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Aghajani M, Aghajani M, Moghaddam EK, Faghihi M, Imani A. Acute sleep deprivation (ASD) and cardioprotection: Impact of ASD on oxytocin-mediated sympathetic nervous activation preceding myocardial infarction. Neuropeptides 2024; 107:102453. [PMID: 38959559 DOI: 10.1016/j.npep.2024.102453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Revised: 05/10/2024] [Accepted: 06/25/2024] [Indexed: 07/05/2024]
Abstract
INTRODUCTION This study explored how acute sleep deprivation (ASD) before myocardial ischemia influences oxytocin release from paraventricular (PVN) neurons and its correlation with sympathetic nervous system (SNS) activity post-acute sleep loss, impacting subsequent left ventricular (LV) remodeling following myocardial infarction (MI). METHODS The study was conducted in two phases: induction of ASD, inducing MI, blood sampling, euthanizing animals and collecting their heart and brain for histological and gene expression evaluations. The animals in first and second phase were euthanized 24 h and 14 days after MI, respectively. RESULTS Pre-MI ASD, accompanied by increased serum epinephrine levels within 24 h of MI, upregulated oxytocin and cFos expression in the PVN. Also, pre-MI ASD resulted in decreased serum PAB levels 14 days post-MI (P < 0.001). While notable echocardiographic changes were seen in MI versus sham groups, ASD demonstrated protective effects. This was evidenced by reduced infarct size, elevated TIMP1, MMP2, and MMP9 in the LV of SD + MI animals versus MI alone (P < 0.05). Additionally, histological analysis showed reduced LV fibrosis in pre-MI ASD subjects (P < 0.05). CONCLUSION Our study supports the notion that activation of oxytocin neurons within the PVN subsequent to ASD interacts with autonomic centers in the central nervous system. This enhanced sympathetic outflow to the heart prior to MI triggers a preconditioning response, thereby mediating cardioprotection through decreased oxidative stress biomarkers and regulated extracellular matrix (ECM) turnover.
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Affiliation(s)
- Marjan Aghajani
- Physiology Department, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mozhgan Aghajani
- Rasoole-Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
| | | | - Mahdieh Faghihi
- Physiology Department, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Alireza Imani
- Physiology Department, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Sleep Breathing Disorders Research Center (SBDRC), Tehran University of Medical Sciences, Tehran, Iran; Occupational Sleep Research Center, Baharloo Hospital, Tehran University of Medical Sciences, Tehran, Iran.
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Shao WJ, Shu TT, Xu S, Liang LC, Grange JML, Zhou YR, Huang H, Cai Y, Zhang Q, Sun P. Left-sided vagus nerve stimulation improves cardiopulmonary resuscitation outcomes in rats as effectively as right-sided vagus nerve stimulation. World J Emerg Med 2021; 12:309-316. [PMID: 34512829 DOI: 10.5847/wjem.j.1920-8642.2021.04.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 06/22/2021] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Our group previously reported that right-sided vagus nerve stimulation (RVNS) significantly improved outcomes after cardiopulmonary resuscitation (CPR) in a rat model of cardiac arrest (CA). However, whether left-sided vagus nerve stimulation (LVNS) could achieve the same effect as RVNS in CPR outcomes remains unknown. METHODS A rat model of CA was established using modified percutaneous epicardial electrical stimulation to induce ventricular fibrillation (VF). Rats were treated with LVNS or RVNS for 30 minutes before the induction of VF. All animals were observed closely within 72 hours after return of spontaneous circulation (ROSC), and their health and behavior were evaluated every 24 hours. RESULTS Compared with those in the RVNS group, the hemodynamic measurements in the LVNS group decreased more notably. Vagus nerve stimulation (VNS) decreased the serum levels of tumor necrosis factor-alpha (TNF-α) and the arrhythmia score, and attenuated inflammatory infiltration in myocardial tissue after ROSC, regardless of the side of stimulation, compared with findings in the CPR group. Both LVNS and RVNS ameliorated myocardial function and increased the expression of α-7 nicotinic acetylcholine receptor in the myocardium after ROSC. Moreover, a clear improvement in 72-hour survival was shown with VNS pre-treatment, with no significant difference in efficacy when comparing the laterality of stimulation. CONCLUSIONS LVNS may have similar effects as RVNS on improving outcomes after CPR.
