAME had little effect on nondiabetic tubules. Inhibition of QO2 by ethylisopropyl amiloride and L-NAME was only 5-8% additive. Uncontrolled diabetes for 3-5 wk increases NOS protein in proximal tubules and makes NOS activity sensitive to glucose concentration. Under these conditions, NO stimulates Na-K-ATPase and QO2 in proximal tubules.
Collapse
Affiliation(s)
- Andrew Baines
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada M5G 1L5.
| | | |
Collapse
|
40
|
Abstract
Nitric oxide (NO) plays an important role in various physiological processes in the kidney. In vivo experiments first suggested that the natriuretic and diuretic effects caused by NO may be due to decreased NaCl and fluid absorption by the nephron. In the last 10 years, several reports have directly demonstrated a role for NO in modulating transport in different tubule segments. The effects of NO on proximal tubule transport are still controversial. Both stimulation and inhibition of net fluid and bicarbonate have been reported in this segment, whereas only inhibitory effects of NO have been found in Na/H exchanger and Na/K-ATPase activity. The effects of NO in the thick ascending limb are more homogeneous than in the proximal tubule. In this segment, NO decreases net Cl and bicarbonate absorption. A direct inhibitory effect of NO on the Na-K-2Cl cotransporter and the Na/H exchanger has been reported, while NO was found to stimulate apical K channels in this segment. In the collecting duct, NO inhibits Na absorption and vasopressin-stimulated osmotic water permeability. An inhibitory effect of NO on H-ATPase has also been reported in intercalated cells of the collecting duct. Overall, the reported effects of NO in the different nephron segments mostly agree with the natriuretic and diuretic effects observed in vivo. However, the net effect of NO on transport is still controversial in some segments, and in cases like the distal tubule, it has not been studied.
Collapse
Affiliation(s)
- Pablo A Ortiz
- Division of Hypertension and Vascular Research, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan 48202, USA
| | | |
Collapse
|
41
|
Escalante BA, McGiff JC, Oyekan AO. Role of cytochrome P-450 arachidonate metabolites in endothelin signaling in rat proximal tubule. Am J Physiol Renal Physiol 2002; 282:F144-50. [PMID: 11739122 DOI: 10.1152/ajprenal.0064.2001] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We examined the rat proximal tubule (PT) response to endothelin-1 (ET-1) in terms of 20-hydroxyeicosatetraenoic acid (HETE) dependency. Arachidonic acid (AA) (1 microM) decreased ouabain-sensitive (86)Rb uptake from 2.1 +/- 0.1 to 0.3 +/- 0.08 ng Rb. 10 microg protein(-1). 2 min(-1) (P < 0.05); 20-HETE (1 microM) had similar effects. Dibromododecenoic acid (DBDD) (2 microM), an inhibitor of omega-hydroxylase, abolished the inhibitory action of AA on (86)Rb uptake whereas the PT response to 20-HETE was unaffected. ET-1 at 0.1, 1, 10, and 100 nM reduced (86)Rb uptake from 2.8 +/- 0.3 in control PTs to 2.4 +/- 0.2, 1.7 +/- 0.1, 0.67 +/- 0.08, and 0.1 +/- 0.03 ng Rb. 10 microg protein(-1). 2 min(-1), respectively. DBDD (2 microM) abolished the inhibitory effect of ET-1 on (86)Rb uptake as did BMS182874 (1 microM), an ET(A)-selective receptor antagonist. ET-1 (100 nM) significantly increased PT 20-HETE release by approximately 50%, an effect prevented by DBDD. N(omega)-nitro-L-arginine-methyl ester (L-NAME), given for 4 days to inhibit nitric oxide synthase (NOS), increased arterial pressure from 92 +/- 12 to 140 +/- 8 mmHg and increased endogenous release of 20-HETE from isolated PTs (measured by gas chromatography/mass spectrometry). In L-NAME-treated PTs, but not in control PTs, 0.1 microM AA inhibited ouabain-sensitive (86)Rb uptake by > 40%; the response to AA was attenuated by DBDD. We conclude that, in the PTs, 1) 20-HETE is a second messenger for ET-1 and 2) conversion of AA to 20-HETE is augmented when NOS is inhibited.
