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Cherry AL, Wheeler MJ, Mathisova K, Di Miceli M. In silico analyses of the involvement of GPR55, CB1R and TRPV1: response to THC, contribution to temporal lobe epilepsy, structural modeling and updated evolution. Front Neuroinform 2024; 18:1294939. [PMID: 38404644 PMCID: PMC10894036 DOI: 10.3389/fninf.2024.1294939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 01/19/2024] [Indexed: 02/27/2024] Open
Abstract
Introduction The endocannabinoid (eCB) system is named after the discovery that endogenous cannabinoids bind to the same receptors as the phytochemical compounds found in Cannabis. While endogenous cannabinoids include anandamide (AEA) and 2-arachidonoylglycerol (2-AG), exogenous phytocannabinoids include Δ-9 tetrahydrocannabinol (THC) and cannabidiol (CBD). These compounds finely tune neurotransmission following synapse activation, via retrograde signaling that activates cannabinoid receptor 1 (CB1R) and/or transient receptor potential cation channel subfamily V member 1 (TRPV1). Recently, the eCB system has been linked to several neurological diseases, such as neuro-ocular abnormalities, pain insensitivity, migraine, epilepsy, addiction and neurodevelopmental disorders. In the current study, we aim to: (i) highlight a potential link between the eCB system and neurological disorders, (ii) assess if THC exposure alters the expression of eCB-related genes, and (iii) identify evolutionary-conserved residues in CB1R or TRPV1 in light of their function. Methods To address this, we used several bioinformatic approaches, such as transcriptomic (Gene Expression Omnibus), protein-protein (STRING), phylogenic (BLASTP, MEGA) and structural (Phyre2, AutoDock, Vina, PyMol) analyzes. Results Using RNA sequencing datasets, we did not observe any dysregulation of eCB-related transcripts in major depressive disorders, bipolar disorder or schizophrenia in the anterior cingulate cortex, nucleus accumbens or dorsolateral striatum. Following in vivo THC exposure in adolescent mice, GPR55 was significantly upregulated in neurons from the ventral tegmental area, while other transcripts involved in the eCB system were not affected by THC exposure. Our results also suggest that THC likely induces neuroinflammation following in vitro application on mice microglia. Significant downregulation of TPRV1 occurred in the hippocampi of mice in which a model of temporal lobe epilepsy was induced, confirming previous observations. In addition, several transcriptomic dysregulations were observed in neurons of both epileptic mice and humans, which included transcripts involved in neuronal death. When scanning known interactions for transcripts involved in the eCB system (n = 12), we observed branching between the eCB system and neurophysiology, including proteins involved in the dopaminergic system. Our protein phylogenic analyzes revealed that CB1R forms a clade with CB2R, which is distinct from related paralogues such as sphingosine-1-phosphate, receptors, lysophosphatidic acid receptors and melanocortin receptors. As expected, several conserved residues were identified, which are crucial for CB1R receptor function. The anandamide-binding pocket seems to have appeared later in evolution. Similar results were observed for TRPV1, with conserved residues involved in receptor activation. Conclusion The current study found that GPR55 is upregulated in neurons following THC exposure, while TRPV1 is downregulated in temporal lobe epilepsy. Caution is advised when interpreting the present results, as we have employed secondary analyzes. Common ancestors for CB1R and TRPV1 diverged from jawless vertebrates during the late Ordovician, 450 million years ago. Conserved residues are identified, which mediate crucial receptor functions.
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Affiliation(s)
- Amy L. Cherry
- Worcester Biomedical Research Group, School of Science and the Environment, University of Worcester, Worcester, United Kingdom
| | - Michael J. Wheeler
- Sustainable Environments Research Group, School of Science and the Environment University of Worcester, Worcester, United Kingdom
| | - Karolina Mathisova
- School of Science and the Environment University of Worcester, Worcester, United Kingdom
| | - Mathieu Di Miceli
- Worcester Biomedical Research Group, School of Science and the Environment, University of Worcester, Worcester, United Kingdom
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2
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Zhu C, Lan X, Wei Z, Yu J, Zhang J. Allosteric modulation of G protein-coupled receptors as a novel therapeutic strategy in neuropathic pain. Acta Pharm Sin B 2024; 14:67-86. [PMID: 38239234 PMCID: PMC10792987 DOI: 10.1016/j.apsb.2023.07.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 06/09/2023] [Accepted: 07/12/2023] [Indexed: 01/22/2024] Open
Abstract
Neuropathic pain is a debilitating pathological condition that presents significant therapeutic challenges in clinical practice. Unfortunately, current pharmacological treatments for neuropathic pain lack clinical efficacy and often lead to harmful adverse reactions. As G protein-coupled receptors (GPCRs) are widely distributed throughout the body, including the pain transmission pathway and descending inhibition pathway, the development of novel neuropathic pain treatments based on GPCRs allosteric modulation theory is gaining momentum. Extensive research has shown that allosteric modulators targeting GPCRs on the pain pathway can effectively alleviate symptoms of neuropathic pain while reducing or eliminating adverse effects. This review aims to provide a comprehensive summary of the progress made in GPCRs allosteric modulators in the treatment of neuropathic pain, and discuss the potential benefits and adverse factors of this treatment. We will also concentrate on the development of biased agonists of GPCRs, and based on important examples of biased agonist development in recent years, we will describe universal strategies for designing structure-based biased agonists. It is foreseeable that, with the continuous improvement of GPCRs allosteric modulation and biased agonist theory, effective GPCRs allosteric drugs will eventually be available for the treatment of neuropathic pain with acceptable safety.
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Affiliation(s)
- Chunhao Zhu
- School of Pharmacy, Ningxia Medical University, Yinchuan 750004, China
- School of Basic Medical Science, Ningxia Medical University, Yinchuan 750004, China
| | - Xiaobing Lan
- School of Pharmacy, Ningxia Medical University, Yinchuan 750004, China
| | - Zhiqiang Wei
- Medicinal Chemistry and Bioinformatics Center, Ocean University of China, Qingdao 266100, China
| | - Jianqiang Yu
- School of Pharmacy, Ningxia Medical University, Yinchuan 750004, China
| | - Jian Zhang
- School of Pharmacy, Ningxia Medical University, Yinchuan 750004, China
- Medicinal Chemistry and Bioinformatics Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210023, China
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Luján MÁ, Covey DP, Young-Morrison R, Zhang L, Kim A, Morgado F, Patel S, Bass CE, Paladini C, Cheer JF. Mobilization of endocannabinoids by midbrain dopamine neurons is required for the encoding of reward prediction. Nat Commun 2023; 14:7545. [PMID: 37985770 PMCID: PMC10662422 DOI: 10.1038/s41467-023-43131-3] [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: 01/31/2023] [Accepted: 11/01/2023] [Indexed: 11/22/2023] Open
Abstract
Brain levels of the endocannabinoid 2-arachidonoylglycerol (2-AG) shape motivated behavior and nucleus accumbens (NAc) dopamine release. However, it is not clear whether mobilization of 2-AG specifically from midbrain dopamine neurons is necessary for dopaminergic responses to external stimuli predicting forthcoming reward. Here, we use a viral-genetic strategy to prevent the expression of the 2-AG-synthesizing enzyme diacylglycerol lipase α (DGLα) from ventral tegmental area (VTA) dopamine cells in adult mice. We find that DGLα deletion from VTA dopamine neurons prevents depolarization-induced suppression of excitation (DSE), a form of 2-AG-mediated synaptic plasticity, in dopamine neurons. DGLα deletion also decreases effortful, cue-driven reward-seeking but has no effect on non-cued or low-effort operant tasks and other behaviors. Moreover, dopamine recording in the NAc reveals that deletion of DGLα impairs the transfer of accumbal dopamine signaling from a reward to its earliest predictors. These results demonstrate that 2-AG mobilization from VTA dopamine neurons is a necessary step for the generation of dopamine-based predictive associations that are required to direct and energize reward-oriented behavior.
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Affiliation(s)
- Miguel Á Luján
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Dan P Covey
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Neuroscience, Lovelace Biomedical Research Institute, Albuquerque, NM, USA
| | - Reana Young-Morrison
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - LanYuan Zhang
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Andrew Kim
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Fiorella Morgado
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Sachin Patel
- Northwestern Center for Psychiatric Neuroscience, Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Caroline E Bass
- Department of Pharmacology and Toxicology, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - Carlos Paladini
- UTSA Neuroscience Institute, University of Texas at San Antonio, San Antonio, TX, USA
| | - Joseph F Cheer
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA.
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA.
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4
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Slézia A, Hegedüs P, Rusina E, Lengyel K, Solari N, Kaszas A, Balázsfi D, Botzanowski B, Acerbo E, Missey F, Williamson A, Hangya B. Behavioral, neural and ultrastructural alterations in a graded-dose 6-OHDA mouse model of early-stage Parkinson's disease. Sci Rep 2023; 13:19478. [PMID: 37945922 PMCID: PMC10636184 DOI: 10.1038/s41598-023-46576-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 11/02/2023] [Indexed: 11/12/2023] Open
Abstract
Studying animal models furthers our understanding of Parkinson's disease (PD) pathophysiology by providing tools to investigate detailed molecular, cellular and circuit functions. Different versions of the neurotoxin-based 6-hydroxydopamine (6-OHDA) model of PD have been widely used in rats. However, these models typically assess the result of extensive and definitive dopaminergic lesions that reflect a late stage of PD, leading to a paucity of studies and a consequential gap of knowledge regarding initial stages, in which early interventions would be possible. Additionally, the better availability of genetic tools increasingly shifts the focus of research from rats to mice, but few mouse PD models are available yet. To address these, we characterize here the behavioral, neuronal and ultrastructural features of a graded-dose unilateral, single-injection, striatal 6-OHDA model in mice, focusing on early-stage changes within the first two weeks of lesion induction. We observed early onset, dose-dependent impairments of overall locomotion without substantial deterioration of motor coordination. In accordance, histological evaluation demonstrated a partial, dose-dependent loss of dopaminergic neurons of substantia nigra pars compacta (SNc). Furthermore, electron microscopic analysis revealed degenerative ultrastructural changes in SNc dopaminergic neurons. Our results show that mild ultrastructural and cellular degradation of dopaminergic neurons of the SNc can lead to certain motor deficits shortly after unilateral striatal lesions, suggesting that a unilateral dose-dependent intrastriatal 6-OHDA lesion protocol can serve as a successful model of the early stages of Parkinson's disease in mice.
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Affiliation(s)
- Andrea Slézia
- Institute of Experimental Medicine, Lendület Laboratory of Systems Neuroscience, Budapest, Hungary.
- Institut de Neurosciences Des Systèmes, INSERM UMR S 1106, Aix-Marseille Université, Marseille, France.
- Institute of Cognitive Neuroscience and Psychology, Eotvos Lorand Research Network, Budapest, Hungary.
- Institut de Neurosciences de la Timone, CNRS UMR 7289, Aix-Marseille Université, Marseille, France.
| | - Panna Hegedüs
- Institute of Experimental Medicine, Lendület Laboratory of Systems Neuroscience, Budapest, Hungary
- János Szentágothai Doctoral School of Neurosciences, Semmelweis University, Budapest, Hungary
| | - Evgeniia Rusina
- Institut de Neurosciences Des Systèmes, INSERM UMR S 1106, Aix-Marseille Université, Marseille, France
| | - Katalin Lengyel
- Institute of Experimental Medicine, Lendület Laboratory of Systems Neuroscience, Budapest, Hungary
| | - Nicola Solari
- Institute of Experimental Medicine, Lendület Laboratory of Systems Neuroscience, Budapest, Hungary
| | - Attila Kaszas
- Institut de Neurosciences de la Timone, CNRS UMR 7289, Aix-Marseille Université, Marseille, France
| | - Diána Balázsfi
- Institute of Experimental Medicine, Lendület Laboratory of Systems Neuroscience, Budapest, Hungary
| | - Boris Botzanowski
- Institut de Neurosciences Des Systèmes, INSERM UMR S 1106, Aix-Marseille Université, Marseille, France
| | - Emma Acerbo
- Institut de Neurosciences Des Systèmes, INSERM UMR S 1106, Aix-Marseille Université, Marseille, France
| | - Florian Missey
- Institut de Neurosciences Des Systèmes, INSERM UMR S 1106, Aix-Marseille Université, Marseille, France
| | - Adam Williamson
- Institut de Neurosciences Des Systèmes, INSERM UMR S 1106, Aix-Marseille Université, Marseille, France.
- International Clinical Research Center (ICRC), St. Anne's University Hospital, Brno, Czech Republic.
| | - Balázs Hangya
- Institute of Experimental Medicine, Lendület Laboratory of Systems Neuroscience, Budapest, Hungary.
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Broussard JI, Redell JB, Zhao J, West R, Homma R, Dash PK. Optogenetic Stimulation of CA1 Pyramidal Neurons at Theta Enhances Recognition Memory in Brain Injured Animals. J Neurotrauma 2023; 40:2442-2448. [PMID: 37387400 PMCID: PMC10653071 DOI: 10.1089/neu.2023.0078] [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] [Indexed: 07/01/2023] Open
Abstract
Abstract The hippocampus plays a prominent role in learning and memory formation. The functional integrity of this structure is often compromised after traumatic brain injury (TBI), resulting in lasting cognitive dysfunction. The activity of hippocampal neurons, particularly place cells, is coordinated by local theta oscillations. Previous studies aimed at examining hippocampal theta oscillations after experimental TBI have reported disparate findings. Using a diffuse brain injury model, the lateral fluid percussion injury (FPI; 2.0 atm), we report a significant reduction in hippocampal theta power that persists for at least three weeks after injury. We questioned whether the behavioral deficit associated with this reduction of theta power can be overcome by optogenetically stimulating CA1 neurons at theta in brain injured rats. Our results show that memory impairments in brain injured animals could be reversed by optogenetically stimulating CA1 pyramidal neurons expressing channelrhodopsin (ChR2) during learning. In contrast, injured animals receiving a control virus (lacking ChR2) did not benefit from optostimulation. These results suggest that direct stimulation of CA1 pyramidal neurons at theta may be a viable option for enhancing memory after TBI.
