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Li C, McCloskey NS, Inan S, Kirby LG. Role of serotonin neurons in the dorsal raphe nucleus in heroin self-administration and punishment. Neuropsychopharmacology 2025; 50:596-604. [PMID: 39300273 PMCID: PMC11735851 DOI: 10.1038/s41386-024-01993-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Revised: 09/05/2024] [Accepted: 09/09/2024] [Indexed: 09/22/2024]
Abstract
One hallmark of substance use disorder is continued drug use despite negative consequences. When drug-taking behavior is punished with aversive stimuli, i.e. footshock, rats can also be categorized into punishment-resistant or compulsive vs. punishment-sensitive or non-compulsive phenotypes. The serotonin (5-hydroxytryptamine, 5-HT) system modulates responses to both reward and punishment. The goal of the current study was to examine punishment phenotypes in heroin self-administration and to determine the role of dorsal raphe nucleus (DRN) 5-HT neurons in both basal and punished heroin self-administration. First, rats were exposed to punished heroin self-administration and neuronal excitability of DRN 5-HT neurons was compared between punishment-resistant and punishment-sensitive phenotypes using ex vivo electrophysiology. Second, DRN 5-HT neuronal activity was manipulated in vivo during basal and punished heroin self-administration using chemogenetic tools in a Tph2-iCre rat line. While rats separated into punishment-resistant and punishment-sensitive phenotypes for punished heroin self-administration, DRN 5-HT neuronal excitability did not differ between the phenotypes. While chemogenetic inhibition of DRN 5-HT neurons was without effect, chemogenetic activation of DRN 5-HT neurons increased both basal and punished heroin self-administration selectively in punishment-resistant animals. Additionally, the responsiveness to chemogenetic activation of DRN 5-HT neurons in basal self-administration and motivation for heroin in progressive ratio each predicted resistance to punishment. Therefore, our data support the role for the DRN 5-HT system in compulsive heroin self-administration.
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Affiliation(s)
- Chen Li
- Center for Substance Abuse Research, Lewis Katz School of Medicine at Temple University, Philadelphia, USA
| | - Nicholas S McCloskey
- Center for Substance Abuse Research, Lewis Katz School of Medicine at Temple University, Philadelphia, USA
| | - Saadet Inan
- Center for Substance Abuse Research, Lewis Katz School of Medicine at Temple University, Philadelphia, USA
| | - Lynn G Kirby
- Center for Substance Abuse Research, Lewis Katz School of Medicine at Temple University, Philadelphia, USA.
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Engeln M, Ahmed SH. Remission from addiction: erasing the wrong circuits or making new ones? Nat Rev Neurosci 2024:10.1038/s41583-024-00886-y. [PMID: 39663409 DOI: 10.1038/s41583-024-00886-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/07/2024] [Indexed: 12/13/2024]
Abstract
Chronic relapse is a hallmark of substance-use disorders (SUDs), but many people with SUDs do recover and eventually enter remission. Many preclinical studies in this field aim to identify interventions that can precipitate recovery by reversing or erasing the neuronal circuit changes caused by chronic drug use. A better understanding of remission from SUDs can also come from preclinical studies that model factors known to influence recovery in humans, such as the negative consequences of drug use and positive environmental influences. In this Perspective we discuss human neuroimaging studies that have provided information about recovery from SUDs and highlight mechanisms identified in preclinical studies - such as the reconfiguration of neuronal circuits - that could contribute to remission. We also analyse how studies of memory and forgetting can provide insights into the mechanisms of remission. Overall, we propose that remission can be driven by the introduction of new neuronal changes (which outcompete those induced by drugs) as well as by the erasure of drug-induced changes.
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Affiliation(s)
- Michel Engeln
- Univ. Bordeaux, CNRS, INCIA, UMR 5287, Bordeaux, France.
