FASEB J. Cell Migration Consortium
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by CUZZOCREA, S.
Right arrow Articles by SALVEMINI, D.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by CUZZOCREA, S.
Right arrow Articles by SALVEMINI, D.
(The FASEB Journal. 2004;18:94-101.)
© 2004 FASEB

Superoxide: a key player in hypertension

SALVATORE CUZZOCREA, EMANUELA MAZZON*, LAURA DUGO, ROSANNA DI PAOLA, ACHILLE P. CAPUTI and D. SALVEMINI{dagger},1

Institute of Pharmacology, University of Messina;
* Department of Biomorphology, School of Medicine, University of Messina, Italy; and
{dagger} Department of Biological and Pharmacological Research, MetaPhore Pharmaceuticals, St. Louis, Missouri, USA

1 Correspondence: MetaPhore Pharmaceuticals, 1910 Innerbelt Business Center Dr., St. Louis, MO 63114, USA. E-mail: dsalvemini{at}metaphore.com


   ABSTRACT
TOP
 ABSTRACT
INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
Superoxide is increased in the vessel wall of spontaneously hypertensive rats (SHR) where, if "blocked," potentiates endothelium-dependent vasodilation. The purpose of this study was to determine the role of superoxide anion in hypertension and its interaction with nitric oxide (NO). For this purpose we used a low molecular weight synthetic superoxide dismutase mimetic (M40403), known to remove selectively superoxide anion. Baseline mean arterial pressure (MAP) was significantly elevated in the SHR compared with its normal counterpart, Wistar Kyoto (WKY). M40403 at a dose (2 mg·kg–1·h–1), which had no effect in the WKY, significantly decreased MAP in SHR rats. To determine whether superoxide anion increases MAP by inactivating NO, NO synthesis was blocked with NG nitro-arginine methyl ester (L-NAME, 3 mg/kg i.v.), a nonselective nitric oxide synthase inhibitor. L-NAME (3 mg/kg, i.v) blocked the anti-hypertensive effect of M40403 (2 mg/kg over 30 min). When used at a dose that yielded similar increases in MAP, norepinephrine (2.1 µg/kg) failed to alter the anti-hypertensive effects of M40403 in the SHR. To investigate whether the anti-hypertensive effect of M40403 was associated with an improvement of the alterations in vascular reactivity, a separate group of experiments was carried out ex vivo. Endothelium-dependent vasorelaxation to acetylcholine (10 nM–10 µM), an index of endothelial function, was reduced in aortic rings taken from SHR rats when compared with WKY rats. In vivo treatment with M40403 caused an improvement of the degree of the endothelial dysfunction in SHR rats. Furthermore, immunohistochemical analysis for nitrotyrosine (the product formed from the interaction of nitric oxide with superoxide) revealed a positive staining in aorta from SHR rats. The degree of staining for nitrotyrosine was markedly reduced in tissue sections obtained from SHR rats treated with M40403. Our data suggest that overt production of superoxide in SHR couples with nitric oxide, reducing its function and leading to a loss of blood vessel tone and hypertension. Another important effect appears to be at the level of endothelial cellular integrity, where by interacting with nitric oxide, superoxide anion forms peroxynitrite and subsequent endothelial cell dysfunction. By removing superoxide, M40403 restores blood pressure to near-to-normal values.—Cuzzocrea, S., Mazzon, E., Dugo, L., Di Paola, R., Caputi, A. P., Salvemini, D. Superoxide: a key player in hypertension.


Key Words: superoxide dismutase • M40403 • F2-isoprostane


   INTRODUCTION
TOP
 ABSTRACT
 INTRODUCTION
MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
AN EXAGGERATED PRODUCTION of superoxide (O2–) by the vascular wall has been observed in different animal models of hypertension, including spontaneously hypertensive rats (SHR) (1–3). It was recently demonstrated in cultured rat vascular smooth muscle cells (4) and in intact aortas of rats made hypertensive by angiotensin II infusion that angiotensin II may also stimulate superoxide generation by increasing the activity of the enzyme NAD(P)H oxidase (5) . Therefore, in the majority of cases the source of O2– is uncertain, although an involvement of endothelial nitric oxide synthase (NOS) (6 , 7) and xanthine-oxidase (8 , 9) has been suggested. Superoxide is also generated by the enzyme NOS. In fact, purified rat brain NOS (NOS I) has been shown to produce O2–, and this is inhibited by N{omega}-nitro-L-arginine methyl ester (L-NAME) (10) . A recent study has suggested that NOS III is a source of O2– production in human umbilical vein endothelial cells stimulated with native low density lipoprotein, as it can be inhibited by L-NAME (11) . The reason NOS switches from generating beneficial NO to generating harmful O2– remains unclear. Growing evidence supports the possibility that increased oxidative inactivation of nitric oxide (NO) by an excess of superoxide may account for the decrease in available NO and endothelial dysfunction seen in spontaneously hypertensive rats (11 12 13 14) . Thus, endothelial dysfunction and a relative deficiency in NO may be associated with hypertension in humans (15 16) and in some models of experimental hypertension (17 , 18) .