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Affiliation(s)
- John I. Broussard
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, Texas, USA
| | - John B. Redell
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, Texas, USA
| | - Jing Zhao
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, Texas, USA
| | - Rebecca West
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, Texas, USA
| | - Ryota Homma
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, Texas, USA
| | - Pramod K. Dash
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, Texas, USA
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6
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Forsyth JK, Bearden CE. Rethinking the First Episode of Schizophrenia: Identifying Convergent Mechanisms During Development and Moving Toward Prediction. Am J Psychiatry 2023; 180:792-804. [PMID: 37908094 DOI: 10.1176/appi.ajp.20230736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Affiliation(s)
- Jennifer K Forsyth
- Department of Psychology, University of Washington, Seattle (Forsyth); Semel Institute for Neuroscience and Human Behavior, Department of Psychiatry and Behavioral Sciences, and Department of Psychology, University of California, Los Angeles (Bearden)
| | - Carrie E Bearden
- Department of Psychology, University of Washington, Seattle (Forsyth); Semel Institute for Neuroscience and Human Behavior, Department of Psychiatry and Behavioral Sciences, and Department of Psychology, University of California, Los Angeles (Bearden)
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7
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Steinfeld MR, Torregrossa MM. Consequences of adolescent drug use. Transl Psychiatry 2023; 13:313. [PMID: 37802983 PMCID: PMC10558564 DOI: 10.1038/s41398-023-02590-4] [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: 12/15/2022] [Revised: 05/22/2023] [Accepted: 08/23/2023] [Indexed: 10/08/2023] Open
Abstract
Substance use in adolescence is a known risk factor for the development of neuropsychiatric and substance use disorders in adulthood. This is in part due to the fact that critical aspects of brain development occur during adolescence, which can be altered by drug use. Despite concerted efforts to educate youth about the potential negative consequences of substance use, initiation remains common amongst adolescents world-wide. Additionally, though there has been substantial research on the topic, many questions remain about the predictors and the consequences of adolescent drug use. In the following review, we will highlight some of the most recent literature on the neurobiological and behavioral effects of adolescent drug use in rodents, non-human primates, and humans, with a specific focus on alcohol, cannabis, nicotine, and the interactions between these substances. Overall, consumption of these substances during adolescence can produce long-lasting changes across a variety of structures and networks which can have enduring effects on behavior, emotion, and cognition.
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Affiliation(s)
- Michael R Steinfeld
- Department of Psychiatry, University of Pittsburgh, 450 Technology Drive, Pittsburgh, PA, 15219, USA.
- Center for Neuroscience, University of Pittsburgh, 4200 Fifth Ave, Pittsburgh, PA, 15213, USA.
| | - Mary M Torregrossa
- Department of Psychiatry, University of Pittsburgh, 450 Technology Drive, Pittsburgh, PA, 15219, USA
- Center for Neuroscience, University of Pittsburgh, 4200 Fifth Ave, Pittsburgh, PA, 15213, USA
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8
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Shang H, Li P, Lin X, Cai Q, Li Z, Deng L, Song Y, Chen JF, Zhou J. Neuronal and astrocytic CB1R signaling differentially modulates goal-directed behavior and working memory by distinct temporal mechanisms. Neuropsychopharmacology 2023; 48:1520-1531. [PMID: 36694040 PMCID: PMC10425374 DOI: 10.1038/s41386-023-01533-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 12/26/2022] [Accepted: 12/27/2022] [Indexed: 01/26/2023]
Abstract
Several cognitive processes, including instrumental behavior and working memory, are controlled by endocannabinoids acting on cannabinoid receptor 1 (CB1R) in the brain through retrograde and presynaptic inhibition of GABA or glutamate release. However, the temporal mechanisms underlying the control of these cognitive processes by CB1Rs remain largely unknown. Here, we have developed a light-sensitive CB1R chimera (optoCB1R) by replacing the intracellular domains of bovine rhodopsin with those of human CB1R. We demonstrated that light stimulation of optoCB1R triggered canonical CB1R signaling by inhibiting cAMP (but not cGMP or IP1) signaling and activating the MAPK pathway in vitro or in vivo. Moreover, light stimulation of optoCB1R in corticostriatal glutamatergic neurons could temporally inhibit excitatory postsynaptic currents (EPSCs) at the level of seconds. Importantly, transient (3 s) and "time-locked", but not random, activation of optoCB1R signaling in corticostriatal neurons at the time of reward affected animal sensitivity to outcome devaluation and inhibited goal-directed behavior. However, prolonged (~30 min) but not transient (10 or 30 s) activation of astrocytic CB1R signaling in the hippocampus impaired working memory. Consequently, neuronal and astrocytic CB1R signaling differentially regulate working memory and goal-directed behavior through distinct temporal and cellular mechanisms. Ultimately, the pharmacological blockade of adenosine A2AR improved the neuronal and astrocytic CB1R-induced impairments in goal-directed behavior and working memory, possibly through modulation of EPSCs and c-Fos, respectively. Therefore, A2AR may represent a promising target for managing cognitive dysfunction resulting from the use of CB1R drugs.
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Affiliation(s)
- Huiping Shang
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Peijun Li
- Key Laboratory of Structural Malformations in Children of Zhejiang Province, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
| | - Xiangxiang Lin
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Qionghui Cai
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Zhihui Li
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Lu Deng
- Key Laboratory of Structural Malformations in Children of Zhejiang Province, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
| | - Yue Song
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Jiang-Fan Chen
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China.
| | - Jianhong Zhou
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China.
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Nufer TM, Wu BJ, Boyce Z, Steffensen SC, Edwards JG. Ethanol blocks a novel form of iLTD, but not iLTP of inhibitory inputs to VTA GABA neurons. Neuropsychopharmacology 2023; 48:1396-1408. [PMID: 36899030 PMCID: PMC10354227 DOI: 10.1038/s41386-023-01554-y] [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: 07/22/2022] [Revised: 02/14/2023] [Accepted: 02/16/2023] [Indexed: 03/12/2023]
Abstract
The ventral tegmental area (VTA) is an essential component of the mesocorticolimbic dopamine (DA) circuit that processes reward and motivated behaviors. The VTA contains DA neurons essential in this process, as well as GABAergic inhibitory cells that regulate DA cell activity. In response to drug exposure, synaptic connections of the VTA circuit can be rewired via synaptic plasticity-a phenomenon thought to be responsible for the pathology of drug dependence. While synaptic plasticity to VTA DA neurons as well as prefrontal cortex to nucleus accumbens GABA neurons are well studied, VTA GABA cell plasticity, specifically inhibitory inputs to VTA GABA neurons, is less understood. Therefore, we investigated the plasticity of these inhibitory inputs. Using whole cell electrophysiology in GAD67-GFP mice to identify GABA cells, we observed that these VTA GABA cells experience either inhibitory GABAergic long-term potentiation (iLTP) or inhibitory long-term depression (iLTD) in response to a 5 Hz stimulus. Paired pulse ratios, coefficient of variance, and failure rates suggest a presynaptic mechanism for both plasticity types, where iLTP is NMDA receptor-dependent and iLTD is GABAB receptor-dependent-this being the first report of iLTD onto VTA GABA cells. As illicit drug exposure can alter VTA plasticity, we employed chronic intermittent exposure (CIE) to ethanol (EtOH) vapor in male and female mice to examine its potential impact on VTA GABA input plasticity. Chronic EtOH vapor exposure produced measurable behavioral changes illustrating dependence and concomitantly prevented previously observed iLTD, which continued in air-exposed controls, illustrating the impact of EtOH on VTA neurocircuitry and suggesting physiologic mechanisms at play in alcohol use disorder and withdrawal states. Taken together, these novel findings of unique GABAergic synapses exhibiting either iLTP or iLTD within the mesolimbic circuit, and EtOH blockade specifically of iLTD, characterize inhibitory VTA plasticity as a malleable, experience-dependent system modified by EtOH.
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Affiliation(s)
- Teresa M Nufer
- Brigham Young University, Neuroscience Center, Provo, UT, 84602, USA
| | - Bridget J Wu
- Brigham Young University, Department of Cell Biology and Physiology Provo, Provo, UT, 84602, USA
| | - Zachary Boyce
- Brigham Young University, Neuroscience Center, Provo, UT, 84602, USA
| | | | - Jeffrey G Edwards
- Brigham Young University, Neuroscience Center, Provo, UT, 84602, USA.
- Brigham Young University, Department of Cell Biology and Physiology Provo, Provo, UT, 84602, USA.
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10
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Hasbi A, Madras BK, George SR. Endocannabinoid System and Exogenous Cannabinoids in Depression and Anxiety: A Review. Brain Sci 2023; 13:brainsci13020325. [PMID: 36831868 PMCID: PMC9953886 DOI: 10.3390/brainsci13020325] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 02/10/2023] [Accepted: 02/11/2023] [Indexed: 02/17/2023] Open
Abstract
Background: There is a growing liberalization of cannabis-based preparations for medical and recreational use. In multiple instances, anxiety and depression are cited as either a primary or a secondary reason for the use of cannabinoids. Aim: The purpose of this review is to explore the association between depression or anxiety and the dysregulation of the endogenous endocannabinoid system (ECS), as well as the use of phytocannabinoids and synthetic cannabinoids in the remediation of depression/anxiety symptoms. After a brief description of the constituents of cannabis, cannabinoid receptors and the endocannabinoid system, the most important evidence is presented for the involvement of cannabinoids in depression and anxiety both in human and from animal models of depression and anxiety. Finally, evidence is presented for the clinical use of cannabinoids to treat depression and anxiety. Conclusions: Although the common belief that cannabinoids, including cannabis, its main studied components-tetrahydrocannabinol (THC) and cannabidiol (CBD)-or other synthetic derivatives have been suggested to have a therapeutic role for certain mental health conditions, all recent systematic reviews that we report have concluded that the evidence that cannabinoids improve depressive and anxiety disorders is weak, of very-low-quality, and offers no guidance on the use of cannabinoids for mental health conditions within a regulatory framework. There is an urgent need for high-quality studies examining the effects of cannabinoids on mental disorders in general and depression/anxiety in particular, as well as the consequences of long-term use of these preparations due to possible risks such as addiction and even reversal of improvement.
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Affiliation(s)
- Ahmed Hasbi
- Department of Pharmacology and Toxicology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
- Correspondence: (A.H.); (S.R.G.)
| | - Bertha K. Madras
- McLean Hospital, Belmont, MA 02478, USA
- Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA
| | - Susan R. George
- Department of Pharmacology and Toxicology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Medicine, Temerty Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
- Correspondence: (A.H.); (S.R.G.)
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11
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Cannabinoid CB1 Receptors Are Expressed in a Subset of Dopamine Neurons and Underlie Cannabinoid-Induced Aversion, Hypoactivity, and Anxiolytic Effects in Mice. J Neurosci 2023; 43:373-385. [PMID: 36517243 PMCID: PMC9864584 DOI: 10.1523/jneurosci.1493-22.2022] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 10/12/2022] [Accepted: 11/12/2022] [Indexed: 12/23/2022] Open
Abstract
Cannabinoids modulate dopamine (DA) transmission and DA-related behavior, which has been thought to be mediated initially by activation of cannabinoid CB1 receptors (CB1Rs) on GABA neurons. However, there is no behavioral evidence supporting it. In contrast, here we report that CB1Rs are also expressed in a subset of DA neurons and functionally underlie cannabinoid action in male and female mice. RNAscope in situ hybridization (ISH) assays demonstrated CB1 mRNA in tyrosine hydroxylase (TH)-positive DA neurons in the ventral tegmental area (VTA) and glutamate decarboxylase 1 (GAD1)-positive GABA neurons. The CB1R-expressing DA neurons were located mainly in the middle portion of the VTA with the number of CB1-TH colocalization progressively decreasing from the medial to the lateral VTA. Triple-staining assays indicated CB1R mRNA colocalization with both TH and vesicular glutamate transporter 2 (VgluT2, a glutamate neuronal marker) in the medial VTA close to the midline of the brain. Optogenetic activation of this population of DA neurons was rewarding as assessed by optical intracranial self-stimulation. Δ9-tetrahydrocannabinol (Δ9-THC) or ACEA (a selective CB1R agonist) dose-dependently inhibited optical intracranial self-stimulation in DAT-Cre control mice, but not in conditional knockout mice with the CB1R gene absent in DA neurons. In addition, deletion of CB1Rs from DA neurons attenuated Δ9-THC-induced reduction in DA release in the NAc, locomotion, and anxiety. Together, these findings indicate that CB1Rs are expressed in a subset of DA neurons that corelease DA and glutamate, and functionally underlie cannabinoid modulation of DA release and DA-related behavior.SIGNIFICANCE STATEMENT Cannabinoids produce a series of psychoactive effects, such as aversion, anxiety, and locomotor inhibition in rodents. However, the cellular and receptor mechanisms underlying these actions are not fully understood. Here we report that CB1 receptors are expressed not only in GABA neurons but also in a subset of dopamine neurons, which are located mainly in the medial VTA close to the midline of the midbrain and corelease dopamine and glutamate. Optogenetic activation of these dopamine neurons is rewarding, which is dose-dependently inhibited by cannabinoids. Selective deletion of CB1 receptor from dopamine neurons blocked cannabinoid-induced aversion, hypoactivity, and anxiolytic effects. These findings demonstrate that dopaminergic CB1 receptors play an important role in mediating cannabinoid action.
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Gómez-Cañas M, Rodríguez-Cueto C, Satta V, Hernández-Fisac I, Navarro E, Fernández-Ruiz J. Endocannabinoid-Binding Receptors as Drug Targets. Methods Mol Biol 2023; 2576:67-94. [PMID: 36152178 DOI: 10.1007/978-1-0716-2728-0_6] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Cannabis plant has been used from ancient times with therapeutic purposes for treating human pathologies, but the identification of the cellular and molecular mechanisms underlying the therapeutic properties of the phytocannabinoids, the active compounds in this plant, occurred in the last years of the past century. In the late 1980s and early 1990s, seminal studies demonstrated the existence of cannabinoid receptors and other elements of the so-called endocannabinoid system. These G protein-coupled receptors (GPCRs) are a key element in the functions assigned to endocannabinoids and appear to serve as promising pharmacological targets. They include CB1, CB2, and GPR55, but also non-GPCRs can be activated by endocannabinoids, like ionotropic receptor TRPV1 and even nuclear receptors of the PPAR family. Their activation, inhibition, or simply modulation have been associated with numerous physiological effects at both central and peripheral levels, which may have therapeutic value in different human pathologies, then providing a solid experimental explanation for both the ancient medicinal uses of Cannabis plant and the recent advances in the development of cannabinoid-based specific therapies. This chapter will review the scientific knowledge generated in the last years around the research on the different endocannabinoid-binding receptors and their signaling mechanisms. Our intention is that this knowledge may help readers to understand the relevance of these receptors in health and disease conditions, as well as it may serve as the theoretical basis for the different experimental protocols to investigate these receptors and their signaling mechanisms that will be described in the following chapters.
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Affiliation(s)
- María Gómez-Cañas
- Instituto Universitario de Investigación en Neuroquímica, Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
- Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Carmen Rodríguez-Cueto
- Instituto Universitario de Investigación en Neuroquímica, Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
- Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Valentina Satta
- Instituto Universitario de Investigación en Neuroquímica, Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
- Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Inés Hernández-Fisac
- Instituto Universitario de Investigación en Neuroquímica, Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense, Madrid, Spain
| | - Elisa Navarro
- Instituto Universitario de Investigación en Neuroquímica, Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
- Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Javier Fernández-Ruiz
- Instituto Universitario de Investigación en Neuroquímica, Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense, Madrid, Spain.
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain.
- Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain.