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Affiliation(s)
- Wei-Jing Shao
- Department of Emergency Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Ting-Ting Shu
- Department of Emergency Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.,Department of Intensive Care Unit, Wuhan Hospital of Traditional Chinese Medicine, Wuhan 430000, China
| | - Shuang Xu
- Department of Emergency Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Li-Cai Liang
- Department of Emergency Medicine, the Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou 310009, China
| | - Jehane Michael Le Grange
- Department of Emergency Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Yu-Ran Zhou
- Department of Emergency Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - He Huang
- Department of Emergency Medicine, Hankou Branch of Central Theater General Hospital, Wuhan 430070, China
| | - Yu Cai
- Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Qing Zhang
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Peng Sun
- Department of Emergency Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
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Edalatyzadeh Z, Aghajani M, Imani A, Faghihi M, Sadeghniiat-Haghighi K, Askari S, Choopani S. Cardioprotective effects of acute sleep deprivation on ischemia/reperfusion injury. Auton Neurosci 2020; 230:102761. [PMID: 33310629 DOI: 10.1016/j.autneu.2020.102761] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 11/08/2020] [Accepted: 12/02/2020] [Indexed: 11/17/2022]
Abstract
OBJECTIVES Modulation of sympathetic activity during acute sleep deprivation can produce various effects on body functions. We studied the effects of acute sleep deprivation before ischemia/reperfusion on myocardial injury in isolated rat hearts, and the role of sympathetic nervous system that may mediate these sleep deprivation induced effects. METHODS The animals were randomized into four groups (n = 11 per group): Ischemia- Reperfusion group (IR), Acute sleep deprivation group (SD), Control group for sleep deprivation (CON-SD) and Sympathectomy + ASD group (SYM-SD). In SD group, sleep deprivation paradigm was used 24 h prior to induction of ischemia/reperfusion. In SYM-SD group, the animals were chemically sympathectomized using 6-hydroxydopamine, 24 h before sleep deprivation. Then, the hearts of animals were perfused using Langendorff setup and were subjected to 30 min regional ischemia followed by 60 min of reperfusion. Throughout the experiment, the hearts were allowed to beat spontaneously and left ventricular developed pressure (LVDP) and rate pressure product (RPP) were recorded. At the end of study, infarct size and percentage of the area at risk were determined. RESULTS We found that SD increased LVDP and RPP, while reducing the myocardial infarct size. Moreover, sympathectomy reversed SD induced reduction in infarct size and showed no differences as compared to IR. CONCLUSION This study shows cardioprotective effects of acute sleep deprivation, which can be abolished by chemical sympathectomy in isolated hearts of rats.
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Affiliation(s)
- Zohreh Edalatyzadeh
- Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Marjan Aghajani
- Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Department of Physiology, School of Medicine, Shahed University, Tehran, Iran
| | - Alireza Imani
- Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Occupational Sleep Research Center, Tehran University of Medical Sciences, Tehran, Iran.
| | - Mahdieh Faghihi
- Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Sahar Askari
- Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Samira Choopani
- Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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Adameova A, Shah AK, Dhalla NS. Role of Oxidative Stress in the Genesis of Ventricular Arrhythmias. Int J Mol Sci 2020; 21:ijms21124200. [PMID: 32545595 PMCID: PMC7349053 DOI: 10.3390/ijms21124200] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/05/2020] [Accepted: 06/10/2020] [Indexed: 12/11/2022] Open
Abstract
Ventricular arrhythmias, mainly lethal arrhythmias, such as ventricular tachycardia and fibrillation, may lead to sudden cardiac death. These are triggered as a result of cardiac injury due to chronic ischemia, acute myocardial infarction and various stressful conditions associated with increased levels of circulating catecholamines and angiotensin II. Several mechanisms have been proposed to underlie electrical instability of the heart promoting ventricular arrhythmias; however, oxidative stress which adversely affects ion homeostasis due to changes in the ion channel structure and function, seems to play a critical role in eliciting different types of ventricular arrhythmias. Prevention or mitigation of the severity of ventricular arrhythmias due to antioxidants has been indicated as the fundamental contribution in the field of preventive cardiology; however, novel interventions have to be developed for greater effectiveness and specificity in attenuating the adverse effects of oxidative stress. In this review, we have attempted to discuss proarrhythmic effects of oxidative stress differing in time and concentration dependence and highlight a molecular and cellular concept how it alters cardiac cell automaticity and conduction velocity sensitizing the probability of ventricular arrhythmias with resultant sudden cardiac death due to ischemic heart disease and other stressful situations. It is concluded that pharmacological approaches targeting multiple mechanisms besides oxidative stress might be more effective in the treatment of ventricular arrhythmias than current antiarrhythmic therapy.
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Affiliation(s)
- Adriana Adameova
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Comenius University in Bratislava, and Center of Experimental Medicine, Slovak Academy of Sciences, Institute for Heart Research, Odbojarov 10, 83232 Bratislava, Slovakia
- Correspondence:
| | - Anureet K. Shah
- Department of Kinesiology, Nutrition and Food Science, California State University, Los Angeles, CA 90032, USA;
| | - Naranjan S. Dhalla
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, and Department of Physiology & Pathophysiology, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB R3E 0W2, Canada;
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Imani A, Parsa H, Chookalaei LG, Rakhshan K, Golnazari M, Faghihi M. Acute Physical Stress Preconditions the Heart Against Ischemia/Reperfusion Injury Through Activation of Sympathetic Nervous System. Arq Bras Cardiol 2019; 113:401-408. [PMID: 31621780 PMCID: PMC6882406 DOI: 10.5935/abc.20190189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 10/16/2018] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Stress is defined as a complicated state that related to homeostasis disturbances, over-activity of the sympathetic nervous system and hypothalamus-pituitary-adrenal axis responses. Cardiac preconditioning reduces myocardial damages. OBJECTIVE This study was designed to assess the cardioprotective effects of acute physical stress against ischemia/reperfusion (I/R) injury through the activation of the sympathetic nervous system. METHODS Thirty-two male Wistar rats were divided into four groups; (1) IR (n = 8): rats underwent I/R, (2) Acute stress (St+IR) (n = 8): physical stress induced 1-hour before I/R, (3) Sympathectomy (Symp+IR) (n = 8): chemical sympathectomy was done 24-hours before I/R and (4) Sympathectomy- physical stress (Symp+St+IR) (n = 8): chemical sympathectomy induced before physical stress and I/R. Chemical sympathectomy was performed using 6-hydroxydopamine (100 mg/kg, sc). Then, the hearts isolated and located in the Langendorff apparatus to induce 30 minutes ischemia followed by 120 minutes reperfusion. The coronary flows, hemodynamic parameters, infarct size, corticosterone level in serum were investigated. P < 0.05 demonstrated significance. RESULTS Physical stress prior to I/R could improve left ventricular developed pressure (LVDP) and rate product pressure (RPP) of the heart respectively, (63 ± 2 versus 42 ± 1.2, p < 0.05, 70 ± 2 versus 43 ± 2.6, p < 0.05) and reduces infarct size (22.16 ± 1.3 versus 32 ± 1.4, p < 0.05) when compared with the I/R alone. Chemical sympathectomy before physical stress eliminated the protective effect of physical stress on I/R-induced cardiac damages (RPP: 21 ± 6.6 versus 63 ± 2, p < 0.01) (LVDP: 38 ± 4.5 versus 43 ± 2.6, p < 0.01) (infarct size: 35 ± 3.1 versus 22.16 ± 1.3, p < 0.01). CONCLUSION Findings indicate that acute physical stress can act as a preconditional stimulator and probably, the presence of sympathetic nervous system is necessary.
