scholarly journals The effect of continuous light exposure of rats on cardiac response to ischemia-reperfusion and NO-synthase activity.

2007 ◽  
pp. S63-S69
Author(s):  
R Važan ◽  
P Janega ◽  
S Hojná ◽  
J Zicha ◽  
F Šimko ◽  
...  
Keyword(s):  
Light Exposure ◽  
Ischemia Reperfusion ◽  
Continuous Light ◽  
Left Ventricular ◽  
No Synthase ◽  
Cardiac Response ◽  
No Production ◽  
Male Adult ◽  
Functional Parameters ◽  
Isolated Hearts

Factors modulating cardiac susceptibility to ischemia-reperfusion (I/R) are permanently attracting the attention of experimental cardiology research. We investigated, whether continuous 24 h/day light exposure of rats can modify cardiac response to I/R, NO-synthase (NOS) activity and the level of oxidative load represented by conjugated dienes (CD) concentration. Two groups of male adult Wistar rats were studied: controls exposed to normal light/dark cycle (12 h/day light, 12 h/day dark) and rats exposed to continuous light for 4 weeks. Perfused isolated hearts (Langendorff technique) were exposed to 25 min global ischemia and subsequent 30 min reperfusion. The recovery of functional parameters (coronary flow, left ventricular developed pressure, contractility and relaxation index) during reperfusion as well as the incidence, severity and duration of arrhythmias during first 10 min of reperfusion were determined. The hearts from rats exposed to continuous light showed more rapid recovery of functional parameters but higher incidence, duration and severity of reperfusion arrhythmias compared to controls. In the left ventricle, the NOS activity was attenuated, but the CD concentration was not significantly changed. We conclude that the exposure of rats to continuous light modified cardiac response to I/R. This effect could be at least partially mediated by attenuated NO production.

Acute treatment with polyphenol quercetin improves postischemic recovery of isolated perfused rat hearts after global ischemia

2010 ◽  
Vol 88 (4) ◽  
pp. 465-471 ◽  
Author(s):  
Monika Barteková ◽  
Slávka Čarnická ◽  
Dezider Pancza ◽  
Mária Ondrejčáková ◽  
Albert Breier ◽  
...  
Keyword(s):  
Cardiovascular System ◽  
Ischemia Reperfusion ◽  
Left Ventricular ◽  
Global Ischemia ◽  
Functional Parameters ◽  
Beneficial Effects ◽  
Isolated Hearts ◽  
Positive Effects ◽  
Rat Hearts ◽  
Postischemic Recovery

Quercetin is a plant-derived bioflavonoid with potentially beneficial effects on the cardiovascular system. Studies focused on the efficiency of flavonoids against ischemia–reperfusion (I/R) injury have demonstrated that quercetin exerts robust protective effects in renal, cerebral, and hepatic I/R models. However, there is only limited evidence about the effect of quercetin on myocardial I/R injury. Therefore, the aim of the current study was to examine the effect of quercetin on isolated rat heart during ischemia and reperfusion. Rat hearts perfused according to Langendorff at 37 °C were examined during 25 min global ischemia followed by 120 min reperfusion. Quercetin (15 µmol/L) was administered either 15 min before ischemia (group Q1), or during the entire reperfusion period (group Q2). Changes in functional parameters of the hearts were measured during the initial 40 min of reperfusion. At the end of the experiment, the hearts were stained with tetrazolium to estimate the size of infarction (IS). Our study showed that quercetin improved postischemic recovery of functional parameters of isolated hearts in both treated groups. This improvement was manifested by significantly higher values of left ventricular developed pressure (LVDP) and the maximal rates of pressure development and fall (+(dP/dt)max and –(dP/dt)max) and by significantly lower increase of end-diastolic pressure. Coronary flow was not significantly changed during reperfusion in the group treated before ischemia, but was significantly increased in the group treated during reperfusion. Quercetin also significantly reduced IS in both groups, more markedly in postischemically treated group. We conclude that acute quercetin treatment exerts significant positive effects on isolated hearts during I/R injury. These results are consistent with the beneficial effects of quercetin and other flavonoids on the cardiovascular system.