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Therapeutic potential of PIMSR, a novel CB1 receptor neutral antagonist, for cocaine use disorder: evidence from preclinical research. Transl Psychiatry 2022; 12:286. [PMID: 35851573 PMCID: PMC9293959 DOI: 10.1038/s41398-022-02059-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 06/21/2022] [Accepted: 07/04/2022] [Indexed: 11/08/2022] Open
Abstract
Cannabinoid CB1 receptors (CB1Rs) have been major targets in medication development for the treatment of substance use disorders. However, clinical trials with rimonabant, a CB1R antagonist/inverse agonist, failed due to severe side effects. Here, we evaluated the therapeutic potential of PIMSR, a neutral CB1R antagonist lacking an inverse agonist profile, against cocaine's behavioral effects in experimental animals. We found that systemic administration of PIMSR dose-dependently inhibited cocaine self-administration under fixed-ratio (FR5), but not FR1, reinforcement, shifted the cocaine self-administration dose-response curve downward, decreased incentive motivation to seek cocaine under progressive-ratio reinforcement, and reduced cue-induced reinstatement of cocaine seeking. PIMSR also inhibited oral sucrose self-administration. Importantly, PIMSR alone is neither rewarding nor aversive as assessed by place conditioning. We then used intracranial self-stimulation (ICSS) to explore the possible involvement of the mesolimbic dopamine system in PIMSR's action. We found that PIMSR dose-dependently attenuated cocaine-enhanced ICSS maintained by electrical stimulation of the medial forebrain bundle in rats. PIMSR itself failed to alter electrical ICSS, but dose-dependently inhibited ICSS maintained by optical stimulation of midbrain dopamine neurons in transgenic DAT-Cre mice, suggesting the involvement of dopamine-dependent mechanisms. Lastly, we examined the CB1R mechanisms underlying PIMSR's action. We found that PIMSR pretreatment attenuated Δ9-tetrahydrocannabinol (Δ9-THC)- or ACEA (a selective CB1R agonist)-induced reduction in optical ICSS. Together, our findings suggest that the neutral CB1R antagonist PIMSR deserves further research as a promising pharmacotherapeutic for cocaine use disorder.
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Hasbi A, Madras BK, George SR. Daily THC and withdrawal increase dopamine D1-D2 receptor heteromer to mediate anhedonia and anxiogenic-like behavior through a dynorphin and kappa opioid receptor mechanism. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2022. [PMID: 37519471 PMCID: PMC10382712 DOI: 10.1016/j.bpsgos.2022.07.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022] Open
Abstract
Background Frequent cannabis use is associated with a higher risk of developing cannabis use disorder and other adverse consequences. However, rodent models studying the underlying mechanisms of the reinforcing and withdrawal effects of the primary constituent of cannabis, Δ9-tetrahydrocannabinol (THC), have been limited. Methods This study investigated the effects of daily THC (1 mg/kg, intraperitoneal, 9 days) and spontaneous withdrawal (7 days) on hedonic and aversion-like behaviors in male rats. In parallel, underlying neuroadaptive changes in dopaminergic, opioidergic, and cannabinoid signaling in the nucleus accumbens were evaluated, along with a candidate peptide designed to reverse altered signaling. Results Chronic THC administration induced anhedonic- and anxiogenic-like behaviors not attributable to altered locomotor activity. These effects persisted after drug cessation. In the nucleus accumbens, THC treatment and withdrawal catalyzed increased cannabinoid CB1 receptor activity without modifying receptor expression. Dopamine D1-D2 receptor heteromer expression rose steeply with THC, accompanied by increased calcium-linked signaling, activation of BDNF/TrkB (brain-derived neurotrophic factor/tropomyosin receptor kinase B) pathway, dynorphin expression, and kappa opioid receptor signaling. Disruption of the D1-D2 heteromer by an interfering peptide during withdrawal reversed the anxiogenic-like and anhedonic-like behaviors as well as the neurochemical changes. Conclusions Chronic THC increases nucleus accumbens dopamine D1-D2 receptor heteromer expression and function, which results in increased dynorphin expression and kappa opioid receptor activation. These changes plausibly reduce dopamine release to trigger anxiogenic- and anhedonic-like behaviors after daily THC administration that persist for at least 7 days after drug cessation. These findings conceivably provide a therapeutic strategy to alleviate negative symptoms associated with cannabis use and withdrawal.
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Liu Z, Yang N, Dong J, Tian W, Chang L, Ma J, Guo J, Tan J, Dong A, He K, Zhou J, Cinar R, Wu J, Salinas AG, Sun L, Kumar M, Sullivan BT, Oldham BB, Pitz V, Makarious MB, Ding J, Kung J, Xie C, Hawes SL, Wang L, Wang T, Chan P, Zhang Z, Le W, Chen S, Lovinger DM, Blauwendraat C, Singleton AB, Cui G, Li Y, Cai H, Tang B. Deficiency in endocannabinoid synthase DAGLB contributes to early onset Parkinsonism and murine nigral dopaminergic neuron dysfunction. Nat Commun 2022; 13:3490. [PMID: 35715418 PMCID: PMC9205912 DOI: 10.1038/s41467-022-31168-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 06/07/2022] [Indexed: 11/09/2022] Open
Abstract
Endocannabinoid (eCB), 2-arachidonoyl-glycerol (2-AG), the most abundant eCB in the brain, regulates diverse neural functions. Here we linked multiple homozygous loss-of-function mutations in 2-AG synthase diacylglycerol lipase β (DAGLB) to an early onset autosomal recessive Parkinsonism. DAGLB is the main 2-AG synthase in human and mouse substantia nigra (SN) dopaminergic neurons (DANs). In mice, the SN 2-AG levels were markedly correlated with motor performance during locomotor skill acquisition. Genetic knockdown of Daglb in nigral DANs substantially reduced SN 2-AG levels and impaired locomotor skill learning, particularly the across-session learning. Conversely, pharmacological inhibition of 2-AG degradation increased nigral 2-AG levels, DAN activity and dopamine release and rescued the locomotor skill learning deficits. Together, we demonstrate that DAGLB-deficiency contributes to the pathogenesis of Parkinsonism, reveal the importance of DAGLB-mediated 2-AG biosynthesis in nigral DANs in regulating neuronal activity and dopamine release, and suggest potential benefits of 2-AG augmentation in alleviating Parkinsonism.
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Affiliation(s)
- Zhenhua Liu
- Transgenic Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
- Department of Neurology, Xiangya Hospital, Central South University, 410008, Changsha, Hunan, China
| | - Nannan Yang
- Transgenic Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
- Department of Neurology, Xiangya Hospital, Central South University, 410008, Changsha, Hunan, China
| | - Jie Dong
- Transgenic Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
- Clinical Research Center on Neurological Diseases, the First Affiliated Hospital, Dalian Medical University, 116011, Dalian, Liaoning, China
| | - Wotu Tian
- Transgenic Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
- Department of Neurology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 20025, Shanghai, China
| | - Lisa Chang
- Transgenic Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jinghong Ma
- Department of Neurology, Xuanwu Hospital of Capital Medical University, 100053, Beijing, China
| | - Jifeng Guo
- Department of Neurology, Xiangya Hospital, Central South University, 410008, Changsha, Hunan, China
| | - Jieqiong Tan
- Centre for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, 410008, Changsha, Hunan, China
| | - Ao Dong
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, 100871, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, 100871, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China
| | - Kaikai He
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, 100871, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, 100871, Beijing, China
| | - Jingheng Zhou
- In Vivo Neurobiology Group, Neurobiology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC, 27709, USA
| | - Resat Cinar
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Junbing Wu
- Transgenic Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Armando G Salinas
- Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, MD, 20852, USA
| | - Lixin Sun
- Transgenic Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Mantosh Kumar
- Transgenic Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Breanna T Sullivan
- Transgenic Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Braden B Oldham
- Transgenic Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Vanessa Pitz
- Molecular Genetics Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Mary B Makarious
- Molecular Genetics Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jinhui Ding
- Computational Biology Group, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Justin Kung
- Transgenic Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Chengsong Xie
- Transgenic Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Sarah L Hawes
- Transgenic Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Lupeng Wang
- Transgenic Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Tao Wang
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022, Wuhan, Hubei, China
| | - Piu Chan
- Department of Neurology, Xuanwu Hospital of Capital Medical University, 100053, Beijing, China
| | - Zhuohua Zhang
- Centre for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, 410008, Changsha, Hunan, China
- Department of Neurosciences, University of South China Medical School, 421200, Hengyang, Hunan, China
| | - Weidong Le
- Clinical Research Center on Neurological Diseases, the First Affiliated Hospital, Dalian Medical University, 116011, Dalian, Liaoning, China
- Institute of Neurology, Sichuan Academy of Medical Sciences-Sichuan Provincial Hospital, Medical School of University of Electronics & Technology of China, 610045, Chengdu, Sichuan, China
| | - Shengdi Chen
- Department of Neurology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 20025, Shanghai, China
| | - David M Lovinger
- Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, MD, 20852, USA
| | - Cornelis Blauwendraat
- Integrative Neurogenomics Unit, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Andrew B Singleton
- Molecular Genetics Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
- Center for Alzheimer's and Related Dementias, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Guohong Cui
- In Vivo Neurobiology Group, Neurobiology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC, 27709, USA
| | - Yulong Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, 100871, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, 100871, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China
- Chinese Institute for Brain Research, 102206, Beijing, China
| | - Huaibin Cai
- Transgenic Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Beisha Tang
- Department of Neurology, Xiangya Hospital, Central South University, 410008, Changsha, Hunan, China.
- Centre for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, 410008, Changsha, Hunan, China.
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, 410008, Changsha, Hunan, China.
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, 410008, Changsha, Hunan, China.
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Inhibiting Endocannabinoid Hydrolysis as Emerging Analgesic Strategy Targeting a Spectrum of Ion Channels Implicated in Migraine Pain. Int J Mol Sci 2022; 23:ijms23084407. [PMID: 35457225 PMCID: PMC9027089 DOI: 10.3390/ijms23084407] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/08/2022] [Accepted: 04/13/2022] [Indexed: 12/23/2022] Open
Abstract
Migraine is a disabling neurovascular disorder characterized by severe pain with still limited efficient treatments. Endocannabinoids, the endogenous painkillers, emerged, alternative to plant cannabis, as promising analgesics against migraine pain. In this thematic review, we discuss how inhibition of the main endocannabinoid-degrading enzymes, monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH), could raise the level of endocannabinoids (endoCBs) such as 2-AG and anandamide in order to alleviate migraine pain. We describe here: (i) migraine pain signaling pathways, which could serve as specific targets for antinociception; (ii) a divergent distribution of MAGL and FAAH activities in the key regions of the PNS and CNS implicated in migraine pain signaling; (iii) a complexity of anti-nociceptive effects of endoCBs mediated by cannabinoid receptors and through a direct modulation of ion channels in nociceptive neurons; and (iv) the spectrum of emerging potent MAGL and FAAH inhibitors which efficiently increase endoCBs levels. The specific distribution and homeostasis of endoCBs in the main regions of the nociceptive system and their generation ‘on demand’, along with recent availability of MAGL and FAAH inhibitors suggest new perspectives for endoCBs-mediated analgesia in migraine pain.
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Asth L, Santos AC, Moreira FA. The endocannabinoid system and drug-associated contextual memories. Behav Pharmacol 2022; 33:90-104. [PMID: 33491992 DOI: 10.1097/fbp.0000000000000621] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Drug abuse and addiction can be initiated and reinstated by contextual stimuli previously paired with the drug use. The influence exerted by the context on drug-seeking behaviour can be modelled in experimental animals with place-conditioning protocols. Here, we review the effects of cannabinoids in place conditioning and the therapeutic potential of the endocannabinoid system for interfering with drug-related memories. The phytocannabinoid Δ9-tetrahydrocannabinol (THC) tends to induce conditioned place preference (CPP) at low doses and conditioned place aversion at high doses; cannabidiol is devoid of any effect, yet it inhibits CPP induced by some drugs. Synthetic CB1 receptor agonists tend to recapitulate the biphasic profile observed with THC, whereas selective antagonists/inverse agonists inhibit CPP induced by cocaine, nicotine, alcohol and opioids. However, their therapeutic use is limited by potential psychiatric side effects. The CB2 receptor has also attracted attention, because selective CB2 receptor agonists inhibit cocaine-induced CPP. Inhibitors of endocannabinoid membrane transport and hydrolysis yield mixed results. In targeting the endocannabinoid system for developing new treatments for drug addiction, future research should focus on 'neutral' CB1 receptor antagonists and CB2 receptor agonists. Such compounds may offer a well-tolerated pharmacological profile and curb addiction by preventing drug-seeking triggered by conditioned contextual cues.
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Affiliation(s)
- Laila Asth
- Department of Pharmacology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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Almeida MM, Dias-Rocha CP, Calviño C, Trevenzoli IH. Lipid endocannabinoids in energy metabolism, stress and developmental programming. Mol Cell Endocrinol 2022; 542:111522. [PMID: 34843899 DOI: 10.1016/j.mce.2021.111522] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 11/09/2021] [Accepted: 11/23/2021] [Indexed: 12/12/2022]
Abstract
The endocannabinoid system (ECS) regulates brain development and function, energy metabolism and stress in a sex-, age- and tissue-dependent manner. The ECS comprises mainly the bioactive lipid ligands anandamide (AEA) and 2-aracdonoylglycerol (2-AG), cannabinoid receptors 1 and 2 (CB1 and CB2), and several metabolizing enzymes. The endocannabinoid tonus is increased in obesity, stimulating food intake and a preference for fat, reward, and lipid accumulation in peripheral tissues, as well as favoring a positive energy balance. Energy balance and stress responses share adaptive mechanisms regulated by the ECS that seem to underlie the complex relationship between feeding and emotional behavior. The ECS is also a key regulator of development. Environmental insults (diet, toxicants, and stress) in critical periods of developmental plasticity, such as gestation, lactation and adolescence, alter the ECS and may predispose individuals to the development of chronic diseases and behavioral changes in the long term. This review is focused on the ECS and the developmental origins of health and disease (DOHaD).
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Affiliation(s)
- Mariana Macedo Almeida
- Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, RJ, Brazil
| | | | - Camila Calviño
- Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, RJ, Brazil
| | - Isis Hara Trevenzoli
- Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, RJ, Brazil.
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Deng L, Viray K, Singh S, Cravatt B, Stella N. ABHD6 Controls Amphetamine-Stimulated Hyperlocomotion: Involvement of CB 1 Receptors. Cannabis Cannabinoid Res 2021; 7:188-198. [PMID: 34705543 PMCID: PMC9070749 DOI: 10.1089/can.2021.0066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Introduction: Activation of cannabinoid 1 receptors (CB1Rs) by endocannabinoids (eCBs) is controlled by both eCB production and eCB inactivation. Accordingly, inhibition of eCB hydrolyzing enzymes, monoacylglycerol lipase (MAGL) and α/β-hydrolase domain containing 6 (ABHD6), enhances eCB accumulation and CB1R activation. It is known that inhibition of MAGL regulates select CB1R-dependent behaviors in mice, including locomotor behaviors and their modulation by psychostimulants, but much less is known about the effect of inhibiting ABHD6 activity on such behaviors. Methods: We report a new mouse line that carries a genetic deletion of Abhd6 and evaluated its effect on spontaneous locomotion measured in a home cage monitoring system, motor coordination measured on a Rotarod, and amphetamine-stimulated hyperlocomotion and amphetamine sensitization (AS) measured in an open-field chamber. Results: ABHD6 knockout (KO) mice reached adulthood without exhibiting overt behavioral impairment, and we measured only mild reduction in spontaneous locomotion and motor coordination in adult ABHD6 KO mice compared to wild-type (WT) mice. Significantly, amphetamine-stimulated hyperlocomotion was enhanced by twofold in ABHD6 KO mice compared to WT mice and yet ABHD6 KO mice expressed AS to the same extent as WT mice. A twofold increase in amphetamine-stimulated hyperlocomotion was also measured in ABHD6 heterozygote mice and in WT mice treated with the ABHD6 inhibitor KT-182. It is known that amphetamine-stimulated hyperlocomotion is not affected by the CB1R antagonist, SR141617, and we discovered that the enhanced amphetamine-stimulated hyperlocomotion resulting from ABHD6 inhibition is blocked by SR141617. Conclusions: Our study suggests that ABHD6 controls amphetamine-stimulated hyperlocomotion by a mechanistic switch to a CB1R-dependent mechanism.
