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Li S, He Y, Turner D, Wei N, Ma L, Taylor DH, Taylor DT, Ji X, Wu J. Electrophysiological Phenotypes of Hippocampal Synaptic and Network Functions in Cannabinoid Receptor 2 Knockout Mice. Cannabis Cannabinoid Res 2024. [PMID: 38502778 DOI: 10.1089/can.2023.0186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2024] Open
Abstract
Background: The cannabinoid receptor 2 (CB2R), a cannabinoid receptor primarily expressed in immune cells, has been found in the brain, particularly in the hippocampus, where it plays crucial roles in modulating various neural functions, including synaptic plasticity, neuroprotection, neurogenesis, anxiety and stress responses, and neuroinflammation. Despite this growing understanding, the intricate electrophysiological characteristics of hippocampal neurons in CB2R knockout (CB2R KO) mice remain elusive. Aim and Methods: This study aimed to comprehensively assess the electrophysiological traits of hippocampal synaptic and network functions in CB2R KO mice. The focus was on aspects such as synaptic transmission, short- and long-term synaptic plasticity, and neural network synchrony (theta oscillations). Results: Our findings unveiled multiple functional traits in these CB2R KO mice, notably elevated synaptic transmission in hippocampal CA1 neurons, decreased both synaptic short-term plasticity (paired-pulse facilitation) and long-term potentiation (LTP), and impaired neural network synchronization. Conclusion: In essence, this study yields insightful revelations about the influence of CB2Rs on hippocampal neural functions. By illuminating the electrophysiological modifications in CB2R KO mice, our research enriches the comprehension of CB2R involvement in hippocampal function. Such insights could hold implications for advancing our understanding of the neural mechanisms under the influence of CB2Rs within the brain.
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Affiliation(s)
- Shuangtao Li
- Brain Function and Disease Laboratory, Shantou University Medical College, Shantou, Guangdong, China
| | - Yongchang He
- Department of Neurobiology, Barrow Neurological Institute and St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
| | - Dharshaun Turner
- Department of Neurobiology, Barrow Neurological Institute and St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
| | - Naili Wei
- Department of Neurosurgery, First Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong, China
| | - Luyao Ma
- Department of Neurobiology, Barrow Neurological Institute and St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
| | - Devin H Taylor
- Department of Neurobiology, Barrow Neurological Institute and St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
- Department of Biology, Utah Valley University, Orem, Utah, USA
| | | | - Xiaoyu Ji
- Brain Function and Disease Laboratory, Shantou University Medical College, Shantou, Guangdong, China
- Department of Neurosurgery, First Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong, China
| | - Jie Wu
- Brain Function and Disease Laboratory, Shantou University Medical College, Shantou, Guangdong, China
- Department of Neurobiology, Barrow Neurological Institute and St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
- Department of Neurosurgery, First Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong, China
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Piscura MK, Henderson-Redmond AN, Barnes RC, Mitra S, Guindon J, Morgan DJ. Mechanisms of cannabinoid tolerance. Biochem Pharmacol 2023; 214:115665. [PMID: 37348821 PMCID: PMC10528043 DOI: 10.1016/j.bcp.2023.115665] [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: 04/03/2023] [Revised: 06/09/2023] [Accepted: 06/13/2023] [Indexed: 06/24/2023]
Abstract
Cannabis has been used recreationally and medically for centuries, yet research into understanding the mechanisms of its therapeutic effects has only recently garnered more attention. There is evidence to support the use of cannabinoids for the treatment of chronic pain, muscle spasticity, nausea and vomiting due to chemotherapy, improving weight gain in HIV-related cachexia, emesis, sleep disorders, managing symptoms in Tourette syndrome, and patient-reported muscle spasticity from multiple sclerosis. However, tolerance and the risk for cannabis use disorder are two significant disadvantages for cannabinoid-based therapies in humans. Recent work has revealed prominent sex differences in the acute response and tolerance to cannabinoids in both humans and animal models. This review will discuss evidence demonstrating cannabinoid tolerance in rodents, non-human primates, and humans and our current understanding of the neuroadaptations occurring at the cannabinoid type 1 receptor (CB1R) that are responsible tolerance. CB1R expression is downregulated in tolerant animals and humans while there is strong evidence of CB1R desensitization in cannabinoid tolerant rodent models. Throughout the review, critical knowledge gaps are indicated and discussed, such as the lack of a neuroimaging probe to assess CB1R desensitization in humans. The review discusses the intracellular signaling pathways that are responsible for mediating CB1R desensitization and downregulation including the action of G protein-coupled receptor kinases, β-arrestin2 recruitment, c-Jun N-terminal kinases, protein kinase A, and the intracellular trafficking of CB1R. Finally, the review discusses approaches to reduce cannabinoid tolerance in humans based on our current understanding of the neuroadaptations and mechanisms responsible for this process.
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Affiliation(s)
- Mary K Piscura
- Department of Biomedical Sciences, Marshall University, Huntington, WV 25755, USA; Department of Biomedical Sciences, Edward Via College of Osteopathic Medicine, Auburn, AL 36832, USA
| | | | - Robert C Barnes
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Swarup Mitra
- Department of Biomedical Sciences, Marshall University, Huntington, WV 25755, USA
| | - Josée Guindon
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Daniel J Morgan
- Department of Biomedical Sciences, Marshall University, Huntington, WV 25755, USA.
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Straiker A, Dvorakova M, Bosquez-Berger T, Blahos J, Mackie K. A collection of cannabinoid-related negative findings from autaptic hippocampal neurons. Sci Rep 2023; 13:9610. [PMID: 37311900 PMCID: PMC10264370 DOI: 10.1038/s41598-023-36710-3] [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: 10/13/2022] [Accepted: 06/08/2023] [Indexed: 06/15/2023] Open
Abstract
Autaptic hippocampal neurons are an architecturally simple model of neurotransmission that express several forms of cannabinoid signaling. Over the past twenty years this model has proven valuable for studies ranging from enzymatic control of endocannabinoid production and breakdown, to CB1 receptor structure/function, to CB2 signaling, understanding 'spice' (synthetic cannabinoid) pharmacology, and more. However, while studying cannabinoid signaling in these neurons, we have occasionally encountered what one might call 'interesting negatives', valid and informative findings in the context of our experimental design that, given the nature of scientific publishing, may not otherwise find their way into the scientific literature. In autaptic hippocampal neurons we have found that: (1) The fatty acid binding protein (FABP) blocker SBFI-26 does not alter CB1-mediated neuroplasticity. (2) 1-AG signals poorly relative to 2-AG in autaptic neurons. (3) Indomethacin is not a CB1 PAM in autaptic neurons. (4) The CB1-associated protein SGIP1a is not necessary for CB1 desensitization. We are presenting these negative or perplexing findings in the hope that they will prove beneficial to other laboratories and elicit fruitful discussions regarding their relevance and significance.
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Affiliation(s)
- Alex Straiker
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA.
| | - Michaela Dvorakova
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
| | - Taryn Bosquez-Berger
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
| | - Jaroslav Blahos
- Department of Molecular Pharmacology, Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, 142 20, Prague 4, Czech Republic
| | - Ken Mackie
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
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Grabon W, Rheims S, Smith J, Bodennec J, Belmeguenai A, Bezin L. CB2 receptor in the CNS: from immune and neuronal modulation to behavior. Neurosci Biobehav Rev 2023; 150:105226. [PMID: 37164044 DOI: 10.1016/j.neubiorev.2023.105226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 03/20/2023] [Accepted: 05/06/2023] [Indexed: 05/12/2023]
Abstract
Despite low levels of cannabinoid receptor type 2 (CB2R) expression in the central nervous system in human and rodents, a growing body of evidence shows CB2R involvement in many processes at the behavioral level, through both immune and neuronal modulations. Recent in vitro and in vivo evidence have highlighted the complex role of CB2R under physiological and inflammatory conditions. Under neuroinflammatory states, its activation seems to protect the brain and its functions, making it a promising target in a wide range of neurological disorders. Here, we provide a complete and updated overview of CB2R function in the central nervous system of rodents, spanning from modulation of immune function in microglia but also in other cell types, to behavior and neuronal activity, in both physiological and neuroinflammatory contexts.
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Affiliation(s)
- Wanda Grabon
- Université Claude Bernard Lyon 1, CNRS, Inserm, Centre de Recherche en Neurosciences de Lyon, U10208 UMR5292, TIGER Team - F-69500 Bron, France; Epilepsy Institute IDEE, 59 boulevard Pinel - F-69500 Bron, France.
| | - Sylvain Rheims
- Université Claude Bernard Lyon 1, CNRS, Inserm, Centre de Recherche en Neurosciences de Lyon, U10208 UMR5292, TIGER Team - F-69500 Bron, France; Epilepsy Institute IDEE, 59 boulevard Pinel - F-69500 Bron, France; Department of Functional Neurology and Epileptology, Hospices Civils de Lyon - France
| | - Jonathon Smith
- Université Claude Bernard Lyon 1, CNRS, Inserm, Centre de Recherche en Neurosciences de Lyon, U10208 UMR5292, TIGER Team - F-69500 Bron, France; Epilepsy Institute IDEE, 59 boulevard Pinel - F-69500 Bron, France
| | - Jacques Bodennec
- Université Claude Bernard Lyon 1, CNRS, Inserm, Centre de Recherche en Neurosciences de Lyon, U10208 UMR5292, TIGER Team - F-69500 Bron, France; Epilepsy Institute IDEE, 59 boulevard Pinel - F-69500 Bron, France
| | - Amor Belmeguenai
- Université Claude Bernard Lyon 1, CNRS, Inserm, Centre de Recherche en Neurosciences de Lyon, U10208 UMR5292, TIGER Team - F-69500 Bron, France; Epilepsy Institute IDEE, 59 boulevard Pinel - F-69500 Bron, France
| | - Laurent Bezin
- Université Claude Bernard Lyon 1, CNRS, Inserm, Centre de Recherche en Neurosciences de Lyon, U10208 UMR5292, TIGER Team - F-69500 Bron, France.