Collapse
Affiliation(s)
- Bruno A Escalante
- Centro de Investigación y de Estudios Avanzados del Institúto Politécnico Nacional, Mexico
| | | | | |
Collapse
|
42
|
Pagel I, Langenickel T, Höhnel K, Philipp S, Nüssler AK, Blum WF, Aubert ML, Dietz R, Willenbrock R. Cardiac and renal effects of growth hormone in volume overload-induced heart failure: role of NO. Hypertension 2002; 39:57-62. [PMID: 11799079 DOI: 10.1161/hy0102.098323] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Growth hormone (GH) application is a new strategy in the treatment of heart failure. However, clinical and experimental investigations have shown contradictory effects of GH on cardiac performance. We tested the hypothesis that GH could improve cardiac and renal function in volume overload-induced heart failure. The effect of 4 weeks of GH treatment (2 mg/kg daily) was investigated in Wistar rats with aortocaval shunt. GH application did not influence left ventricular contractility and end-diastolic pressure in rats with aortocaval shunt. In contrast, GH treatment normalized impaired diuresis (vehicle 10.8+/-0.6 mL/d, GH 15.8+/-0.7 mL/d; P<0.05) and sodium excretion (vehicle 1.5+/-0.1 mmol/d, GH 2.2+/-0.1 mmol/d; P<0.001) in shunt-operated rats, with a similar increase of fractional sodium excretion. The urinary excretion of cGMP, the second messenger of atrial natriuretic peptide and NO, was higher in animals with shunts than in sham-operated animals and was further increased by GH (vehicle 293+/-38 nmol/d, GH 463+/-57 nmol/d; P<0.01). Although the atrial natriuretic peptide plasma levels were unchanged after GH, the excretion of NO metabolites (nitrate/nitrite) was elevated (vehicle 2020+/-264 nmol/d, GH 2993+/-375 nmol/d; P<0.05) in parallel with increased renal mRNA levels of inducible NO synthase 2. The changes of renal function after GH and the increased excretion of NO metabolites and cGMP were abolished by simultaneous treatment with the NO synthase inhibitor N(G)-nitro-L-arginine methyl ester. GH treatment did not influence cardiac function in rats with aortocaval shunts. However, GH improved renal function by increasing diuresis and sodium excretion. The responsible mechanism might be the enhanced activity of the renal NO system.
Collapse
Affiliation(s)
- Ines Pagel
- Franz-Volhard-Klinik at the Max-Delbrück-Center of Molecular Medicine, Charité, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Liang M, Berndt TJ, Knox FG. Mechanism underlying diuretic effect of L-NAME at a subpressor dose. Am J Physiol Renal Physiol 2001; 281:F414-9. [PMID: 11502590 DOI: 10.1152/ajprenal.2001.281.3.f414] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The diuretic effects of nitric oxide (NO) synthase inhibitors administered at subpressor dose in rats are controversial, and the tubular segments involved are not known. In the present study, we examined the effect of N(omega)-nitro-L-arginine methyl ester (L-NAME) at a subpressor dose on renal interstitial NO and cGMP activity and on renal tubular segmental reabsorption of fluid in the rat. Intravenous infusion of L-NAME at 1 microg. kg(-1). min(-1) in Sprague-Dawley rats (N = 8), which did not alter mean arterial pressure or glomerular filtration rate, significantly increased urine flow rate (U(v); from 78.2 +/- 12.7 to 117.1 +/- 14.9 microl/min, P < 0.05). Paradoxically, this effect of L-NAME was concomitant with significant increases in nitrite/nitrate (from 10.79 +/- 1.20 to 16.50 +/- 2.60 microM, P < 0.05) and cGMP (from 0.65 +/- 0.09 to 0.98 +/- 0.18 nM, P < 0.05) concentrations in renal cortical microdialysate as well as the nitrite/nitrate concentration in the medullary microdialysate. Micropuncture studies in the superficial nephron revealed that L-NAME significantly increased the flow rate (from 8.3 +/- 0.9 to 12.2 +/- 1.2 nl/min, P < 0.05) and fractional delivery of fluid to the distal tubule, but not those in the late proximal tubule. In conclusion, L-NAME, at the subpressor dose used in this study, increased renal nitrate/nitrite and cGMP and inhibited fluid reabsorption in tubular segments between the late proximal tubule and the distal tubule of superficial nephrons.
