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Eroglu TE, Barcella CA, Gerds TA, Kessing LV, Zylyftari N, Mohr GH, Kragholm K, Polcwiartek C, Wissenberg M, Folke F, Tan HL, Torp-Pedersen C, Gislason GH. Risk of out-of-hospital cardiac arrest in antidepressant drug users. Br J Clin Pharmacol 2022; 88:3162-3171. [PMID: 35001414 PMCID: PMC9303588 DOI: 10.1111/bcp.15224] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 11/29/2021] [Accepted: 12/24/2021] [Indexed: 11/22/2022] Open
Abstract
Conflicting results have been reported regarding the association between antidepressant use and out‐of‐hospital cardiac arrest (OHCA) risk. We investigated whether the use of antidepressants is associated with OHCA.
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Affiliation(s)
- Talip E Eroglu
- Department of Cardiology, Copenhagen University Hospital - Herlev and Gentofte, Copenhagen, Denmark.,Amsterdam UMC, Academic Medical Center, University of Amsterdam, Department of Experimental and Clinical Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands.,Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Carlo A Barcella
- Department of Cardiology, Copenhagen University Hospital - Herlev and Gentofte, Copenhagen, Denmark
| | - Thomas A Gerds
- The Danish Heart Foundation, Copenhagen, Denmark.,Department of Biostatistics, University of Copenhagen, Copenhagen, Denmark
| | - Lars Vedel Kessing
- Copenhagen Affective Disorder research Center (CADIC), Psychiatric Center Copenhagen, Copenhagen University Hospital, Copenhagen, Denmark.,Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Nertila Zylyftari
- Department of Cardiology, Copenhagen University Hospital - Herlev and Gentofte, Copenhagen, Denmark.,Department of Cardiology, Nordsjaellands Hospital, Hillerød, Denmark
| | - Grimur H Mohr
- Department of Cardiology, Copenhagen University Hospital - Herlev and Gentofte, Copenhagen, Denmark.,Mental Health Centre Glostrup, Copenhagen University Hospital, Copenhagen, Denmark
| | - Kristian Kragholm
- Copenhagen Affective Disorder research Center (CADIC), Psychiatric Center Copenhagen, Copenhagen University Hospital, Copenhagen, Denmark
| | - Christoffer Polcwiartek
- Copenhagen Affective Disorder research Center (CADIC), Psychiatric Center Copenhagen, Copenhagen University Hospital, Copenhagen, Denmark
| | - Mads Wissenberg
- Department of Cardiology, Copenhagen University Hospital - Herlev and Gentofte, Copenhagen, Denmark
| | - Fredrik Folke
- Department of Cardiology, Copenhagen University Hospital - Herlev and Gentofte, Copenhagen, Denmark.,Copenhagen University Hospital - Copenhagen Emergency Medical Services, Copenhagen, Denmark.,Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Hanno L Tan
- Amsterdam UMC, Academic Medical Center, University of Amsterdam, Department of Experimental and Clinical Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands.,Netherlands Heart Institute, Utrecht, The Netherlands
| | - Christian Torp-Pedersen
- Department of Cardiology, Aalborg University Hospital, Aalborg, Denmark.,Department of Cardiology, Nordsjaellands Hospital, Hillerød, Denmark
| | - Gunnar H Gislason
- Department of Cardiology, Copenhagen University Hospital - Herlev and Gentofte, Copenhagen, Denmark.,Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
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Lee HM, Chai OH, Hahn SJ, Choi BH. Antidepressant drug paroxetine blocks the open pore of Kv3.1 potassium channel. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2017; 22:71-80. [PMID: 29302214 PMCID: PMC5746514 DOI: 10.4196/kjpp.2018.22.1.71] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Accepted: 10/27/2017] [Indexed: 12/20/2022]
Abstract
