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Sherbini AE, Liblik K, Lee J, Baranchuk A, Zhang S, El-Diasty M. Opioids-Induced Inhibition of HERG Ion Channels and Sudden Cardiac Death, A Systematic Review of Current Literature. Trends Cardiovasc Med 2023:S1050-1738(23)00040-3. [PMID: 37015297 DOI: 10.1016/j.tcm.2023.03.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/28/2023] [Accepted: 03/28/2023] [Indexed: 04/06/2023]
Abstract
BACKGROUND It is estimated that over 60 million individuals regularly use opioids globally, with opioid use disorder increasing substantially in the past decade. Several reports have linked sudden cardiac death, QTc prolongation, and other adverse cardiovascular outcomes with opioid use through their inhibitory effect on the human ether-a-go-go-related gene (HERG) ion channel. Therefore, understanding this underlying mechanism may be critical for risk prevention and management in prescribing opioids and treating patients with opioid dependency. AIM The present systematic review summarizes the current literature on the impact of opioids-induced inhibition of HERG channel function and its relationship with sudden cardiac death, QTc prolongation, and other cardiovascular adverse effects. METHODS A systematic review was conducted of the databases PubMed, EMBASE, Cochrane, and ClinicalTrials.gov of primary studies that reported the effects of opioids on HERG channel function and associated cardiovascular outcomes. RESULTS The search identified 1,546 studies, of which 12 were finally included for data extraction. Based on the current literature, methadone, oliceridine, l-α-acetylmethadol (LAAM), and fentanyl were found to inhibit the HERG channel function and were associated with QTc prolongation. However, other opioids such as morphine, codeine, tramadol, and buprenorphine were not associated with inhibition of HERG channels or QTc prolongation. Additional cardiac outcomes associated with opioid related HERG channels dysfunction included sudden cardiac death and torsade de pointes. CONCLUSION Our findings suggest that certain opioid consumption may result in the inhibition of HERG channels, subsequently prolonging the QTc interval and increasing patient susceptibility to sudden cardiac death.
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Affiliation(s)
- Adham El Sherbini
- Faculty of Health Sciences, Queen's University, Kingston, ON, Canada
| | - Kiera Liblik
- School of Medicine, Queen's University, Kingston, ON
| | - Junsu Lee
- Faculty of Health Sciences, Queen's University, Kingston, ON, Canada
| | - Adrian Baranchuk
- Division of Cardiology, Department of Medicine, Queen's University, Kingston, ON, Canada
| | - Shetuan Zhang
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Mohammad El-Diasty
- Division of Cardiac Surgery, Department of Surgery, Queen's University, Kingston, Ontario, Canada.
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Takahara A, Izawa S, Seki S, Aimoto M, Nagasawa Y. Cardiac Electropharmacological Effects of Antidiarrheal Drug Loperamide and Its Antidote Naloxone in Anesthetized Guinea Pigs. Biol Pharm Bull 2022; 45:542-546. [DOI: 10.1248/bpb.b22-00024] [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]
Affiliation(s)
- Akira Takahara
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University
| | - Sayaka Izawa
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University
| | - Shota Seki
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University
| | - Megumi Aimoto
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University
| | - Yoshinobu Nagasawa
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University
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Rodriguez RM, Tseng ZH, Montoy JCC, Repplinger D, Moffatt E, Addo N, Wang RC. NAloxone CARdiac Arrest Decision Instruments (NACARDI) for targeted antidotal therapy in occult opioid overdose precipitated cardiac arrest. Resuscitation 2021; 159:69-76. [PMID: 33359417 DOI: 10.1016/j.resuscitation.2020.12.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/29/2020] [Accepted: 12/03/2020] [Indexed: 01/15/2023]
Abstract
BACKGROUND We have recently demonstrated that a significant proportion of fatal out-of-hospital cardiac arrests (OHCAs) are precipitated by occult overdose, which could benefit from antidote therapy administered adjunctively with other cardiac resuscitation measures. We sought to develop simple decision instruments that EMS providers and other first responders can use to rapidly identify occult opioid overdose-associated OHCAs. METHODS We examined data from February 2011 through December 2017 in the Postmortem Systematic Investigation of Sudden Cardiac Death study, in which San Francisco (California) County EMS-attended OHCA deaths received autopsy and expert panel adjudication of cause of death. Using classification tree analyses, we derived highly sensitive and specific decision instruments that predicted our primary outcome of occult opioid OD-associated OHCA. We then calculated screening performance characteristics of these instruments. RESULTS Of 767 OHCA deaths, 80 (10.4%) were associated with occult opioid overdose. Of the eight models with 100% sensitivity for opioid overdose-associated cardiac arrest, the highest specificity model (23.4%, 95% confidence interval [CI] 20.3-26.7%) was age < 60 years OR race = black or non-Latinx white OR arrest in public place. The highest specificity instrument (96.3%, 95% CI 94.6-97.5%) consisting of age < 60 years AND race = black or non-Latinx white AND unwitnessed arrest AND female sex had 25% (95% CI 16-35.9%) sensitivity. CONCLUSIONS We have derived simple decision instruments that can identify patients whose OHCA precipitant was occult opioid overdose. These instruments may be used to guide selective administration of the antidote naloxone in OHCA resuscitations.