Blocking Na+/H+ exchange reduces [Na+]i and [Ca2+]i load after ischemia and improves function in intact hearts

2001 ◽  
Vol 281 (6) ◽  
pp. H2398-H2409 ◽  
Author(s):  
Jianzhong An ◽  
Srinivasan G. Varadarajan ◽  
Amadou Camara ◽  
Qun Chen ◽  
Enis Novalija ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Infarct Size ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Ringer Solution ◽  
Left Ventricular ◽  
Isolated Hearts ◽  
Intracellular Ca ◽  
Ionic Basis

We determined in intact hearts whether inhibition of Na+/H+ exchange (NHE) decreases intracellular Na+ and Ca2+ during ischemia and reperfusion, improves function during reperfusion, and reduces infarct size. Guinea pig isolated hearts were perfused with Krebs-Ringer solution at 37°C. Left ventricular (LV) free wall intracellular Na+ concentration ([Na+]i) and intracellular Ca2+ concentration ([Ca2+]i) were measured using fluorescence dyes. Hearts were exposed to 30 min of ischemia with or without 10 μM of benzamide (BIIB-513), a selective NHE-1 inhibitor, infused for 10 min just before ischemia or for 10 min immediately on reperfusion. At 2 min of reperfusion, BIIB-513 given before ischemia decreased peak increases in [Na+]i and [Ca2+]i, respectively, from 2.5 and 2.3 times (controls) to 1.6 and 1.3 times preischemia values. At 30 min of reperfusion, BIIB-513 increased systolic-diastolic LV pressure (LVP) from 49 ± 2% (controls) to 80 ± 2% of preischemia values. BIIB-513 reduced ventricular fibrillation by 54% and reduced infarct size from 64 ± 1% to 20 ± 3%. First derivative of the LVP, O2 consumption, and cardiac efficiency were also improved by BIIB-513. Similar results were obtained with BIIB-513 given on reperfusion. These data show that Na+ loading is a marker of reperfusion injury in intact hearts in that inhibiting NHE reduces Na+ and Ca2+ loading during reperfusion while improving function. These results clearly implicate the ionic basis by which inhibiting NHE protects the guinea pig intact heart from ischemia-reperfusion injury.

scholarly journals Resveratrol improves left ventricular diastolic relaxation in type 2 diabetes by inhibiting oxidative/nitrative stress: in vivo demonstration with magnetic resonance imaging

2010 ◽  
Vol 299 (4) ◽  
pp. H985-H994 ◽  
Author(s):  
Hanrui Zhang ◽  
Brandon Morgan ◽  
Barry J. Potter ◽  
Lixin Ma ◽  
Kevin C. Dellsperger ◽  
...  
Keyword(s):  
Protein Expression ◽  
Left Ventricular ◽  
No Synthase ◽  
No Production ◽  
Enos Expression ◽  
Nitrative Stress ◽  
Tnf Α ◽  
Mrna And Protein Expression

Resveratrol is a natural phytophenol that exhibits cardioprotective effects. This study was designed to elucidate the mechanisms by which resveratrol protects against diabetes-induced cardiac dysfunction. Normal control ( m-Lepr db) mice and type 2 diabetic ( Lepr db) mice were treated with resveratrol orally for 4 wk. In vivo MRI showed that resveratrol improved cardiac function by increasing the left ventricular diastolic peak filling rate in Lepr db mice. This protective role is partially explained by resveratrol's effects in improving nitric oxide (NO) production and inhibiting oxidative/nitrative stress in cardiac tissue. Resveratrol increased NO production by enhancing endothelial NO synthase (eNOS) expression and reduced O2·− production by inhibiting NAD(P)H oxidase activity and gp91phox mRNA and protein expression. The increased nitrotyrosine (N-Tyr) protein expression in Lepr db mice was prevented by the inducible NO synthase (iNOS) inhibitor 1400W. Resveratrol reduced both N-Tyr and iNOS expression in Lepr db mice. Furthermore, TNF-α mRNA and protein expression, as well as NF-κB activation, were reduced in resveratrol-treated Lepr db mice. Both Lepr db mice null for TNF-α ( dbTNF−/ dbTNF− mice) and Lepr db mice treated with the NF-κB inhibitor MG-132 showed decreased NAD(P)H oxidase activity and iNOS expression as well as elevated eNOS expression, whereas m-Lepr db mice treated with TNF-α showed the opposite effects. Thus, resveratrol protects against cardiac dysfunction by inhibiting oxidative/nitrative stress and improving NO availability. This improvement is due to the role of resveratrol in inhibiting TNF-α-induced NF-κB activation, therefore subsequently inhibiting the expression and activation of NAD(P)H oxidase and iNOS as well as increasing eNOS expression in type 2 diabetes.