In patients with epilepsy, depression is a common comorbidity but difficult to be treated because many antidepressants cause pro-convulsive effects. Thus, it is important to identify the risk of seizures associated with antidepressants. To determine whether paroxetine, a very potent selective serotonin reuptake inhibitor (SSRI), interacts with ion channels that modulate neuronal excitability, we examined the effects of paroxetine on Kv3.1 potassium channels, which contribute to highfrequency firing of interneurons, using the whole-cell patch-clamp technique. Kv3.1 channels were cloned from rat neurons and expressed in Chinese hamster ovary cells. Paroxetine reversibly reduced the amplitude of Kv3.1 current, with an IC50 value of 9.43 µM and a Hill coefficient of 1.43, and also accelerated the decay of Kv3.1 current. The paroxetine-induced inhibition of Kv3.1 channels was voltage-dependent even when the channels were fully open. The binding (k+1) and unbinding (k−1) rate constants for the paroxetine effect were 4.5 µM−1s−1 and 35.8 s−1, respectively, yielding a calculated KD value of 7.9 µM. The analyses of Kv3.1 tail current indicated that paroxetine did not affect ion selectivity and slowed its deactivation time course, resulting in a tail crossover phenomenon. Paroxetine inhibited Kv3.1 channels in a usedependent manner. Taken together, these results suggest that paroxetine blocks the open state of Kv3.1 channels. Given the role of Kv3.1 in fast spiking of interneurons, our data imply that the blockade of Kv3.1 by paroxetine might elevate epileptic activity of neural networks by interfering with repetitive firing of inhibitory neurons.
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Affiliation(s)
- Hyang Mi Lee
- Department of Pharmacology, Institute for Medical Science, Chonbuk National University Medical School, Jeonju 54097, Korea
| | - Ok Hee Chai
- Department of Anatomy, Institute for Medical Science, Chonbuk National University Medical School, Jeonju 54097, Korea
| | - Sang June Hahn
- Department of Physiology, Medical Research Center, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Bok Hee Choi
- Department of Pharmacology, Institute for Medical Science, Chonbuk National University Medical School, Jeonju 54097, Korea
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Sube R, Ertel EA. Cardiomyocytes Derived from Human Induced Pluripotent Stem Cells: An In-Vitro Model to Predict Cardiac Effects of Drugs. ACTA ACUST UNITED AC 2017. [DOI: 10.4236/jbise.2017.1011040] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Lee HM, Hahn SJ, Choi BH. Blockade of Kv1.5 by paroxetine, an antidepressant drug. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2015; 20:75-82. [PMID: 26807026 PMCID: PMC4722194 DOI: 10.4196/kjpp.2016.20.1.75] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Revised: 09/23/2015] [Accepted: 10/21/2015] [Indexed: 12/24/2022]
Abstract
Paroxetine, a selective serotonin reuptake inhibitor (SSRI), has been reported to have an effect on several ion channels including human ether-a-go-go-related gene in a SSRI-independent manner. These results suggest that paroxetine may cause side effects on cardiac system. In this study, we investigated the effect of paroxetine on Kv1.5, which is one of cardiac ion channels. The action of paroxetine on the cloned neuronal rat Kv1.5 channels stably expressed in Chinese hamster ovary cells was investigated using the whole-cell patch-clamp technique. Paroxetine reduced Kv1.5 whole-cell currents in a reversible concentration-dependent manner, with an IC 50 value and a Hill coefficient of 4.11 µM and 0.98, respectively. Paroxetine accelerated the decay rate of inactivation of Kv1.5 currents without modifying the kinetics of current activation. The inhibition increased steeply between -30 and 0 mV, which corresponded with the voltage range for channel opening. In the voltage range positive to 0 mV, inhibition displayed a weak voltage dependence, consistent with an electrical distance δ of 0.32. The binding (k+1) and unbinding (k-1) rate constants for paroxetine-induced block of Kv1.5 were 4.9 µM(-1)s(-1) and 16.1 s(-1), respectively. The theoretical K D value derived by k-1/k+1 yielded 3.3 µM. Paroxetine slowed the deactivation time course, resulting in a tail crossover phenomenon when the tail currents, recorded in the presence and absence of paroxetine, were superimposed. Inhibition of Kv1.5 by paroxetine was use-dependent. The present results suggest that paroxetine acts on Kv1.5 currents as an open-channel blocker.
