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Bancirova M. Paramecium caudatum
as a source of nitric oxide: Chemiluminescent detection based on Bluestar
®
Forensic reagent connected with microdialysis. LUMINESCENCE 2017; 32:1294-1298. [DOI: 10.1002/bio.3324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 02/27/2017] [Accepted: 03/01/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Martina Bancirova
- Department of Medical Chemistry and Biochemistry Palacky University Olomouc Czech Republic
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Layton AT, Edwards A. Predicted effects of nitric oxide and superoxide on the vasoactivity of the afferent arteriole. Am J Physiol Renal Physiol 2015; 309:F708-19. [PMID: 26180238 DOI: 10.1152/ajprenal.00187.2015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 07/09/2015] [Indexed: 12/19/2022] Open
Abstract
We expanded a published mathematical model of an afferent arteriole smooth muscle cell in rat kidney (Edwards A, Layton, AT. Am J Physiol Renal Physiol 306: F34-F48, 2014) to understand how nitric oxide (NO) and superoxide (O(2)(-)) modulate the arteriolar diameter and its myogenic response. The present model includes the kinetics of NO and O(2)(-) formation, diffusion, and reaction. Also included are the effects of NO and its second messenger cGMP on cellular Ca²⁺ uptake and efflux, Ca²⁺-activated K⁺ currents, and myosin light chain phosphatase activity. The model considers as well pressure-induced increases in O(2)(-) production, O(2)(-)-mediated regulation of L-type Ca²⁺ channel conductance, and increased O(2)(-) production in spontaneous hypertensive rats (SHR). Our results indicate that elevated O(2)(-) production in SHR is sufficient to account for observed differences between normotensive and hypertensive rats in the response of the afferent arteriole to NO synthase inhibition, Tempol, and angiotensin II at baseline perfusion pressures. In vitro, whether the myogenic response is stronger in SHR remains uncertain. Our model predicts that if mechanosensitive cation channels are not modulated by O(2)(-), then fractional changes in diameter induced by pressure elevations should be smaller in SHR than in normotensive rats. Our results also suggest that most NO diffuses out of the smooth muscle cell without being consumed, whereas most O(2)(-) is scavenged, by NO and superoxide dismutase. Moreover, the predicted effects of superoxide on arteriolar constriction are not predominantly due to its scavenging of NO.
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Affiliation(s)
- Anita T Layton
- Department of Mathematics, Duke University, Durham, North Carolina; and
| | - Aurélie Edwards
- Sorbonne Universités, UPMC Université Paris 06, Université Paris Descartes, Sorbonne Paris Cité, INSERM UMRS 1138, CNRS ERL 8228, Centre de Recherche des Cordeliers, Paris, France
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Ramirez-Garcia G, Martinez-Alfaro M, Gutierrez-Granados S, Alatorre-Ordaz A, Griveau S, Bedioui F. Electrochemical Assessment of Possible Melatonin Effect On Nitric Oxide Production From Kidneys Of Sub-Acute Lead Treated Rats. Electrochim Acta 2015. [DOI: 10.1016/j.electacta.2015.03.063] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Goud PT, Goud AP, Najafi T, Gonik B, Diamond MP, Saed GM, Zhang X, Abu-Soud HM. Direct real-time measurement of intra-oocyte nitric oxide concentration in vivo. PLoS One 2014; 9:e98720. [PMID: 24887331 PMCID: PMC4041775 DOI: 10.1371/journal.pone.0098720] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 05/06/2014] [Indexed: 11/18/2022] Open
Abstract
Nitric oxide (NO) is reported to play significant a role in oocyte activation and maturation, implantation, and early embryonic development. Previously we have shown that NO forms an important component of the oocyte microenvironment, and functions effectively to delay oocyte aging. Thus, precise information about intra-oocyte NO concentrations [NO] will result in designing more accurate treatment plans in assisted reproduction. In this work, the direct, real-time and quantitative intra-oocyte [NO] was measured utilizing an L-shaped amperometric integrated NO-selective electrode. This method not only provides an elegant and convenient approach to real-time the measurement of NO in physiological environments, but also mimics the loss of NO caused by rapid NO diffusion combined with its reactivity in the biological milieu. This experiment suggests that the NO levels of oocytes obtained from young animals are significantly higher than those of oocytes obtained from old animals. Additionally the NO levels stay constant during the measurements; however, the intra-oocyte [NO] is reduced significantly (70-75% reduction) in response to L-NAME incubation, suggesting that NO measurements are truly NOS based rather than caused by an unknown interfering substance in our system. We believe this first demonstration of the direct quantitative measurement of [NO] in situ in an intact cellular complex should be useful in tracking real-time and rapid changes at nanomolar levels. Moreover, this finding confirms and extends our previous work showing that supplementation with NO delays the oocyte aging process.