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Affiliation(s)
- Liting Deng
- Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Katie Viray
- Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Simar Singh
- Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Ben Cravatt
- Department of Chemistry, The Scripps Research Institute, La Jolla, California, USA
| | - Nephi Stella
- Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington, USA.,Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, Washington, USA
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Engi SA, Beebe EJ, Ayvazian VM, Cruz FC, Cheer JF, Wenzel JM, Zlebnik NE. Cocaine-induced increases in motivation require 2-arachidonoylglycerol mobilization and CB1 receptor activation in the ventral tegmental area. Neuropharmacology 2021; 193:108625. [PMID: 34058192 PMCID: PMC8312311 DOI: 10.1016/j.neuropharm.2021.108625] [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: 01/31/2021] [Revised: 05/13/2021] [Accepted: 05/24/2021] [Indexed: 11/15/2022]
Abstract
A wide body of evidence supports an integral role for mesolimbic dopamine (DA) in motivated behavior. In brief, drugs that increase DA in mesolimbic terminal regions, like cocaine, enhance motivation, while drugs that decrease DA concentration reduce motivation. Data from our laboratory and others shows that phasic activation of mesolimbic DA requires signaling at cannabinoid type-1 (CB1) receptors in the ventral tegmental area (VTA), and systemic delivery of CB1 receptor antagonists reduces DA cell activity and attenuates motivated behaviors. Recent findings demonstrate that cocaine mobilizes the endocannabinoid 2-arachidonoylglycerol (2-AG) in the VTA to cause phasic activation of DA neurons and terminal DA release. It remains unclear, however, if cocaine-induced midbrain 2-AG signaling contributes to the motivation-enhancing effects of cocaine. To examine this, we trained male and female rats on a progressive ratio (PR) task for a food reinforcer. Each rat underwent a series of tests in which they were pretreated with cocaine alone or in combination with systemic or intra-VTA administration of the CB1 receptor antagonist rimonabant or the 2-AG synthesis inhibitor tetrahydrolipstatin (THL). Cocaine increased motivation, measured by augmented PR breakpoints, while rimonabant dose-dependently decreased motivation. Importantly, intra-VTA administration of rimonabant or THL, at doses that did not decrease breakpoints on their own, blocked systemic cocaine administration from increasing breakpoints in male and female rats. These data suggest that cocaine-induced increases in motivation require 2-AG signaling at CB1 receptors in the VTA and may provide critical insight into cannabinoid-based pharmacotherapeutic targets for the successful treatment of substance abuse.
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Affiliation(s)
- Sheila A Engi
- Dept. of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA; Dept. of Pharmacology, Universidade Federal de São Paulo - UNIFESP, São Paulo, SP, Brazil
| | - Erin J Beebe
- Dept. of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Victoria M Ayvazian
- Dept. of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Fabio C Cruz
- Dept. of Pharmacology, Universidade Federal de São Paulo - UNIFESP, São Paulo, SP, Brazil
| | - Joseph F Cheer
- Dept. of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA; Dept. of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Jennifer M Wenzel
- Dept. of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Natalie E Zlebnik
- Dept. of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA.
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21
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Oleson EB, Hamilton LR, Gomez DM. Cannabinoid Modulation of Dopamine Release During Motivation, Periodic Reinforcement, Exploratory Behavior, Habit Formation, and Attention. Front Synaptic Neurosci 2021; 13:660218. [PMID: 34177546 PMCID: PMC8222827 DOI: 10.3389/fnsyn.2021.660218] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 05/05/2021] [Indexed: 12/12/2022] Open
Abstract
Motivational and attentional processes energize action sequences to facilitate evolutionary competition and promote behavioral fitness. Decades of neuropharmacology, electrophysiology and electrochemistry research indicate that the mesocorticolimbic DA pathway modulates both motivation and attention. More recently, it was realized that mesocorticolimbic DA function is tightly regulated by the brain's endocannabinoid system and greatly influenced by exogenous cannabinoids-which have been harnessed by humanity for medicinal, ritualistic, and recreational uses for 12,000 years. Exogenous cannabinoids, like the primary psychoactive component of cannabis, delta-9-tetrahydrocannabinol, produce their effects by acting at binding sites for naturally occurring endocannabinoids. The brain's endocannabinoid system consists of two G-protein coupled receptors, endogenous lipid ligands for these receptor targets, and several synthetic and metabolic enzymes involved in their production and degradation. Emerging evidence indicates that the endocannabinoid 2-arachidonoylglycerol is necessary to observe concurrent increases in DA release and motivated behavior. And the historical pharmacology literature indicates a role for cannabinoid signaling in both motivational and attentional processes. While both types of behaviors have been scrutinized under manipulation by either DA or cannabinoid agents, there is considerably less insight into prospective interactions between these two important signaling systems. This review attempts to summate the relevance of cannabinoid modulation of DA release during operant tasks designed to investigate either motivational or attentional control of behavior. We first describe how cannabinoids influence DA release and goal-directed action under a variety of reinforcement contingencies. Then we consider the role that endocannabinoids might play in switching an animal's motivation from a goal-directed action to the search for an alternative outcome, in addition to the formation of long-term habits. Finally, dissociable features of attentional behavior using both the 5-choice serial reaction time task and the attentional set-shifting task are discussed along with their distinct influences by DA and cannabinoids. We end with discussing potential targets for further research regarding DA-cannabinoid interactions within key substrates involved in motivation and attention.
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Affiliation(s)
- Erik B. Oleson
- Department of Psychology, University of Colorado Denver, Denver, CO, United States
| | - Lindsey R. Hamilton
- Department of Psychology, University of Colorado Denver, Denver, CO, United States
| | - Devan M. Gomez
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, United States
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22
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Hoffman AF, Hwang EK, Lupica CR. Impairment of Synaptic Plasticity by Cannabis, Δ 9-THC, and Synthetic Cannabinoids. Cold Spring Harb Perspect Med 2021; 11:cshperspect.a039743. [PMID: 32341064 PMCID: PMC8091957 DOI: 10.1101/cshperspect.a039743] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The ability of neurons to dynamically and flexibly encode synaptic inputs via short- and long-term plasticity is critical to an organism's ability to learn and adapt to the environment. Whereas synaptic plasticity may be encoded by pre- or postsynaptic mechanisms, current evidence suggests that optimization of learning requires both forms of plasticity. Endogenous cannabinoids (eCBs) play critical roles in modulating synaptic transmission via activation of cannabinoid CB1 receptors (CB1Rs) in many central nervous system (CNS) regions, and the eCB system has been implicated, either directly or indirectly, in several forms of synaptic plasticity. Because of this, perturbations within the eCB signaling system can lead to impairments in a variety of learned behaviors. One agent of altered eCB signaling is exposure to "exogenous cannabinoids" such as the primary psychoactive constituent of cannabis, Δ9-THC, or illicit synthetic cannabinoids that in many cases have higher potency and efficacy than Δ9-THC. Thus, by targeting the eCB system, these agonists can produce widespread impairment of synaptic plasticity by disrupting ongoing eCB function. Here, we review studies in which Δ9-THC and synthetic cannabinoids impair synaptic plasticity in a variety of neuronal circuits and examine evidence that this contributes to their well-documented ability to disrupt cognition and behavior.
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Affiliation(s)
- Alexander F Hoffman
- Electrophysiology Research Section, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224, USA
| | - Eun-Kyung Hwang
- Electrophysiology Research Section, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224, USA
| | - Carl R Lupica
- Electrophysiology Research Section, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224, USA
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23
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Zhang H, Lipinski AA, Liktor-Busa E, Smith AF, Moutal A, Khanna R, Langlais PR, Largent-Milnes TM, Vanderah TW. The Effects of Repeated Morphine Treatment on the Endogenous Cannabinoid System in the Ventral Tegmental Area. Front Pharmacol 2021; 12:632757. [PMID: 33953672 PMCID: PMC8090348 DOI: 10.3389/fphar.2021.632757] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 02/26/2021] [Indexed: 12/18/2022] Open
Abstract
The therapeutic utility of opioids is diminished by their ability to induce rewarding behaviors that may lead to opioid use disorder. Recently, the endogenous cannabinoid system has emerged as a hot topic in the study of opioid reward but relatively little is known about how repeated opioid exposure may affect the endogenous cannabinoid system in the mesolimbic reward circuitry. In the present study, we investigated how sustained morphine may modulate the endogenous cannabinoid system in the ventral tegmental area (VTA) of Sprague Dawley rats, a critical region in the mesolimbic reward circuitry. Studies here using proteomic analysis and quantitative real-time PCR (qRT-PCR) found that the VTA expresses 32 different proteins or genes related to the endogenous cannabinoid system; three of these proteins or genes (PLCγ2, ABHD6, and CB2R) were significantly affected after repeated morphine exposure (CB2R was only detected by qRT-PCR but not proteomics). We also identified that repeated morphine treatment does not alter either anandamide (AEA) or 2-arachidonoylglycerol (2-AG) levels in the VTA compared to saline treatment; however, there may be diminished levels of anandamide (AEA) production in the VTA 4 h after a single morphine injection in both chronic saline and morphine pretreated cohorts. Treating the animals with an inhibitor of 2-AG degradation significantly decreased repeated opioid rewarding behavior. Taken together, our studies reveal a potential influence of sustained opioids on the endocannabinoid system in the VTA, suggesting that the endogenous cannabinoid system may participate in the opioid-induced reward.
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Affiliation(s)
- Hong Zhang
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States
| | - Austin A. Lipinski
- Department of Medicine, Division of Endocrinology, College of Medicine, University of Arizona, Tucson, AZ, United States
| | - Erika Liktor-Busa
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States
| | - Angela F. Smith
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States
| | - Aubin Moutal
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States
| | - Rajesh Khanna
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States
| | - Paul R. Langlais
- Department of Medicine, Division of Endocrinology, College of Medicine, University of Arizona, Tucson, AZ, United States
| | - Tally M. Largent-Milnes
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States
| | - Todd W. Vanderah
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States
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24
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Laksmidewi AAAP, Soejitno A. Endocannabinoid and dopaminergic system: the pas de deux underlying human motivation and behaviors. J Neural Transm (Vienna) 2021; 128:615-630. [PMID: 33712975 PMCID: PMC8105194 DOI: 10.1007/s00702-021-02326-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 03/04/2021] [Indexed: 01/11/2023]
Abstract
Endocannabinoid system (ECS) has been identified ever since cannabinoid, an active substance of Cannabis, was known to interact with endogenous cannabinoid (endocannabinoid/eCB) receptors. It later turned out that eCB was more intricate than previously thought. It has a pervasive role and exerts a multitude of cellular signaling mechanisms, regulating various physiological neurotransmission pathways in the human brain, including the dopaminergic (DA) system. eCB roles toward DA system were robust, clearly delineated, and reproducible with respect to physiological as well as pathological neurochemical and neurobehavioral manifestations of DA system, particularly those involving the nigrostriatal and mesocorticolimbic pathways. The eCB–DA system regulates the basics in the Maslow’s pyramid of hierarchy of needs required for individual survival such as food and sexual activity for reproductive purpose to those of higher needs in the pyramid, including self-actualization behaviors leading to achievement and reward (e.g., academic- and/or work-related performance and achievements). It is, thus, interesting to specifically discuss the eCB–DA system, not only on the molecular level, but also its tremendous potential to be developed as a future therapeutic strategy for various neuropsychiatric problems, including obesity, drug addiction and withdrawal, pathological hypersexuality, or low motivation behaviors.
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Affiliation(s)
- A A A Putri Laksmidewi
- Neurobehavioral and Cognitive Division, Neurology Department, Faculty of Medicine, Udayana University/Sanglah Hospital, Denpasar, Bali, Indonesia.
| | - Andreas Soejitno
- Neurobehavioral and Cognitive Division, Neurology Department, Faculty of Medicine, Udayana University/Sanglah Hospital, Denpasar, Bali, Indonesia
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25
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Ney LJ, Akhurst J, Bruno R, Laing PAF, Matthews A, Felmingham KL. Dopamine, endocannabinoids and their interaction in fear extinction and negative affect in PTSD. Prog Neuropsychopharmacol Biol Psychiatry 2021; 105:110118. [PMID: 32991952 DOI: 10.1016/j.pnpbp.2020.110118] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 09/03/2020] [Accepted: 09/22/2020] [Indexed: 12/13/2022]
Abstract
There currently exist few frameworks for common neurobiology between reexperiencing and negative cognitions and mood symptoms of PTSD. Adopting a dopaminergic framework for PTSD unites many aspects of unique symptom clusters, and this approach also links PTSD symptomology to common comorbidities with a common neurobiological deficiency. Here we review the dopamine literature and incorporate it with a growing field of research that describes both the contribution of endocannabinoids to fear extinction and PTSD, as well as the interactions between dopaminergic and endocannabinoid systems underlying this disorder. Based on current evidence, we outline an early, preliminary model that links re-experiencing and negative cognitions and mood in PTSD by invoking the interaction between endocannabinoid and dopaminergic signalling in the brain. These interactions between PTSD, dopamine and endocannabinoids may have implications for future therapies for treatment-resistant and comorbid PTSD patients.
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Affiliation(s)
- Luke J Ney
- School of Psychology, University of Tasmania, Australia.
| | - Jane Akhurst
- School of Psychology, University of Tasmania, Australia
| | | | - Patrick A F Laing
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne & Melbourne Health, Australia
| | | | - Kim L Felmingham
- School of Psychological Sciences, University of Melbourne, Australia
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26
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Tian W, Chen S. Neurotransmitters, Cell Types, and Circuit Mechanisms of Motor Skill Learning and Clinical Applications. Front Neurol 2021; 12:616820. [PMID: 33716924 PMCID: PMC7947691 DOI: 10.3389/fneur.2021.616820] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 01/18/2021] [Indexed: 02/02/2023] Open
Abstract
Animals acquire motor skills to better survive and adapt to a changing environment. The ability to learn novel motor actions without disturbing learned ones is essential to maintaining a broad motor repertoire. During motor learning, the brain makes a series of adjustments to build novel sensory–motor relationships that are stored within specific circuits for long-term retention. The neural mechanism of learning novel motor actions and transforming them into long-term memory still remains unclear. Here we review the latest findings with regard to the contributions of various brain subregions, cell types, and neurotransmitters to motor learning. Aiming to seek therapeutic strategies to restore the motor memory in relative neurodegenerative disorders, we also briefly describe the common experimental tests and manipulations for motor memory in rodents.