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Affiliation(s)
- Hyang Mi Lee
- Department of Pharmacology, Institute for Medical Sciences, Chonbuk National University Medical School, Jeonju 54097, Korea
| | - Sang June Hahn
- Department of Physiology, Medical Research Center, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Bok Hee Choi
- Department of Pharmacology, Institute for Medical Sciences, Chonbuk National University Medical School, Jeonju 54097, Korea
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Abstract
Late I Na is an integral part of the sodium current, which persists long after the fast-inactivating component. The magnitude of the late I Na is relatively small in all species and in all types of cardiomyocytes as compared with the amplitude of the fast sodium current, but it contributes significantly to the shape and duration of the action potential. This late component had been shown to increase in several acquired or congenital conditions, including hypoxia, oxidative stress, and heart failure, or due to mutations in SCN5A, which encodes the α-subunit of the sodium channel, as well as in channel-interacting proteins, including multiple β subunits and anchoring proteins. Patients with enhanced late I Na exhibit the type-3 long QT syndrome (LQT3) characterized by high propensity for the life-threatening ventricular arrhythmias, such as Torsade de Pointes (TdP), as well as for atrial fibrillation. There are several distinct mechanisms of arrhythmogenesis due to abnormal late I Na, including abnormal automaticity, early and delayed after depolarization-induced triggered activity, and dramatic increase of ventricular dispersion of repolarization. Many local anesthetic and antiarrhythmic agents have a higher potency to block late I Na as compared with fast I Na. Several novel compounds, including ranolazine, GS-458967, and F15845, appear to be the most selective inhibitors of cardiac late I Na reported to date. Selective inhibition of late I Na is expected to be an effective strategy for correcting these acquired and congenital channelopathies.
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He FZ, McLeod HL, Zhang W. Current pharmacogenomic studies on hERG potassium channels. Trends Mol Med 2013; 19:227-38. [PMID: 23369369 DOI: 10.1016/j.molmed.2012.12.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 12/18/2012] [Accepted: 12/27/2012] [Indexed: 11/25/2022]
Abstract
Genetic polymorphisms in human ether-a-go-go-related gene (hERG) potassium channels are associated with many complex diseases and sensitivity to channel-related drugs. Genotypes may underlie different sensitivities to the same drug, and different drugs selectively repair the functional deficits caused by individual mutations. In fact, not all drugs that block hERG function have adverse effects as previously thought. This suggests that the severe adverse reactions observed clinically may only occur in subjects with a particular genotype, but to others may be safe. Similarly, a drug that is ineffective in one population may be both safe and effective in another. Therefore, detecting polymorphisms in KCNH2 encoding hERG1 is of great significance in guiding the prevention and treatment of related diseases, re-evaluating drug safety, and individualizing treatment. This article reviews current pharmacogenomic studies on hERG potassium channels to provide a reference for developing individualized treatments and evaluating their safety.