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Affiliation(s)
- Pravin T. Goud
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics & Gynecology, The C. S. Mott Center for Human Growth and Development, Wayne State University, Detroit, Michigan, United States of America
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of California Davis, Sacramento, California, United States of America
- California IVF Fertility Center, Davis and Sacramento, California, United States of America
| | - Anuradha P. Goud
- California National Primate Research Center, University California Davis, Davis, California, United States of America
| | - Tohid Najafi
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics & Gynecology, The C. S. Mott Center for Human Growth and Development, Wayne State University, Detroit, Michigan, United States of America
| | - Bernard Gonik
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics & Gynecology, The C. S. Mott Center for Human Growth and Development, Wayne State University, Detroit, Michigan, United States of America
| | - Michael P. Diamond
- Department of Obstetrics & Gynecology, Georgia Regents University, Augusta, Georgia, United States of America
| | - Ghassan M. Saed
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics & Gynecology, The C. S. Mott Center for Human Growth and Development, Wayne State University, Detroit, Michigan, United States of America
| | - Xueji Zhang
- World Precision Instruments, Sarasota, Florida, United States of America
- Research Center for Bioengineering & Sensing Technology, University of Science & Technology, Beijing, P.R. China
| | - Husam M. Abu-Soud
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics & Gynecology, The C. S. Mott Center for Human Growth and Development, Wayne State University, Detroit, Michigan, United States of America
- Department of Biochemistry and Molecular Biology, Wayne State University, School of Medicine, Detroit, Michigan, United States of America
- * E-mail:
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Nitric oxide release follows endothelial nanomechanics and not vice versa. Pflugers Arch 2010; 460:915-23. [PMID: 20809399 DOI: 10.1007/s00424-010-0871-8] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Revised: 08/05/2010] [Accepted: 08/09/2010] [Indexed: 12/27/2022]
Abstract
In the vascular endothelium, mechanical cell stiffness (К) and nitric oxide (NO) release are tightly coupled. "Soft" cells release more NO compared to "stiff" cells. Currently, however, it is not known whether NO itself is the primary factor that softens the cells or whether NO release is the result of cell softening. To address this question, a hybrid fluorescence/atomic force microscope was used in order to measure changes in К and NO release simultaneously in living vascular endothelial cells. Aldosterone was applied to soften the cells transiently and to trigger NO release. NO synthesis was then either blocked or stimulated and, simultaneously, К was measured. Cell indentation experiments were performed to evaluate К, while NO release was measured either by an intracellular NO-dependent fluorescence indicator (DAF-FM/DA) or by NO-selective electrodes located close to the cell surface. After the application of aldosterone, К decreases, within 10 min, to 80.5 ± 1.7% of control (100%). DAF-FM fluorescence intensity increases simultaneously to 132.9 ± 2.2%, which indicates a significant increase in the activity of endothelial NO synthase (eNOS). Inhibition of eNOS (by N (ω)-nitro-L: -arginine methyl ester) blocks the NO release, but does not affect the aldosterone-induced changes in К. Application of an eNOS-independent NO donor (NONOate/AM) raises intracellular NO concentration, but, again, does not affect К. Data analysis indicates that a decrease of К by about 10% is sufficient to induce a significant increase of eNOS activity. In conclusion, these nanomechanic properties of endothelial cells in vascular endothelium determine NO release, and not vice versa.
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Kawada H, Yasuoka Y, Fukuda H, Kawahara K. Low [NaCl]-induced neuronal nitric oxide synthase (nNOS) expression and NO generation are regulated by intracellular pH in a mouse macula densa cell line (NE-MD). J Physiol Sci 2009; 59:165-73. [PMID: 19340543 PMCID: PMC10716943 DOI: 10.1007/s12576-009-0022-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2008] [Accepted: 01/14/2009] [Indexed: 10/20/2022]
Abstract
Changes in the luminal NaCl concentration ([NaCl]) at the macula densa (MD) modulate the tubuloglomerular feedback (TGF) responses via an affect on the release of nitric oxide (NO). This study was performed in a newly established mouse macula densa cell line (NE-MD) to investigate the effects of lowering [NaCl] on the neuronal NO synthase (nNOS) protein expression and L-arginine (Arg)-induced NO release. Expression of nNOS protein and release of NO were evaluated by Western blot analysis and an NO-sensitive electrode, respectively. Intracellular pH (pH(i)) was monitored by the BCECF assay. Although there was weak staining of the nNOS protein expression, L-Arg-induced NO generation was negligible in normal (140 mM NaCl) solution. Both were significantly (P < 0.05) increased either in the presence of furosemide (12 microM), an inhibitor of the Na(+)-K(+)-2Cl(-) cotransporter, or in a low (23 mM) Cl(-) solution. Furosemide- and low Cl(-)-induced NO generation was completely inhibited by 50 microM 7-nitroindasole (7-NI), a nNOS inhibitor. Moreover, these increases were significantly (P < 0.05) inhibited by the addition of 100 microM amiloride, an inhibitor of the Na(+)/H(+) exchanger, or by its analogue 5-(N)-ethyl-N-isopropyl amiloride (EIPA), and also at a lower pH of 7.1. Furthermore, nNOS expression and NO release were not stimulated in as low as 19 mM Na(+) solution. In conclusion, low [Cl(-)], but not low [Na(+)] in the lumen at the MD, increased nNOS protein expression and NO generation. Changes in the luminal [NaCl] may modulate the TGF system via an effect on the NO generation from the MD.