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Affiliation(s)
- Wotu Tian
- Department of Neurology and Institute of Neurology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shengdi Chen
- Department of Neurology and Institute of Neurology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
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27
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Tunisi L, D'Angelo L, Fernández-Rilo AC, Forte N, Piscitelli F, Imperatore R, de Girolamo P, Di Marzo V, Cristino L. Orexin-A/Hypocretin-1 Controls the VTA-NAc Mesolimbic Pathway via Endocannabinoid-Mediated Disinhibition of Dopaminergic Neurons in Obese Mice. Front Synaptic Neurosci 2021; 13:622405. [PMID: 33613258 PMCID: PMC7890184 DOI: 10.3389/fnsyn.2021.622405] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/11/2021] [Indexed: 01/27/2023] Open
Abstract
Disinhibition of orexin-A/hypocretin-1 (OX-A) release occurs to several output areas of the lateral hypothalamus (LH) in the brain of leptin knockout obese ob/ob mice. In this study, we have investigated whether a similar increase of OX-A release occurs to the ventral tegmental area (VTA), an orexinergic LH output area with functional effects on dopaminergic signaling at the mesolimbic circuit. By confocal and correlative light and electron microscopy (CLEM) morphological studies coupled to molecular, biochemical, and pharmacological approaches, we investigated OX-A-mediated dopaminergic signaling at the LH-VTA-nucleus accumbens (NAc) pathway in obese ob/ob mice compared to wild-type (wt) lean littermates. We found an elevation of OX-A trafficking and release to the VTA of ob/ob mice and consequent orexin receptor-1 (OX1R)-mediated over-activation of dopaminergic (DA) neurons via phospholipase C (PLC)/diacylglycerol lipase (DAGL-α)-induced biosynthesis of the endocannabinoid 2-arachidonoylglycerol (2-AG). In fact, by retrograde signaling to cannabinoid receptor type 1 (CB1R) at inhibitory inputs to DA neurons, 2-AG inhibited GABA release thus inducing an increase in DA concentration in the VTA and NAc of ob/ob mice. This effect was prevented by the OX1R antagonist SB-334867 (30 mg/Kg, i.p.), or the CB1R antagonist AM251 (10 mg/Kg, i.p.) and mimicked by OX-A injection (40 μg/Kg, i.p.) in wt lean mice. Enhanced DA signaling to the NAc in ob/ob mice, or in OX-A-injected wt mice, was accompanied by β-arrestin2-mediated desensitization of dopamine D2 receptor (D2R) in a manner prevented by SB-334867 or the D2R antagonist L741 (1.5 mg/Kg, i.p.). These results further support the role of OX-A signaling in the control of neuroadaptive responses, such as compulsive reward-seeking behavior or binge-like consumption of high palatable food, and suggest that aberrant OX-A trafficking to the DA neurons in the VTA of ob/ob mice influences the D2R response at NAc, a main target area of the mesolimbic pathway, via 2-AG/CB1-mediated retrograde signaling.
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Affiliation(s)
- Lea Tunisi
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, National Research Council, Pozzuoli, Italy.,Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Naples, Italy
| | - Livia D'Angelo
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Naples, Italy
| | - Alba Clara Fernández-Rilo
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, National Research Council, Pozzuoli, Italy
| | - Nicola Forte
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, National Research Council, Pozzuoli, Italy.,Canada Excellence Research Chair on the Microbiome-Endocannabinoidome Axis in Metabolic Health, Université Laval, Québec City, QC, Canada
| | - Fabiana Piscitelli
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, National Research Council, Pozzuoli, Italy
| | - Roberta Imperatore
- Department of Sciences and Technologies, University of Sannio, Benevento, Italy
| | - Paolo de Girolamo
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Naples, Italy
| | - Vincenzo Di Marzo
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, National Research Council, Pozzuoli, Italy.,Canada Excellence Research Chair on the Microbiome-Endocannabinoidome Axis in Metabolic Health, Université Laval, Québec City, QC, Canada.,Heart and Lung Research Institute of Université Laval, and Institute for Nutrition and Functional Foods, Université Laval, Québec City, QC, Canada
| | - Luigia Cristino
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, National Research Council, Pozzuoli, Italy
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28
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Everett TJ, Gomez DM, Hamilton LR, Oleson EB. Endocannabinoid modulation of dopamine release during reward seeking, interval timing, and avoidance. Prog Neuropsychopharmacol Biol Psychiatry 2021; 104:110031. [PMID: 32663486 DOI: 10.1016/j.pnpbp.2020.110031] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 06/15/2020] [Accepted: 06/28/2020] [Indexed: 01/02/2023]
Abstract
Endocannabinoids (eCBs) are neuromodulators that influence a wide range of neural systems and behaviors. In the current review, we describe our recent research showing how eCBs, particularly 2-arachidonoylglycerol (2-AG), concurrently shape mesolimbic dopamine (DA) release and associated behavior. We will restrict our discussion by emphasizing three distinct behaviors: reward seeking, interval timing, and active avoidance. During reward seeking we find that 2-AG is necessary to observe cue-evoked DA release events that are thought to represent the value of a rewarding outcome. We then describe data showing that 2-AG modulates unique patterns of DA release and behavior observed under conditions of periodic reinforcement. These data are discussed within the context of interval timing and adjunctive behavior. eCB modulation of DA release is also implicated in defensive behavior, including the avoidance of harm. As in reward seeking, our data suggest that the concentration of DA that is evoked by a warning signal can represent the value of an avoidance outcome. And, disrupting eCB signaling concomitantly reduces the concentration of the avoidance value signal and active avoidance. Disruptions in reward seeking, interval timing, and defensive behavior are commonly observed in a variety of movement disorders (e.g., Parkinson's and Huntington's disease) and disorders of motivation (e.g., addiction). We believe our data on eCB-DA interactions have implications for the development of novel pharmacotherapies to treat these disorders. Thus, we conclude by discussing how eCB pharmacology might be harnessed to treat disorders of movement and motivation.
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Affiliation(s)
| | - Devan M Gomez
- Psychology Department, University of Colorado Denver, USA; Department of Biomedical Sciences, Marquette University, USA
| | | | - Erik B Oleson
- Psychology Department, University of Colorado Denver, USA; Integrative Biology Department, University of Colorado Denver, USA.
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29
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Gomez DM, Everett TJ, Hamilton LR, Ranganath A, Cheer JF, Oleson EB. Chronic cannabinoid exposure produces tolerance to the dopamine releasing effects of WIN 55,212-2 and heroin in adult male rats. Neuropharmacology 2021; 182:108374. [PMID: 33115642 PMCID: PMC7836093 DOI: 10.1016/j.neuropharm.2020.108374] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 10/16/2020] [Accepted: 10/24/2020] [Indexed: 02/06/2023]
Abstract
Synthetic cannabinoids were introduced into recreational drug culture in 2008 and quickly became one of the most commonly abused drugs in the United States. The neurobiological consequences resulting from synthetic cannabinoid repeated exposure remain poorly understood. It is possible that a blunted dopamine (DA) response may lead drug users to consume larger quantities to compensate for this form of neurochemical tolerance. Because the endogenous cannabinoid and opioid systems exhibit considerable cross-talk and cross-tolerance frequently develops following repeated exposure to either opioids or cannabinoids, there is interest in investigating whether a history of synthetic cannabinoid exposure influences the ability of heroin to increase DA release. To test the effects of chronic cannabinoid exposure on cannabinoid- and heroin-evoked DA release, male adult rats were treated with either vehicle or a synthetic cannabinoid (WIN55-212-2; WIN) using an intravenous (IV) dose escalation regimen (0.2-0.8 mg/kg IV over 9 treatments). As predicted, WIN-treated rats showed a rightward shift in the dose-response relationship across all behavioral/physiological measures when compared to vehicle-treated controls. Then, using fast-scan cyclic voltammetry to measure changes in the frequency of transient DA events in the nucleus accumbens shell of awake and freely-moving rats, it was observed that the DA releasing effects of both WIN and heroin were significantly reduced in male rats with a pharmacological history of cannabinoid exposure. These results demonstrate that repeated exposure to the synthetic cannabinoid WIN can produce tolerance to its DA releasing effects and cross-tolerance to the DA releasing effects of heroin.
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Affiliation(s)
- Devan M Gomez
- Psychology Department, University of Colorado Denver, USA; Current: Department of Biomedical Sciences, Marquette University, USA
| | | | | | - Ajit Ranganath
- Department of Neurobiology and Anatomy, University of Maryland Baltimore, USA
| | - Joseph F Cheer
- Department of Neurobiology and Anatomy, University of Maryland Baltimore, USA
| | - Erik B Oleson
- Psychology Department, University of Colorado Denver, USA; Biology Department, University of Colorado Denver, USA.
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30
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Oliver EE, Hughes EK, Puckett MK, Chen R, Lowther WT, Howlett AC. Cannabinoid Receptor Interacting Protein 1a (CRIP1a) in Health and Disease. Biomolecules 2020; 10:biom10121609. [PMID: 33261012 PMCID: PMC7761089 DOI: 10.3390/biom10121609] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 11/23/2020] [Accepted: 11/24/2020] [Indexed: 12/15/2022] Open
Abstract
Endocannabinoid signaling depends upon the CB1 and CB2 cannabinoid receptors, their endogenous ligands anandamide and 2-arachidonoylglycerol, and intracellular proteins that mediate responses via the C-terminal and other intracellular receptor domains. The CB1 receptor regulates and is regulated by associated G proteins predominantly of the Gi/o subtypes, β-arrestins 1 and 2, and the cannabinoid receptor-interacting protein 1a (CRIP1a). Evidence for a physiological role for CRIP1a is emerging as data regarding the cellular localization and function of CRIP1a are generated. Here we summarize the neuronal distribution and role of CRIP1a in endocannabinoid signaling, as well as discuss investigations linking CRIP1a to development, vision and hearing sensory systems, hippocampus and seizure regulation, and psychiatric disorders including schizophrenia. We also examine the genetic and epigenetic association of CRIP1a within a variety of cancer subtypes. This review provides evidence upon which to base future investigations on the function of CRIP1a in health and disease.
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Affiliation(s)
- Emily E. Oliver
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Medical Center Blvd, Winston-Salem, NC 20157, USA; (E.E.O.); (E.K.H.); (M.K.P.); (R.C.)
- Department of Biochemistry and Center for Structural Biology, Wake Forest School of Medicine, Winston-Salem, NC 20157, USA;
| | - Erin K. Hughes
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Medical Center Blvd, Winston-Salem, NC 20157, USA; (E.E.O.); (E.K.H.); (M.K.P.); (R.C.)
- Department of Biochemistry and Center for Structural Biology, Wake Forest School of Medicine, Winston-Salem, NC 20157, USA;
| | - Meaghan K. Puckett
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Medical Center Blvd, Winston-Salem, NC 20157, USA; (E.E.O.); (E.K.H.); (M.K.P.); (R.C.)
| | - Rong Chen
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Medical Center Blvd, Winston-Salem, NC 20157, USA; (E.E.O.); (E.K.H.); (M.K.P.); (R.C.)
| | - W. Todd Lowther
- Department of Biochemistry and Center for Structural Biology, Wake Forest School of Medicine, Winston-Salem, NC 20157, USA;
| | - Allyn C. Howlett
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Medical Center Blvd, Winston-Salem, NC 20157, USA; (E.E.O.); (E.K.H.); (M.K.P.); (R.C.)
- Correspondence: ; Tel.: +1-336-716-8545
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Ahmadian SM, Ghahremani P, Alaei H. Microinjection of a Dopamine-D1 Receptor Agonist into the Ventral Tegmental Area Reverses the Blocked Expression of Morphine Conditioned Place Preference by N-Methyl-D-Aspartate Receptor Antagonist. Adv Biomed Res 2020; 9:54. [PMID: 33457337 PMCID: PMC7792870 DOI: 10.4103/abr.abr_11_20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/17/2020] [Accepted: 04/22/2020] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND The release of dopamine (DA) in the posterior ventral tegmental area (pVTA) plays an important role in cue-related learning, reward, and relapse. On the other hand, studies have shown that the use of N-methyl-D-aspartate receptor (NMDAR) antagonist (AP5) inhibits the expression of morphine (5 mg/kg, s. c) conditioned place preference (CPP). In this study, we have tried to show the interaction effect of the DA stimulatory agents through D1-like receptor (D1R) agonist (SKF38393) and D2-like receptor (D2R) antagonist (eticlopride; through disinhibition) with NMDAR antagonist into the pVTA on the expression of morphine CPP. MATERIALS AND METHODS The SKF38393 and eticlopride, individually and simultaneously (in ineffective doses), were injected into the pVTA with the AP5 in rats, and animals were then placed in a CPP apparatus. RESULTS Concomitant administration of D1R agonist (4 μg/rat) with NMDAR antagonist (1 μg/rat) induced the expression of morphine CPP, but the administration of D2R antagonist with NMDAR antagonist was unaffected on the expression of morphine CPP. Furthermore, concomitant administration of ineffective doses of D1R agonist and D2R antagonist with NMDAR antagonist had no effect on the expression of morphine CPP. CONCLUSIONS The results showed using higher doses of D1R agonist with NMDAR antagonist could reverse the blocked expression of morphine CPP by NMDAR antagonists, while, the use of D2R antagonist with NMDAR antagonist could not. Therefore, presynaptic receptors such as D1R probably through releasing other stimulatory neurotransmitters can play a vital role in the expression of morphine CPP and cue-related learning.
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Affiliation(s)
- Seyed Mostafa Ahmadian
- Department of Physiology, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Parisa Ghahremani
- Department of Physiology, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Hojjatallah Alaei
- Department of Physiology, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
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32
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Pérez-Valenzuela EJ, Andrés Coke ME, Grace AA, Fuentealba Evans JA. Adolescent Exposure to WIN 55212-2 Render the Nigrostriatal Dopaminergic Pathway Activated During Adulthood. Int J Neuropsychopharmacol 2020; 23:626-637. [PMID: 32710782 PMCID: PMC7710918 DOI: 10.1093/ijnp/pyaa053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 07/08/2020] [Accepted: 07/22/2020] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND During adolescence, neuronal circuits exhibit plasticity in response to physiological changes and to adapt to environmental events. Nigrostriatal dopaminergic pathways are in constant flux during development. Evidence suggests a relationship between early use of cannabinoids and psychiatric disorders characterized by altered dopaminergic systems, such as schizophrenia and addiction. However, the impact of adolescent exposure to cannabinoids on nigrostriatal dopaminergic pathways in adulthood remains unclear. The aim of this research was to determine the effects of repeated activation of cannabinoid receptors during adolescence on dopaminergic activity of nigrostriatal pathways and the mechanisms underlying this impact during adulthood. METHODS Male Sprague-Dawley rats were treated with 1.2 mg/kg WIN 55212-2 daily from postnatal day 40 to 65. Then no-net flux microdialysis of dopamine in the dorsolateral striatum, electrophysiological recording of dopaminergic neuronal activity, and microdialysis measures of gamma-aminobutyric acid (GABA) and glutamate in substantia nigra par compacta were carried out during adulthood (postnatal days 72-78). RESULTS Repeated activation of cannabinoid receptors during adolescence increased the release of dopamine in dorsolateral striatum accompanied by increased population activity of dopamine neurons and decreased extracellular GABA levels in substantia nigra par compacta in adulthood. Furthermore, perfusion of bicuculline, a GABAa antagonist, into the ventral pallidum reversed the increased dopamine neuron population activity in substantia nigra par compacta induced by adolescent cannabinoid exposure. CONCLUSIONS These results suggest that adolescent exposure to cannabinoid agonists produces disinhibition of nigrostriatal dopamine transmission during adulthood mediated by decreased GABAergic input from the ventral pallidum.
