1
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Yoosefian M, Tajadini B, Ahmadzadeh S, Zeraati-Moghani M, Pakdin-Parizi Z. Ethanol effects on L-type voltage-gated calcium channel performance. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2023.121634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
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2
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Jeong DJ, Kim KW, Suh BC. Dual regulation of Kv7.2/7.3 channels by long-chain n-alcohols. J Gen Physiol 2022; 155:213769. [PMID: 36534082 PMCID: PMC9767652 DOI: 10.1085/jgp.202213191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 10/31/2022] [Accepted: 12/02/2022] [Indexed: 12/23/2022] Open
Abstract
Normal alcohols (n-alcohols) can induce anesthetic effects by acting on neuronal ion channels. Recent studies have revealed the effects of n-alcohols on various ion channels; however, the underlying molecular mechanisms remain unclear. Here, we provide evidence that long-chain n-alcohols have dual effects on Kv7.2/7.3 channels, resulting in channel activation as the net effect. Using heterologous expression systems, we found that n-alcohols could differentially regulate the Kv7.2/7.3 channel depending on their chain length. Treatment with short-chain ethanol and propanol diminished Kv7.2/7.3 currents, whereas treatment with long-chain hexanol and octanol enhanced the currents. However, the long-chain alcohols failed to potentiate Kv7.2 currents pre-activated by retigabine. Instead, they inhibited the currents, similar to short-chain ethanol. The stimulatory effect of the long-chain n-alcohols was also converted into an inhibitory one in the mutant Kv7.2(W236L) channels, while the inhibitory effect of ethanol did not differ between wild-type Kv7.2 and mutant Kv7.2(W236L). The inhibition of currents by n-alcohols was also seen in Kv7.1 channel which does not have the tryptophan (W) residue in S5. These findings suggest that long-chain n-alcohols exhibit dual effects through independent working sites on the Kv7.2 channel. Finally, we confirmed that the hydroxyl group with a negative electrostatic potential surface is essential for the dual actions of n-alcohol. Together, our data suggest that long-chain n-alcohols regulate Kv7.2/7.3 channels by interacting with both stimulatory and inhibitory sites and that their stimulatory action depends on the conserved tryptophan 236 residue in S5 and could be important for triggering their anesthetic effects.
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Affiliation(s)
- Da-Jeong Jeong
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, Republic of Korea
| | - Kwon-Woo Kim
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, Republic of Korea
| | - Byung-Chang Suh
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, Republic of Korea,Correspondence to Byung-Chang Suh:
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3
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Chudzińska M, Wołowiec Ł, Banach J, Rogowicz D, Grześk G. Alcohol and Cardiovascular Diseases—Do the Consumption Pattern and Dose Make the Difference? J Cardiovasc Dev Dis 2022; 9:jcdd9100317. [PMID: 36286269 PMCID: PMC9603956 DOI: 10.3390/jcdd9100317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/06/2022] [Accepted: 09/17/2022] [Indexed: 11/22/2022] Open
Abstract
Excessive consumption of alcohol is not only a social problem, but it also significantly increases the morbidity and mortality rates of many societies. A correlation has been demonstrated between alcohol consumption and increased mortality from cancer, accidents and injuries, liver cirrhosis and other causes. Alcohol abuse increases the incidence of hemorrhagic stroke and the risk of ischemic stroke, induces serious arrhythmias, adversely affects blood pressure and damages the heart muscle. The dose and way of drinking alcohol play a crucial role in assessing whether this drink allows people to maintain health or whether it is a great health and social threat. The beneficial effects of low and moderate doses of alcohol on the occurrence of cardiovascular diseases have been shown in many population studies and meta-analyses in which the effect of U-shaped or J-shaped curves relating alcohol intake to cardiovascular mortality was observed, especially in ischemic heart disease. However, due to the fact that alcohol consumption is associated with many health hazards, it is not recommended to consume it as a preventive action of cardiovascular diseases. Moreover, recent studies suggest that association of low-to-moderate alcohol consumption with the reduction in cardiovascular risk is a result of lifestyle changes and that any reduction in alcohol consumption is in fact beneficial in terms of general health.
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Affiliation(s)
- Małgorzata Chudzińska
- Department of Nutrition and Dietetics, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Dębowa 3 Street, 85-626 Bydgoszcz, Poland
| | - Łukasz Wołowiec
- Department of Cardiology and Clinical Pharmacology, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Ujejskiego 75 Street, 85-168 Bydgoszcz, Poland
- Correspondence:
| | - Joanna Banach
- Department of Cardiology and Clinical Pharmacology, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Ujejskiego 75 Street, 85-168 Bydgoszcz, Poland
| | - Daniel Rogowicz
- Department of Cardiology and Clinical Pharmacology, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Ujejskiego 75 Street, 85-168 Bydgoszcz, Poland
| | - Grzegorz Grześk
- Department of Cardiology and Clinical Pharmacology, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Ujejskiego 75 Street, 85-168 Bydgoszcz, Poland
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4
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Ma T, Sato M, Komiya M, Kanomata K, Watanabe T, Feng X, Miyata R, Tadaki D, Hirose F, Tozawa Y, Hirano-Iwata A. Lateral voltage as a new input for artificial lipid bilayer systems. Faraday Discuss 2021; 233:244-256. [PMID: 34874047 DOI: 10.1039/d1fd00045d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this work, we propose lateral voltage as a new input for use in artificial lipid bilayer systems in addition to the commonly used transmembrane voltage. To apply a lateral voltage to bilayer lipid membranes, we fabricated electrode-equipped silicon and Teflon chips. The Si chips could be used for photodetector devices based on fullerene-doped lipid bilayers, and the Teflon chips were used in a study of the ion channel functions in the lipid bilayer. The findings indicate that the lateral voltage effectively regulates the transmembrane current, in both ion-channel-incorporated and fullerene-incorporated lipid bilayer systems, suggesting that the lateral voltage is a practicable and useful additional input for use in lipid bilayer systems.
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Affiliation(s)
- Teng Ma
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan. .,Core Research Cluster, Tohoku University, 2-1-1 Katahirano, Aoba-ku, Sendai 980-8577, Japan
| | - Madoka Sato
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.,Graduate School of Biomedical Engineering, Tohoku University, 6-6 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan
| | - Maki Komiya
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Kensaku Kanomata
- Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa 992-8510, Japan
| | - Takaya Watanabe
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.,Graduate School of Biomedical Engineering, Tohoku University, 6-6 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan
| | - Xingyao Feng
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Ryusuke Miyata
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.,Graduate School of Biomedical Engineering, Tohoku University, 6-6 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan
| | - Daisuke Tadaki
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Fumihiko Hirose
- Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa 992-8510, Japan
| | - Yuzuru Tozawa
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama-shi, Saitama 338-8570, Japan
| | - Ayumi Hirano-Iwata
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan. .,Core Research Cluster, Tohoku University, 2-1-1 Katahirano, Aoba-ku, Sendai 980-8577, Japan.,Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
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5
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Sutanto H, Cluitmans MJM, Dobrev D, Volders PGA, Bébarová M, Heijman J. Acute effects of alcohol on cardiac electrophysiology and arrhythmogenesis: Insights from multiscale in silico analyses. J Mol Cell Cardiol 2020; 146:69-83. [PMID: 32710981 DOI: 10.1016/j.yjmcc.2020.07.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 06/27/2020] [Accepted: 07/16/2020] [Indexed: 12/11/2022]
Abstract
Acute excessive ethyl alcohol (ethanol) consumption alters cardiac electrophysiology and can evoke cardiac arrhythmias, e.g., in 'holiday heart syndrome'. Ethanol acutely modulates numerous targets in cardiomyocytes, including ion channels, Ca2+-handling proteins and gap junctions. However, the mechanisms underlying ethanol-induced arrhythmogenesis remain incompletely understood and difficult to study experimentally due to the multiple electrophysiological targets involved and their potential interactions with preexisting electrophysiological or structural substrates. Here, we employed cellular- and tissue-level in-silico analyses to characterize the acute effects of ethanol on cardiac electrophysiology and arrhythmogenesis. Acute electrophysiological effects of ethanol were incorporated into human atrial and ventricular cardiomyocyte computer models: reduced INa, ICa,L, Ito, IKr and IKur, dual effects on IK1 and IK,ACh (inhibition at low and augmentation at high concentrations), and increased INCX and SR Ca2+ leak. Multiscale simulations in the absence or presence of preexistent atrial fibrillation or heart-failure-related remodeling demonstrated that low ethanol concentrations prolonged atrial action-potential duration (APD) without effects on ventricular APD. Conversely, high ethanol concentrations abbreviated atrial APD and prolonged ventricular APD. High ethanol concentrations promoted reentry in tissue simulations, but the extent of reentry promotion was dependent on the presence of altered intercellular coupling, and the degree, type, and pattern of fibrosis. Taken together, these data provide novel mechanistic insight into the potential proarrhythmic interactions between a preexisting substrate and acute changes in cardiac electrophysiology. In particular, acute ethanol exposure has concentration-dependent electrophysiological effects that differ between atria and ventricles, and between healthy and diseased hearts. Low concentrations of ethanol can have anti-fibrillatory effects in atria, whereas high concentrations promote the inducibility and maintenance of reentrant atrial and ventricular arrhythmias, supporting a role for limiting alcohol intake as part of cardiac arrhythmia management.
