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Briand-Mésange F, Gennero I, Salles J, Trudel S, Dahan L, Ausseil J, Payrastre B, Salles JP, Chap H. From Classical to Alternative Pathways of 2-Arachidonoylglycerol Synthesis: AlterAGs at the Crossroad of Endocannabinoid and Lysophospholipid Signaling. Molecules 2024; 29:3694. [PMID: 39125098 PMCID: PMC11314389 DOI: 10.3390/molecules29153694] [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: 06/21/2024] [Revised: 07/27/2024] [Accepted: 08/02/2024] [Indexed: 08/12/2024] Open
Abstract
2-arachidonoylglycerol (2-AG) is the most abundant endocannabinoid (EC), acting as a full agonist at both CB1 and CB2 cannabinoid receptors. It is synthesized on demand in postsynaptic membranes through the sequential action of phosphoinositide-specific phospholipase Cβ1 (PLCβ1) and diacylglycerol lipase α (DAGLα), contributing to retrograde signaling upon interaction with presynaptic CB1. However, 2-AG production might also involve various combinations of PLC and DAGL isoforms, as well as additional intracellular pathways implying other enzymes and substrates. Three other alternative pathways of 2-AG synthesis rest on the extracellular cleavage of 2-arachidonoyl-lysophospholipids by three different hydrolases: glycerophosphodiesterase 3 (GDE3), lipid phosphate phosphatases (LPPs), and two members of ecto-nucleotide pyrophosphatase/phosphodiesterases (ENPP6-7). We propose the names of AlterAG-1, -2, and -3 for three pathways sharing an ectocellular localization, allowing them to convert extracellular lysophospholipid mediators into 2-AG, thus inducing typical signaling switches between various G-protein-coupled receptors (GPCRs). This implies the critical importance of the regioisomerism of both lysophospholipid (LPLs) and 2-AG, which is the object of deep analysis within this review. The precise functional roles of AlterAGs are still poorly understood and will require gene invalidation approaches, knowing that both 2-AG and its related lysophospholipids are involved in numerous aspects of physiology and pathology, including cancer, inflammation, immune defenses, obesity, bone development, neurodegeneration, or psychiatric disorders.
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Affiliation(s)
- Fabienne Briand-Mésange
- Infinity-Toulouse Institute for Infectious and Inflammatory Diseases, University of Toulouse, INSERM, CNRS, Paul Sabatier University, 31059 Toulouse, France; (F.B.-M.); (I.G.); (J.S.); (S.T.); (J.A.); (J.-P.S.)
| | - Isabelle Gennero
- Infinity-Toulouse Institute for Infectious and Inflammatory Diseases, University of Toulouse, INSERM, CNRS, Paul Sabatier University, 31059 Toulouse, France; (F.B.-M.); (I.G.); (J.S.); (S.T.); (J.A.); (J.-P.S.)
- Centre Hospitalier Universitaire de Toulouse, Service de Biochimie, Institut Fédératif de Biologie, 31059 Toulouse, France
| | - Juliette Salles
- Infinity-Toulouse Institute for Infectious and Inflammatory Diseases, University of Toulouse, INSERM, CNRS, Paul Sabatier University, 31059 Toulouse, France; (F.B.-M.); (I.G.); (J.S.); (S.T.); (J.A.); (J.-P.S.)
- Centre Hospitalier Universitaire de Toulouse, Service de Psychiatrie D’urgences, de Crise et de Liaison, Institut des Handicaps Neurologiques, Psychiatriques et Sensoriels, 31059 Toulouse, France
| | - Stéphanie Trudel
- Infinity-Toulouse Institute for Infectious and Inflammatory Diseases, University of Toulouse, INSERM, CNRS, Paul Sabatier University, 31059 Toulouse, France; (F.B.-M.); (I.G.); (J.S.); (S.T.); (J.A.); (J.-P.S.)
- Centre Hospitalier Universitaire de Toulouse, Service de Biochimie, Institut Fédératif de Biologie, 31059 Toulouse, France
| | - Lionel Dahan
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062 Toulouse, France;
| | - Jérôme Ausseil
- Infinity-Toulouse Institute for Infectious and Inflammatory Diseases, University of Toulouse, INSERM, CNRS, Paul Sabatier University, 31059 Toulouse, France; (F.B.-M.); (I.G.); (J.S.); (S.T.); (J.A.); (J.-P.S.)
