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De Sa Nogueira D, Bourdy R, Alcala-Vida R, Filliol D, Andry V, Goumon Y, Zwiller J, Romieu P, Merienne K, Olmstead MC, Befort K. Hippocampal Cannabinoid 1 Receptors Are Modulated Following Cocaine Self-administration in Male Rats. Mol Neurobiol 2022; 59:1896-1911. [PMID: 35032317 DOI: 10.1007/s12035-022-02722-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 12/30/2021] [Indexed: 02/07/2023]
Abstract
Cocaine addiction is a complex pathology inducing long-term neuroplastic changes that, in turn, contribute to maladaptive behaviors. This behavioral dysregulation is associated with transcriptional reprogramming in brain reward circuitry, although the mechanisms underlying this modulation remain poorly understood. The endogenous cannabinoid system may play a role in this process in that cannabinoid mechanisms modulate drug reward and contribute to cocaine-induced neural adaptations. In this study, we investigated whether cocaine self-administration induces long-term adaptations, including transcriptional modifications and associated epigenetic processes. We first examined endocannabinoid gene expression in reward-related brain regions of the rat following self-administered (0.33 mg/kg intravenous, FR1, 10 days) cocaine injections. Interestingly, we found increased Cnr1 expression in several structures, including prefrontal cortex, nucleus accumbens, dorsal striatum, hippocampus, habenula, amygdala, lateral hypothalamus, ventral tegmental area, and rostromedial tegmental nucleus, with most pronounced effects in the hippocampus. Endocannabinoid levels, measured by mass spectrometry, were also altered in this structure. Chromatin immunoprecipitation followed by qPCR in the hippocampus revealed that two activating histone marks, H3K4Me3 and H3K27Ac, were enriched at specific endocannabinoid genes following cocaine intake. Targeting CB1 receptors using chromosome conformation capture, we highlighted spatial chromatin re-organization in the hippocampus, as well as in the nucleus accumbens, suggesting that destabilization of the chromatin may contribute to neuronal responses to cocaine. Overall, our results highlight a key role for the hippocampus in cocaine-induced plasticity and broaden the understanding of neuronal alterations associated with endocannabinoid signaling. The latter suggests that epigenetic modifications contribute to maladaptive behaviors associated with chronic drug use.
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Affiliation(s)
- David De Sa Nogueira
- Laboratoire de Neurosciences Cognitives Et Adaptatives (LNCA), Centre de La Recherche Nationale Scientifique, Université de Strasbourg, 12 rue Goethe, 67000, Strasbourg, France.,Brain Health Institute, Rutgers University and Rutgers Biomedical and Health Sciences, 683 Hoes Lane West, Piscataway, NJ, 08854, USA
| | - Romain Bourdy
- Laboratoire de Neurosciences Cognitives Et Adaptatives (LNCA), Centre de La Recherche Nationale Scientifique, Université de Strasbourg, 12 rue Goethe, 67000, Strasbourg, France
| | - Rafael Alcala-Vida
- Laboratoire de Neurosciences Cognitives Et Adaptatives (LNCA), Centre de La Recherche Nationale Scientifique, Université de Strasbourg, 12 rue Goethe, 67000, Strasbourg, France
| | - Dominique Filliol
- Laboratoire de Neurosciences Cognitives Et Adaptatives (LNCA), Centre de La Recherche Nationale Scientifique, Université de Strasbourg, 12 rue Goethe, 67000, Strasbourg, France
| | - Virginie Andry
- Institut Des Neurosciences Cellulaires Et Intégratives (INCI), UPR 3212, CNRS, 8 Allée du Général Rouvillois, 67000, Strasbourg, France
| | - Yannick Goumon
- Institut Des Neurosciences Cellulaires Et Intégratives (INCI), UPR 3212, CNRS, 8 Allée du Général Rouvillois, 67000, Strasbourg, France
| | - Jean Zwiller
- Laboratoire de Neurosciences Cognitives Et Adaptatives (LNCA), Centre de La Recherche Nationale Scientifique, Université de Strasbourg, 12 rue Goethe, 67000, Strasbourg, France
| | - Pascal Romieu
- Laboratoire de Neurosciences Cognitives Et Adaptatives (LNCA), Centre de La Recherche Nationale Scientifique, Université de Strasbourg, 12 rue Goethe, 67000, Strasbourg, France
| | - Karine Merienne
- Laboratoire de Neurosciences Cognitives Et Adaptatives (LNCA), Centre de La Recherche Nationale Scientifique, Université de Strasbourg, 12 rue Goethe, 67000, Strasbourg, France
| | - Mary C Olmstead
- Department of Psychology, Center for Neuroscience Studies, Queen's University, Kingston, ON, K7L 3N6, Canada
| | - Katia Befort
- Laboratoire de Neurosciences Cognitives Et Adaptatives (LNCA), Centre de La Recherche Nationale Scientifique, Université de Strasbourg, 12 rue Goethe, 67000, Strasbourg, France.
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De Sa Nogueira D, Bourdy R, Filliol D, Romieu P, Befort K. Hippocampal mu opioid receptors are modulated following cocaine self-administration in rat. Eur J Neurosci 2021; 53:3341-3349. [PMID: 33811699 DOI: 10.1111/ejn.15217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 03/18/2021] [Indexed: 11/30/2022]
Abstract
Cocaine addiction is a complex pathology induced by long-term brain changes. Understanding the neurochemical changes underlying the reinforcing effects of this drug of abuse is critical for reducing the societal burden of drug addiction. The mu opioid receptor plays a major role in drug reward. This receptor is modulated by chronic cocaine treatment in specific brain structures, but few studies investigated neurochemical adaptations induced by voluntary cocaine intake. In this study, we investigated whether intravenous cocaine-self administration (0.33 mg/kg/injection, fixed-ratio 1 [FR1], 10 days) in rats induces transcriptional and functional changes of the mu opioid receptor in reward-related brain regions. Epigenetic processes with histone modifications were examined for two activating marks, H3K4Me3, and H3K27Ac. We found an increase of mu opioid receptor gene expression along with a potentiation of its functionality in hippocampus of cocaine self-administering animals compared to saline controls. Chromatin immunoprecipitation followed by qPCR revealed no modifications of the histone mark H3K4Me3 and H3K27Ac levels at mu opioid receptor promoter. Our study highlights the hippocampus as an important target to further investigate neuroadaptive processes leading to cocaine addiction.
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Affiliation(s)
- David De Sa Nogueira
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA UMR7364), Centre de la Recherche Nationale Scientifique, Université de Strasbourg, Strasbourg, France
| | - Romain Bourdy
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA UMR7364), Centre de la Recherche Nationale Scientifique, Université de Strasbourg, Strasbourg, France
| | - Dominique Filliol
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA UMR7364), Centre de la Recherche Nationale Scientifique, Université de Strasbourg, Strasbourg, France
| | - Pascal Romieu
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA UMR7364), Centre de la Recherche Nationale Scientifique, Université de Strasbourg, Strasbourg, France
| | - Katia Befort
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA UMR7364), Centre de la Recherche Nationale Scientifique, Université de Strasbourg, Strasbourg, France
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Johnstone AL, Andrade NS, Barbier E, Khomtchouk BB, Rienas CA, Lowe K, Van Booven DJ, Domi E, Esanov R, Vilca S, Tapocik JD, Rodriguez K, Maryanski D, Keogh MC, Meinhardt MW, Sommer WH, Heilig M, Zeier Z, Wahlestedt C. Dysregulation of the histone demethylase KDM6B in alcohol dependence is associated with epigenetic regulation of inflammatory signaling pathways. Addict Biol 2021; 26:e12816. [PMID: 31373129 PMCID: PMC7757263 DOI: 10.1111/adb.12816] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 05/28/2019] [Accepted: 07/09/2019] [Indexed: 12/20/2022]
Abstract
Epigenetic enzymes oversee long‐term changes in gene expression by integrating genetic and environmental cues. While there are hundreds of enzymes that control histone and DNA modifications, their potential roles in substance abuse and alcohol dependence remain underexplored. A few recent studies have suggested that epigenetic processes could underlie transcriptomic and behavioral hallmarks of alcohol addiction. In the present study, we sought to identify epigenetic enzymes in the brain that are dysregulated during protracted abstinence as a consequence of chronic and intermittent alcohol exposure. Through quantitative mRNA expression analysis of over 100 epigenetic enzymes, we identified 11 that are significantly altered in alcohol‐dependent rats compared with controls. Follow‐up studies of one of these enzymes, the histone demethylase KDM6B, showed that this enzyme exhibits region‐specific dysregulation in the prefrontal cortex and nucleus accumbens of alcohol‐dependent rats. KDM6B was also upregulated in the human alcoholic brain. Upregulation of KDM6B protein in alcohol‐dependent rats was accompanied by a decrease of trimethylation levels at histone H3, lysine 27 (H3K27me3), consistent with the known demethylase specificity of KDM6B. Subsequent epigenetic (chromatin immunoprecipitation [ChIP]–sequencing) analysis showed that alcohol‐induced changes in H3K27me3 were significantly enriched at genes in the IL‐6 signaling pathway, consistent with the well‐characterized role of KDM6B in modulation of inflammatory responses. Knockdown of KDM6B in cultured microglial cells diminished IL‐6 induction in response to an inflammatory stimulus. Our findings implicate a novel KDM6B‐mediated epigenetic signaling pathway integrated with inflammatory signaling pathways that are known to underlie the development of alcohol addiction.