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Affiliation(s)
- Robert M Rodriguez
- Department of Emergency Medicine, University of California, San Francisco, United States.
| | - Zian H Tseng
- Section of Cardiac Electrophysiology, Division of Cardiology, Department of Medicine, University of California, San Francisco, United States
| | - Juan Carlos C Montoy
- Department of Emergency Medicine, University of California, San Francisco, United States
| | - Daniel Repplinger
- Department of Emergency Medicine, University of California, San Francisco, United States
| | - Ellen Moffatt
- Office of the Chief Medical Examiner, City and County of San Francisco, CA, United States
| | - Newton Addo
- Department of Emergency Medicine, University of California, San Francisco, United States
| | - Ralph C Wang
- Department of Emergency Medicine, University of California, San Francisco, United States
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Tran PN, Sheng J, Randolph AL, Baron CA, Thiebaud N, Ren M, Wu M, Johannesen L, Volpe DA, Patel D, Blinova K, Strauss DG, Wu WW. Mechanisms of QT prolongation by buprenorphine cannot be explained by direct hERG channel block. PLoS One 2020; 15:e0241362. [PMID: 33157550 PMCID: PMC7647070 DOI: 10.1371/journal.pone.0241362] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 10/13/2020] [Indexed: 12/04/2022] Open
Abstract
Buprenorphine is a μ-opioid receptor (MOR) partial agonist used to manage pain and addiction. QTC prolongation that crosses the 10 msec threshold of regulatory concern was observed at a supratherapeutic dose in two thorough QT studies for the transdermal buprenorphine product BUTRANS®. Because QTC prolongation can be associated with Torsades de Pointes (TdP), a rare but potentially fatal ventricular arrhythmia, these results have led to further investigation of the electrophysiological effects of buprenorphine. Drug-induced QTC prolongation and TdP are most commonly caused by acute inhibition of hERG current (IhERG) that contribute to the repolarizing phase of the ventricular action potentials (APs). Concomitant inhibition of inward late Na+ (INaL) and/or L-type Ca2+ (ICaL) current can offer some protection against proarrhythmia. Therefore, we characterized the effects of buprenorphine and its major metabolite norbuprenorphine on cardiac hERG, Ca2+, and Na+ ion channels, as well as cardiac APs. For comparison, methadone, a MOR agonist associated with QTC prolongation and high TdP risk, and naltrexone and naloxone, two opioid receptor antagonists, were also studied. Whole cell recordings were performed at 37°C on cells stably expressing hERG, CaV1.2, and NaV1.5 proteins. Microelectrode array (MEA) recordings were made on human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). The results showed that buprenorphine, norbuprenorphine, naltrexone, and naloxone had no effect on IhERG, ICaL, INaL, and peak Na+ current (INaP) at clinically relevant concentrations. In contrast, methadone inhibited IhERG, ICaL, and INaL. Experiments on iPSC-CMs showed a lack of effect for buprenorphine, norbuprenorphine, naltrexone, and naloxone, and delayed repolarization for methadone at clinically relevant concentrations. The mechanism of QTC prolongation is opioid moiety-specific. This remains undefined for buprenorphine, while for methadone it involves direct hERG channel block. There is no evidence that buprenorphine use is associated with TdP. Whether this lack of TdP risk can be generalized to other drugs with QTC prolongation not mediated by acute hERG channel block warrants further study.