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Role of Cannabinoid CB2 Receptor in Alcohol Use Disorders: From Animal to Human Studies. Int J Mol Sci 2022; 23:ijms23115908. [PMID: 35682586 PMCID: PMC9180470 DOI: 10.3390/ijms23115908] [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: 04/14/2022] [Revised: 05/22/2022] [Accepted: 05/23/2022] [Indexed: 12/04/2022] Open
Abstract
Cumulative evidence has pointed out cannabinoid CB2 receptors (CB2r) as a potential therapeutic key target for treating alcohol use disorder (AUD). This review provides the most relevant results obtained from rodent and human studies, including an integrative section focused on the involvement of CB2r in the neurobiology of alcohol addiction. A literature search was conducted using the electronic databases Medline and Scopus for articles. The search strategy was as follows: “Receptor, Cannabinoid, CB2” AND “Alcohol-Related Disorders” AND “human/or patients”; “Receptor, Cannabinoid, CB2” AND “Alcohol” OR “Ethanol” AND “rodents/or mice/or rats”. Pharmacological approaches demonstrated that the activation or blockade of CB2r modulated different alcohol-addictive behaviors. Rodent models of alcoholism revealed significant alterations of CB2r in brain areas of the reward system. In addition, mice lacking CB2r (CB2KO) show increased alcohol consumption, motivation, and relapse alterations. It has been stressed that the potential neurobiological mechanisms underlying their behavioral effects involve critical elements of the alcohol reward system. Interestingly, recent postmortem studies showed CNR2 alterations in brain areas of alcoholic patients. Moreover, although the number of studies is limited, the results revealed an association between some genetic alterations of the CNR2 and an increased risk for developing AUD. This review provides evidence that CB2r may play a role in alcohol addiction. Clinical studies are necessary to figure out whether CB2r ligands may prove useful for the treatment of AUD in humans.
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Abidi AH, Alghamdi SS, Derefinko K. A critical review of cannabis in medicine and dentistry: A look back and the path forward. Clin Exp Dent Res 2022; 8:613-631. [PMID: 35362240 PMCID: PMC9209799 DOI: 10.1002/cre2.564] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 03/08/2022] [Accepted: 03/11/2022] [Indexed: 12/20/2022] Open
Abstract
Introduction In the last two decades, our understanding of the therapeutic utility and medicinal properties of cannabis has greatly changed. This change has been accompanied by widespread cannabis use in various communities and different age groups, especially within the United States. With this increase, we should consider the potential effects of cannabis–hemp on general public health and how they could alter therapeutic outcomes. Material and Methods The present investigation examined cannabis use for recreational and therapeutic use and a review of pertinent indexed literature was performed. The focused question evaluates “how cannabis or hemp products impact health parameters and do they provide potential therapeutic value in dentistry, and how do they interact with conventional medicines (drugs).” Indexed databases (PubMed/Medline, EMBASE) were searched without any time restrictions but language was restricted to English. Results The review highlights dental concerns of cannabis usage, the need to understand the endocannabinoid system (ECS), cannabinoid receptor system, its endogenous ligands, pharmacology, metabolism, current oral health, and medical dilemma to ascertain the detrimental or beneficial effects of using cannabis–hemp products. The pharmacological effects of pure cannabidiol (CBD) have been studied extensively while cannabis extracts can vary significantly and lack empirical studies. Several metabolic pathways are affected by cannabis use and could pose a potential drug interaction. The chronic use of cannabis is associated with health issues, but the therapeutic potential is multifold since there is a regulatory role of ECS in many pathologies. Conclusion Current shortcomings in understanding the benefits of cannabis or hemp products are limited due to pharmacological and clinical effects not being predictable, while marketed products vary greatly in phytocompounds warrant further empirical investigation. Given the healthcare challenges to manage acute and chronic pain, this review highlights both cannabis and CBD‐hemp extracts to help identify the therapeutic application for patient populations suffering from anxiety, inflammation, and dental pain.
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Affiliation(s)
- Ammaar H Abidi
- College of Dentistry, Department of Bioscience Research, The University of Tennessee Health Science Center, Memphis, Tennessee, USA.,College of Dentistry, Department of General Dentistry, The University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Sahar S Alghamdi
- Department of Phamaceutical Sciences, College of Pharmacy, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia.,King Abdullah International Medical Research Center (KAIMRC), Ministry of National Guard Health Affairs, Riyadh, Kingdom of Saudi Arabia
| | - Karen Derefinko
- College of Medicine, Department of Pharmacology, Addiction Science, and Toxicology, The University of Tennessee Health Science Center, Memphis, Tennessee, USA.,College of Medicine, Department of Preventive Medicine, The University of Tennessee Health Science Center, Memphis, Tennessee, USA
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7
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Murkar A, De Koninck J, Merali Z. Cannabinoids: Revealing their complexity and role in central networks of fear and anxiety. Neurosci Biobehav Rev 2021; 131:30-46. [PMID: 34487746 DOI: 10.1016/j.neubiorev.2021.09.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 08/29/2021] [Accepted: 09/01/2021] [Indexed: 12/11/2022]
Abstract
The first aim of the present review is to provide an in-depth description of the cannabinoids and their known effects at various neuronal receptors. It reveals that cannabinoids are highly diverse, and recent work has highlighted that their effects on the central nervous system (CNS) are surprisingly more complex than previously recognized. Cannabinoid-sensitive receptors are widely distributed throughout the CNS where they act as primary modulators of neurotransmission. Secondly, we examine the role of cannabinoid receptors at key brain sites in the control of fear and anxiety. While our understanding of how cannabinoids specifically modulate these networks is mired by their complex interactions and diversity, a plausible framework(s) for their effects is proposed. Finally, we highlight some important knowledge gaps in our understanding of the mechanism(s) responsible for their effects on fear and anxiety in animal models and their use as therapeutic targets in humans. This is particularly important for our understanding of the phytocannabinoids used as novel clinical interventions.
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Affiliation(s)
- Anthony Murkar
- University of Ottawa Institute of Mental Health Research (IMHR), Ottawa, ON, Canada; School of Psychology, University of Ottawa, Ottawa, ON, Canada.
| | - Joseph De Koninck
- University of Ottawa Institute of Mental Health Research (IMHR), Ottawa, ON, Canada; School of Psychology, University of Ottawa, Ottawa, ON, Canada
| | - Zul Merali
- School of Psychology, University of Ottawa, Ottawa, ON, Canada; Brain and Mind Institute, Aga Khan University, Nairobi, Kenya; Carleton University, Neuroscience Department, Ottawa, ON, Canada
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8
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Gomes-de-Souza L, Bianchi PC, Costa-Ferreira W, Tomeo RA, Cruz FC, Crestani CC. CB 1 and CB 2 receptors in the bed nucleus of the stria terminalis differently modulate anxiety-like behaviors in rats. Prog Neuropsychopharmacol Biol Psychiatry 2021; 110:110284. [PMID: 33609604 DOI: 10.1016/j.pnpbp.2021.110284] [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: 10/27/2020] [Revised: 02/09/2021] [Accepted: 02/10/2021] [Indexed: 01/01/2023]
Abstract
The endocannabinoid system is implicated in anxiety, but the brain sites involved are not completely understood. The bed nucleus of the stria terminalis (BNST) has been related to anxiety and responses to aversive threats. Besides, endocannabinoid neurotransmission acting via CB1 receptors was identified in the BNST. However, the presence of CB2 receptors and the role of BNST endocannabinoid system in anxiety-like behaviors have never been reported. Therefore, this study investigated the presence of CB1 and CB2 receptors in the BNST and their role in anxiety-like behaviors. For this, gene expression of the endocannabinoid receptors was evaluated in samples from anterior and posterior BNST. Besides, behaviors were evaluated in the elevated plus-maze (EPM) in unstressed rats (trait anxiety-like behavior) and after exposure to restraint stress (restraint-evoked anxiety-like behavior) in rats treated with either the CB1 receptor antagonist AM251 or the CB2 receptor antagonist JTE907 into the anterior BNST. The presence of CB1 and CB2 receptors gene expression was identified in anterior and posterior divisions of the BNST. Bilateral microinjection of AM251 into the anterior BNST dose-dependently increased EPM open arms exploration in unstressed animals and inhibited the anxiety-like behavior in the EPM evoked by restraint. Conversely, intra-BNST microinjection of JTE907 decreased EPM open arms exploration in a dose-dependent manner and inhibited restraint-evoked behavioral changes in the EPM. Taken together, these results indicate that CB1 and CB2 receptors present in the BNST are involved in control of anxiety-like behaviors, and control by the latter is affected by previous stress experience.
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Affiliation(s)
- Lucas Gomes-de-Souza
- Laboratory of Pharmacology, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara, SP, Brazil; Joint UFSCar-UNESP Graduate Program in Physiological Sciences, São Carlos, SP, Brazil
| | - Paula C Bianchi
- Department of Pharmacology, Paulista Medicine School, São Paulo Federal University, São Paulo, Brazil
| | - Willian Costa-Ferreira
- Laboratory of Pharmacology, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara, SP, Brazil; Joint UFSCar-UNESP Graduate Program in Physiological Sciences, São Carlos, SP, Brazil
| | - Rodrigo A Tomeo
- Laboratory of Pharmacology, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara, SP, Brazil; Joint UFSCar-UNESP Graduate Program in Physiological Sciences, São Carlos, SP, Brazil
| | - Fábio C Cruz
- Department of Pharmacology, Paulista Medicine School, São Paulo Federal University, São Paulo, Brazil
| | - Carlos C Crestani
- Laboratory of Pharmacology, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara, SP, Brazil; Joint UFSCar-UNESP Graduate Program in Physiological Sciences, São Carlos, SP, Brazil.
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9
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Estrada JA, Contreras I. Endocannabinoid Receptors in the CNS: Potential Drug Targets for the Prevention and Treatment of Neurologic and Psychiatric Disorders. Curr Neuropharmacol 2021; 18:769-787. [PMID: 32065105 PMCID: PMC7536826 DOI: 10.2174/1570159x18666200217140255] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 12/14/2019] [Accepted: 02/11/2020] [Indexed: 12/15/2022] Open
Abstract
The endocannabinoid system participates in the regulation of CNS homeostasis and functions, including neurotransmission, cell signaling, inflammation and oxidative stress, as well as neuronal and glial cell proliferation, differentiation, migration and survival. Endocannabinoids are produced by multiple cell types within the CNS and their main receptors, CB1 and CB2, are expressed in both neurons and glia. Signaling through these receptors is implicated in the modulation of neuronal and glial alterations in neuroinflammatory, neurodegenerative and psychiatric conditions, including Alzheimer’s, Parkinson’s and Huntington’s disease, multiple sclerosis, amyotrophic lateral sclerosis, stroke, epilepsy, anxiety and depression. The therapeutic potential of endocannabinoid receptors in neurological disease has been hindered by unwelcome side effects of current drugs used to target them; however, due to their extensive expression within the CNS and their involvement in physiological and pathological process in nervous tissue, they are attractive targets for drug development. The present review highlights the potential applications of the endocannabinoid system for the prevention and treatment of neurologic and psychiatric disorders.