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Affiliation(s)
- Andrea L. Johnstone
- Center for Therapeutic Innovation University of Miami Miller School of Medicine Miami Florida USA
- Department of Psychiatry and Behavioral Sciences University of Miami Miller School of Medicine Miami Florida USA
- Division of Product Development EpiCypher, Inc Durham North Carolina USA
| | - Nadja S. Andrade
- Department of Psychiatry and Behavioral Sciences University of Miami Miller School of Medicine Miami Florida USA
| | - Estelle Barbier
- Department of Clinical and Experimental Medicine, Division of Cell Biology, Faculty of Health Sciences Linköping University Linköping Sweden
| | - Bohdan B. Khomtchouk
- Center for Therapeutic Innovation University of Miami Miller School of Medicine Miami Florida USA
- Department of Psychiatry and Behavioral Sciences University of Miami Miller School of Medicine Miami Florida USA
- Department of Medicine, Section of Computational Biomedicine and Biomedical Data Science, Institute for Genomics and Systems Biology University of Chicago Chicago IL USA
| | - Christopher A. Rienas
- Center for Therapeutic Innovation University of Miami Miller School of Medicine Miami Florida USA
- Department of Psychiatry and Behavioral Sciences University of Miami Miller School of Medicine Miami Florida USA
| | - Kenneth Lowe
- Center for Therapeutic Innovation University of Miami Miller School of Medicine Miami Florida USA
- Department of Psychiatry and Behavioral Sciences University of Miami Miller School of Medicine Miami Florida USA
| | - Derek J. Van Booven
- John P. Hussman Institute for Human Genomics University of Miami Miller School of Medicine Miami Florida USA
| | - Esi Domi
- Department of Clinical and Experimental Medicine, Division of Cell Biology, Faculty of Health Sciences Linköping University Linköping Sweden
| | - Rustam Esanov
- Center for Therapeutic Innovation University of Miami Miller School of Medicine Miami Florida USA
- Department of Psychiatry and Behavioral Sciences University of Miami Miller School of Medicine Miami Florida USA
| | - Samara Vilca
- Center for Therapeutic Innovation University of Miami Miller School of Medicine Miami Florida USA
- Department of Psychiatry and Behavioral Sciences University of Miami Miller School of Medicine Miami Florida USA
| | - Jenica D. Tapocik
- Laboratory of Clinical and Translational Studies, National Institute on Alcohol Abuse and Alcoholism National Institutes of Health Bethesda Maryland USA
| | - Keli Rodriguez
- Division of Product Development EpiCypher, Inc Durham North Carolina USA
| | - Danielle Maryanski
- Division of Product Development EpiCypher, Inc Durham North Carolina USA
| | | | - Marcus W. Meinhardt
- Department of Psychopharmacology Central Institute of Mental Health, Heidelberg University Mannheim Germany
| | - Wolfgang H. Sommer
- Department of Psychopharmacology Central Institute of Mental Health, Heidelberg University Mannheim Germany
| | - Markus Heilig
- Department of Clinical and Experimental Medicine, Division of Cell Biology, Faculty of Health Sciences Linköping University Linköping Sweden
| | - Zane Zeier
- Center for Therapeutic Innovation University of Miami Miller School of Medicine Miami Florida USA
- Department of Psychiatry and Behavioral Sciences University of Miami Miller School of Medicine Miami Florida USA
| | - Claes Wahlestedt
- Center for Therapeutic Innovation University of Miami Miller School of Medicine Miami Florida USA
- Department of Psychiatry and Behavioral Sciences University of Miami Miller School of Medicine Miami Florida USA
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The striatal-enriched protein Rhes is a critical modulator of cocaine-induced molecular and behavioral responses. Sci Rep 2019; 9:15294. [PMID: 31653935 PMCID: PMC6814836 DOI: 10.1038/s41598-019-51839-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 10/09/2019] [Indexed: 12/31/2022] Open
Abstract
Previous evidence pointed out a role for the striatal-enriched protein Rhes in modulating dopaminergic transmission. Based on the knowledge that cocaine induces both addiction and motor stimulation, through its ability to enhance dopaminergic signaling in the corpus striatum, we have now explored the involvement of Rhes in the effects associated with this psychostimulant. Our behavioral data showed that a lack of Rhes in knockout animals caused profound alterations in motor stimulation following cocaine exposure, eliciting a significant leftward shift in the dose-response curve and triggering a dramatic hyperactivity. We also found that Rhes modulated either short- or long-term motor sensitization induced by cocaine, since lack of this protein prevents both of them in mutants. Consistent with this in vivo observation, we found that lack of Rhes in mice caused a greater increase in striatal cocaine-dependent D1R/cAMP/PKA signaling, along with considerable enhancement of Arc, zif268, and Homer1 mRNA expression. We also documented that lack of Rhes in mice produced cocaine-related striatal alterations in proteomic profiling, with a differential expression of proteins clustering in calcium homeostasis and cytoskeletal protein binding categories. Despite dramatic striatal alterations associated to cocaine exposure, our data did not reveal any significant changes in midbrain dopaminergic neurons as a lack of Rhes did not affect: (i) DAT activity; (ii) D2R-dependent regulation of GIRK; and (iii) D2R-dependent regulation of dopamine release. Collectively, our results strengthen the view that Rhes acts as a pivotal physiological “molecular brake” for striatal dopaminergic system overactivation induced by psychostimulants, thus making this protein of interest in regulating the molecular mechanism underpinning cocaine-dependent motor stimulatory effects.
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Wu X, Xie S, Wang L, Fan P, Ge S, Xie XQ, Wu W. A computational strategy for finding novel targets and therapeutic compounds for opioid dependence. PLoS One 2018; 13:e0207027. [PMID: 30403753 PMCID: PMC6221321 DOI: 10.1371/journal.pone.0207027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 10/22/2018] [Indexed: 12/13/2022] Open
Abstract
Opioids are widely used for treating different types of pains, but overuse and abuse of prescription opioids have led to opioid epidemic in the United States. Besides analgesic effects, chronic use of opioid can also cause tolerance, dependence, and even addiction. Effective treatment of opioid addiction remains a big challenge today. Studies on addictive effects of opioids focus on striatum, a main component in the brain responsible for drug dependence and addiction. Some transcription regulators have been associated with opioid addiction, but relationship between analgesic effects of opioids and dependence behaviors mediated by them at the molecular level has not been thoroughly investigated. In this paper, we developed a new computational strategy that identifies novel targets and potential therapeutic molecular compounds for opioid dependence and addiction. We employed several statistical and machine learning techniques and identified differentially expressed genes over time which were associated with dependence-related behaviors after exposure to either morphine or heroin, as well as potential transcription regulators that regulate these genes, using time course gene expression data from mouse striatum. Moreover, our findings revealed that some of these dependence-associated genes and transcription regulators are known to play key roles in opioid-mediated analgesia and tolerance, suggesting that an intricate relationship between opioid-induce pain-related pathways and dependence may develop at an early stage during opioid exposure. Finally, we determined small compounds that can potentially target the dependence-associated genes and transcription regulators. These compounds may facilitate development of effective therapy for opioid dependence and addiction. We also built a database (http://daportals.org) for all opioid-induced dependence-associated genes and transcription regulators that we discovered, as well as the small compounds that target those genes and transcription regulators.
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Affiliation(s)
- Xiaojun Wu
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Siwei Xie
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Lirong Wang
- Department of Pharmaceutical Sciences and Computational Chemical Genomics Screening Center, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Drug Discovery Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Peihao Fan
- Department of Pharmaceutical Sciences and Computational Chemical Genomics Screening Center, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Songwei Ge
- School of Information, Renmin University of China, Beijing, China
| | - Xiang-Qun Xie
- Department of Pharmaceutical Sciences and Computational Chemical Genomics Screening Center, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Drug Discovery Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Wei Wu
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
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De Sa Nogueira D, Merienne K, Befort K. Neuroepigenetics and addictive behaviors: Where do we stand? Neurosci Biobehav Rev 2018; 106:58-72. [PMID: 30205119 DOI: 10.1016/j.neubiorev.2018.08.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 07/28/2018] [Accepted: 08/29/2018] [Indexed: 12/21/2022]
Abstract
Substance use disorders involve long-term changes in the brain that lead to compulsive drug seeking, craving, and a high probability of relapse. Recent findings have highlighted the role of epigenetic regulations in controlling chromatin access and regulation of gene expression following exposure to drugs of abuse. In the present review, we focus on data investigating genome-wide epigenetic modifications in the brain of addicted patients or in rodent models exposed to drugs of abuse, with a particular focus on DNA methylation and histone modifications associated with transcriptional studies. We highlight critical factors for epigenomic studies in addiction. We discuss new findings related to psychostimulants, alcohol, opiate, nicotine and cannabinoids. We examine the possible transmission of these changes across generations. We highlight developing tools, specifically those that allow investigation of structural reorganization of the chromatin. These have the potential to increase our understanding of alteration of chromatin architecture at gene regulatory regions. Neuroepigenetic mechanisms involved in addictive behaviors could explain persistent phenotypic effects of drugs and, in particular, vulnerability to relapse.
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Affiliation(s)
- David De Sa Nogueira
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), UMR 7364, CNRS, Université de Strasbourg, Team 3 « Abuse of Drugs and Neuroadaptations », Faculté de Psychologie, 12 rue Goethe, F-67000, France
| | - Karine Merienne
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), UMR 7364, CNRS, Université de Strasbourg, Team 1 « Dynamics of Memory and Epigenetics », Faculté de Psychologie, 12 rue Goethe, F-67000, France
| | - Katia Befort
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), UMR 7364, CNRS, Université de Strasbourg, Team 3 « Abuse of Drugs and Neuroadaptations », Faculté de Psychologie, 12 rue Goethe, F-67000, France.
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Small molecule modulators of σ2R/Tmem97 reduce alcohol withdrawal-induced behaviors. Neuropsychopharmacology 2018; 43:1867-1875. [PMID: 29728649 PMCID: PMC6046036 DOI: 10.1038/s41386-018-0067-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 03/09/2018] [Accepted: 04/05/2018] [Indexed: 12/29/2022]
Abstract
Repeated cycles of intoxication and withdrawal enhance the negative reinforcing properties of alcohol and lead to neuroadaptations that underlie withdrawal symptoms driving alcohol dependence. Pharmacotherapies that target these neuroadaptations may help break the cycle of dependence. The sigma-1 receptor (σ1R) subtype has attracted interest as a possible modulator of the rewarding and reinforcing effects of alcohol. However, whether the sigma-2 receptor, recently cloned and identified as transmembrane protein 97 (σ2R/TMEM97), plays a role in alcohol-related behaviors is currently unknown. Using a Caenorhabditis elegans model, we identified two novel, selective σ2R/Tmem97 modulators that reduce alcohol withdrawal behavior via an ortholog of σ2R/TMEM97. We then show that one of these compounds blunted withdrawal-induced excessive alcohol drinking in a well-established rodent model of alcohol dependence. These discoveries provide the first evidence that σ2R/TMEM97 is involved in alcohol withdrawal behaviors and that this receptor is a potential new target for treating alcohol use disorder.
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Behavioral Deficits Following Withdrawal from Chronic Ethanol Are Influenced by SLO Channel Function in Caenorhabditis elegans. Genetics 2017; 206:1445-1458. [PMID: 28546434 DOI: 10.1534/genetics.116.193102] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 04/29/2017] [Indexed: 01/03/2023] Open
Abstract
Symptoms of withdrawal from chronic alcohol use are a driving force for relapse in alcohol dependence. Thus, uncovering molecular targets to lessen their severity is key to breaking the cycle of dependence. Using the nematode Caenorhabditis elegans, we tested whether one highly conserved ethanol target, the large-conductance, calcium-activated potassium channel (known as the BK channel or Slo1), modulates ethanol withdrawal. Consistent with a previous report, we found that C. elegans displays withdrawal-related behavioral impairments after cessation of chronic ethanol exposure. We found that the degree of impairment is exacerbated in worms lacking the worm BK channel, SLO-1, and is reduced by selective rescue of this channel in the nervous system. Enhanced SLO-1 function, via gain-of-function mutation or overexpression, also dramatically reduced behavioral impairment during withdrawal. Consistent with these results, we found that chronic ethanol exposure decreased SLO-1 expression in a subset of neurons. In addition, we found that the function of a distinct, conserved Slo family channel, SLO-2, showed an inverse relationship to withdrawal behavior, and this influence depended on SLO-1 function. Together, our findings show that modulation of either Slo family ion channel bidirectionally regulates withdrawal behaviors in worm, supporting further exploration of the Slo family as targets for normalizing behaviors during alcohol withdrawal.
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Abstract
Affective disorders such as anxiety, phobia and depression are a leading cause of disabilities worldwide. Monoamine neuromodulators are used to treat most of them, with variable degrees of efficacy. Here, we review and interpret experimental findings about the relation of neuromodulation and emotional feelings, in pursuit of two goals: (a) to improve the conceptualisation of affective/emotional states, and (b) to develop a descriptive model of basic emotional feelings related to the actions of neuromodulators. In this model, we hypothesize that specific neuromodulators are effective for basic emotions. The model can be helpful for mental health professionals to better understand the affective dynamics of persons and the actions of neuromodulators - and respective psychoactive drugs - on this dynamics.