It is now well established that endogenous NO from the endothelial isoform plays an important role in regulating blood pressure (19 20 21) . Thus, inhibition of endogenous nitric oxide by NOS inhibitors causes a profound increase in blood pressure (22 , 23) . Endothelial cells from spontaneously hypertensive stroke-prone rat produce less NO than cells from the WKY, the normotensive reference strain (24) . Using the spontaneously hypertensive stroke-prone rat as a model of genetic hypertension, an attenuation of functional basal NO has been shown despite an increase in endothelial NOS activity (25) . Taken together, these observations support the hypothesis that a NO deficiency could contribute to the elevated arterial pressure in spontaneously hypertensive stroke-prone rats. Such a hypothesis has clinical relevance since several investigators have in fact reported a deficit in endothelial NO release in the brachial (15 ,, 20 , 21) and coronary (26) circulations of human essential hypertension. It should be noted, however, that two reports (27 , 28) failed to observe this deficit. It has been proposed that in hypertension the excessive release of superoxide scavenges NO as it is produced, leading to the development of increased blood pressure (12 , 29) . This led us to conclude that O2– is released by the endothelial cell, along with NO inhibiting the action of this physiological vasodilator (30) and forming peroxynitrite (ONOO–), a potent cytotoxic and proinflammatory mediator (31 32 33 34) . Recent studies have demonstrated that peroxynitrite, oxidizing arachidonic acid to form F2-isoprostanes which exert potent vasoconstrictor and anti-natriuretic effects (35) . The postulation that peroxynitrite leads to a vasoconstrictor effect through the synthesis of isoprostane should be tempered by the discovery of parallel biochemical effects, the role of which remains undefined in the regulation of vascular tone. Some evidence indicates that peroxynitrite may not follow the oxidative pathway through arachidonic acid with the production of isoprostane, but could combine with thiol groups of glutathione to produce S-nitroglutathione (36) . This compound could subsequently degenerate to produce NO and vasodilatation (37) . This effect has been postulated to explain the prolonged vasodepressor effect elicited by peroxynitrite in pulmonary arteries (37) . Although a substantial body of evidence demonstrates the development of endothelial dysfunction in various pathophysiological states and a link between free radicals, oxidants, and endothelial injury has been established, the cellular mechanisms leading to injury and the importance of endogenous protective factors limiting the endothelial dysfunction, are poorly defined. Recently, Villa and co-workers directly demonstrated in isolated perfused hearts that infusion of authentic peroxynitrite results in an impairment of the endothelium-dependent relaxations (38) . Limited data are available as to the potential mechanisms leading to the development of peroxynitrite-induced endothelium-dependent relaxations. In cultured bovine endothelial cells, exposure to peroxynitrite caused a reduced cellular ability to mobilize calcium in response to endothelium-dependent vasodilator agonists (39) , in agreement with published data demonstrating inactivation of calcium pumps in response to peroxynitrite exposure (40) .

The goals of our current investigation were to study the role of superoxide in hypertension. For this purpose, we have used M40403, a stable, low molecular weight, manganese-containing SOD mimetic. M40403 removes superoxide selectively without interfering with other important molecules such as NO (41 , 42) . M40403 has been shown to possess anti-inflammatory properties (43 44 45 46) and to exert protective effects in ischemia and reperfusion injury (45 , 47 , 48) . Our results demonstrate that in a well-characterized experimental model of essential hypertension in rats, M40403 restores the increased blood pressure to near-normal values most likely by preserving vasodilatory activity of NO and inhibiting the formation of peroxynitrite thus attenuating endothelial cell dysfunction.


   MATERIALS AND METHODS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
RESULTS
 DISCUSSION
 REFERENCES
 
Animals
Groups of male SHR and WKY (200–300 g; Charles River, Milan, Italy) were fed ad libitum tap water and standard chow. Protocols were approved and performed according to the Guide for the Care and Use of Laboratory Animals of the ECC. Animal care was in compliance with Italian regulations on protection of animals used for experimental and other scientific purposes (D.M. 116192) as well as with the EEC regulations (O.J. of E.C. L 358/1 12/18/1986)

Experimental procedures
WKY and SHR were anesthetized with sodium pentobarbital (45 mg/kg, i.p.) and maintained at 37°C on a servo-controlled, heated rodent operating table. A tracheotomy was performed with polyethylene PE-240 tubing, and the left jugular vein and carotid artery were cannulated with PE-50 tubing. Intravenous (i.v.) infusion of 1% albumin dissolved in 0.154 mol/L NaCl solution was infused at 2 mL/h IV to maintain an euvolemic state. MAP was continuously recorded from the carotid artery using a pressure transducer and MACLab data acquisition program. After 60 min of equilibration, there was a basal period for measurement of MAP over 60 min. Hemodynamic parameters were measured under basal conditions and during i.v. infusion of M40403 at 2 mg·kg–1·h–1 for 6 h.

In a separate set of experiments to determine whether superoxide increases MAP through interaction with the NO pathway, the MAP response to M40403 was determined in anesthetized SHR and in SHR pretreated with the NO synthase inhibitor L-NAME (3 mg/kg, i.v.). To ensure that any change in the MAP response to M40403 in SHR during L-NAME administration was not due solely to an increase in MAP and vascular tone, independent of NO, the protocol was repeated in SHR infused with a dose of norepinephrine (2.1 µg/kg), which caused an increase in MAP similar to the one evoked by L-NAME (3 mg/kg). In all rats, MAP was measured under basal conditions; during 20 min of pretreatment with either saline vehicle, L-NAME, or norepinephrine; 30 min after 20 min of constant infusion of M40403 (2 mg/kg). The dose of 2 mg/kg chosen for M40403 was taken from a previous study (45). The number of rats for each experimental group was 10 (n=10). For the in vitro and ex vivo study, the animals were scarified at the specified time by inhalation of CO2.