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Affiliation(s)
- José Antonio Estrada
- Neurochemistry Laboratory, Faculty of Medicine, Universidad Autónoma del Estado de México, Toluca, Mexico
| | - Irazú Contreras
- Neurochemistry Laboratory, Faculty of Medicine, Universidad Autónoma del Estado de México, Toluca, Mexico
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Morris G, Walder K, Kloiber S, Amminger P, Berk M, Bortolasci CC, Maes M, Puri BK, Carvalho AF. The endocannabinoidome in neuropsychiatry: Opportunities and potential risks. Pharmacol Res 2021; 170:105729. [PMID: 34119623 DOI: 10.1016/j.phrs.2021.105729] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 05/31/2021] [Accepted: 06/09/2021] [Indexed: 02/08/2023]
Abstract
The endocannabinoid system (ECS) comprises two cognate endocannabinoid receptors referred to as CB1R and CB2R. ECS dysregulation is apparent in neurodegenerative/neuro-psychiatric disorders including but not limited to schizophrenia, major depressive disorder and potentially bipolar disorder. The aim of this paper is to review mechanisms whereby both receptors may interact with neuro-immune and neuro-oxidative pathways, which play a pathophysiological role in these disorders. CB1R is located in the presynaptic terminals of GABAergic, glutamatergic, cholinergic, noradrenergic and serotonergic neurons where it regulates the retrograde suppression of neurotransmission. CB1R plays a key role in long-term depression, and, to a lesser extent, long-term potentiation, thereby modulating synaptic transmission and mediating learning and memory. Optimal CB1R activity plays an essential neuroprotective role by providing a defense against the development of glutamate-mediated excitotoxicity, which is achieved, at least in part, by impeding AMPA-mediated increase in intracellular calcium overload and oxidative stress. Moreover, CB1R activity enables optimal neuron-glial communication and the function of the neurovascular unit. CB2R receptors are detected in peripheral immune cells and also in central nervous system regions including the striatum, basal ganglia, frontal cortex, hippocampus, amygdala as well as the ventral tegmental area. CB2R upregulation inhibits the presynaptic release of glutamate in several brain regions. CB2R activation also decreases neuroinflammation partly by mediating the transition from a predominantly neurotoxic "M1" microglial phenotype to a more neuroprotective "M2" phenotype. CB1R and CB2R are thus novel drug targets for the treatment of neuro-immune and neuro-oxidative disorders including schizophrenia and affective disorders.
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Affiliation(s)
- Gerwyn Morris
- Deakin University, IMPACT - the Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Barwon Health, Geelong, Australia
| | - Ken Walder
- Deakin University, IMPACT - the Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Barwon Health, Geelong, Australia; Deakin University, Centre for Molecular and Medical Research, School of Medicine, Geelong, Australia
| | - Stefan Kloiber
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 33 Ursula Franklin Street, Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Paul Amminger
- Orygen, Parkville, Victoria, Australia; Centre for Youth Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Michael Berk
- Deakin University, IMPACT - the Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Barwon Health, Geelong, Australia; Orygen, The National Centre of Excellence in Youth Mental Health, Centre for Youth Mental Health, Florey Institute for Neuroscience and Mental Health and the Department of Psychiatry, The University of Melbourne, Melbourne, Australia
| | - Chiara C Bortolasci
- Deakin University, IMPACT - the Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Barwon Health, Geelong, Australia
| | - Michael Maes
- Deakin University, IMPACT - the Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Barwon Health, Geelong, Australia; Department of Psychiatry, Faculty of Medicine, King Chulalongkorn Memorial Hospital, Bangkok, Thailand; Department of Psychiatry, Medical University of Plovdiv, Plovdiv, Bulgaria
| | | | - Andre F Carvalho
- Deakin University, IMPACT - the Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Barwon Health, Geelong, Australia.
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Sharma DS, Paddibhatla I, Raghuwanshi S, Malleswarapu M, Sangeeth A, Kovuru N, Dahariya S, Gautam DK, Pallepati A, Gutti RK. Endocannabinoid system: Role in blood cell development, neuroimmune interactions and associated disorders. J Neuroimmunol 2021; 353:577501. [PMID: 33571815 DOI: 10.1016/j.jneuroim.2021.577501] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 01/03/2021] [Accepted: 01/24/2021] [Indexed: 12/19/2022]
Abstract
The endocannabinoid system (ECS) is a complex physiological network involved in creating homeostasis and maintaining human health. Studies of the last 40 years have shown that endocannabinoids (ECs), a group of bioactive lipids, together with their set of receptors, function as one of the most important physiologic systems in human body. ECs and cannabinoid receptors (CBRs) are found throughout the body: in the brain tissues, immune cells, and in the peripheral organs and tissues as well. In recent years, ECs have emerged as key modulators of affect, neurotransmitter release, immune function, and several other physiological functions. This modulatory homoeostatic system operates in the regulation of brain activity and states of physical health and disease. In several research studies and patents the ECS has been recognised with neuro-protective properties thus it might be a target in neurodegenerative diseases. Most immune cells express these bioactive lipids and their receptors, recent data also highlight the immunomodulatory effects of endocannabinoids. Interplay of immune and nervous system has been recognized in past, recent studies suggest that ECS function as a bridge between neuronal and immune system. In several ongoing clinical trial studies, the ECS has also been placed in the anti-cancer drugs spotlight. This review summarizes the literature of cannabinoid ligands and their biosynthesis, cannabinoid receptors and their distribution, and the signaling pathways initiated by the binding of cannabinoid ligands to cannabinoid receptors. Further, this review highlights the functional role of cannabinoids and ECS in blood cell development, neuroimmune interactions and associated disorders. Moreover, we highlight the current state of knowledge of cannabinoid ligands as the mediators of neuroimmune interactions, which can be therapeutically effective for neuro-immune disorders and several diseases associated with neuroinflammation.
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Affiliation(s)
- Durga Shankar Sharma
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad 500046, Telangana, India
| | - Indira Paddibhatla
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad 500046, Telangana, India
| | - Sanjeev Raghuwanshi
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad 500046, Telangana, India
| | - Mahesh Malleswarapu
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad 500046, Telangana, India
| | - Anjali Sangeeth
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad 500046, Telangana, India
| | - Narasaiah Kovuru
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad 500046, Telangana, India
| | - Swati Dahariya
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad 500046, Telangana, India
| | - Dushyant Kumar Gautam
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad 500046, Telangana, India
| | - Aditya Pallepati
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad 500046, Telangana, India
| | - Ravi Kumar Gutti
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad 500046, Telangana, India.
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Cannabinoid type 2 receptors inhibit GABAA receptor-mediated currents in cerebellar Purkinje cells of juvenile mice. PLoS One 2020; 15:e0233020. [PMID: 32437355 PMCID: PMC7241750 DOI: 10.1371/journal.pone.0233020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 04/28/2020] [Indexed: 12/15/2022] Open
Abstract
Signaling through the endocannabinoid system is critical to proper functioning of the cerebellar circuit. However, most studies have focused on signaling through cannabinoid type 1 (CB1) receptors, while relatively little is known about signaling through type 2 (CB2) receptors. We show that functional CB2 receptors are expressed in Purkinje cells using a combination of immunohistochemistry and patch-clamp electrophysiology in juvenile mice. Pharmacological activation of CB2 receptors significantly reduces inhibitory synaptic responses and currents mediated by photolytic uncaging of RuBi-GABA in Purkinje cells. CB2 receptor activation does not change the paired-pulse ratio of inhibitory responses and its effects are blocked by inclusion of GDP-β-S in the internal solution, indicating a postsynaptic mechanism of action. However, CB2 receptors do not contribute to depolarization induced suppression of inhibition (DSI), indicating they are not activated by endocannabinoids synthesized and released from Purkinje cells using this protocol. This work demonstrates that CB2 receptors inhibit postsynaptic GABAA receptors by a postsynaptic mechanism in Purkinje cells. This represents a novel mechanism by which CB2 receptors may modulate neuronal and circuit function in the central nervous system.
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ZUBRZYCKI M, STASIOLEK M, ZUBRZYCKA M. Opioid and Endocannabinoid System in Orofacial Pain. Physiol Res 2019; 68:705-715. [DOI: 10.33549/physiolres.934159] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Orofacial pain disorders are frequent in the general population and their pharmacological treatment is difficult and controversial. Therefore, the search for novel, safe and efficient analgesics is an important but still elusive goal for contemporary medicine. In the recent years, the antinociceptive potential of endocannabinoids and opioids has been emphasized. However, concerns for the safety of their use limit their clinical applications. the possibility of modulating the activity of endocannabinoids by regulation of their synthesis and/or degradation offers an innovative approach to the treatment of pain. A rat model of trigeminal pain, utilizing tongue jerks evoked by electrical tooth pulp stimulation during perfusion of the cerebral ventricles with various neurotransmitter solutions can be used in the pharmacological studies of nociception in the orofacial area. The aim of this review is to present the effects of pharmacological activity of opioids and endocannabinoids affecting the transmission of the sensory information from the orofacial area on the example of trigemino-hypoglossal reflex in rats.