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Affiliation(s)
- Alireza Imani
- Department of physiology - School of Medicine - Tehran University of Medical Sciences, Tehran - Iran.,Occupational Sleep Research Center - Baharloo Hospital - Tehran University of Medical Sciences, Tehran - Iran
| | - Hoda Parsa
- Department of physiology - School of Medicine - Tehran University of Medical Sciences, Tehran - Iran
| | - Leila Gholami Chookalaei
- Department of physiology - School of Medicine - Tehran University of Medical Sciences, Tehran - Iran
| | - Kamran Rakhshan
- Department of physiology - School of Medicine - Iran University of Medical Sciences, Tehran - Iran
| | - Masoomeh Golnazari
- Biology Department - Basic Sciences faculty - Hamedan Branch of Islamic Azad University, Hamedan - Iran
| | - Mahdieh Faghihi
- Department of physiology - School of Medicine - Tehran University of Medical Sciences, Tehran - Iran
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Nazari A, Sedighi M, Dalvand P, Azizi Y, Moghimian M, Boroujeni SN. Late cardiac perconditioning by phenylephrine in an isolated rat heart model is mediated by mitochondrial potassium channels. BRAZ J PHARM SCI 2019. [DOI: 10.1590/s2175-97902019000218075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Hundahl LA, Tfelt-Hansen J, Jespersen T. Rat Models of Ventricular Fibrillation Following Acute Myocardial Infarction. J Cardiovasc Pharmacol Ther 2017; 22:514-528. [PMID: 28381093 DOI: 10.1177/1074248417702894] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A number of animal models have been designed in order to unravel the underlying mechanisms of acute ischemia-induced arrhythmias and to test compounds and interventions for antiarrhythmic therapy. This is important as acute myocardial infarction (AMI) continues to be the major cause of sudden cardiac death, and we are yet to discover safe and effective treatments of the lethal arrhythmias occurring in the acute setting. Animal models therefore continue to be relevant for our understanding and treatment of acute ischemic arrhythmias. This review discusses the applicability of the rat as a model for ventricular arrhythmias occurring during the acute phase of AMI. It provides a description of models developed, advantages and disadvantages of rats, as well as an overview of the most important interventions investigated and the relevance for human pathophysiology.
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Affiliation(s)
- Laura A Hundahl
- 1 Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jacob Tfelt-Hansen
- 2 Department of Cardiology, Heart Centre, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Thomas Jespersen
- 1 Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Bian B, Yu X, Wang Q, Teng T, Nie J. Atorvastatin protects myocardium against ischemia-reperfusion arrhythmia by increasing Connexin 43 expression: A rat model. Eur J Pharmacol 2015; 768:13-20. [PMID: 26386290 DOI: 10.1016/j.ejphar.2015.09.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 09/14/2015] [Accepted: 09/15/2015] [Indexed: 12/21/2022]
Abstract
Atorvastatin has protective effects against myocardial ischemia-reperfusion injuries and ischemia-reperfusion arrhythmia. This study was designed to investigate whether atorvastatin is able to protect against myocardial ischemia-reperfusion injury by enhancing the expression of Connexin 43 (Cx43) via the activation of the phosphatidylinositol-3-kinase (PI3K)/Akt pathway and mitochondrial ATP-sensitive potassium (K(ATP)) channels. Isolated perfused rat hearts were treated with classic ischemia postconditioning (IPOST), atorvastatin, and atorvastatin combined with inhibitor of PI3K and K(ATP) channels, respectively, after 30min of LAD ischemia and then subjected to reperfusion for 120min. The QRS duration and the ischemia-reperfusion ventricular arrhythmia were assessed. The lactate dehydrogenase (LDH) and creatine kinase isoenzyme (CK-MB) levels were measured and the Cx43 expression was assessed by immunoblotting and immunohistochemistry. After 120min of reperfusion, atorvastatin and IPOST significantly decreased the QRS duration and inhibited ventricular arrhythmia. They also decreased the levels of LDH and CK-MB. Meanwhile, atorvastatin and IPOST also significantly enhanced the Cx43 expression and the phosphorylation of Cx43. Such protective effects were abolished in the presence of the inhibitor of PI3K or the inhibitor of mitochondrial K(ATP) channels. This study suggests that atorvastatin protected against myocardial ischemia-reperfusion injury and enhanced the expression of Cx43 by activating the PI3K/Akt pathway and mitochondrial K(ATP) channels.