The nitric oxide donor molsidomine rescues cardiac function in rats with chronic kidney disease and cardiac dysfunction

2010 ◽  
Vol 299 (6) ◽  
pp. H2037-H2045 ◽  
Author(s):  
Lennart G. Bongartz ◽  
Branko Braam ◽  
Marianne C. Verhaar ◽  
Maarten Jan M. Cramer ◽  
Roel Goldschmeding ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Low Dose ◽  
Left Ventricular Systolic Dysfunction ◽  
Systolic Dysfunction ◽  
Systolic Pressure ◽  
Left Ventricular ◽  
No Synthase ◽  
Nitric Oxide Donor ◽  
No Production ◽  
No Donor

We recently developed a rat model of cardiorenal failure that is characterized by severe left ventricular systolic dysfunction (LVSD) and low nitric oxide (NO) production that persisted after temporary low-dose NO synthase inhibition. We hypothesized that LVSD was due to continued low NO availability and might be reversed by supplementing NO. Rats underwent a subtotal nephrectomy and were treated with low-dose NO synthase inhibition with Nω-nitro-l-arginine up to week 8. After 3 wk of washout, rats were treated orally with either the long-acting, tolerance-free NO donor molsidomine (Mols) or vehicle (Veh). Cardiac and renal function were measured on weeks 11, 13, and 15. On week 16, LV hemodynamics and pressure-volume relationships were measured invasively, and rats were killed to quantify histological damage. On week 15, blood pressure was mildly reduced and creatinine clearance was increased by Mols (both P < 0.05). Mols treatment improved ejection fraction (53 ± 3% vs. 37 ± 2% in Veh-treated rats, P < 0.001) and stroke volume (324 ± 33 vs. 255 ± 15 μl in Veh-treated rats, P < 0.05). Rats with Mols treatment had lower end-diastolic pressures (8.5 ± 1.1 mmHg) than Veh-treated rats (16.3 ± 3.5 mmHg, P < 0.05) and reduced time constants of relaxation (21.9 ± 1.8 vs. 30.9 ± 3.3 ms, respectively, P < 0.05). The LV end-systolic pressure-volume relationship was shifted to the left in Mols compared with Veh treatment. In summary, in a model of cardiorenal failure with low NO availability, supplementing NO significantly improves cardiac systolic and diastolic function without a major effect on afterload.

scholarly journals Hypertension and Cardiovascular Remodelling in Rats Exposed to Continuous Light: Protection by ACE-Inhibition and Melatonin

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Fedor Simko ◽  
Olga Pechanova ◽  
Kristina Repova Bednarova ◽  
Kristina Krajcirovicova ◽  
Peter Celec ◽  
...  
Keyword(s):  
Enzyme Inhibitor ◽  
Light Exposure ◽  
Hypertensive Heart Disease ◽  
Continuous Light ◽  
Ace Inhibition ◽  
Left Ventricular ◽  
Cross Sectional ◽  
Light Protection ◽  
Male Wistar Rats ◽  
Hypertension Development

Exposure of rats to continuous light attenuates melatonin production and results in hypertension development. This study investigated whether hypertension induced by continuous light (24 hours/day) exposure induces heart and aorta remodelling and if these alterations are prevented by melatonin or angiotensin converting enzyme inhibitor captopril. Four groups of 3-month-old male Wistar rats (10 per group) were treated as follows for six weeks: untreated controls, exposed to continuous light, light-exposed, and treated with either captopril (100 mg/kg/day) or melatonin (10 mg/kg/day). Exposure to continuous light led to hypertension, left ventricular (LV) hypertrophy and fibrosis, and enhancement of the oxidative load in the LV and aorta. Increase in systolic blood pressure by continuous light exposure was prevented completely by captopril and partially by melatonin. Both captopril and melatonin reduced the wall thickness and cross-sectional area of the aorta and reduced the level of oxidative stress. However, only captopril reduced LV hypertrophy development and only melatonin reduced LV hydroxyproline concentration in insoluble and total collagen in rats exposed to continuous light. In conclusion, captopril prevented LV hypertrophy development in the continuous light-induced hypertension model, while only melatonin significantly reduced fibrosis. This antifibrotic action of melatonin may be protective in hypertensive heart disease.

scholarly journals Differences in ischemia-reperfusion-induced endothelial changes in hearts perfused at constant flow and constant pressure