Collapse
Affiliation(s)
- M Liang
- Department of Medicine, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA
| | | | | |
Collapse
|
44
|
Jin XH, Siragy HM, Carey RM. Renal interstitial cGMP mediates natriuresis by direct tubule mechanism. Hypertension 2001; 38:309-16. [PMID: 11566896 DOI: 10.1161/01.hyp.38.3.309] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The objective of this study was to test the hypothesis that renal interstitial (RI) cGMP is natriuretic in vivo. In conscious rats (n=8), urinary sodium excretion (U(Na)V) was significantly greater on days 3 and 4 of RI infusion of cGMP (1.17+/-0.14 and 1.61+/-0.11 mmol/24 h, respectively) than during vehicle infusion (0.56+/-0.15 and 0.70+/-0.17 mmol/24 h, respectively) (P<0.01). Similarly, U(Na)V was greater on days 3 and 4 of RI infusion of 8-bromo-cGMP (2.15+/-0.42 and 2.16+/-0.1 mmol/24 h, respectively). Protein kinase G inhibitor Rp-8-pCPT-cGMPS reduced cGMP-induced and 8-bromo-cGMP-induced U(Na)V to control levels. Acute RI infusion of L-arginine (L-Arg, 40 mg. kg(-1). min(-1)), but not D-arginine, caused an increase in U(Na)V from 1.65+/-0.11 to 4.07+/-0.1 micromol/30 min (P<0.01). This increase was blocked by RI infusion of N(G)-nitro-L-arginine methyl ester (100 ng. kg(-1). min(-1)) by the phosphodiesterase (PDE II) activator 5,6DMcBIMP (0.01 micromol/microL), by PDE II (0.03 U. kg(-1). min(-1)) itself, or by the soluble guanylyl cyclase inhibitor 1-H-[1,2,4]oxadiazolo-[4,2-alpha]quinoxalin-1-one (ODQ, 0.12 mg. kg(-1). min(-1)). The PDE II activator also blocked L-Arg-stimulated cGMP levels. The NO donor S-nitroso-N-acetylpenicillamine (SNAP, 0.12 micromol. L(-1). kg(-1). min(-1)) increased U(Na)V from 1.65+/-0.11 to 2.93+/-0.08 micromol/30 min (P<0.01), and this response was blocked completely by ODQ. Renal arterial but not RI administration of the heat-stable enterotoxin of Escherichia coli induced natriuresis. RA infusion of cGMP (3 microg/min) increased U(Na)V, renal blood flow (RBF), and glomerular filtration rate (GFR). Renal cortical interstitial cGMP infusion increased U(Na)V with no effect on total RBF, renal cortical blood flow, or GFR. Similarly, the natriuretic actions of renal interstitial L-Arg or SNAP were not accompanied by any change in RBF or GFR. Medullary cGMP infusion had no effect on U(Na)V, total RBF, or medullary blood flow. Texas red-labeled cGMP infused via the RI space was distributed exclusively to cortical renal tubular cells. The results demonstrate that RI cGMP inhibits renal tubular sodium absorption via protein kinase G independently of hemodynamic changes. These observations indicate that the cortical interstitial compartment provides a potentially important domain for cell-to-cell signaling within the kidney.