| | - Serge H Ahmed
- Univ. Bordeaux, CNRS, INCIA, UMR 5287, Bordeaux, France
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Engeln M, Ahmed SH. The multiple faces of footshock punishment in animal research on addiction. Neurobiol Learn Mem 2024; 213:107955. [PMID: 38944108 DOI: 10.1016/j.nlm.2024.107955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 06/05/2024] [Accepted: 06/20/2024] [Indexed: 07/01/2024]
Abstract
Continued drug use despite negative consequences is a hallmark of addiction commonly modelled in rodents using punished drug intake. Over the years, addiction research highlighted two subpopulations of punishment sensitive and resistant animals. While helpful to interrogate the neurobiology of drug-related behaviors, these procedures carry some weaknesses that need to be recognized and eventually defused. Mainly focusing on footshock-related work, we will first discuss the criteria used to define punishment-resistant animals and how their relative arbitrariness may impact our findings. With the overarching goal of improving our interpretation of the punishment-resistant phenotype, we will evaluate how tailored punishment protocols may better apprehend resistance to punishment, and how testing the robustness of punishment resistance could yield new results and strengthen interpretations. Second, we will question whether and to what extent punishment sensitivity, as currently defined, is reflective of abstinence and suggest that punishment resistance is, in fact, a prerequisite to model abstinence from addiction. Again, we will examine how challenging the robustness of the punishment-sensitive phenotype may help to better characterize it. Finally, we will evaluate whether diminished relapse-like behavior after repeated punishment-induced abstinence could not only contribute to better understand the mechanisms of abstinence, but also uniquely model progressive recovery (i.e., after repeated failed attempts at recovery) which is the norm in people with addiction. Altogether, by questioning the strengths and weaknesses of our models, we would like to open discussions on the different ways we interpret punishment sensitivity and resistance and the aspects that remain to be explored.
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Affiliation(s)
- Michel Engeln
- Univ. Bordeaux, CNRS, INCIA, UMR 5287, F-33000 Bordeaux, France.
| | - Serge H Ahmed
- Univ. Bordeaux, CNRS, INCIA, UMR 5287, F-33000 Bordeaux, France.
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Lee JG, Li Y, Kim NJ, Jang HB, Yang CH, Kim HY, Yoon SS, Chang S, Jeong SJ, Kim SC, Sa BS, Lee BH. A synergistic effect of herb and acupuncture on the methamphetamine. Integr Med Res 2024; 13:101052. [PMID: 39219986 PMCID: PMC11364119 DOI: 10.1016/j.imr.2024.101052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 05/20/2024] [Accepted: 05/30/2024] [Indexed: 09/04/2024] Open
Abstract
Background Herbal medicine Ja-Geum-Jeong (JGJ) has been used for the treatment of detoxification in Eastern Asia. However, the mechanisms involved are not clearly defined. The purpose of the present study was to investigate if herb medication inhibits Methamphetamine (METH)'s reinforcing effect and also examined if a combination of herb medication and acupuncture produces a synergistic effect on METH. Methods Male Sprague-Dawley rats were given acute METH intraperitoneally and the locomotor activity and ultrasonic vocalization (USV) calls were measured. Rats were administered JGJ orally and acupuncture was given at HT7 or SI5. Monosodium glutamate (MSG) and gamma-aminobutyric acid (GABA) agonists were injected into the Central amygdala (CeA) to investigate a possible neuroscientific mechanism. Tyrosine hydroxylase (TH) and fast scan cyclic voltammetry (FSCV) were measured to immunohistochemically and electrically confirm the behavioral data. Results Locomotor activity and USV calls were increased by METH (P < 0.05) and these increases were inhibited by JGJ (P < 0.05). Also, JGJ had no effect on the normal group given saline, and acupuncture at SI5 acupoint, but not at HT7 acupoint, produced a synergistic effect when combined with JGJ (P < 0.05). The JGJ's inhibition was blocked by the inactivation of CeA (P < 0.05), and MSG mimicked JGJ (P < 0.05). TH and FSCV measures showed the same pattern with the behavioral data (P < 0.05). Conclusion Results of the present study suggest that JGJ had inhibitory effects on the METH which was mediated through the activation of CeA and that combination of acupuncture and herb produced synergistic effect.