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Affiliation(s)
- Bo Bian
- Cardiology Department, Tianjin Medical University General Hospital, Tianjin, China
| | - Xuefang Yu
- Cardiology Department, Tianjin Medical University General Hospital, Tianjin, China.
| | - Qing Wang
- Cardiology Department, Tianjin Medical University General Hospital, Tianjin, China
| | - Tianming Teng
- Cardiology Department, Tianjin Medical University General Hospital, Tianjin, China
| | - Jing Nie
- Cardiology Department, Tianjin Medical University General Hospital, Tianjin, China
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Han Y, Guo Z, Wang LL, Zhang LZ, Yao TP. Antagonism of endogenous nociceptin/orphanin FQ inhibits infarction-associated ventricular arrhythmias via PKC-dependent mechanism in rats. Br J Pharmacol 2014; 170:614-23. [PMID: 23869704 DOI: 10.1111/bph.12310] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 07/02/2013] [Accepted: 07/12/2013] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND AND PURPOSE Evidence indicates nociceptin/orphanin FQ (N/OFQ) may participate in the pathology of cardiac arrhythmias associated with myocardial infarction. But the role of N/OFQ in the arrhythmogenesis in acute myocardial infarction is unclear. The aim of this study was to investigate the effects of endogenous N/OFQ on infarction-associated arrhythmias. EXPERIMENTAL APPROACH The expression of N/OFQ, PKC activity and ventricular arrhythmias in presence and absence of UFP-101, a specific antagonist of N/OFQ receptor, were examined following permanent coronary artery occlusion in anaesthetized rats. The effect of N/OFQ on action potential duration was examined in isolated rat cardiomyocytes. KEY RESULTS It was observed that N/OFQ was increased by 41% in the myocardium after coronary artery occlusion (P < 0.01 vs. control). Pretreatment with UFP-101 (10(-7) mol·kg(-1) , i.v.) reduced the incidence of ventricular ectopic beats by 70% and ventricular tachycardia by 51% respectively (all P < 0.05 vs. control). Meanwhile, PKC activity was elevated in the rats treated with UFP-101 (by 35%, P < 0.05 vs. control). A selective PKC inhibitor, calphostin C, completely abolished the anti-arrhythmic effects of UFP-101 (P < 0.01). N/OFQ (at 10(-11) , 10(-9) and 1 × 10(-7) mol·L(-1) ) shortened the action potential duration by 3% (P > 0.05), 10% (P < 0.05) and 22% (P < 0.01), respectively, via N/OFQ receptor. CONCLUSIONS AND IMPLICATIONS Antagonism of endogenous N/OFQ produces anti-arrhythmic effects on ventricular arrhythmias in acute myocardial infarction, possibly via modulating PKC activity and action potential of myocytes.
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Affiliation(s)
- Y Han
- Department of Anesthesiology, Shanxi Medical University, Second Hospital of Shanxi Medical University, Taiyuan, China
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O'Connell TD, Jensen BC, Baker AJ, Simpson PC. Cardiac alpha1-adrenergic receptors: novel aspects of expression, signaling mechanisms, physiologic function, and clinical importance. Pharmacol Rev 2013; 66:308-33. [PMID: 24368739 DOI: 10.1124/pr.112.007203] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Adrenergic receptors (AR) are G-protein-coupled receptors (GPCRs) that have a crucial role in cardiac physiology in health and disease. Alpha1-ARs signal through Gαq, and signaling through Gq, for example, by endothelin and angiotensin receptors, is thought to be detrimental to the heart. In contrast, cardiac alpha1-ARs mediate important protective and adaptive functions in the heart, although alpha1-ARs are only a minor fraction of total cardiac ARs. Cardiac alpha1-ARs activate pleiotropic downstream signaling to prevent pathologic remodeling in heart failure. Mechanisms defined in animal and cell models include activation of adaptive hypertrophy, prevention of cardiac myocyte death, augmentation of contractility, and induction of ischemic preconditioning. Surprisingly, at the molecular level, alpha1-ARs localize to and signal at the nucleus in cardiac myocytes, and, unlike most GPCRs, activate "inside-out" signaling to cause cardioprotection. Contrary to past opinion, human cardiac alpha1-AR expression is similar to that in the mouse, where alpha1-AR effects are seen most convincingly in knockout models. Human clinical studies show that alpha1-blockade worsens heart failure in hypertension and does not improve outcomes in heart failure, implying a cardioprotective role for human alpha1-ARs. In summary, these findings identify novel functional and mechanistic aspects of cardiac alpha1-AR function and suggest that activation of cardiac alpha1-AR might be a viable therapeutic strategy in heart failure.
