Nitric oxide synthase inhibition in rats: Melatonin reduces blood pressure and ischemia/reperfusion-induced infarct size

2006 ◽  
Vol 40 (4) ◽  
pp. 248-252 ◽  
Author(s):  
Esra Deniz ◽  
Engin Sahna ◽  
Hakki Engin Aksulu
Keyword(s):  
Nitric Oxide ◽  
Blood Pressure ◽  
Nitric Oxide Synthase ◽  
Infarct Size ◽  
Ischemia Reperfusion ◽  
Oxide Synthase

Angiotensin II type 1 receptor blocker preserves tolerance to ischemia-reperfusion injury in Dahl salt-sensitive rat heart

2008 ◽  
Vol 294 (6) ◽  
pp. H2473-H2479 ◽  
Author(s):  
Seiji Matsuhisa ◽  
Hajime Otani ◽  
Toru Okazaki ◽  
Koji Yamashita ◽  
Yuzo Akita ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Nitric Oxide ◽  
Angiotensin Ii ◽  
Nitric Oxide Synthase ◽  
Infarct Size ◽  
Rat Heart ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Oxide Synthase

Oxidative stress is involved in the tolerance to ischemia-reperfusion (I/R) injury. Because angiotensin II type 1 receptor blockers (ARBs) inhibit oxidative stress, there is concern that ARBs abolish the tolerance to I/R injury. Dahl salt-sensitive (DS) hypertensive and salt-resistant (DR) normotensive rats received an antioxidant, 2-mercaptopropionylglycine (MPG), or an ARB, losartan, for 7 days. Losartan and MPG significantly inhibited oxidative stress as determined by tissue malondialdehyde + 4-hydroxynoneal and increased expression of inducible nitric oxide synthase (iNOS) in the DS rat heart. However, losartan but not MPG activated endothelial nitric oxide synthase (eNOS) as assessed by phosphorylation of eNOS on Ser1177. Infarct size after 30-min left coronary artery occlusion followed by 2-h reperfusion was comparable between DS and DR rat hearts. Although MPG and losartan had no effect on infarct size in the DR rat heart, MPG but not losartan significantly increased infarct size in the DS rat heart. A selective iNOS inhibitor, 1400W, increased infarct size in the DS rat heart, but it had no effect on infarct size in the losartan-treated DS rat heart. However, a nonselective NOS inhibitor, Nω-nitro-l-arginine methyl ester, increased infarct size in the losartan-treated DS rat heart. These results suggest that losartan preserves the tolerance to I/R injury by activating eNOS despite elimination of redox-sensitive upregulation of iNOS and iNOS-dependent cardioprotection in the DS rat heart.

scholarly journals ERK phosphorylation mediates sildenafil-induced myocardial protection against ischemia-reperfusion injury in mice

2009 ◽  
Vol 296 (5) ◽  
pp. H1236-H1243 ◽  
Author(s):  
Anindita Das ◽  
Fadi N. Salloum ◽  
Lei Xi ◽  
Yuan J. Rao ◽  
Rakesh C. Kukreja
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Infarct Size ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Global Ischemia ◽  
Erk Phosphorylation ◽  
Gsk 3Β ◽  
Oxide Synthase

Sildenafil, a selective inhibitor of phosphodiesterase type 5, induces powerful protection against myocardial ischemia-reperfusion injury through activation of cGMP-dependent protein kinase (PKG). We further hypothesized that PKG-dependent activation of survival kinase ERK may play a causative role in sildenafil-induced cardioprotection via induction of endothelial nitric oxide synthase (eNOS)/inducible nitric oxide synthase (iNOS) and Bcl-2. Our results show that acute intracoronary infusion of sildenafil in Langendorff isolated mouse hearts before global ischemia-reperfusion significantly reduced myocardial infarct size (from 29.4 ± 2.4% to 15.9 ± 3.0%; P < 0.05). Cotreatment with ERK inhibitor PD98059 abrogated sildenafil-induced protection (31.8 ± 4.4%). To further evaluate the role of ERK in delayed cardioprotection, mice were treated with sildenafil (ip) 24 h before global ischemia-reperfusion. PD98059 was administered (ip) 30 min before sildenafil treatment. Infarct size was reduced from 27.6 ± 3.3% in controls to 7.1 ± 1.5% in sildenafil-treated mice ( P < 0.05). The delayed protective effect of sildenafil was also abolished by PD98059 (22.5 ± 2.3%). Western blots revealed that sildenafil significantly increased phosphorylation of ERK1/2 and GSK-3β and induced iNOS, eNOS, Bcl-2, and PKG activity in the heart 24 h after treatment. PD98059 inhibited the enhanced expression of iNOS, eNOS, and Bcl-2 and the phosphorylation of GSK-3β. PD98059 had no effect on the sildenafil-induced activation of PKG. We conclude that these studies provide first direct evidence that PKG-dependent ERK phosphorylation is indispensable for the induction of eNOS/iNOS and Bcl-2 and the resulting cardioprotection by sildenafil.