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Affiliation(s)
- Hideaki Kawada
- Department of Cellular and Molecular Physiology, Kitasato University Graduate School of Medical Sciences, Sagamihara, Japan
| | - Yukiko Yasuoka
- Department of Cellular and Molecular Physiology, Kitasato University Graduate School of Medical Sciences, Sagamihara, Japan
- Department of Physiology, Kitasato University School of Medicine, Kitasato 1-15-1, Sagamihara, 228-8555 Japan
| | - Hidekazu Fukuda
- Department of Physiology, Kitasato University School of Medicine, Kitasato 1-15-1, Sagamihara, 228-8555 Japan
| | - Katsumasa Kawahara
- Department of Cellular and Molecular Physiology, Kitasato University Graduate School of Medical Sciences, Sagamihara, Japan
- Department of Physiology, Kitasato University School of Medicine, Kitasato 1-15-1, Sagamihara, 228-8555 Japan
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Khajanchee YS, Swanström LL. Real-time dynamics of nitric oxide shifts within the esophageal wall. Surg Endosc 2009; 23:2273-8. [PMID: 19263142 DOI: 10.1007/s00464-009-0361-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2008] [Revised: 01/05/2009] [Accepted: 01/12/2009] [Indexed: 11/30/2022]
Abstract
BACKGROUND Currently, indirect evidence suggests that the neurotransmitter nitric oxide (NO) plays a crucial role in the genesis of aboral propagation of esophageal peristalses during swallowing. However, direct evidence in this regard currently is lacking. This study aimed to assess the feasibility of using NO-selective microprobes to detect real-time NO changes within the esophageal wall of North American opossums (Didelphis virginiana) during normal progressive esophageal peristalsis and induced esophageal dysmotility. METHODS Six adult opossums of both sexes (mean weight, 2.28 +/- 0.41 kg) were included in the study. All had normal esophageal motility, as documented by water-perfused esophageal manometry. A calibrated carbon fiber NO-selective microelectrode (ISNOP30, ISNOP100) was placed within the smooth muscle portion of the esophageal wall, and changes in NO levels were measured as redox current in pico-amperes (pA) with the Apollo-4000 NO meter. The dynamics of NO in response to reflexive deglutition were assessed during both normal propagative peristalsis and abnormal esophageal contractions induced by intravenous (i.v.) administration of the neural NO synthase inhibitor L-nitro L-arginine methyl ester (L-NAME) and banding of the gastroesophageal junction (GEJ) for 4-weeks. RESULTS During normal propagative esophageal peristalsis, a mean change of 2,158.85 +/- 715.93 pA was measured by the NO meter. Intravenous administration of L-NAME and chronic banding of the GEJ induced achalasia-like esophageal contractions. A significantly smaller change in levels of NO was detected within the esophageal wall during dysfunctional motility (331.94 +/- 188.17 pA; p < 0.001) than during normal propagative peristalsis (579 +/- 385 pA; p < 0.001). CONCLUSION The results of this study indicate that carbon fiber NO-selective microprobes can successfully measure changes in the concentration of NO, an important inhibitory neurotransmitter, within the esophageal wall and that these preliminary data support the involvement of this crucial neurotransmitter in programming normal propagation of peristaltic waves within the esophagus.
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Affiliation(s)
- Yashodhan S Khajanchee
- Minimally Invasive Surgery Program, Legacy Health System, 1040 NW 22nd Avenue, Suite 560, Portland, OR 97210, USA.