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Affiliation(s)
- Timothy D O'Connell
- VA Medical Center (111-C-8), 4150 Clement St., San Francisco, CA 94121. ; or Dr. Timothy D. O'Connell, E-mail:
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Wang LL, Han Y, Guo Z, Han SQ, Liu T. Esmolol activates endogenous neurokinin activity inhibiting infarction-induced arrhythmias in rats: Novel mechanisms of anti-arrhythmia. ACTA ACUST UNITED AC 2013; 186:116-22. [DOI: 10.1016/j.regpep.2013.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 07/26/2013] [Accepted: 08/13/2013] [Indexed: 10/26/2022]
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Wang X, Wang X, Gu Y, Wang T, Huang C. Wenxin Keli attenuates ischemia-induced ventricular arrhythmias in rats: Involvement of L‑type calcium and transient outward potassium currents. Mol Med Rep 2012; 7:519-24. [PMID: 23174802 DOI: 10.3892/mmr.2012.1195] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 11/08/2012] [Indexed: 11/06/2022] Open
Abstract
Wenxin Keli is the first state‑sanctioned traditional Chinese medicine (TCM)-based antiarrhythmic drug. The present study aimed to examine whether long‑term treatment with Wenxin Keli reduces ischemia‑induced ventricular arrhythmias in rats in vivo, and if so, which mechanisms are involved. Male rats were treated with either saline (control group) or Wenxin Keli for 3 weeks and were subjected to myocardial ischemia for 30 min with assessment of the resulting ventricular arrhythmias. The L‑type calcium current (ICa,L) and transient outward potassium current (Ito) were measured by the patch clamp technique in normal rat cardiac ventricular myocytes. During the 30‑min ischemia, Wenxin Keli significantly reduced the incidence of ventricular fibrillation (VF) (P<0.05). The number of ventricular tachycardia (VT)+VF episodes and the severity of arrhythmias were significantly reduced by Wenxin Keli administration compared to the control group (P<0.05). In addition, Wenxin Keli inhibited ICa,L and Ito in a concentration‑dependent manner. These results suggest that long‑term treatment with Wenxin Keli may attenuate ischemia‑induced ventricular arrhythmias in rats and that ICa,L and Ito may be involved in this attenuation.
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Affiliation(s)
- Xi Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, P.R. China
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Role of sympathetic nervous system in myocardial ischemia injury: Beneficial or deleterious? Int J Cardiol 2012; 157:269. [DOI: 10.1016/j.ijcard.2012.03.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 03/03/2012] [Indexed: 11/23/2022]
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Nazari A, Sadr SS, Faghihi M, Imani A, Moghimian M. The cardioprotective effect of different doses of vasopressin (AVP) against ischemia-reperfusion injuries in the anesthetized rat heart. Peptides 2011; 32:2459-66. [PMID: 22079221 DOI: 10.1016/j.peptides.2011.10.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2011] [Revised: 10/24/2011] [Accepted: 10/24/2011] [Indexed: 11/22/2022]
Abstract
The aim of the present study was to investigate the protective effect of various doses of exogenous vasopressin (AVP) against ischemia-reperfusion injury in anesthetized rat heart. Anesthetized rats were randomly divided into seven groups (n=4-13) and all of them subjected to prolonged 30 min regional ischemia and 120 min reperfusion. Group I served as saline control with ischemia, in treatment groups II, III, IV and V, respectively different doses of AVP (0.015, 0.03, 0.06 and 1.2 μg/rat) were infused within 10 min prior to ischemia, in group VI, an AVP-selective V1 receptor antagonist (SR49059, 1mg/kg, i.v.) was administrated prior to effective dose of AVP injection and in group VII, SR49059 (1 mg/kg, i.v.) was only administrated prior to ischemia. Various doses of AVP significantly prevented the decrease in heart rate (HR) at the end of reperfusion compared to their baseline and decreased infarct size, biochemical parameters [LDH (lactate dehydrogenase), CK-MB (creatine kinase-MB) and MDA (malondialdehyde) plasma levels], severity and incidence of ventricular arrhythmia, episodes and duration of ventricular tachycardia (VT) as compared to control group. Blockade of V1 receptors by SR49059 attenuated the cardioprotective effect of AVP on ventricular arrhythmias and biochemical parameters, but partially returned infarct size to control. AVP 0.03 μg/rat was known as effective dose. Our results showed that AVP owns a cardioprotective effect probably via V1 receptors on cardiac myocyte against ischemia/reperfusion injury in rat heart in vivo.
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Affiliation(s)
- Afshin Nazari
- Department of Physiology, School of Medicine, Tehran University of Medical Science, Tehran, Islamic Republic of Iran
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Noradrenaline Protects In Vivo Rat Heart Against Infarction and Ventricular Arrhythmias Via Nitric Oxide and Reactive Oxygen Species. J Surg Res 2011; 169:9-15. [DOI: 10.1016/j.jss.2009.10.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Revised: 10/05/2009] [Accepted: 10/15/2009] [Indexed: 11/17/2022]
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Akar FG, O'Rourke B. Mitochondria are sources of metabolic sink and arrhythmias. Pharmacol Ther 2011; 131:287-94. [PMID: 21513732 DOI: 10.1016/j.pharmthera.2011.04.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2011] [Accepted: 03/29/2011] [Indexed: 12/14/2022]
Abstract
Mitochondria have long been recognized for their central role in energy transduction and apoptosis. More recently, extensive work in multiple laboratories around the world has significantly extended the role of cardiac mitochondria from relatively static arbitrators of cell death and survival pathways to highly dynamic organelles that form interactive functional networks across cardiomyocytes. These coupled networks were shown to strongly affect cardiomyocyte responses to oxidative stress by modulating cell signaling pathways that strongly impact physiological properties. Of particular importance is the role of mitochondria in modulating key electrophysiological and calcium cycling properties in cardiomyocytes, either directly through activation of a myriad of mitochondrial ion channels or indirectly by affecting cell signaling cascades, ATP levels, and the over-all redox state of the cardiomyocyte. This important recognition has ushered a renewed interest in understanding, at a more fundamental level, the exact role that cardiac metabolism, in general and mitochondria, in particular, play in both health and disease. In this article, we provide an overview of recent advances in our growing understanding of the fundamental role that cardiac mitochondria play in the genesis of lethal arrhythmias.