Collapse
Affiliation(s)
- X H Jin
- Department of Medicine, University of Virginia, School of Medicine, Charlottesville, USA
| | | | | |
Collapse
|
45
|
Zimpelmann J, Burns KD. Angiotensin II AT(2) receptors inhibit growth responses in proximal tubule cells. Am J Physiol Renal Physiol 2001; 281:F300-8. [PMID: 11457722 DOI: 10.1152/ajprenal.2001.281.2.f300] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Angiotensin II (ANG II) subtype 2 (AT(2)) receptors are expressed in the adult kidney, but the effects of AT(2) receptor activation are unclear. The proximal tubule cell line LLC-PK(1) was transfected with a plasmid containing cDNA for the rat AT(2) receptor. In transfected cells, specific binding of (125)I-labeled ANG II was detected (dissociation constant = 0.81 nM), with inhibition by the AT(2) antagonist PD-123319, and no effect of the AT(1) antagonist losartan. ANG II (10(-7) M) significantly inhibited mitogen-activated protein kinase (MAPK) activity in transfected cells, associated with decreased phosphorylation of the extracellular signal-related kinases ERK1 and ERK2. ANG II stimulated phosphotyrosine phosphatase activity within 5 min, an effect blocked by PD-123319 and the phosphatase inhibitor vanadate. In transfected cells, ANG II inhibited epidermal growth factor-stimulated [(3)H]thymidine incorporation, an effect reversed by vanadate. In contrast, vanadate did not block ANG II-stimulated apoptosis of transfected cells. In summary, AT(2) receptors in proximal tubule cells inhibit MAPK activity and stimulate phosphotyrosine phosphatase. AT(2) receptor-induced inhibition of mitogenesis is mediated by phosphatase activation, whereas effects on apoptosis are insensitive to phosphatase inhibition. The data suggest that AT(2) receptors inhibit cell growth via distinct signaling pathways in the proximal tubule.
Collapse
Affiliation(s)
- J Zimpelmann
- Department of Medicine, Ottawa Hospital, and the Kidney Research Centre, Ottawa Health Research Institute, University of Ottawa, Ottawa, Ontario, Canada K1H 8L6
| | | |
Collapse
|
46
|
Ortiz PA, Garvin JL. NO Inhibits NaCl absorption by rat thick ascending limb through activation of cGMP-stimulated phosphodiesterase. Hypertension 2001; 37:467-71. [PMID: 11230320 DOI: 10.1161/01.hyp.37.2.467] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In the isolated, perfused rat thick ascending limb (THAL), L-arginine (L-Arg) stimulates endogenous nitric oxide (NO) production, which inhibits NaCl absorption. However, the intracellular cascade responsible for the effects of NO has not been studied. We hypothesized that endogenous NO inhibits THAL NaCl transport by increasing cGMP, which activates protein kinase G (PKG) and cGMP-stimulated phosphodiesterase (PDE II), which, in turn, decreases cAMP levels. THALs from rats were isolated and perfused, and net chloride flux (J(Cl-)) was measured. L-Arg was used to stimulate NO production. Adding L-Arg (0.5 mmol/L) to the bath decreased J(Cl-) from 154.4+/-9.9 to 101.9+/-14.1 pmol. mm(-1). min(-1), a 35.2% decrease (n=6; P<0.05). In the presence of the soluble guanylate cyclase inhibitor LY-83583 (10 micromol/L), adding L-Arg to the bath did not affect THAL J(Cl-) (143.7+/-28.1 versus 136.7+/-22.2 pmol. mm(-1). min(-1); n=6). LY-83583 alone had no effect on J(Cl-). In the presence of the PDE II inhibitor erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA) 50 micromol/L, L-Arg reduced J(Cl-) by only 13% (142.1+/-8.9 versus 122.7+/-11.5 pmol. mm(-1). min(-1); P<0.05; n=6). EHNA alone had no effect on THAL J(Cl-). In the presence of 10(-5) mol/L dibutyryl (db)-cAMP, L-Arg did not significantly reduce J(Cl-) (116.3+/-18.2 versus 102.6+/-15.6 pmol. mm(-1). min(-1); n=6). db-cAMP (10(-5) mol/L) had no effect on THAL J(Cl-). In the presence of the PKG inhibitor KT-5823 (2 micromol/L), L-Arg lowered J(Cl-) from 142.6+/-14.1 to 85.9+/-8.3 pmol. mm(-1). min(-1), a decrease of 35.6% (n=8; P<0.05). We conclude that (1) endogenous NO inhibits THAL J(Cl-) by stimulating soluble guanylate cyclase and increasing cGMP; (2) NO inhibits THAL J(Cl-) by stimulation of PDE II, which, in turn, decreases cAMP levels; and (3) PKG does not mediate NO-induced inhibition of THAL J(Cl-).