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Affiliation(s)
- Phu N. Tran
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America
- Division of Immunology and Hematology Devices, Center for Devices and Radiological Health, US Food and Drug Administration. Silver Spring, Maryland, United States of America
| | - Jiansong Sheng
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America
- CiPALab, Gaithersburg, Maryland, United States of America
| | - Aaron L. Randolph
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Claudia Alvarez Baron
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Nicolas Thiebaud
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America
- Vertex Pharmaceuticals (Europe) Ltd, Abingdon, Oxfordshire, United Kingdom
| | - Ming Ren
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Min Wu
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America
- Division of Immunology and Hematology Devices, Center for Devices and Radiological Health, US Food and Drug Administration. Silver Spring, Maryland, United States of America
| | - Lars Johannesen
- Division of Cardiology and Nephrology, Office of Cardiology, Hematology, Endocrinology and Nephrology, Office of New Drugs, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Donna A. Volpe
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Dakshesh Patel
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, Maryland, United States of America
- Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ksenia Blinova
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - David G. Strauss
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Wendy W. Wu
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America
- * E-mail:
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Smith G, Beger S, Vadeboncoeur T, Chikani V, Walter F, Spaite DW, Bobrow B. Trends in overdose-related out-of-hospital cardiac arrest in Arizona. Resuscitation 2019; 134:122-126. [DOI: 10.1016/j.resuscitation.2018.10.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 10/06/2018] [Accepted: 10/15/2018] [Indexed: 02/02/2023]
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Martins HS, Koike MK, Velasco IT. Effects of terlipressin and naloxone compared with epinephrine in a rat model of asphyxia-induced cardiac arrest. Clinics (Sao Paulo) 2013; 68:1146-51. [PMID: 24037012 PMCID: PMC3752630 DOI: 10.6061/clinics/2013(08)14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 04/02/2013] [Indexed: 01/02/2023] Open
Abstract
OBJECTIVE To evaluate the hemodynamic and metabolic effects of terlipressin and naloxone in cardiac arrest. METHODS Cardiac arrest in rats was induced by asphyxia and maintained for 3.5 minutes. Animals were then resuscitated and randomized into one of six groups: placebo (n = 7), epinephrine (0.02 mg/kg; n = 7), naloxone (1 mg/kg; n = 7) or terlipressin, of which three different doses were tested: 50 µg/kg (TP50; n = 7), 100 µg/kg (TP100; n = 7) and 150 µg/kg (TP150; n = 7). Hemodynamic variables were measured at baseline and at 10 (T10), 20 (T20), 30 (T30), 45 (T45) and 60 (T60) minutes after cardiac arrest. Arterial blood samples were collected at T10, T30 and T60. RESULTS The mean arterial pressure values in the TP50 group were higher than those in the epinephrine group at T10 (165 vs. 112 mmHg), T20 (160 vs. 82 mmHg), T30 (143 vs. 66 mmHg), T45 (119 vs. 67 mmHg) and T60 (96 vs. 66.8 mmHg). The blood lactate level was lower in the naloxone group than in the epinephrine group at T10 (5.15 vs. 10.5 mmol/L), T30 (2.57 vs. 5.24 mmol/L) and T60 (2.1 vs. 4.1 mmol/L). CONCLUSIONS In this rat model of asphyxia-induced cardiac arrest, terlipressin and naloxone were effective vasopressors in cardiopulmonary resuscitation and presented better metabolic profiles than epinephrine. Terlipressin provided better hemodynamic stability than epinephrine.
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Affiliation(s)
- Herlon S Martins
- Faculdade de Medicina da Universidade de São Paulo, Department of Emergency Medicine, Research Laboratory, São PauloSP, Brazil
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Naloxone in cardiac arrest with suspected opioid overdoses. Resuscitation 2010; 81:42-6. [DOI: 10.1016/j.resuscitation.2009.09.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 09/08/2009] [Accepted: 09/18/2009] [Indexed: 11/20/2022]
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Liang JC, Huang AH, Wu JR, Liou SF, Dai ZK, Chen IJ, Yeh JL. Effects of labedipinedilol-A, third-generation dihydropyridine-type calcium blocker, on ouabain-induced arrhythmia. Drug Dev Res 2008. [DOI: 10.1002/ddr.20224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Should naloxone be prescribed in the ED management of patients with cardiac arrest? A case report and review of literature. Am J Emerg Med 2008; 26:113.e5-8. [DOI: 10.1016/j.ajem.2007.06.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2007] [Accepted: 06/22/2007] [Indexed: 11/17/2022] Open
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10
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Bébarová M, Matejovic P, Pásek M, Nováková M. Effect of haloperidol on transient outward potassium current in rat ventricular myocytes. Eur J Pharmacol 2006; 550:15-23. [PMID: 17045259 DOI: 10.1016/j.ejphar.2006.08.046] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2006] [Revised: 08/25/2006] [Accepted: 08/28/2006] [Indexed: 11/15/2022]
Abstract
Although sigma ligand haloperidol is known to affect repolarization in heart, its effect on potassium currents in cardiomyocytes has not yet been studied. We analyzed the effect of 1 micromol/l haloperidol on transient outward K(+) current (I(to)) in enzymatically isolated rat right ventricular cardiomyocytes using the whole-cell patch-clamp technique at room temperature. Haloperidol induced a decrease of amplitude and an acceleration of apparent inactivation of I(to), both in a voltage-independent manner. The averaged inhibition of I(to), evaluated as a change of its time integral, was 23.0+/-3.2% at stimulation frequency of 0.1 Hz. As a consequence of slow recovery of I(to) from the haloperidol-induced block (time constant 1482+/-783 ms), a cumulation of the block up to about 40% appeared at 3.3 Hz. We conclude that haloperidol causes a voltage-independent block of I(to) that cumulates at higher stimulation frequencies. Based on the computer reconstruction of experimental data, a block of I(to)-channels in both open and open-inactivated states appears to be likely mechanism of haloperidol-induced inhibition of I(to).