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Affiliation(s)
- Fushun Wang
- Professor of Psychology, Director of the Institute of Emotional Psychology, Nanjing University of Traditional Medicine, 138 Xianlin Rd, Qixia district, Nanjing City, Jiangsu Province, China 210023. E-mail:
| | - Alfredo Pereira
- Adjunct Professor, Department of Education, São Paulo State University (UNESP), Campus of Rubião Jr, 18618-970 - Botucatu - São Paulo - Brasil
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10
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Williams SN, Undieh AS. Dopamine-sensitive signaling mediators modulate psychostimulant-induced ultrasonic vocalization behavior in rats. Behav Brain Res 2015; 296:1-6. [PMID: 26275925 DOI: 10.1016/j.bbr.2015.08.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Revised: 08/05/2015] [Accepted: 08/08/2015] [Indexed: 01/25/2023]
Abstract
The mesolimbic dopamine system plays a major role in psychostimulant-induced ultrasonic vocalization (USV) behavior in rodents. Within this system, psychostimulants elevate synaptic concentrations of dopamine thereby leading to exaggerated activation of postsynaptic dopamine receptors within the D1-like and D2-like subfamilies. Dopamine receptor stimulation activate several transmembrane signaling systems and cognate intracellular mediators; downstream activation of transcription factors then conveys the information from receptor activation to appropriate modulation of cellular and physiologic functions. We previously showed that cocaine-induced USV behavior was associated with enhanced expression of the neurotrophin BDNF. Like cocaine, amphetamine also increases synaptic dopamine levels, albeit primarily through facilitating dopamine release. Therefore, in the present study we investigated whether amphetamine and cocaine similarly activate dopamine-linked signaling cascades to regulate intracellular mediators leading to induction of USV behavior. The results show that amphetamine increased the emission of 50 kHz USVs and this effect was blocked by SCH23390, a D1 receptor antagonist. Similar to cocaine, amphetamine increased BDNF protein expression in discrete brain regions, while pretreatment with K252a, a trkB neurotrophin receptor inhibitor, significantly reduced amphetamine-induced USV behavior. Inhibition of cyclic-AMP/PKA signaling with H89 or inhibition of PLC signaling with U73122 significantly blocked both the acute and subchronic amphetamine-induced USV behavior. In contrast, pharmacologic inhibition of either pathway enhanced cocaine-induced USV behavior. Although cocaine and amphetamine similarly modulate neurotrophin expression and USV, the molecular mechanisms by which these psychostimulants differentially activate dopamine receptor subtypes or other monoaminergic systems may be responsible for the distinct aspects of behavioral responses.
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Affiliation(s)
- Stacey N Williams
- Department of Pharmaceutical Sciences, Notre Dame of Maryland University, School of Pharmacy, Baltimore, MD 21210, United States.
| | - Ashiwel S Undieh
- School of Medicine, City University of New York, City College, 160 Convent Avenue, New York, NY 10031, United States.
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11
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Chen J, Hutchison KE, Calhoun VD, Claus ED, Turner JA, Sui J, Liu J. CREB-BDNF pathway influences alcohol cue-elicited activation in drinkers. Hum Brain Mapp 2015; 36:3007-19. [PMID: 25939814 DOI: 10.1002/hbm.22824] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 04/13/2015] [Accepted: 04/15/2015] [Indexed: 01/01/2023] Open
Abstract
Alcohol use disorder (AUD) is suggested to have polygenic risk factors and also exhibits neurological complications, strongly encouraging a translational study to explore the associations between aggregates of genetic variants and brain function alterations related to alcohol use. In this study, we used a semiblind multivariate approach, parallel independent component analysis with multiple references (pICA-MR) to investigate relationships of genome-wide single nucleotide polymorphisms with alcohol cue-elicited brain activations in 315 heavy drinkers, where pICA-MR assesses multiple reference genes for their architecture and functional influences on neurobiological conditions. The genetic component derived from the cAMP-response element-binding protein and -brain derived neurotrophic factor (CREB-BDNF) pathway reference was significantly associated (r = -0.38, P = 3.98 × 10(-12) ) with an imaging component reflecting hyperactivation in precuneus, superior parietal lobule, and posterior cingulate for drinkers with more severe alcohol dependence symptoms. The highlighted brain regions participate in many cognitive processes and have been robustly implicated in craving-related studies. The genetic factor highlighted the CREB and BDNF references, as well as other genes including GRM5, GRM7, GRID1, GRIN2A, PRKCA, and PRKCB. Ingenuity Pathway Analysis indicated that the genetic component was enriched in synaptic plasticity, GABA, and protein kinase A signaling. Collectively, our findings suggest that genetic variations in various neural plasticity and signaling pathways partially explain the variance of precuneus reactivity to alcohol cues which appears to be associated with AUD severity.
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Affiliation(s)
- Jiayu Chen
- The Mind Research Network, Lovelace Biomedical and Environmental Research Institute, Albuquerque, New Mexico
| | - Kent E Hutchison
- The Mind Research Network, Lovelace Biomedical and Environmental Research Institute, Albuquerque, New Mexico.,Department of Psychology and Neuroscience, University of Colorado at Boulder, Boulder, Colorado
| | - Vince D Calhoun
- The Mind Research Network, Lovelace Biomedical and Environmental Research Institute, Albuquerque, New Mexico.,Department of Electrical Engineering, University of New Mexico, Albuquerque, New Mexico
| | - Eric D Claus
- The Mind Research Network, Lovelace Biomedical and Environmental Research Institute, Albuquerque, New Mexico
| | - Jessica A Turner
- The Mind Research Network, Lovelace Biomedical and Environmental Research Institute, Albuquerque, New Mexico.,Psychology Department and Neuroscience Institute, Georgia State University, Atlanta, Georgia
| | - Jing Sui
- The Mind Research Network, Lovelace Biomedical and Environmental Research Institute, Albuquerque, New Mexico.,Brainnetome Center and National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China
| | - Jingyu Liu
- The Mind Research Network, Lovelace Biomedical and Environmental Research Institute, Albuquerque, New Mexico.,Department of Electrical Engineering, University of New Mexico, Albuquerque, New Mexico
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Effects of biperiden on the treatment of cocaine/crack addiction: a randomised, double-blind, placebo-controlled trial. Eur Neuropsychopharmacol 2014; 24:1196-202. [PMID: 24974353 DOI: 10.1016/j.euroneuro.2014.06.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 05/23/2014] [Accepted: 06/02/2014] [Indexed: 11/24/2022]
Abstract
Cocaine use affects approximately 13.4 million people, or 0.3% of the world's population between 15 and 64 years of age. Several authors have described drug addiction as a disease of the brain reward system. Given that the cholinergic system impacts reward mechanisms and drug self-administration, acetylcholine (ACh) might play an important role in the cocaine addiction process. We evaluated the efficacy of biperiden (a cholinergic antagonist) in reducing craving and the amount used, and in increasing compliance with treatment for cocaine/crack addiction. It was a study double-blind, randomised, placebo-controlled, 8-week trial of 111 cocaine or crack addicted male patients between 18 and 50 years old. Two groups were compared: placebo (n=55) or biperiden (n=56) combined with weekly sessions of brief group cognitive-behavioural therapy. The efficacy of treatment was evaluated according to the patients' compliance and several instruments: the Minnesota Cocaine Craving Scale, the Beck Depression and Anxiety Scales and a questionnaire assessing the amount of drug used. All of the patients attended weekly sessions for two months. We analysed the data considering the patients' intention to treat based on our last observation. Of the 56 patients in the biperiden group, 24 completed the treatment (42.8%) compared with only 11 patients in the placebo group (20%), which was a significant difference (p=0.009). Compliance with treatment was 118% higher in the biperiden group, which was also the group that presented a statistically significant reduction in the amount of cocaine/crack use (p<0.001). There was statistically significant difference between the craving score in the biperiden group. Pharmacological blockade of the cholinergic system with biperiden is a promising alternative to treat cocaine/crack addiction, helping patients to reduce the amount used and improving compliance with psychotherapy treatment.
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13
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Prosser RA, Stowie A, Amicarelli M, Nackenoff AG, Blakely RD, Glass JD. Cocaine modulates mammalian circadian clock timing by decreasing serotonin transport in the SCN. Neuroscience 2014; 275:184-93. [PMID: 24950119 DOI: 10.1016/j.neuroscience.2014.06.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 06/06/2014] [Accepted: 06/07/2014] [Indexed: 12/15/2022]
Abstract
Cocaine abuse disrupts reward and homeostatic processes through diverse processes, including those involved in circadian clock regulation. Recently we showed that cocaine administration to mice disrupts nocturnal photic phase resetting of the suprachiasmatic (SCN) circadian clock, whereas administration during the day induces non-photic phase shifts. Importantly, the same effects are seen when cocaine is applied to the SCN in vitro, where it blocks photic-like (glutamate-induced) phase shifts at night and induces phase advances during the day. Furthermore, our previous data suggest that cocaine acts in the SCN by enhancing 5-HT signaling. For example, the in vitro actions of cocaine mimic those of 5-HT and are blocked by the 5-HT antagonist, metergoline, but not the dopamine receptor antagonist, fluphenazine. Although our data are consistent with cocaine acting through enhanced 5-HT signaling, the nonselective actions of cocaine as an antagonist of monoamine transporters raises the question of whether inhibition of the 5-HT transporter (SERT) is key to its circadian effects. Here we investigate this issue using transgenic mice expressing a SERT that exhibits normal 5-HT recognition and transport but significantly reduced cocaine potency (SERT Met172). Circadian patterns of SCN behavioral and neuronal activity did not differ between wild-type (WT) and SERT Met172 mice, nor did they differ in the ability of the 5-HT1A,2,7 receptor agonist, 8-OH-DPAT to reset SCN clock phase, consistent with the normal SERT expression and activity in the transgenic mice. However, (1) cocaine administration does not induce phase advances when administered in vivo or in vitro in SERT Met172 mice; (2) cocaine does not block photic or glutamate-induced phase shifts in SERT Met172 mice; and (3) cocaine does not induce long-term changes in free-running period in SERT Met172 mice. We conclude that SERT antagonism is required for the phase shifting of the SCN circadian clock induced by cocaine.
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Affiliation(s)
- R A Prosser
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA.
| | - A Stowie
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - M Amicarelli
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - A G Nackenoff
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, USA; Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, USA
| | - R D Blakely
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, USA; Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, USA
| | - J D Glass
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
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Lind PA, Zhu G, Montgomery GW, Madden PAF, Heath AC, Martin NG, Slutske WS. Genome-wide association study of a quantitative disordered gambling trait. Addict Biol 2013; 18:511-22. [PMID: 22780124 DOI: 10.1111/j.1369-1600.2012.00463.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Disordered gambling is a moderately heritable trait, but the underlying genetic basis is largely unknown. We performed a genome-wide association study (GWAS) for disordered gambling using a quantitative factor score in 1312 twins from 894 Australian families. Association was conducted for 2 381 914 single-nucleotide polymorphisms (SNPs) using the family-based association test in Merlin followed by gene and pathway enrichment analyses. Although no SNP reached genome-wide significance, six achieved P-values < 1 × 10(-5) with variants in three genes (MT1X, ATXN1 and VLDLR) implicated in disordered gambling. Secondary case-control analyses found two SNPs on chromosome 9 (rs1106076 and rs12305135 near VLDLR) and rs10812227 near FZD10 on chromosome 12 to be significantly associated with lifetime Diagnostic and Statistical Manual of Mental Disorders, fourth edition pathological gambling and South Oaks Gambling Screen classified probable pathological gambling status. Furthermore, several addiction-related pathways were enriched for SNPs associated with disordered gambling. Finally, gene-based analysis of 24 candidate genes for dopamine agonist-induced gambling in individuals with Parkinson's disease suggested an enrichment of SNPs associated with disordered gambling. We report the first GWAS of disordered gambling. While further replication is required, the identification of susceptibility loci and biological pathways will be important in characterizing the biological mechanisms that underpin disordered gambling.