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Affiliation(s)
- Jin Gyeom Lee
- Department of Acupuncture, Moxibustion and Acupoint, College of Korean Medicine, Daegu Haany University, Daegu, Republic of Korea
- Research Center for Herbal Convergence on Liver Disease, Daegu Haany University, Gyeongsan, Republic of Korea
| | - Yuchi Li
- China Novartis Institutes for BioMedical Research, PR China
| | - Nam Jun Kim
- Department of Acupuncture, Moxibustion and Acupoint, College of Korean Medicine, Daegu Haany University, Daegu, Republic of Korea
- Research Center for Herbal Convergence on Liver Disease, Daegu Haany University, Gyeongsan, Republic of Korea
| | - Han Byeol Jang
- Department of Acupuncture, Moxibustion and Acupoint, College of Korean Medicine, Daegu Haany University, Daegu, Republic of Korea
- Research Center for Herbal Convergence on Liver Disease, Daegu Haany University, Gyeongsan, Republic of Korea
| | - Chae Ha Yang
- Department of Physiology, College of Korean Medicine, Daegu Haany University, Daegu, Republic of Korea
| | - Hee Young Kim
- Department of Physiology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Seong Shoon Yoon
- Department of Physiology, College of Korean Medicine, Daegu Haany University, Daegu, Republic of Korea
| | - Suchan Chang
- Department of Physiology, College of Korean Medicine, Daegu Haany University, Daegu, Republic of Korea
| | - Seon-Ju Jeong
- Department of Physiology, College of Korean Medicine, Daegu Haany University, Daegu, Republic of Korea
| | - Sang Chan Kim
- Research Center for Herbal Convergence on Liver Disease, Daegu Haany University, Gyeongsan, Republic of Korea
- Department of Herbal Formula, College of Biomedical Science, Daegu Haany University, Daegu, Republic of Korea
| | - Bok Suk Sa
- Chung Shin Herbal Medicine, Daegu, Republic of Korea
| | - Bong Hyo Lee
- Department of Acupuncture, Moxibustion and Acupoint, College of Korean Medicine, Daegu Haany University, Daegu, Republic of Korea
- Research Center for Herbal Convergence on Liver Disease, Daegu Haany University, Gyeongsan, Republic of Korea
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Nentwig TB, Obray JD, Kruyer A, Wilkes ET, Vaughan DT, Scofield MD, Chandler LJ. Central Amygdala Astrocyte Plasticity Underlies GABAergic Dysregulation in Ethanol Dependence. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.11.598470. [PMID: 38915577 PMCID: PMC11195260 DOI: 10.1101/2024.06.11.598470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Dependence is a hallmark of alcohol use disorder characterized by excessive alcohol intake and withdrawal symptoms. The central nucleus of the amygdala (CeA) is a key brain structure underlying the synaptic and behavioral consequences of ethanol dependence. While accumulating evidence suggests that astrocytes regulate synaptic transmission and behavior, there is a limited understanding of the role astrocytes play in ethanol dependence. The present study used a combination of viral labeling, super resolution confocal microscopy, 3D image analysis, and slice electrophysiology to determine the effects of chronic intermittent ethanol (CIE) exposure on astrocyte plasticity in the CeA. During withdrawal from CIE exposure, we observed increased GABA transmission, an upregulation in astrocytic GAT3 levels, and an increased proximity of astrocyte processes near CeA synapses. Furthermore, GAT3 levels and synaptic proximity were positively associated with voluntary ethanol drinking in dependent rats. Slice electrophysiology confirmed that the upregulation in astrocytic GAT3 levels was functional, as CIE exposure unmasked a GAT3-sensitive tonic GABA current in the CeA. A causal role for astrocytic GAT3 in ethanol dependence was assessed using viral-mediated GAT3 overexpression and knockdown approaches. However, GAT3 knockdown or overexpression had no effect on somatic withdrawal symptoms, dependence-escalated ethanol intake, aversion-resistant drinking, or post-dependent ethanol drinking in male or female rats. Moreover, intra-CeA pharmacological inhibition of GAT3 also did not alter dependent ethanol drinking. Together, these findings indicate that ethanol dependence induces GABAergic dysregulation and astrocyte plasticity in the CeA. However, astrocytic GAT3 does not appear necessary for the drinking related phenotypes associated with dependence.