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Affiliation(s)
- M. ZUBRZYCKI
- Department of Cardiovascular and Thoracic Surgery, University of Ulm, Ulm, Germany,
| | - M. STASIOLEK
- Department of Neurology, Medical University of Lodz, Lodz, Poland
| | - M. ZUBRZYCKA
- Department of Cardiovascular Physiology, Interdepartmental Chair of Experimental and Clinical Physiology, Medical University of Lodz, Lodz, Poland
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14
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Ma Z, Gao F, Larsen B, Gao M, Luo Z, Chen D, Ma X, Qiu S, Zhou Y, Xie J, Xi ZX, Wu J. Mechanisms of cannabinoid CB 2 receptor-mediated reduction of dopamine neuronal excitability in mouse ventral tegmental area. EBioMedicine 2019; 42:225-237. [PMID: 30952618 PMCID: PMC6491419 DOI: 10.1016/j.ebiom.2019.03.040] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 02/24/2019] [Accepted: 03/14/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND We have recently reported that activation of cannabinoid type 2 receptors (CB2Rs) reduces dopamine (DA) neuron excitability in mouse ventral tegmental area (VTA). Here, we elucidate the underlying mechanisms. METHODS Patch-clamp recordings were performed in mouse VTA slices and dissociated single VTA DA neurons. FINDINGS Using cell-attached recording in VTA slices, bath-application of CB2R agonists (JWH133 or five other CB2R agonists) significantly reduced VTA DA neuron action potential (AP) firing rate. Under the patch-clamp whole-cell recording model, JWH133 (10 μM) mildly reduced the frequency of miniature excitatory postsynaptic currents (mEPSCs) but not miniature inhibitory postsynaptic currents (mIPSCs). JWH133 also did not alter evoked EPSCs or IPSCs. In freshly dissociated VTA DA neurons, JWH133 reduced AP firing rate, delayed AP initiation and enhanced AP after-hyperpolarization. In voltage-clamp recordings, JWH133 (1 μM) enhanced M-type K+ currents and this effect was absent in CB2-/- mice and abolished by co-administration of a selective CB2R antagonist (10 μM, AM630). CB2R-mediated inhibition in VTA DA neuron firing can be mimicked by M-current opener (10 μM retigabine) and blocked by M-current blocker (30 μM XE991). In addition, enhancement of neuronal cAMP by forskolin (10 μM) reduced M-current and increased DA neuron firing rate. Finally, pharmacological block of synaptic transmission by NBQX (10 μM), D-APV (50 μM) and picrotoxin (100 μM) in VTA slices failed to prevent CB2R-mediated inhibition, while intracellular infusion of guanosine 5'-O-2-thiodiphosphate (600 μM, GDP-β-S) through recording electrode to block postsynaptic G-protein function prevented JWH133-induced reduction in AP firing. INTERPRETATION Our results suggest that CB2Rs modulate VTA DA neuron excitability mainly through an intrinsic mechanism, including a CB2R-mediated reduction of intracellular cAMP, and in turn enhancement of M-type K+ currents. FUND: This research was supported by the Barrow Neuroscience Foundation, the BNI-BMS Seed Fund, and CNSF (81771437).
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Affiliation(s)
- Zegang Ma
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao 266071, China; Department of Neurobiology, St. Joseph's Hospital and Medical Center, Barrow Neurological Institute, Phoenix, AZ 85013, USA
| | - Fenfei Gao
- Department of Pharmacology, Shantou University Medical College, Shantou, Guangdong 210854, China; Department of Neurobiology, St. Joseph's Hospital and Medical Center, Barrow Neurological Institute, Phoenix, AZ 85013, USA
| | - Brett Larsen
- Department of Neurobiology, St. Joseph's Hospital and Medical Center, Barrow Neurological Institute, Phoenix, AZ 85013, USA; Department of Basic Medical Sciences, University of Arizona College of Medicine, Phoenix, AZ 85004, USA
| | - Ming Gao
- Department of Neurobiology, St. Joseph's Hospital and Medical Center, Barrow Neurological Institute, Phoenix, AZ 85013, USA
| | - Zhihua Luo
- Department of Pharmacology, Shantou University Medical College, Shantou, Guangdong 210854, China
| | - Dejie Chen
- Department of Neurobiology, St. Joseph's Hospital and Medical Center, Barrow Neurological Institute, Phoenix, AZ 85013, USA; Department of Neurology, Yunfu People's Hospital, Yunfu, Guangdong 527300, China
| | - Xiaokuang Ma
- Department of Neurobiology, St. Joseph's Hospital and Medical Center, Barrow Neurological Institute, Phoenix, AZ 85013, USA; Department of Pharmacology, Shantou University Medical College, Shantou, Guangdong 210854, China; Department of Basic Medical Sciences, University of Arizona College of Medicine, Phoenix, AZ 85004, USA
| | - Shenfeng Qiu
- Department of Basic Medical Sciences, University of Arizona College of Medicine, Phoenix, AZ 85004, USA
| | - Yu Zhou
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao 266071, China
| | - Junxia Xie
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao 266071, China
| | - Zheng-Xiong Xi
- Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse, Baltimore, MD 21224, USA
| | - Jie Wu
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao 266071, China; Department of Neurobiology, St. Joseph's Hospital and Medical Center, Barrow Neurological Institute, Phoenix, AZ 85013, USA; Department of Pharmacology, Shantou University Medical College, Shantou, Guangdong 210854, China; Department of Neurology, Yunfu People's Hospital, Yunfu, Guangdong 527300, China.
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15
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Ghosh S, Sheth S, Sheehan K, Mukherjea D, Dhukhwa A, Borse V, Rybak LP, Ramkumar V. The Endocannabinoid/Cannabinoid Receptor 2 System Protects Against Cisplatin-Induced Hearing Loss. Front Cell Neurosci 2018; 12:271. [PMID: 30186120 PMCID: PMC6110918 DOI: 10.3389/fncel.2018.00271] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 08/03/2018] [Indexed: 12/22/2022] Open
Abstract
Previous studies have demonstrated the presence of cannabinoid 2 receptor (CB2R) in the rat cochlea which was induced by cisplatin. In an organ of Corti-derived cell culture model, it was also shown that an agonist of the CB2R protected these cells against cisplatin-induced apoptosis. In the current study, we determined the distribution of CB2R in the mouse and rat cochleae and examined whether these receptors provide protection against cisplatin-induced hearing loss. In a knock-in mouse model expressing the CB2R tagged with green fluorescent protein, we show distribution of CB2R in the organ of Corti, stria vascularis, spiral ligament and spiral ganglion cells. A similar distribution of CB2R was observed in the rat cochlea using a polyclonal antibody against CB2R. Trans-tympanic administration of (2-methyl-1-propyl-1H-indol-3-yl)-1-naphthalenylmethanone (JWH015), a selective agonist of the CB2R, protected against cisplatin-induced hearing loss which was reversed by blockade of this receptor with 6-iodo-2-methyl-1-[2-(4-morpholinyl)ethyl]-1H-indol-3-yl](4-methoxyphenyl)methanone (AM630), an antagonist of CB2R. JWH015 also reduced the loss of outer hair cells (OHCs) in the organ of Corti, loss of inner hair cell (IHC) ribbon synapses and loss of Na+/K+-ATPase immunoreactivity in the stria vascularis. Administration of AM630 alone produced significant hearing loss (measured by auditory brainstem responses) which was not associated with loss of OHCs, but led to reductions in the levels of IHC ribbon synapses and strial Na+/K+-ATPase immunoreactivity. Furthermore, knock-down of CB2R by trans-tympanic administration of siRNA sensitized the cochlea to cisplatin-induced hearing loss at the low and middle frequencies. Hearing loss induced by cisplatin and AM630 in the rat was associated with increased expression of genes for oxidative stress and inflammatory proteins in the rat cochlea. In vitro studies indicate that JWH015 did not alter cisplatin-induced killing of cancer cells suggesting this agent could be safely used during cisplatin chemotherapy. These data unmask a protective role of the cochlear endocannabinoid/CB2R system which appears tonically active under normal conditions to preserve normal hearing. However, an exogenous agonist is needed to boost the activity of endocannabinoid/CB2R system for protection against a more traumatic cochlear insult, as observed with cisplatin administration.
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Affiliation(s)
- Sumana Ghosh
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Sandeep Sheth
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Kelly Sheehan
- Department of Surgery, Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Debashree Mukherjea
- Department of Surgery, Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Asmita Dhukhwa
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Vikrant Borse
- Department of Otolaryngology, School of Medicine, Washington University in St. Louis, St. Louis, MO, United States
| | - Leonard P Rybak
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, United States.,Department of Surgery, Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Vickram Ramkumar
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, United States
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Sánchez-Zavaleta R, Cortés H, Avalos-Fuentes JA, García U, Segovia Vila J, Erlij D, Florán B. Presynaptic cannabinoid CB2 receptors modulate [ 3 H]-Glutamate release at subthalamo-nigral terminals of the rat. Synapse 2018; 72:e22061. [PMID: 30022523 DOI: 10.1002/syn.22061] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 07/12/2018] [Accepted: 07/13/2018] [Indexed: 11/08/2022]
Abstract
Recent studies suggested the expression of CB2 receptors in neurons of the CNS, however, most of these studies have only explored one aspect of the receptors, i.e., expression of protein, messenger RNA, or functional response, and more complete studies appear to be needed to establish adequately their role in the neuronal function. Electron microscopy studies showed the presence of CB2r in asymmetric terminals of the substantia nigra pars reticulata (SNr), and its mRNA appeared is expressed in the subthalamic nucleus. Here, we explore the expression, source, and functional effects of such receptors by different experimental approaches. Through PCR and immunochemistry, we showed mRNA and protein for CB2rs in slices and primary neuronal cultures from subthalamus. GW833972A, GW405833, and JHW 133, three CB2r agonists dose-dependent inhibited K+ -induced [3 H]-Glutamate release in slices of SNr, and the two antagonist/inverse agonists, JTE-907 and AM630, but not AM281, a CB1r antagonist, prevented GW833972A effect. Subthalamus lesions with kainic acid prevented GW833972A inhibition on release and decreased CB2r protein in nigral synaptosomes, thus nigral CB2rs originate in subthalamus. Inhibition of [3 H]-Glutamate release was PTX- and gallein-sensitive, suggesting a Giβγ -mediated effect. P/Q Ca2+ -type channel blocker, ω-Agatoxin-TK, also inhibited the [3 H]-Glutamate release, this effect was occluded with GW833972A inhibition, indicating that the βγ subunit effect is exerted on Ca2+ channel activity. Finally, microinjections of GW833972A in SNr induced contralateral turning. Our data showed that presynaptic CB2rs inhibit [3 H]-Glutamate release in subthalamo-nigral terminals by P/Q-channels modulation through the Giβγ subunit and suggested their participation in motor behavior.