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Affiliation(s)
- Fa-Zhong He
- Pharmacogenetics Research Institute, Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha, Hunan 410078, PR China
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Ababneh D, Ritchie H, Webster WS. Antidepressants Cause Bradycardia and Heart Block in GD 13 Rat Embryos In Vitro. ACTA ACUST UNITED AC 2012; 95:184-93. [DOI: 10.1002/bdrb.21003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Deena Ababneh
- Department of Anatomy and Histology; Sydney Medical School; University of Sydney; Sydney; Australia
| | - Helen Ritchie
- Discipline of Biomedical Sciences,; Sydney Medical School; University of Sydney; Sydney; Australia
| | - William S. Webster
- Department of Anatomy and Histology; Sydney Medical School; University of Sydney; Sydney; Australia
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Kobayashi T, Washiyama K, Ikeda K. Inhibition of G protein-activated inwardly rectifying K+ channels by different classes of antidepressants. PLoS One 2011; 6:e28208. [PMID: 22164246 PMCID: PMC3229538 DOI: 10.1371/journal.pone.0028208] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 11/03/2011] [Indexed: 11/19/2022] Open
Abstract
Various antidepressants are commonly used for the treatment of depression and several other neuropsychiatric disorders. In addition to their primary effects on serotonergic or noradrenergic neurotransmitter systems, antidepressants have been shown to interact with several receptors and ion channels. However, the molecular mechanisms that underlie the effects of antidepressants have not yet been sufficiently clarified. G protein-activated inwardly rectifying K+ (GIRK, Kir3) channels play an important role in regulating neuronal excitability and heart rate, and GIRK channel modulation has been suggested to have therapeutic potential for several neuropsychiatric disorders and cardiac arrhythmias. In the present study, we investigated the effects of various classes of antidepressants on GIRK channels using the Xenopus oocyte expression assay. In oocytes injected with mRNA for GIRK1/GIRK2 or GIRK1/GIRK4 subunits, extracellular application of sertraline, duloxetine, and amoxapine effectively reduced GIRK currents, whereas nefazodone, venlafaxine, mianserin, and mirtazapine weakly inhibited GIRK currents even at toxic levels. The inhibitory effects were concentration-dependent, with various degrees of potency and effectiveness. Furthermore, the effects of sertraline were voltage-independent and time-independent during each voltage pulse, whereas the effects of duloxetine were voltage-dependent with weaker inhibition with negative membrane potentials and time-dependent with a gradual decrease in each voltage pulse. However, Kir2.1 channels were insensitive to all of the drugs. Moreover, the GIRK currents induced by ethanol were inhibited by sertraline but not by intracellularly applied sertraline. The present results suggest that GIRK channel inhibition may reveal a novel characteristic of the commonly used antidepressants, particularly sertraline, and contributes to some of the therapeutic effects and adverse effects.
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Affiliation(s)
- Toru Kobayashi
- Department of Project Programs, Center for Bioresource-based Researches, Brain Research Institute, Niigata University, Niigata, Japan.
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Hu C, Yan C, Lin J, Liu S, Li Y. Down-regulation of the human ether-a-go-go-related gene in rat cardiac hypertrophy. Am J Med Sci 2011; 341:119-25. [PMID: 21042170 DOI: 10.1097/maj.0b013e3181f73f81] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
INTRODUCTION Cardiac hypertrophy is a risk factor for QT prolongation and cardiac sudden death. In this study, the authors examined the expressional regulation on the rat human ether-a-go-go-related gene (HERG), which encodes a structural subunit of the rapid component of the delayed rectifier potassium current (I(Kr)), during myocardial hypertrophy using rat as a model system. METHODS Cardiac hypertrophy was established in Sprague-Dawley rats by coarctation of the abdominal aorta [left ventricular hypertrophy (LVH) group]. Sham-operated rats were defined as control group (Ctrl group). Hemodynamic, morphologic and histologic parameters were recorded 6 weeks after operation. In addition, the expression of HERG was also determined using a combination of real-time polymerase chain reaction, Western blot and immunohistochemical analyses. RESULTS Compared with the sham-operated Ctrl group, abdominal aortic coarctation induced LVH in the LVH group, as evidenced by significantly increased ratios of heart weight/left ventricular weight to body weight and enlarged left ventricular myocytes in the histologic sections. The hemodynamic profile revealed significant increases in heart rate and left ventricular end-diastolic pressure, as well as a decrease in the maximal rate of left ventricular pressure fall in the LVH rats, when compared with the Ctrl rats. Electrocardiograms showed prolonged QT and corrected QT intervals. On the molecular level, a significant reduction of HERG, messengerRNA and protein was observed in LVH group, which was inversely correlated with prolonged corrected QT (r = -0.842, P = 0.000). CONCLUSION The expressional down-regulation of HERG gene may constitute a novel mechanism for QT prolongation during cardiac hypertrophy.