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Affiliation(s)
- Todd B. Nentwig
- Department of Neuroscience, Medical University of South Carolina, Charleston SC 29425, United States
| | - J. Daniel Obray
- Department of Neuroscience, Medical University of South Carolina, Charleston SC 29425, United States
| | - Anna Kruyer
- Department of Neuroscience, Medical University of South Carolina, Charleston SC 29425, United States
- Current affiliation: Department of Neuroscience, University of Cincinnati, Cincinnati, OH, USA
| | - Erik T Wilkes
- Department of Neuroscience, Medical University of South Carolina, Charleston SC 29425, United States
| | - Dylan T. Vaughan
- Department of Neuroscience, Medical University of South Carolina, Charleston SC 29425, United States
- Current affiliation: Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michael D. Scofield
- Department of Neuroscience, Medical University of South Carolina, Charleston SC 29425, United States
| | - L. Judson Chandler
- Department of Neuroscience, Medical University of South Carolina, Charleston SC 29425, United States
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Heilig M, Witkiewitz K, Ray LA, Leggio L. Novel medications for problematic alcohol use. J Clin Invest 2024; 134:e172889. [PMID: 38828724 PMCID: PMC11142745 DOI: 10.1172/jci172889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024] Open
Abstract
Alcohol-related harm, a major cause of disease burden globally, affects people along a spectrum of use. When a harmful pattern of drinking is present in the absence of significant behavioral pathology, low-intensity brief interventions that provide information about health consequences of continued use provide large health benefits. At the other end of the spectrum, profound behavioral pathology, including continued use despite knowledge of potentially fatal consequences, warrants a medical diagnosis, and treatment is strongly indicated. Available behavioral and pharmacological treatments are supported by scientific evidence but are vastly underutilized. Discovery of additional medications, with a favorable balance of efficacy versus safety and tolerability can improve clinical uptake of treatment, allow personalized treatment, and improve outcomes. Here, we delineate the clinical conditions when pharmacotherapy should be considered in relation to the main diagnostic systems in use and discuss clinical endpoints that represent meaningful clinical benefits. We then review specific developments in three categories of targets that show promise for expanding the treatment toolkit. GPCRs remain the largest category of successful drug targets across contemporary medicine, and several GPCR targets are currently pursued for alcohol-related indications. Endocrine systems are another established category, and several promising targets have emerged for alcohol indications. Finally, immune modulators have revolutionized treatment of multiple medical conditions, and they may also hold potential to produce benefits in patients with alcohol problems.
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Affiliation(s)
- Markus Heilig
- Center for Social and Affective Neuroscience, Linköping University, and Department of Psychiatry, Linköping University Hospital, Linköping, Sweden
| | - Katie Witkiewitz
- Department of Psychology and Center on Alcohol, Substance Use and Addictions, University of New Mexico, Albuquerque, New Mexico, USA
| | - Lara A. Ray
- Department of Psychology, UCLA, Los Angeles, California, USA
| | - Lorenzo Leggio
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse Intramural Research Program and National Institute on Alcohol Abuse and Alcoholism Division of Intramural Clinical and Biological Research, NIH, Baltimore and Bethesda, Maryland, USA
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Chen W, Guo H, Zhou N, Mai Y, Hu T, Xu X, He T, Wen J, Qin S, Liu C, Wu W, Kim HY, Fan Y, Ge F, Guan X. Distinct eLPB ChAT projections for methamphetamine withdrawal anxiety and primed reinstatement of conditioned place preference. Theranostics 2024; 14:2881-2896. [PMID: 38773977 PMCID: PMC11103501 DOI: 10.7150/thno.95383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Accepted: 04/24/2024] [Indexed: 05/24/2024] Open
Abstract
Methamphetamine (METH) withdrawal anxiety symptom and relapse have been significant challenges for clinical practice, however, the underlying neuronal basis remains unclear. Our recent research has identified a specific subpopulation of choline acetyltransferase (ChAT+) neurons localized in the external lateral portion of parabrachial nucleus (eLPBChAT), which modulates METH primed-reinstatement of conditioned place preference (CPP). Here, the anatomical structures and functional roles of eLPBChAT projections in METH withdrawal anxiety and primed reinstatement were further explored. Methods: In the present study, a multifaceted approach was employed to dissect the LPBChAT+ projections in male mice, including anterograde and retrograde tracing, acetylcholine (Ach) indicator combined with fiber photometry recording, photogenetic and chemogenetic regulation, as well as electrophysiological recording. METH withdrawal anxiety-like behaviors and METH-primed reinstatement of conditioned place preference (CPP) were assessed in male mice. Results: We identified that eLPBChAT send projections to PKCδ-positive (PKCδ+) neurons in lateral portion of central nucleus of amygdala (lCeAPKCδ) and oval portion of bed nucleus of the stria terminalis (ovBNSTPKCδ), forming eLPBChAT-lCeAPKCδ and eLPBChAT-ovBNSTPKCδ pathways. At least in part, the eLPBChAT neurons positively innervate lCeAPKCδ neurons and ovBNSTPKCδ neurons through regulating synaptic elements of presynaptic Ach release and postsynaptic nicotinic acetylcholine receptors (nAChRs). METH withdrawal anxiety and METH-primed reinstatement of CPP respectively recruit eLPBChAT-lCeAPKCδ pathway and eLPBChAT-ovBNSTPKCδ pathway in male mice. Conclusion: Our findings put new insights into the complex neural networks, especially focusing on the eLPBChAT projections. The eLPBChAT is a critical node in the neural networks governing METH withdrawal anxiety and primed-reinstatement of CPP through its projections to the lCeAPKCδ and ovBNSTPKCδ, respectively.