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Affiliation(s)
- Rodolfo Sánchez-Zavaleta
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México City, México
| | - Hernán Cortés
- Laboratorio de Medicina Genómica, Departamento de Genética, Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra, Ciudad de México, México
| | - José Arturo Avalos-Fuentes
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México City, México
| | - Ubaldo García
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México City, México
| | - José Segovia Vila
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México City, México
| | - David Erlij
- Department of Physiology, SUNY Downstate Medical Center, Brooklyn, New York
| | - Benjamín Florán
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México City, México
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17
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Mardani P, Oryan S, Sarihi A, Alaei E, Komaki A, Mirnajafi-Zadeh J. Endocannabinoid CB1 receptors are involved in antiepileptogenic effect of low frequency electrical stimulation during perforant path kindling in rats. Epilepsy Res 2018; 144:71-81. [PMID: 29800824 DOI: 10.1016/j.eplepsyres.2018.05.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 04/27/2018] [Accepted: 05/14/2018] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Administration of low-frequency electrical stimulation (LFS) at the kindling site has an antiepileptogenic effect. In the present study, we investigated the role of cannabinoid receptors type 1 (CB1) in mediating the inhibitory effects of LFS on the development of perforant path kindled seizures. METHODS For seizure generation, rats were kindled by electrical stimulation of perforant path in semi-rapid kindling manner (12 stimulations per day at 10 min intervals at afterdischarge threshold intensity).To determine the effect of LFS (0.1 ms pulse duration at 1 Hz, 800 pulses) on seizure generation, LFS was applied to the perforant path 5 min after the last kindling stimulation daily. AM281, a CB1 receptor antagonist, was microinjected into the lateral ventricle immediately after the last kindling stimulation (before LFS application) at the doses of 0.5 and 2 μg/μl during kindling procedure. The expression of cannabinoid receptors in the dentate gyrus was also investigated using immunohistochemistry. RESULTS Application of LFS had inhibitory effect on development of kindled seizures (kindling rate). Microinjection of AM281 (0.5 μg/μl) immediately after the last kindling stimulation (before LFS application) reduced the inhibitory effect of LFS on the kindling rate and suppressed the effects of LFS on potentiation (increasing the magnitude) of both population spike amplitude and population excitatory postsynaptic potential slope during kindling acquisition. AM281 pretreatment also prevented the effects of LFS on kindling-induced increase in early and late paired pulse depression. The higher dose of AM281 (2 μg/μl) failed to exert the effects observed with its lower dose (0.5 μg/μl). In addition, there was a decreased CB1 receptors immunostaining in kindled animals compared to control. However, application of LFS following kindling stimulations led to overexpression of CB1 receptors in the dentate gyrus. CONCLUSION Obtained results showed that activation of overexpressed cannabinoid CB1 receptors by endogenous cannabinoids may have a role in mediating the inhibitory effect of LFS on perforant path kindled seizures.
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Affiliation(s)
- Parastoo Mardani
- Department of Animal Biology, Faculty of Biological Science, Kharazmi University, Tehran, Iran; Department of Biology, Faculty of Sciences, Payame Noor University, Iran.
| | - Shahrbanoo Oryan
- Department of Animal Biology, Faculty of Biological Science, Kharazmi University, Tehran, Iran
| | - Abdolrahman Sarihi
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Elham Alaei
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Alireza Komaki
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Javad Mirnajafi-Zadeh
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
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18
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Baggelaar MP, Maccarrone M, van der Stelt M. 2-Arachidonoylglycerol: A signaling lipid with manifold actions in the brain. Prog Lipid Res 2018; 71:1-17. [PMID: 29751000 DOI: 10.1016/j.plipres.2018.05.002] [Citation(s) in RCA: 124] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 05/03/2018] [Accepted: 05/06/2018] [Indexed: 11/19/2022]
Abstract
2-Arachidonoylglycerol (2-AG) is a signaling lipid in the central nervous system that is a key regulator of neurotransmitter release. 2-AG is an endocannabinoid that activates the cannabinoid CB1 receptor. It is involved in a wide array of (patho)physiological functions, such as emotion, cognition, energy balance, pain sensation and neuroinflammation. In this review, we describe the biosynthetic and metabolic pathways of 2-AG and how chemical and genetic perturbation of these pathways has led to insight in the biological role of this signaling lipid. Finally, we discuss the potential therapeutic benefits of modulating 2-AG levels in the brain.
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Affiliation(s)
- Marc P Baggelaar
- Department of Molecular Physiology, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Mauro Maccarrone
- Department of Medicine, Campus Bio-Medico University of Rome, Via Alvaro del Portillo 21, 00128 Rome, Italy; European Centre for Brain Research/IRCCS Santa Lucia Foundation, via del Fosso del Fiorano 65, 00143 Rome, Italy
| | - Mario van der Stelt
- Department of Molecular Physiology, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands..
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19
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Liu QR, Canseco-Alba A, Zhang HY, Tagliaferro P, Chung M, Dennis E, Sanabria B, Schanz N, Escosteguy-Neto JC, Ishiguro H, Lin Z, Sgro S, Leonard CM, Santos-Junior JG, Gardner EL, Egan JM, Lee JW, Xi ZX, Onaivi ES. Cannabinoid type 2 receptors in dopamine neurons inhibits psychomotor behaviors, alters anxiety, depression and alcohol preference. Sci Rep 2017; 7:17410. [PMID: 29234141 PMCID: PMC5727179 DOI: 10.1038/s41598-017-17796-y] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 11/30/2017] [Indexed: 12/31/2022] Open
Abstract
Cannabinoid CB2 receptors (CB2Rs) are expressed in mouse brain dopamine (DA) neurons and are involved in several DA-related disorders. However, the cell type-specific mechanisms are unclear since the CB2R gene knockout mice are constitutive gene knockout. Therefore, we generated Cnr2-floxed mice that were crossed with DAT-Cre mice, in which Cre- recombinase expression is under dopamine transporter gene (DAT) promoter control to ablate Cnr2 gene in midbrain DA neurons of DAT-Cnr2 conditional knockout (cKO) mice. Using a novel sensitive RNAscope in situ hybridization, we detected CB2R mRNA expression in VTA DA neurons in wildtype and DAT-Cnr2 cKO heterozygous but not in the homozygous DAT-Cnr2 cKO mice. Here we report that the deletion of CB2Rs in dopamine neurons enhances motor activities, modulates anxiety and depression-like behaviors and reduces the rewarding properties of alcohol. Our data reveals that CB2Rs are involved in the tetrad assay induced by cannabinoids which had been associated with CB1R agonism. GWAS studies indicates that the CNR2 gene is associated with Parkinson's disease and substance use disorders. These results suggest that CB2Rs in dopaminergic neurons may play important roles in the modulation of psychomotor behaviors, anxiety, depression, and pain sensation and in the rewarding effects of alcohol and cocaine.
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Affiliation(s)
- Qing-Rong Liu
- Department of Biology, William Paterson University, Wayne, New Jersey, 74070, USA.
- Laboratory of Clinical Investigation, national Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA.
| | - Ana Canseco-Alba
- Department of Biology, William Paterson University, Wayne, New Jersey, 74070, USA
| | - Hai-Ying Zhang
- Molecular Targets and medications Discovery Branch, Intramural Research Program. National Institute on Drug Abuse, Baltimore, MD, 21224, USA
| | - Patricia Tagliaferro
- Department of Biology, William Paterson University, Wayne, New Jersey, 74070, USA
| | - Monika Chung
- Department of Biology, William Paterson University, Wayne, New Jersey, 74070, USA
| | - Eugene Dennis
- Department of Biology, William Paterson University, Wayne, New Jersey, 74070, USA
| | - Branden Sanabria
- Department of Biology, William Paterson University, Wayne, New Jersey, 74070, USA
| | - Norman Schanz
- Department of Biology, William Paterson University, Wayne, New Jersey, 74070, USA
| | | | - Hiroki Ishiguro
- Department of Psychiatry, University of Yamanashi, Yamanashi, Japan
| | - 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
| | - Susan Sgro
- Department of Biology, William Paterson University, Wayne, New Jersey, 74070, USA
| | - Claire M Leonard
- Department of Biology, William Paterson University, Wayne, New Jersey, 74070, USA
| | | | - Eliot L Gardner
- Molecular Targets and medications Discovery Branch, Intramural Research Program. National Institute on Drug Abuse, Baltimore, MD, 21224, USA
| | - Josephine M Egan
- Laboratory of Clinical Investigation, national Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Jeung Woon Lee
- Department of Biology, William Paterson University, Wayne, New Jersey, 74070, USA
| | - Zheng-Xiong Xi
- Molecular Targets and medications Discovery Branch, Intramural Research Program. National Institute on Drug Abuse, Baltimore, MD, 21224, USA
| | - Emmanuel S Onaivi
- Department of Biology, William Paterson University, Wayne, New Jersey, 74070, USA.
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20
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Compensatory Activation of Cannabinoid CB2 Receptor Inhibition of GABA Release in the Rostral Ventromedial Medulla in Inflammatory Pain. J Neurosci 2017; 37:626-636. [PMID: 28100744 DOI: 10.1523/jneurosci.1310-16.2016] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 11/29/2016] [Accepted: 12/02/2016] [Indexed: 12/12/2022] Open
Abstract
The rostral ventromedial medulla (RVM) is a relay in the descending pain modulatory system and an important site of endocannabinoid modulation of pain. Endocannabinoids inhibit GABA release in the RVM, but it is not known whether this effect persists in chronic pain states. In the present studies, persistent inflammation induced by complete Freund's adjuvant (CFA) increased GABAergic miniature IPSCs (mIPSCs). Endocannabinoid activation of cannabinoid (CB1) receptors known to inhibit presynaptic GABA release was significantly reduced in the RVM of CFA-treated rats compared with naive rats. The reduction in CFA-treated rats correlated with decreased CB1 receptor protein expression and function in the RVM. Paradoxically, the nonselective CB1/CB2 receptor agonist WIN55212 inhibited GABAergic mIPSCs in both naive and CFA-treated rats. However, WIN55212 inhibition was reversed by the CB1 receptor antagonist rimonabant in naive rats but not in CFA-treated rats. WIN55212-mediated inhibition in CFA-treated rats was blocked by the CB2 receptor-selective antagonist SR144528, indicating that CB2 receptor function in the RVM is increased during persistent inflammation. Consistent with these results, CB2 receptor agonists AM1241 and GW405833 inhibited GABAergic mIPSC frequency only in CFA-treated rats, and the inhibition was reversed with SR144528. When administered alone, SR144528 and another CB2 receptor-selective antagonist AM630 increased mIPSC frequency in the RVM of CFA-treated rats, indicating that CB2 receptors are tonically activated by endocannabinoids. Our data provide evidence that CB2 receptor function emerges in the RVM in persistent inflammation and that selective CB2 receptor agonists may be useful for treatment of persistent inflammatory pain. SIGNIFICANCE STATEMENT These studies demonstrate that endocannabinoid signaling to CB1 and CB2 receptors in adult rostral ventromedial medulla is altered in persistent inflammation. The emergence of CB2 receptor function in the rostral ventromedial medulla provides additional rationale for the development of CB2 receptor-selective agonists as useful therapeutics for chronic inflammatory pain.