Collapse
Affiliation(s)
- P A Ortiz
- Division of Hypertension and Vascular Research, Henry Ford Hospital, Detroit, Michigan, USA
| | | |
Collapse
|
47
|
Díaz-Sylvester P, Mac Laughlin M, Amorena C. Peritubular fluid viscosity modulates H+ flux in proximal tubules through NO release. Am J Physiol Renal Physiol 2001; 280:F239-43. [PMID: 11208599 DOI: 10.1152/ajprenal.2001.280.2.f239] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We evaluated the effects of increasing the viscosity (eta) in peritubular capillary perfusates (PCP; 20 mM HNaPO4--Ringer, pH 7.4) on proximal convoluted tubule (PCT) acidification. Micropuncture experiments were performed with simultaneous luminal and peritubular perfusion. Changes in pH of a 20 mM HNaPO4--Ringer (pH 7.4 at t = 0) droplet placed in PCT lumen were measured with H+-sensitive microelectrodes. By adding neutral dextran (molecular wt 300,000-400,000) to the PCP, eta was increased. The effect of 10(-5) M ATP added to normal-eta PCP was evaluated. High eta increased H+ flux (85 and 97% when eta was increased 20 and 30%, respectively, above the control value). This increase was abolished by adding the nitric oxide antagonist N(omega)-nitro-L-arginine (L-NNA; 10(-4) M) or the purinoreceptor antagonists suramin (10(-4) M) and reactive blue 2 (3 x 10(-5) M). Addition of 5 x 10(-3) M L-arginine to the peritubular perfusate overcame the inhibitory effect of L-NNA on high-eta-induced increase in H+ flux. ATP increased H+ flux (80%), and this effect was blocked by L-NNA. These results suggest that changes in eta can modulate proximal H+ flux, at least in part, through ATP-dependent nitric oxide release from the endothelial cells of the peritubular capillaries.
Collapse
Affiliation(s)
- P Díaz-Sylvester
- Instituto de Investigaciones Cardiológicas-Consejo Nacional de Investigaciones Científicas y Técnicas, 1122 Buenos Aires, Argentina
| | | | | |
Collapse
|
48
|
Wang T, Inglis FM, Kalb RG. Defective fluid and HCO(3)(-) absorption in proximal tubule of neuronal nitric oxide synthase-knockout mice. Am J Physiol Renal Physiol 2000; 279:F518-24. [PMID: 10966931 DOI: 10.1152/ajprenal.2000.279.3.f518] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Using renal clearance techniques and in situ microperfusion of proximal tubules, we examined the effects of N(G)-monomethyl-L-arginine methyl ester (L-NAME) on fluid and HCO(3)(-) transport in wild-type mice and also investigated proximal tubule transport in neuronal nitric oxide synthase (nNOS)-knockout mice. In wild-type mice, administration of L-NAME (3 mg/kg bolus iv) significantly increased mean blood pressure, urine volume, and urinary Na(+) excretion. L-NAME, given by intravenous bolus and added to the luminal perfusion solution, decreased absorption of fluid (60%) and HCO(3)(-) (49%) in the proximal tubule. In nNOS-knockout mice, the urinary excretion of HCO(3)(-) was significantly higher than in the wild-type mice (3.12 +/- 0.52 vs. 1. 40 +/- 0.33 mM) and the rates of HCO(3)(-) and fluid absorption were 62 and 72% lower, respectively. Both arterial blood HCO(3)(-) concentration (20.7 vs. 25.7 mM) and blood pH (7.27 vs. 7.34) were lower, indicating a significant metabolic acidosis in nNOS-knockout mice. Blood pressure was lower in nNOS-knockout mice (76.2 +/- 4.6 mmHg) than in wild-type control animals (102.9 +/- 8.4 mmHg); however, it increased in response to L-NAME (125.5 +/- 5.07 mmHg). Plasma Na(+) and K(+) were not significantly different from control values. Our data show that a large component of HCO(3)(-) and fluid absorption in the proximal tubule is controlled by nNOS. Mice without this isozyme are defective in absorption of fluid and HCO(3)(-) in the proximal tubule and develop metabolic acidosis, suggesting that nNOS plays an important role in the regulation of acid-base balance.