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Affiliation(s)
- Chuangjia Hu
- Department of Cardiology, The First Affiliated Hospital, Shantou University Medical College, China
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Koseoglu Z, Kara B, Satar S. Bradycardia and hypotension in mianserin intoxication. Hum Exp Toxicol 2010; 29:887-8. [DOI: 10.1177/0960327110364639] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cardiotoxicity is an important adverse effect of tricyclic antidepressants. But cardiac side effects after intoxication with the tetracyclic mianserin are rare. In this paper, we describe a case in which bradycardia and hypotension occured due to mianserin overdose. A 37-year-old woman was admitted to the medical intensive care unit for self-poisoning with 30 tablets of 10 mg mianserin 2 hours before her admission. The patient denied taking any other drugs. Four hours after her admission, bradycardia and hypotension occurred and she began to suffer from giddiness. Atropine and theophylline were given. On the second and third day, her heart rate and blood pressure were normal. Based on this case, we estimate the probability of bradycardia and hypotension in mianserin intoxication and the significance of closely monitoring the patient.
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Affiliation(s)
- Zikret Koseoglu
- Emergency Department, Adana Numune Research and Education Hospital, Seyhan, Turkey
| | - Banu Kara
- Gastroenterology Department, Adana Numune Research and Education Hospital, Seyhan, Turkey,
| | - Salim Satar
- Emergency Department, Adana Numune Research and Education Hospital, Seyhan, Turkey
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Chen WH, Wang WY, Zhang J, Yang D, Wang YP. State-dependent blockade of human ether-a-go-go-related gene (hERG) K(+) channels by changrolin in stably transfected HEK293 cells. Acta Pharmacol Sin 2010; 31:915-22. [PMID: 20686516 DOI: 10.1038/aps.2010.84] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
AIM To study the effect of changrolin on the K(+) channels encoded by the human ether-a-go-go-related gene (hERG). METHODS hERG channels were heterologously stably expressed in human embryonic kidney 293 cells, and the hERG K(+) currents were recorded using a standard whole-cell patch-clamp technique. RESULTS Changrolin inhibited hERG channels in a concentration-dependent and reversible manner (IC(50)=18.23 mumol/L, 95% CI: 9.27-35.9 mumol/L; Hill coefficient=-0.9446). In addition, changrolin shifted the activation curve of hERG channels by 14.3+/-1.5 mV to more negative potentials (P<0.01, n=9) but did not significantly affect the steady-state inactivation of hERG (n=5, P>0.05). The relative block of hERG channels by changrolin was close to zero at the time point of channel opening by the depolarizing voltage step and quickly increased afterwards. The maximal block was achieved in the inactivated state, with no further development of the open channel block. In the "envelope of tails" experiments, the time constants of activation were found to be 287.8+/-46.2 ms and 174.2+/-18.4 ms, respectively, for the absence and presence of 30 mumol/L changrolin (P<0.05, n=7). The onset of inactivation was accelerated significantly by changrolin between -40 mV and +60 mV (P<0.05, n=7). CONCLUSION The results demonstrate that changrolin is a potent hERG blocker that preferentially binds to hERG channels in the open and inactivated states.
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Tjäderborn M, Aunes-Jansson M, Samuelsson E, Frison L, Johansson S, Berggren A, Edvardsson N. Prediction of drug-related morphological changes of the T wave. SCAND CARDIOVASC J 2010; 44:215-22. [PMID: 20429697 DOI: 10.3109/14017431003789892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVES To describe the characteristics of patients presenting with morphological T wave changes that lead to measurement difficulties, and to identify possible predictors of such changes at baseline and early after start of treatment. DESIGN ECGs from 145 patients receiving a combined potassium and sodium channel blocking agent for conversion of atrial fibrillation (AF), underwent semiautomatic analysis in a digitalized high-precision analysis program. In 15 patients, one or more ECGs were identified as difficult to interpret due to morphological T wave changes. They were compared with the 130 patients without such changes. RESULTS A history of cardiac failure (p=0.027), a smaller left atrial area (p=0.010) and a longer QT(tang) minus QT(top) interval (p<0.001) at baseline was significantly more frequent as compared to the controls. Identified patients also had somewhat longer baseline QT interval duration (median QT(cB) 432 vs. 408 ms, N.S.) and a larger proportion of them were females (47% vs. 27%, N.S.). After start of infusion the QT(cB) became significantly longer in identified patients than in controls (p=0.012). CONCLUSIONS Independent predictors of subsequent morphological changes were found at baseline and shortly after start of treatment, and may be of use to identify individuals with a reduced repolarization reserve.
