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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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Zhang J, Yan J, Li S, Chen Q, Lin J, Peng Y, Liu Y, Wang B, Wei X, Sun C, Niu S. GPR55 activation improves anxiety- and depression-like behaviors of mice during methamphetamine withdrawal. Heliyon 2024; 10:e30462. [PMID: 38720745 PMCID: PMC11077030 DOI: 10.1016/j.heliyon.2024.e30462] [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: 12/06/2023] [Revised: 04/26/2024] [Accepted: 04/26/2024] [Indexed: 05/12/2024] Open
Abstract
Methamphetamine is a potent and highly addictive neurotoxic psychostimulant that triggers a spectrum of adverse emotional responses during withdrawal. G-protein coupled receptor 55 (GPR55), a novel endocannabinoid receptor, is closely associated with mood regulation. Herein, we developed a murine model of methamphetamine-induced anxiety- and depressive-like behavior during abstinence which showed a decreased GPR55 expression in the hippocampus. Activation of GPR55 mitigated these behavioral symptoms, concomitantly ameliorating impairments in hippocampal neurogenesis and reducing neuroinflammation. These findings underscore the pivotal role of GPR55 in mediating the neuropsychological consequences of methamphetamine withdrawal, potentially via mechanisms involving the modulation of hippocampal neurogenesis and inflammation.
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Affiliation(s)
- Jinlong Zhang
- Department of Forensic Science, School of Basic Medical Science, Xinjiang Medical University, Urumqi, 830011, China
- Department of Forensic Science, School of Basic Medical Science, Central South University, Changsha, 410000, China
| | - Jie Yan
- Department of Forensic Science, School of Basic Medical Science, Xinjiang Medical University, Urumqi, 830011, China
- Department of Forensic Science, School of Basic Medical Science, Central South University, Changsha, 410000, China
| | - Shuyue Li
- Department of Forensic Science, School of Basic Medical Science, Xinjiang Medical University, Urumqi, 830011, China
| | - Qianqian Chen
- Department of Forensic Science, School of Basic Medical Science, Central South University, Changsha, 410000, China
| | - Jiang Lin
- Department of Forensic Science, School of Basic Medical Science, Central South University, Changsha, 410000, China
| | - Yilin Peng
- Department of Forensic Science, School of Basic Medical Science, Central South University, Changsha, 410000, China
| | - Yuhang Liu
- Department of Forensic Science, School of Basic Medical Science, Central South University, Changsha, 410000, China
| | - Binbin Wang
- Department of Forensic Science, School of Basic Medical Science, Central South University, Changsha, 410000, China
| | - Xinrong Wei
- Department of Forensic Science, School of Basic Medical Science, Xinjiang Medical University, Urumqi, 830011, China
| | - Chen Sun
- School of Public Health, Xinjiang Medical University, Urumqi, 830011, China
| | - Shuliang Niu
- Department of Forensic Science, School of Basic Medical Science, Xinjiang Medical University, Urumqi, 830011, China
- Department of Human Anatomy, School of Basic Medical Sciences, Xinjiang Medical University, Urumqi, 830011, China
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Elhadi K, Daiwile AP, Cadet JL. Modeling methamphetamine use disorder and relapse in animals: short- and long-term epigenetic, transcriptional., and biochemical consequences in the rat brain. Neurosci Biobehav Rev 2023; 155:105440. [PMID: 38707245 PMCID: PMC11068368 DOI: 10.1016/j.neubiorev.2023.105440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 10/13/2023] [Accepted: 10/24/2023] [Indexed: 05/07/2024]
Abstract
Methamphetamine use disorder (MUD) is a neuropsychiatric disorder characterized by binge drug taking episodes, intervals of abstinence, and relapses to drug use even during treatment. MUD has been modeled in rodents and investigators are attempting to identify its molecular bases. Preclinical experiments have shown that different schedules of methamphetamine self-administration can cause diverse transcriptional changes in the dorsal striatum of Sprague-Dawley rats. In the present review, we present data on differentially expressed genes (DEGs) identified in the rat striatum following methamphetamine intake. These include genes involved in transcription regulation, potassium channel function, and neuroinflammation. We then use the striatal data to discuss the potential significance of the molecular changes induced by methamphetamine by reviewing concordant or discordant data from the literature. This review identified potential molecular targets for pharmacological interventions. Nevertheless, there is a need for more research on methamphetamine-induced transcriptional consequences in various brain regions. These data should provide a more detailed neuroanatomical map of methamphetamine-induced changes and should better inform therapeutic interventions against MUD.