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Cannabinoid CB1 and CB2 receptors differentially modulate L- and T-type Ca 2+ channels in rat retinal ganglion cells. Neuropharmacology 2017; 124:143-156. [PMID: 28431968 DOI: 10.1016/j.neuropharm.2017.04.027] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 03/15/2017] [Accepted: 04/17/2017] [Indexed: 01/09/2023]
Abstract
Endocannabinoid signaling system is involved in regulating multiple neuronal functions in the central nervous system by activating G-protein coupled cannabinoid CB1 and CB2 receptors (CB1Rs and CB2Rs). Growing evidence has shown that CB1Rs and CB2Rs are extensively expressed in retinal ganglion cells (RGCs). Here, modulation of L- and T-types Ca2+ channels by activating CB1Rs and CB2Rs in RGCs was investigated. Triple immunofluorescent staining showed that L-type subunit CaV1.2 was co-localized with T-type subunits (CaV3.1, CaV3.2 and CaV3.3) in rat RGCs. In acutely isolated rat RGCs, the CB1R agonist WIN55212-2 suppressed both peak and steady-state Ca2+ currents in a dose-dependent manner, with IC50 being 9.6 μM and 8.4 μM, respectively. It was further shown that activation of CB1Rs by WIN55212-2 or ACEA, another CB1R agonist, significantly suppressed both L- and T-type Ca2+ currents, and shifted inactivation curve of T-type one toward hyperpolarization direction. While the effect on L-type Ca2+ channels was mediated by intracellular cAMP/protein kinase A (PKA), mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) and calcium/calmodulin-dependent protein kinase II (CaMKII) signaling pathways, only CaMKII signaling pathway was involved in the effect on T-type Ca2+ channels. Furthermore, CB65 and HU308, two specific CB2R agonists, significantly suppressed T-type Ca2+ channels, which was mediated by intracellular cAMP/PKA and CaMKII signaling pathways, but had no effect on L-type channels. These results imply that endogenous cannabinoids may modulate the excitability and the output of RGCs by differentially suppressing the activity of L- and T-type Ca2+ channels through activation of CB1Rs and CB2Rs. This article is part of the Special Issue entitled "A New Dawn in Cannabinoid Neurobiology".
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Pergolizzi JV, Taylor R, LeQuang JA, Zampogna G, Raffa RB. Concise review of the management of iatrogenic emesis using cannabinoids: emphasis on nabilone for chemotherapy-induced nausea and vomiting. Cancer Chemother Pharmacol 2017; 79:467-477. [PMID: 28235999 DOI: 10.1007/s00280-017-3257-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 02/06/2017] [Indexed: 12/11/2022]
Abstract
Chemotherapy-induced nausea and vomiting (CINV) is a prevalent, distressing, and burdensome side effect of cancer chemotherapy. It is estimated to affect the majority of patients receiving certain anti-cancer drug regimens and can be treatment-limiting, even for life-saving medications. Despite seemingly numerous options, such as antimuscarinic anticholinergics, antihistamines, 5-HT3 receptor antagonists, dopamine receptor antagonists, and neurokinin-1 receptor antagonists, preventative therapies are often inadequately effective, particularly for "delayed CINV"-leaving an important unmet clinical need. Cannabinoid receptor agonists, by virtue of their unique mechanism of action and efficacy and safety data reported in clinical trials, appear to offer a useful additional option. The mechanistic value of cannabinoids has been well known for many years, but these agents may have been underutilized in the past because of the notoriety and legal status of marijuana. While botanical marijuana contains nearly 500 components, including the psychoactive tetrahydrocannabinol (THC), nabilone is an established, single-entity synthetic cannabinoid receptor agonist that has become the focus of renewed interest. We review the basic pharmacology and clinical trial data of nabilone for use in prophylaxis and treatment of CINV.
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Affiliation(s)
| | - Robert Taylor
- NEMA Research, Inc., 868 106th Ave North, Naples, FL, 34108, USA
| | - Jo Ann LeQuang
- NEMA Research, Inc., 868 106th Ave North, Naples, FL, 34108, USA.
| | | | - Robert B Raffa
- University of Arizona College of Pharmacy, Tucson, AZ, USA
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Role of orexin-2 and CB1 receptors within the periaqueductal gray matter in lateral hypothalamic-induced antinociception in rats. Behav Pharmacol 2017; 28:83-89. [DOI: 10.1097/fbp.0000000000000277] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Dhopeshwarkar A, Mackie K. Functional Selectivity of CB2 Cannabinoid Receptor Ligands at a Canonical and Noncanonical Pathway. J Pharmacol Exp Ther 2016; 358:342-51. [PMID: 27194477 PMCID: PMC4959096 DOI: 10.1124/jpet.116.232561] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Accepted: 05/17/2016] [Indexed: 01/14/2023] Open
Abstract
The CB2 cannabinoid receptor (CB2) remains a tantalizing, but unrealized therapeutic target. CB2 receptor ligands belong to varied structural classes and display extreme functional selectivity. Here, we have screened diverse CB2 receptor ligands at canonical (inhibition of adenylyl cyclase) and noncanonical (arrestin recruitment) pathways. The nonclassic cannabinoid (-)-cis-3-[2-hydroxy-4-(1,1-dimethylheptyl)phenyl]-trans-4-(3-hydroxypropyl)cyclohexanol (CP55940) was the most potent agonist for both pathways, while the classic cannabinoid ligand (6aR,10aR)-3-(1,1-Dimethylbutyl)-6a,7,10,10a-tetrahydro-6,6,9-trimethyl-6H-dibenzo[b,d]pyran JWH133) was the most efficacious agonist among all the ligands profiled in cyclase assays. In the cyclase assay, other classic cannabinoids showed little [(-)-trans-Δ(9)-tetrahydrocannabinol and (-)-(6aR,7,10,10aR)-tetrahydro-6,6,9-trimethyl-3-(1-methyl-1-phenylethyl)-6H-dibenzo[b,d]pyran-1-ol] (KM233) to no efficacy [(6aR,10aR)-1-methoxy-6,6,9-trimethyl-3-(2-methyloctan-2-yl)-6a,7,10,10a-tetrahydrobenzo[c]chromene(L759633) and (6aR,10aR)-3-(1,1-dimethylheptyl)-6a,7,8,9,10,10a-hexahydro-1-methoxy-6,6-dimethyl-9-methylene-6H-dibenzo[b,d]pyran]L759656. Most aminoalkylindoles, including [(3R)-2,3-dihydro-5-methyl-3-(4-morpholinylmethyl)pyrrolo[1,2,3-de]-1,4-benzoxazin-6-yl]-1-naphthalenyl-methanone, monomethanesulfonate (WIN55212-2), were moderate efficacy agonists. The cannabilactone 3-(1,1-dimethyl-heptyl)-1-hydroxy-9-methoxy-benzo(c)chromen-6-one (AM1710) was equiefficacious to CP55940 to inhibit adenylyl cyclase, albeit with lower potency. In the arrestin recruitment assays, all classic cannabinoid ligands failed to recruit arrestins, indicating a bias toward G-protein coupling for this class of compound. All aminoalkylindoles tested, except for WIN55212-2 and (1-pentyl-1H-indol-3-yl)(2,2,3,3-tetramethylcyclopropyl)-methanone (UR144), failed to recruit arrestin. WIN55212-2 was a low efficacy agonist for arrestin recruitment, while UR144 was arrestin biased with no significant inhibition of cyclase. Endocannabinoids were G-protein biased with no arrestin recruitment. The diarylpyrazole antagonist 5-(4-chloro-3-methylphenyl)-1-[(4-methylphenyl)methyl]-N-[(1S,2S,4R)-1,3,3-trimethylbicyclo[2.2.1]hept-2-yl]-1H-pyrazole-3-carboxamide (SR144258) was an inverse agonist in cyclase and arrestin recruitment assays while the aminoalkylindole 6-iodo-2-methyl-1-[2-(4-morpholinyl)ethyl]-1H-indol-3-yl](4-methoxyphenyl)methanone (AM630) and carboxamide N-(1,3-benzodioxol-5-ylmethyl)-1,2-dihydro-7-methoxy-2-oxo-8-(pentyloxy)-3-quinolinecarboxamide (JTE907) were inverse agonists in cyclase but low efficacy agonists in arrestin recruitment assays. Thus, CB2 receptor ligands display strong and varied functional selectivity at both pathways. Therefore, extreme care must be exercised when using these compounds to infer the role of CB2 receptors in vivo.
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Affiliation(s)
- Amey Dhopeshwarkar
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana
| | - Ken Mackie
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana
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Fitzgibbon M, Finn DP, Roche M. High Times for Painful Blues: The Endocannabinoid System in Pain-Depression Comorbidity. Int J Neuropsychopharmacol 2015; 19:pyv095. [PMID: 26342110 PMCID: PMC4815466 DOI: 10.1093/ijnp/pyv095] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 08/17/2015] [Indexed: 01/06/2023] Open
Abstract
Depression and pain are two of the most debilitating disorders worldwide and have an estimated cooccurrence of up to 80%. Comorbidity of these disorders is more difficult to treat, associated with significant disability and impaired health-related quality of life than either condition alone, resulting in enormous social and economic cost. Several neural substrates have been identified as potential mediators in the association between depression and pain, including neuroanatomical reorganization, monoamine and neurotrophin depletion, dysregulation of the hypothalamo-pituitary-adrenal axis, and neuroinflammation. However, the past decade has seen mounting evidence supporting a role for the endogenous cannabinoid (endocannabinoid) system in affective and nociceptive processing, and thus, alterations in this system may play a key role in reciprocal interactions between depression and pain. This review will provide an overview of the preclinical evidence supporting an interaction between depression and pain and the evidence supporting a role for the endocannabinoid system in this interaction.
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Affiliation(s)
| | | | - Michelle Roche
- Physiology (Ms Fitzgibbon and Dr Roche), and Pharmacology and Therapeutics (Dr Finn), School of Medicine, Galway Neuroscience Centre and Centre for Pain Research (Ms Fitzgibbon, Dr Finn, and Dr Roche), National Centre for Biomedical Engineering Science, National University of Ireland Galway, Ireland.