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YUASA M, KOBAYASHI T, AOKI T, FUJII H, IGARASHI M, MURATA H. Detection of Superoxide Anion Radical Using Iron Porphyrin Complexes Bound to Electropolymerized Axial Ligands. ELECTROCHEMISTRY 2009. [DOI: 10.5796/electrochemistry.77.940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Levine DZ, Iacovitti M, Robertson SJ. Modulation of single-nephron GFR in thedb/dbmouse model of type 2 diabetes mellitus. II. Effects of renal mass reduction. Am J Physiol Regul Integr Comp Physiol 2008; 294:R1840-6. [DOI: 10.1152/ajpregu.00457.2007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study examines for the first time the effects of uninephrectomy (Nx) on modulation of whole kidney glomerular filtration rate (GFR), single-nephron GFR (SNGFR), and progression of diabetic nephropathy in the db/db mouse model of type 2 diabetes mellitus. To characterize SNGFR and tubuloglomerular feedback (TGF) responses to Nx and chronic neuronal nitric oxide synthase inhibition in the db/db mouse, we studied the effects of Nx on whole kidney GFR, SNGFR, and TGF characteristics in db/db and wild-type (WT) mice after Nx or sham Nx. We also documented progression of glomerular changes over a 6-mo period. Whole kidney GFR and SNGFR were significantly higher in db/db Nx than db/db sham mice, without change in proximal tubule reabsorptive rates. The TGF responses, determined as proximal-distal SNGFR differences, were brisk: 12.1 ± 1.0 vs. 8.4 ± 0.6 nl/min in WT sham ( P < 0.05), 15.7 ± 1.0 vs. 12.0 ± 1.0 nl/min in WT Nx ( P < 0.05), and 17.8 ± 1.3 vs. 14.3 ± 1.0 nl/min in db/db Nx ( P < 0.05) mice. Chronic ingestion of the neuronal nitric oxide synthase inhibitor S-methylthiocitrulline for 2–3 wk after Nx had no effect on SNGFR or the TGF response. These studies show further elevations in whole kidney GFR and SNGFR in these hyperglycemic morbidly obese db/db mice, with an intact TGF system after Nx. In addition, in the db/db Nx mice, 4–6 mo after Nx, there was an exacerbation of the lesions of diabetic nephropathy, as quantified by a significant increase in the ratio of mesangial surface area to total glomerular surface area.
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Can rodent models of diabetic kidney disease clarify the significance of early hyperfiltration?: recognizing clinical and experimental uncertainties. Clin Sci (Lond) 2008; 114:109-18. [PMID: 18062776 DOI: 10.1042/cs20070088] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In the past, hyperfiltration and increased glomerular capillary pressure have been identified as important determinants of the development of DN (diabetic nephropathy). Recently, some basic research and clinical reviews on DN have omitted identifying hyperfiltration as an important risk factor. At the same time, different rodent models of DN have been described without and with documented hyperfiltration. In the present review, the importance of hyperfiltration is reassessed, reviewing key clinical and research studies, including the first single nephron studies in a mouse model of DN. From clinical studies of Type 1 and Type 2 diabetes mellitus, it is clear that many patients do not have early hyperfiltration and, even when present, its contribution to subsequent DN remains uncertain. Key mechanisms underlying hyperfiltration in rodent models are reviewed. Findings on intrarenal NO metabolism and the control of single-nephron GFR (glomerular filtration rate) in rodent models of DN are also presented. Characterization of valid experimental models of DN should include a careful delineation of the absence or presence of early hyperfiltration, with special efforts made to establish the specific role hyperfiltration may play in the emergence of DN.
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Abstract
Since nitric oxide (NO) was identified as the endothelial-derived relaxing factor in the late 1980s, many approaches have attempted to provide an adequate means for measuring physiological levels of NO. Although several techniques have been successful in achieving this aim, the electrochemical method has proved the only technique that can reliably measure physiological levels of NO in vitro, in vivo, and in real time. We describe here the development of electrochemical sensors for NO, including the fabrication of sensors, the detection principle, calibration, detection limits, selectivity, and response time. Furthermore, we look at the many experimental applications where NO selective electrodes have been successfully used.
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Affiliation(s)
- Ian R Davies
- World Precision Instruments Limited, Aston, United Kingdom
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YUASA M, OYAIZU K, MURATA H, TOYODA Y, NAMBA M, SHITARA M. Synthesis of Six-coordination Proximal Base Conjugation Iron(III) porphyrin Complexes and Evaluation as a Superoxide Sensor. KOBUNSHI RONBUNSHU 2008. [DOI: 10.1295/koron.65.349] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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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.
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Affiliation(s)
- Stephen Kempson
- Department of Cellular and Integrative Physiology, Indiana University Medical School, 635 Barnhill Drive, Indianapolis, IN 46202, USA
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Abstract
Early diabetes is often accompanied by an increased glomerular filtration rate (GFR). This hyperfiltration, which is significantly dependent upon increased nitric oxide activity, is believed to contribute to progression of diabetic nephropathy. In this article, a technique for the measurement of tubular fluid nitric oxide in vivo, in real time, is reviewed, and findings in three commonly used rodent models of diabetes are described. The mechanisms of altered tubuloglomerular feedback (TGF) in diabetes are also reviewed, with emphasis on hyperfiltration and the role of nitric oxide. New findings on the modulation of hyperfiltration in the classic type 2 diabetes db/db mouse are presented, showing suppression of the TGF mechanism and modulation of single-nephron GFR by a specific nitric oxide synthase inhibitor.
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Affiliation(s)
- David Z Levine
- The Kidney Research Centre, Ottawa Health Research Institute and University of Ottawa, 451 Smyth Road, Room 1333, Ottawa, Ontario, K1H 8M5 Canada.