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Affiliation(s)
- Penelope A Lind
- Quantitative Genetics, Queensland Institute of Medical Research, Brisbane, QLD, Australia
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15
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Periadolescent ethanol vapor exposure persistently reduces measures of hippocampal neurogenesis that are associated with behavioral outcomes in adulthood. Neuroscience 2013; 244:1-15. [PMID: 23567812 DOI: 10.1016/j.neuroscience.2013.03.058] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 03/25/2013] [Accepted: 03/26/2013] [Indexed: 01/23/2023]
Abstract
Excessive alcohol consumption is prevalent among adolescents and may result in lasting neurobehavioral consequences. The use of animal models to study adolescent alcohol exposure has the advantage of allowing for the control necessary in order to evaluate the effects of ethanol on the brain and separate such effects from genetic background and other environmental insults. In the present study the effects of moderate ethanol vapor exposure, during adolescence, on measures of neurogenesis and behavioral measures were evaluated at two different times following ethanol withdrawal, in adulthood. The two groups of Wistar rats were both exposed to intermittent ethanol vapor (14 h on/10h off/day) for 35-36 days from PD 23 to PD 58 (average blood ethanol concentration: 163 mg%). In the first group, after rats were withdrawn from vapor they were subsequently assessed for locomotor activity, conflict behavior in the open field, and behaviors in the forced swim test (FST) and then sacrificed at 72 days of age. The second group of rats were withdrawn from vapor and injected for 5 days with Bromo-deoxy-Uridine (BrdU). Over the next 8 weeks they were also assessed for locomotor activity, conflict behavior in the open field, and behaviors in the FST and then sacrificed at 113/114 days of age. All rats were perfused for histochemical analyses. Ethanol vapor-exposed rats displayed hypoactivity in tests of locomotion and less anxiety-like and/or more "disinhibitory" behavior in the open field conflict. Quantitative analyses of immunoreactivity revealed a significant reduction in measures of neurogenesis, progenitor proliferation, as indexed by doublecortin (DCX), Ki67, and increased markers of cell death as indexed by cleaved caspase-3, and Fluoro-Jade at 72 days, and decreases in DCX, and increases in cleaved caspase-3 at 114 days in the ethanol vapor-exposed rats. Progenitor survival, as assessed by BrdU+, was reduced in the vapor-exposed animals that were sacrificed at 114 days. The reduction seen in DCX labeled in cell counts was significantly correlated with hypoactivity at 24h after withdrawal as well as less anxiety-like and/or more "disinhibitory" behavior in the open field conflict test at 2 and 8 weeks following termination of vapor exposure. These studies demonstrate that behavioral measures of disinhibitory behavior correlated with decreases in neurogenesis are all significantly and persistently impacted by periadolescent ethanol exposure and withdrawal in Wistar rats.
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17
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Abstract
Ethanol's effects on intracellular signaling pathways contribute to acute effects of ethanol as well as to neuroadaptive responses to repeated ethanol exposure. In this chapter we review recent discoveries that demonstrate how ethanol alters signaling pathways involving several receptor tyrosine kinases and intracellular tyrosine and serine-threonine kinases, with consequences for regulation of cell surface receptor function, gene expression, protein translation, neuronal excitability and animal behavior. We also describe recent work that demonstrates a key role for ethanol in regulating the function of scaffolding proteins that organize signaling complexes into functional units. Finally, we review recent exciting studies demonstrating ethanol modulation of DNA and histone modification and the expression of microRNAs, indicating epigenetic mechanisms by which ethanol regulates neuronal gene expression and addictive behaviors.
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Affiliation(s)
- Dorit Ron
- Ernest Gallo Clinic and Research Center, University of California San Francisco, 5858 Horton Street, Suite 200, Emeryville, CA 94608, USA
| | - Robert O. Messing
- Ernest Gallo Clinic and Research Center, University of California San Francisco, 5858 Horton Street, Suite 200, Emeryville, CA 94608, USA
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18
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When a TRP goes bad: transient receptor potential channels in addiction. Life Sci 2012; 92:410-4. [PMID: 22820171 DOI: 10.1016/j.lfs.2012.07.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Revised: 07/04/2012] [Accepted: 07/07/2012] [Indexed: 12/22/2022]
Abstract
Drug addiction is a psychiatric disease state, wherein a drug is impulsively and compulsively self-administered despite negative consequences. This repeated administration results in permanent changes to nervous system physiology and architecture. The molecular pathways affected by addictive drugs are complex and inter-dependent on each other. Recently, various new proteins and protein families have been discovered to play a role in drug abuse. Emerging players in this phenomenon include TRP (Transient Receptor Potential) family channels, which are primarily known to function in sensory systems. Several TRP family channels identified in both vertebrates and invertebrates are involved in psychostimulant-induced plasticity, suggesting their involvement in drug dependence. This review summarizes various observations, both from studies in humans and other organisms, which support a role for these channels in the development of drug-related behaviors.
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Rueda AVL, Teixeira AMA, Yonamine M, Camarini R. Environmental enrichment blocks ethanol-induced locomotor sensitization and decreases BDNF levels in the prefrontal cortex in mice. Addict Biol 2012; 17:736-45. [PMID: 22126132 DOI: 10.1111/j.1369-1600.2011.00408.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The use of addictive drugs can lead to long-term neuroplastic changes in the brain, including behavioral sensitization, a phenomenon related to addiction. Environmental enrichment (EE) is a strategy used to study the effect of environment on the response to several manipulations, including treatment with addictive drugs. Brain-derived neurotrophic factor (BDNF) has been associated with behaviors related to ethanol addiction. The aim of the present study was to evaluate the effects of EE on ethanol-induced behavioral sensitization and BDNF expression. Mice were exposed to EE and then repeatedly treated with a low dose (1.8 g/kg) of ethanol. Another group of mice was first subjected to repeated ethanol treatment according to the behavioral sensitization protocol and then exposed to EE. Environmental enrichment prevented the development of ethanol-induced behavioral sensitization and blocked behavioral sensitization in sensitized mice. Both repeated ethanol and EE decreased BDNF levels in the prefrontal cortex but not in the hippocampus. However, BDNF levels were lower in ethanol-treated mice exposed to EE. These findings suggest that EE can act on the mechanisms implicated in behavioral sensitization, a model for drug-induced neuroplasticity and relapse. Additionally, EE alters BDNF levels, which regulate addiction-related behaviors.
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Affiliation(s)
- André Veloso Lima Rueda
- Departamento de Farmacologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Brazil
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Femenía T, Manzanares J. Increased ethanol intake in prodynorphin knockout mice is associated to changes in opioid receptor function and dopamine transmission. Addict Biol 2012; 17:322-37. [PMID: 21966993 DOI: 10.1111/j.1369-1600.2011.00378.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The purpose of this study was to examine the role of the prodynorphin gene in alcohol sensitivity, preference and vulnerability to alcohol consumption. Handling-induced convulsion (HIC) associated to alcohol, alcohol-induced loss of righting reflex (LORR), hypothermic effects in response to acute ethanol challenge, blood ethanol levels (BELs), conditioned place preference, voluntary ethanol consumption and preference, tyrosine hydroxylase (TH), dopamine transporter (DAT) and proenkephalin (PENK) gene expression, and µ-, δ- and κ-opioid agonist-stimulated [S(35) ]- guanosine 5'-triphosphate-binding autoradiography were studied in prodynorphin knockout (PDYN KO) and wild-type (WT) mice. There were no differences in HIC, LORR or the decrease in body temperature in response to acute ethanol challenge between PDYN KO and WT mice. PDYN KO mice presented higher BEL, higher ethanol-conditioned place preference and more ethanol consumption and preference in a two-bottle choice paradigm than WT mice. These findings were associated with lower TH and higher DAT gene expression in the ventral tegmental area and substantia nigra, and with lower PENK gene expression in the caudate-putamen (CPu), accumbens core (AcbC) and accumbens shell (AcbSh) in PDYN KO. The functional activity of the µ-opioid receptor was lower in the CPu, AcbC, AcbSh and cingulate cortex (Cg) of PDYN KO mice. In contrast, δ- and κ-opioid receptor-binding autoradiographies were increased in the CPu and Cg (δ), and in the CPu, AcbC and Cg (κ) of PDYN KO. These results suggest that deletion of the PDYN gene increased vulnerability for ethanol consumption by altering, at least in part, PENK, TH and DAT gene expression, and µ-, δ- and κ-opioid receptor functional activity in brain areas closely related to ethanol reinforcement.
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Affiliation(s)
- Teresa Femenía
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
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21
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Guo Y, Chen Y, Carreon S, Qiang M. Chronic intermittent ethanol exposure and its removal induce a different miRNA expression pattern in primary cortical neuronal cultures. Alcohol Clin Exp Res 2011; 36:1058-66. [PMID: 22141737 DOI: 10.1111/j.1530-0277.2011.01689.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND Increasing evidence indicates that repeated exposure to and withdrawal from alcohol can result in persistent molecular and cellular adaptations. One molecular adaptation that occurs is the regulation of gene expression, which is thought to lead to the functional alterations that characterize addiction: tolerance, dependence, withdrawal, craving, and relapse. MicroRNAs (miRNAs) have been recently identified as master regulators of gene expression through post-transcriptional regulation. However, the role of miRNAs in the neuroadaptations after alcohol removal has not yet been directly addressed. METHODS We employed a chronic intermittent ethanol (CIE) model in primary cortical neuronal cultures to examine the global extent of differential miRNA expression using a TaqMan real-time PCR miRNA array. RESULTS Sixty-two miRNAs were differentially expressed after 10 days of CIE (CIE10) treatment (n = 42 with false discovery rate [FDR] < 0.05 and fold change > 2) and 5 days post-CIE (P5) treatment (n = 26) compared with untreated control values. Compared to CIE10, ethanol (EtOH) removal experience in P5 induced a distinct expression pattern, including 20 differentially expressed miRNAs, which did not exhibit a significant change at CIE10. The predicted target molecules of EtOH removal-induced miRNAs function mainly in the regulation of gene transcription, but also function in neuron differentiation, embryonic development, protein phosphorylation, and synaptic plasticity. Interestingly, some of the miRNAs differentially expressed 5 days after CIE treatment were found to cluster on chromosomes near CpG islands, suggesting that they share functional similarity by targeting alcohol-related genes. CONCLUSIONS Taken together, these results suggest a potential role of differentially expressed miRNAs in mediating EtOH removal-related phenotypes.
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Affiliation(s)
- Yingqiu Guo
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3900, USA
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22
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Ehlers CL, Criado JR, Wills DN, Liu W, Crews FT. Periadolescent ethanol exposure reduces adult forebrain ChAT+IR neurons: correlation with behavioral pathology. Neuroscience 2011; 199:333-45. [PMID: 22033458 DOI: 10.1016/j.neuroscience.2011.10.011] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 10/07/2011] [Accepted: 10/09/2011] [Indexed: 01/15/2023]
Abstract
Substance abuse typically begins in adolescence; therefore, the impact of alcohol during this critical time in brain development is of particular importance. Epidemiological data indicate that excessive alcohol consumption is prevalent among adolescents and may have lasting neurobehavioral consequences. Loss of cholinergic input to the forebrain has been demonstrated following fetal alcohol exposure and in adults with Wernicke-Korsakoff syndrome. In the present study, immunohistochemistry for choline acetyltransferase (ChAT) was determined to assess forebrain cholinergic neurons (Ch1-4), and behavioral changes following periadolescent alcohol exposure. Wistar rats were exposed to intermittent ethanol vapor (14 h on/10 h off/day) for 35 days from postnatal day (PD) 22 to PD 57 (average blood alcohol concentration (BAC): 163 mg%). Rats were withdrawn from vapor and assessed for locomotor activity, startle response, conflict behavior in the open field, and immobility in the forced swim test, as adults. Rats were then sacrificed at day 71/72 and perfused for histochemical analyses. Ethanol vapor-exposed rats displayed: increased locomotor activity 8 h after the termination of vapor delivery for that 24 h period at day 10 and day 20 of alcohol vapor exposure, significant reductions in the amplitude of their responses to prepulse stimuli during the startle paradigm at 24 h withdrawal, and at 2 weeks following withdrawal, less anxiety-like and/or more "disinhibitory" behavior in the open field conflict, and more immobility in the forced swim test. Quantitative analyses of ChAT immunoreactivity revealed a significant reduction in cell counts in the Ch1-2 and Ch3-4 regions of the basal forebrain in ethanol vapor-exposed rats. This reduction in cell counts was significantly correlated with less anxiety-like and/or more "disinhibitory" behavior in the open field conflict test. These studies demonstrate that behavioral measures of arousal, affective state, disinhibitory behavior, and ChAT+IR, are all significantly impacted by periadolescent ethanol exposure and withdrawal in Wistar rats.