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Affiliation(s)
- Markéta Bébarová
- Department of Physiology, Faculty of Medicine, Masaryk University, Komenského nám. 2, 662 43 Brno, Czech Republic.
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Chen MH, Xie L, Liu TW, Song FQ, He T. Naloxone and epinephrine are equally effective for cardiopulmonary resuscitation in a rat asphyxia model. Acta Anaesthesiol Scand 2006; 50:1125-30. [PMID: 16987343 DOI: 10.1111/j.1399-6576.2006.01141.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND It is not known whether naloxone is as efficacious as epinephrine during cardiopulmonary resuscitation (CPR). The aim of the study was to compare the effects of naloxone and epinephrine on the outcomes of CPR following asphyxial cardiac arrest in rats. METHODS Cardiac arrest was induced with asphyxia by clamping the tracheal tubes. Twenty-four Sprague-Dawley rats were randomized prospectively into a saline group (treated with normal saline, 1 ml intravenously, n = 8), an epinephrine group (treated with epinephrine, 0.04 mg/kg intravenously, n = 8) or a naloxone group (treated with naloxone, 1 mg/kg intravenously, n = 8) in a blind fashion during resuscitation after asphyxial cardiac arrest. After 5 min of untreated cardiac arrest, conventional manual CPR was started and each drug was administered at the same time. RESULTS The rates of restoration of spontaneous circulation (ROSC) were one of eight (12.5%), seven of eight (87.5%) and seven of eight (87.5%) in the saline, epinephrine and naloxone groups, respectively. The rates of ROSC in the epinephrine and naloxone groups were equal and significantly greater than that in the saline group (P = 0.01 and P = 0.01, respectively). CONCLUSION The administration of naloxone or epinephrine alone may increase the resuscitation rate, and both drugs are equally effective for CPR in a rat asphyxia model. However, the mechanism by which naloxone produces its efficacy during CPR remains unclear and further experimentation will be necessary.
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Affiliation(s)
- M-H Chen
- Institute of Cardiovascular Diseases, First Affiliated Hospital of Guangxi Medical University, Nanning, China
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Mühlfeld C, Urru M, Rümelin R, Mirzaie M, Schöndube F, Richter J, Dörge H. Myocardial ischemia tolerance in the newborn rat involving opioid receptors and mitochondrial K+ channels. ACTA ACUST UNITED AC 2006; 288:297-303. [PMID: 16456873 DOI: 10.1002/ar.a.20315] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Neonatal rat hearts are more tolerant to ischemia compared to adult rat hearts. We hypothesized that opioid receptors and mitochondrial potassium channels are involved in the elevated ischemia tolerance of neonatal rats. Newborn rats were treated by an intraperitoneal injection with sodium chloride (placebo, Pla; n = 7), naloxone (Nal; n = 8), or K+ (ATP) channel blocker 5-hydroxydecanoate (HD; n = 8), or were left untreated (sham; n = 8). Thirty minutes after injection, the rats were sacrificed and hearts were arrested cardioplegically and fixed with aldehyde fixative 90 min after global ischemia at room temperature. For control, newborn rat hearts were fixed immediately after sacrifice. Ventricular tissue blocks were prepared for electron microscopy. Mitochondrial (volume-weighted mean volume of mitochondria) and cardiomyocyte volume (cellular edema index, CEI) were estimated to quantify the ischemic injury. Compared to control myocardium, CEI was increased by 244% +/- 39% in sham, 173% +/- 28% in Nal, 142% +/- 25% in HD, and 101% +/- 24% in Pla (P < 0.05 between groups). Volume-weighted mean volume of mitochondria was increased by 514% +/- 235% in sham, 341% +/- 110% in Nal, 458% +/- 149% in HD, and 175% +/- 70% in Pla. Differences between Pla and other groups were significant (P < 0.01 for all). No significant difference was observed between the other groups. Thus, ischemic injury was smallest with placebo, indicating a mechanism similar to preconditioning induced by the intraperitoneal injection. This response was attenuated by blockade of opioid receptors and mitochondrial potassium channels, suggesting their involvement in the elevated ischemia tolerance of newborn rat hearts.