Collapse
Affiliation(s)
- T Wang
- Departments of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | | | | |
Collapse
|
49
|
Vaziri ND, Ding Y, Sangha DS, Purdy RE. Upregulation of NOS by simulated microgravity, potential cause of orthostatic intolerance. J Appl Physiol (1985) 2000; 89:338-44. [PMID: 10904069 DOI: 10.1152/jappl.2000.89.1.338] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Prolonged exposure to microgravity during spaceflight or extended bed rest results in cardiovascular deconditioning, marked by orthostatic intolerance and hyporesponsiveness to vasopressors. Earlier studies primarily explored fluid and electrolyte balance and baroreceptor and vasopressor systems in search of a possible mechanism. Given the potent vasodilatory and natriuretic actions of nitric oxide (NO), we hypothesized that cardiovascular adaptation to microgravity may involve upregulation of the NO system. Male Wistar rats were randomly assigned to a control group or a group subjected to simulated microgravity by hindlimb unloading (HU) for 20 days. Tissues were harvested after death for determination of total nitrate and nitrite (NOx) as well as endothelial (e), inducible (i), and neuronal (n) NO synthase (NOS) proteins by Western blot. Separate subgroups were used to test blood pressure response to norepinephrine and the iNOS inhibitor aminoguanidine. Compared with controls, the HU group showed a significant increase in tissue NOx content and an upregulation of iNOS protein abundance in thoracic aorta, heart, and kidney and of nNOS protein expression in the brain and kidney but no discernible change in eNOS expression. This was associated with marked attenuation of hypertensive response to norepinephrine and a significant increase in hypertensive response to aminoguanidine, suggesting enhanced iNOS-derived NO generation in the HU group. Upregulation of these NOS isotypes can contribute to cardiovascular adaptation to microgravity by promoting vasodilatory tone and natriuresis and depressing central sympathetic outflow. If true in humans, short-term administration of an iNOS inhibitor may ameliorate orthostatic intolerance in returning astronauts and patients after extended bed rest.
Collapse
Affiliation(s)
- N D Vaziri
- Division of Nephrology and Hypertension, Department of Medicine, University of California, Irvine, California 92868, USA
| | | | | | | |
Collapse
|
50
|
Liang M, Knox FG. Production and functional roles of nitric oxide in the proximal tubule. Am J Physiol Regul Integr Comp Physiol 2000; 278:R1117-24. [PMID: 10801277 DOI: 10.1152/ajpregu.2000.278.5.r1117] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A significant role for nitric oxide (NO) in proximal tubule physiology and pathophysiology has been revealed by a series of in vivo and in vitro studies. Whether the proximal tubule produces NO under basal conditions is still controversial; however, evidence suggests that the proximal tubule is constantly exposed to NO that might include NO from nonproximal tubule sources. When challenged with a variety of stimuli, including hypoxia, the proximal tubule is able to produce large quantities of NO. In vivo studies generally indicate that NO inhibits fluid and sodium reabsorption by the proximal tubule. However, the final effect of NO on proximal tubular reabsorption appears to depend on the concentration of NO and involve interaction with other regulatory mechanisms. NO regulates Na(+)-K(+)-ATPase, Na(+)/H(+) exchangers, and paracellular permeability of proximal tubular cells, which may contribute to its effect on proximal tubular transport. Enhanced production of NO, perhaps depending on macrophage type inducible NO synthase, participates in hypoxic/ischemic proximal tubular injury. In conclusion, NO plays a fundamental role in both physiology and pathophysiology of the proximal tubule.
Collapse
Affiliation(s)
- M Liang
- Department of Medicine, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA
| | | |
Collapse
|