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Affiliation(s)
- Enzo Javier Pérez-Valenzuela
- Department of Pharmacy and Interdisciplinary Center of Neuroscience, Faculty of Chemistry and Pharmacy, Pontificia Universidad Católica de Chile, Santiago, Chile,Departments of Neuroscience, Psychiatry, and Psychology, Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - María Estela Andrés Coke
- Department of Cellular and Molecular Biology, Faculty of Biological Science, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Anthony A Grace
- Departments of Neuroscience, Psychiatry, and Psychology, Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - José Antonio Fuentealba Evans
- Department of Pharmacy and Interdisciplinary Center of Neuroscience, Faculty of Chemistry and Pharmacy, Pontificia Universidad Católica de Chile, Santiago, Chile,Correspondence: José Antonio Fuentealba, PhD, Department of Pharmacy, Faculty of Chemistry and Pharmacy, Pontificia Universidad Católica de Chile, Santiago, Chile ()
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33
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Hossain MZ, Ando H, Unno S, Kitagawa J. Targeting Peripherally Restricted Cannabinoid Receptor 1, Cannabinoid Receptor 2, and Endocannabinoid-Degrading Enzymes for the Treatment of Neuropathic Pain Including Neuropathic Orofacial Pain. Int J Mol Sci 2020; 21:E1423. [PMID: 32093166 PMCID: PMC7073137 DOI: 10.3390/ijms21041423] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 02/06/2023] Open
Abstract
Neuropathic pain conditions including neuropathic orofacial pain (NOP) are difficult to treat. Contemporary therapeutic agents for neuropathic pain are often ineffective in relieving pain and are associated with various adverse effects. Finding new options for treating neuropathic pain is a major priority in pain-related research. Cannabinoid-based therapeutic strategies have emerged as promising new options. Cannabinoids mainly act on cannabinoid 1 (CB1) and 2 (CB2) receptors, and the former is widely distributed in the brain. The therapeutic significance of cannabinoids is masked by their adverse effects including sedation, motor impairment, addiction and cognitive impairment, which are thought to be mediated by CB1 receptors in the brain. Alternative approaches have been developed to overcome this problem by selectively targeting CB2 receptors, peripherally restricted CB1 receptors and endocannabinoids that may be locally synthesized on demand at sites where their actions are pertinent. Many preclinical studies have reported that these strategies are effective for treating neuropathic pain and produce no or minimal side effects. Recently, we observed that inhibition of degradation of a major endocannabinoid, 2-arachydonoylglycerol, can attenuate NOP following trigeminal nerve injury in mice. This review will discuss the above-mentioned alternative approaches that show potential for treating neuropathic pain including NOP.
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Affiliation(s)
- Mohammad Zakir Hossain
- Department of Oral Physiology, School of Dentistry, Matsumoto Dental University, 1780 Gobara Hirooka, Shiojiri, Nagano 399-0781, Japan; (S.U.); (J.K.)
| | - Hiroshi Ando
- Department of Biology, School of Dentistry, Matsumoto Dental University, 1780 Gobara, Hirooka, Shiojiri, Nagano 399-0781, Japan;
| | - Shumpei Unno
- Department of Oral Physiology, School of Dentistry, Matsumoto Dental University, 1780 Gobara Hirooka, Shiojiri, Nagano 399-0781, Japan; (S.U.); (J.K.)
| | - Junichi Kitagawa
- Department of Oral Physiology, School of Dentistry, Matsumoto Dental University, 1780 Gobara Hirooka, Shiojiri, Nagano 399-0781, Japan; (S.U.); (J.K.)
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Feja M, Leigh MPK, Baindur AN, McGraw JJ, Wakabayashi KT, Cravatt BF, Bass CE. The novel MAGL inhibitor MJN110 enhances responding to reward-predictive incentive cues by activation of CB1 receptors. Neuropharmacology 2020; 162:107814. [PMID: 31628934 PMCID: PMC6983961 DOI: 10.1016/j.neuropharm.2019.107814] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 10/14/2019] [Accepted: 10/14/2019] [Indexed: 11/17/2022]
Abstract
CB1 receptor antagonists disrupt operant responding for food and drug reinforcers, and cue-induced reinstatement of cocaine and heroin seeking. Conversely, enhancing endocannabinoid signaling, particularly 2-arachidonyl glycerol (2-AG), by inhibition of monoacyl glycerol lipase (MAGL), may facilitate some aspects of reward seeking. To determine how endocannabinoid signaling affects responding to reward-predictive cues, we employed an operant task that allows us to parse the incentive motivational properties of cues. Rats were required to nosepoke during an intermittent audiovisual incentive cue (IC) to obtain a 10% sucrose reward. The CB1 receptor antagonist, rimonabant, dose-dependently decreased the response ratio (rewarded ICs/total presented) and active nosepokes per IC, while it increased the latency to respond to the cue and obtain the reward, indicating an overall decrease in both the choice and vigor of responding. Yet rats persisted in entering the reward cup. Using a modified version of the task, the novel MAGL inhibitor MJN110 increased the response ratio, decreased the latencies to respond to the IC and enhanced active nosepokes per IC, indicating a facilitation of cue-induced reward seeking. These effects were blocked by a subthreshold dose of rimonabant. Finally, MJN110 did not alter consumption of freely available sucrose within volumes obtained in the operant task. Together these data demonstrate blocking endocannabinoid tone at the CB1 receptor attenuates the ability of cues to induce reward seeking, while some aspects of motivation for the reward are retained. Conversely, enhancing 2-AG signaling at CB1 receptors facilitates IC responding and increases the motivational properties of the IC.
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Affiliation(s)
- Malte Feja
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, 955 Main St, Buffalo, NY, 14203, USA.
| | - Martin P K Leigh
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, 955 Main St, Buffalo, NY, 14203, USA.
| | - Ajay N Baindur
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, 955 Main St, Buffalo, NY, 14203, USA.
| | - Justin J McGraw
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, 955 Main St, Buffalo, NY, 14203, USA.
| | - Ken T Wakabayashi
- Department of Psychology, University of Nebraska-Lincoln, 1220 T. Street, Lincoln, NE, 68503, USA.
| | - Benjamin F Cravatt
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA.
| | - Caroline E Bass
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, 955 Main St, Buffalo, NY, 14203, USA.
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35
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Cannabinoids and the expanded endocannabinoid system in neurological disorders. Nat Rev Neurol 2019; 16:9-29. [DOI: 10.1038/s41582-019-0284-z] [Citation(s) in RCA: 320] [Impact Index Per Article: 64.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/15/2019] [Indexed: 12/13/2022]
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36
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Frau R, Miczán V, Traccis F, Aroni S, Pongor CI, Saba P, Serra V, Sagheddu C, Fanni S, Congiu M, Devoto P, Cheer JF, Katona I, Melis M. Prenatal THC exposure produces a hyperdopaminergic phenotype rescued by pregnenolone. Nat Neurosci 2019; 22:1975-1985. [PMID: 31611707 PMCID: PMC6884689 DOI: 10.1038/s41593-019-0512-2] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 09/11/2019] [Indexed: 12/21/2022]
Abstract
Increased legal availability of cannabis has led to a common misconception that it is a safe natural remedy for, amongst others, pregnancy-related ailments like morning sickness. Emerging clinical evidence, however, indicates that prenatal cannabis exposure (PCE) predisposes offspring to various neuropsychiatric disorders linked to aberrant dopaminergic function. Yet, our knowledge of how cannabis exposure affects the maturation of this neuromodulatory system remains limited. Here, we show that male, but not female, offspring of Δ9-tetrahydrocannabinol (THC)-exposed dams, a rat PCE model, exhibit extensive molecular and synaptic changes in dopaminergic neurons of the ventral tegmental area, including altered excitatory-to-inhibitory balance and switched polarity of long-term synaptic plasticity. The resulting hyperdopaminergic state leads to increased behavioral sensitivity to acute THC during pre-adolescence. The FDA-approved neurosteroid pregnenolone rescues synaptic defects and normalizes dopaminergic activity and behavior in PCE offspring, suggesting a therapeutic approach for offspring exposed to cannabis during pregnancy.
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Affiliation(s)
- Roberto Frau
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria, Monserrato, Italy
| | - Vivien Miczán
- Momentum Laboratory of Molecular Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.,Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
| | - Francesco Traccis
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria, Monserrato, Italy
| | - Sonia Aroni
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria, Monserrato, Italy.,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Csaba I Pongor
- Nikon Center of Excellence for Neuronal Imaging, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Pierluigi Saba
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria, Monserrato, Italy
| | - Valeria Serra
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria, Monserrato, Italy
| | - Claudia Sagheddu
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria, Monserrato, Italy
| | - Silvia Fanni
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria, Monserrato, Italy
| | - Mauro Congiu
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria, Monserrato, Italy
| | - Paola Devoto
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria, Monserrato, Italy
| | - Joseph F Cheer
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - István Katona
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
| | - Miriam Melis
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria, Monserrato, Italy.
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37
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Nakamura Y, Dryanovski DI, Kimura Y, Jackson SN, Woods AS, Yasui Y, Tsai SY, Patel S, Covey DP, Su TP, Lupica CR. Cocaine-induced endocannabinoid signaling mediated by sigma-1 receptors and extracellular vesicle secretion. eLife 2019; 8:e47209. [PMID: 31596232 PMCID: PMC6850780 DOI: 10.7554/elife.47209] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 10/03/2019] [Indexed: 12/24/2022] Open
Abstract
Cocaine is an addictive drug that acts in brain reward areas. Recent evidence suggests that cocaine stimulates synthesis of the endocannabinoid 2-arachidonoylglycerol (2-AG) in midbrain, increasing dopamine neuron activity via disinhibition. Although a mechanism for cocaine-stimulated 2-AG synthesis is known, our understanding of 2-AG release is limited. In NG108 cells and mouse midbrain tissue, we find that 2-AG is localized in non-synaptic extracellular vesicles (EVs) that are secreted in the presence of cocaine via interaction with the chaperone protein sigma-1 receptor (Sig-1R). The release of EVs occurs when cocaine causes dissociation of the Sig-1R from ADP-ribosylation factor (ARF6), a G-protein regulating EV trafficking, leading to activation of myosin light chain kinase (MLCK). Blockade of Sig-1R function, or inhibition of ARF6 or MLCK also prevented cocaine-induced EV release and cocaine-stimulated 2-AG-modulation of inhibitory synapses in DA neurons. Our results implicate the Sig-1R-ARF6 complex in control of EV release and demonstrate that cocaine-mediated 2-AG release can occur via EVs.
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Affiliation(s)
- Yoki Nakamura
- Cellular Pathobiology Section, Intramural Research ProgramNational Institute on Drug Abuse, National Institutes of HealthBaltimoreUnited States
| | - Dilyan I Dryanovski
- Electrophysiology Research Section, Intramural Research ProgramNational Institute on Drug Abuse, National Institutes of HealthBaltimoreUnited States
| | - Yuriko Kimura
- Cellular Pathobiology Section, Intramural Research ProgramNational Institute on Drug Abuse, National Institutes of HealthBaltimoreUnited States
| | - Shelley N Jackson
- Structural Biology Unit, Intramural Research ProgramNational Institute on Drug Abuse, National Institutes of HealthBaltimoreUnited States
| | - Amina S Woods
- Structural Biology Unit, Intramural Research ProgramNational Institute on Drug Abuse, National Institutes of HealthBaltimoreUnited States
| | - Yuko Yasui
- Cellular Pathobiology Section, Intramural Research ProgramNational Institute on Drug Abuse, National Institutes of HealthBaltimoreUnited States
| | - Shang-Yi Tsai
- Cellular Pathobiology Section, Intramural Research ProgramNational Institute on Drug Abuse, National Institutes of HealthBaltimoreUnited States
| | - Sachin Patel
- Cellular Pathobiology Section, Intramural Research ProgramNational Institute on Drug Abuse, National Institutes of HealthBaltimoreUnited States
- Department of Psychiatry and Behavioral Sciences, Vanderbilt Brain InstituteVanderbilt University Medical Center, Vanderbilt UniversityNashvilleUnited States
| | - Daniel P Covey
- Department of Anatomy and NeurobiologyUniversity of Maryland School of MedicineBaltimoreUnited States
| | - Tsung-Ping Su
- Cellular Pathobiology Section, Intramural Research ProgramNational Institute on Drug Abuse, National Institutes of HealthBaltimoreUnited States
| | - Carl R Lupica
- Electrophysiology Research Section, Intramural Research ProgramNational Institute on Drug Abuse, National Institutes of HealthBaltimoreUnited States
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Kruse LC, Cao JK, Viray K, Stella N, Clark JJ. Voluntary oral consumption of Δ 9-tetrahydrocannabinol by adolescent rats impairs reward-predictive cue behaviors in adulthood. Neuropsychopharmacology 2019; 44:1406-1414. [PMID: 30965351 PMCID: PMC6785709 DOI: 10.1038/s41386-019-0387-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 03/13/2019] [Accepted: 04/03/2019] [Indexed: 12/21/2022]
Abstract
Few preclinical approaches are available to study the health impact of voluntary consumption of edibles containing the psychoactive drug Δ9-tetrahydrocannabinol (THC). We developed and validated such approach by measuring voluntary oral consumption of THC-containing gelatin by rats and used it to study if and how THC consumption during adolescence impacts adult behavior. We found that adolescent rats of both sexes consumed enough THC to trigger acute hypothermia, analgesic, and locomotor responses, and that 15 days of access to THC-gelatin in adolescence resulted in the down-regulation of cannabinoid 1 receptors (CB1Rs) in adulthood in a sex and brain area specific manner. Remarkably, THC consumption by adolescent male rats and not female rats led to impaired Pavlovian reward-predictive cue behaviors in adulthood consistent with a male-specific loss of CB1R-expressing vGlut-1 synaptic terminals in the ventral tegmental area (VTA). Thus, voluntary oral consumption of THC during adolescence is associated with sex-dependent behavioral impairment in adulthood.