2008 ◽  
Vol 105 (6) ◽  
pp. 1779-1787 ◽  
Author(s):  
Raja B. Singh ◽  
Vijayan Elimban ◽  
Naranjan S. Dhalla
Keyword(s):  
Cardiac Function ◽  
Constant Pressure ◽  
Contractile Activity ◽  
Ischemia Reperfusion ◽  
No Synthase ◽  
Constant Flow ◽  
Calpain Activity ◽  
Isolated Hearts ◽  
Rat Hearts ◽  
Perfused Hearts

Isolated hearts subjected to ischemia-reperfusion (I/R) exhibit depressed cardiac performance and alterations in subcellular function. Since hearts perfused at constant flow (CF) and constant pressure (CP) show differences in their contractile response to I/R, this study was undertaken to examine mechanisms responsible for these I/R-induced alterations in CF-perfused and CP-perfused hearts. Rat hearts, perfused at CF (10 ml/min) or CP (80 mmHg), were subjected to I/R (30 min global ischemia followed by 60 min reperfusion), and changes in cardiac function as well as sarcolemmal (SL) Na+-K+-ATPase activity, sarcoplasmic reticulum (SR) Ca2+ uptake, and endothelial function were monitored. The I/R-induced depressions in cardiac function, SL Na+-K+-ATPase, and SR Ca2+-uptake activities were greater in hearts perfused at CF than in hearts perfused at CP. In hearts perfused at CF, I/R-induced increase in calpain activity and decrease in nitric oxide (NO) synthase (endothelial NO synthase) protein content in the heart as well as decrease in NO concentration of the perfusate were greater than in hearts perfused at CP. These changes in contractile activity and biochemical parameters due to I/R in hearts perfused at CF were attenuated by treatment with l-arginine, a substrate for NO synthase, while those in hearts perfused at CP were augmented by treatment with NG-nitro-l-arginine methyl ester, an inhibitor of NO synthase. The results indicate that the I/R-induced differences in contractile responses and alterations in subcellular organelles between hearts perfused at CF and CP may partly be attributed to greater endothelial dysfunction in CF-perfused hearts than that in CP-perfused hearts.

Bax ablation protects against myocardial ischemia-reperfusion injury in transgenic mice

2003 ◽  
Vol 284 (6) ◽  
pp. H2351-H2359 ◽  
Author(s):  
Edith Hochhauser ◽  
Shaye Kivity ◽  
Daniel Offen ◽  
Nilanjana Maulik ◽  
Hajime Otani ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Left Ventricular ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Electron Microscopic ◽  
Isolated Hearts ◽  
Microscopic Evaluation ◽  
Myocardial Ischemia Reperfusion ◽  
Bax Gene

The role of the proapototic Bax gene in ischemia-reperfusion (I/R) injury was studied in three groups of mice: homozygotic knockout mice lacking the Bax gene (Bax−/−), heterozygotic mice (Bax+/−), and wild-type mice (Bax+/+). Isolated hearts were subjected to ischemia (30 min, 37°C) and then to 120 min of reperfusion. The left ventricular developed force of Bax-deficient vs. Bax+/+ hearts at stabilization and at 120 min of reperfusion was 1,411 ± 177 vs. 1,161 ± 137 mg and 485 ± 69 vs. 306 ± 68 mg, respectively. Superior cardiac function of Bax−/− hearts after I/R was accompanied by a decrease in creatine kinase release, caspase 3 activity, irreversible ischemic injury, and the number of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive cardiomyocytes. Electron microscopic evaluation revealed reduced damage to mitochondria and the nuclear chromatin structure in Bax-deficient mice. In the Bax+/− hearts, the damage markers were moderate. The superior tolerance of Bax knockout hearts to I/R injury recommends this gene as a potential target for therapeutic intervention in patients with severe and intractable myocardial ischemia.

Intracoronary intermedin 1–47 augments cardiac perfusion and function in anesthetized pigs: role of calcitonin receptors and β-adrenoreceptor-mediated nitric oxide release

2009 ◽  
Vol 107 (4) ◽  
pp. 1037-1050 ◽  
Author(s):  
Elena Grossini ◽  
Claudio Molinari ◽  
David A. S. G. Mary ◽  
Francesca Uberti ◽  
Philippe Primo Caimmi ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Cardiac Function ◽  
Coronary Blood Flow ◽  
No Synthase ◽  
Cardiac Response ◽  
No Production ◽  
Receptor Complexes ◽  
Arterial Blood