Longer term effect of M40403 on MAP
In a separate set of experiments, animals were anesthetized with sodium pentobarbital (45 mg/kg i.p.). The femoral artery was cannulated with PE-50 tubing. The catheter was then sealed with a straight pin and routed subcutaneously to the nape of the neck and through a leather harness fastened around the forequarters of the rat. The animals were allowed to recover for 3 days before experiments were performed. Immediately before the experiments, the catheter was connected to a pressure transducer and a stable baseline of mean arterial blood pressure (MAP) was recorded for 20 min. The next day M40403 was administered at 2 mg/kg i.p. for 7 days. The MAP of freely moving rats was then recorded during the 7 days of treatment and for 4 days thereafter.

Measurement of vascular reactivity ex vivo
Thoracic descending aortas were collected from anesthetized WKY and SHR after 6 h of i.v. infusion of M40403 (2 mg·kg–1·h–1) or vehicle. Thoracic descending aortas were immediately excised, cut into rings, and mounted in organ baths (5 mL) filled with warmer (37°C) oxygenated (95% O2/5% CO2) Krebs’ solution (pH 7.4) consisting (in mM) of NaCl, 118; KCl, 4.7; KH2PO4, 1.2; CaCl2, 2.5; MgSO4, 1.2; NaHCO3, 25; glucose, 11.7 in the presence of indomethacin (10 µM). Isometric force was measured with isometric transducers (Kent Scientific Corp., Torrington, CT, USA), digitized using a Maclab A/D converter (AD Instruments, Colorado Springs, CO, USA), then stored and displayed on a Macintosh personal computer. A tension of 1 g was applied and the rings were equilibrated for 60 min. Fresh Krebs’ solution was provided at 15 min intervals. Endothelium-dependent relaxations were evaluated with concentration-response curves to acetylcholine (10 nM to 10 µM) in aortic rings precontracted with noradrenaline (1 µM). Relaxation was calculated as % of precontractile vascular tone.

Immunohistochemical localization of nitrotyrosine
Tyrosine nitration was detected as described previously (49) in thoracic descending aortas by immunohistochemistry. Tissues were fixed in 10% buffered formalin and 8 µm sections were prepared from paraffin-embedded tissues. After deparaffinization, endogenous peroxidase was quenched with 0.3% H2O2 in 60% methanol for 30 min. The sections were permeabilized with 0.1% Triton X-100 in phosphate-buffered saline (PBS) for 20 min. Nonspecific adsorption was minimized by incubating the section in 2% normal goat serum in PBS for 20 min. Endogenous biotin or avidin binding sites were blocked by sequential incubation for 15 min with avidin and biotin (DBA, Milan, Italy). Sections were then incubated overnight with a 1:1000 dilution of primary anti-nitrotyrosine antibody (DBA) or with control solutions. Controls included buffer alone or nonspecific purified rabbit IgG. Specific labeling was detected with a biotin-conjugated goat anti-rabbit IgG and avidin-biotin peroxidase complex (DBA).

Statistics
All values shown are mean ± SE. ANOVA was used to determine statistical significance in groups 1 and 2. Student's t test was used to determine significance in groups 3 and 4, where the comparison was limited to two observations. P < 0.05 was considered statistically significant.


   RESULTS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
DISCUSSION
 REFERENCES
 
Effect of constant M40403 infusion on MAP
M40403 (2 mg·kg–1·h–1, Fig. 1 ) significantly attenuated MAP in SHR rats but not in the WKY, an effect blocked by the nonselective NOS inhibitor L-NAME (Fig. 2 ; ref 51 ) (3 mg/kg i.v.), but not by norepinephrine (2.1 µg/kg), at a dose that caused an increase in MAP similar to that obtained with L-NAME (Fig. 2) .



View larger version (23K):
[in this window]
[in a new window]
  		Figure 1. Mean arterial blood pressure (MAP) during baseline conditions (basal) and i.v. infusion of M40403 (2 mg· kg–1·h–1) in anesthetized WKY and SHR rats. *P < 0.05 vs. WKY, °P < 0.05 vs. vehicle-treated SHR.



View larger version (20K):
[in this window]
[in a new window]
  		Figure 2. Change in mean arterial blood pressure (MAP) after 30 min of i.v. infusion of M40403 (2 mg·kg–1·h–1) in SHR pretreated with isotonic saline vehicle, the NO synthase inhibitor L-NAME (3 mg/kg), or norepinephrine (NE 2.1 µg/kg) *P < 0.05 vs. WKY, °P < 0.05 vs. vehicle-treated SHR. °°P < 0.05 vs. norepinephrine pretreated SHR.

Longer term effect of M40403 on MAP
Figure 3 depicts the change in MAP after 4 days of M40403 administration in SHR rats. Baseline MAP was significantly elevated in SHR vs. WKY. After 4 days of M40403 (2 mg/kg i.p.), there was no change in MAP of the WKY (data not shown). In contrast, M40403 treatment significantly reduced MAP of the SHR. This significant hypertensive effect of M4003 was also present 4 days after treatment ended (Fig. 3) .



View larger version (26K):
[in this window]
[in a new window]
  		Figure 3. Longer term effect of M40403 on MAP. M40403 daily treatment (2 mg/kg i.p.) significantly reduced MAP of the SHR. This significant hypertensive effect of M4003 was present 4 days after treatment ended. *P < 0.05 vs. baseline.