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Affiliation(s)
- Henry Sutanto
- Department of Cardiology, CARIM School for Cardiovascular Diseases, Maastricht University, the Netherlands
| | - Matthijs J M Cluitmans
- Department of Cardiology, CARIM School for Cardiovascular Diseases, Maastricht University, the Netherlands
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany
| | - Paul G A Volders
- Department of Cardiology, CARIM School for Cardiovascular Diseases, Maastricht University, the Netherlands
| | - Markéta Bébarová
- Department of Physiology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Jordi Heijman
- Department of Cardiology, CARIM School for Cardiovascular Diseases, Maastricht University, the Netherlands.
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6
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Monterrubio-Villar J, Llinares-Moya D. Brugada Phenocopy Induced by a Lethal Methanol Intoxication. Eur J Case Rep Intern Med 2020; 7:001374. [PMID: 32133307 PMCID: PMC7050964 DOI: 10.12890/2020_001374] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 11/23/2019] [Indexed: 11/27/2022] Open
Abstract
Brugada phenocopies (BrP) are clinical entities that present with an ECG pattern identical to either the type 1 or type 2 Brugada pattern without true congenital Brugada syndrome. This ECG pattern is associated with an identifiable condition and normalizes upon resolution or treatment of the underlying cause. We present a case of a 54-year-old man with extreme metabolic acidosis, hyperkalaemia and a Brugada type 1 ECG pattern in the setting of a suicidal methanol (MeOH) poisoning. Upon correction of these metabolic derangements with bicarbonate infusions and continuous veno-venous haemodiafiltration (CVVH), the Brugada type 1 ECG pattern normalized. Unfortunately, the patient developed signs of cerebral herniation followed by brain death and died on the first day of ICU admission.
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7
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Wu Q, Hayashi H, Hira D, Sonoda K, Ueshima S, Ohno S, Makiyama T, Terada T, Katsura T, Miura K, Horie M. Genetic variants of alcohol-metabolizing enzymes in Brugada syndrome: Insights into syncope after drinking alcohol. J Arrhythm 2019; 35:752-759. [PMID: 31624517 PMCID: PMC6787161 DOI: 10.1002/joa3.12227] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 07/31/2019] [Accepted: 08/06/2019] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Patients with Brugada syndrome (BrS) are known to have arrhythmic events after alcohol drinking and are recommended to avoid its excessive intake. Mechanisms underlying the alcohol-induced cardiac events are however unknown. This study aimed to test the hypothesis whether activity of alcohol-metabolizing enzymes determines fatal arrhythmic events after drinking alcohol. METHODS A total of 198 Japanese patients with BrS were enrolled in this study. These patients were classified into symptomatic (n = 90) and asymptomatic (n = 108) groups. The former was divided into an alcohol-related group (syncope after alcohol drinking, n = 16) and an alcohol-unrelated group (n = 74). Polymerase chain reaction was performed to determine genetic variants of genes encoding alcohol dehydrogenase 1B (ADH1B) and aldehyde dehydrogenase 2 (ALDH2). RESULTS The genotype distribution for ALDH2 was not significantly different between symptomatic and asymptomatic groups and between alcohol-related and alcohol-unrelated groups. The genotype distribution for ADH1B was not significantly different between symptomatic and asymptomatic groups, but the genotype ADH1B His/His was significantly more prevalent in the alcohol-related group than in the alcohol-unrelated group (81.3% vs 50%, P = .023). In multivariate logistic regression analysis, the genotype of ADH1B His/His was independently associated with syncope after alcohol drinking (odds ratio, 5.746; 95% confidence interval, 1.580-28.421; P = .007). CONCLUSIONS Arrhythmic events after alcohol drinking was associated with enhanced activity of alcohol-metabolizing enzyme ADH1B in our cohort of BrS. Therefore, the lifestyle change to avoid the excessive alcohol intake deserves attention.
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Affiliation(s)
- Qi Wu
- Department of Cardiovascular MedicineShiga University of Medical ScienceOhtsuJapan
| | - Hideki Hayashi
- Department of Cardiovascular MedicineShiga University of Medical ScienceOhtsuJapan
| | - Daiki Hira
- Department of PharmacyShiga University of Medical Science HospitalOhtsuJapan
- College of Pharmaceutical SciencesRitsumeikan UniversityKusatsuJapan
| | - Keiko Sonoda
- Department of Cardiovascular MedicineShiga University of Medical ScienceOhtsuJapan
- Department of Bioscience and GeneticsNational Cerebral and Cardiovascular CenterSuitaJapan
| | - Satoshi Ueshima
- College of Pharmaceutical SciencesRitsumeikan UniversityKusatsuJapan
| | - Seiko Ohno
- Department of Cardiovascular MedicineShiga University of Medical ScienceOhtsuJapan
- Department of Bioscience and GeneticsNational Cerebral and Cardiovascular CenterSuitaJapan
- Center for Epidemiologic Research in AsiaShiga University of Medical ScienceOhtsuJapan
| | - Takeru Makiyama
- Department of Cardiovascular and MedicineKyoto University Graduate School of MedicineKyotoJapan
| | - Tomohiro Terada
- Department of PharmacyShiga University of Medical Science HospitalOhtsuJapan
| | - Toshiya Katsura
- College of Pharmaceutical SciencesRitsumeikan UniversityKusatsuJapan
| | - Katsuyuki Miura
- Center for Epidemiologic Research in AsiaShiga University of Medical ScienceOhtsuJapan
- Department of Public HealthShiga University of Medical ScienceOhtsuJapan
| | - Minoru Horie
- Department of Cardiovascular MedicineShiga University of Medical ScienceOhtsuJapan
- Center for Epidemiologic Research in AsiaShiga University of Medical ScienceOhtsuJapan
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8
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Verkerk AO, Amin AS, Remme CA. Disease Modifiers of Inherited SCN5A Channelopathy. Front Cardiovasc Med 2018; 5:137. [PMID: 30327767 PMCID: PMC6174200 DOI: 10.3389/fcvm.2018.00137] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 09/10/2018] [Indexed: 12/19/2022] Open
Abstract
To date, a large number of mutations in SCN5A, the gene encoding the pore-forming α-subunit of the primary cardiac Na+ channel (NaV1.5), have been found in patients presenting with a wide range of ECG abnormalities and cardiac syndromes. Although these mutations all affect the same NaV1.5 channel, the associated cardiac syndromes each display distinct phenotypical and biophysical characteristics. Variable disease expressivity has also been reported, where one particular mutation in SCN5A may lead to either one particular symptom, a range of various clinical signs, or no symptoms at all, even within one single family. Additionally, disease severity may vary considerably between patients carrying the same mutation. The exact reasons are unknown, but evidence is increasing that various cardiac and non-cardiac conditions can influence the expressivity and severity of inherited SCN5A channelopathies. In this review, we provide a summary of identified disease entities caused by SCN5A mutations, and give an overview of co-morbidities and other (non)-genetic factors which may modify SCN5A channelopathies. A comprehensive knowledge of these modulatory factors is not only essential for a complete understanding of the diverse clinical phenotypes associated with SCN5A mutations, but also for successful development of effective risk stratification and (alternative) treatment paradigms.
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Affiliation(s)
- Arie O Verkerk
- Department of Clinical and Experimental Cardiology, Heart Centre, Academic Medical Center, Amsterdam, Netherlands.,Department of Medical Biology, Academic Medical Center, Amsterdam, Netherlands
| | - Ahmad S Amin
- Department of Clinical and Experimental Cardiology, Heart Centre, Academic Medical Center, Amsterdam, Netherlands
| | - Carol Ann Remme
- Department of Clinical and Experimental Cardiology, Heart Centre, Academic Medical Center, Amsterdam, Netherlands
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9
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Podgurskaya AD, Tsvelaya VA, Frolova SR, Kalita IY, Kudryashova NN, Agladze KI. Effect of heptanol and ethanol on excitation wave propagation in a neonatal rat ventricular myocyte monolayer. Toxicol In Vitro 2018; 51:136-144. [PMID: 29778719 DOI: 10.1016/j.tiv.2018.05.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Revised: 05/11/2018] [Accepted: 05/15/2018] [Indexed: 11/24/2022]
Abstract
In this work, the action of heptanol and ethanol was investigated in a two-dimensional (2D) model of cardiac tissue: the neonatal rat ventricular myocyte monolayer. Heptanol is known in electrophysiology as a gap junction uncoupler but may also inhibit voltage-gated ionic channels. Ethanol is often associated with the occurrence of arrhythmias. These substances influence sodium, calcium, and potassium channels, but the complete mechanism of action of heptanol and ethanol remains unknown. The optical mapping method was used to measure conduction velocities (CVs) in concentrations of 0.05-1.8 mM heptanol and 17-1342 mM ethanol. Heptanol was shown to slow the excitation wave significantly, and a mechanism that involves a simultaneous action on cell coupling and activation threshold was suggested. Whole-cell patch-clamp experiments showed inhibition of sodium and calcium currents at a concentration of 0.5 mM heptanol. Computer modeling was used to estimate the relative contribution of the cell uncoupling and activation threshold increase caused by heptanol. Unlike heptanol, ethanol slightly influenced the CV at clinically relevant concentrations. Additionally, the critical concentrations for re-entry formation in ethanol were determined.
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Affiliation(s)
- A D Podgurskaya
- The Laboratory of the Biophysics of Excitable Systems, Moscow Institute of Physics and Technology (State University), 9 Institutskiy per., Dolgoprudny, Moscow Region 141701, Russian Federation
| | - V A Tsvelaya
- The Laboratory of the Biophysics of Excitable Systems, Moscow Institute of Physics and Technology (State University), 9 Institutskiy per., Dolgoprudny, Moscow Region 141701, Russian Federation
| | - S R Frolova
- The Laboratory of the Biophysics of Excitable Systems, Moscow Institute of Physics and Technology (State University), 9 Institutskiy per., Dolgoprudny, Moscow Region 141701, Russian Federation
| | - I Y Kalita
- The Laboratory of the Biophysics of Excitable Systems, Moscow Institute of Physics and Technology (State University), 9 Institutskiy per., Dolgoprudny, Moscow Region 141701, Russian Federation
| | - N N Kudryashova
- The Laboratory of the Biophysics of Excitable Systems, Moscow Institute of Physics and Technology (State University), 9 Institutskiy per., Dolgoprudny, Moscow Region 141701, Russian Federation; Department of Physics and Astronomy, Ghent University, B-9000 Ghent, Belgium
| | - K I Agladze
- The Laboratory of the Biophysics of Excitable Systems, Moscow Institute of Physics and Technology (State University), 9 Institutskiy per., Dolgoprudny, Moscow Region 141701, Russian Federation.
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10
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Gervacio GG, Aherrera JAM, Sy RG, Abrahan Iv LL, Agbayani MJ, Punzalan FE, Llanes EJB, Reganit PFM, Sison OT, Tai ES, Velandria FV, Gumatay A, Castillo-Carandang NT. Cardiac events occurred commonly among apparently healthy Filipinos with the Brugada ECG pattern in the LIFECARE cohort. HEART ASIA 2018; 10:e010969. [PMID: 29868128 DOI: 10.1136/heartasia-2017-010969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Revised: 04/18/2018] [Accepted: 04/19/2018] [Indexed: 12/13/2022]
Abstract
Background Brugada syndrome is the mechanism for sudden unexplained death. The Brugada ECG pattern is found in 2% of Filipinos. There is a knowledge gap on the clinical outcome of these individuals. The clinical profile and 5-year cardiac event rate of individuals with the Brugada ECG pattern were determined in this cohort. Methods This is a sub-study of LIFECARE (Life Course Study in Cardiovascular Disease Epidemiology), a community based cohort enrolling healthy individuals 20 to 50 years old conducted in 2009-2010. ECGs of all enrollees were screened independently by three cardiologists. The prevalence of the coved Brugada ECG pattern was ascertained, and the 5-year cardiac event rate was determined among those individuals with this pattern. The participants were contacted to determine the occurrence of cardiac events, which included syncope, presyncope, seizures, cardiac arrest and unexplained vehicular accidents. Results A total of 3072 ECGs were reviewed, and 14 subjects (0.4%) with the coved Brugada ECG pattern were identified. Four had a cardiac event on follow-up at 5 years, but all remained alive. Most of these 14 coved Brugada individuals were healthy and asymptomatic at baseline. Conclusion Cardiac events occurred commonly among initially asymptomatic Filipinos with the coved Brugada ECG pattern. Such patients need to be followed up closely.
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Affiliation(s)
- Giselle G Gervacio
- Department of Medicine, University of the Philippines-Philippine General Hospital, Manila, Philippines
| | | | - Rody G Sy
- Department of Medicine, University of the Philippines-Philippine General Hospital, Manila, Philippines
| | - Lauro L Abrahan Iv
- Department of Medicine, University of the Philippines-Philippine General Hospital, Manila, Philippines
| | - Michael Joseph Agbayani
- Department of Medicine, University of the Philippines-Philippine General Hospital, Manila, Philippines
| | - Felix Eduardo Punzalan
- Department of Medicine, University of the Philippines-Philippine General Hospital, Manila, Philippines
| | - Elmer Jasper B Llanes
- Department of Medicine, University of the Philippines-Philippine General Hospital, Manila, Philippines
| | - Paul Ferdinand M Reganit
- Department of Medicine, University of the Philippines-Philippine General Hospital, Manila, Philippines
| | - Olivia T Sison
- Department of Clinical Epidemiology, University of the Philippines, Manila, Philippines
| | - E Shyong Tai
- Saw Swee Hock School of Public Health and Department of Medicine Yong Loo Lin School of Medicine, National University Health Care System Singapore, Singapore
| | - Felicidad V Velandria
- Department of Clinical Epidemiology, University of the Philippines, Manila, Philippines
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11
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Raheja H, Namana V, Chopra K, Sinha A, Gupta SS, Kamholz S, Moskovits N, Shani J, Hollander G. Electrocardiogram Changes with Acute Alcohol Intoxication: A Systematic Review. Open Cardiovasc Med J 2018. [PMID: 29541259 PMCID: PMC5838641 DOI: 10.2174/1874192401812010001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Background: Acute alcohol intoxication has been associated with cardiac arrhythmias but the electrocardiogram (ECG) changes associated with acute alcohol intoxication are not well defined in the literature. Objective: Highlight the best evidence regarding the ECG changes associated with acute alcohol intoxication in otherwise healthy patients and the pathophysiology of the changes. Methods: A literature search was carried out; 4 studies relating to ECG changes with acute alcohol intoxication were included in this review. Results: Of the total 141 patients included in the review, 90 (63.8%) patients had P-wave prolongation, 80 (56%) patients had QTc prolongation, 19 (13.5%) patients developed T-wave abnormalities, 10 (7%) patients had QRS complex prolongation, 3 (2.12%) patients developed ST-segment depressions. Conclusion: The most common ECG changes associated with acute alcohol intoxication are (in decreasing order of frequency) P-wave and QTc prolongation, followed by T-wave abnormalities and QRS complex prolongation. Mostly, these changes are completely reversible.
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Affiliation(s)
| | | | - Kirti Chopra
- Indiana University School of Dentistry, Indianapolis, USA
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12
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Morentin B, Callado LF, García-Hernández S, Bodegas A, Lucena J. The role of toxic substances in sudden cardiac death. ACTA ACUST UNITED AC 2018. [DOI: 10.1016/j.remle.2017.05.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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13
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Hung CL, Lai YJ, Chi PC, Chen LC, Tseng YM, Kuo JY, Lin CI, Chen YC, Lin SJ, Yeh HI. Dose-related ethanol intake, Cx43 and Nav1.5 remodeling: Exploring insights of altered ventricular conduction and QRS fragmentation in excessive alcohol users. J Mol Cell Cardiol 2017; 114:150-160. [PMID: 29097069 DOI: 10.1016/j.yjmcc.2017.10.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 10/05/2017] [Accepted: 10/27/2017] [Indexed: 02/05/2023]
Abstract
BACKGROUND Chronic, excessive ethanol intake has been linked with various electrical instabilities, conduction disturbances, and even sudden cardiac death, but the underlying cause for the latter is insufficiently delineated. METHODS We studied surface electrocardiography (ECG) in a community-dwelling cohort with moderate-to-heavy daily alcohol intake (grouped as >90g/day, ≤90g/day, and nonintake). RESULTS Compared with nonintake, heavier alcohol users showed markedly widened QRS duration and higher prevalence of QRS fragmentation (64.3%, 50.9%, and 33.7%, respectively, χ2 12.0, both p<0.05) on surface ECG across the 3 groups. These findings were successfully recapitulated in 14-week-old C57BL/6 mice that were chronically given a 4% or 6% alcohol diet and showed dose-related slower action potential upstroke, reduced resting membrane potential, and disorganized or decreased intraventricular conduction (all p<0.05). Immunodetection further revealed increased ventricular collagen I depots with Cx43 downregulation and remodeling, together with clustered and diminished membrane Nav1.5 distribution. Administration of Cx43 blocker (heptanol) and Nav1.5 inhibitor (tetrodotoxin) in the mice each attenuated the suppression ventricular conduction compared with nonintake mice (p<0.05). CONCLUSIONS Chronic excessive alcohol ingestion is associated with dose-related phenotypic intraventricular conduction disturbances and QRS fragmentation that can be recapitulated in mice. The mechanisms may involve suppressed gap junction and sodium channel functions, together with enhanced cardiac fibrosis that may contribute to arrhythmogenesis.
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Affiliation(s)
- Chung-Lieh Hung
- Department of Medicine, MacKay Medical College, New Taipei City, Taiwan; Division of Cardiology, Department of Internal Medicine, National Yang-Ming University, Taipei, Taiwan; Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan; Cardiovascular Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Yu-Jun Lai
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Po-Ching Chi
- Department of Medicine, MacKay Medical College, New Taipei City, Taiwan; Division of Cardiology, Department of Internal Medicine, National Yang-Ming University, Taipei, Taiwan; Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Liang-Chia Chen
- Department of Mechanical Engineering, National Taiwan University, Taipei, Taiwan
| | - Ya-Ming Tseng
- Division of Cardiology, Department of Internal Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Jen-Yuan Kuo
- Department of Medicine, MacKay Medical College, New Taipei City, Taiwan; Division of Cardiology, Department of Internal Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Cheng-I Lin
- Institute of Physiology, National Defense Medical Center, Taipei, Taiwan; Department of Biophysics, National Defense Medical Center, Taipei, Taiwan
| | - Yao-Chang Chen
- Biomedical Engineering, National Defense Medical Center, Taipei, Taiwan
| | - Shing-Jong Lin
- Institute of Clinical Medicine, and, Cardiovascular Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Hung-I Yeh
- Department of Medicine, MacKay Medical College, New Taipei City, Taiwan; Division of Cardiology, Department of Internal Medicine, National Yang-Ming University, Taipei, Taiwan.
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Bébarová M, Horáková Z, Kula R. Addictive drugs, arrhythmias, and cardiac inward rectifiers. Europace 2017; 19:346-355. [PMID: 27302393 DOI: 10.1093/europace/euw071] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 02/20/2016] [Indexed: 12/30/2022] Open
Abstract
In many addictive drugs including alcohol and nicotine, proarrhythmic effects were reported. This review provides an overview of the current knowledge in this field (with a focus on the inward rectifier potassium currents) to promote the lacking data and appeal for their completion, thus, to improve understanding of the proarrhythmic potential of addictive drugs.
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15
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Hirano-Iwata A, Ishinari Y, Yoshida M, Araki S, Tadaki D, Miyata R, Ishibashi K, Yamamoto H, Kimura Y, Niwano M. Reconstitution of Human Ion Channels into Solvent-free Lipid Bilayers Enhanced by Centrifugal Forces. Biophys J 2017; 110:2207-15. [PMID: 27224486 DOI: 10.1016/j.bpj.2016.04.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 04/11/2016] [Accepted: 04/11/2016] [Indexed: 12/26/2022] Open
Abstract
Artificially formed bilayer lipid membranes (BLMs) provide well-defined systems for functional analyses of various membrane proteins, including ion channels. However, difficulties associated with the integration of membrane proteins into BLMs limit the experimental efficiency and usefulness of such BLM reconstitution systems. Here, we report on the use of centrifugation to more efficiently reconstitute human ion channels in solvent-free BLMs. The method improves the probability of membrane fusion. Membrane vesicles containing the human ether-a-go-go-related gene (hERG) channel, the human cardiac sodium channel (Nav1.5), and the human GABAA receptor (GABAAR) channel were formed, and the functional reconstitution of the channels into BLMs via vesicle fusion was investigated. Ion channel currents were recorded in 67% of the BLMs that were centrifuged with membrane vesicles under appropriate centrifugal conditions (14-55 × g). The characteristic channel properties were retained for hERG, Nav1.5, and GABAAR channels after centrifugal incorporation into the BLMs. A comparison of the centrifugal force with reported values for the fusion force revealed that a centrifugal enhancement in vesicle fusion was attained, not by accelerating the fusion process but by accelerating the delivery of membrane vesicles to the surface of the BLMs, which led to an increase in the number of membrane vesicles that were available for fusion. Our method for enhancing the probability of vesicle fusion promises to dramatically increase the experimental efficiency of BLM reconstitution systems, leading to the realization of a BLM-based, high-throughput platform for functional assays of various membrane proteins.
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Affiliation(s)
- Ayumi Hirano-Iwata
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan.
| | - Yutaka Ishinari
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan
| | - Miyu Yoshida
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan
| | - Shun Araki
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan
| | - Daisuke Tadaki
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan
| | - Ryusuke Miyata
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan
| | | | - Hideaki Yamamoto
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Aoba, Sendai, Japan
| | - Yasuo Kimura
- Department of Electric and Electronic Engineering, School of Engineering, Tokyo University of Technology, Hachioji, Tokyo, Japan
| | - Michio Niwano
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan; Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Aoba, Sendai, Japan
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16
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Abstract
Alcohol intoxication is a potentially under-recognised precipitant of Brugada syndrome. Higher pre-cordial electrocardiogram lead placement increases sensitivity of detecting the Brugada pattern.
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Affiliation(s)
- Andrew Achaiah
- Cardiology Department, Queen Alexandra Hospital, Portsmouth, Hampshire PO63LY, UK
| | - Neil Andrews
- Cardiology Department, Queen Alexandra Hospital, Portsmouth, Hampshire PO63LY, UK
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17
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Insight into specific pro-arrhythmic triggers in Brugada and early repolarization syndromes: results of long-term follow-up. Heart Vessels 2016; 31:2035-2044. [PMID: 26968993 DOI: 10.1007/s00380-016-0828-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 02/26/2016] [Indexed: 02/03/2023]
Abstract
The pro-arrhythmic triggers in Brugada and early repolarization syndromes (BrS, ERS) have not been analyzed systematically except for case reports. We clinically investigated the circumstances which precede/predispose to arrhythmic events in these syndromes during long-term follow-up. A detailed history from the patients/witnesses was taken to investigate the antecedent events in the last few hours that preceded syncope/ventricular fibrillation (VF); medical records, ECG and blood test from the emergency room (ER) were reviewed. 19 patients that fulfilled the investigation criteria were followed up for 71 ± 49 months (34-190 months). Prior to the event (syncope/VF), the patients were partaking different activities in the following decreasing order; drinking alcoholic beverage, having meal, and getting up from sleep, exercise. 3 patients reported mental/physical stress prior to the event and 2 patients developed VF several days after starting oral steroid for treatment of bronchial asthma. In the ER, elevated J-wave amplitude (0.27 ± 0.15 mV) was found with 58 % of the patients having hypokalemia. After electrolyte correction and cessation of steroids, the following day plasma K+ (4.2 ± 0.3 mEq/L, P < 0.001) was significantly increased and J-wave amplitude (0.13 ± 0.1 mV, P < 0.001) was remarkably reduced. Three patients were kept on oral spironolactone/potassium supplements. During follow-up for 71 ± 49 (34-190) months, among 4 patients with VF recurrence, one patient developed VF after taking oral steroid. In ERS and BrS, hypokalemia and corticosteroid therapy add substantial pro-arrhythmic effects, but potentially treatable. Stopping steroid therapy and avoiding hypokalemia had excellent long-term outcome.
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18
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Xie C, Liu HW, Pan N, Ding JP, Yao J. The residue I257 at S4-S5 linker in KCNQ1 determines KCNQ1/KCNE1 channel sensitivity to 1-alkanols. Acta Pharmacol Sin 2016; 37:124-33. [PMID: 26725740 DOI: 10.1038/aps.2015.133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 11/10/2015] [Indexed: 01/03/2023] Open
Abstract
AIM KCNQ1 and KCNE1 form a complex in human ventricular cardiomyocytes, which are important in maintaining a normal heart rhythm. In the present study we investigated the effects of a homologous series of 1-alkanols on KCNQ1/KCNE1 channels expressed in Xenopus oocytes. METHODS ECG recording was made in rats injected with ethanol-containing solution (0.3 mL, ip). Human KCNQ1 channel and its auxiliary subunit KCNE1 were heterologously coexpressed in Xenopus oocytes, which were superfused with ND96 solution; 1-alkanols (ethanol, 1-butanol and 1-hexanol) were delivered through a gravity-driven perfusion device. The slow-delayed rectifier potassium currents IKs (KCNQ1/KCNE1 currents) were recorded using a two-electrode voltage clamp method. Site-directed mutations (I257A) were made in KCNQ1. RESULTS In ECG recordings, a low concentration of ethanol (3%, v/v) slightly increased the heart rate of rats, whereas the higher concentrations of ethanol (10%, 50%, v/v) markedly reduced it. In oocytes coexpressing KCNQ1/KCNE1 channels, ethanol, 1-butanol and 1-hexanol dose-dependently inhibited IKs currents with IC50 values of 80, 11 and 2.7 mmol/L, respectively. Furthermore, the 1-alkanols blocked the KCNQ1 channel in both open and closed states, and a four-state model could adequately explain the effects of 1-alkanols on the closed-state channel block. Moreover, the mutation of I257A at the intracellular loop between S4 and S5 in KCNQ1 greatly decreased the sensitivity to 1-alkanols; and the IC50 values of ethanol, 1-butanol and 1-hexanol were increased to 634, 414 and 7.4 mmol/L, respectively. The mutation also caused the ablation of closed-state channel block. CONCLUSION These findings provide new insight into the intricate mechanisms of the blocking effects of ethanol on the KCNQ1 channel.
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19
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Acute effects of ethanol on action potential and intracellular Ca(2+) transient in cardiac ventricular cells: a simulation study. Med Biol Eng Comput 2015; 54:753-62. [PMID: 26280513 DOI: 10.1007/s11517-015-1366-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 08/03/2015] [Indexed: 01/08/2023]
Abstract
Alcohol consumption may result in electrocardiographic changes and arrhythmias, at least partly due to effects of ethanol on cardiac ionic currents. Contractility and intracellular Ca(2+) dynamics seem to be altered as well. In this study, we integrated the available (mostly animal) experimental data into previously published models of the rat and human ventricular myocytes to assess the share of ionic current components in ethanol-induced changes in AP configuration and cytosolic Ca(2+) transient in ventricular cardiomyocytes. The rat model reproduced well the experimentally observed changes in AP duration (APD) under ethanol (slight prolongation at 0.8 mM and shortening at ≥8 mM). These changes were almost exclusively caused by the ethanol-induced alterations of I K1. The cytosolic Ca(2+) transient decreased gradually with the increasing ethanol concentration as a result of the ethanol-induced inhibition of I Ca. In the human model, ethanol produced a dose-dependent APD lengthening, dominated by ethanol effect on I Kr, the key repolarising current in human ventricles. This effect might contribute to the clinically observed proarrhythmic effects of ethanol in predisposed individuals.
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20
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Forrest MD. Simulation of alcohol action upon a detailed Purkinje neuron model and a simpler surrogate model that runs >400 times faster. BMC Neurosci 2015; 16:27. [PMID: 25928094 PMCID: PMC4417229 DOI: 10.1186/s12868-015-0162-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Accepted: 04/10/2015] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND An approach to investigate brain function/dysfunction is to simulate neuron circuits on a computer. A problem, however, is that detailed neuron descriptions are computationally expensive and this handicaps the pursuit of realistic network investigations, where many neurons need to be simulated. RESULTS We confront this issue; we employ a novel reduction algorithm to produce a 2 compartment model of the cerebellar Purkinje neuron from a previously published, 1089 compartment model. It runs more than 400 times faster and retains the electrical behavior of the full model. So, it is more suitable for inclusion in large network models, where computational power is a limiting issue. We show the utility of this reduced model by demonstrating that it can replicate the full model's response to alcohol, which can in turn reproduce experimental recordings from Purkinje neurons following alcohol application. CONCLUSIONS We show that alcohol may modulate Purkinje neuron firing by an inhibition of their sodium-potassium pumps. We suggest that this action, upon cerebellar Purkinje neurons, is how alcohol ingestion can corrupt motor co-ordination. In this way, we relate events on the molecular scale to the level of behavior.
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Affiliation(s)
- Michael D Forrest
- Department of Computer Science, University of Warwick, Coventry, West Midlands, UK.
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21
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Turagam MK, Velagapudi P, Kocheril AG, Alpert MA. Commonly consumed beverages in daily life: do they cause atrial fibrillation? Clin Cardiol 2015; 38:317-22. [PMID: 25707748 DOI: 10.1002/clc.22385] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 12/09/2014] [Accepted: 12/19/2014] [Indexed: 01/02/2023] Open
Abstract
Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia in the United States and worldwide. Caffeine, alcohol, and, more recently, energy drinks are the most commonly consumed beverages in daily living, especially by young individuals. Several questions have been raised about the implications of caffeine, alcohol, and energy drinks in cardiovascular health, especially in triggering AF. This review focuses on the role of these commonly consumed beverages as a cause of AF, with special emphasis of potential mechanisms and studies addressing this issue.
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Affiliation(s)
- Mohit K Turagam
- Division of Cardiovascular Medicine, University of Missouri School of Medicine, Columbia, Missouri
| | - Poonam Velagapudi
- Division of Cardiovascular Medicine, University of Missouri School of Medicine, Columbia, Missouri
| | - Abraham G Kocheril
- Division of Cardiovascular Electrophysiology, University of Illinois College of Medicine, Urbana-Champaign, Illinois
| | - Martin A Alpert
- Division of Cardiovascular Medicine, University of Missouri School of Medicine, Columbia, Missouri
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22
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Herold KF, Sanford RL, Lee W, Schultz MF, Ingólfsson HI, Andersen OS, Hemmings HC. Volatile anesthetics inhibit sodium channels without altering bulk lipid bilayer properties. J Gen Physiol 2014; 144:545-60. [PMID: 25385786 PMCID: PMC4242807 DOI: 10.1085/jgp.201411172] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 10/08/2014] [Indexed: 01/05/2023] Open
Abstract
Although general anesthetics are clinically important and widely used, their molecular mechanisms of action remain poorly understood. Volatile anesthetics such as isoflurane (ISO) are thought to alter neuronal function by depressing excitatory and facilitating inhibitory neurotransmission through direct interactions with specific protein targets, including voltage-gated sodium channels (Na(v)). Many anesthetics alter lipid bilayer properties, suggesting that ion channel function might also be altered indirectly through effects on the lipid bilayer. We compared the effects of ISO and of a series of fluorobenzene (FB) model volatile anesthetics on Na(v) function and lipid bilayer properties. We examined the effects of these agents on Na(v) in neuronal cells using whole-cell electrophysiology, and on lipid bilayer properties using a gramicidin-based fluorescence assay, which is a functional assay for detecting changes in lipid bilayer properties sensed by a bilayer-spanning ion channel. At clinically relevant concentrations (defined by the minimum alveolar concentration), both the FBs and ISO produced prepulse-dependent inhibition of Na(v) and shifted the voltage dependence of inactivation toward more hyperpolarized potentials without affecting lipid bilayer properties, as sensed by gramicidin channels. Only at supra-anesthetic (toxic) concentrations did ISO alter lipid bilayer properties. These results suggest that clinically relevant concentrations of volatile anesthetics alter Na(v) function through direct interactions with the channel protein with little, if any, contribution from changes in bulk lipid bilayer properties. Our findings further suggest that changes in lipid bilayer properties are not involved in clinical anesthesia.
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Affiliation(s)
- Karl F Herold
- Department of Anesthesiology, Department of Physiology and Biophysics, and Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065
| | - R Lea Sanford
- Department of Anesthesiology, Department of Physiology and Biophysics, and Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065
| | - William Lee
- Department of Anesthesiology, Department of Physiology and Biophysics, and Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065
| | - Margaret F Schultz
- Department of Anesthesiology, Department of Physiology and Biophysics, and Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065
| | - Helgi I Ingólfsson
- Department of Anesthesiology, Department of Physiology and Biophysics, and Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065
| | - Olaf S Andersen
- Department of Anesthesiology, Department of Physiology and Biophysics, and Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065
| | - Hugh C Hemmings
- Department of Anesthesiology, Department of Physiology and Biophysics, and Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065 Department of Anesthesiology, Department of Physiology and Biophysics, and Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065
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23
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Tonelo D, Providência R, Gonçalves L. Holiday heart syndrome revisited after 34 years. Arq Bras Cardiol 2013; 101:183-9. [PMID: 24030078 PMCID: PMC3998158 DOI: 10.5935/abc.20130153] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2012] [Revised: 10/13/2012] [Accepted: 01/30/2013] [Indexed: 11/20/2022] Open
Abstract
The cardiovascular effects of alcohol are well known. However, most research has focused on the beneficial effects (the "French paradox") of moderate consumption or the harmful consequences, such as dilated cardiomyopathy, associated with heavy consumption over an extended period. An association between the ingestion of acute alcohol and onset of cardiac arrhythmias was first reported in the early 70's. In 1978, Philip Ettinger described "Holiday heart syndrome" (HHS) for the first time, as the occurrence, in healthy people without heart disease known to cause arrhythmia, of an acute cardiac rhythm disturbance, most frequently atrial fibrillation, after binge drinking. The name is derived from the fact that episodes were initially observed more frequently after weekends or public holidays. Since the original description of HHS, 34 years have passed and new research in this field has increased the volume of knowledge related to this syndrome. Throughout this paper the authors will comprehensively review most of the available data concerning HHS and highlight the questions that remain unresolved.
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Affiliation(s)
- David Tonelo
- Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Rui Providência
- Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- Coimbras Hospital Centre and University, Coimbra - Portugal
| | - Lino Gonçalves
- Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- Coimbras Hospital Centre and University, Coimbra - Portugal
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24
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Glatter KA, Myers R, Chiamvimonvat N. Recommendations regarding dietary intake and caffeine and alcohol consumption in patients with cardiac arrhythmias: what do you tell your patients to do or not to do? CURRENT TREATMENT OPTIONS IN CARDIOVASCULAR MEDICINE 2012; 14:529-35. [PMID: 22865244 DOI: 10.1007/s11936-012-0193-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
OPINION STATEMENT The etiology of arrhythmias including atrial fibrillation is multifactorial. Most arrhythmias are associated with comorbid illnesses like hypertension, diabetes, thyroid disease, or advanced age. Although it is tempting to blame a stimulant like caffeine as a trigger for arrhythmias, the literature does not support this idea. There is no real benefit to having patients with arrhythmias limit their caffeine intake. Caffeine is a vasoactive substance that also may promote the release of norepinephrine and epinephrine. However, acute ingestion of caffeine (as coffee or tea) does not cause atrial fibrillation. Even patients suffering a myocardial infarction do not have an increased incidence of ventricular or other arrhythmias after ingesting several cups of coffee. Large epidemiologic studies have also failed to find a connection between the amount of coffee/caffeine used and the development of arrhythmias. As such, it does not make sense to suggest that patients with palpitations, paroxysmal atrial fibrillation, or supraventricular tachycardia, abstain from caffeine use. Energy drinks are a new phenomenon on the beverage market, with 30-50 % of young adults and teens using them regularly. Energy drinks are loaded with caffeine, sugar, and other chemicals that can stimulate the cardiac system. There is an increasing body of mainly anecdotal case reports describing arrhythmias or even sudden death triggered by exercise plus using energy drinks. Clearly, there must be more study in this area, but it is wise to either limit or avoid their use in patients with arrhythmias. Moderate to heavy alcohol use seems to be associated with the development of atrial fibrillation. The term "holiday heart" was coined back in 1978, to describe patients who had atrial fibrillation following binge alcohol use. Thus, it is reasonable to recommend to patients with arrhythmias that they limit their alcohol use, although unfortunately this treatment will likely not completely resolve their arrhythmia.
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Affiliation(s)
- Kathryn A Glatter
- Woodland Clinic Medical Group, 632 West Gibson Road, Woodland, CA, 95695, USA,
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25
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Rosenberg MA, Mukamal KJ. The Estimated Risk of Atrial Fibrillation Related to Alcohol Consumption. J Atr Fibrillation 2012; 5:424. [PMID: 28496744 DOI: 10.4022/jafib.424] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 12/23/2011] [Accepted: 12/25/2011] [Indexed: 01/19/2023]
Abstract
The risk of acute heavy alcohol intake on the development of atrial fibrillation (AF), aka ?holiday heart syndrome?, has been well-described. However, whether chronic alcohol intake is also associated with increased risk of AF, or might even be protective as has been observed with other cardiac conditions, is more uncertain. A number of studies, from basic science to large cohort studies have been performed to analyze the association between alcohol and AF. Basic-level studies have found that alcohol causes changes in tissue electrophysiology, ion channels, and circulating hormones, which might promote development and maintenance of AF. Clinical studies have generally shown groups with the highest regular intake of alcohol to be at increased risk, with no association with more moderate use. However, these studies have not always accounted for other AF risk factors, been inconsistent in the assessment and validation of the quantity of alcohol consumed across populations, and been unable to completely separate drinking patterns from overall health of participants. As a result, solid conclusions about a threshold level for ?safe? chronic alcohol intake cannot be made with regard to AF risk, but it appears to be safe within currently recommended limits of 1 drink daily for women and 2 for men. In this review, we discuss these findings, limitations, and conclusions.
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Affiliation(s)
- Michael A Rosenberg
- Cardiovascular Institute, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Kenneth J Mukamal
- Division of General Medicine and Primary Care, Beth Israel Deaconess Medical Center, Boston, MA, USA
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26
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Nikolić S, Zivković V. A healed bony puzzle: an old gunshot wound to the head. Forensic Sci Med Pathol 2012; 9:112-6. [PMID: 22392017 DOI: 10.1007/s12024-012-9324-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/08/2012] [Indexed: 11/24/2022]
Affiliation(s)
- Slobodan Nikolić
- Institute of Forensic Medicine, University of Belgrade - School of Medicine, 31a Deligradska str., 11000, Belgrade, Serbia.
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27
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Botta P, Simões de Souza FM, Sangrey T, De Schutter E, Valenzuela CF. Excitation of rat cerebellar Golgi cells by ethanol: further characterization of the mechanism. Alcohol Clin Exp Res 2011; 36:616-24. [PMID: 22004123 DOI: 10.1111/j.1530-0277.2011.01658.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
BACKGROUND Studies with rodents suggest that acute ethanol exposure impairs information flow through the cerebellar cortex, in part, by increasing GABAergic input to granule cells. Experiments suggest that an increase in the excitability of specialized GABAergic interneurons that regulate granule cell activity (i.e., Golgi cells [GoCs]) contributes to this effect. In GoCs, ethanol increases spontaneous action potential firing frequency, decreases the afterhyperpolarization amplitude, and depolarizes the membrane potential. Studies suggest that these effects could be mediated by inhibition of the Na(+)/K(+) ATPase. The purpose of this study was to characterize the potential role of other GoC conductances in the mechanism of action of ethanol. METHODS Computer modeling techniques and patch-clamp electrophysiological recordings with acute slices from rat cerebella were used for these studies. RESULTS Computer modeling suggested that modulation of subthreshold Na(+) channels, hyperpolarization-activated currents, and several K(+) conductances could explain some but not all actions of ethanol on GoCs. Electrophysiological studies did not find evidence consistent with a contribution of these conductances. Quinidine, a nonselective blocker of several types of channels (including several K(+) channels) that also antagonizes the Na(+)/K(+) ATPase, reduced the effect of ethanol on GoC firing. CONCLUSIONS These findings further support that ethanol increases GoC excitability via modulation of the Na(+)/K(+) ATPase and suggest that a quinidine-sensitive K(+) channel may also play a role in the mechanism of action of ethanol.
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Affiliation(s)
- Paolo Botta
- Department of Neurosciences, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, USA
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28
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van Cleef ANH, Schuurman MJ, Busari JO. Third-degree atrioventricular block in an adolescent following acute alcohol intoxication. BMJ Case Rep 2011; 2011:bcr.07.2011.4547. [PMID: 22679160 DOI: 10.1136/bcr.07.2011.4547] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Alcohol abuse is a major problem among adolescents, and has both acute, potentially lethal, and long-term harmful effects. The authors describe an adolescent who was in a subcomatose condition after binge drinking. His serum alcohol concentration was 3.7 g/l. The next morning, before transfer to the paediatric ward, he developed a third-degree atrioventricular (AV) block without cardiac output while his infusion needle was removed. This recovered spontaneously after a precordial thump. Retrospectively, electrocardiography showed an increasing PR prolongation (200-300 ms) before the removal of the infusion needle. ECG recordings several hours later showed a first-degree AV block, which was no longer seen during follow-up, 1 month later. The authors conclude that acute alcohol poisoning has the potential to prolong the PR interval in young, healthy adolescents without pre-existing first-degree AV block and provoke a third-degree AV block after vagal stimulation. It is yet another potential danger of acute alcohol intoxication in this age group.
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Affiliation(s)
- Anne N H van Cleef
- Department of Pediatrics, Atrium Medical Centre, Heerlen, The Netherlands
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Bébarová M, Matejovič P, Pásek M, Ohlídalová D, Jansová D, Simurdová M, Simurda J. Effect of ethanol on action potential and ionic membrane currents in rat ventricular myocytes. Acta Physiol (Oxf) 2010; 200:301-14. [PMID: 20618172 DOI: 10.1111/j.1748-1716.2010.02162.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIM Even though alcohol intoxication is often linked to arrhythmias, data describing ethanol effect on cardiac ionic channels are rare. In addition, ethanol is used as a solvent of hydrophobic compounds in experimental studies. We investigated changes of the action potential (AP) configuration and main ionic membrane currents in rat cardiomyocytes under 20-1500 m(M) ethanol. METHODS Experiments were performed on enzymatically isolated rat right ventricular myocytes using the whole cell patch-clamp technique at room temperature. RESULTS Ethanol reversibly decelerated the upstroke velocity and decreased AP amplitude and duration at 0.2 and 3 Hz. The fast sodium current I(Na) , l-type calcium current I(Ca) and transient outward potassium current I(to) were reversibly inhibited in a concentration-dependent manner (50% inhibition at 446 ± 12, 553 ± 49 and 1954 ± 234 m(M), respectively, with corresponding Hill coefficients 3.1 ± 0.3, 1.1 ± 0.2 and 0.9 ± 0.1). Suppression of I(Na) and I(Ca) magnitude was slightly voltage dependent. The effect on I(Ca) and I(to) was manifested mainly as an acceleration of their apparent inactivations with a decreased slow and fast time constant respectively. As a consequence of marked differences in n(H) , sensitivity of the currents to ethanol at 10% inhibition decreases in the following order: I(Ca) (75 mm, 3.5‰), I(to) (170 m(M), 7.8‰) and I(Na) (220 m(M), 10.1‰). CONCLUSION Our results suggest a slight inhibition of all the currents at ethanol concentrations relevant to deep alcohol intoxication. The concentration dependence measured over a wide range may serve as a guideline when using ethanol as a solvent.
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Affiliation(s)
- M Bébarová
- Department of Physiology, Masaryk University, Brno - Bohunice, Czech Republic.
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Chiuve SE, Rimm EB, Mukamal KJ, Rexrode KM, Stampfer MJ, Manson JE, Albert CM. Light-to-moderate alcohol consumption and risk of sudden cardiac death in women. Heart Rhythm 2010; 7:1374-80. [PMID: 20638933 PMCID: PMC2946479 DOI: 10.1016/j.hrthm.2010.05.035] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Accepted: 05/24/2010] [Indexed: 11/26/2022]
Abstract
BACKGROUND Moderate alcohol intake is associated with lower risk of coronary heart disease (CHD), but the association with sudden cardiac death (SCD) is less clear. In men, heavy alcohol consumption may increase risk of SCD, whereas light-to-moderate alcohol intake may lower risk. There are no parallel data among women. OBJECTIVE The purpose of this study was to assess the association between alcohol intake and risk of SCD among women and to investigate how this risk compared to other forms of CHD. METHODS We conducted a prospective cohort study among 85,067 women from the Nurses' Health Study who were free of chronic disease at baseline. Alcohol intake was assessed every 4 years through questionnaires. Primary endpoints included SCD, fatal CHD, and nonfatal myocardial infarction. RESULTS We found a U-shaped association between alcohol intake and risk of SCD, with the lowest risk among women who drank 5.0-14.9 g/day of alcohol (P for quadratic trend = 0.02). Compared to abstainers, the multivariate relative risk (95% confidence interval) for SCD was 0.79 (0.55-1.14) for former drinkers, 0.77 (0.57-1.06) for 0.1-4.9 g/day, 0.64 (0.43-0.95) for 5.0-14.9 g/day, 0.68 (0.38-1.23) for 15.0-29.9 g/day, and 1.15 (0.70-1.87) for ≥30.0 g/day. In contrast, the relationship of alcohol intake and nonfatal and fatal CHD was more linear (P for linear trend <.001). CONCLUSION In this cohort of women, the relationship between light-to-moderate alcohol intake and SCD is U-shaped, with a nadir at 5.0-14.9 g/day. Low levels of alcohol intake do not raise the risk of SCD and may lower risk in women.
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Affiliation(s)
- Stephanie E Chiuve
- Center for Arrhythmia Prevention, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA.
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Agrawal S, Payal YS, Burathoki S, Asthana V, Rizvi A, Sharma JP. Case study: Systemic complications following absolute alcohol embolisation of scalp arteriovenous malformation. SOUTHERN AFRICAN JOURNAL OF ANAESTHESIA AND ANALGESIA 2010. [DOI: 10.1080/22201173.2010.10872669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Cameli M, Ballo P, Garzia A, Lisi M, Palmerini E, Spinelli T, Bocelli A, Mondillo S. Acute Effects of Low Doses of Red Wine on Cardiac Conduction and Repolarization in Young Healthy Subjects. Alcohol Clin Exp Res 2009; 33:2141-6. [DOI: 10.1111/j.1530-0277.2009.01054.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Aasebø W. ECG-voltage in alcoholics and non-alcoholics with acute alcohol intoxication. J Forensic Leg Med 2009; 16:381-4. [DOI: 10.1016/j.jflm.2009.01.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2008] [Revised: 08/26/2008] [Accepted: 01/15/2009] [Indexed: 10/21/2022]
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Laszlo R, Eick C, Schwiebert M, Schreiner B, Weig HJ, Weretka S, Bosch RF, Schreieck J. Alcohol-Induced Electrical Remodeling: Effects of Sustained Short-Term Ethanol Infusion on Ion Currents in Rabbit Atrium. Alcohol Clin Exp Res 2009; 33:1697-703. [DOI: 10.1111/j.1530-0277.2009.01006.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Treistman SN, Martin GE. BK Channels: mediators and models for alcohol tolerance. Trends Neurosci 2009; 32:629-37. [PMID: 19781792 DOI: 10.1016/j.tins.2009.08.001] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 07/30/2009] [Accepted: 08/05/2009] [Indexed: 12/16/2022]
Abstract
Enhanced acute tolerance predicts alcohol abuse. We describe work on the role of the calcium- and voltage-gated BK channel in alcohol tolerance, highlighting the lipid environment, BK protein isoform selection and auxiliary BK channel proteins. We show how ethanol, which had the reputation of a nonspecific membrane perturbant, is now being examined at realistic concentrations with cutting-edge techniques, providing novel molecular targets for therapeutic approaches to alcoholism. Addictive disorders impact our emotional, physical and financial status, and burden our healthcare system. Although alcohol is the focus of this review, it is highly probable, given the common neural and biochemical pathways used by drugs of abuse, that the findings described here will also apply to other drugs.
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Affiliation(s)
- Steven N Treistman
- Institute of Neurobiology, University of Puerto Rico Medical Sciences Campus, San Juan 00901, Puerto Rico.
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Hayashi T, Mitani H, Goto K, Ishimura R, Tao S, Ito S, Masuda J, Fujimoto H, Fujimoto Y, Ishiwata S, Yamaguchi T, Ohno M. Alcohol-induced Ventricular Fibrillation in Brugada Syndrome. J Arrhythm 2009. [DOI: 10.1016/s1880-4276(09)80031-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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Wallner M, Olsen RW. Physiology and pharmacology of alcohol: the imidazobenzodiazepine alcohol antagonist site on subtypes of GABAA receptors as an opportunity for drug development? Br J Pharmacol 2008; 154:288-98. [PMID: 18278063 DOI: 10.1038/bjp.2008.32] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Alcohol (ethanol, EtOH) has pleiotropic actions and induces a number of acute and long-term effects due to direct actions on alcohol targets, and effects of alcohol metabolites and metabolism. Many detrimental health consequences are due to EtOH metabolism and metabolites, in particular acetaldehyde, whose high reactivity leads to nonspecific chemical modifications of proteins and nucleic acids. Like acetaldehyde, alcohol has been widely considered a nonspecific drug, despite rather persuasive evidence implicating inhibitory GABA(A) receptors (GABA(A)Rs) in acute alcohol actions, for example, a GABA(A)R ligand, the imidazobenzodiazepine Ro15-4513 antagonizes many low-to-moderate dose alcohol actions in mammals. It was therefore rather surprising that abundant types of synaptic GABA(A)Rs are generally not responsive to relevant low concentrations of EtOH. In contrast, delta-subunit-containing GABA(A)Rs and extrasynaptic tonic GABA currents mediated by these receptors are sensitive to alcohol concentrations that are reached in blood and tissues during low-to-moderate alcohol consumption. We recently showed that low-dose alcohol enhancement on highly alcohol-sensitive GABA(A)R subtypes is antagonized by Ro15-4513 in an apparently competitive manner, providing a molecular explanation for behavioural Ro15-4513 alcohol antagonism. The identification of a Ro15-4513/EtOH binding site on unique GABA(A)R subtypes opens the possibility to characterize this alcohol site(s) and screen for compounds that modulate the function of EtOH/Ro15-4513-sensitive GABA(A)Rs. The utility of such drugs might range from novel alcohol antagonists that might be useful in the emergency room, to drugs for the treatment of alcoholism, as well as alcohol-mimetic drugs to harness acute positive effects of alcohol.
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Affiliation(s)
- M Wallner
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, CA 90095-1735, USA.
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Morris CE, Juranka PF. Nav channel mechanosensitivity: activation and inactivation accelerate reversibly with stretch. Biophys J 2007; 93:822-33. [PMID: 17496023 PMCID: PMC1913161 DOI: 10.1529/biophysj.106.101246] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Voltage-gated sodium channels (Nav) are modulated by many bilayer mechanical amphiphiles, but whether, like other voltage-gated channels (Kv, HCN, Cav), they respond to physical bilayer deformations is unknown. We expressed human heart Nav1.5 pore alpha-subunit in oocytes (where, unlike alphaNav1.4, alphaNav1.5 exhibits normal kinetics) and measured small macroscopic currents in cell-attached patches. Pipette pressure was used to reversibly stretch the membrane for comparison of I(Na)(t) before, during, and after stretch. At all voltages, and in a dose-dependent fashion, stretch accelerated the I(Na)(t) time course. The sign of membrane curvature was not relevant. Typical stretch stimuli reversibly accelerated both activation and inactivation by approximately 1.4-fold; normalization of peak I(Na)(t) followed by temporal scaling ( approximately 1.30- to 1.85-fold) resulted in full overlap of the stretch/no-stretch traces. Evidently the rate-limiting outward voltage sensor motion in the Nav1.5 activation path (as in Kv1) accelerated with stretch. Stretch-accelerated inactivation occurred even with activation saturated, so an independently stretch-modulated inactivation transition is also a possibility. Since Nav1.5 channel-stretch modulation was both reliable and reversible, and required stretch stimuli no more intense than what typically activates putative mechanotransducer channels (e.g., stretch-activated TRPC1-based currents), Nav channels join the ranks of putative mechanotransducers. It is noteworthy that at voltages near the activation threshold, moderate stretch increased the peak I(Na) amplitude approximately 1.5-fold. It will be important to determine whether stretch-modulated Nav current contributes to cardiac arrhythmias, to mechanosensory responses in interstitial cells of Cajal, to touch receptor responses, and to neuropathic (i.e., hypermechanosensitive) and/or normal pain reception.
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Affiliation(s)
- Catherine E Morris
- Neuroscience, Ottawa Health Research Institute, Ottawa, Ontario, Canada.
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