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Dong M, Lu Y, Zou Z, Yang H. Monoacylglycerol lipase inhibitor protects primary cultured neurons against homocysteine-induced impairments in rat caudate nucleus through COX-2 signaling. Life Sci 2015; 138:64-71. [PMID: 25818189 DOI: 10.1016/j.lfs.2015.03.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 03/01/2015] [Accepted: 03/11/2015] [Indexed: 10/23/2022]
Abstract
AIMS URB602 is a selective inhibitor of monoacylglycerol lipase (MAGL), a serine hydrolase involved in the biological deactivation of the endocannabinoid 2-arachidonoyl glycerol (2-AG). It has been described that URB602 significantly enhances depolarization-induced increases in 2-AG. A high level of homocysteine (Hcy) is a modifiable risk factor for developing Alzheimer's disease (AD). The aim of this study was to investigate the protective effects of URB602 on Hcy-induced impairments underlying its cellular and molecular mechanism in primary cultured caudate nucleus (CN) neurons. MAIN METHODS The expressions of cyclooxygenase-2 (COX-2), ERK1/2, NF-κB and IκB-α as well as cleaved caspase-3 and p-Bcl-2 in Hcy-, URB602 or SR1 (a selective inhibitor of CB1 receptor)-treated primary cultured neurons in CN were measured by immunoblotting technique and neurotoxicity assays were performed by using Hoechst staining. KEY FINDINGS The MAGL inhibitor URB602 exerted a neuroprotective effect on Hcy-induced impairment through suppression of cyclooxygenase-2 (COX-2) elevation and ERK1/2 and NF-κB phosphorylation as well as suppressions of IκB-α degradation in a CB1 receptor-dependent way. Moreover, anti-neuronal impairments of URB602 were mediated by modulating down-regulation of cleaved caspase-3 expression and up-regulation of p-Bcl-2 expression in a CB1 receptor-dependent manner in primary cultured CN neurons. SIGNIFICANCE These data suggest that the MAGL inhibitor is a promising therapeutic target for some neurodegenerative disorders, such as AD, via the COX-2 signaling pathway.
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Affiliation(s)
- Manman Dong
- Department of Physiology and Pathophysiology, College of Medical Sciences, China Three Gorges University, 443002 Yichang, Hubei, PR China
| | - Yongli Lu
- Department of Physiology and Pathophysiology, College of Medical Sciences, China Three Gorges University, 443002 Yichang, Hubei, PR China
| | - Ziliang Zou
- Department of Physiology and Pathophysiology, College of Medical Sciences, China Three Gorges University, 443002 Yichang, Hubei, PR China
| | - Hongwei Yang
- Department of Physiology and Pathophysiology, College of Medical Sciences, China Three Gorges University, 443002 Yichang, Hubei, PR China.
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Abstract
The physiological and pathophysiological functions of the endocannabinoid system have been studied extensively using transgenic and targeted knockout mouse models. The first gene deletions of the cannabinoid CB(1) receptor were described in the late 1990s, soon followed by CB(2) and FAAH mutations in early 2000. These mouse models helped to elucidate the fundamental role of endocannabinoids as retrograde transmitters in the CNS and in the discovery of many unexpected endocannabinoid functions, for example, in the skin, bone and liver. We now have knockout mouse models for almost every receptor and enzyme of the endocannabinoid system. Conditional mutant mice were mostly developed for the CB(1) receptor, which is widely expressed on many different neurons, astrocytes and microglia, as well as on many cells outside the CNS. These mouse strains include "floxed" CB(1) alleles and mice with a conditional re-expression of CB(1). The availability of these mice made it possible to decipher the function of CB(1) in specific neuronal circuits and cell populations or to discriminate between central and peripheral effects. Many of the genetic mouse models were also used in combination with viral expression systems. The purpose of this review is to provide a comprehensive overview of the existing genetic models and to summarize some of the most important discoveries that were made with these animals.
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MESH Headings
- Amidohydrolases/genetics
- Amidohydrolases/metabolism
- Animals
- Endocannabinoids/genetics
- Endocannabinoids/metabolism
- Gene Deletion
- Gene Expression Regulation
- Genotype
- Humans
- Hydrolysis
- Mice, Knockout
- Mice, Mutant Strains
- Monoacylglycerol Lipases/genetics
- Monoacylglycerol Lipases/metabolism
- Mutation
- Phenotype
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB2/genetics
- Receptor, Cannabinoid, CB2/metabolism
- Signal Transduction/genetics
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Affiliation(s)
- Andreas Zimmer
- Institute of Molecular Psychiatry, University of Bonn, Bonn, Germany.
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Dhopeshwarkar A, Mackie K. CB2 Cannabinoid receptors as a therapeutic target-what does the future hold? Mol Pharmacol 2014; 86:430-7. [PMID: 25106425 DOI: 10.1124/mol.114.094649] [Citation(s) in RCA: 186] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The past decades have seen an exponential rise in our understanding of the endocannabinoid system, comprising CB1 and CB2 cannabinoid receptors, endogenous cannabinoids (endocannabinoids), and the enzymes that synthesize and degrade endocannabinoids. The primary focus of this review is the CB2 receptor. CB2 receptors have been the subject of considerable attention, primarily due to their promising therapeutic potential for treating various pathologies while avoiding the adverse psychotropic effects that can accompany CB1 receptor-based therapies. With the appreciation that CB2-selective ligands show marked functional selectivity, there is a renewed opportunity to explore this promising area of research from both a mechanistic as well as a therapeutic perspective. In this review, we summarize our present knowledge of CB2 receptor signaling, localization, and regulation. We discuss the availability of genetic tools (and their limitations) to study CB2 receptors and also provide an update on preclinical data on CB2 agonists in pain models. Finally, we suggest possible reasons for the failure of CB2 ligands in clinical pain trials and offer possible ways to move the field forward in a way that can help reconcile the inconsistencies between preclinical and clinical data.
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Affiliation(s)
- Amey Dhopeshwarkar
- Department of Psychological and Brain Sciences and Gill Center, Indiana University, Bloomington, Indiana
| | - Ken Mackie
- Department of Psychological and Brain Sciences and Gill Center, Indiana University, Bloomington, Indiana
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CB2 receptor agonism reverses MK-801-induced disruptions of prepulse inhibition in mice. Psychopharmacology (Berl) 2014; 231:3071-87. [PMID: 24705902 DOI: 10.1007/s00213-014-3481-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 01/30/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE Whilst cannabinoid CB2 receptors were thought to exist predominantly in immune cells in the periphery, the recent discovery of CB2 receptors in the brain has led to an increased interest in the role of these central CB2 receptors. Several studies have reported an association with CB2 receptors and schizophrenia. Sensorimotor gating deficits occur in schizophrenia patients and can be induced in animals using psychotomimetic drugs such as N-methyl-D-aspartate (NMDA) receptor antagonists. OBJECTIVES The aim of this study was to investigate the effect of CB2 ligands on sensorimotor gating, either alone, or on sensorimotor gating deficits induced by the NMDA receptor antagonist MK-801 in mice. METHOD The effects of CB2 receptor ligands on prepulse inhibition (PPI), an operational measure of sensorimotor gating, alone or when administrated in combination with MK-801, in Balb-C mice were evaluated. RESULTS The CB2 receptor agonist JWH015 had no significant effect on PPI alone but reversed disruptions in PPI induced by MK-801. This effect was blocked by co-administration of the CB2 receptor antagonist AM630, but not by co-administration of the CB1 receptor antagonist AM251, indicating a CB2-mediated effect. The mixed CB1/CB2 receptor agonist JWH203 was partially able to reverse MK-801-induced PPI disruptions. Neither the CB2 receptor antagonist AM630 nor the CB1 receptor antagonist AM251 had any significant effect alone or on MK-801-induced disruptions in PPI. CONCLUSIONS CB2 receptor agonism reversed MK-801 disruptions in sensorimotor gating deficits in mice, indicating that CB2 agonism may have a protective effect against aspects of drug-induced psychosis.
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Detection of cannabinoid receptors CB1 and CB2 within basal ganglia output neurons in macaques: changes following experimental parkinsonism. Brain Struct Funct 2014; 220:2721-38. [PMID: 24972960 PMCID: PMC4549378 DOI: 10.1007/s00429-014-0823-8] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 06/10/2014] [Indexed: 11/21/2022]
Abstract
Although type 1 cannabinoid receptors (CB1Rs) are expressed abundantly throughout the brain, the presence of type 2 cannabinoid receptors (CB2Rs) in neurons is still somewhat controversial. Taking advantage of newly designed CB1R and CB2R mRNA riboprobes, we demonstrate by PCR and in situ hybridization that transcripts for both cannabinoid receptors are present within labeled pallidothalamic-projecting neurons of control and MPTP-treated macaques, whereas the expression is markedly reduced in dyskinetic animals. Moreover, an in situ proximity ligation assay was used to qualitatively assess the presence of CB1Rs and CB2Rs, as well as CB1R–CB2R heteromers within basal ganglia output neurons in all animal groups (control, parkinsonian and dyskinetic macaques). A marked reduction in the number of CB1Rs, CB2Rs and CB1R–CB2R heteromers was found in dyskinetic animals, mimicking the observed reduction in CB1R and CB2R mRNA expression levels. The fact that chronic levodopa treatment disrupted CB1R–CB2R heteromeric complexes should be taken into consideration when designing new drugs acting on cannabinoid receptor heteromers.
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Davis MP. Cannabinoids in pain management: CB1, CB2 and non-classic receptor ligands. Expert Opin Investig Drugs 2014; 23:1123-40. [PMID: 24836296 DOI: 10.1517/13543784.2014.918603] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Commercially available cannabinoids are subject to psychotomimetic and addiction (cannabinomimetic) adverse effects largely through activation of the cannabinoid 1 receptor (CB1r). The available commercial cannabinoids have a narrow therapeutic index. Recently developed peripherally restricted cannabinoids, regionally administered cannabinoids, bifunctional cannabinoid ligands and cannabinoid enzyme inhibitors, endocannabinoids, which do not interact with classic cannabinoid receptors (CB1r and CB2r), cannabinoid receptor antagonists and selective CB1r agonists hold promise as analgesics. AREAS COVERED This author provides a review of the current investigational cannabinoids currently in development for pain management. The author also provides their perspective on the future of the field. EXPERT OPINION Regional and peripherally restricted cannabinoids will reduce cannabinomimetic side effects. Spinal cannabinoids may increase the therapeutic index by limiting the dose necessary for response and minimize drugs exposure to supraspinal sites where cannabinomimetic side effects originate. Cannabinoid bifunctional ligands should be further explored. The combination of a CB2r agonist with a transient receptor potential vanilloid (TRPV-1) antagonist may improve the therapeutic index of the CB2r agonist. Enzyme inhibitors plus TRPV-1 blockers should be further explored. The development of analgesic tolerance with enzyme inhibitors and the pronociceptive effects of prostamides limit the benefits to cannabinoid hydrolyzing enzyme inhibitors. Most clinically productive development of cannabinoids over the next 5 years will be in the area of selective CB2r agonists. These agents will be tested in various inflammatory, osteoarthritis and neuropathic pains.
