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Integrative Physiology |
From the Departamento de Farmacología (J.V.E.) and Unidad Mixta Universidad de ValenciaFundación Centro Nacional de Investigaciones Cardiovasculares Carlos III (C.N., V.M.V., R.T., P.D.), Facultad de Medicina, Universidad de Valencia, Blasco Ibáñez, Valencia, Spain; Unidad de Citometria, Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III (A.A.-B.), C/Melchor Fernández Almagro, Madrid, Spain; and The Wolfson Institute for Biomedical Research (S.M.), University College London, United Kingdom.
Correspondence to Pilar DOcón, Departamento de Farmacología, Facultad de Farmacia, Universidad de Valencia, Avda Vicent Andres Estelles s/n, Burjassot, 46100 Valencia, Spain. E-mail doconp{at}uv.es
| Abstract |
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Key Words: glyceryl trinitrate nitric oxide mitochondria vascular relaxation NO donors
| Introduction |
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Using confocal microscopy to observe the cells of vessels, we detected endothelium-synthesized NO and compared it with that released by different NO donors and with GTN. Furthermore, the vasodilatatory effects of NO and its consequences for mitochondrial respiration have also been evaluated. By studying these 2 targets of NO,12,13 we identified inconsistencies between the effects of NO, produced both endogenously and pharmacologically, and those obtained with GTN used at clinically relevant concentrations. The nature of these discrepancies suggests that the actions of GTN on the vasculature are indeed unrelated to its bioconversion to NO.
| Materials and Methods |
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Contractility Studies
Aortic rings were suspended in a 5-mL organ bath containing Krebs solution at 37°C. The solution was constantly gassed with 12% O2, 5% CO2, and 83% N2, producing an O2 concentration of 12 to 13x105 mol/L in the bath, which was monitored with a dissolved O2 meter (ISO2; World Precision Instruments, Stevenage, Herts, UK). This level of O2 is similar to that present in the aortic blood.13 Following an equilibration period of 75 to 90 minutes, rings were submaximally (75% to 85% of maximal response) contracted with 106 mol/L phenylephrine (Phe), and the presence of a functional endothelium was confirmed by eliciting a relaxant response (>90%) to 105 mol/L acetylcholine (ACh). Only those vessels exhibiting this response were included in what remained of the experiment.
Following a further equilibration period of 30 to 45 minutes, rings were contracted with a depolarizing solution (6x102 mol/L KCl). After being washed, the vessels returned to the baseline and a further Phe concentration of 106 mol/L was added, giving a sustained contraction equivalent to the response to depolarization. Once such a stable tone was achieved, relaxation-response curves were obtained by adding cumulative concentrations of the NO donors (Z)-1-([2-aminoethyl]-N-[2-ammonioethyl]amino)diazen-1-IM1,2-diolate (DETA-NO) (108 to 105 mol/L), S-nitroso-N-acetylpenicillamine (SNAP) (1010 to 105 mol/L), or 3-morpholinosydnonimine (SIN-1) (1011 to 106 mol/L); and ACh (109 to 105 mol/L) or GTN (1010 to 106 mol/L). In some experiments, the soluble guanylyl cyclase (sGC) inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) (5x106 mol/L), the scavenger of NO and related species oxyhemoglobin (oxyHb) (105 mol/L), or the NO synthase inhibitor N-
-nitro-L-arginine (L-NNA) (104 mol/L) was added before the NO-producing drugs. The adequate concentration (log[M]) for producing 50% relaxation (pEC50) was obtained from a nonlinear regression analysis with Graph Pad Software. The percentage of relaxation obtained with the highest concentration of each agent in the absence (control) or presence of ODQ (5x106 mol/L) or oxyHb (105 mol/L) is represented by Emax.