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Levine DZ, Iacovitti M. Real-time measurement of kidney tubule fluid nitric oxide concentrations in early diabetes: Disparate changes in different rodent models. Nitric Oxide 2006; 15:87-92. [PMID: 16510300 DOI: 10.1016/j.niox.2005.11.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2005] [Revised: 11/02/2005] [Accepted: 11/02/2005] [Indexed: 11/24/2022]
Abstract
There are several reports indicating that nitric oxide (NO) plays a role in the kidney hyperfiltration seen in the early stages of diabetes mellitus (DM). Whole kidney GFR and single nephron GFR (SNGFR) have been reported to decrease after nitric oxide synthase (NOS) inhibition. To date, no direct, in vivo, quantitative NO measurements have been made within the kidney in any models of early diabetes. To assess the possible association of changes in tubular fluid nitric oxide concentrations (TF [NO]) with early diabetes, a specially modified NO electrode with a tip diameter of about 7 microm was used to measure NO in single tubules in seven rodent groups. In the Sprague-Dawley (SD) rat model, TF [NO] increased by 50% after streptozotocin (STZ) induced DM1. In the B6129G2/J mouse, control TF [NO] was more than twice the rat control value and fell by 50% after STZ treatment. In three other groups of mice-db/db (B6.Cg-m+/+Lepr(db)/J) Type II diabetic (DM2) mouse, db/m (its heterozygote), and the corresponding wild type (WT)-TF [NO] was also much higher than in the rat, and unlike the B6129G2/J STZ diabetic mouse, did not change after the onset of diabetes. Blood glucose concentrations were similar in the three diabetic groups. Accordingly, in different rodent models of diabetes, in vivo TF [NO], measured in real time, varies significantly in control animals and directionally in different models of DM1 and DM2.
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Affiliation(s)
- David Z Levine
- Division of Nephrology, The Kidney Research Centre, Ottawa Health Research Institute and University of Ottawa, Ottawa, Ont., Canada.
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YUASA M, OYAIZU K, MURATA H, ISHIKAWA M, TSUTSUI S, NAMBA M. Fabrication of Electrodes for Highly Sensitive Detection of a Superoxide Anion Radical by Electropolymerization of Thienylporphyrins in the Prescence of Thiophene and Application to Active Oxygen Sensors. KOBUNSHI RONBUNSHU 2006. [DOI: 10.1295/koron.63.427] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Yip KP. Flash photolysis of caged nitric oxide inhibits proximal tubular fluid reabsorption in free-flow nephron. Am J Physiol Regul Integr Comp Physiol 2005; 289:R620-R626. [PMID: 15790750 DOI: 10.1152/ajpregu.00610.2004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A nonobstructing optical method was developed to measure proximal tubular fluid reabsorption in rat nephron at 0.25 Hz. The effects of uncaging luminal nitric oxide (NO) on proximal tubular reabsorption were investigated with this method. Proximal fluid reabsorption rate was calculated as the difference of tubular flow measured simultaneously at two locations (0.8-1.8 mm apart) along a convoluted proximal tubule. Tubular flow was estimated on the basis of the propagating velocity of fluorescent dextran pulses in the lumen. Changes in local tubular flow induced by intratubular perfusion were detected simultaneously along the proximal tubule, indicating that local tubular flow can be monitored in multiple sites along a tubule. The estimated tubular reabsorption rate was 5.52 +/- 0.38 nl.min(-1).mm(-1) (n = 20). Flash photolysis of luminal caged NO (potassium nitrosylpentachlororuthenate) was induced with a 30-Hz UV nitrogen-pulsed laser. Release of NO from caged NO into the proximal tubule was confirmed by monitoring intracellular NO concentration using a cell-permeant NO-sensitive fluorescent dye (DAF-FM). Emission of DAF-FM was proportional to the number of laser pulses used for uncaging. Photolysis of luminal caged NO induced a dose-dependent inhibition of proximal tubular reabsorption without activating tubuloglomerular feedback, whereas uncaging of intracellular cGMP in the proximal tubule decreased tubular flow. Coupling of this novel method to measure reabsorption with photolysis of caged signaling molecules provides a new paradigm to study tubular reabsorption with ambient tubular flow.
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Affiliation(s)
- Kay-Pong Yip
- Dept. of Physiology and Biophysics, College of Medicine, University of South Florida, MDC 8, 12901 Bruce B. Downs Blvd., Tampa, FL 33612, USA.