Vascular reactivity
To investigate whether the hypotensive effect of M40403 treatment in SHR rats was associated with an improvement of the alterations in vascular reactivity, a separate group of experiments was carried out ex vivo. Endothelium-dependent vasorelaxation to Ach (10 nM–10 µM) was reduced in aortic rings taken from SHR rats compared with WKY rats (Fig. 4 ). In vivo treatment with M40403 caused an improvement in the degree of endothelial dysfunction in SHR rats (Fig. 4) . Treatment with M40403 did not alter dilatations to the acetylcholine response in aortic rings from WKY rats (Fig. 4) .



View larger version (22K):
[in this window]
[in a new window]
  		Figure 4. Effect of i.v. infusion of M40403 (2 mg·kg–1·h–1) on relaxant responses to acetylcholine activity (10 nM–10 µM) in thoracic aortic rings from WKY or SHR. Data represent means ± SE of n= 9 rings. *P < 0.05 represents a significant impairment of the relaxations in aortic rings from vehicle-treated SHR rats. °P < 0.05 represents significant protection by the treatment.

Nitrotyrosine formation in vascular rings
Aortic rings were obtained from SHR rats, and the presence of nitrotyrosine as marker for peroxynitrite formation was examined. Staining was absent in tissues from WKY rats (Fig. 5 A). Immunohistochemical analysis using a specific anti-nitrotyrosine antibody revealed a positive nitrotyrosine staining in aortas from SHR rats (Fig. 5B ). M40403 treatment for 7 days (2 mg/kg) reduced the degree of immunostaining for nitrotyrosine (Fig. 5C ) in the aorta from SHR.



View larger version (56K):
[in this window]
[in a new window]
  		Figure 5. Immunohistochemical localization of nitrotyrosine in the rat thoracic aorta. Staining was negligible in aorta from WKY rats (A). Significant nitrotyrosine staining was observed in aorta section from SHR rats (B). M40403 treatment for 7 days (2 mg/kg) reduced the degree of nitrotyrosine staining (C) Original magnification: x250. Figure is representative of at least 3 experiments performed on different experimental days. M: media; A: aventizia; I: intima.


   DISCUSSION
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
REFERENCES
 
It is well known that the renin-angiotensin system plays a major role in hypertension. The mechanism of renin-angiotensin system-induced hypertension has generally been attributed to the vasoconstrictor effects of angiotensin II and the mineralocorticoid effects of aldosterone. However, recent work has revealed an additional potential mechanism. Angiotensin II has been shown to stimulate superoxide generation by increasing the activity of the enzyme NAD(P)H cytochrome P-450 oxidoreductase, more commonly termed NAD(P)H oxidase, in cultured rat vascular smooth muscle cells (4) and in intact aortas of rats made hypertensive by angiotensin II infusion (5) . This seems to be a fairly specific effect, since rats made hypertensive to a similar degree by infusion of norepinephrine showed no increase in NAD(P)H oxidase activity (5) . Blood pressure and vascular reactivity could be restored by exogenous liposome-encapsulated SOD in the angiotensin II hypertensive rats, but not the norepinephrine-induced hypertensive rats (49) . This further implicates O2– in hypertension associated with high angiotensin II states (49) .

Superoxide has been implicated in other models of experimental hypertension. Grunfeld et al. (12) used lucigenin chemiluminescence to demonstrate that in aortas of the stroke-prone spontaneously hypertensive rat model of genetic hypertension, excess O2– accounts for the reduced bioavailability of NO detected by their porphyritic microsensor. The following year, Tschudi et al. (13) used an adapted porphyritic microsensor to confirm normal NO production but increased decomposition by O2– in the mesenteric resistance vessels of SHRSP. Other studies have substantiated the observations that release of NO from eNOS is greater in the SHR than WKY (24) , but bioavailability is reduced in the former (50) . Superoxide generation in aortas from SHRSP, but not from WKY, has been shown to be reduced by a NO synthase inhibitor, suggesting that endothelial NOS (NOS III) may be the enzyme responsible (7) .

M40403, a membrane-permeable SOD mimetic, normalized blood pressure in SHR. Because the anti-hypertensive response was blocked by inhibition of NOS, the effect must depend on NO. The antioxidant Tempol, which removes superoxide (and other species such as hydrogen peroxide and peroxynitrite), has been shown to reduce blood pressure in SHR rats, further supporting a role for superoxide in the disease (51) . Previous studies investigating the short-term actions of superoxide on blood pressure in SHR demonstrated that a bolus injection of a xanthine oxidase inhibitor to block the formation of O2– from xanthine (52) or use of the CuZn SOD enzyme (8) acutely decreased MAP in the SHR; however, results for WKY were not reported.

In our study we show that removal of superoxide by M40403 decreases blood pressure to near-to-control values, presumably because it protects deactivation of endogenously released NO (as evidenced by loss of the effects of M40403 by L-NAME and by the findings that M40403 restores endothelium-dependent vasorelaxations to Ach in SHR but not WKY). The role of NO in hypertensive states has been documented. It is apparent that a reduction in the bioavailability of NO leads to an increase in blood pressure. Thus, several studies have shown that blockade of NO causes hypertension in animal models (53 , 54) and humans (55) . SHR mice have reduced endothelium-dependent vasodilation in several vascular beds, including the aorta, that has been ascribed in part to increased NO degradation by O2–. Tschudi et al. (13) demonstrated that the defective release of NO from mesenteric arterioles of SHR could be normalized after SOD. Grunfeld et al. (12) showed that endothelial cells cultured from aorta of stroke-prone SHR had an apparent decrease in NO release that was fully reversed by SOD, and therefore presumably represented enhanced NO degradation by O2–. In their study, blockade of SOD enhanced endothelium-dependent relaxation of the aorta of SHR to a greater extent than in WKY. In the present study we observed in aortic rings from SHR animals an impairment of endothelium-dependent dilatation compared with WHY rats, as evidenced by a reduced relaxant effect of the acetylcholine. In vivo treatment with M40403 improved the degree of endothelial dysfunction in SHR rats.