Systemic intermedin (IMD)1–47 administration has been reported to result in vasodilation and marked hypotension through calcitonin-related receptor complexes. However, its effects on the coronary circulation and the heart have not been examined in vivo. The present study was therefore planned to determine the primary in vivo effect of IMD1–47 on coronary blood flow and cardiac function and the involvement of the autonomic nervous system and nitric oxide (NO). In 35 anesthetized pigs, IMD1–47, infused into the left anterior descending coronary artery at doses of 87.2 pmol/min, at constant heart rate and arterial blood pressure, augmented coronary blood flow and cardiac function. These responses were graded in a further five pigs by increasing the infused dose of IMD1–47 between 0.81 and 204.1 pmol/min. In the 35 pigs, the blockade of cholinergic receptors (intravenous atropine, 5 pigs), α-adrenoceptors (intravenous phentolamine, 5 pigs), and β1-adrenoceptors (intravenous atenolol, 5 pigs) did not abolish the cardiac response to IMD1–47, the effects of which were prevented by blockade of β2-adrenoceptors (intravenous butoxamine, 5 pigs), NO synthase (intracoronary Nω-nitro-l-arginine methyl ester, 5 pigs), and calcitonin-related receptors (intracoronary CGRP8–37/AM22–52, 10 pigs). In porcine coronary endothelial cells, IMD1–47 induced the phosphorylation of endothelial NO synthase and NO production through cAMP signaling leading to ERK, Akt, and p38 activation, which was prevented by the inhibition of β2-adrenoceptors, calcitonin-related receptor complexes, and K+ channels. In conclusion, IMD1–47 primarily augmented coronary blood flow and cardiac function through the involvement of calcitonin-related receptor complexes and β2-adrenoreceptor-mediated NO release. The intracellular signaling involved cAMP-dependent activation of kinases and the opening of K+ channels.

Anesthetic Preconditioning Enhances Ca2+Handling and Mechanical and Metabolic Function Elicited by Na+–Ca2+Exchange Inhibition in Isolated Hearts

2006 ◽  
Vol 105 (3) ◽  
pp. 541-549 ◽  
Author(s):  
Jianzhong An ◽  
Samhita S. Rhodes ◽  
Ming Tao Jiang ◽  
Zeljko J. Bosnjak ◽  
Ming Tian ◽  
...  
Keyword(s):  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Left Ventricular ◽  
Release Channel ◽  
Western Blots ◽  
Isolated Hearts ◽  
Time Control ◽  
Anesthetic Preconditioning ◽  
Myocardial Ischemia Reperfusion

Background Anesthetic preconditioning (APC) is well known to protect against myocardial ischemia-reperfusion injury. Studies also show the benefit of Na+-Ca2+ exchange inhibition on ischemia-reperfusion injury. The authors tested whether APC plus Na+-Ca2+ exchange inhibitors given just on reperfusion affords additive protection in intact hearts. Methods Cytosolic [Ca2+] was measured by fluorescence at the left ventricular wall of guinea pig isolated hearts using indo-1 dye. Sarcoplasmic reticular Ca2+-cycling proteins, i.e., Ca2+ release channel (ryanodine receptor [RyR2]), sarcoplasmic reticular Ca2+-pump adenosine triphosphatase (SERCA2a), and phospholamban were measured by Western blots. Hearts were assigned to seven groups (n = 8 each): (1) time control; (2) ischemia; (3, 4) 10 microM Na+-Ca2+ exchange inhibitor KB-R7943 (KBR) or 1 microM SEA0400 (SEA), given during the first 10 min of reperfusion; (5) APC initiated by sevoflurane (2.2%, 0.41 +/- 0.03 mm) given for 15 min and washed out for 15 min before ischemia-reperfusion; (6, 7) APC plus KBR or SEA. Results The authors found that APC reduced the increase in systolic [Ca2+], whereas KBR and SEA both reduced the increase in diastolic [Ca2+] on reperfusion. Each intervention improved recovery of left ventricular function. Moreover, APC plus KBR or SEA afforded better functional recovery than APC, KBR, or SEA alone (P &lt; 0.05). Ischemia-reperfusion-induced degradation of major sarcoplasmic reticular Ca2+-cycling proteins was attenuated by APC, but not by KBR or SEA. Conclusions APC plus Na+-Ca2+ exchange inhibition exerts additive protection in part by reducing systolic and diastolic Ca2+ overload, respectively, during ischemia-reperfusion. Less degradation of sarcoplasmic reticular Ca2+-cycling proteins may also contribute to cardiac protection.

Sign in / Sign up

Export Citation Format

Share Document