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Pittner J, Wolgast M, Casellas D, Persson AEG. Increased shear stress–released NO and decreased endothelial calcium in rat isolated perfused juxtamedullary nephrons. Kidney Int 2005; 67:227-36. [PMID: 15610246 DOI: 10.1111/j.1523-1755.2005.00073.x] [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: 11/30/2022]
Abstract
BACKGROUND Nitric oxide is an important vasodilator released from endothelial cells by the calcium-dependent endothelial nitric oxide synthase (NOS). We considered it important to investigate how shear stress/perfusion pressure influenced endothelial cell calcium concentration, nitric oxide release, and autoregulation of the afferent arteriole, since this arteriole controls glomerular filtration rate (GFR) and renin release. METHODS We used an isolated perfused juxtamedullary nephron preparation and measured calcium with Fura 2, nitric oxide with 4-amino-5 methylamino-2', 7'-difluorescein (DAF-FM) and diameter with an imaging system. A mathematical model was applied to calculate changes in nitric oxide concentration and shear stress/wall tension during perfusion with and without erythrocytes at perfusion pressures varying from 50 to 150 mm Hg. RESULT Cell-free perfusion increased nitric oxide concentration and abolished autoregulation; addition of erythrocytes or l-arginine analog N-nitro-l-arginine methyl ester (L-NAME) decreased nitric oxide concentration and reinstated autoregulation. Elevated perfusion pressure/elevated shear stress increased nitric oxide release and surprisingly decreased the endothelial cell calcium concentration, with perfusion pressure increase from 50 to 150 mm Hg, using blood perfusion endothelial calcium concentration decreased from 186 +/- 39 to 76 +/- 25 nmol/L and with cell-free perfusion from 116 +/- 33 to 56 +/- 21 nmol/L. CONCLUSION Nitric oxide scavenging by erythrocytes has a high impact on arteriolar nitric oxide concentration and autoregulatory response. Nitric oxide measurements in endothelial cells of the afferent arteriole showed that increased perfusion pressure/shear stress increased nitric oxide release, while simultaneously endothelial cell calcium concentration decreased, possibly indicating a feedback control of this calcium by nitric oxide release.
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Affiliation(s)
- János Pittner
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
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Yuasa M, Oyaizu K, Yamaguchi A, Ishikawa M, Eguchi K, Kobayashi T, Toyoda Y, Tsutsui S. Electrochemical sensor for superoxide anion radical using polymeric iron porphyrin complexes containing axial 1-methylimidazole ligand as cytochromec mimics. POLYM ADVAN TECHNOL 2005. [DOI: 10.1002/pat.590] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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20
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Huang CJ, Tsai PS, Pan WHT, Skimming JW. Microdialysis for measurement of hepatic and systemic nitric oxide biosynthesis in septic rats. Acta Anaesthesiol Scand 2005; 49:28-34. [PMID: 15675978 DOI: 10.1111/j.1399-6576.2005.00486.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND We sought to compare two techniques, microdialysis and repeated blood withdrawal, for serial assessment of hepatic and systemic nitric oxide (NO) biosynthesis in septic rats. METHODS Rats were randomly allocated to either microdialysis or blood withdrawal groups. Two microdialysis probes, one in liver and the other in right atrium, were placed in rats in the microdialysis group. Half of the rats from each group were then given lipopolysaccharide (LPS) to induce NO production. The other half of the rats from each group were injected with vehicle (normal saline) to serve as controls. In the microdialysis group, dialysate (30 microl) was collected every 30 min. In the blood withdrawal group, 0.3 ml of blood was drawn every 30 min. Sampling was performed up to 6 h after injection of LPS or vehicle. Hemodynamics, hepatic and systemic NO concentrations, and iNOS expression in harvested liver tissues were assayed. RESULTS Repeated blood withdrawal by itself caused a significant decrease in blood pressure and induced hepatic iNOS expression. Microdialysis, on the contrary, reliably detected LPS-induced NO production without resulting either in hemodynamic changes or in iNOS induction in liver tissue. CONCLUSIONS Microdialysis provides serial measure of hepatic and systemic NO concentrations in LPS-treated rats without the need for removal of tissue.
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Affiliation(s)
- C-J Huang
- Institute of Pharmacology, National Yang-Ming University, Taipei, Taiwan
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Prabhakar SS. Regulatory and functional interaction of vasoactive factors in the kidney and extracellular pH. Kidney Int 2004; 66:1742-54. [PMID: 15496145 DOI: 10.1111/j.1523-1755.2004.00951.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A growing body of evidence suggests that vasoactive factors produced in the kidney such as nitric oxide, endothelins, angiotensin, and prostaglandins participate actively in the regulation of acid-base homeostasis under physiologic conditions. In addition, recent reports indicate that alterations in the systemic acid-base status may also influence the generation of vasoactive cytokines in the kidney, which in turn may mediate the renal effector processes that tend to restore normality under such conditions. Metabolic acidosis, which so frequently accompanies many forms of chronic renal failure (CRF), may contribute to down-regulation of intrarenal nitric oxide production that characterizes CRF. Reduced extracellular pH inhibits inducible nitric oxide production in mesangial cells by altering the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) oxidation, an important posttranslational mechanism in the inducible nitric oxide synthase (iNOS) activation. The underlying defects resulting in the uncoupling of NADPH oxidation in acidemic microenvironment are discussed. Acidosis stimulates renal production of endothelins, which mediate proximal tubular acidification by enhancing sodium-hydrogen exchanger-3 (NHE-3) activity. Renal endothelins mediate enhanced urinary acid excretion following dietary acid ingestion, an effect that is effectively blocked by endothelin receptor blockers. Reduced extracellular pH stimulates endothelin secretion from renal microvascular endothelial cells, which may promote enhanced acid excretion from the distal tubule under conditions of acidosis. These phenomena as well as the role of angiotensin and renal prostaglandins in mediating renal acidification in normal and acidotic conditions are discussed in this review, which describe the regulatory interaction between extracellular pH and renal vasoactive factors.