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Affiliation(s)
- Khalid Elhadi
- Molecular Neuropsychiatry Research Branch, NIH/NIDA Intramural Research Program, Baltimore, MD, 21224
| | - Atul P. Daiwile
- Molecular Neuropsychiatry Research Branch, NIH/NIDA Intramural Research Program, Baltimore, MD, 21224
| | - Jean Lud Cadet
- Molecular Neuropsychiatry Research Branch, NIH/NIDA Intramural Research Program, Baltimore, MD, 21224
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Basavarajappa BS, Subbanna S. Molecular Insights into Epigenetics and Cannabinoid Receptors. Biomolecules 2022; 12:1560. [PMID: 36358910 PMCID: PMC9687363 DOI: 10.3390/biom12111560] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 09/29/2022] [Accepted: 10/22/2022] [Indexed: 09/22/2023] Open
Abstract
The actions of cannabis are mediated by G protein-coupled receptors that are part of an endogenous cannabinoid system (ECS). ECS consists of the naturally occurring ligands N-arachidonylethanolamine (anandamide) and 2-arachidonoylglycerol (2-AG), their biosynthetic and degradative enzymes, and the CB1 and CB2 cannabinoid receptors. Epigenetics are heritable changes that affect gene expression without changing the DNA sequence, transducing external stimuli in stable alterations of the DNA or chromatin structure. Cannabinoid receptors are crucial candidates for exploring their functions through epigenetic approaches due to their significant roles in health and diseases. Epigenetic changes usually promote alterations in the expression of genes and proteins that can be evaluated by various transcriptomic and proteomic analyses. Despite the exponential growth of new evidence on the critical functions of cannabinoid receptors, much is still unknown regarding the contribution of various genetic and epigenetic factors that regulate cannabinoid receptor gene expression. Recent studies have identified several immediate and long-lasting epigenetic changes, such as DNA methylation, DNA-associated histone proteins, and RNA regulatory networks, in cannabinoid receptor function. Thus, they can offer solutions to many cellular, molecular, and behavioral impairments found after modulation of cannabinoid receptor activities. In this review, we discuss the significant research advances in different epigenetic factors contributing to the regulation of cannabinoid receptors and their functions under both physiological and pathological conditions. Increasing our understanding of the epigenetics of cannabinoid receptors will significantly advance our knowledge and could lead to the identification of novel therapeutic targets and innovative treatment strategies for diseases associated with altered cannabinoid receptor functions.
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Affiliation(s)
- Balapal S. Basavarajappa
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
- Molecular Imaging and Neuropathology Area, New York State Psychiatric Institute, New York, NY 10032, USA
- Department of Psychiatry, Columbia University Irving Medical Center, New York, NY 10032, USA
- Department of Psychiatry, New York University Langone Medical Center, New York, NY 10016, USA
| | - Shivakumar Subbanna
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
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Biochemical Neuroadaptations in the Rat Striatal Dopaminergic System after Prolonged Exposure to Methamphetamine Self-Administration. Int J Mol Sci 2022; 23:ijms231710092. [PMID: 36077488 PMCID: PMC9456063 DOI: 10.3390/ijms231710092] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 08/29/2022] [Accepted: 09/01/2022] [Indexed: 11/17/2022] Open
Abstract
Perturbations in striatal dopamine (DA) homeostasis might underlie the behavioral and pathobiological consequences of METH use disorder in humans. To identify potential consequences of long-term METH exposure, we modeled the adverse consequence DSM criterion of substance use disorders by giving footshocks to rats that had escalated their intake of METH during a drug self-administration procedure. Next, DA D1 receptor antagonist, SCH23390 was injected. Thereafter, rats were euthanized to measure several indices of the striatal dopaminergic system. Footshocks split the METH rats into two phenotypes: (i) shock-sensitive that decreased their METH-intake and (ii) shock-resistant that continued their METH intake. SCH23390 caused substantial dose-dependent reduction of METH taking in both groups. Stopping SCH23390 caused re-emergence of compulsive METH taking in shock-resistant rats. Compulsive METH takers also exhibited greater incubation of METH seeking than non-compulsive rats during withdrawal from METH SA. Analyses of DA metabolism revealed non-significant decreases (about 35%) in DA levels in resistant and sensitive rats. However, striatal contents of the deaminated metabolites, DOPAL and DOPAC, were significantly increased in sensitive rats. VMAT2 and DAT protein levels were decreased in both phenotypes. Moreover, protein expression levels of the D1-like DA receptor, D5R, and D2-like DA receptors, D3R and D4R, were significantly decreased in the compulsive METH takers. Our results parallel findings in post-mortem striatal tissues of human METH users who develop Parkinsonism after long-term METH intake and support the use of this model to investigate potential therapeutic interventions for METH use disorder.
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