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Affiliation(s)
- Wenwen Chen
- Department of Human Anatomy and Histoembryology, Nanjing University of Chinese Medicine, Nanjing, China
| | - Hao Guo
- Department of Human Anatomy and Histoembryology, Nanjing University of Chinese Medicine, Nanjing, China
| | - Ning Zhou
- Department of Human Anatomy and Histoembryology, Nanjing University of Chinese Medicine, Nanjing, China
| | - Yuning Mai
- Department of Human Anatomy and Histoembryology, Nanjing University of Chinese Medicine, Nanjing, China
| | - Tao Hu
- Department of Human Anatomy and Histoembryology, Nanjing University of Chinese Medicine, Nanjing, China
| | - Xing Xu
- Department of Human Anatomy and Histoembryology, Nanjing University of Chinese Medicine, Nanjing, China
| | - Teng He
- Department of Human Anatomy and Histoembryology, Nanjing University of Chinese Medicine, Nanjing, China
| | - Jun Wen
- Department of Human Anatomy and Histoembryology, Nanjing University of Chinese Medicine, Nanjing, China
| | - Shan Qin
- Department of Acupuncture-Moxibustion and Rehabilitation, Jiangsu Province Hospital of Chinese Medicine, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, China
| | - Chengyong Liu
- Department of Acupuncture-Moxibustion and Rehabilitation, Jiangsu Province Hospital of Chinese Medicine, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, China
| | - Wenzhong Wu
- Department of Acupuncture-Moxibustion and Rehabilitation, Jiangsu Province Hospital of Chinese Medicine, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, China
| | - Hee Young Kim
- Department of Physiology, Yonsei University College of Medicine, Seoul, South Korea
| | - Yu Fan
- Department of Human Anatomy and Histoembryology, Nanjing University of Chinese Medicine, Nanjing, China
| | - Feifei Ge
- Department of Human Anatomy and Histoembryology, Nanjing University of Chinese Medicine, Nanjing, China
| | - Xiaowei Guan
- Department of Human Anatomy and Histoembryology, Nanjing University of Chinese Medicine, Nanjing, China
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Uusi-Oukari M, Korpi ER. GABAergic mechanisms in alcohol dependence. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2024; 175:75-123. [PMID: 38555121 DOI: 10.1016/bs.irn.2024.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/02/2024]
Abstract
The target of alcohol's effect on the central nervous system has been sought for more than 50 years in the brain's GABA system. The behavioral and emotional effects of alcohol in humans and rodents are very similar to those of barbiturates and benzodiazepines, and GABAA receptors have been shown to be one of the sites of alcohol action. The mechanisms of GABAergic inhibition have been a hotspot of research but have turned out to be complex and controversial. Genetics support the involvement of some GABAA receptor subunits in the development of alcohol dependence and in alcohol use disorders (AUD). Since the effect of alcohol on the GABAA system resembles that of a GABAergic positive modulator, it may be possible to develop GABAergic drug treatments that could substitute for alcohol. The adaptation mechanisms of the GABA system and the plasticity of the brain are a big challenge for drug development: the drugs that act on GABAA receptors developed so far also may cause adaptation and development of additional addiction. Human polymorphisms should be studied further to get insight about how they affect receptor function, expression or other factors to make reasonable predictions/hypotheses about what non-addictive interventions would help in alcohol dependence and AUD.
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Affiliation(s)
- Mikko Uusi-Oukari
- Integrative Physiology and Pharmacology, Institute of Biomedicine, University of Turku, Turku, Finland
| | - Esa R Korpi
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
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Colombo G. Positive allosteric modulators of the GABAB receptor: a new class of ligands with therapeutic potential for alcohol use disorder. Alcohol Alcohol 2024; 59:agae018. [PMID: 38566580 DOI: 10.1093/alcalc/agae018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/22/2024] [Accepted: 03/08/2024] [Indexed: 04/04/2024] Open
Abstract
BACKGROUND Positive allosteric modulators (PAMs) of the GABAB receptor constitute a new class of GABAB-receptor ligands. GABAB PAMs reproduce several pharmacological effects of the orthosteric GABAB receptor agonist, baclofen, although displaying a better safety profile. AIMS This paper reviews the reducing or, frequently, even suppressing effects of all GABAB PAMs tested to date on multiple alcohol-related behaviours in laboratory rodents exposed to validated experimental models of human alcohol use disorder. RESULTS Acute or repeated treatment with CGP7930, GS39783, BHF177, rac-BHFF, ADX71441, CMPPE, COR659, ASP8062, KK-92A, and ORM-27669 reduced excessive alcohol drinking, relapse- and binge-like drinking, operant alcohol self-administration, reinstatement of alcohol seeking, and alcohol-induced conditioned place preference in rats and mice. CONCLUSIONS These effects closely mirrored those of baclofen; notably, they were associated to remarkably lower levels of tolerance and toxicity. The recent transition of ASP8062 to clinical testing will soon prove whether these highly consistent preclinical data translate to AUD patients.