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Affiliation(s)
- Sharma S Prabhakar
- Division of Nephrology, Department of Internal Medicine, Texas Tech Health Science Center, Lubbock, Texas 79430, USA.
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22
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Abstract
Macula densa cells couple renal haemodynamics, glomerular filtration and renin release with tubular fluid salt and water reabsorption. These cells detect changes in tubular fluid composition through a complex of intracellular signalling events that are mediated by membrane transport pathways. Increases in luminal fluid sodium chloride concentration result in alterations in cell sodium chloride concentration, cytosolic calcium, cell pH, basolateral membrane depolarization and cell volume. Macula densa signalling then involves the production and release of specific paracrine signalling molecules at their basolateral membrane. Upon moderate increases in luminal sodium chloride concentration macula densa cells release increasing amounts of ATP and decreasing amounts of prostaglandin E(2), thereby increasing afferent arteriolar tone and decreasing the release of renin from granular cells. On the other hand, further increases in luminal concentration stimulate the release of nitric oxide, which serve to prevent excessive tubuloglomerular feedback vasoconstriction. Paracrine signalling by the macula densa cells therefore controls juxtaglomerular function, renal vascular resistance and participates in the regulation of renin release.
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Affiliation(s)
- P Komlosi
- Department of Medicine, Division of Nephrology, University of Alabama at Birmingham, USA
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Levine DZ, Burns KD, Jaffey J, Iacovitti M. Short-term modulation of distal tubule fluid nitric oxide in vivo by loop NaCl reabsorption. Kidney Int 2004; 65:184-9. [PMID: 14675049 DOI: 10.1111/j.1523-1755.2004.00361.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Intrarenal nitric oxide (NO) production and signaling effects are influenced by NaCl loading. To gain further insight into NO mechanisms we determined whether rat distal tubular fluid (DTF) [NO] and collected NO may acutely change when NaCl loop delivery is altered. METHODS An NO microelectrode was used to measure real-time DTF [NO] and DT-collected NO. With proximal flow blocked (open system), 150 mmol/L NaCl, with and without 10(-4) mol/L furosemide was perfused with measurement of loop [Cl] reabsorption. Using a closed system, DTF [NO] was also determined using several different loop perfusates. RESULTS In the open system, perfusion with 40 nL/min of 150 mmol/L NaCl to which 10(-4) mol/L furosemide was added, DT [NO] and DT-collected NO was approximately twice that measured with perfusion of 150 mmol/L NaCl alone, while loop Cl reabsorption decreased by half. In the closed system, perfusion at 10 nL/min of 150 mmol/L NaCl + furosemide 10(-4) mol/L also induced a significant rise in DTF [NO] and collected NO. Perfusion of 10(-3) mol/L S-methyl-L-thiocitrulline (SMTC) with 150 mmol/L NaCl, induces a significant drop in DT [NO], but without a significant increase in collected NO. Furthermore, with addition of 10(-3) mol/L SMTC to the 150 mmol/L NaCl + 10(-4) furosemide perfusate, the rise in DT [NO] was prevented. Analysis of covariance showed that flow changes within, or between all groups, had no significant additional effect. CONCLUSION In both open and closed loop perfusion systems, 10(-4) mol/L furosemide inhibition of NaCl transport stimulates net loop NO emission independent of flow; 10(-3) mol/L SMTC + 150 mmol/L NaCl reduces DT [NO], but not DT-collected NO. Short-term net NO emission from the entire loop, as collected in distal tubule fluid, increases with inhibition of loop NaCl transport.
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Affiliation(s)
- David Z Levine
- Division of Nephrology, The Kidney Research Centre, Ottawa Health Research Institute, Ottawa, Ontario, Canada.
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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.
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Affiliation(s)
- Joseph Zimpelmann
- Division of Nephrology, The Ottawa Hospital and University of Ottawa, 1967 Riverside Drive, Ottawa, Ontario, Canada K1H 7W9
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25
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Real Time Microelectrode Measurement of Nitric Oxide in Kidney Tubular Fluid in vivo. SENSORS 2003. [DOI: 10.3390/s30800314] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Abstract
The tubuloglomerular feedback response, the change in afferent arteriolar tone caused by a change in NaCl concentration at the macula densa, is likely initiated by the generation of a vasoactive mediator within the confines of the juxtaglomerular apparatus. Substantial progress has been made in identifying the nature of this mediator and the factors that modulate its effect on vascular tone. In support of earlier studies using P1 purinergic antagonists, the application of the knockout technique has shown that adenosine 1 receptors are absolutely required for eliciting TGF responses. The background level of angiotensin II appears to be an important cofactor determining the efficiency of A1AR-induced vasoconstriction, probably through a synergistic interaction at the level of the G protein-dependent transduction mechanism. The source of the adenosine is still unclear, but it is conceivable that adenosine is generated extracellularly from released ATP through a cascade of ecto-nucleotidases. There is also evidence that ATP may activate P2 receptors in preglomerular vessels, which may contribute to autoregulation of renal vascular resistance. Nitric oxide (NO), generated by the neuronal isoform of nitric oxide synthase in macula densa cells, reduces the constrictor effect of adenosine, but the regulation of NO release and its exact role in states of TGF-induced hyperfiltration are still unclear.