Confocal Microscopy Imaging of NO Release
NO was visualized with diaminorhodamine-4M (DAR-4M AM), a cell permeable, fluorescent precursor with a convenient profile for NO bioimaging. It exhibits low background fluorescence with longer wavelength excitation, allows detection throughout a wider pH range, and is more photostable than standard fluorochromes that have been used previously for NO imaging.14 Inside the cell, the relatively nonfluorescent DAR-4M AM is converted into its triazole form, DAR-4M T, the fluorescence intensity of which is directly proportional to the concentration of NO, with a detection limit of 7x109 mol/L.14
Aortic rings were incubated in the dark for 60 minutes in a Krebs solution that was constantly gassed (12% O2, 5% CO2, and 83% N2) and that contained DAR-4M AM (2.5x106 mol/L). The vital cell nuclei staining fluorochrome Hoechst 33342 (106 mol/L) was added to this solution after 30 minutes. Thereafter, the rings were mounted in a vertical position on 24x50-mm coverslips, fixed with a grid in Krebs solution, and placed in a heated chamber (37°C, 2 mL; Warner Instrument Corp, Hamden, Conn). Following a 10-minute stabilization period, which was considered basal, cumulative concentrations of DETA-NO (107 to 104 mol/L), SNAP (109 to 105 mol/L), SIN-1 (109 to 106 mol/L), ACh (106 to 104 mol/L), or GTN (109 to 106 mol/L) were added every 10 minutes. In some experiments, before addition of the agents, tissues were preincubated (10 minutes) with L-NNA (104 mol/L). Images were obtained every 2 minutes throughout the entire experiment, which lasted a maximum of 60 minutes. A concentration of DETA-NO (104 mol/L) was added at the end of each experiment to monitor the sensitivity of our system, and, to avoid variability, the response obtained was considered a reference for normalizing the signal elicited in each experimental series. To ensure that the fluorochromes had no influence on the viability of the tissues, parallel experiments were performed in which rings were incubated with these compounds under the same experimental circumstances that confocal analysis and contractility studies were performed. No significant differences were found either in the response to a single concentration of Phe (106 mol/L) or in the concentration-response curves of relaxation to DETA-NO (pEC50: 5.98±0.09 in control versus 5.90±0.08, n=4 and 5, respectively), ACh (pEC50: 7.33±0.10 in control versus 7.23±0.21, n=5), and GTN (8.08±0.06 in control versus 8.40±0.13, n=5 and 6, respectively).
Images were observed in water immersion (x60 magnification) and studied with a Radiance 2100 confocal microscope (Bio-Rad, Hempel Hempstead, UK) using a 405-nm diode laser to excite Hoechst 33342 and a 546-nm He-Ne laser to excite DAR-4M AM. Fluorescence was detected through 440/20 band pass (BP) and 570 long pass (LP) filters for Hoechst 33342 and DAR-4M AM, respectively. DAR-4M AM fluorescence was analyzed (Laserpix software; Bio-Rad) in portions of aortic ring comprising the entire width of the vessel, from the adventitia to the endothelium. Confocal microscope settings were adjusted to produce the optimum signal/noise ratio. The vessel wall exhibited basal red fluorescence, representing the autofluorescence of the elastin fibers, which was deducted from the total quantification of fluorescence in each specific measurement.
Further experiments were performed to exclude the interference on DAR-4M AM fluorescence by GTN or some of its main intermediate metabolites. Different concentrations (109 to 104 mol/L) of GTN, its metabolites 1,2 glyceryl dinitrate (1,2-GDN) and 1,3 glyceryl dinitrate (1,3-GDN), and sodium nitrate (NaNO3) or sodium nitrite (NaNO2) were incubated in the presence of DAR-4M AM (2.5x106 mol/L) in a cell-free Krebs solution. Fluorescence was measured with a Fluoroskan plate reader (Thermo Labsystems) and 104 mol/L DETA-NO was added at the end of each experiment. No modification of the fluorochrome basal fluorescence was obtained after incubation with GTN or any of the compounds tested for 60 minutes. Furthermore, the increase in fluorescence observed after addition of DETA-NO was similar in the presence or absence of these agents (n=4 to 5 experiments; results not shown).