- Centre Hospitalier Universitaire de Toulouse, Service de Biochimie, Institut Fédératif de Biologie, 31059 Toulouse, France
| | - Bernard Payrastre
- I2MC-Institute of Metabolic and Cardiovascular Diseases, INSERM UMR1297 and University of Toulouse III, 31400 Toulouse, France;
- Centre Hospitalier Universitaire de Toulouse, Laboratoire d’Hématologie, 31400 Toulouse, France
| | - Jean-Pierre Salles
- Infinity-Toulouse Institute for Infectious and Inflammatory Diseases, University of Toulouse, INSERM, CNRS, Paul Sabatier University, 31059 Toulouse, France; (F.B.-M.); (I.G.); (J.S.); (S.T.); (J.A.); (J.-P.S.)
- Centre Hospitalier Universitaire de Toulouse, Unité d’Endocrinologie et Maladies Osseuses, Hôpital des Enfants, 31059 Toulouse, France
| | - Hugues Chap
- Infinity-Toulouse Institute for Infectious and Inflammatory Diseases, University of Toulouse, INSERM, CNRS, Paul Sabatier University, 31059 Toulouse, France; (F.B.-M.); (I.G.); (J.S.); (S.T.); (J.A.); (J.-P.S.)
- Académie des Sciences, Inscriptions et Belles Lettres de Toulouse, Hôtel d’Assézat, 31000 Toulouse, France
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Dudok B, Fan LZ, Farrell JS, Malhotra S, Homidan J, Kim DK, Wenardy C, Ramakrishnan C, Li Y, Deisseroth K, Soltesz I. Retrograde endocannabinoid signaling at inhibitory synapses in vivo. Science 2024; 383:967-970. [PMID: 38422134 PMCID: PMC10921710 DOI: 10.1126/science.adk3863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 01/24/2024] [Indexed: 03/02/2024]
Abstract
Endocannabinoid (eCB)-mediated suppression of inhibitory synapses has been hypothesized, but this has not yet been demonstrated to occur in vivo because of the difficulty in tracking eCB dynamics and synaptic plasticity during behavior. In mice navigating a linear track, we observed location-specific eCB signaling in hippocampal CA1 place cells, and this was detected both in the postsynaptic membrane and the presynaptic inhibitory axons. All-optical in vivo investigation of synaptic responses revealed that postsynaptic depolarization was followed by a suppression of inhibitory synaptic potentials. Furthermore, interneuron-specific cannabinoid receptor deletion altered place cell tuning. Therefore, rapid, postsynaptic, activity-dependent eCB signaling modulates inhibitory synapses on a timescale of seconds during behavior.
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Affiliation(s)
- Barna Dudok
- Departments of Neurology and Neuroscience, Baylor College of Medicine; Houston, TX, 77030, USA
- Department of Neurosurgery, Stanford University; Stanford, CA, 94305, USA
| | - Linlin Z. Fan
- Department of Bioengineering, Stanford University; Stanford, CA, 94305, USA
| | - Jordan S. Farrell
- Department of Neurosurgery, Stanford University; Stanford, CA, 94305, USA
- F.M. Kirby Neurobiology Center and Rosamund Stone Zander Translational Neuroscience Center, Boston Children’s Hospital; Boston, MA, 02115, USA
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School; Boston, MA, 02115, USA
| | - Shreya Malhotra
- Department of Neurosurgery, Stanford University; Stanford, CA, 94305, USA
| | - Jesslyn Homidan
- Department of Neurosurgery, Stanford University; Stanford, CA, 94305, USA
| | - Doo Kyung Kim
- Department of Bioengineering, Stanford University; Stanford, CA, 94305, USA
| | - Celestine Wenardy
- Department of Bioengineering, Stanford University; Stanford, CA, 94305, USA
| | - Charu Ramakrishnan
- Cracking the Neural Code (CNC) Program, Stanford University; Stanford, CA, 94305, USA
| | - Yulong Li
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University; Beijing, 100871, China
| | - Karl Deisseroth
- Department of Bioengineering, Stanford University; Stanford, CA, 94305, USA
- Department of Psychiatry and Behavioral Sciences, Stanford University; Stanford, CA, 94305, USA
- Howard Hughes Medical Institute; Stanford, CA, 94305, USA
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University; Stanford, CA, 94305, USA