Abstract 1396: Mitigation Of Cardiac Injury By Sulfaphenazole, A CYP2C9 Inhibitor Through Involvement Of Inducible Nitric Oxide Synthase (iNOS) in Post-ischemic Heart

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Mahmood Khan ◽  
Iyyapu K Mohan ◽  
Damodhar Kumbala ◽  
Vijay K Kutala ◽  
Periannan Kuppusamy
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Infarct Size ◽  
Ischemia Reperfusion ◽  
Left Ventricular ◽  
Control Group ◽  
Myocardial Tissue ◽  
Cytochrome P450 Enzymes ◽  
Superoxide Generation ◽  
Oxide Synthase

Cytochrome P450 enzymes play a significant role in ischemia-reperfusion (I/R) injury. Sulfaphenazole (SFZ), a potent CYP2C9 inhibitor, is known to reduce I/R injury. However, the mechanism of its cardioprotective effects and the role of nitric oxide (NO) is not clear. Objective : Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are important mediators of I/R injury. The objective of this study was to determine how SFZ treatment modulates myocardial tissue oxygenation (pO 2 ) and RNS generation in vivo . Methods: Myocardial infarction was induced in rats by ligating the left anterior descending coronary artery (LAD) for 30 min, followed by 24 h of reperfusion. The study was divided into 4 groups: Untreated I/R control, SFZ, L-NAME, and SFZ+L-NAME. L-NAME (100 mg/kg/day), a nitric oxide synthase inhibitor, was given orally for 3 days prior to LAD ligation. SFZ (1.5 mg/kg, ip) was injected 30 min prior to LAD ligation. Oxygen-sensing crystals were implanted into the LV wall and the rat was placed in an L-band (1.2 GHz) electron paramagnetic resonance (EPR) spectrometer for measurement of myocardial tissue pO 2 during I/R injury. Hemodynamic data was collected with a microtip catheter. Infarct size was measured after 24 h of reperfusion. Superoxide generation was determined by dihydroethidium fluorescence imaging. Immunohistological staining was performed for nitrotyrosine and iNOS. Results: After LAD ligation, pO 2 decreased from 18 mmHg baseline to <2 mmHg. At reperfusion, there was a significant myocardial hyperoxygenation in SFZ-treated rats compared to control group (45.0±1.3 vs. 34.0±2.0 mmHg, P<0.05). In L-NAME and L-NAME+SFZ-treated rats, there was a significant reduction in pO 2 (24.0±1.6 and 26.0±2.3 mmHg, respectively). Compared to control, SFZ treatment significantly improved the left ventricular developed pressure (94.0±4.7 vs. 69.0±6.5 mmHg, P<0.05), decreased infarct size % (35.0±4.2 vs. 16.0±2.5, P<0.05), decreased superoxide generation and nitrotyrosine production. Conclusions: These findings demonstrate that SFZ may provide potent cardioprotection by attenuating post-ischemic ROS and RNS generation, and could serve as an attractive adjuvant therapy in the clinical setting of myocardial I/R injury.