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Affiliation(s)
- Christian Mühlfeld
- Division of Electron Microscopy, Department of Anatomy, University of Göttingen, Göttingen, Germany.
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Chang WL, Lee SS, Su MJ. Attenuation of post-ischemia reperfusion injury by thaliporphine and morphine in rat hearts. J Biomed Sci 2005; 12:611-9. [PMID: 16132108 DOI: 10.1007/s11373-005-7401-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2005] [Accepted: 05/17/2005] [Indexed: 10/25/2022] Open
Abstract
Pretreatment with thaliporphine before ischemia affords cardioprotective effects against reperfusion injury via antioxidant activity. This study evaluated whether thaliporphine administered at a certain period after myocardial ischemia conferred the same cardioprotection and assessed its possible new mechanism. The left main coronary artery of anaesthetized rats was occluded for 1 h and then reperfused for 2 h. Thaliporphine was administered at 10 min before reperfusion. Controls received saline only. Morphine, a nonselective opioid receptor agonist, was used as reference compound at 0.3 mg/kg. Thaliporphine at 0.05 and 0.5 mg/kg were found to reduce the infarct size. Recovery of cardiac function was higher in thaliporphine (0.5 mg/kg) group, as assessed by a significant improvement in the rates of pressure development (+dp/dt (max)). This compound also reduced plasma creatine kinase and cardiac MPO activity. These protective effects afforded by thaliporphine were diminished by the opioid receptor antagonists (naloxone or naltrexone) and by the mitochondrial K(ATP) blocker 5HD. In comparison, morphine reduced infarct size and MPO activity in the myocardium but produced slightly improvement in cardiac function after ischemia-reperfusion. These results demonstrate that reperfusion therapy with thaliporphine protect cardiac injury through further mechanism via activation of opioid receptor and opening of mitochondrial K(ATP) channels as morphine but with stronger activity.
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Affiliation(s)
- Wei-Luen Chang
- Institute of Pharmacology, College of Medicine, National Taiwan University, No. 1, Sec. 1, Jen-Ai Rd, Taipei, Taiwan
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Cao Z, Xiao F, Peng F, Jiang D, Mao X, Liu H, Li W, Hu D, Wang T. Expression, purification and functional characterization of a recombinant scorpion venom peptide BmTXKbeta. Peptides 2003; 24:187-92. [PMID: 12668201 DOI: 10.1016/s0196-9781(03)00025-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BmTXKbeta, a scorpion toxin isolated from the Chinese scorpion Buthus martensii Karsch (BmK), was expressed as a GST fusion protein in BL21 (DE3) strain. The recombinant GST-BmTXKbeta protein was purified by affinity chromatography. When treated with enterokinase, the GST-BmTXKbeta fusion protein released an approximate 6.5kDa protein which was the expected size for correctly processed. About 2mg purified recombinant BmTXKbeta protein (rBmTXKbeta) was produced from 1l bacterial culture, using this expression and purification system. The function of rBmTXKbeta was studied on the rabbit atrial myocyte by whole-cell patch clamp technique. The results showed that rBmTXKbeta inhibited the transient outward current (I(to)) of rabbit atrial myocyte with recovery after washout and the inhibition was concentration-dependent. The rBmTXKbeta prolonged the action potential duration of rabbit atrial myocyte in a concentration-dependent manner, whereas it did not affect the action potential amplitude.
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Affiliation(s)
- Zhijian Cao
- Department of Biotechnology, Institute of Virology, College of Life Science, Wuhan University, 430072, Wuhan, PR China
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Abstract
This paper is the twenty-first installment of our annual review of research concerning the opiate system. It summarizes papers published during 1998 that studied the behavioral effects of the opiate peptides and antagonists, excluding the purely analgesic effects, although stress-induced analgesia is included. The specific topics covered this year include stress; tolerance and dependence; eating and drinking; alcohol; gastrointestinal, renal, and hepatic function; mental illness and mood; learning, memory, and reward; cardiovascular responses; respiration and thermoregulation; seizures and other neurologic disorders; electrical-related activity; general activity and locomotion; sex, pregnancy, and development; immunologic responses; and other behaviors.
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Affiliation(s)
- A L Vaccarino
- Department of Psychology, University of New Orleans, LA 70148, USA.
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