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Affiliation(s)
- Fadi G Akar
- Cardiovascular Institute, Mount Sinai School of Medicine, New York, NY 10029, USA.
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17
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Hu X, Wu B, Wang X, Xu C, He B, Cui B, Lu Z, Jiang H. Minocycline attenuates ischemia-induced ventricular arrhythmias in rats. Eur J Pharmacol 2011; 654:274-9. [PMID: 21244851 DOI: 10.1016/j.ejphar.2011.01.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Revised: 12/04/2010] [Accepted: 01/04/2011] [Indexed: 11/30/2022]
Abstract
Minocycline has been shown to protect against myocardial ischemia-reperfusion injury. This study investigated the effects of minocycline on ischemia-induced ventricular arrhythmias in rats. Anesthetized male rats were once treated with minocycline (45mg/kg, i.p.) 1h before ischemia in the absence and/or presence of 2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride (LY294002, 0.3mg/kg, i.v., a PI3K inhibitor) and 5-hydroxydecanoic acid [5-HD, 10mg/kg, i.v., a specific inhibitor of mitochondrial ATP-sensitive potassium (K(ATP)) channels] which were once injected 10min before ischemia and then subjected to ischemia for 30min. Ventricular arrhythmias were assessed. L-type Ca(2+) current was measured by the patch-clamp technique. During the 30-minute ischemia, minocycline significantly reduced the incidence of ventricular fibrillation (VF) (P<0.05). The duration of VT+VF, the number of VT+VF episodes and the severity of arrhythmias were all significantly reduced by minocycline compared to those in myocardial ischemia group (P<0.05 for all). Administration of LY294002 or 5-HD abolished the protective effects of minocycline on VF incidence, the duration of VT+VF, the number of VT+VF episodes and the severity of arrhythmias (P<0.05 for all). In addition, minocycline inhibited L-type Ca(2+) currents of normal myocardial cell membrane in a dose-dependent manner. This study suggested that minocycline could attenuate ischemia-induced ventricular arrhythmias in rats in which PI3K/Akt signaling pathway, mitochondrial K(ATP) channels and L-type Ca(2+) channels may be involved.
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Affiliation(s)
- Xiaorong Hu
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute of Wuhan University, Wuhan, China
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18
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Jensen BC, O'Connell TD, Simpson PC. Alpha-1-adrenergic receptors: targets for agonist drugs to treat heart failure. J Mol Cell Cardiol 2010; 51:518-28. [PMID: 21118696 DOI: 10.1016/j.yjmcc.2010.11.014] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2010] [Accepted: 11/12/2010] [Indexed: 12/19/2022]
Abstract
Evidence from cell, animal, and human studies demonstrates that α1-adrenergic receptors mediate adaptive and protective effects in the heart. These effects may be particularly important in chronic heart failure, when catecholamine levels are elevated and β-adrenergic receptors are down-regulated and dysfunctional. This review summarizes these data and proposes that selectively activating α1-adrenergic receptors in the heart might represent a novel and effective way to treat heart failure. This article is part of a special issue entitled "Key Signaling Molecules in Hypertrophy and Heart Failure."
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Affiliation(s)
- Brian C Jensen
- Cardiology Division, VA Medical Center, San Francisco, CA, USA.
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Kmecova J, Klimas J. Heart rate correction of the QT duration in rats. Eur J Pharmacol 2010; 641:187-92. [DOI: 10.1016/j.ejphar.2010.05.038] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2010] [Revised: 05/14/2010] [Accepted: 05/28/2010] [Indexed: 11/16/2022]
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Abstract
Despite a high prevalence of sudden cardiac death throughout the world, the mechanisms that lead to ventricular arrhythmias are not fully understood. Over the last 20 years, a growing body of evidence indicates that cardiac mitochondria are involved in the genesis of arrhythmia. In this review, we have attempted to describe the role that mitochondria play in altering the heart's electrical function by introducing heterogeneity into the cardiac action potential. Specifically, we have focused on how the energetic status of the mitochondrial network can alter sarcolemmal potassium fluxes through ATP-sensitive potassium channels, creating a 'metabolic sink' for depolarizing wave-fronts and introducing conditions that favour catastrophic arrhythmia. Mechanisms by which mitochondria depolarize under conditions of oxidative stress are characterized, and the contributions of several mitochondrial ion channels to mitochondrial depolarization are presented. The inner membrane anion channel in particular opens upstream of other inner membrane channels during metabolic stress, and may be an effective target to prevent the metabolic oscillations that create action potential lability. Finally, we discuss therapeutic strategies that prevent arrhythmias by preserving mitochondrial membrane potential in the face of oxidative stress, supporting the notion that treatments aimed at cardiac mitochondria have significant potential in attenuating electrical dysfunction in the heart.
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Affiliation(s)
- David A Brown
- Department of Physiology, Brody School of Medicine and the East Carolina Heart Institute, East Carolina University, Room 6N-98, 600 Moye Blvd, Greenville, NC 27834, USA.