Role of TLR-4/IL-6/TNF-α, COX-II and eNOS/iNOS pathways in the impact of carvedilol against hepatic ischemia reperfusion injury

2021 ◽  
pp. 096032712199944
Author(s):  
Mohamed IA Hassan ◽  
Fares EM Ali ◽  
Abdel-Gawad S Shalkami
Keyword(s):  
Oxidative Stress ◽  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Inducible Nitric Oxide Synthase ◽  
Liver Enzymes ◽  
Ischemia Reperfusion ◽  
Hepatic Ischemia ◽  
Hepatic Ischemia Reperfusion ◽  
Oxide Synthase ◽  
Inducible Nitric Oxide

Aim: Hepatic ischemia/reperfusion (I/R) injury is a syndrome involved in allograft dysfunction. This work aimed to elucidate carvedilol (CAR) role in hepatic I/R injury. Methods: Male rats were allocated to Sham group, CAR group, I/R group and CAR plus I/R group. Rats subjected to hepatic ischemia for 30 minutes then reperfused for 60 minutes. Oxidative stress markers, inflammatory cytokines and nitric oxide synthases were measured in hepatic tissues. Results: Hepatocyte injury following I/R was confirmed by a marked increase in liver enzymes. Also, hepatic I/R increased the contents of malondialdehyde however decreased glutathione contents and activities of antioxidant enzymes. Furthermore, hepatic I/R caused elevation of toll-like receptor-4 (TLR-4) expression and inflammatory mediators levels such as tumor necrosis factor-α, interleukin-6 and cyclooxygenase-II. Hepatic I/R caused down-regulation of endothelial nitric oxide synthase and upregulation of inducible nitric oxide synthase expressions. CAR treatment before hepatic I/R resulted in the restoration of liver enzymes. Administration of CAR caused a significant correction of oxidative stress and inflammation markers as well as modulates the expression of endothelial and inducible nitric oxide synthase. Conclusions: CAR protects liver from I/R injury through reduction of the oxidative stress and inflammation, and modulates endothelial and inducible nitric oxide synthase expressions.

Selective neuronal nitric oxide synthase inhibition blocks furosemide-stimulated renin secretion in vivo

1995 ◽  
Vol 269 (1) ◽  
pp. F134-F139 ◽  
Author(s):  
W. H. Beierwaltes
Keyword(s):  
Nitric Oxide ◽  
Blood Pressure ◽  
Nitric Oxide Synthase ◽  
Perfusion Pressure ◽  
Renal Perfusion ◽  
Macula Densa ◽  
Renin Secretion ◽  
Renal Perfusion Pressure ◽  
Neuronal Nos ◽  
Oxide Synthase

The macula densa is a regulatory site for renin. It contains exclusively the neuronal isoform of nitric oxide synthase (NOS), suggesting NO could stimulate renin secretion through the macula densa pathway. To test whether neuronal NOS mediates renin secretion, renin was stimulated by either the renal baroreceptor or the diuretic furosemide (acting through the macula densa pathway). Renin secretion rate (RSR) was measured in 12 Inactin-anesthetized rats at normal (104 +/- 3 mmHg) and reduced renal perfusion pressure (65 +/- 1 mmHg), before and after selective blockade of the neuronal NOS with 7-nitroindazole (7-NI, 50 mg/kg ip). 7-NI had no effect on basal blood pressure (102 +/- 2 mmHg) or renal blood flow (RBF). Decreasing renal perfusion pressure doubled RSR from 11.8 +/- 3.3 to 22.9 +/- 5.7 ng ANG I.h-1.min-1 (P < 0.01) (ANG I is angiotensin I). Similarly, in 7-NI-treated rats, reduced perfusion doubled RSR from 8.5 +/- 1.8 to 20.5 +/- 6.2 ng ANG I.h-1.min-1 (P < 0.01). Renal hemodynamics and RSR were measured in response to 5 mg/kg iv furosemide in 12 control rats and 11 rats treated with 7-NI. Blocking neuronal NOS did not alter blood pressure (102 +/- 2 mmHg), RBF (5.8 +/- 0.4 ml.min-1.g kidney wt-1), or renal vascular resistance (18.7 +/- 1.4 mmHg.ml-1.min.g kidney wt).(ABSTRACT TRUNCATED AT 250 WORDS)

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