There are several possible mechanisms by which NO mediates the anti-hypertensive actions of M40403. A possible and most likely mechanism by which M40403 reduces hypertension is in reducing peroxynitrite formation by simply removing superoxide before it reacts with NO. Scavenging of O2– increases the half-life of NO. Gryglewski et al. (30) showed that O2– is important in the breakdown of NO to peroxynitrite, and Rubanyi and Vanhoutte (56) demonstrated that O2– inactivates NO in coronary artery rings This has two important consequences: sparing of beneficial NO, and the removal of toxic peroxynitrite. Peroxynitrite has been implicated in vascular dysfunction (57 , 58) . Peroxynitrite nitrates tyrosine residues in proteins; nitrotyrosine formation (as detected by immunofluorescence) has been used as a marker of endogenous formation of peroxynitrite (59) or as an indicator of "increased nitrosative stress" (60) . We have found that nitrotyrosine is indeed present in aorta sections taken from SHR rats (but not in sections from WKY rats) and that M40403 reduced the staining in these tissues. Based on these findings, we may conclude that the hypertension observed in SHR rats evoked (at least in part) a superoxide-driven peroxynitrite formation that, in turn, was responsible for the formation of nitrotyrosine.

There are several possible sources of O2–, including xanthine oxidase, NADPH oxidase, incomplete electron transport, and NOS (61) . The source of O2– in our study remains unclear. As a result of the powerful interaction between O2– and NO, M40403 may prolong the half-life of NO, allowing it to exert a more powerful vasodilatory action. Finally, by blocking the formation of peroxynitrite, M40403 may inhibit the production of vasoconstrictor endoperoxides that are stimulated by peroxynitrite in macrophages (62) .

In summary, M40403 significantly reduces endothelium dysfunction and MAP in SHR to a greater extent than in WKY. The antihypertensive actions of M40403 are dependent on NO.

Received for publication May 6, 2003. Accepted for publication September 8, 2003.