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Alizadeh AM, Faghihi M, Sadeghipour HR, Mohammadghasemi F, Imani A, Houshmand F, Khori V. Oxytocin protects rat heart against ischemia-reperfusion injury via pathway involving mitochondrial ATP-dependent potassium channel. Peptides 2010; 31:1341-5. [PMID: 20417240 DOI: 10.1016/j.peptides.2010.04.012] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Revised: 04/15/2010] [Accepted: 04/15/2010] [Indexed: 10/19/2022]
Abstract
Cardiac preconditioning represents the most potent and consistently reproducible method of rescuing heart tissue from undergoing irreversible ischemic damage. One of the major goals of the current cardiovascular research is to identify a reliable cardioprotective intervention that can salvage ischemic myocardium. The aim of the present study is to evaluate the oxytocin (OT)-induced cardioprotection and the signaling pathway involved with mitochondrial ATP-dependent potassium (mitoKATP) channel in the anesthetized rat heart. Animals were divided into six groups (n=6): (1) IR; hearts were subjected to 25 min ischemia and 120 min reperfusion, (2) OT; oxytocin was administered (0.03 microg/kg i.p.) 25 min prior to ischemia, (3) ATO+OT; atosiban (ATO) was used as an OT-selective receptor antagonist (1.5 microg/kg i.p.) 10 min prior to OT administration, (4) ATO; atosiban was used 35 min prior to ischemia, (5) 5HD+OT; 5-hydroxydecanoic acid (5HD) was used as a specific inhibitor of mitoKATP channel (10mg/kg i.v.) 10 min prior to OT administration, (6) 5HD; 5HD was used 35min prior to ischemia. Then infarct size, ventricular arrhythmia and creatine kinase-MB isoenzyme (CK-MB) plasma level were measured. Hemodynamic parameters were recorded throughout the experiment. OT administration significantly decreased infarct size, CK-MB plasma level, severity and incidence of ventricular arrhythmia as compared to IR group. Administration of atosiban and 5HD abolished the cardiopreconditioning effect of OT. This study demonstrates that cardioprotective effects of OT are mediated through opening the mitoKATP channels.
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Affiliation(s)
- Ali Mohammad Alizadeh
- Department of Physiology, School of Medicine, Tehran University of Medical Science, Enghelab Ave, Enghelab Squ, Tehran, Islamic Republic of Iran
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22
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Naderi R, Imani A, Faghihi M, Moghimian M. Phenylephrine induces early and late cardioprotection through mitochondrial permeability transition pore in the isolated rat heart. J Surg Res 2010; 164:e37-42. [PMID: 20850771 DOI: 10.1016/j.jss.2010.04.060] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Revised: 03/07/2010] [Accepted: 04/29/2010] [Indexed: 11/17/2022]
Abstract
BACKGROUND The aim of this study was to investigate the role of mitochondrial permeability transition pore (mPTP) in cardioprotection afforded by phenylephrine pretreatment in early and late phases. METHODS Rat hearts were isolated and perfused with Krebs buffer in Langendorff preparation and subjected to 30 min regional ischemia followed by 60 min of reperfusion. Phenylephrine as a selective α1-adrenoceptor agonist and atractyloside as a specific opener of the mPTP were used. Seven groups (n = 6) of rats were randomly studied: (I) control: surgical procedure was performed with no ischemia/reperfusion, (II) ischemia/reperfusion: hearts underwent regional ischemia/reperfusion, (III) early phenylephrine: phenylephrine (50 μM) was perfused for 5 min prior to ischemia/reperfusion, (IV) late phenylephrine: rats were treated with phenylephrine (10 mg/kg, i.p) 24 h prior to ischemia/reperfusion, (V) early phenylephrine+atractyloside: hearts were perfused with phenylephrine as in group III and then atractyloside (20 mM) 5 min before reperfusion for 20 min, (VI) late phenylephrine+atractyloside: hearts were treated with phenylephrine as in group IV and then received atractyloside (20 mM), 5 min before reperfusion for 20 min, (VII) atractyloside-IR group: hearts were perfused with atractyloside (20 mM) 5 min before reperfusion for 20 min. RESULTS Compared with ischemia/reperfusion group, perfusion of phenylephrine in early and late phases decreased myocardial infarct size (% of ischemia zone), reduced creatine kinase-MB (CK-MB) in the coronary effluent, and improved cardiac function. Administration of atractyloside abolished cardioprotective effects of phenylephrine in both early and late phases and returned infarct size, CK-MB and cardiac function to levels as seen in ischemia/reperfusion group. CONCLUSION These results suggest that administration of atractyloside as a specific opener of the mPTP abolishes phenylephrine-induced early and late cardioprotection in the isolated rat hearts.
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Affiliation(s)
- Roya Naderi
- Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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Naderi R, Imani A, Faghihi M. Phenylephrine produces late pharmacological preconditioning in the isolated rat heart. Eur J Pharmacol 2010; 627:203-8. [DOI: 10.1016/j.ejphar.2009.10.052] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2008] [Revised: 10/06/2009] [Accepted: 10/26/2009] [Indexed: 11/26/2022]
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Houshmand F, Faghihi M, Zahediasl S. Biphasic protective effect of oxytocin on cardiac ischemia/reperfusion injury in anaesthetized rats. Peptides 2009; 30:2301-8. [PMID: 19761809 DOI: 10.1016/j.peptides.2009.09.010] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Revised: 09/06/2009] [Accepted: 09/08/2009] [Indexed: 01/19/2023]
Abstract
Oxytocin (OT) is well known for its role in reproduction. However, evidence has emerged suggesting a role in cardiovascular system. The aim of this study was to investigate the cardioprotective effect of oxytocin on ischemia/reperfusion (I/R) injury in an in vivo rat. Myocardial ischemia, was surgically induced by means of left anterior descending coronary artery occlusion for 25 min followed by reperfusion for 120 min. Infarct size was evaluated using the staining agent 2,3,5-triphenyltetrazolium chloride. Creatine kinase-MB isoenzyme (CK-MB) and lactate dehydrogenase (LDH) levels in plasma were analyzed to assess the degree of cardiac injury. Intraperitoneal administration of OT 0.001, 0.01 and 0.1 microg significantly reduced infarct size, LDH and CK-MB levels as compared to control (I/R) group and it had a biphasic effect on the reduction of ischemia/reperfusion injury. This biphasic effect was revealed as a U-shaped curve in which efficacy was optimal between very low and very high doses. Furthermore there were no significant differences in mean arterial pressure or heart rate between the OT treatment groups and control group during I/R. Blockade of specific OT receptors by atosiban (10(-6)M) abolished or attenuated the effect of OT preconditioning. The result of this study shows that OT possess a dose-dependent cardioprotective effect against ischemia/reperfusion injury and so study of OT preconditioning may provide a new target site for therapeutic exploitation.