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Affiliation(s)
- Giancarlo Colombo
- Neuroscience Institute, Section of Cagliari, National Research Council of Italy, I-09042, Monserrato (CA), Italy
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10
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Toivainen S, Xu L, Gobbo F, Della Valle A, Coppola A, Heilig M, Domi E. Different mechanisms underlie compulsive alcohol self-administration in male and female rats. Biol Sex Differ 2024; 15:17. [PMID: 38368341 PMCID: PMC10874042 DOI: 10.1186/s13293-024-00592-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 02/09/2024] [Indexed: 02/19/2024] Open
Abstract
BACKGROUND Sex is an important factor in the progression and treatment of alcohol addiction, and therapeutic approaches may have to be tailored to potential sex differences. This highlights the importance of understanding sex differences in behaviors that reflect key elements of clinical alcohol addiction, such as continued use despite negative consequences ("compulsive use"). Studies in experimental animals can help provide an understanding of the role sex plays to influence these behaviors. METHODS Large populations of genetically heterogeneous male and female Wistar rats were tested in an established model of compulsive alcohol self-administration, operationalized as alcohol responding despite contingent foot shock punishment. We also tested baseline (fixed ratio, unpunished) operant alcohol self-administration, motivation to self-administer alcohol (progressive ratio), and temporal discounting for alcohol reward. In search of predictors of compulsivity, animals were screened for novelty-induced place preference, anxiety-like behavior, pain sensitivity and corticosterone levels. The estrous cycle was monitored throughout the study. RESULTS Unpunished self-administration of alcohol did not differ between males and females when alcohol intake was corrected for body weight. Overall, females showed higher levels of compulsive responding for alcohol. Compulsive response rates showed bimodal distributions in male but not in female rats when intermediate shock intensities were used (0.2 and 0.25 mA); at higher shock intensities, responding was uniformly suppressed in both males and females. We also found less steep discounting in females when alcohol was devalued by delaying its delivery. Males exhibited a stronger motivation to obtain alcohol under unpunished conditions, while females showed higher corticosterone levels at baseline. Factor analysis showed that an underlying dimension related to stress and pain predicted compulsivity in females, while compulsivity in males was predicted by a reward factor. We did not find differences in alcohol-related behaviors throughout the various stages of the estrous cycle. CONCLUSIONS Our results suggest that mechanisms promoting compulsivity, a key feature of alcohol addiction, likely differ between males and females. This underscores the importance of considering sex as a biological variable in both preclinical and clinical research, and has potential treatment implications in alcohol addiction.
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Affiliation(s)
- Sanne Toivainen
- Center for Social and Affective Neuroscience, Department of Biomedical and Clinical Sciences, Linköping University, S-581 85, Linköping, Sweden
| | - Li Xu
- Center for Social and Affective Neuroscience, Department of Biomedical and Clinical Sciences, Linköping University, S-581 85, Linköping, Sweden
| | - Francesco Gobbo
- Centre for Discovery Brain Sciences, University of Edinburgh, 1 George Square, Edinburgh, EH8 9JZ, UK
| | - Andrea Della Valle
- School of Pharmacy, Center for Neuroscience, University of Camerino, 62032, Camerino, Italy
| | - Andrea Coppola
- Center for Social and Affective Neuroscience, Department of Biomedical and Clinical Sciences, Linköping University, S-581 85, Linköping, Sweden
| | - Markus Heilig
- Center for Social and Affective Neuroscience, Department of Biomedical and Clinical Sciences, Linköping University, S-581 85, Linköping, Sweden
| | - Esi Domi
- Center for Social and Affective Neuroscience, Department of Biomedical and Clinical Sciences, Linköping University, S-581 85, Linköping, Sweden.
- School of Pharmacy, Center for Neuroscience, University of Camerino, 62032, Camerino, Italy.
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