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Affiliation(s)
- C L Ehlers
- Department of Molecular and Integrative Neurosciences, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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Liu K, Steketee JD. Repeated exposure to cocaine alters medial prefrontal cortex dopamine D₂-like receptor modulation of glutamate and dopamine neurotransmission within the mesocorticolimbic system. J Neurochem 2011; 119:332-41. [PMID: 21692802 DOI: 10.1111/j.1471-4159.2011.07362.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Repeated exposure to cocaine progressively increases drug-induced locomotor activity, which is termed behavioral sensitization. Previous studies have demonstrated that sensitization to cocaine is associated with a decrease in dopamine D₂ receptor function in the medial prefrontal cortex. The present report tested the hypothesis that reduced medial prefrontal cortex D₂ receptor function as a result of repeated cocaine exposure results in augmented excitatory transmission to the nucleus accumbens and ventral tegmental area, possibly as a partial result of enhanced inhibition of local dopamine release. Dual probe microdialysis experiments were conducted in male Sprague-Dawley rats 1, 7 or 30 days following the last of four daily injections of saline (1.0 mL/kg) or cocaine (15 mg/kg). Infusion of quinpirole (0.01, 1.0 and 100 μM), a D₂-like receptor agonist, into the medial prefrontal cortex produced a dose-dependent decrease in cortical, nucleus accumbens and ventral tegmental area extracellular glutamate levels in control but not sensitized animals. Quinpirole also reduced basal dopamine levels in the medial prefrontal cortex in sensitized animals following 1 day of withdrawal from cocaine. Following 30 days of withdrawal, quinpirole also reduced dopamine levels in sensitized animals relative to saline controls, but not relative to baseline levels. These findings indicate that the expression of sensitization to cocaine is associated with altered modulation of mesocorticolimbic glutamatergic transmission at the level of the medial prefrontal cortex.
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Affiliation(s)
- Kun Liu
- Department Pharmacology, University of Tennessee Health Science Center, Memphis, Tennessee, USA
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24
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He YY, Xue YX, Wang JS, Fang Q, Liu JF, Xue LF, Lu L. PKMζ maintains drug reward and aversion memory in the basolateral amygdala and extinction memory in the infralimbic cortex. Neuropsychopharmacology 2011; 36:1972-81. [PMID: 21633338 PMCID: PMC3158313 DOI: 10.1038/npp.2011.63] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The intense associative memories that develop between drug-paired contextual cues and rewarding stimuli or the drug withdrawal-associated aversive feeling have been suggested to contribute to the high rate of relapse. Various studies have elucidated the mechanisms underlying the formation and expression of drug-related cue memories, but how this mechanism is maintained is unknown. Protein kinase M ζ (PKMζ) was recently shown to be necessary and sufficient for long-term potentiation maintenance and memory storage. In the present study, we used conditioned place preference (CPP) and aversion (CPA) to examine whether PKMζ maintains both morphine-associated reward memory and morphine withdrawal-associated aversive memory in the basolateral amygdala (BLA). We also investigate the role of PKMζ in the infralimbic cortex in the extinction memory of morphine reward-related cues and morphine withdrawal-related aversive cues. We found that intra-BLA but not central nucleus of the amygdala injection of the selective PKMζ inhibitor ZIP 1 day after CPP and CPA training impaired the expression of CPP and CPA 1 day later, and the effect of ZIP on memory lasted at least 2 weeks. Inhibiting PKMζ activity in the infralimbic cortex, but not prelimbic cortex, disrupted the expression of the extinction memory of CPP and CPA. These results indicate that PKMζ in the BLA is required for the maintenance of associative morphine reward memory and morphine withdrawal-associated aversion memory, and PKMζ in the infralimbic cortex is required for the maintenance of extinction memory of morphine reward-related cues and morphine withdrawal-related aversive cues.
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Affiliation(s)
- Ying-Ying He
- Affiliated Hospital and School of Pharmacy of Guiyang Medical University, Guiyang, China,National Institute on Drug Dependence, Peking University, Beijing, China
| | - Yan-Xue Xue
- National Institute on Drug Dependence, Peking University, Beijing, China
| | - Ji-shi Wang
- Affiliated Hospital and School of Pharmacy of Guiyang Medical University, Guiyang, China,Affiliated Hospital of Guiyang Medical College, Guiyang 550004, China. Tel: +86 851 675 7898; Fax: +86 851 675 7898; E-mail:
| | - Qin Fang
- Affiliated Hospital and School of Pharmacy of Guiyang Medical University, Guiyang, China
| | - Jian-Feng Liu
- National Institute on Drug Dependence, Peking University, Beijing, China
| | - Li-Fen Xue
- National Institute on Drug Dependence, Peking University, Beijing, China
| | - Lin Lu
- National Institute on Drug Dependence, Peking University, Beijing, China,National Institute on Drug Dependence, Peking University, Beijing 100191, China. Tel: +86 108 280 2459, Fax: +86 106 203 2624; E-mail:
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25
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Qiang M, Denny A, Lieu M, Carreon S, Li J. Histone H3K9 modifications are a local chromatin event involved in ethanol-induced neuroadaptation of the NR2B gene. Epigenetics 2011; 6:1095-104. [PMID: 21814037 DOI: 10.4161/epi.6.9.16924] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Expression of the NMDA receptor 2B (NR2B) gene is upregulated following chronic intermittent ethanol (CIE) treatment and withdrawal, which underlies behavioral alterations in addiction. The goal of this study was to characterize the changes of histone modifications induced by CIE treatment and its subsequent removal associated to the upregulation of NR2B gene transcription. To investigate the involvement of histone acetylation in the effect of ethanol on the NR2B gene, we examined the influence of CIE on histone acetylation in the 5' regulatory region of NR2B using a qChIP assay. CIE treatment and its subsequent removal produced a remarkable and selected increase in histone H3K9 acetylation. Interestingly, the majority of the increased H3K9 acetylation occurred after ethanol removal, which was coincident with a decrease in H3K9 methylation in the same time duration. Further examination of the mechanisms of ethanol-induced alterations on the histone modifications revealed that CIE-induced acetylation of H3K9 was not due to the changes in global enzyme activities or the expression of histone acetyltransferases (HATs) and deacetylase (HDACs). Instead, we found a significant downregulation in some histone methyltransferases (HMTs) at both the global level and the local chromatin of the NR2B gene following CIE treatment. Moreover, our experiments also indicated a decrease of G9a, Suv39 h1 and HDAC1-3 in the chromatin of the NR2B gene promoter, which may be responsible for the altered H3K9 modifications. Taken together, the findings suggest a mechanism where the changes in H3K9 modifications in the local chromatin of the NR2B gene underlie alcohol-induced neuroadaptation.
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Affiliation(s)
- Mei Qiang
- Department of Pharmacology; The University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
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26
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Yévenes GE, Moraga-Cid G, Romo X, Aguayo LG. Activated G protein α s subunits increase the ethanol sensitivity of human glycine receptors. J Pharmacol Exp Ther 2011; 339:386-93. [PMID: 21821696 DOI: 10.1124/jpet.111.184408] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
It is well known that ethanol modulates the function of the Cys loop ligand-gated ion channels, which include the inhibitory glycine receptors (GlyRs). Previous studies have consistently shown that transmembrane and extracellular sites are essential for ethanol actions in GlyRs. In addition, recent evidence has shown that the ethanol modulation of GlyRs is also affected by G protein activation through Gβγ subunits. However, more specific roles of G protein α subunits on ethanol actions are unknown. Here, we show that the allosteric effect of ethanol on the human α(1) GlyR is selectively enhanced by the expression of Gα(s) Q-L. For example, constitutively active Gα(s), but not Gα(q) or Gα(i), was able to displace the alcohol sensitivity of GlyRs toward low millimolar concentrations (17 ± 4 versus 48 ± 5% at 100 mM). Experiments under conditions that increased cAMP and protein kinase A (PKA)-mediated signaling, on the contrary, did not produce the same enhancement in sensitivity, suggesting that the Gα(s) Q-L effect was not dependent on cAMP/PKA-dependent signaling. On the other hand, the effect of Gα(s) Q-L was blocked by a Gβγ scavenger (9 ± 3% of control). Furthermore, two mutant receptors previously shown to have impaired interactions with Gβγ were not affected by Gα(s) Q-L, suggesting that Gβγ is needed for enhancing ethanol sensitivity. These results support the conclusion that activated Gα(s) can facilitate the Gβγ interaction with GlyRs in presence of ethanol, independent of increases in cAMP signaling. Thus, these data indicate that the activated form of Gα(s) is able to positively influence the effect of ethanol on a type of inhibitory receptor important for motor control, pain, and respiration.
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Affiliation(s)
- Gonzalo E Yévenes
- Laboratory of Neurophysiology, Department of Physiology, University of Concepción, Concepción, Chile
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Carrara-Nascimento PF, Griffin WC, Pastrello DM, Olive MF, Camarini R. Changes in extracellular levels of glutamate in the nucleus accumbens after ethanol-induced behavioral sensitization in adolescent and adult mice. Alcohol 2011; 45:451-60. [PMID: 21570797 DOI: 10.1016/j.alcohol.2011.01.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Revised: 01/20/2011] [Accepted: 01/24/2011] [Indexed: 12/25/2022]
Abstract
Repeated administration of low doses of ethanol gradually increases locomotor responses to ethanol in adult Swiss mice. This phenomenon is known as behavioral sensitization. However, we have shown that adolescent Swiss mice show either behavioral tolerance or no sensitization after repeated ethanol injections. Although the mesolimbic dopamine system has been extensively implicated in behavioral sensitization, several studies have demonstrated an important role of glutamatergic transmission in this phenomenon. In addition, relatively few studies have examined the role of developmental factors in behavioral sensitization to ethanol. To examine the relationship between age differences in behavioral sensitization to ethanol and the neurochemical adaptations related to glutamate within nucleus accumbens (NAc), in vivo microdialysis was conducted in adolescent and adult Swiss mice treated with ethanol (1.8 g/kg) or saline for 15 days and subsequently challenged with an acute dose (1.8 g/kg) of ethanol 6 days later. Consistent with previous findings, only adult mice demonstrated evidence of behavioral sensitization. However, ethanol-treated adolescent mice demonstrated a 196.1 ± 40.0% peak increase in extracellular levels of glutamate in the NAc after ethanol challenge in comparison with the basal values, whereas ethanol-treated adult mice demonstrated a 52.2 ± 6.2% reduction in extracellular levels of glutamate in the NAc after ethanol challenge. These observations suggest an age-dependent inverse relationship between behavioral and glutamatergic responses to repeated ethanol exposure.
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Cleva RM, Gass JT, Widholm JJ, Olive MF. Glutamatergic targets for enhancing extinction learning in drug addiction. Curr Neuropharmacol 2011; 8:394-408. [PMID: 21629446 PMCID: PMC3080595 DOI: 10.2174/157015910793358169] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2009] [Revised: 05/11/2010] [Accepted: 05/26/2010] [Indexed: 12/29/2022] Open
Abstract
The persistence of the motivational salience of drug-related environmental cues and contexts is one of the most problematic obstacles to successful treatment of drug addiction. Behavioral approaches to extinguishing the salience of drug-associated cues, such as cue exposure therapy, have generally produced disappointing results which have been attributed to, among other things, the context specificity of extinction and inadequate consolidation of extinction learning. Extinction of any behavior or conditioned response is a process of new and active learning, and increasing evidence suggests that glutamatergic neurotransmission, a key component of the neural plasticity that underlies normal learning and memory, is also involved in extinction learning. This review will summarize findings from both animal and human studies that suggest that pharmacological enhancement of glutamatergic neurotransmission facilitates extinction learning in the context of drug addiction. Pharmacological agents that have shown potential efficacy include NMDA partial agonists, mGluR5 receptor positive allosteric modulators, inhibitors of the GlyT1 glycine transporter, AMPA receptor potentiators, and activators of the cystine-glutamate exchanger. These classes of cognition-enhancing compounds could potentially serve as novel pharmacological adjuncts to cue exposure therapy to increase success rates in attenuating cue-induced drug craving and relapse.