   REFERENCES
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 

  1. Bouloumie, A., Bauersachs, J., Linz, W., Scholkens, B. A., Wiemer, G., Fleming, I., Busse, R. () Endothelial dysfunction coincides with an enhanced nitric oxide synthase expression and superoxide anion production. Hypertension 30,934-941
  2. Suzuki, H., Swei, A., Zweifach, B. W., Schmid-Schonbein, G. W. (1995) In vivo evidence for microvascular oxidative stress in spontaneously hypertensive rats. Hypertension 25,1083-1089[Abstract/Free Full Text]
  3. Dohi, Y., Theil, M., Buhler, F. R., Luscher, T. F. (1995) Activation of the endothelial L-arginine pathway in pressurized mesenteric resistance arteries: effect of age and hypertension. Hypertension 15,170-175
  4. Griendling, K. K., Minieri, D., Ollernshaw, D., Alexander, R. W. (1994) Angiotensin II stimulates NADH and NADPH-oxidase activity in cultured vascular smooth muscle cells. Circ. Res. 74,1141-1148[Abstract/Free Full Text]
  5. Rajagoplan, S., Kurz, S., Munzel, T., Tarpey, M., Freeman, B. A., Griendling, K. K., Harrison, D. G. (1996) Angiotensin II-mediated hypertension in the rat increases vascular superoxide production via membrane NADH/NADPH oxidase activation: contribution to alteration of vasomotor tone. J. Clin. Invest. 97,1916-1923[Medline]
  6. Cosentino, F., Patton, S., d'Uscio, L. V., Werner, E. R., Werner-Felmayer, G., Moreau, P., Malinski, T., Luscher, T. F. (1998) Tetrahydrobiopterin alters superoxide and nitric oxide release in prehypertensive rats. J. Clin. Invest. 101,1530-1537[Medline]
  7. Kerr, S., Brosnan, M. J., McIntyre, M., Reid, J. L., Dominiczak, A. F., Hamilton, C. A. (1999) Superoxide anion production is increased in a model of genetic hypertension: role of endothelium. Hypertension 33,1353-1358[Abstract/Free Full Text]
  8. Nazakono, Y., Watanabe, N., Matsuno, K., Sasaki, J., Sato, T., Inoue, M. (1991) Does superoxide underlie the pathogenesis of hypertension?. Proc. Natl. Acad. Sci. USA 88,10045-10048[Abstract/Free Full Text]
  9. Miyamoto, Y., Akaike, T., Yoshida, M., Goto, S., Horie, H., Maeda, H. (1991) Potentiation of nitric oxide-mediated vasorelaxation by xanthine oxidase inhibitors. Proc. Soc. Exp. Biol. Med. 21,366-373
  10. Boveris, A., Chance, B. (1973) The mitochondrial generation of hydrogen peroxide. General properties and effect of hyperbaric oxygen. Biochem. J. 134,707-716[Medline]
  11. Pritchard, K. A., Jr, Groszek, L., Smalley, D. M., Sessa, W. C., Wu, M., Villalon, P., Wolin, M. S., Stemerman, M. B. (1995) Native low density lipoprotein increases endothelial cell nitric oxide synthase generation of superoxide anion. Circ. Res. 77,510-518[Abstract/Free Full Text]
  12. Grunfeld, S., Hamilton, C. A., Mesaros, S., McClain, S. W., Dominiczak, A. F., Bohr, D. F., Malinski, T. (1995) Role of superoxide in depressed nitric oxide production by the endothelium of genetically hypertensive rats. Hypertension 26,854-857[Abstract/Free Full Text]
  13. Tschudi, M., Mesaros, S., Luscher, T. F., Malinski, T. (1996) Direct in situ measurement of nitric oxide in mesenteric arteries. Hypertension 27,32-35[Abstract/Free Full Text]
  14. Schnackenberg, C. G., Welch, W. J., Wilcox, C. S. (1998) Normalization of blood pressure and renal vascular resistance in SHR with membrane permeable superoxide dismutase mimetic: role of nitric oxide. Hypertension 32,59-64[Abstract/Free Full Text]
  15. Linder, L., Kiowski, W., Buhler, F. R., Luscher, T. F. (1990) Indirect evidence for release of endothelium derived relaxing factor in human forearm circulation in vivo: blunted response in essential hypertension. Circulation 81,1762-1767[Abstract/Free Full Text]
  16. Taddei, S., Virdis, A., Mattei, P., Salvetti, A. (1993) Vasodilation to acetylcholine in primary and secondary forms of human hypertension. Hypertension 21,929-933[Abstract/Free Full Text]
  17. Rees, D., Ben-Ishay, D., Moncada, S. (1996) Nitric oxide and the regulation of blood pressure in the hypertension prone and hypertension resistant Sabra rat. Hypertension 28,367-371[Abstract/Free Full Text]
  18. Maruyama, J., Maruyama, K. (1994) Impaired nitric oxide dependent responses and their recovery in hypertensive pulmonary arteries of rats. Am. J. Physiol. 266,H2476-H2488
  19. Palmer, R. M., Ferrige, A. G., Moncada, S. (1987) Nitric oxide release accounts for the biological activity of endothelium-derived relaxing factor. Nature (London) 327,524-526[CrossRef][Medline]
  20. Vallance, P., Collier, J., Moncada, S. (1989) Effects of endothelium-derived nitric oxide on peripheral arteriolar tone in man. Lancet 2,997-1000[Medline]
  21. Angus, J. A., Dyke, A. C., Jennings, G. L., Korner, P. I., Sudhir, K., Ward, J. E., Wright, C. E. (1992) Release of endothelium-derived relaxing factor from resistance arteries in hypertension. Kidney Int. 37,S73-S78
  22. Ribeiro, M. O., Antunes, E., de Nucci, G., Lovisolo, S. M., Zatz, R. (1992) Chronic inhibition of nitric oxide synthesis: a new model of arterial hypertension. Hypertension 20,298-303[Abstract/Free Full Text]
  23. Hu, L., Manning, R. D., Jr., Brands, M. W. (1994) Long term cardiovascular role of nitric oxide in conscious rats. Hypertension 23,185-194[Abstract/Free Full Text]
  24. Malinski, T., Kapturczak, M., Dayharsh, J., Bohr, D. (1993) Nitric oxide synthase activity in genetic hypertension. Biochem. Biophys. Res. Commun. 194,654-658[CrossRef][Medline]
  25. McIntyre, M., Hamilton, C. A., Rees, D. D., Reid, J. L., Dominiczak, A. F. (1997) Sex differences in the abundance of endothelial nitric oxide in a model of genetic hypertension. Hypertension 30,1517-1524[Abstract/Free Full Text]
  26. Treasure, C. B., Manoukian, S. V., Klein, J. L., Vita, J. A., Nabel, E. G., Renwick, G. H., Selwyn, A. P., Alexander, R. W., Ganz, P. (1992) Epicardial coronary artery responses to acetylcholine are impaired in hypertensive patients. Circ. Res. 71,776-781[Abstract/Free Full Text]
  27. Cockroft, J. R., Chowiencyk, P. J., Benjamin, N., Ritter, J. M. (1994) Preserved endothelium-dependent vasodilatation in patients with essential hypertension. N. Engl. J. Med. 330,1036-1040[Abstract/Free Full Text]
  28. Laurent, S., Lacolley, P., Brunel, P., Laloux, B., Pannier, B., Safar, M. (1990) Flow-dependent vasodilatation of brachial artery in essential hypertension. Am. J. Physiol. 258,H1004-H1011
  29. Wei, E. P., Kontos, H. A., Christman, C. W., De Witt, D. S., Povlishock, J. T. (1985) Superoxide generation and reversal of acetylcholine-induced cerebral arteriolar dilation after acute hypertension. Circ. Res. 57,781-787[Abstract/Free Full Text]
  30. Gryglewski, R. J., Palmer, R. M. J., Moncada, S. (1986) Superoxide anion is involved in the breakdown of endothelium derived vascular relaxing factor. Nature (London) 320,454-456[CrossRef][Medline]
  31. Salvemini, D., Wang, Z. Q., Bourdon, D. M., Stern, M. K., Currie, M. G., Manning, P. T. (1996) Evidence of peroxynitrite involvement in the carrageenan-induced rat paw edema. Eur. J. Pharmacol. 303,217-220[CrossRef][Medline]