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Affiliation(s)
- Jürgen Schnermann
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-1370, USA.
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De La Cruz JP, González-Correa JA, Guerrero A, Márquez E, Martos F, Sánchez De La Cuesta F. Differences in the effects of extended-release aspirin and plain-formulated aspirin on prostanoids and nitric oxide in healthy volunteers. Fundam Clin Pharmacol 2003; 17:363-72. [PMID: 12803576 DOI: 10.1046/j.1472-8206.2003.00137.x] [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: 01/04/2023]
Abstract
This study was designed to evaluate the effects of extended-release aspirin on platelet aggregation and the production of prostanoids and nitric oxide. The participants in this double blind, randomized and crossover study were 20 healthy volunteers. Interventions were 150 mg of plain-formulated aspirin (PFASA) and 150 mg of extended-release aspirin (ERASA). Blood samples were collected before and 10, 20, 60, 120, 240, 480 and 1440 min after the first dose; 3, 7 and 14 days after daily administration and 24 h after the last dose. The main measures were platelet aggregometry, thromboxane B2, 6-keto-prostaglandin (PG) F1alpha and nitric oxide in each control. Platelet aggregation was inhibited by 50% with ERASA, and by 77% with PFASA. No differences were found in chronic treatment. Thromboxane B2 was inhibited more by the latter (51-67%), but 90% inhibition was observed in both groups after 3 days. The levels of 6-keto-PGF1alpha was reduced by 20% with ERASA and by 58% with PFASA. Nitric oxide production increased in both groups, but after 24 h, and 7-14 days, elevated concentrations of nitric oxide were found only in the ERASA. The antiplatelet effects of ERASA provide pharmacological advantages (greater prostacyclin synthesis and prolonged increase in nitric oxide production) over those provided by the plain formulation.
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Affiliation(s)
- J P De La Cruz
- Department of Pharmacology and Therapeutics, School of Medicine, University of Malaga, 29071 Malaga, Spain.
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Wang T. Role of iNOS and eNOS in modulating proximal tubule transport and acid-base balance. Am J Physiol Renal Physiol 2002; 283:F658-62. [PMID: 12217856 DOI: 10.1152/ajprenal.00243.2001] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Our laboratory has previously shown that mice lacking neuronal nitric oxide synthase (nNOS) are defective in fluid absorption (J(v)) and HCO absorption (J(HCO3)) in the proximal tubule and develop metabolic acidosis. The present study examined the transport of fluid and HCO in the proximal tubule and acid-base status in mice lacking two other isoforms of NOS, inducible NOS (iNOS) and endothelial NOS (eNOS). Proximal tubules were microperfused in situ in wild-type and NOS knockout mice by methods previously described (Wang T, Yang C-L, Abbiati T, Schultheis PJ, Shull GE, Giebisch G, and Aronson PS. Am J Physiol Renal Physiol 277: F298-F302, 1999). [(3)H]inulin and total CO(2) concentrations were measured in the perfusate and collected fluid, and net J(v) and J(HCO3) were analyzed. These data show that J(HCO3) was 35% lower (71.7 +/- 6.4 vs. 109.9 +/- 7.3 pmol x min(-1) x mm(-1), n = 13, P < 0.01) and J(v) was 38% lower (0.95 +/- 0.15 vs. 1.54 +/- 0.17 nl. min(-1) x mm(-1), n = 13, P < 0.05) in iNOS knockout mice compared with their wild-type controls. Addition of the iNOS-selective inhibitor L-N(6)-(1-iminoethyl) lysine, reduced both J(v) and J(HCO3) significantly in wild-type, but not in iNOS knockout, mice. In contrast, both J(HCO3) (93.3 +/- 7.9 vs. 110.6 +/- 6.18 pmol x min(-1) x mm(-1)) and J(v) (1.56 +/- 0.17 vs. 1.55 +/- 0.16 nl. min(-1) x mm(-1)) did not change significantly in eNOS knockout mice. These results indicated that iNOS upregulates Na(+) and HCO transport, whereas eNOS does not directly modulate Na(+) and HCO transport in the kidney proximal tubules.
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Affiliation(s)
- Tong Wang
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
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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.
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Affiliation(s)
- Andrew Baines
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada M5G 1L5.
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Zhang X, Kislyak Y, Lin J, Dickson A, Cardosa L, Broderick M, Fein H. Nanometer size electrode for nitric oxide and S-nitrosothiols measurement. Electrochem commun 2002. [DOI: 10.1016/s1388-2481(01)00265-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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