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Affiliation(s)
- Fariba Houshmand
- Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Islamic Republic of Iran
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25
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Gandhi C, Upaganalawar A, Balaraman R. Protection against in vivo focal myocardial ischemia/reperfusion injury-induced arrhythmias and apoptosis by hesperidin. Free Radic Res 2009; 43:817-27. [PMID: 19579067 DOI: 10.1080/10715760903071656] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Among the heart diseases, ischemia and reperfusion (I/R) induced arrhythmias contribute to episodes of sudden death. Cardiac arrhythmias during ischemia reperfusion are believed to be related to oxidative stress. Therefore, the aim of this study was to examine whether treatment with hesperidin alleviates arrhythmias and infarct size in experimentally-induced myocardial I/R injury using an in vivo rat model. In this study haemodynamics parameters, markers of inflammation, biomarkers of oxidative stress and tissue nitrite level and infarct size of the heart were estimated in various groups. I/R showed a significant decrease in tissue nitrite and antioxidant level and significant increase in arrhythmias, inflammation and myocardial cell apoptosis. Treatment with hesperidin showed a significant increase in tissue nitrite, antioxidant level and reduction in inflammation, arrhythmias and apoptosis. In conclusion, the protecting effect of hesperidin in I/R induced arrhythmias is due to reduction in inflammation and oxidative stress.
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Affiliation(s)
- Chintan Gandhi
- Pharmacy Department, Faculty of Technology and Engineering, M. S. University of Baroda, Kalabhavan, Gujarat, India.
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Maslov LN, Lishmanov YB, Oeltgen PR, Barzakh EI, Krylatov AV, Govindaswami M, Brown SA. Activation of peripheral delta2 opioid receptors increases cardiac tolerance to ischemia/reperfusion injury Involvement of protein kinase C, NO-synthase, KATP channels and the autonomic nervous system. Life Sci 2009; 84:657-63. [PMID: 19245818 DOI: 10.1016/j.lfs.2009.02.016] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Revised: 01/26/2009] [Accepted: 02/06/2009] [Indexed: 10/21/2022]
Abstract
AIMS This study aims to investigate the role of peripheral delta(2) opioid receptors in cardiac tolerance to ischemia/reperfusion injury and to examine the contribution of PKC, TK, K(ATP) channels and the autonomic nervous system in delta(2) cardioprotection. MAIN METHODS Deltorphin II and various inhibitors were administered in vivo prior to coronary artery occlusion and reperfusion in a rat model. The animals were monitored for the development of arrhythmias, infarct development and the effects of selected inhibitors. KEY FINDINGS Pretreatment with peripheral and delta(2) specific opioid receptor (OR) antagonists completely abolished the cardioprotective effects of deltorphin II. In contrast, the selective delta(1) OR antagonist 7-benzylidenenaltrexone (BNTX) had no effect. The protein kinase C (PKC) inhibitor chelerythrine and the NO-synthase inhibitor L-NAME (N-nitro-L-arginine methyl ester) also reversed both deltorphin II effects. The nonselective ATP-sensitive K+ (K(ATP)) channel inhibitor glibenclamide and the selective mitochondrial K(ATP) channel inhibitor 5-hydroxydecanoic acid only abolished the infarct-sparing effect of deltorphin II. Inhibition of tyrosine kinase (TK) with genistein, the ganglion blocker hexamethonium and the depletion of endogenous catecholamine storage with guanethidine reversed the antiarrhythmic action of deltorphin II but did not change its infarct-sparing action. SIGNIFICANCE The cardioprotective mechanism of deltorphin II is mediated via stimulation of peripheral delta(2) opioid receptors. PKC and NOS are involved in both its infarct-sparing and antiarrhythmic effects. Infarct-sparing is dependent upon mitochondrial K(ATP) channel activation while the antiarrhythmic effect is dependent upon TK activation. Endogenous catecholamine depletion reduced antiarrhythmic effects but did not alter the infarct-sparing effect of deltorphin II.
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Affiliation(s)
- Leonid N Maslov
- Laboratory of Experimental Cardiology, Research Institute of Cardiology, Siberian Branch, Russian Academy of Medical Sciences, Tomsk, Russia. :
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Jiang H, Hu X, Lu Z, Wen H, Zhao D, Tang Q, Yang B. Effects of Sympathetic Nerve Stimulation on Ischemia-induced Ventricular Arrhythmias by Modulating Connexin43 in Rats. Arch Med Res 2008; 39:647-54. [DOI: 10.1016/j.arcmed.2008.07.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Accepted: 07/14/2008] [Indexed: 11/25/2022]
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