Electrochemical Measurement of O2 Consumption
The aorta of 2 animals (97.65±1.04 mg total wet weight) were cut in rings and placed in gas-tight chambers containing 1 mL of Krebs solution and gently agitated at 37°C. The O2 consumption by the tissue was measured with a Clark-type O2 electrode (Rank Brothers, Bottisham, UK) calibrated with an air-saturated Krebs solution, assuming an O2 concentration of 2x104 mol/L. Experiments were performed in the presence of DETA-NO (108 to 104 mol/L), SNAP (109 to 105 mol/L), SIN-1 (109 to 106 mol/L), ACh (107 to 104 mol/L), or GTN (109 to 106 mol/L). Sodium cyanide (103 mol/L) was used to confirm that O2 consumption was mainly mitochondrial (&95% to 99%). In some experiments, the reversibility of NO-induced inhibition of respiration was assessed by adding oxyHb (105 mol/L) when the concentration of O2 in the chamber was 104 mol/L. Measurements were collected using a data-acquisition device, Duo.18 (World Precision Instruments, Stevenage, UK). A hyperbolic function was used to describe the relationship between O2 concentration and the rate of O2 consumption (VO2).15 The maximal rate of O2 consumption (VO2max) and the apparent O2 affinity Michaelis constant (Km) (106 mol/L) were calculated according to their analogy with the MichaelisMenten constant. The rate of O2 consumption at the interval between 3 to 2x105 mol/L of O2 (similar to conditions during hypoxia16,17) was calculated from the same experiments. To avoid variability, the rate of O2 consumption was expressed as 109 mol O2/min per 106 g protein. Proteins were determined by the BCA protein assay kit (Pierce, Rockford, Ill) using BSA as the standard. In some cases, the viability of the rings was later assessed by confirming that their contractile response to Phe (106 mol/L) and ACh (105 mol/L) did not differ from that of nonmanipulated vessels.
Data Analysis
Values are expressed as mean±SEM. Statistical analysis was performed by 1-way ANOVA followed by the Student t test for unpaired samples (Graph Pad Software). Significance was defined as P<0.05.
Drugs and Solutions
The composition of the Krebs solution was as follows (103 mol/L): 118 NaCl, 4.75 KCl, 1.9 CaCl2, 1.2 MgSO4, 1.2 KH2PO4, 25 NaHCO3, and 10.1 glucose. NaNO3 and NaNO2 were obtained from Panreac (Barcelona, Spain). 1,2-GDN and 1,3-GDN were purchased from LGC Promochem (Barcelona, Spain). Phe, ACh, L-NNA, sodium cyanide, ODQ, meth(a)emoglobin, and Hoechst 33342 were acquired from Sigma Aldrich (St Louis, Mo). DETA-NO was obtained from Alexis (Lausen, Switzerland). A clinically available preparation of GTN was used (Solinitrina from Allmirall Prodesfarma, Barcelona, Spain), and DAR-4M AM was obtained from Calbiochem (San Diego). OxyHb was prepared by reduction of human meth(a)emoglobin with a 10-fold molar excess of sodium dithionite, followed by dialysis against PBS. All drugs were dissolved in ultrapure water, except GTN, DAR-4M AM, and Hoechst 33342, which were dissolved in Krebs solution, and ODQ, which was dissolved in dimethyl sulfoxide (1:5000 [vol/vol]).
| Results |
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Confocal Microscopy Imaging of NO Release
Figure 1A shows representative confocal images of the rat aorta following incubation (60 minutes) with DAR-4M AM and concentration-dependent increases in the red fluorescent signal induced by addition of cumulative concentrations of DETA-NO (107 to 104 mol/L) every 10 minutes. An analysis of the total changes in red fluorescence is presented in Figure 1B. Figure 1 also shows significant and concentration-dependent increases in NO-related DAR-4M AM fluorescence obtained with the other 2 NO donors used, SNAP (109 to 105 mol/L) and SIN-1 (109 to 106 mol/L). Addition of ACh at concentrations that produced maximal vasodilatation (106 to 104 mol/L) increased DAR-4M AM fluorescence in a concentration-dependent manner (Figure 2A). This red fluorescence, although particularly abundant in the endothelial layer, permeated through the entire thickness of the vessel and was prevented by preincubation with L-NNA (104 mol/L) (Figure 2B). Figure 2C summarizes the quantitative analysis of the total changes in red fluorescence. Incubation with L-NNA induced a slight but significant decrease in the signal, which could be interpreted as an inhibition of the basal release of NO. Incubation with GTN (109 to 106 mol/L) did not increase DAR-4M AM fluorescence. Indeed, each increase in the concentration of GTN was accompanied by a significant reduction in red fluorescence, as represented in Figure 3A and quantified in Figure 3B.