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Affiliation(s)
- Lauren C. Kruse
- 0000000122986657grid.34477.33Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA USA
| | - Jessica K. Cao
- 0000000122986657grid.34477.33Department of Pharmacology, University of Washington, Seattle, WA USA
| | - Katie Viray
- 0000000122986657grid.34477.33Department of Pharmacology, University of Washington, Seattle, WA USA
| | - Nephi Stella
- 0000000122986657grid.34477.33Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA USA ,0000000122986657grid.34477.33Department of Pharmacology, University of Washington, Seattle, WA USA
| | - Jeremy J. Clark
- 0000000122986657grid.34477.33Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA USA
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Canseco-Alba A, Schanz N, Sanabria B, Zhao J, Lin Z, Liu QR, Onaivi ES. Behavioral effects of psychostimulants in mutant mice with cell-type specific deletion of CB2 cannabinoid receptors in dopamine neurons. Behav Brain Res 2019; 360:286-297. [PMID: 30508607 PMCID: PMC6327973 DOI: 10.1016/j.bbr.2018.11.043] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 11/15/2018] [Accepted: 11/29/2018] [Indexed: 12/26/2022]
Abstract
Activation of the endocannabinoid system modulate dopaminergic pathways that are involved in the effects of psychostimulants including amphetamine, cocaine, nicotine and other drugs of abuse. Genetic deletion or pharmacological activation of CB2 cannabinoid receptor is involved in the modulation of the effects of psychostimulants and their rewarding properties. Here we report on the behavioral effects of psychostimulants in DAT-Cnr2 conditional knockout (cKO) mice with selective deletion of type 2 cannabinoid receptors in dopamine neurons. There was enhanced psychostimulant induced hyperactivity in DAT-Cnr2 cKO mice, but the psychostimulant-induced sensitization was absent in DAT-Cnr2 cKO compared to the WT mice. Intriguingly, lower doses of amphetamine reduced locomotor activity of the DAT-Cnr2 cKO mice. While cocaine, amphetamine and methamphetamine produced robust conditioned place preference (CPP) in both DAT-Cnr2 cKO and WT mice, nicotine at the dose used induced CPP only in the WT but not in the DAT-Cn2 cKO mice. However, pre-treatment with the CB2R selective agonist JWH133, blocked cocaine and nicotine induced CPP in the WT mice. The deletion of CB2Rs in dopamine neurons modified the levels of tyrosine hydroxylase, and reduced the expression of dopamine transporter gene expression in DAT-Cnr2 cKO midbrain region. Taken together, our data suggest that CB2Rs play a role in the modulation of dopamine-related effects of psychostimulants and could be exploited as therapeutic target in psychostimulant addiction and other psychiatric disorders associated with dopamine dysregulation.
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Affiliation(s)
- Ana Canseco-Alba
- Department of Biology, William Paterson University, Wayne, NJ, 07470, USA
| | - Norman Schanz
- Department of Biology, William Paterson University, Wayne, NJ, 07470, USA
| | - Branden Sanabria
- Department of Biology, William Paterson University, Wayne, NJ, 07470, USA
| | - Juan Zhao
- Department of Psychiatry, Harvard Medical School, Psychiatric Neurogenomics, Division of Alcohol and Drug Abuse, and Mailman Neuroscience Research Center, McLean Hospital, Belmont, MA, USA
| | - Zhicheng Lin
- Department of Psychiatry, Harvard Medical School, Psychiatric Neurogenomics, Division of Alcohol and Drug Abuse, and Mailman Neuroscience Research Center, McLean Hospital, Belmont, MA, USA
| | - Qing-Rong Liu
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Emmanuel S Onaivi
- Department of Biology, William Paterson University, Wayne, NJ, 07470, USA.
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40
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Role of the endocannabinoid system in drug addiction. Biochem Pharmacol 2018; 157:108-121. [PMID: 30217570 DOI: 10.1016/j.bcp.2018.09.013] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 09/10/2018] [Indexed: 12/20/2022]
Abstract
Drug addiction is a chronic relapsing disorder that produces a dramaticglobal health burden worldwide. Not effective treatment of drug addiction is currently available probably due to the difficulties to find an appropriate target to manage this complex disease raising the needs for further identification of novel therapeutic approaches. The endocannabinoid system has been found to play a crucial role in the neurobiological substrate underlying drug addiction. Endocannabinoids and cannabinoid receptors are widely expressed in the main areas of the mesocorticolimbic system that participate in the initiation and maintenance of drug consumption and in the development of compulsion and loss of behavioral control occurring during drug addiction. The identification of the important role played by CB1 cannabinoid receptors in drug addiction encouraged the possible used of an early commercialized CB1 receptor antagonist for treating drug addiction. However, the incidence of serious psychiatric adverse events leaded to the sudden withdrawal from the market of this CB1 antagonist and all the research programs developed by pharmaceutical companies to obtain new CB1 antagonists were stopped. Currently, new research strategies are under development to target the endocannabinoid system for drug addiction avoiding these side effects, which include allosteric negative modulators of CB1 receptors and compounds targeting CB2 receptors. Recent studies showing the potential role of CB2 receptors in the addictive properties of different drugs of abuse have open a promising research opportunity to develop novel possible therapeutic approaches.
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41
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Lupica CR, Hoffman AF. Cannabinoid disruption of learning mechanisms involved in reward processing. ACTA ACUST UNITED AC 2018; 25:435-445. [PMID: 30115765 PMCID: PMC6097761 DOI: 10.1101/lm.046748.117] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 07/06/2018] [Indexed: 02/06/2023]
Abstract
The increasing use of cannabis, its derivatives, and synthetic cannabinoids for medicinal and recreational purposes has led to burgeoning interest in understanding the addictive potential of this class of molecules. It is estimated that ∼10% of marijuana users will eventually show signs of dependence on the drug, and the diagnosis of cannabis use disorder (CUD) is increasing in the United States. The molecule that sustains the use of cannabis is Δ9-tetrahydrocannabinol (Δ9-THC), and our knowledge of its effects, and those of other cannabinoids on brain function has expanded rapidly in the past two decades. Additionally, the identification of endogenous cannabinoid (endocannabinoid) systems in brain and their roles in physiology and behavior, demonstrate extensive involvement of these lipid signaling molecules in regulating CNS function. Here, we examine roles for endogenous cannabinoids in shaping synaptic activity in cortical and subcortical brain circuits, and we discuss mechanisms in which exogenous cannabinoids, such as Δ9-THC, interact with endocannabinoid systems to disrupt neuronal network oscillations. We then explore how perturbation of the interaction of this activity within brain reward circuits may lead to impaired learning. Finally, we propose that disruption of cellular plasticity mechanisms by exogenous cannabinoids in cortical and subcortical circuits may explain the difficulty in establishing viable cannabinoid self-administration models in animals.
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Affiliation(s)
- Carl R Lupica
- Electrophysiology Research Section, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224, USA
| | - Alexander F Hoffman
- Electrophysiology Research Section, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224, USA
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42
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Gorzkiewicz A, Szemraj J. Brain endocannabinoid signaling exhibits remarkable complexity. Brain Res Bull 2018; 142:33-46. [PMID: 29953913 DOI: 10.1016/j.brainresbull.2018.06.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 06/06/2018] [Accepted: 06/21/2018] [Indexed: 01/04/2023]
Abstract
The endocannabinoid (eCB) signaling system is one of the most extensive of the mammalian brain. Despite the involvement of only few specific ligands and receptors, the system encompasses a vast diversity of triggered mechanisms and driven effects. It mediates a wide range of phenomena, including the regulation of transmitter release, neural excitability, synaptic plasticity, impulse spread, long-term neuronal potentiation, neurogenesis, cell death, lineage segregation, cell migration, inflammation, oxidative stress, nociception and the sleep cycle. It is also known to be involved in the processes of learning and memory formation. This extensive scope of action is attained by combining numerous variables. In a properly functioning brain, the correlations of these variables are kept in a strictly controlled balance; however, this balance is disrupted in many pathological conditions. However, while this balance is known to be disrupted by drugs in the case of addicts, the stimuli and mechanisms influencing the neurodegenerating brain remain elusive. This review examines the multiple factors and phenomena affecting the eCB signaling system in the brain. It evaluates techniques of controlling the eCB system to identify the obstacles in their applications and highlights the crucial interdependent variables that may influence biomedical research outcomes.
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Affiliation(s)
- Anna Gorzkiewicz
- Medical University of Lodz, ul.Mazowiecka 6/8, 92-215, Lodz, Poland.
| | - Janusz Szemraj
- Medical University of Lodz, ul.Mazowiecka 6/8, 92-215, Lodz, Poland
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Coccurello R, Maccarrone M. Hedonic Eating and the "Delicious Circle": From Lipid-Derived Mediators to Brain Dopamine and Back. Front Neurosci 2018; 12:271. [PMID: 29740277 PMCID: PMC5928395 DOI: 10.3389/fnins.2018.00271] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 04/09/2018] [Indexed: 01/09/2023] Open
Abstract
Palatable food can be seductive and hedonic eating can become irresistible beyond hunger and negative consequences. This is witnessed by the subtle equilibrium between eating to provide energy intake for homeostatic functions, and reward-induced overeating. In recent years, considerable efforts have been devoted to study neural circuits, and to identify potential factors responsible for the derangement of homeostatic eating toward hedonic eating and addiction-like feeding behavior. Here, we examined recent literature on “old” and “new” players accountable for reward-induced overeating and possible liability to eating addiction. Thus, the role of midbrain dopamine is positioned at the intersection between selected hormonal signals involved in food reward information processing (namely, leptin, ghrelin, and insulin), and lipid-derived neural mediators such as endocannabinoids. The impact of high fat palatable food and dietary lipids on endocannabinoid formation is reviewed in its pathogenetic potential for the derangement of feeding homeostasis. Next, endocannabinoid signaling that regulates synaptic plasticity is discussed as a key mechanism acting both at hypothalamic and mesolimbic circuits, and affecting both dopamine function and interplay between leptin and ghrelin signaling. Outside the canonical hypothalamic feeding circuits involved in energy homeostasis and the notion of “feeding center,” we focused on lateral hypothalamus as neural substrate able to confront food-associated homeostatic information with food salience, motivation to eat, reward-seeking, and development of compulsive eating. Thus, the lateral hypothalamus-ventral tegmental area-nucleus accumbens neural circuitry is reexamined in order to interrogate the functional interplay between ghrelin, dopamine, orexin, and endocannabinoid signaling. We suggested a pivotal role for endocannabinoids in food reward processing within the lateral hypothalamus, and for orexin neurons to integrate endocrine signals with food reinforcement and hedonic eating. In addition, the role played by different stressors in the reinstatement of preference for palatable food and food-seeking behavior is also considered in the light of endocannabinoid production, activation of orexin receptors and disinhibition of dopamine neurons. Finally, type-1 cannabinoid receptor-dependent inhibition of GABA-ergic release and relapse to reward-associated stimuli is linked to ghrelin and orexin signaling in the lateral hypothalamus-ventral tegmental area-nucleus accumbens network to highlight its pathological potential for food addiction-like behavior.
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Affiliation(s)
- Roberto Coccurello
- Department of Biomedical Sciences, Institute of Cell Biology and Neurobiology, National Research Council, Rome, Italy.,Laboratory of Neurochemistry of Lipids, European Center for Brain Research (CERC), IRRCS Santa Lucia Foundation, Rome, Italy
| | - Mauro Maccarrone
- Laboratory of Neurochemistry of Lipids, European Center for Brain Research (CERC), IRRCS Santa Lucia Foundation, Rome, Italy.,Department of Medicine, Campus Bio-Medico University of Rome, Rome, Italy
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Xiao L, Priest MF, Kozorovitskiy Y. Oxytocin functions as a spatiotemporal filter for excitatory synaptic inputs to VTA dopamine neurons. eLife 2018; 7:33892. [PMID: 29676731 PMCID: PMC5910020 DOI: 10.7554/elife.33892] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 03/26/2018] [Indexed: 01/15/2023] Open
Abstract
The experience of rewarding or aversive stimuli is encoded by distinct afferents to dopamine (DA) neurons of the ventral tegmental area (VTA). Several neuromodulatory systems including oxytocin regulate DA neuron excitability and synaptic transmission that process socially meaningful stimuli. We and others have recently characterized oxytocinergic modulation of activity in mouse VTA DA neurons, but the mechanisms underlying oxytocinergic modulation of synaptic transmission in DA neurons remain poorly understood. Here, we find that oxytocin application or optogenetic release decrease excitatory synaptic transmission, via long lasting, presynaptic, endocannabinoid-dependent mechanisms. Oxytocin modulation of excitatory transmission alters the magnitude of short and long-term depression. We find that only some glutamatergic projections to DA neurons express CB1 receptors. Optogenetic stimulation of three major VTA inputs demonstrates that oxytocin modulation is limited to projections that show evidence of CB1R transcripts. Thus, oxytocin gates information flow into reward circuits in a temporally selective and pathway-specific manner. The mammalian brain contains millions of nerve cells or neurons that communicate with each other via a process called neurotransmission. To send a message to its neighbor, a neuron releases a chemical called a neurotransmitter into the space between the cells. The neurotransmitter then binds to receiver proteins on the target cell. Another group of chemicals, known as neuromodulators, regulate this process, adjusting the way that neurons respond to neurotransmitters. In doing so, they help regulate many types of behavior in mammals. The neuromodulator oxytocin, for example, has earned the nickname ‘the love hormone’ because it promotes social behavior and bonding. It does this in part by altering the activity of neurons in a brain region called the ventral tegmental area (VTA). These neurons produce the brain’s main reward signal, dopamine, which is itself a neuromodulator. But exactly how oxytocin affects the activity of dopamine-producing neurons is unclear. By recording from individual neurons in slices of mouse brain tissue, Xiao et al. show that oxytocin filters inputs to dopamine neurons in the VTA. It does this by making the dopamine neurons release another group of reward signals, known as endocannabinoids. These are the brain’s own version of the chemicals found inside cannabis plants. The endocannabinoids bind to neurons that provide input to the VTA dopamine neurons. Some of these input neurons normally activate the VTA by releasing a neurotransmitter called glutamate. However, the binding of endocannabinoids decreases their ability to do this, and thereby lowers the activation of the VTA dopamine neurons. But not all glutamate neurons are sensitive to endocannabinoids. Moreover, oxytocin affects glutamate neurons that fire repeatedly less than it affects those that fire only occasionally. Oxytocin thus acts as a filter. It allows certain inputs – those that are repeatedly active and those that are insensitive to endocannabinoids – to continue activating VTA dopamine neurons. At the same time, it weakens the influence of other inputs. Dopamine release in the VTA drives drug abuse and addiction. Understanding how oxytocin affects VTA neurons may thus open up new avenues for the treatment of addiction disorders.