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Affiliation(s)
- R M Cleva
- Center for Drug and Alcohol Programs, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, South Carolina, 29425, USA
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Kaushal N, Robson MJ, Vinnakota H, Narayanan S, Avery BA, McCurdy CR, Matsumoto RR. Synthesis and pharmacological evaluation of 6-acetyl-3-(4-(4-(4-fluorophenyl)piperazin-1-yl)butyl)benzo[d]oxazol-2(3H)-one (SN79), a cocaine antagonist, in rodents. AAPS JOURNAL 2011; 13:336-46. [PMID: 21494909 DOI: 10.1208/s12248-011-9274-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Accepted: 04/04/2011] [Indexed: 01/13/2023]
Abstract
Cocaine interacts with monoamine transporters and sigma (σ) receptors, providing logical targets for medication development. In the present study, in vitro and in vivo pharmacological studies were conducted to characterize SN79, a novel compound which was evaluated for cocaine antagonist actions. Radioligand binding studies showed that SN79 had a nanomolar affinity for σ receptors and a notable affinity for 5-HT(2) receptors, and monoamine transporters. It did not inhibit major cytochrome P450 enzymes, including CYP1A2, CYP2A6, CYP2C19, CYP2C9*1, CYP2D6, and CYP3A4, suggesting a low propensity for potential drug-drug interactions. Oral administration of SN79 reached peak in vivo concentrations after 1.5 h and exhibited a half-life of just over 7.5 h in male, Sprague-Dawley rats. Behavioral studies conducted in male, Swiss Webster mice, intraperitoneal or oral dosing with SN79 prior to a convulsive or locomotor stimulant dose of cocaine led to a significant attenuation of cocaine-induced convulsions and locomotor activity. However, SN79 produced sedation and motor incoordination on its own at higher doses, to which animals became tolerant with repeated administration. SN79 also significantly attenuated the development and expression of the sensitized response to repeated cocaine exposures. The ability of SN79 to significantly attenuate the acute and subchronic effects of cocaine provides a promising compound lead to the development of an effective pharmacotherapy against cocaine.
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Affiliation(s)
- Nidhi Kaushal
- Basic Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, 26506, USA
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Prior chronic cocaine exposure in mice induces persistent alterations in cognitive function. Behav Pharmacol 2010; 20:695-704. [PMID: 19901826 DOI: 10.1097/fbp.0b013e328333a2bb] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Chronic cocaine use has been proposed to induce long-lasting alterations in cognitive functions dependent on the prefrontal cortex, and these alterations may contribute to the development of addiction. However, the underlying cellular mechanisms remain largely unknown, in part because of the lack of suitable animal models of cocaine-induced cognitive dysfunction that are amenable to molecular manipulations. Here, we characterized the effects of repeated cocaine administration on multiple aspects of cognitive function in C57BL/6 mice. Mice received 14 daily injections of either cocaine or saline, followed by a drug-free period of 2 weeks. They were then assessed for (i) cognitive flexibility in an instrumental reversal learning task; (ii) attentional function and response inhibition in a three-choice serial reaction time task; and (iii) working memory in a delayed matching-to-position task. Prior chronic exposure to cocaine resulted in impairments in reversal learning and working memory. Although there were no effects on attentional function or response inhibition, a shift in the pattern of errors committed was observed. These results indicate that prior chronic cocaine exposure in mice induces long-lasting alterations in cognitive functions associated with the prefrontal cortex.
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31
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Sun J, Zhao Z. Functional features, biological pathways, and protein interaction networks of addiction-related genes. Chem Biodivers 2010; 7:1153-62. [PMID: 20491072 DOI: 10.1002/cbdv.200900319] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Addictions are chronic and common brain disorders affected by many genetic, environmental, and behavioral factors. Recent genome-wide linkage and association studies have revealed several promising genomic regions and multiple genes relating to addictions. To explore the underlying biological processes in the development of addictions, we used 62 genes recently reviewed by Li and Burmeister (2009) as representative addiction-related genes, and then we investigated their features in gene function, pathways, and protein interaction networks. We performed enrichment tests of their Gene Ontology (GO) annotations and of their pathways in the Ingenuity Pathways Analysis (IPA) system. The tests revealed that these addiction-related genes were highly enriched in neurodevelopment-related processes. Interestingly, we found circadian rhythm signaling in one of the enriched pathways. Moreover, these addiction-related genes tended to have higher connectivity and shorter characteristic shortest-path distances compared to control genes in the protein-protein interaction (PPI) network. This investigation is the first of such kind in addiction studies, and it is useful for further addiction candidate-gene prioritization and verification, thus helping us to better understand molecular mechanisms of addictions.
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Affiliation(s)
- Jingchun Sun
- Department of Biomedical Informatics, Vanderbilt University Medical Center, 2525 West End Avenue, Suite 600, Nashville, TN 37203, USA
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32
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Abstract
Drug addiction is marked by continued drug-seeking behavior despite deleterious consequences and a heightened propensity to relapse not withstanding long, drug-free periods. The enduring nature of addiction has been hypothesized to arise from perturbations in intracellular signaling, gene expression, and brain circuitry induced by substance abuse. Ameliorating some of these aberrations should abate behavioral and neurochemical markers associated with an 'addiction phenotype'. This review summarizes data showing that protein expression and signaling through the nonreceptor activator of G-protein signaling 3 (AGS3) are altered by commonly abused substances in rat and in in-vitro addiction models. AGS3 structure and function are unrelated to the more broadly studied regulator of G-protein signaling family. Thus, the unique role of AGS3 is the focus of this review. Intriguingly, AGS3 protein changes persist into drug abstinence. Accordingly, studies probing the role of AGS3 in the neurochemistry of drug-seeking behavior and relapse are studied in detail. To illuminate this study, AGS3 structure, cellular localization, and function are covered so that an idealized AGS3-targeted pharmacotherapy can be proposed.
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Affiliation(s)
- Michael Scott Bowers
- Department of Psychiatry, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA.
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Pian JP, Criado JR, Milner R, Ehlers CL. N-methyl-D-aspartate receptor subunit expression in adult and adolescent brain following chronic ethanol exposure. Neuroscience 2010; 170:645-54. [PMID: 20603193 DOI: 10.1016/j.neuroscience.2010.06.065] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Revised: 06/16/2010] [Accepted: 06/25/2010] [Indexed: 11/17/2022]
Abstract
Substantial evidence suggests that glutamatergic neurotransmission is a critical mediator of the experience-dependent synaptic plasticity that may underlie alcohol dependence. Substance abuse typically begins in adolescence; therefore, the impact of alcohol on glutamatergic systems during this critical time in brain development is of particular importance. The N-methyl-d-aspartate receptor (NMDAR) is involved in developmental mechanisms underlying neuronal differentiation and synaptogenesis and as such may be a target system for alcohol effects during adolescence. In the present study quantitative biochemical determinations were made of the relative abundance of different protein expressions of NMDAR subunits in adolescents and adults after 2 weeks of ethanol vapor exposure, and 24 h and 2 weeks following withdrawal. After 2 weeks of ethanol vapor exposure N-methyl-d-aspartate receptor NR1 subunit (NR1), N-methyl-d-aspartate receptor NR2A subunit (NR2A), and N-methyl-d-aspartate receptor NR2B subunit (NR2B) subunit expression was found to be increased in hippocampus of the adults. In contrast, 2 weeks of ethanol exposure resulted in no significant changes in NR1 and NR2B subunits and a reduction NR2A subunit expression in hippocampus in adolescents. Twenty-four h and 2 weeks following withdrawal from ethanol vapor NR1 and NR2A subunit expression in hippocampus was decreased in adolescents, whereas in adults it had returned to control levels. In frontal cortex, 2 weeks of chronic ethanol exposure produced decreases in NR1 subunit expression in both adults and adolescents but also produced decreases in NR2A and NR2B subunit expression in adults that returned or exceeded control levels by 2 weeks following withdrawal from ethanol vapor. These results demonstrate that NMDAR subunit composition can be modulated differentially between adolescents and adults by chronic ethanol exposure and withdrawal. These developmental differences in NMDAR subunits composition may also be associated with the enhanced vulnerability of the adolescent brain to ethanol dependence.
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Affiliation(s)
- J P Pian
- Department of Molecular and Integrative Neurosciences, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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Molecular targets and mechanisms for ethanol action in glycine receptors. Pharmacol Ther 2010; 127:53-65. [PMID: 20399807 DOI: 10.1016/j.pharmthera.2010.03.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Accepted: 03/23/2010] [Indexed: 11/23/2022]
Abstract
Glycine receptors (GlyRs) are recognized as the primary mediators of neuronal inhibition in the spinal cord, brain stem and higher brain regions known to be sensitive to ethanol. Building evidence supports the notion that ethanol acting on GlyRs causes at least a subset of its behavioral effects and may be involved in modulating ethanol intake. For over two decades, GlyRs have been studied at the molecular level as targets for ethanol action. Despite the advances in understanding the effects of ethanol in vivo and in vitro, the precise molecular sites and mechanisms of action for ethanol in ligand-gated ion channels in general, and in GlyRs specifically, are just now starting to become understood. The present review focuses on advances in our knowledge produced by using molecular biology, pressure antagonism, electrophysiology and molecular modeling strategies over the last two decades to probe, identify and model the initial molecular sites and mechanisms of ethanol action in GlyRs. The molecular targets on the GlyR are covered on a global perspective, which includes the intracellular, transmembrane and extracellular domains. The latter has received increasing attention in recent years. Recent molecular models of the sites of ethanol action in GlyRs and their implications to our understanding of possible mechanism of ethanol action and novel targets for drug development in GlyRs are discussed.
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35
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Early life protein restriction alters dopamine circuitry. Neuroscience 2010; 168:359-70. [PMID: 20394806 DOI: 10.1016/j.neuroscience.2010.04.010] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Revised: 03/23/2010] [Accepted: 04/05/2010] [Indexed: 11/22/2022]
Abstract
Adverse prenatal environment, such as intrauterine growth retardation (IUGR), increases the risk for negative neurobehavioral outcomes. IUGR, affecting approximately 10% of all US infants, is a known risk factor for attention deficit hyperactivity disorder (ADHD), schizophrenia spectrum disorders and addiction. Mouse dams were fed a protein deficient (8.5% protein) or isocaloric control (18% protein) diet through pregnancy and lactation (a well validated rodent model of IUGR). Dopamine-related gene expression, dopamine content and behavior were examined in adult offspring. IUGR offspring have six to eightfold over-expression of dopamine (DA)-related genes (tyrosine hydroxylase (TH) and dopamine transporter) in brain regions related to reward processing (ventral tegmental area (VTA), nucleus accumbens, prefrontal cortex (PFC)) and homeostatic control (hypothalamus), as well as increased number of TH-ir neurons in the VTA and increased dopamine in the PFC. Cyclin-dependent kinase inhibitor 1C (Cdkn1c) is critical for dopaminergic neuron development. Methylation of the promoter region of Cdkn1c was decreased by half and there was a resultant two to sevenfold increase in Cdkn1c mRNA expression across brain regions. IUGR animals demonstrated alterations in dopamine-dependent behaviors, including altered reward-processing, hyperactivity and exaggerated locomotor response to cocaine. These data describe significant dopamine-related molecular and behavioral abnormalities in a mouse model of IUGR. This animal model, with both face validity (behavior) and construct validity (link to IUGR and dopamine dysfunction) may prove useful in identifying underlying mechanisms linking IUGR and adverse neurobehavioral outcomes such as ADHD.