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Abstract
AIM To examine whether selective serotonin reuptake inhibitor citalopram interacts with Kv1.5, one of the cardiovascular-specific Kv channel isoforms. METHODS The interaction between citalopram and Kv1.5 expressed in Chinese hamster ovary cells was studied using the whole-cell patch-clamp technique. RESULTS Citalopram reduced Kv1.5 whole-cell currents in a reversible concentration-dependent manner, with an IC(50) value and a Hill coefficient of 2.8+/-1.1 micromol/L and 0.8+/-0.3, respectively. Citalopram-induced inhibition of Kv1.5 is associated with time-dependent development of block without modifying the kinetics of current activation. The inhibition increased steeply between -30 and 0 mV, which corresponded with the voltage range for channel opening. In the voltage range positive to 0 mV, inhibition displayed an additional voltage dependence, consistent with an electrical distance delta of 0.19. Citalopram slowed the deactivation time course, resulting in a tail crossover phenomenon when the tail currents, recorded in the presence and absence of citalopram, were superimposed. Inhibition of Kv1.5 by citalopram was use-dependent. CONCLUSION The present results suggest that citalopram acts on Kv1.5 currents as an open-channel blocker, and much caution about arrhythmogenic risk is required when using citalopram in the treatment with depressed patients.
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Obers S, Staudacher I, Ficker E, Dennis A, Koschny R, Erdal H, Bloehs R, Kisselbach J, Karle CA, Schweizer PA, Katus HA, Thomas D. Multiple mechanisms of hERG liability: K+ current inhibition, disruption of protein trafficking, and apoptosis induced by amoxapine. Naunyn Schmiedebergs Arch Pharmacol 2010; 381:385-400. [PMID: 20229012 DOI: 10.1007/s00210-010-0496-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Accepted: 02/05/2010] [Indexed: 12/28/2022]
Abstract
The antidepressant amoxapine has been linked to cases of QT prolongation, acute heart failure, and sudden death. Inhibition of cardiac hERG (Kv11.1) potassium channels causes prolonged repolarization and is implicated in apoptosis. Apoptosis in association with amoxapine has not yet been reported. This study was designed to investigate amoxapine effects on hERG currents, hERG protein trafficking, and hERG-associated apoptosis in order to elucidate molecular mechanisms underlying cardiac side effects of the drug. hERG channels were expressed in Xenopus laevis oocytes and HEK 293 cells, and potassium currents were recorded using patch clamp and two-electrode voltage clamp electrophysiology. Protein trafficking was evaluated in HEK 293 cells by Western blot analysis, and cell viability was assessed in HEK cells by immunocytochemistry and colorimetric MTT assay. Amoxapine caused acute hERG blockade in oocytes (IC(50) = 21.6 microM) and in HEK 293 cells (IC(50) = 5.1 microM). Mutation of residues Y652 and F656 attenuated hERG blockade, suggesting drug binding to a receptor inside the channel pore. Channels were mainly blocked in open and inactivated states, and voltage dependence was observed with reduced inhibition at positive potentials. Amoxapine block was reverse frequency-dependent and caused accelerated and leftward-shifted inactivation. Furthermore, amoxapine application resulted in chronic reduction of hERG trafficking into the cell surface membrane (IC(50) = 15.3 microM). Finally, the antidepressant drug triggered apoptosis in cells expressing hERG channels. We provide evidence for triple mechanisms of hERG liability associated with amoxapine: (1) direct hERG current inhibition, (2) disruption of hERG protein trafficking, and (3) induction of apoptosis. Further experiments are required to validate a specific pro-apoptotic effect mediated through blockade of hERG channels.
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Affiliation(s)
- Sabrina Obers
- Department of Cardiology, Medical University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
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