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Affiliation(s)
- Lei Xiao
- Department of Neurobiology, Northwestern University, Evanston, United States
| | - Michael F Priest
- Department of Neurobiology, Northwestern University, Evanston, United States
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Wenzel JM, Oleson EB, Gove WN, Cole AB, Gyawali U, Dantrassy HM, Bluett RJ, Dryanovski DI, Stuber GD, Deisseroth K, Mathur BN, Patel S, Lupica CR, Cheer JF. Phasic Dopamine Signals in the Nucleus Accumbens that Cause Active Avoidance Require Endocannabinoid Mobilization in the Midbrain. Curr Biol 2018; 28:1392-1404.e5. [PMID: 29681476 DOI: 10.1016/j.cub.2018.03.037] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 03/12/2018] [Accepted: 03/15/2018] [Indexed: 11/17/2022]
Abstract
Phasic dopamine (DA) release accompanies approach toward appetitive cues. However, a role for DA in the active avoidance of negative events remains undetermined. Warning signals informing footshock avoidance are associated with accumbal DA release, whereas depression of DA is observed with unavoidable footshock. Here, we reveal a causal role of phasic DA in active avoidance learning; specifically, optogenetic activation of DA neurons facilitates avoidance, whereas optical inhibition of these cells attenuates it. Furthermore, stimulation of DA neurons during presentation of a fear-conditioned cue accelerates the extinction of a passive defensive behavior (i.e., freezing). Dopaminergic control of avoidance requires endocannabinoids (eCBs), as perturbing eCB signaling in the midbrain disrupts avoidance, which is rescued by optical stimulation of DA neurons. Interestingly, once the avoidance task is learned, neither DA nor eCB manipulations affect performance, suggesting that once acquisition occurs, expression of this behavior is subserved by other anatomical frameworks. Our findings establish an instrumental role for DA release in learning active responses to aversive stimuli and its control by eCB signaling.
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Affiliation(s)
- Jennifer M Wenzel
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Erik B Oleson
- Department of Psychology, University of Colorado, Denver, CO 80204, USA
| | - Willard N Gove
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Anthony B Cole
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Utsav Gyawali
- Department of Pharmacology, School of Medicine, University of Maryland, Baltimore, MD 21201, USA
| | - Hannah M Dantrassy
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Rebecca J Bluett
- Vanderbilt Brain Institute and Department of Psychiatry, Vanderbilt University, Nashville, TN 37235, USA
| | - Dilyan I Dryanovski
- Electrophysiology Research Section, Cellular Neurobiology Branch, National Institute on Drug Abuse, Intramural Research Program, NIH, Baltimore, MD 21224, USA
| | - Garret D Stuber
- Department of Psychiatry and Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA
| | - Karl Deisseroth
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Brian N Mathur
- Department of Pharmacology, School of Medicine, University of Maryland, Baltimore, MD 21201, USA
| | - Sachin Patel
- Vanderbilt Brain Institute and Department of Psychiatry, Vanderbilt University, Nashville, TN 37235, USA; Vanderbilt School of Medicine and Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37235, USA
| | - Carl R Lupica
- Electrophysiology Research Section, Cellular Neurobiology Branch, National Institute on Drug Abuse, Intramural Research Program, NIH, Baltimore, MD 21224, USA
| | - Joseph F Cheer
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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46
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Perdikaris P, Tsarouchi M, Fanarioti E, Natsaridis E, Mitsacos A, Giompres P. Long lasting effects of chronic WIN55,212-2 treatment on mesostriatal dopaminergic and cannabinoid systems in the rat brain. Neuropharmacology 2017; 129:1-15. [PMID: 29113897 DOI: 10.1016/j.neuropharm.2017.11.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 10/16/2017] [Accepted: 11/03/2017] [Indexed: 01/14/2023]
Abstract
Cannabinoid administration modulates dopamine transmission via an indirect, multisynaptic mechanism that includes the activation of cannabinoid type-1 receptor (CB1R). The present study evaluated in rodents, the effects of acute and chronic (20 days) WIN55,212-2 administration, a non-selective CB1R agonist, on dopamine uptake and synthesis in the mesolimbic and nigrostriatal dopaminergic pathways and associate them to its effects on the endocannabinoid system. The effect of spontaneous withdrawal, after different abstinence periods (7 days, 20 days), was also assessed. Acute and chronic administration of WIN55,212-2 decreased dopamine transporter (DAT) binding and mRNA levels, as well as tyrosine hydroxylase (TH) mRNA expression in the substantia nigra (SN) and ventral tegmental area (VTA). In the striatum, chronic WIN55,212-2 administration led to decreased protein expression of DAT and TH, whereas no alterations were observed after acute administration, suggesting a diminished dopamine uptake and synthesis after chronic agonist treatment. Furthermore, after chronic agonist treatment, we observed reduced CB1R binding and mRNA levels in SN and striatum, providing evidence for a possible regulatory role of the endocannabinoid system on dopaminergic function. Seven days after WIN55,212-2 cessation, we observed a rebound increase in mRNA, binding and total protein levels of DAT and TH in VTA, SN and striatum proposing the existence of a biphasic expression pattern, which was also observed in CB1R binding levels. Within the 20-day period of abstinence, TH mRNA and protein levels and CB1R binding levels remain increased. The above results indicate that chronic CB1R agonist treatment induces long-lasting control of the mesostriatal dopaminergic activity.
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Affiliation(s)
- Panagiotis Perdikaris
- Laboratory of Human and Animal Physiology, Department of Biology, University of Patras, Patras, Greece
| | - Martha Tsarouchi
- Laboratory of Human and Animal Physiology, Department of Biology, University of Patras, Patras, Greece
| | - Eleni Fanarioti
- Laboratory of Human and Animal Physiology, Department of Biology, University of Patras, Patras, Greece
| | - Evangelos Natsaridis
- Laboratory of Human and Animal Physiology, Department of Biology, University of Patras, Patras, Greece
| | - Ada Mitsacos
- Laboratory of Physiology, Department of Medicine, University of Patras, Patras, Greece
| | - Panagiotis Giompres
- Laboratory of Human and Animal Physiology, Department of Biology, University of Patras, Patras, Greece.
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CB1-Dependent Long-Term Depression in Ventral Tegmental Area GABA Neurons: A Novel Target for Marijuana. J Neurosci 2017; 37:10943-10954. [PMID: 29038246 DOI: 10.1523/jneurosci.0190-17.2017] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 09/05/2017] [Accepted: 09/10/2017] [Indexed: 01/13/2023] Open
Abstract
The VTA is necessary for reward behavior with dopamine cells critically involved in reward signaling. Dopamine cells in turn are innervated and regulated by neighboring inhibitory GABA cells. Using whole-cell electrophysiology in juvenile-adolescent GAD67-GFP male mice, we examined excitatory plasticity in fluorescent VTA GABA cells. A novel CB1-dependent LTD was induced in GABA cells that was dependent on metabotropic glutamate receptor 5, and cannabinoid receptor 1 (CB1). LTD was absent in CB1 knock-out mice but preserved in heterozygous littermates. Bath applied Δ9-tetrahydrocannabinol depressed GABA cell activity, therefore downstream dopamine cells will be disinhibited; and thus, this could potentially result in increased reward. Chronic injections of Δ9-tetrahydrocannabinol occluded LTD compared with vehicle injections; however, a single exposure was insufficient to do so. As synaptic modifications by drugs of abuse are often tied to addiction, these data suggest a possible mechanism for the addictive effects of Δ9-tetrahydrocannabinol in juvenile-adolescents, by potentially altering reward behavioral outcomes.SIGNIFICANCE STATEMENT The present study identifies a novel form of glutamatergic synaptic plasticity in VTA GABA neurons, a currently understudied cell type that is critical for the brain's reward circuit, and how Δ9-tetrahydrocannabinol occludes this plasticity. This study specifically addresses a potential unifying mechanism whereby marijuana could exert rewarding and addictive/withdrawal effects. Marijuana use and legalization are a pressing issue for many states in the United States. Although marijuana is the most commonly abused illicit drug, the implications of legalized, widespread, or continued usage are speculative. This study in juvenile-adolescent aged mice identifies a novel form of synaptic plasticity in VTA GABA cells, and the synaptic remodeling that can occur after Δ9-tetrahydrocannabinol use.
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Han X, He Y, Bi GH, Zhang HY, Song R, Liu QR, Egan JM, Gardner EL, Li J, Xi ZX. CB1 Receptor Activation on VgluT2-Expressing Glutamatergic Neurons Underlies Δ 9-Tetrahydrocannabinol (Δ 9-THC)-Induced Aversive Effects in Mice. Sci Rep 2017; 7:12315. [PMID: 28951549 PMCID: PMC5614984 DOI: 10.1038/s41598-017-12399-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 09/08/2017] [Indexed: 11/09/2022] Open
Abstract
Cannabis can be rewarding or aversive. Cannabis reward is believed to be mediated by activation of cannabinoid CB1 receptors (CB1Rs) on GABAergic neurons that disinhibit dopaminergic neurons in the ventral tegmental area (VTA). However, little is known about the mechanisms underlying cannabis aversion in rodents. In the present study, CB1Rs are found not only on VTA GABAergic neurons, but also on VTA glutamatergic neurons that express vesicular glutamate transporter 2 (VgluT2). We then used Cre-Loxp transgenic technology to selectively delete CB1Rs in VgluT2-expressing glutamatergic neurons (VgluT2-CB1−/−) and Cre-dependent viral vector to express light-sensitive channelrhodopsin-2 into VTA glutamatergic neurons. We found that photoactivation of VTA glutamatergic neurons produced robust intracranial self-stimulation (ICSS) behavior, which was dose-dependently blocked by DA receptor antagonists, but enhanced by cocaine. In contrast, Δ9-tetrahydrocannabinol (Δ9-THC), the major psychoactive component of cannabis, produced dose-dependent conditioned place aversion and a reduction in the above optical ICSS in VgluT2-cre control mice, but not in VgluT2-CB1−/− mice. These findings suggest that activation of CB1Rs in VgluT2-expressing glutamate neurons produces aversive effects that might explain why cannabinoid is not rewarding in rodents and might also account for individual differences in the hedonic effects of cannabis in humans.
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Affiliation(s)
- Xiao Han
- Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse, Baltimore, MD, 21224, USA.,Beijing Institute of Pharmacology and Toxicology, Beijing, 100850, China
| | - Yi He
- Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse, Baltimore, MD, 21224, USA
| | - Guo-Hua Bi
- Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse, Baltimore, MD, 21224, USA
| | - Hai-Ying Zhang
- Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse, Baltimore, MD, 21224, USA
| | - Rui Song
- Beijing Institute of Pharmacology and Toxicology, Beijing, 100850, China
| | - Qing-Rong Liu
- Laboratory of Clinical Investigation, Intramural Research Program, National Institute on Aging, Baltimore, MD, 21224, USA
| | - Josephine M Egan
- Laboratory of Clinical Investigation, Intramural Research Program, National Institute on Aging, Baltimore, MD, 21224, USA
| | - Eliot L Gardner
- Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse, Baltimore, MD, 21224, USA
| | - Jing Li
- Beijing Institute of Pharmacology and Toxicology, Beijing, 100850, China.
| | - Zheng-Xiong Xi
- Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse, Baltimore, MD, 21224, USA.
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Prenatal Ethanol Exposure Persistently Alters Endocannabinoid Signaling and Endocannabinoid-Mediated Excitatory Synaptic Plasticity in Ventral Tegmental Area Dopamine Neurons. J Neurosci 2017; 37:5798-5808. [PMID: 28476947 DOI: 10.1523/jneurosci.3894-16.2017] [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: 12/21/2016] [Revised: 03/15/2017] [Accepted: 04/05/2017] [Indexed: 01/02/2023] Open
Abstract
Prenatal ethanol exposure (PE) leads to increased addiction risk which could be mediated by enhanced excitatory synaptic strength in ventral tegmental area (VTA) dopamine (DA) neurons. Previous studies have shown that PE enhances excitatory synaptic strength by facilitating an anti-Hebbian form of long-term potentiation (LTP). In this study, we investigated the effect of PE on endocannabinoid-mediated long-term depression (eCB-LTD) in VTA DA neurons. Rats were exposed to moderate (3 g/kg/d) or high (6 g/kg/d) levels of ethanol during gestation. Whole-cell recordings were conducted in male offspring between 4 and 10 weeks old.We found that PE led to increased amphetamine self-administration. Both moderate and high levels of PE persistently reduced low-frequency stimulation-induced eCB-LTD. Furthermore, action potential-independent glutamate release was regulated by tonic eCB signaling in PE animals. Mechanistic studies for impaired eCB-LTD revealed that PE downregulated CB1 receptor function. Interestingly, eCB-LTD in PE animals was rescued by metabotropic glutamate receptor I activation, suggesting that PE did not impair the synthesis/release of eCBs. In contrast, eCB-LTD in PE animals was not rescued by increasing presynaptic activity, which actually led to LTP in PE animals, whereas LTD was still observed in controls. This result shows that the regulation of excitatory synaptic plasticity is fundamentally altered in PE animals. Together, PE leads to impaired eCB-LTD at the excitatory synapses of VTA DA neurons primarily due to CB1 receptor downregulation. This effect could contribute to enhanced LTP and the maintenance of augmented excitatory synaptic strength in VTA DA neurons and increased addiction risk after PE.SIGNIFICANCE STATEMENT Prenatal ethanol exposure (PE) is among many adverse developmental factors known to increase drug addiction risk. Increased excitatory synaptic strength in VTA DA neurons is a critical cellular mechanism for addiction risk. Our results show that PE persistently alters eCB signaling and impairs eCB-LTD at the excitatory synapses, an important synaptic plasticity that weakens synaptic strength. These effects combined with PE-induced anti-Hebbian long-term potentiation reported in a previous study could result in the maintenance of enhanced excitatory synaptic strength in VTA DA neurons, which in turn contributes to PE-induced increase in addiction risk. Our findings also suggest that restoring normal eCB signaling in VTA DA neurons could be a useful strategy for treating behavioral symptoms caused by PE.
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50
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Endocannabinoid modulation of dopamine neurotransmission. Neuropharmacology 2017; 124:52-61. [PMID: 28450060 DOI: 10.1016/j.neuropharm.2017.04.033] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 04/20/2017] [Accepted: 04/23/2017] [Indexed: 12/15/2022]
Abstract
Dopamine (DA) is a major catecholamine neurotransmitter in the mammalian brain that controls neural circuits involved in the cognitive, emotional, and motor aspects of goal-directed behavior. Accordingly, perturbations in DA neurotransmission play a central role in several neuropsychiatric disorders. Somewhat surprisingly given its prominent role in numerous behaviors, DA is released by a relatively small number of densely packed neurons originating in the midbrain. The dopaminergic midbrain innervates numerous brain regions where extracellular DA release and receptor binding promote short- and long-term changes in postsynaptic neuron function. Striatal forebrain nuclei receive the greatest proportion of DA projections and are a predominant hub at which DA influences behavior. A number of excitatory, inhibitory, and modulatory inputs orchestrate DA neurotransmission by controlling DA cell body firing patterns, terminal release, and effects on postsynaptic sites in the striatum. The endocannabinoid (eCB) system serves as an important filter of afferent input that acts locally at midbrain and terminal regions to shape how incoming information is conveyed onto DA neurons and to output targets. In this review, we aim to highlight existing knowledge regarding how eCB signaling controls DA neuron function through modifications in synaptic strength at midbrain and striatal sites, and to raise outstanding questions on this topic. This article is part of the Special Issue entitled "A New Dawn in Cannabinoid Neurobiology".
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