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36
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Qiang M, Denny A, Chen J, Ticku MK, Yan B, Henderson G. The site specific demethylation in the 5'-regulatory area of NMDA receptor 2B subunit gene associated with CIE-induced up-regulation of transcription. PLoS One 2010; 5:e8798. [PMID: 20098704 PMCID: PMC2808353 DOI: 10.1371/journal.pone.0008798] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Accepted: 12/18/2009] [Indexed: 12/17/2022] Open
Abstract
Background The NMDA receptor represents a particularly important site of ethanol action in the CNS. We recently reported that NMDA receptor 2B (NR2B) gene expression was persistently up-regulated following chronic intermittent ethanol (CIE) treatment. Increasing evidence that epigenetic mechanisms are involved in dynamic and long-lasting regulation of gene expression in multiple neuroadaptive processes prompted us to investigate the role of DNA methylation in mediating CIE-induced up-regulation of NR2B gene transcription. To dissect the changes of DNA methylation in the NR2B gene, we have screened a large number of CpG sites within its 5′-regulatory area following CIE treatment. Methods Primary cortical cultured neurons were subjected to ethanol treatment in a CIE paradigm. Bisulfite conversion followed by pyrosequencing was used for quantitative measurement and analysis of CpG methylation status within the 5′-regulatory area of the NR2B gene; chromatin immunoprecipitation (ChIP) assay was used to examine DNA levels associated with methylation and transcription factor binding. Electrophoretic mobility shift assay (EMSA) and in vitro DNA methylation assays were performed to determine the direct impact of DNA methylation on the interaction between DNA and transcription factor and promoter activity. Results Analysis of individual CpG methylation sites within the NR2B 5′regulatory area revealed three regions with clusters of site-specific CpG demethylation following CIE treatment and withdrawal. This was confirmed by ChIP showing similar decreases of methylated DNA in the same regions. The CIE-induced demethylation is characterized by being located near certain transcription factor binding sequences, AP-1 and CRE, and occurred during treatment as well as after ethanol withdrawal. Furthermore, the increase in vitro of methylated DNA decreased transcription factor binding activity and promoter activity. An additional ChIP assay indicated that the CIE-induced DNA demethylation is accompanied by increased occupation by transcription factors. Conclusions These results suggest an important role of DNA demethylation in mediating CIE-induced NR2B gene up-regulation, thus implicating a novel molecular site of alcohol action.
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Affiliation(s)
- Mei Qiang
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America.
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37
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Ethanol action on dopaminergic neurons in the ventral tegmental area: interaction with intrinsic ion channels and neurotransmitter inputs. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2010; 91:235-88. [PMID: 20813245 DOI: 10.1016/s0074-7742(10)91008-8] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The dopaminergic system originating in the midbrain ventral tegmental area (VTA) has been extensively studied over the past decades as a critical neural substrate involved in the development of alcoholism and addiction to other drugs of abuse. Accumulating evidence indicates that ethanol modulates the functional output of this system by directly affecting the firing activity of VTA dopamine neurons, whereas withdrawal from chronic ethanol exposure leads to a reduction in the functional output of these neurons. This chapter will provide an update on the mechanistic investigations of the acute ethanol action on dopamine neuron activity and the neuroadaptations/plasticities in the VTA produced by previous ethanol experience.
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Moonat S, Starkman BG, Sakharkar A, Pandey SC. Neuroscience of alcoholism: molecular and cellular mechanisms. Cell Mol Life Sci 2010; 67:73-88. [PMID: 19756388 PMCID: PMC3747955 DOI: 10.1007/s00018-009-0135-y] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 07/28/2009] [Accepted: 08/13/2009] [Indexed: 01/21/2023]
Abstract
Alcohol use and abuse appear to be related to neuroadaptive changes at functional, neurochemical, and structural levels. Acute and chronic ethanol exposure have been shown to modulate function of the activity-dependent gene transcription factor, cAMP-responsive element binding (CREB) protein in the brain, which may be associated with the development of alcoholism. Study of the downstream effectors of CREB have identified several important CREB-related genes, such as neuropeptide Y, brain-derived neurotrophic factor, activity-regulated cytoskeleton-associated protein, and corticotrophin-releasing factor, that may play a crucial role in the behavioral effects of ethanol and molecular changes in the specific neurocircuitry that underlie both alcohol addiction and a genetic predisposition to alcoholism. Brain chromatin remodeling due to histone covalent modifications may also be involved in mediating the behavioral effects and neuroadaptive changes that occur during ethanol exposure. This review outlines progressive neuroscience research into molecular and epigenetic mechanisms of alcoholism.
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Affiliation(s)
- Sachin Moonat
- Department of Psychiatry, University of Illinois at Chicago, Chicago, IL USA
- Jesse Brown VA Medical Center, Chicago, IL USA
| | - Bela G. Starkman
- Department of Psychiatry, University of Illinois at Chicago, Chicago, IL USA
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL USA
- Jesse Brown VA Medical Center, Chicago, IL USA
| | - Amul Sakharkar
- Department of Psychiatry, University of Illinois at Chicago, Chicago, IL USA
- Jesse Brown VA Medical Center, Chicago, IL USA
| | - Subhash C. Pandey
- Department of Psychiatry, University of Illinois at Chicago, Chicago, IL USA
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL USA
- Jesse Brown VA Medical Center, Chicago, IL USA
- Department of Psychiatry, University of Illinois at Chicago and Jesse Brown VA Medical Center, 820 S. Damen Avenue (M/C 151), Chicago, IL 60612 USA
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Tang A, Wanchoo SJ, Swann AC, Dafny N. Psychostimulant treatment for ADHD is modulated by prefrontal cortex manipulation. Brain Res Bull 2009; 80:353-8. [PMID: 19729055 DOI: 10.1016/j.brainresbull.2009.08.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Accepted: 08/26/2009] [Indexed: 01/08/2023]
Abstract
The psychostimulant amphetamine (Amph) is widely used treatments for attention-deficit hyperactivity disorder (ADHD). Chronic intermittent exposure to psychostimulants induces behavioral sensitization. The objective of this study was to investigate the role of prefrontal cortex (PFC) in the acute and chronic effect of Amph using the open-field assay. Male Sprague-Dawley rats were assigned randomly to three groups, (1) an intact control group (2) a PFC sham-operated group, and (3) a PFC lesion group. All the three groups showed increases in locomotor activity after acute amphetamine injection (P<0.05), and activity levels were especially augmented in PFC lesion group. Following chronic amphetamine, the control group and sham-operated group exhibited behavioral sensitization (P<0.05). However, the PFC lesion group failed to exhibit behavioral sensitization and the pattern of locomotion was altered, which indicated that the nature of behavioral sensitization was changed. The results suggest that PFC lesion enhance the acute effects of amphetamine on locomotor activity and is required for development of behavior sensitization.
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Affiliation(s)
- A Tang
- Department of Neurobiology, University of Texas Medical School at Houston, Houston, TX, United States
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40
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Strain specific synaptic modifications on ventral tegmental area dopamine neurons after ethanol exposure. Biol Psychiatry 2009; 65:646-53. [PMID: 19118821 PMCID: PMC3040034 DOI: 10.1016/j.biopsych.2008.10.042] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2007] [Revised: 10/29/2008] [Accepted: 10/30/2008] [Indexed: 11/20/2022]
Abstract
BACKGROUND Genetic factors and previous alcohol experience influence alcohol consumption in both humans and rodents. Specifically, a prior experience with ethanol increases ethanol intake in both ethanol-preferring C57BL/6 (C57) and ethanol non-preferring DBA/2 (DBA) mice. Whereas the ventral tegmental area (VTA) importantly regulates dopamine levels and ethanol intake, it is unknown whether ethanol experience differentially alters synaptic properties of VTA dopamine neurons in ethanol-preferring and non-preferring mice. METHODS The properties of excitatory and inhibitory inputs and the ability to elicit long-term potentiation (LTP) were assessed with whole-cell patch-clamp recordings in VTA dopamine neurons from C57 and DBA mice 24 hours after a single ethanol (2 g/kg, IP) or equivalent saline injection. RESULTS Ethanol exposure increased gamma-aminobutyric acid (GABA) release onto VTA dopamine neurons in DBA mice, as previously observed in C57 mice. However, a single ethanol exposure reduced alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor (AMPAR) and N-methyl-D-aspartate receptor (NMDAR) function and LTP in VTA dopamine neurons from DBA but not C57 mice. CONCLUSIONS A single ethanol exposure selectively reduced glutamate receptor function in VTA dopamine neurons from the ethanol non-preferring DBA strain but enhanced GABA signaling in both C57 and DBA strains. These results support the notion that VTA dopamine neurons are a central target of ethanol-induced neural plasticity, which could contribute to ethanol consumption. Furthermore, these findings highlight the possible need for specialized therapeutic interventions for alcoholism based on individual intrinsic differences.
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41
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Spanagel R. Alcoholism: A Systems Approach From Molecular Physiology to Addictive Behavior. Physiol Rev 2009; 89:649-705. [DOI: 10.1152/physrev.00013.2008] [Citation(s) in RCA: 491] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Alcohol consumption is an integral part of daily life in many societies. The benefits associated with the production, sale, and use of alcoholic beverages come at an enormous cost to these societies. The World Health Organization ranks alcohol as one of the primary causes of the global burden of disease in industrialized countries. Alcohol-related diseases, especially alcoholism, are the result of cumulative responses to alcohol exposure, the genetic make-up of an individual, and the environmental perturbations over time. This complex gene × environment interaction, which has to be seen in a life-span perspective, leads to a large heterogeneity among alcohol-dependent patients, in terms of both the symptom dimensions and the severity of this disorder. Therefore, a reductionistic approach is not very practical if a better understanding of the pathological processes leading to an addictive behavior is to be achieved. Instead, a systems-oriented perspective in which the interactions and dynamics of all endogenous and environmental factors involved are centrally integrated, will lead to further progress in alcohol research. This review adheres to a systems biology perspective such that the interaction of alcohol with primary and secondary targets within the brain is described in relation to the behavioral consequences. As a result of the interaction of alcohol with these targets, alterations in gene expression and synaptic plasticity take place that lead to long-lasting alteration in neuronal network activity. As a subsequent consequence, alcohol-seeking responses ensue that can finally lead via complex environmental interactions to an addictive behavior.
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42
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Unraveling the molecular mechanisms of alcohol dependence. Trends Genet 2009; 25:49-55. [DOI: 10.1016/j.tig.2008.10.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2007] [Revised: 10/10/2008] [Accepted: 10/13/2008] [Indexed: 12/11/2022]
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A selective G betagamma-linked intracellular mechanism for modulation of a ligand-gated ion channel by ethanol. Proc Natl Acad Sci U S A 2008; 105:20523-8. [PMID: 19074265 DOI: 10.1073/pnas.0806257105] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The current understanding about ethanol effects on the ligand-gated ion channel (LGIC) superfamily has been restricted to identify potential binding sites within transmembrane (TM) domains in the Cys-loop family. Here, we demonstrate a key role of the TM3-4 intracellular loop and G betagamma signaling for potentiation of glycine receptors (GlyRs) by ethanol. We discovered 2 motifs within the large intracellular loop of the GlyR alpha(1) subunit that are critical for the actions of pharmacological concentrations of ethanol. Significantly, the sites were ethanol-specific because they did not alter the sensitivity to general anesthetics, neurosteroids, or longer n-alcohols. Furthermore, G betagamma scavengers selectively attenuated the ethanol effects on recombinant and native neuronal GlyRs. These results show a selective mechanism for low-ethanol concentration effects on the GlyR and provide a mechanism on ethanol pharmacology, which may be applicable to other LGIC members. Moreover, these data provide an opportunity to develop new genetically modified animal models and novel drugs to treat alcohol-related medical concerns.