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To discard the possibility that such a reduction in the fluorescence was attributable to a direct interference on DAR-4M AM by GTN or any of its main intermediary metabolites, 104 mol/L DETA was added at the end of each experiment and, in all cases, produced a significant increase in the fluorescence observed (Figure 3A). The magnitude of this fluorescence increase in the presence of 104 mol/L GTN was 71.27±17.95% (n=4), and it was similar to that observed when 104 mol/L DETA was added in the absence of GTN or in the presence of 105 mol/L SNAP or 106 mol/L SIN-1 (n=5 to 7 in each case).
Effect on the Rate of O2 Consumption
Table 2 represents the effects of DETA-NO (108 to 105 mol/L), SNAP (109 to 105 mol/L), SIN-1 (109 to 106 mol/L), ACh (107 to 104 mol/L), and GTN (109 to 106 mol/L). DETA-NO, SNAP, SIN-1, and ACh did not modify (data not shown) the VO2max of controls (36.50±1.1x109 mol O2/min/106 g protein) but significantly and concentration-dependently increased the apparent Km for O2 of isolated rings of rat thoracic aorta. Concentrations of GTN (109 to 106 mol/L), which produced maximal relaxation in the aortic rings, neither modified the VO2max nor increased the apparent Km for O2. However, higher concentrations of GTN (105 and 104 mol/L) produced a significant decrease in the VO2max (22.67±1.01 and 12.85±1.12x109 mol O2/min per 106 g protein, respectively) and the apparent Km for O2 (20.5±3.93 and 14.71±6.47, respectively).
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The implication of NO in the effects of DETA-NO, ACh, and GTN on mitochondrial O2 consumption is shown by the representative traces of respiring rings in Figure 4. As suggested by the change in the curve slopes, the rate of O2 consumption was decreased by incubation with concentrations of DETA-NO (105 mol/L) and ACh (105 mol/L), which produced maximal relaxation in the aortic rings. Scavenging of NO by addition of oxyHb reversed the inhibitory effects of both drugs on respiration. This effect was not shared by GTN (106 mol/L). Presence of the sGC inhibitor ODQ (5x106 mol/L) did not modify the inhibitory effect on mitochondrial O2 consumption observed with the 3 agents (data not shown). Figure 5 shows the effects of the various treatments on the O2 consumption rate (VO2) of rat aortic rings in the interval during which O2 concentrations in the bath were similar to those present in hypoxic conditions, between 2 to 3x105 mol/L. Within the same range of concentrations that completely relax precontracted vessels, DETA-NO, SNAP, SIN-1, and ACh reduced O2 consumption concentration dependently, whereas GTN did not modify VO2.
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| Discussion |
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Using confocal microscopy, we performed a new technique for real-time detection of intracellular NO in isolated intact vessels. Incubation of the rat aorta with vasoactive concentrations of DETA-NO, SNAP, and SIN-1 produced concentration-dependent augmentations in DAR-4M AM fluorescence. Similarly, stimulation of the endothelium with maximal vasoactive concentrations of ACh induced an immediate increase in NO-related fluorescence, which was prevented by inhibition of NO synthase. This increase in a NO-related signal was not observed following incubation with GTN. Indeed, there was a small decrease in the intensity of DAR-4M AM fluorescence for which we presently have no explanation.
A similar absence of an NO signal produced by GTN has recently been reported with electron paramagnetic resonance spin trapping in a variety of rodent vessel.11 This technique is also highly sensitive to NO but requires the use of frozen tissue and, therefore, yields single, static measurements. By comparison, our approach allows repetitive real-time assessments of the effects of drugs in a biologically active vessel at various concentrations and throughout a prolonged period of time, thus facilitating a clearer picture of the physiological implications.
The relaxant effects of GTN on the isolated vessels are compatible with an effect mediated by NO. However, our results, considered together with the measurement of NO levels by confocal microscopy, raise the possibility that these effects result from the release of another species that shares with NO the characteristics of being scavenged by oxyHb and of stimulating sGC. This is not a new proposal, and results with other nitrates have shown that they could oxidize oxyHb at a rate that correlates with their vasodilatory potency but not with the release of NO,18,19 thus suggesting the release of a species different from NO.
The idea that the effects of GTN are not a consequence of the release of NO is reinforced further by the analysis of mitochondrial oxygen consumption. The interaction of this mediator with the terminal enzyme of the electron transport chain, cytochrome C oxidase, is emerging as a major pathway through which NO exerts important physiological/pathological functions.13,20 NO reduces the affinity of the enzyme for O2, increasing its Km and, consequently, inhibiting mitochondrial O2 consumption with an intensity that is inversely proportional to the concentration of O2.2124 Our results with DETA-NO, SNAP, SIN-1, and ACh confirm this mechanism of action. They reduced the rate of O2 consumption by the rat aorta in a concentration-dependent manner within the same concentration range that produced NO-mediated vasorelaxations and increased the fluorescent signals in confocal microscopy. Furthermore, they followed a pattern of competitiveness and reversibility previously described for the interaction between NO and cytochrome C oxidase: (1) competitive, because the affinity for O2 is decreased, as shown by the concentration-dependent increase in the Km that occurs without a significant change in the VO2max25,26; and (2) reversible by oxyHb.16,27
The effects of GTN differ and are not compatible with the concept that this compound releases NO, which inhibits mitochondrial O2 consumption in a competitive manner. Clinically used concentrations of GTN, which significantly relax isolated vessels by activation of sGC, do not modify VO2max or the apparent affinity for O2 represented by the Km. Higher, supratherapeutic concentrations of GTN reduce VO2max and decrease the Km in a way that is indicative of a noncompetitive action and probably related to the known GTN capacity to produce reactive oxygen species, such as superoxide and peroxynitrite,2830 that might compromise the function of different mitochondrial enzymes.31,32 The differences between NO donors, ACh, and GTN are particularly evident if analyzed in a hypoxic context, which highlights the inhibition by NO of mitochondrial O2 consumption. With a concentration of O2 between 2 and 3x105 mol/L, equivalent to hypoxic conditions,17 all 3 NO donors and ACh, but not GTN, produce a significant and concentration-dependent inhibition of the mitochondrial O2 consumption. It has recently been suggested that the bioactivation of GTN is mediated by the mitochondrial enzyme aldehyde dehydrogenase.33 Our results do not support the idea that NO is 1 of the species formed as a product of GTN biotransformation, as it would be difficult to explain how such a NO diffuses from the mitochondria to activate the cytosolic sGC without inhibiting mitochondrial complex IV or being detected by confocal microscopy.
We conclude that the biotransformation of GTN does not release free NO. It remains to be investigated whether this leads to the release of another species that directly interacts with sGC in vascular smooth muscle without inhibiting O2 consumption by vascular mitochondria. This variation in the bioactivity of GTN and NO donors is interesting insofar as its therapeutic implications. NO-producing agents produce vasodilatation in concentrations that also significantly inhibit O2 consumption, but GTN does not. GTN is used to improve the blood flow in ischemic tissues, and the fact that this is achieved without any further reduction in the bioenergetic activity of the mitochondria could lie behind its long clinical success.
| Acknowledgments |
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| Footnotes |
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Original received July 5, 2005; resubmission received September 21, 2005; accepted September 29, 2005.
| References |
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2. Chung SJ, Fung HL. Identification of the subcellular site for nitroglycerin metabolism to nitric oxide in bovine coronary smooth muscle cells. J Pharmacol Exp Ther. 1990; 253: 614619.
3. Feelisch M, Kelm M. Biotransformation of organic nitrates to nitric oxide by vascular smooth muscle and endothelial cells. Biochem Biophys Res Commun. 1991; 180: 286293.[CrossRef][Medline] [Order article via Infotrieve]
4. Mulsch A, Bara A, Mordvintcev P, Vanin A, Busse R. Specificity of different organic nitrates to elicit NO formation in rabbit vascular tissues and organs in vivo. Br J Pharmacol. 1995; 116: 27432749.[Medline] [Order article via Infotrieve]
5. Agvald P, Adding LC, Artlich A, Persson MG, Gustafsson LE. Mechanisms of nitric oxide generation from nitroglycerin and endogenous sources during hypoxia in vivo. Br J Pharmacol. 2002; 135: 373382.[CrossRef][Medline] [Order article via Infotrieve]
6. Kozlov AV, Dietrich B, Nohl H. Various intracellular compartments cooperate in the release of nitric oxide from glycerol trinitrate in liver. Br J Pharmacol. 2003; 139: 989997.[CrossRef][Medline] [Order article via Infotrieve]
7. Fung HL. Biochemical mechanism of nitroglycerin action and tolerance:is this old mystery solved? Annu Rev Pharmacol Toxicol. 2004; 44: 6785.[CrossRef][Medline] [Order article via Infotrieve]
8. Kearney MF, Brien JF, Marks GS, Lei H, Nakatsu K. Thiol agents separate nitric oxide formation from vasodilation induced by glyceryl trinitrate. Drug Metab Dispos. 1998; 26: 547551.
9. Hussain AS, Crispino NH, McLaughlin BE, Brien JF, Marks GS, Nakatsu K. Glyceryl trinitrate-induced vasodilation is inhibited by ultraviolet irradiation despite enhanced nitric oxide generation: evidence for formation of a nitric oxide conjugate. J Pharmacol Exp Ther. 1999; 289: 895900.
10. Artz JD, Toader V, Zavorin SI, Bennett BM, Thatcher GR. In vitro activation of soluble guanylyl cyclase and nitric oxide release: a comparison of NO donors and NO mimetics. Biochemistry. 2001; 40: 92569264.[CrossRef][Medline] [Order article via Infotrieve]
11. Kleschyov AL, Oelze M, Daiber A, Huang Y, Mollnau H, Schulz E, Sydow K, Fichtlscherer B, Mulsch A, Munzel T. Does nitric oxide mediate the vasodilator activity of nitroglycerin? Circ Res. 2003; 93: e104e112.[CrossRef][Medline] [Order article via Infotrieve]
12. Knowles RG, Moncada S. Nitric oxide as a signal in blood vessels. Trends Biochem Sci. 1992; 17: 399402.[CrossRef][Medline] [Order article via Infotrieve]
13. Moncada S, Erusalimsky JD. Does nitric oxide modulate mitochondrial energy generation and apoptosis? Nat Rev Mol Cell Biol. 2002; 3: 214220.[CrossRef][Medline] [Order article via Infotrieve]
14. Kojima H, Hirotani M, Nakatsubo N, Kikuchi K, Urano Y, Higuchi T, Hirata Y, Nagano T. Bioimaging of nitric oxide with fluorescent indicators based on the rhodamine chromophore. Anal Chem. 2001; 73: 19671973.[Medline] [Order article via Infotrieve]
15. Palacios-Callender M, Quintero M, Hollis VS, Springett RJ, Moncada S. Endogenous NO regulates superoxide production at low oxygen concentrations by modifying the redox state of cytochrome c oxidase. Proc Natl Acad Sci U S A. 2004; 101: 76307635.
16. Mateo J, Garcia-Lecea M, Cadenas S, Hernandez C, Moncada S. Regulation of hypoxia-inducible factor-1alpha by nitric oxide through mitochondria-dependent and -independent pathways. Biochem J. 2003; 376: 537544.[CrossRef][Medline] [Order article via Infotrieve]
17. Hagen T, Taylor CT, Lam F, Moncada S. Redistribution of intracellular oxygen in hypoxia by nitric oxide: effect on HIF1alpha. Science. 2003; 302: 19751978.