  32. Salvemini, D., Riley, D. P., Lennon, P. J., Wang, Z. Q., Currie, M. G., Macarthur, H., Misko, T. P. (1999) Protective effects of a superoxide dismutase mimetic and peroxynitrite decomposition catalysts in endotoxin-induced intestinal damage. Br. J. Pharmacol. 127,685-692[CrossRef][Medline]
  33. Salvemini, D., Wang, Z. Q., Stern, M. K., Currie, M. G., Misko, T. P. (1998) Peroxynitrite decomposition catalysts: therapeutics for peroxynitrite-mediated pathology. Proc. Natl. Acad. Sci. USA 95,2659-2663[Abstract/Free Full Text]
  34. Cuzzocrea, S., Riley, D. P., Caputi, A. P., Salvemini, D. (2001) Antioxidant therapy: a new pharmacological approach in shock, inflammation, and ischemia/reperfusion injury. Pharmacol. Rev. 53,135-159[Abstract/Free Full Text]
  35. Carlos, R., Recklehoff, J. F. (1999) Role of angiotensin and oxidative stress in essential hypertension. Hypertension 34,943-949[Abstract/Free Full Text]
  36. Balzy, M., Kaminski, P. M., Mao, K., Tan, J., Wolin, M. S. (1998) S-nitroglutathione, a product of the reaction between peroxynitrite and glutathione that generates nitric oxide. J. Biol. Chem. 273,32009-32015[Abstract/Free Full Text]
  37. Davidson, C. A., Kaminski, P. M., Wolin, M. S. (1997) NO elicits prolonged relaxation of bovine pulmonary arteries via endogenous peroxynitrite generation. Am. J. Physiol. 273,437-444
  38. Villa, L. M., Salas, E., Darley-Usmar, V. M., Radomski, M. W., Moncada, S. (1994) Peroxynitrite induces both vasodilatation and impaired vascular relaxation in the isolated perfused rat heart. Proc. Natl. Acad. Sci. USA 91,12383-12387[Abstract/Free Full Text]
  39. Kooy, N. W., Royall, J. A. (1994) Agonist-induced peroxynitrite production from endothelial cells. Arch. Biochem. Biophys. 310,352-359[CrossRef][Medline]
  40. Grover, A. K., Samson, S. E., Robinson, S., Kwan, C. Y. (2003) Effects of peroxynitrite on sarcoplasmic reticulum Ca2+ pump in pig coronary artery smooth muscle. Am. J. Physiol. 284,C294-C301
  41. Riley, D. P., Henke, S. L., Lennon, P. J., Weiss, R. H., Neumann, W. L., Rivers, W. J., Aston, K. W., Sample, K. R., Ling, C. S., Shieh, J. J., et al (1996) Synthesis, characterization and stability of manganese (II) C-substituted 1,4,7,10,13-pentaazacyclopentadecane complexes exhibiting superoxide dismutase activity. Inorg. Chem. 35,5213-5231[CrossRef]
  42. Riley, D. P., Lennon, P. J., Neumann, W. L., Weiss, R. H. (1997) Toward the rational design of superoxide dismutase mimics: mechanistic studies for the elucidation of substituent effects on the catalysis activity of macrocyclic manganese (II) complexes. J. Am. Chem. Soc. 119,6522-6529[CrossRef]
  43. Salvemini, D., Riley, D. P., Lennon, P. J., Wang, Z. Q., Currie, M. G., Macarthur, H., Misko, T. P. (1999) Protective effects of a superoxide dismutase mimetic and peroxynitrite decomposition catalysts in endotoxin-induced intestinal damage. Br. J. Pharmacol. 127,685-692
  44. Salvemini, D., Mazzon, E., Dugo, L., Riley, D. P., Serraino, I., Caputi, A.P., Cuzzocrea, S. (2001) Pharmacological manipulation of the inflammatory cascade by a selective superoxide dismutase mimetic, M40403. Br. J. Pharmacol. 132,815-827[CrossRef][Medline]
  45. Salvemini, D., Wang, Z. Q., Zweier, J. L., Samouilov, A., Macarthur, H., Misko, T. P., Currie, M. G., Cuzzocrea, S., Riley, D. (1999) Synzymes: potent non-peptidic agents against superoxide-driven tissue injury. Science 286,304-306[Abstract/Free Full Text]
  46. Salvemini, D., Mazzon, E., Dugo, L., Serraino, I., De Sarro, A., Caputi, A. P., Cuzzocrea, S. (2001) M40403, a superoxide dismutase mimetic, ameliorates joint disease in a rat model of collagen-induced arthritis. Arthritis Rheum. 44,2909-2922[CrossRef][Medline]
  47. Cuzzocrea, S., Mazzon, E., Dugo, L., Caputi, A. P., Aston, K., Riley, D. P., Salvemini, D. (2001) Protective effects of a new stable, highly active SOD mimetic, M40401 in splanchnic artery occlusion and reperfusion. Br. J. Pharmacol. 132,19-29[CrossRef][Medline]
  48. Cuzzocrea, S., Zingarelli, B., Costantino, G., Szabo, A., Salzman, A. L., Caputi, A. P., Szabo, C. (1997) Beneficial effects of 3-aminobenzamide, an inhibitor of poly (ADP-ribose) synthetase in a rat model of splanchnic artery occlusion and reperfusion. Br. J. Pharmacol. 121,1065-1074[CrossRef][Medline]
  49. Laursen, J. B., Rajagoplan, S., Galis, Z., Tarpey, M., Freeman, B. A., Harrison, D. G. (1997) Role of superoxide in angiotensin II-induced but not catecholamine-induced hypertension. Circulation 95,588-593[Abstract/Free Full Text]
  50. McIntyre, M., Bohr, D. F., Dominiczak, A. F. (1999) Endothelial function in hypertension. The role of superoxide anion. Hypertension 34,539-545[Abstract/Free Full Text]
  51. Schnackenberg, C. G., Welch, W. J., Wilcox, C. S. (1998) Normalization of blood pressure and renal vascular resistance in SHR with a membrane-permeable superoxide dismutase mimetic: role of nitric oxide. Hypertension 32,59-64
  52. Miyamoto, Y., Akaikwe, T., Yoshida, M., Goto, S., Horie, H., Maeda, H. (1996) Potentiation of nitric oxide-mediated vasorelaxation by xanthine-oxidase inhibitors. Proc. Soc. Exp. Biol. Med. 211,366-373[Abstract]
  53. Baylis, C., Mitruka, B., Deng, A. (1992) Chronic blockade of nitric oxide synthesis in the rat produces systemic hypertension and glomerular damage. J. Clin. Invest. 90,278-281
  54. Granger, J. P., Alberola, A. M., Salazar, F. J., Nakamura, T. (1992) Control of renal hemodynamics during intrarenal and systemic blockade of nitric oxide synthesis in conscious dogs. J. Cardiovasc. Pharmacol. 20,S160-S162
  55. Haynes, W. G., Noon, J. P., Walker, B. R., Webb, D. J. (1993) Inhibition of nitric oxide synthesis increases blood pressure in healthy humans. J. Hypertens. 11,1375-1380[Medline]
  56. Rubanyi, G. M., Vanhoutte, P. M. (1986) Superoxide anions and hyperoxia inactivate endothelium-derived relaxing factor. Am. J. Physiol. 250,H822-H827
  57. Szabó, C., Zingarelli, B., Salzman, A. L. (1996) Role of poly-ADP ribosyltransferase activation in the nitric oxide- and peroxynitrite-induced vascular failure. Circ. Res. 78,1051-1063[Abstract/Free Full Text]
  58. Szabó, C., Cuzzocrea, S., Zingarelli, B., O’Connor, M., Salzman, A. L. (1997) Endothelial dysfunction in endotoxic shock: importance of the activation of poly (ADP ribose synthetase (PARS) by peroxynitrite. J. Clin. Invest. 100,723-735[Medline]
  59. Beckman, J. S. (1996) Oxidative damage and tyrosine nitration from peroxynitrite. Chem. Res. Toxicol. 9,836-844[CrossRef][Medline]
  60. Eiserich, J. P., Hristova, M., Cross, C. E., Jones, A. D., Freeman, B. A., Halliwell, B., Van Der Vliet, A. (1998) Formation of nitric oxide-derived inflammatory oxidants by myeloperoxidase in neutrophils. Nature (London) 391,393-397[CrossRef][Medline]
  61. Samuni, A., Winkelsberg, D., Pinson, A., Hahn, S. M., Mitchell, J. B., Russo, A. (1991) Nitroxide stable radicals protect beating cardiomyocytes against oxidative damage. Clin. Invest. 87,1526-1530
  62. Landino, L. M., Crews, B. C., Timmons, M. D., Morrow, J. D., Marnett, L. J. (1996) Peroxynitrite, the coupling product of nitric oxide and superoxide, activates prostaglandin biosynthesis. Proc. Natl. Acad. Sci. USA 93,15069-15074[Abstract/Free Full Text]