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Affiliation(s)
- Mellar P Davis
- The Cleveland Clinic Taussig Cancer Institute, The Harry R. Horvitz Center for Palliative Medicine, Department of Solid Tumor Oncology , 9500 Euclid Avenue R35, Cleveland, OH 44195 , USA +1 216 445 4622 ; +1 216 636 3179 ;
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den Boon FS, Chameau P, Houthuijs K, Bolijn S, Mastrangelo N, Kruse CG, Maccarrone M, Wadman WJ, Werkman TR. Endocannabinoids produced upon action potential firing evoke a Cl(-) current via type-2 cannabinoid receptors in the medial prefrontal cortex. Pflugers Arch 2014; 466:2257-68. [PMID: 24671573 DOI: 10.1007/s00424-014-1502-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 03/06/2014] [Accepted: 03/12/2014] [Indexed: 12/13/2022]
Abstract
The functional presence of type-2 cannabinoid receptors (CB2Rs) in layer II/III pyramidal neurons of the rat medial prefrontal cortex (mPFC) was recently demonstrated. In the present study, we show that the application of the endocannabinoids (eCBs) 2-arachidonoylglycerol (2-AG) and methanandamide [a stable analog of the eCB anandamide (AEA)] can activate CB2Rs of mPFC layer II/III pyramidal neurons, which subsequently induces a Cl(-) current. In addition, we show that action potential (AP) firing evoked by 20-Hz current injections results in an eCB-mediated opening of Cl(-) channels via CB2R activation. This AP-evoked synthesis of eCBs is dependent on the Ca(2+) influx through N-type voltage-gated calcium channels. Our results indicate that 2-AG is the main eCB involved in this process. Finally, we demonstrate that under physiologically relevant intracellular Cl(-) conditions, 20-Hz AP firing leads to a CB2R-dependent reduction in neuronal excitability. Altogether, our data indicate that eCBs released upon action potential firing can modulate, through CB2R activation, neuronal activity in the mPFC. We discuss how this may be a mechanism to prevent excessive neuronal firing.
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Affiliation(s)
- Femke S den Boon
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
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Murataeva N, Straiker A, Mackie K. Parsing the players: 2-arachidonoylglycerol synthesis and degradation in the CNS. Br J Pharmacol 2014; 171:1379-91. [PMID: 24102242 PMCID: PMC3954479 DOI: 10.1111/bph.12411] [Citation(s) in RCA: 160] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 08/29/2013] [Accepted: 09/08/2013] [Indexed: 12/17/2022] Open
Abstract
UNLABELLED The endogenous cannabinoid signalling system, composed of endogenous cannabinoids, cannabinoid receptors and the enzymes that synthesize and degrade the endogenous cannabinoids, is much more complex than initially conceptualized. 2-Arachidonoylglycerol (2-AG) is the most abundant endocannabinoid and plays a major role in CNS development and synaptic plasticity. Over the past decade, many key players in 2-AG synthesis and degradation have been identified and characterized. Most 2-AG is synthesized from membrane phospholipids via sequential activation of a phospholipase Cβ and a diacylglycerol lipase, although other pathways may contribute in specialized settings. 2-AG breakdown is more complicated with at least eight different enzymes participating. These enzymes can either degrade 2-AG into its components, arachidonic acid and glycerol, or transform 2-AG into highly bioactive signal molecules. The implications of the precise temporal and spatial control of the expression and function of these pleiotropic metabolizing enzymes have only recently come to be appreciated. In this review, we will focus on the primary organization of the synthetic and degradative pathways of 2-AG and then discuss more recent findings and their implications, with an eye towards the biological and therapeutic implications of manipulating 2-AG synthesis and metabolism. LINKED ARTICLES This article is part of a themed section on Cannabinoids 2013. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-6.
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Affiliation(s)
- N Murataeva
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana UniversityBloomington, IN, USA
| | - A Straiker
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana UniversityBloomington, IN, USA
| | - K Mackie
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana UniversityBloomington, IN, USA
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Ignatowska-Jankowska BM, Muldoon PP, Lichtman AH, Damaj MI. The cannabinoid CB2 receptor is necessary for nicotine-conditioned place preference, but not other behavioral effects of nicotine in mice. Psychopharmacology (Berl) 2013; 229:591-601. [PMID: 23652588 PMCID: PMC4042856 DOI: 10.1007/s00213-013-3117-6] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 04/10/2013] [Indexed: 11/30/2022]
Abstract
RATIONALE Whereas cannabinoid CB1 receptors have long been known to contribute to the rewarding effects and dependence liability of many drugs of abuse, recent studies have implicated the involvement of cannabinoid CB2 receptors. OBJECTIVE Here, we evaluated the role of CB2 receptors in the rewarding properties of nicotine, as assessed in the conditioned place preference (CPP) paradigm and mecamylamine-precipitated withdrawal in nicotine dependent mice. METHODS Using complementary pharmacological and genetic approaches, we investigated the involvement of CB2 receptors in nicotine- and cocaine-induced CPP in mice and mecamylamine-precipitated withdrawal in nicotine-dependent mice. We also determined whether deletion of CB2 receptors affects nicotine-induced hypothermia and hypoalgesia. RESULTS Nicotine-induced (0.5 mg/kg) CPP was completely blocked by selective CB2 antagonist, SR144528 (3 mg/kg) in wild-type mice, and was absent in CB2 (-/-) mice. Conversely, the CB2 receptor agonist, O-1966 (1, 3, 5, 10, 20 mg/kg) given in combination with a subthreshold dose of nicotine (0.1 mg/kg) elicited a place preference. In contrast, O-1966 (20 mg/kg) blocked cocaine (10 mg/kg)-induced CPP in wild type mice, while CB2 (-/-) mice showed unaltered cocaine CPP. CB2 (+/+) and (-/-) nicotine-dependent mice showed almost identical precipitated withdrawal responses and deletion of CB2 receptor did not alter acute somatic effects of nicotine. CONCLUSIONS Collectively, these results indicate that CB2 receptors are required for nicotine-induced CPP in the mouse, while it is not involved in nicotine withdrawal or acute effects of nicotine. Moreover, these results suggest that CB2 receptors play opposing roles in nicotine- and cocaine-induced CPP.
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Affiliation(s)
- Bogna M Ignatowska-Jankowska
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA,
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Svízenská IH, Brázda V, Klusáková I, Dubový P. Bilateral changes of cannabinoid receptor type 2 protein and mRNA in the dorsal root ganglia of a rat neuropathic pain model. J Histochem Cytochem 2013; 61:529-47. [PMID: 23657829 DOI: 10.1369/0022155413491269] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cannabinoid receptor type 2 (CB2R) plays a critical role in nociception. In contrast to cannabinoid receptor type 1 ligands, CB2R agonists do not produce undesirable central nervous system effects and thus promise to treat neuropathic pain that is often resistant to medical therapy. In the study presented here, we evaluated the bilateral distribution of the CB2R protein and messenger RNA (mRNA) in rat dorsal root ganglia (DRG) after unilateral peripheral nerve injury using immunohistochemistry, western blot, and in situ hybridization analysis. Unilateral chronic constriction injury (CCI) of the sciatic nerve induced neuropathic pain behavior and bilateral elevation of both CB2R protein and mRNA in lumbar L4-L5 as well as cervical C7-C8 DRG when compared with naive animals. CB2R protein and mRNA were increased not only in DRG neurons but also in satellite glial cells. The fact that changes appear bilaterally and (albeit at a lower level) even in the remote cervical DRG can be related to propagation of neuroinflammation alongside the neuraxis and to the neuroprotective effects of CB2R.
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Seely KA, Brents LK, Franks LN, Rajasekaran M, Zimmerman SM, Fantegrossi WE, Prather PL. AM-251 and rimonabant act as direct antagonists at mu-opioid receptors: implications for opioid/cannabinoid interaction studies. Neuropharmacology 2012; 63:905-15. [PMID: 22771770 DOI: 10.1016/j.neuropharm.2012.06.046] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 06/04/2012] [Accepted: 06/22/2012] [Indexed: 11/16/2022]
Abstract
Mu-opioid and CB1-cannabinoid agonists produce analgesia; however, adverse effects limit use of drugs in both classes. Additive or synergistic effects resulting from concurrent administration of low doses of mu- and CB1-agonists may produce analgesia with fewer side effects. Synergism potentially results from interaction between mu-opioid receptors (MORs) and CB1 receptors (CB1Rs). AM-251 and rimonabant are CB1R antagonist/inverse agonists employed to validate opioid-cannabinoid interactions, presumed to act selectively at CB1Rs. Therefore, the potential for direct action of these antagonists at MORs is rarely considered. This study determined if AM-251 and/or rimonabant directly bind and modulate the function of MORs. Surprisingly, AM-251 and rimonabant, but not a third CB1R inverse agonist AM-281, bind with mid-nanomolar affinity to human MORs with a rank order of affinity (K(i)) of AM-251 (251 nM) > rimonabant (652 nM) > AM281 (2135 nM). AM-251 and rimonabant, but not AM-281, also competitively antagonize morphine induced G-protein activation in CHO-hMOR cell homogenates (K(b) = 719 or 1310 nM, respectively). AM-251 and rimonabant block morphine inhibition of cAMP production, while only AM-251 elicits cAMP rebound in CHO-hMOR cells chronically exposed to morphine. AM-251 and rimonabant (10 mg/kg) attenuate morphine analgesia, whereas the same dose of AM-281 produces little effect. Therefore, in addition to high CB1R affinity, AM-251 and rimonabant bind to MORs with mid-nanomolar affinity and at higher doses may affect morphine analgesia via direct antagonism at MORs. Such CB1-independent of these antagonists effects may contribute to reported inconsistencies when CB1/MOR interactions are examined via pharmacological methods in CB1-knockout versus wild-type mice.
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Affiliation(s)
- Kathryn A Seely
- Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, 4301 W. Markham Street, Little Rock, AR 72205, USA.
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