18. Artz JD, Thatcher GR. NO release from NO donors and nitrovasodilators: comparisons between oxyhemoglobin and potentiometric assays. Chem Res Toxicol. 1998; 11: 13931397.[CrossRef][Medline] [Order article via Infotrieve]
19. Thatcher GR, Nicolescu AC, Bennett BM, Toader V. Nitrates and NO release: contemporary aspects in biological and medicinal chemistry. Free Radic Biol Med. 2004; 37: 11221143.[CrossRef][Medline] [Order article via Infotrieve]
20. Cooper CE, Davies NA. Effects of nitric oxide and peroxynitrite on the cytochrome oxidase K(m) for oxygen: implications for mitochondrial pathology. Biochim Biophys Acta. 2000; 1459: 390396.[Medline] [Order article via Infotrieve]
21. Cleeter MW, Cooper JM, Darley-Usmar VM, Moncada S, Schapira AH. Reversible inhibition of cytochrome c oxidase, the terminal enzyme of the mitochondrial respiratory chain, by nitric oxide. Implications for neurodegenerative diseases. FEBS Lett. 1994; 345: 5054.[CrossRef][Medline] [Order article via Infotrieve]
22. Brown GC, Cooper CE. Nanomolar concentrations of nitric oxide reversibly inhibit synaptosomal respiration by competing with oxygen at cytochrome oxidase. FEBS Lett. 1994; 356: 295298.[CrossRef][Medline] [Order article via Infotrieve]
23. Loke KE, Laycock SK, Mital S, Wolin MS, Bernstein R, Oz M, Addonizio L, Kaley G, Hintze TH. Nitric oxide modulates mitochondrial respiration in failing human heart. Circulation. 1999; 100: 12911297.
24. Brookes PS, Kraus DW, Shiva S, Doeller JE, Barone MC, Patel RP, Lancaster JR Jr, Darley-Usmar V. Control of mitochondrial respiration by NO*, effects of low oxygen and respiratory state. J Biol Chem. 2003; 278: 3160331609.
25. Schweizer M, Richter C. Nitric oxide potently and reversibly deenergizes mitochondria at low oxygen tension. Biochem Biophys Res Commun. 1994; 204: 169175.[CrossRef][Medline] [Order article via Infotrieve]
26. Clementi E, Brown GC, Foxwell N, Moncada S. On the mechanism by which vascular endothelial cells regulate their oxygen consumption. Proc Natl Acad Sci U S A. 1999; 96: 15591562.
27. Borutaite V, Matthias A, Harris H, Moncada S, Brown GC. Reversible inhibition of cellular respiration by nitric oxide in vascular inflammation. Am J Physiol Heart Circ Physiol. 2001; 281: H2256H2260.
28. Sydow K, Daiber A, Oelze M, Chen Z, August M, Wendt M, Ullrich V, Mulsch A, Schulz E, Keaney JF Jr, Stamler JS, Munzel T. Central role of mitochondrial aldehyde dehydrogenase and reactive oxygen species in nitroglycerin tolerance and cross-tolerance. J Clin Invest. 2004; 113: 482489.[CrossRef][Medline] [Order article via Infotrieve]
29. Dikalov S, Fink B, Skatchkov M, Stalleicken D, Bassenge E. Formation of reactive oxygen species by pentaerithrityltetranitrate and glyceryl trinitrate in vitro and development of nitrate tolerance. J Pharmacol Exp Ther. 1998; 286: 938944.
30. Mihm MJ, Coyle CM, Jing L, Bauer JA. Vascular peroxynitrite formation during organic nitrate tolerance. J Pharmacol Exp Ther. 1999; 291: 194198.
31. Brown GC. Regulation of mitochondrial respiration by nitric oxide inhibition of cytochrome c oxidase. Biochim Biophys Acta. 2001; 1504: 4657.[Medline] [Order article via Infotrieve]
32. Parker JD. Nitrate tolerance, oxidative stress, and mitochondrial function: another worrisome chapter on the effects of organic nitrates. J Clin Invest. 2004; 113: 352354.[CrossRef][Medline] [Order article via Infotrieve]
33. Chen Z, Zhang J, Stamler S. Identification of the enzymatic mechanism of nitroglycerin bioactivation. Proc Natl Acad Sci U S A. 2002; 99: 83068311.
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