This article has been cited by other articles:


Home page
 Physiol. Rev.Home page
P. Pacher, J. S. Beckman, and L. Liaudet
Nitric Oxide and Peroxynitrite in Health and Disease
Physiol Rev, January 1, 2007; 87(1): 315 - 424.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
B. Rodriguez-Iturbe, L. Sepassi, Y. Quiroz, Z. Ni, and N. D. Vaziri
Association of mitochondrial SOD deficiency with salt-sensitive hypertension and accelerated renal senescence
J Appl Physiol, January 1, 2007; 102(1): 255 - 260.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Heart Circ. Physiol.Home page
M. Feletou and P. M. Vanhoutte
Endothelial dysfunction: a multifaceted disorder (The Wiggers Award Lecture)
Am J Physiol Heart Circ Physiol, September 1, 2006; 291(3): H985 - H1002.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
L. Yanes, D. Romero, R. Iliescu, V. E. Cucchiarelli, L. A. Fortepiani, F. Santacruz, W. Bell, H. Zhang, and J. F. Reckelhoff
Systemic arterial pressure response to two weeks of Tempol therapy in SHR: involvement of NO, the RAS, and oxidative stress
Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2005; 288(4): R903 - R908.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Heart Circ. Physiol.Home page
M. Benderdour, G. Charron, B. Comte, R. Ayoub, D. Beaudry, S. Foisy, D. deBlois, and C. Des Rosiers
Decreased cardiac mitochondrial NADP+-isocitrate dehydrogenase activity and expression: a marker of oxidative stress in hypertrophy development
Am J Physiol Heart Circ Physiol, November 1, 2004; 287(5): H2122 - H2131.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
A. Svatikova, R. Wolk, H. H. Wang, M. E. Otto, K. A. Bybee, R. J. Singh, and V. K. Somers
Circulating free nitrotyrosine in obstructive sleep apnea
Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2004; 287(2): R284 - R287.
[Abstract] [Full Text] [PDF]

Home page
 J. Lipid Res.Home page
V. Saraswathi, G. Wu, M. Toborek, and B. Hennig
Linoleic acid-induced endothelial activation: role of calcium and peroxynitrite signaling
J. Lipid Res., May 1, 2004; 45(5): 794 - 804.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by CUZZOCREA, S.
Right arrow Articles by SALVEMINI, D.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by CUZZOCREA, S.
Right arrow Articles by SALVEMINI, D.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS