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Albrecht PA, Fernandez-Hubeid LE, Deza-Ponzio R, Virgolini MB. The intertwining between lead and ethanol in the model organism Caenorhabditis elegans. FRONTIERS IN TOXICOLOGY 2022; 4:991787. [PMID: 36204698 PMCID: PMC9531147 DOI: 10.3389/ftox.2022.991787] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 08/18/2022] [Indexed: 11/16/2022] Open
Abstract
Caenorhabditis elegans (C. elegans) is a model organism widely used to evaluate the mechanistic aspects of toxicants with the potential to predict responses comparable to those of mammals. We report here the consequences of developmental lead (Pb) exposure on behavioral responses to ethanol (EtOH) in C. elegans. In addition, we present data on morphological alterations in the dopamine (DA) synapse and DA-dependent behaviors aimed to dissect the neurobiological mechanisms that underlie the relationship between these neurotoxicants. Finally, the escalation to superior animals that parallels the observed effects in both experimental models with references to EtOH metabolism and oxidative stress is also discussed. Overall, the literature revised here underpins the usefulness of C. elegans to evidence behavioral responses to a combination of neurotoxicants in mechanistic-orientated studies.
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Affiliation(s)
- P A Albrecht
- Departamento de Farmacología Otto Orsingher, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Instituto de Farmacología Experimental de Córdoba-Consejo Nacional de Investigaciones Científicas y Técnicas (IFEC-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - L E Fernandez-Hubeid
- Departamento de Farmacología Otto Orsingher, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Instituto de Farmacología Experimental de Córdoba-Consejo Nacional de Investigaciones Científicas y Técnicas (IFEC-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - R Deza-Ponzio
- Departamento de Farmacología Otto Orsingher, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Instituto de Farmacología Experimental de Córdoba-Consejo Nacional de Investigaciones Científicas y Técnicas (IFEC-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - M B Virgolini
- Departamento de Farmacología Otto Orsingher, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Instituto de Farmacología Experimental de Córdoba-Consejo Nacional de Investigaciones Científicas y Técnicas (IFEC-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
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Wu ZQ, Li K, Ma JK, Li ZJ. Effects of ethanol intake on anti-oxidant responses and the lifespan of Caenorhabditis elegans. CYTA - JOURNAL OF FOOD 2019. [DOI: 10.1080/19476337.2018.1564794] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Zhong-Qin Wu
- Hunan Province Key Laboratory of Food Science and Biotechnology, College of Food Science and Technology, Hunan Agricultural University, Changsha, PR China
| | - Ke Li
- Hunan Province Key Laboratory of Food Science and Biotechnology, College of Food Science and Technology, Hunan Agricultural University, Changsha, PR China
| | - Jin-Kui Ma
- School of Food & Pharmaceutical Engineering, Zhaoqing University, Zhaoqing, PR China
| | - Zong-Jun Li
- Hunan Province Key Laboratory of Food Science and Biotechnology, College of Food Science and Technology, Hunan Agricultural University, Changsha, PR China
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Shah A, Zuo W, Kang S, Li J, Fu R, Zhang H, Bekker A, Ye JH. The lateral habenula and alcohol: Role of glutamate and M-type potassium channels. Pharmacol Biochem Behav 2017. [PMID: 28624587 DOI: 10.1016/j.pbb.2017.06.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Alcohol use disorder (AUD) or alcoholism is a chronic relapsing disorder. Our knowledge of alcoholism hinges on our understanding of its effects on the brain. This review will center on the effects of alcohol in the lateral habenula (LHb), an epithalamic structure that connects the forebrain with the midbrain and encodes aversive signaling. Like many addictive drugs, alcohol has both rewarding and aversive properties. While alcohol's euphoric property is believed to be important for the initiation of drinking, increasing evidence suggests that alcohol's negative affect plays a critical role in excessive drinking and alcohol dependence. During withdrawal and abstinence, alcoholics often experience anxiety and depressions, both of which have been implicated in relapse drinking. This review focuses on the recent accumulation of knowledge about the effects of acute and chronic alcohol exposure on the activity of and synaptic transmissions on LHb neurons, as well as the effects of manipulation of LHb function on alcohol consumption and related behaviors. Recent evidence highlights a critical role for the LHb in AUD and related psychiatric ailments. Multidisciplinary work in animals collectively suggests that LHb function and activity, including M-type potassium channels and glutamatergic transmission are altered by acute and repeated chronic alcohol exposure. We will also discuss how functional, pharmacological, and chemogenetic manipulation of the LHb affects ethanol drinking and psychiatric disorders occurring in animals withdrawn from chronic alcohol exposure. Conceivable mechanisms behind these effects and their potential as targets for therapies will also be discussed.
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Affiliation(s)
- Avi Shah
- Department of Anesthesiology, Rutgers, The State University of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA; Department of Pharmacology, Physiology and Neuroscience, Rutgers, The State University of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA
| | - Wanhong Zuo
- Department of Anesthesiology, Rutgers, The State University of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA; Department of Pharmacology, Physiology and Neuroscience, Rutgers, The State University of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA
| | - Seungwoo Kang
- Department of Anesthesiology, Rutgers, The State University of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA; Department of Pharmacology, Physiology and Neuroscience, Rutgers, The State University of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA
| | - Jing Li
- Department of Anesthesiology, Rutgers, The State University of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA; Department of Pharmacology, Physiology and Neuroscience, Rutgers, The State University of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA
| | - Rao Fu
- Department of Anesthesiology, Rutgers, The State University of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA; Department of Pharmacology, Physiology and Neuroscience, Rutgers, The State University of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA
| | - Haifeng Zhang
- Department of Anesthesiology, Rutgers, The State University of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA; Department of Pharmacology, Physiology and Neuroscience, Rutgers, The State University of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA
| | - Alex Bekker
- Department of Anesthesiology, Rutgers, The State University of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA; Department of Pharmacology, Physiology and Neuroscience, Rutgers, The State University of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA
| | - Jiang-Hong Ye
- Department of Anesthesiology, Rutgers, The State University of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA; Department of Pharmacology, Physiology and Neuroscience, Rutgers, The State University of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA.
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Insulin signaling genes modulate nicotine-induced behavioral responses in Caenorhabditis elegans. Behav Pharmacol 2016; 27:44-9. [PMID: 26317299 DOI: 10.1097/fbp.0000000000000186] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Insulin signaling has been suggested to modulate nicotine dependence, but the underlying genetic evidence has been lacking. Here, we used the nematode, Caenorhabditis elegans, to investigate whether genetic alterations in the insulin signaling pathway affect behavioral responses to nicotine. For this, we challenged drug-naive C. elegans with an acute dose of nicotine (100 μmol/l) while recording changes in their locomotion speed. Although nicotine treatment stimulated locomotion speed in wild-type C. elegans, the same treatment reduced locomotion speed in mutants defective in insulin signaling. This phenotype could be suppressed by mutations in daf-16, a gene encoding a FOXO transcription factor that acts downstream of insulin signaling. Our data suggest that insulin signaling genes, daf-2, age-1, pdk-1, akt-1, and akt-2, modulate behavioral responses to nicotine in C. elegans, indicating a genetic link between nicotine behavior and insulin signaling.
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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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Li X, Ghezzi A, Krishnan HR, Pohl JB, Bohm AY, Atkinson NS. A histone modification identifies a DNA element controlling slo BK channel gene expression in muscle. J Neurogenet 2015; 29:124-34. [PMID: 25967280 DOI: 10.3109/01677063.2015.1050097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The slo gene encodes the BK-type Ca(2+)-activated K(+) channels. In Drosophila, expression of slo is induced by organic solvent sedation (benzyl alcohol and ethanol), and this increase in neural slo expression contributes to the production of functional behavioral tolerance (inducible resistance) to these drugs. Within the slo promoter region, we observed that benzyl alcohol sedation produces a localized spike of histone acetylation over a 65-nucleotide (65-n) conserved DNA element called 55b. Changes in histone acetylation are commonly the consequence of transcription factor activity, and previously, a localized histone acetylation spike was used to successfully map a DNA element involved in benzyl alcohol-induced slo expression. To determine whether the 55b element was also involved in benzyl alcohol-induced neural expression of slo, we deleted it from the endogenous slo gene by homologous recombination. Flies lacking the 55b element were normal with respect to basal and benzyl alcohol-induced neural slo expression, the capacity to acquire and maintain functional tolerance, their threshold for electrically-induced seizures, and most slo-related behaviors. Removal of the 55b element did however increase the level of basal expression from the muscle/tracheal cell-specific slo core promoter and produced a slight increase in overall locomotor activity. We conclude that the 55b element is involved in control of slo expression from the muscle and tracheal-cell promoter but is not involved in the production of functional benzyl alcohol tolerance.
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Affiliation(s)
- Xiaolei Li
- a School of Biological Sciences, Nanyang Technological University , Singapore
| | - Alfredo Ghezzi
- b Department of Neuroscience and The Waggoner Center for Alcohol and Addiction Research , The University of Texas at Austin , Austin, Texas , USA
| | - Harish R Krishnan
- c Department of Psychiatry , University of Illinois at Chicago and Jesse Brown VA Medical Center , Chicago , IL , USA
| | - Jascha B Pohl
- b Department of Neuroscience and The Waggoner Center for Alcohol and Addiction Research , The University of Texas at Austin , Austin, Texas , USA
| | - Arun Y Bohm
- b Department of Neuroscience and The Waggoner Center for Alcohol and Addiction Research , The University of Texas at Austin , Austin, Texas , USA
| | - Nigel S Atkinson
- b Department of Neuroscience and The Waggoner Center for Alcohol and Addiction Research , The University of Texas at Austin , Austin, Texas , USA
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Patananan AN, Budenholzer LM, Eskin A, Torres ER, Clarke SG. Ethanol-induced differential gene expression and acetyl-CoA metabolism in a longevity model of the nematode Caenorhabditis elegans. Exp Gerontol 2014; 61:20-30. [PMID: 25449858 DOI: 10.1016/j.exger.2014.11.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 09/17/2014] [Accepted: 11/16/2014] [Indexed: 01/09/2023]
Abstract
Previous studies have shown that exposing adults of the soil-dwelling nematode Caenorhabditis elegans to concentrations of ethanol in the range of 100-400mM results in slowed locomotion, decreased fertility, and reduced longevity. On the contrary, lower concentrations of ethanol (0.86-68mM) have been shown to cause a two- to three-fold increase in the life span of animals in the stress resistant L1 larval stage in the absence of a food source. However, little is known about how gene and protein expression is altered by low concentrations of ethanol and the mechanism for the increased longevity. Therefore, we used biochemical assays and next generation mRNA sequencing to identify genes and biological pathways altered by ethanol. RNA-seq analysis of L1 larvae incubated in the presence of 17mM ethanol resulted in the significant differential expression of 649 genes, 274 of which were downregulated and 375 were upregulated. Many of the genes significantly altered were associated with the conversion of ethanol and triglycerides to acetyl-CoA and glucose, suggesting that ethanol is serving as an energy source in the increased longevity of the L1 larvae as well as a signal for fat utilization. We also asked if L1 larvae could sense ethanol and respond by directed movement. Although we found that L1 larvae can chemotax to benzaldehyde, we observed little or no chemotaxis to ethanol. Understanding how low concentrations of ethanol increase the lifespan of L1 larvae may provide insight into not only the longevity pathways in C. elegans, but also in those of higher organisms.
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Affiliation(s)
| | | | - Ascia Eskin
- Department of Human Genetics, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA.
| | - Eric Rommel Torres
- Department of Chemistry and Biochemistry, Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA.
| | - Steven Gerard Clarke
- Department of Chemistry and Biochemistry, Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA.
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Dillon J, Andrianakis I, Mould R, Ient B, Liu W, James C, O'Connor V, Holden-Dye L. Distinct molecular targets including SLO-1 and gap junctions are engaged across a continuum of ethanol concentrations in Caenorhabditis elegans. FASEB J 2013; 27:4266-78. [PMID: 23882127 DOI: 10.1096/fj.11-189340] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Ethanol (alcohol) interacts with diverse molecular effectors across a range of concentrations in the brain, eliciting intoxication through to sedation. Invertebrate models including the nematode worm Caenorhabditis elegans have been deployed for molecular genetic studies to inform on key components of these alcohol signaling pathways. C. elegans studies have typically employed external dosing with high (>250 mM) ethanol concentrations: A careful analysis of responses to low concentrations is lacking. Using the C. elegans pharyngeal system as a paradigm, we report a previously uncharacterized continuum of cellular and behavioral responses to ethanol from low (10 mM) to high (300 mM) concentrations. The complexity of these responses indicates that the pleiotropic action of ethanol observed in mammalian brain is conserved in this invertebrate model. We investigated two candidate ethanol effectors, the calcium-activated K(+) channel SLO-1 and gap junctions, and show that they contribute to, but are not sole determinants of, the low- and high-concentration effects, respectively. Notably, this study shows cellular and whole organismal behavioral responses to ethanol in C. elegans that directly equate to intoxicating through to supralethal blood alcohol concentrations in humans and provides an important benchmark for interpretation of paradigms that seek to inform on human alcohol use disorders.
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Affiliation(s)
- James Dillon
- 1Current address: Institute of Digital Healthcare, Warwick Manufacturing Group, University of Warwick, Coventry CV4 7AL, UK
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Abstract
Alcohol consumption dates back to the Neolithic period, and alcohol dependence contributes substantially to the current global burden of disease. Despite this, optimal therapies and preventive strategies are lacking. Formal genetic studies of alcohol dependence have shown that genetic factors play as large a role in disease etiology as environmental factors. Molecular genetic studies may identify causal factors and facilitate the development of novel preventive and therapeutic approaches. Whereas earlier studies involved the use of linkage- and candidate-gene approaches, recent years have witnessed the introduction of genome-wide association studies (GWAS). The present review provides a brief overview of the findings of formal genetic studies, summarizes the results of earlier molecular-genetic investigations, and presents a detailed overview of all published GWAS in the field of alcohol dependence research. To date, few genome-wide significant findings have been reported. However, through the polygenic approach, GWAS have both confirmed the existence of a multitude of novel risk genes and indicated interesting new candidates.
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Affiliation(s)
- Marcella Rietschel
- Department of Genetic Epidemiology in Psychiatry, Central Institute of Mental Health Mannheim, University Medical Center Mannheim, University of Heidelberg, Germany.
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Kendler KS, Kalsi G, Holmans PA, Sanders AR, Aggen SH, Dick DM, Aliev F, Shi J, Levinson DF, Gejman PV. Genomewide association analysis of symptoms of alcohol dependence in the molecular genetics of schizophrenia (MGS2) control sample. Alcohol Clin Exp Res 2011; 35:963-75. [PMID: 21314694 PMCID: PMC3083473 DOI: 10.1111/j.1530-0277.2010.01427.x] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
BACKGROUND While genetic influences on alcohol dependence (AD) are substantial, progress in the identification of individual genetic variants that impact on risk has been difficult. METHODS We performed a genome-wide association study on 3,169 alcohol consuming subjects from the population-based Molecular Genetics of Schizophrenia (MGS2) control sample. Subjects were asked 7 questions about symptoms of AD which were analyzed by confirmatory factor analysis. Genotyping was performed using the Affymetrix 6.0 array. Three sets of analyses were conducted separately for European American (EA, n = 2,357) and African-American (AA, n = 812) subjects: individual single nucleotide polymorphisms (SNPs), candidate genes and enriched pathways using gene ontology (GO) categories. RESULTS The symptoms of AD formed a highly coherent single factor. No SNP approached genome-wide significance. In the EA sample, the most significant intragenic SNP was in KCNMA1, the human homolog of the slo-1 gene in C. Elegans. Genes with clusters of significant SNPs included AKAP9, phosphatidylinositol glycan anchor biosynthesis, class G (PIGG), and KCNMA1. In the AA sample, the most significant intragenic SNP was CEACAM6 and genes showing empirically significant SNPs included KCNQ5, SLC35B4, and MGLL. In the candidate gene based analyses, the most significant findings were with ADH1C, nuclear factor of kappa light polypeptide gene enhancer in B-cells 1 (NFKB1) and ankyrin repeat and kinase domain containing 1 (ANKK1) in the EA sample, and ADH5, POMC, and CHRM2 in the AA sample. The ALIGATOR program identified a significant excess of associated SNPs within and near genes in a substantial number of GO categories over a range of statistical stringencies in both the EA and AA sample. CONCLUSIONS While we cannot be highly confident about any single result from these analyses, a number of findings were suggestive and worthy of follow-up. Although quite large samples will be needed to obtain requisite power, the study of AD symptoms in general population samples is a viable complement to case-control studies in identifying genetic risk variants for AD.
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Affiliation(s)
- Kenneth S Kendler
- Virginia Institute of Psychiatric and Behavioral Genetics, Department of Psychiatry, Virginia Commonwealth University School of Medicine, Richmond, 23298, USA.
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Ehlers CL, Walter NAR, Dick DM, Buck KJ, Crabbe JC. A comparison of selected quantitative trait loci associated with alcohol use phenotypes in humans and mouse models. Addict Biol 2010; 15:185-99. [PMID: 20148779 DOI: 10.1111/j.1369-1600.2009.00195.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Evidence for genetic linkage to alcohol and other substance dependence phenotypes in areas of the human and mouse genome have now been reported with some consistency across studies. However, the question remains as to whether the genes that underlie the alcohol-related behaviors seen in mice are the same as those that underlie the behaviors observed in human alcoholics. The aims of the current set of analyses were to identify a small set of alcohol-related phenotypes in human and in mouse by which to compare quantitative trait locus (QTL) data between the species using syntenic mapping. These analyses identified that QTLs for alcohol consumption and acute and chronic alcohol withdrawal on distal mouse chromosome 1 are syntenic to a region on human chromosome 1q where a number of studies have identified QTLs for alcohol-related phenotypes. Additionally, a QTL on human chromosome 15 for alcohol dependence severity/withdrawal identified in two human studies was found to be largely syntenic with a region on mouse chromosome 9, where two groups have found QTLs for alcohol preference. In both of these cases, while the QTLs were found to be syntenic, the exact phenotypes between humans and mice did not necessarily overlap. These studies demonstrate how this technique might be useful in the search for genes underlying alcohol-related phenotypes in multiple species. However, these findings also suggest that trying to match exact phenotypes in humans and mice may not be necessary or even optimal for determining whether similar genes influence a range of alcohol-related behaviors between the two species.
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Affiliation(s)
- Cindy L Ehlers
- Department of Molecular and Integrative Neurosciences, The Scripps Research Institute, La Jolla, CA 92037, USA.
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Martin GE. BK channel and alcohol, a complicated affair. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2010; 91:321-38. [PMID: 20813247 DOI: 10.1016/s0074-7742(10)91010-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Alcohol is a fast acting molecule that alters behavior within a few minutes of absorption. Its rapid behavioral impact suggests early action on ion channels. Of all voltage-gated potassium ion channels, BK channels, a subcategory of potassium channels characterized by their large unitary conductance, and by their capacity of being activated synergistically by membrane potential and intracellular free calcium, are unique due to their high sensitivity to alcohol. In this review, we discuss BK channels structure and function, and how they help us understand the various ways BK channel mediates alcohol's effects on neuronal function and on behavior in the striatum.
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Affiliation(s)
- Gilles Erwan Martin
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA
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13
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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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Xie J. Control of alternative pre-mRNA splicing by Ca(++) signals. BIOCHIMICA ET BIOPHYSICA ACTA 2008; 1779:438-52. [PMID: 18258215 PMCID: PMC3500379 DOI: 10.1016/j.bbagrm.2008.01.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Revised: 12/18/2007] [Accepted: 01/08/2008] [Indexed: 02/06/2023]
Abstract
Alternative pre-mRNA splicing is a common way of gene expression regulation in metazoans. The selective use of specific exons can be modulated in response to various manipulations that alter Ca(++) signals, particularly in neurons. A number of splicing factors have also been found to be controlled by Ca(++) signals. Moreover, pre-mRNA elements have been identified that are essential and sufficient to mediate Ca(++)-regulated splicing, providing model systems for dissecting the involved molecular components. In neurons, this regulation likely contributes to the fine-tuning of neuronal properties.
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Affiliation(s)
- Jiuyong Xie
- Department of Physiology, Faculty of Medicine, University of Manitoba, 730 William Avenue, Winnipeg, Canada MB R3E 3J7.
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15
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Hong M, Choi MK, Lee J. The anesthetic action of ethanol analyzed by genetics in Caenorhabditis elegans. Biochem Biophys Res Commun 2008; 367:219-25. [DOI: 10.1016/j.bbrc.2007.12.133] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Accepted: 12/20/2007] [Indexed: 11/27/2022]
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Mitchell PH, Bull K, Glautier S, Hopper NA, Holden-Dye L, O'Connor V. The concentration-dependent effects of ethanol on Caenorhabditis elegans behaviour. THE PHARMACOGENOMICS JOURNAL 2007; 7:411-7. [PMID: 17325734 DOI: 10.1038/sj.tpj.6500440] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The effects of ethanol on the brain are concentration dependent. Low concentrations (mM) intoxicate, while greater than 100 mM anaesthetize. Of most relevance to human alcohol addiction are mechanisms of intoxication. Previously, Caenorhabditis elegans has been employed in genetic screens to define effectors of intoxication. Here, we inform interpretation of these studies by providing evidence that ethanol rapidly equilibriates across C. elegans cuticle. Importantly, the effect of ethanol on muscle activity rapidly reaches steady-state, and the concentration-dependence of the effect is very similar in intact animals and exposed muscle. Thus the cuticle does not present an absorption barrier for ethanol, and furthermore the internal concentration is likely to approach that applied externally. Thus, modelling intoxication in C. elegans requires exposure to external ethanol less than 100 mM. Furthermore, the permeability of the cuticle to ethanol enables analysis of precisely controlled concentration-dependent effects of acute, chronic, and episodic ethanol exposure on behaviour.
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Affiliation(s)
- P H Mitchell
- School of Biological Sciences, Bassett Crescent East, University of Southampton, Southampton UK
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17
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Artal-Sanz M, de Jong L, Tavernarakis N. Caenorhabditis elegans: a versatile platform for drug discovery. Biotechnol J 2007; 1:1405-18. [PMID: 17109493 DOI: 10.1002/biot.200600176] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Drug discovery and drug target identification are two intimately linked facets of intervention strategies aimed at effectively combating pathological conditions in humans. Simple model organisms provide attractive platforms for devising and streamlining efficient drug discovery and drug target identification methodologies. The nematode worm Caenorhabditis elegans has emerged as a particularly convenient and versatile tool that can be exploited to achieve these goals. Although C. elegans is a relatively modern addition to the arsenal of model organisms, its biology has already been investigated to an exceptional level. This, coupled with effortless handling and a notable low cost of cultivation and maintenance, allows seamless implementation of high-throughput drug screening approaches as well as in-depth genetic and biochemical studies of the molecular pathways targeted by specific drugs. In this review, we introduce C. elegans as a model organism with significant advantages toward the identification of molecular drug targets. In addition, we discuss the value of the worm in the development of drug screening and drug evaluation protocols. The unique features of C. elegans, which greatly facilitate drug studies, hold promise for both deciphering disease pathogenesis and formulating educated and effective therapeutic interventions.
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Affiliation(s)
- Marta Artal-Sanz
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, Hellas, Crete, Greece
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18
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Savel J, Clostre F. [A Nematode Nobel Prize: Caenorhabditis elegans]. ANNALES PHARMACEUTIQUES FRANÇAISES 2006; 64:291-307. [PMID: 17095949 DOI: 10.1016/s0003-4509(06)75322-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Nematode Caenorhabditis elegans (C. elegans) is an established model increasingly used for studying human disease pathogenesis. C. elegans models are based on the mutagenesis of human disease genes conserved in this Nematode or on the transgenesis with disease genes not conserved in C. elegans. Genetic examinations will give new insights on the cellular and molecular mechanisms that are altered in some neurodegenerative diseases like Duchenne's muscular dystrophy, Huntington's disease and Alzheimer's disease. C. elegans may be used for primary screening of new compounds that may be used as drugs in these diseases.
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Affiliation(s)
- J Savel
- Membre de l'Académie nationale de pharmacie, BP 68, F 75261 Paris Cedex 06
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19
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Alakoskela JM, Covey DF, Kinnunen PKJ. Lack of enantiomeric specificity in the effects of anesthetic steroids on lipid bilayers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1768:131-45. [PMID: 16945324 DOI: 10.1016/j.bbamem.2006.07.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2006] [Revised: 07/13/2006] [Accepted: 07/19/2006] [Indexed: 11/20/2022]
Abstract
The most important target protein for many anesthetics, including volatile and steroid anesthetics, appears to be the type A gamma-amino butyric acid receptor (GABA(A)R), yet direct binding remains to be demonstrated. Hypotheses of lipid-mediated anesthesia suggest that lipid bilayer properties are changed by anesthetics and that this in turn affects the functions of proteins. While other data could equally well support direct or lipid-mediated action, enantiomeric specificity displayed by some anesthetics is not reflected in their interactions with lipids. In the present study, we studied the effects of two pairs of anesthetic steroid enantiomers on bilayers of several compositions, measuring potentially relevant physical properties. For one of the pairs, allopregnanolone and ent-allopregnanolone, the natural enantiomer is 300% more efficacious as an anesthetic, while for the other, pregnanolone and ent-pregnanolone, there is little difference in anesthetic potency. For each enantiomer pair, we could find no differences. This strongly favors the view that the effects of these anesthetics on lipid bilayers are not relevant for the main features of anesthesia. These steroids also provide tools to distinguish in general the direct binding of steroids to proteins from lipid-mediated effects.
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Affiliation(s)
- Juha-Matti Alakoskela
- Helsinki Biophysics and Biomembrane Group, Institute of Biomedicine/Biochemistry, P.O. Box 63, 00014 University of Helsinki, Finland.
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Del Re AM, Dopico AM, Woodward JJ. Effects of the abused inhalant toluene on ethanol-sensitive potassium channels expressed in oocytes. Brain Res 2006; 1087:75-82. [PMID: 16626657 DOI: 10.1016/j.brainres.2006.03.031] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Revised: 03/09/2006] [Accepted: 03/13/2006] [Indexed: 11/23/2022]
Abstract
Toluene (methylbenzene) is representative of a class of industrial solvents that are voluntarily inhaled as drugs of abuse. Previous data from this laboratory and others have shown that these compounds alter the function of a variety of ion channels including ligand-gated channels activated by ATP, acetylcholine, GABA, glutamate and serotonin, as well as voltage-dependent sodium and calcium channels. It is less clear what effects toluene may have on potassium channels that act to reduce the excitability of most cells. Previous studies have shown that ethanol potentiates the function of both the large conductance, calcium-activated potassium channel (BK) and specific members of the G-protein-coupled inwardly rectifying potassium channels (GirKs). Since toluene and other abused inhalants share many behavioral effects with ethanol, it was hypothesized that toluene would also enhance the function of these channels. This hypothesis was tested using two-electrode voltage-clamp electrophysiology to measure the activity of BK and GirK potassium channel currents expressed in Xenopus laevis oocytes. As reported previously, ethanol potentiated currents in oocytes expressing either BK or GirK2 channels. In contrast, toluene caused a concentration-dependent inhibition of BK channel currents with 3 mM producing approximately 50% inhibition of control currents. Currents in oocytes injected with GirK2 mRNA were also inhibited by toluene while those expressing GirK1/2 and 1/4 channels were minimally affected. In oocytes co-injected with mRNA for GirK2 and the mGluR1a metabotropic receptor, exposure to glutamate potentiated currents evoked by a high-potassium solution. Toluene inhibited these glutamate-activated currents to approximately the same degree as those induced under basal conditions. The results of these studies show that toluene has effects on BK and GirK channels that are opposite to those of ethanol, suggesting that these channels are unlikely to underlie behaviors that these two drugs of abuse share.
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Affiliation(s)
- Angelo M Del Re
- Department of Neurosciences and Center for Drug and Alcohol Programs, Medical University of South Carolina, 173 Ashley Avenue, Suite 403, Charleston, 29425, USA
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Liu J, Asuncion-Chin M, Liu P, Dopico AM. CaM kinase II phosphorylation of slo Thr107 regulates activity and ethanol responses of BK channels. Nat Neurosci 2005; 9:41-9. [PMID: 16341213 PMCID: PMC2574430 DOI: 10.1038/nn1602] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2005] [Accepted: 10/21/2005] [Indexed: 01/01/2023]
Abstract
High-conductance, Ca(2+)-activated and voltage-gated (BK) channels set neuronal firing. They are almost universally activated by alcohol, leading to reduced neuronal excitability and neuropeptide release and to motor intoxication. However, several BK channels are inhibited by alcohol, and most other voltage-gated K(+) channels are refractory to drug action. BK channels are homotetramers (encoded by Slo1) that possess a unique transmembrane segment (S0), leading to a cytosolic S0-S1 loop. We identified Thr107 of bovine slo (bslo) in this loop as a critical residue that determines BK channel responses to alcohol. In addition, the activity of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) in the cell controlled channel activity and alcohol modulation. Incremental CaMKII-mediated phosphorylation of Thr107 in the BK tetramer progressively increased channel activity and gradually switched the channel alcohol responses from robust activation to inhibition. Thus, CaMKII phosphorylation of slo Thr107 works as a 'molecular dimmer switch' that could mediate tolerance to alcohol, a form of neuronal plasticity.
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Affiliation(s)
- Jianxi Liu
- Department of Pharmacology, University of Tennessee Health Science Center, 874 Union Avenue, Memphis, Tennessee 38163, USA
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Cowmeadow RB, Krishnan HR, Atkinson NS. The slowpoke gene is necessary for rapid ethanol tolerance in Drosophila. Alcohol Clin Exp Res 2005; 29:1777-86. [PMID: 16269907 DOI: 10.1097/01.alc.0000183232.56788.62] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Ethanol is one of the most commonly used drugs in the world. We are interested in the compensatory mechanisms used by the nervous system to counter the effects of ethanol intoxication. Recently, the slowpoke BK-type calcium-activated potassium channel gene has been shown to be involved in ethanol sensitivity in Caenorhabditis elegans and in rapid tolerance to the anesthetic benzyl alcohol in Drosophila. METHODS We used Drosophila mutants to investigate the role of slowpoke in rapid tolerance to sedation with ethanol vapor. Rapid tolerance was defined as a reduction in the sedative phase caused by a single previous sedation. The ethanol and water contents of flies were measured to determine if pharmacodynamic changes could account for tolerance. RESULTS A saturated ethanol air stream caused sedation in <20 min and resulted in rapid tolerance that was apparent 4 hr after sedation. Two independently isolated null mutations in the slowpoke gene eliminated the capacity for tolerance. In addition, a third mutation that blocked expression specifically in the nervous system also blocked rapid tolerance. Water measurements showed that both ethanol and mock sedation caused equivalent dehydration. Furthermore, a single prior exposure to ethanol did not cause a change in the ethanol clearance rate. CONCLUSIONS Rapid tolerance, measured as a reduction in the duration of sedation, is a pharmacokinetic response to ethanol that does not occur without slowpoke expression in the nervous system in Drosophila. The slowpoke channel must be involved in triggering or producing a homeostatic mechanism that opposes the sedative effects of ethanol.
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Affiliation(s)
- R B Cowmeadow
- Section of Neurobiology and The Waggoner Center for Alcohol and Addiction Research, University of Texas at Austin, Austin, Texas 78712-0248, USA
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Xiao ZM, Li LJ, Yu SZ, Lu ZN, Li CY, Zheng JQ. Effects of extracellular Ca(2+) influx and intracellular Ca(2+) release on ethanol-induced cytoplasmic Ca(2+) overload in cultured superior cervical ganglion neurons. Neurosci Lett 2005; 390:98-103. [PMID: 16115728 DOI: 10.1016/j.neulet.2005.08.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2005] [Revised: 07/19/2005] [Accepted: 08/01/2005] [Indexed: 10/25/2022]
Abstract
The present research was designed to investigate the interference of Ca(2+) homeostasis by ethanol on the primary cultured superior cervical ganglion (SCG) neurons. (1) Using the whole cell patch clamp recording, the amplitudes of voltage-dependent Ca(2+) channel (VDCC) currents could be reduced by ethanol in a concentration-dependent manner. Ethanol (100mM) inhibited about 25% of Ca(2+) channel current. However, the activation of Ca(2+) channel was not affected by ethanol at those concentrations. (2) The similar extent inhibitions of 100mM ethanol on the increments of intracellular Ca(2+) concentration ([Ca(2+)](i)) induced by 40 mM KCl and 1 microM A23187 were also observed in the fluo-3-AM loaded superior cervical ganglia (SCG) via detecting the change of [Ca(2+)](i) with a laser scanning confocal microscopy. In contrast, the basal [Ca(2+)](i) was significantly increased by ethanol alone in a concentration-dependent manner. These phenomena were also observed even under Ca(2+) free bath solution or the solution added 300 microM cadmium chloride conditions. Together with above results, our data suggest that ethanol increases basal [Ca(2+)](i), but it also inhibits the extracellular Ca(2+) influx through VDCC and ionophore channel. And the augment of basal [Ca(2+)](i) induced by ethanol might attribute to the Ca(2+) releasing from intracellular Ca(2+) pools.
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Affiliation(s)
- Zhe-Man Xiao
- Department of Neurology, Institution of Neuropsychiatry Research, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei, PR China.
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