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Kelly MA, Low MJ, Rubinstein M, Phillips TJ. Role of dopamine D1-like receptors in methamphetamine locomotor responses of D2 receptor knockout mice. GENES BRAIN AND BEHAVIOR 2008; 7:568-77. [PMID: 18363855 DOI: 10.1111/j.1601-183x.2008.00392.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Behavioral sensitization to psychostimulants manifests as an increased locomotor response with repeated administration. Dopamine systems are accepted to play a fundamental role in sensitization, but the role of specific dopamine receptor subtypes has not been completely defined. This study used the combination of dopamine D2 receptor-deficient mice and a D1-like antagonist to examine dopamine D1 and D2 receptor involvement in acute and sensitized locomotor responses to methamphetamine. Absence of the dopamine D2 receptor resulted in attenuation of the acute stimulant effects of methamphetamine. Mutant and wild-type mice exhibited sensitization that lasted longer within the time period of the challenge test in the mutant animals. Pretreatment with the D1-like receptor antagonist SCH 23390 produced more potent reductions in the acute and sensitized locomotor responses to methamphetamine in D2 receptor-deficient mice than in wild-type mice; however, the expression of locomotor sensitization when challenged with methamphetamine alone was equivalently attenuated by previous treatment with SCH 23390. These data suggest that dopamine D2 receptors play a key role in the acute stimulant and sensitizing effects of methamphetamine and act in concert with D1-like receptors to influence the acquisition of methamphetamine-induced behavioral sensitization, traits that may influence continued methamphetamine use.
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Affiliation(s)
- M A Kelly
- Vollum Institute, Oregon Health & Science University, Portland, OR, USA
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Nucleus accumbens AGS3 expression drives ethanol seeking through G betagamma. Proc Natl Acad Sci U S A 2008; 105:12533-8. [PMID: 18719114 DOI: 10.1073/pnas.0706999105] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Approximately 90% of alcoholics relapse within 4 years, in part because of an enhanced motivation to seek alcohol (EtOH). A novel G protein modulator (Gpsm1/AGS3) was up-regulated in the rat nucleus accumbens core (NAcore) but not in other limbic nuclei during abstinence from operant EtOH self-administration. Furthermore, NAcore AGS3 knockdown reduced EtOH seeking to pre-abstinence levels in a novel rat model of compulsive, human EtOH seeking. AGS3 can both inhibit G protein G i alpha-mediated signaling and stimulate G betagamma-mediated signaling. Accordingly, sequestration of G betagamma, but not G i alpha knockdown, significantly reduced EtOH seeking to pre-abstinence levels. Thus, AGS3 and G betagamma are hypothesized to gate the uncontrolled motivation to seek EtOH during abstinence. AGS3 up-regulation during abstinence may be a key determinant of the transition from social consumption to compulsion-like seeking during relapse.
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Schroeder JP, Spanos M, Stevenson JR, Besheer J, Salling M, Hodge CW. Cue-induced reinstatement of alcohol-seeking behavior is associated with increased ERK1/2 phosphorylation in specific limbic brain regions: blockade by the mGluR5 antagonist MPEP. Neuropharmacology 2008; 55:546-54. [PMID: 18619984 DOI: 10.1016/j.neuropharm.2008.06.057] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 06/24/2008] [Accepted: 06/25/2008] [Indexed: 01/15/2023]
Abstract
Relapse to alcohol use after periods of abstinence is a hallmark behavioral pathology of alcoholism and a major clinical problem. Emerging evidence indicates that metabotropic glutamate receptor 5 (mGluR5) antagonists attenuate relapse to alcohol-seeking behavior but the molecular mechanisms of this potential therapeutic effect remain unexplored. The extracellular signal-regulated kinase (ERK1/2) pathway is downstream of mGluR5 and has been implicated in addiction. We sought to determine if cue-induced reinstatement of alcohol-seeking behavior, and its reduction by an mGluR5 antagonist, is associated with changes in ERK1/2 activation in reward-related limbic brain regions. Selectively-bred alcohol-preferring (P) rats were trained to lever press on a concurrent schedule of alcohol (15% v/v) vs. water reinforcement. Following 9 days of extinction, rats were given an additional extinction trial or injected with the mGluR5 antagonist MPEP (0, 1, 3, or 10mg/kg) and tested for cue-induced reinstatement. Brains were removed 90-min later from the rats in the extinction and MPEP (0 or 10mg/kg) conditions for analysis of p-ERK1/2, total ERK1/2, and p-ERK5 immunoreactivity (IR). Cue-induced reinstatement of alcohol-seeking behavior was associated with a three to five-fold increase in p-ERK1/2 IR in the basolateral amygdala and nucleus accumbens shell. MPEP administration blocked both the relapse-like behavior and increase in p-ERK1/2 IR. p-ERK1/2 IR in the central amygdala and NAcb core was dissociated with the relapse-like behavior and the pharmacological effect of mGluR5 blockade. No changes in total ERK or p-ERK5 were observed. These results suggest that exposure to cues previously associated with alcohol self-administration is sufficient to produce concomitant increases in relapse-like behavior and ERK1/2 activation in specific limbic brain regions. Pharmacological compounds, such as mGluR5 antagonists, that reduce cue-induced ERK1/2 activation may be useful for treatment of relapse in alcoholics that is triggered by exposure to environmental events.
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Affiliation(s)
- Jason P Schroeder
- Department of Psychiatry, Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Thurston-Bowles Building; CB #7178, Chapel Hill, NC 27599, USA
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López-Moreno JA, González-Cuevas G, Moreno G, Navarro M. The pharmacology of the endocannabinoid system: functional and structural interactions with other neurotransmitter systems and their repercussions in behavioral addiction. Addict Biol 2008; 13:160-87. [PMID: 18422831 DOI: 10.1111/j.1369-1600.2008.00105.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Addiction is a chronic, recurring and complex disorder. It is characterized by anomalous behaviors that are linked to permanent or long-lasting neurobiological alterations. Furthermore, the endocannabinoid system has a crucial role in mediating neurotransmitter release as one of the main neuromodulators of the mammalian central nervous system. The purpose of the present review is to instruct readers about the functional and structural interactions between the endocannabinoid system and the main neurotransmitter systems of the central nervous system in the context of drug addiction. With this aim, we have systematically reviewed the main findings of most of the existing literature that explores cross-talk in the five brain areas that are most traditionally implicated in addiction: amygdala, prefrontal cortex, nucleus accumbens, hippocampus and ventral tegmental area (VTA). The neurotransmission systems influenced by the pharmacology of the endocannabinoid system in these brain areas, which are reviewed here, are gamma-aminobutyric acid (GABA), glutamate, the main biogenic amines (dopamine, noradrenaline and serotonin), acetylcholine and opioids. We show that all of these neurotransmitter systems can be modulated differentially in each brain area by the activation or deactivation of cannabinoid CB1 brain receptors. Specifically, most of the studies relate to the hippocampus and nucleus accumbens. Moreover, the neurotransmitter with the fewest number of related studies is acetylcholine (excepting in the hippocampus), whereas there is a large number that evaluates GABA, glutamate and dopamine. Finally, we propose a possible interpretation of the role of the endocannabinoid system in the phenomenon of addiction.
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Affiliation(s)
- José Antonio López-Moreno
- Department of Psychobiology, Faculty of Psychology, Campus de Somosaguas, Complutense University of Madrid, Spain.
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He DY, Ron D. Glial cell line-derived neurotrophic factor reverses ethanol-mediated increases in tyrosine hydroxylase immunoreactivity via altering the activity of heat shock protein 90. J Biol Chem 2008; 283:12811-8. [PMID: 18343820 PMCID: PMC2442340 DOI: 10.1074/jbc.m706216200] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Revised: 02/01/2008] [Indexed: 12/25/2022] Open
Abstract
We previously found that glial cell line-derived neurotrophic factor (GDNF) in the midbrain ventral tegmental area (VTA) negatively regulates alcohol drinking (He, D. Y., McGough, N. N., Ravindranathan, A., Jeanblanc, J., Logrip, M. L., Phamluong, K., Janak, P. H., and Ron, D. (2005) J. Neurosci. 25, 619-628). Several studies suggest a role for GDNF in the regulation of tyrosine hydroxylase (TH) levels in the midbrain (Georgievska, B., Kirik, D., and Bjorklund, A. (2004) J. Neurosci. 24, 6437-6445). Up-regulation of TH levels has been reported as a hallmark of biochemical adaptations to in vivo chronic exposure to drugs of abuse, including ethanol (Ortiz, J., Fitzgerald, L. W., Charlton, M., Lane, S., Trevisan, L., Guitart, X., Shoemaker, W., Duman, R. S., and Nestler, E. J. (1995) Synapse 21, 289-298). We hypothesized that GDNF plays an important role in regulating prolonged ethanol-mediated increases in TH protein levels. Using the SH-SY5Y dopaminergic-like cell line, we found that the increase in TH levels in the presence of ethanol required the activation of the cAMP/PKA pathway and was reversed by GDNF. Ethanol treatment did not alter the mRNA level or protein translation of TH, but enhanced the stability of the protein that was decreased by GDNF. Interestingly, we observed that ethanol treatment resulted in an increase in TH association with the chaperone heat shock protein (HSP90) that was mediated by the cAMP/PKA pathway and inhibited by GDNF. Taken together, these data suggest that prolonged ethanol exposure leads to increased association of TH and HSP90 via the cAMP/PKA pathway, resulting in the stabilization and subsequent accumulation of TH. GDNF reverses this ethanol-mediated adaptation by inhibiting the interaction of TH with HSP90.
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Affiliation(s)
- Dao-Yao He
- Ernest Gallo Research Center, University of California at San Francisco, Emeryville, California 94608, USA
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Lee MJ, Swann AC, Dafny N. Methylphenidate sensitization is prevented by prefrontal cortex lesion. Brain Res Bull 2008; 76:131-40. [DOI: 10.1016/j.brainresbull.2007.12.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2007] [Revised: 12/04/2007] [Accepted: 12/07/2007] [Indexed: 02/05/2023]
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Boehm SL, Goldfarb KJ, Serio KM, Moore EM, Linsenbardt DN. Does context influence the duration of locomotor sensitization to ethanol in female DBA/2J mice? Psychopharmacology (Berl) 2008; 197:191-201. [PMID: 18049811 PMCID: PMC2279101 DOI: 10.1007/s00213-007-1022-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2006] [Accepted: 11/13/2007] [Indexed: 11/29/2022]
Abstract
RATIONALE Repeated exposure to ethanol produces a progressive increase in locomotor sensitivity, referred to as locomotor sensitization. Locomotor sensitization may persist for some time after termination of repeated drug exposure, and context appears to facilitate expression of the behavioral phenomenon. However, many unanswered questions remain concerning the persistence of and degree to which context influences locomotor sensitization to alcohol (ethanol). OBJECTIVES The goal of the present work was to determine the duration of locomotor sensitization to ethanol and the degree to which context dependence positively influences the induction, expression, and persistence of the behavioral phenomenon in female DBA/2J mice. MATERIALS AND METHODS Sensitized (with or without ethanol-paired exposure to the testing chamber) and non-sensitized saline control mice were left undisturbed in their home cages until subsequent ethanol challenge and testing in the locomotor activity testing chambers 7, 14, 21, 28, 42, 56, and/or 70 days after cessation of the ethanol sensitization procedure. Retro-orbital sinus bloods were sampled to determine whether the sensitization procedure had altered blood ethanol clearance rates. RESULTS Locomotor sensitization persisted through post-sensitization day 14, and repeated paring of the drug and testing context prolonged the expression of this phenomenon through at least post-sensitization day 28. Blood ethanol concentrations did not differ. CONCLUSIONS Locomotor sensitization to ethanol persists for some time after cessation of repeated ethanol exposure, and the association of contextual cues with the ethanol experience lengthens this persistence. The present data lay the groundwork for investigations into the neuroadaptive changes that underlie locomotor sensitization to ethanol in mice.
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Affiliation(s)
- Stephen L Boehm
- Behavioral Neuroscience, Department of Psychology, Binghamton University, Binghamton, NY 13902, USA.
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