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Asher MJ, McMullan HM, Dong A, Li Y, Thayer SA. A Complete Endocannabinoid Signaling System Modulates Synaptic Transmission between Human Induced Pluripotent Stem Cell-Derived Neurons. Mol Pharmacol 2023; 103:100-112. [PMID: 36379717 PMCID: PMC9881009 DOI: 10.1124/molpharm.122.000555] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 10/01/2022] [Accepted: 10/24/2022] [Indexed: 11/16/2022] Open
Abstract
The endocannabinoid system (ECS) modulates synaptic function to regulate many aspects of neurophysiology. It adapts to environmental changes and is affected by disease. Thus, the ECS presents an important target for therapeutic development. Despite recent interest in cannabinoid-based treatments, few preclinical studies are conducted in human systems. Human induced pluripotent stem cells (hiPSCs) provide one possible solution to this issue. However, it is not known if these cells have a fully functional ECS. Here, we show that hiPSC-derived neuron/astrocyte cultures exhibit a complete ECS. Using Ca2+ imaging and a genetically encoded endocannabinoid sensor, we demonstrate that they not only respond to exogenously applied cannabinoids but also produce and metabolize endocannabinoids. Synaptically driven [Ca2+]i spiking activity was inhibited (EC50 = 48 ± 13 nM) by the efficacious agonist [R(+)-[2,3-dihydro-5-methyl-3-[(morpholinyl)methyl]pyrolol [1,2,3-de]-1,4-benzoxazin-yl]-(1-naphthalenyl)methanone mesylate] (Win 55,212-2) and by the endogenous ligand 2-arachidonoyl glycerol (2-AG; EC50 = 2.0 ± 0.6 µm). The effects of Win 55212-2 were blocked by a CB1 receptor-selective antagonist. Δ9-Tetrahydrocannabinol acted as a partial agonist, maximally inhibiting synaptic activity by 47 ± 14% (EC50 = 1.4 ± 1.9 µm). Carbachol stimulated 2-AG production in a manner that was independent of Ca2+ and blocked by selective inhibition of diacylglycerol lipase. 2-AG returned to basal levels via a process mediated by monoacylglycerol lipase as indicated by slowed recovery in cultures treated with 4-[Bis(1,3-benzodioxol-5-yl)hydroxymethyl]-1-piperidinecarboxylic acid 4-nitrophenyl ester (JZL 184). Win 55,212-2 markedly desensitized CB1 receptor function following a 1-day exposure, whereas desensitization was incomplete following 7-day treatment with JZL 184. This human cell culture model is well suited for functional analysis of the ECS and as a platform for drug development. SIGNIFICANCE STATEMENT: Despite known differences between the human response to cannabinoids and that of other species, an in vitro human model demonstrating a fully functional endocannabinoid system has not been described. Human induced pluripotent stem cells (hiPSCs) can be obtained from skin samples and then reprogrammed into neurons for use in basic research and drug screening. Here, we show that hiPSC-derived neuronal cultures exhibit a complete endocannabinoid system suitable for mechanistic studies and drug discovery.
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Affiliation(s)
- Melissa J Asher
- Department of Pharmacology (M.J.A., H.M.M., S.A.T.), Graduate Program in Neuroscience (M.J.A., S.A.T.), and Molecular Pharmacology and Therapeutics Graduate Program (H.M.M., S.A.T.), University of Minnesota Medical School, Minneapolis, Minnesota; State Key Laboratory of Membrane Biology, Peking University School of Life Sciences (A.D., Y.L.), IDG/McGovern Institute for Brain Research (A.D., Y.L.), and Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies (A.D., Y.L.), Peking University, Beijing, China; and Chinese Institute for Brain Research, Beijing, China (Y.L.)
| | - Hannah M McMullan
- Department of Pharmacology (M.J.A., H.M.M., S.A.T.), Graduate Program in Neuroscience (M.J.A., S.A.T.), and Molecular Pharmacology and Therapeutics Graduate Program (H.M.M., S.A.T.), University of Minnesota Medical School, Minneapolis, Minnesota; State Key Laboratory of Membrane Biology, Peking University School of Life Sciences (A.D., Y.L.), IDG/McGovern Institute for Brain Research (A.D., Y.L.), and Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies (A.D., Y.L.), Peking University, Beijing, China; and Chinese Institute for Brain Research, Beijing, China (Y.L.)
| | - Ao Dong
- Department of Pharmacology (M.J.A., H.M.M., S.A.T.), Graduate Program in Neuroscience (M.J.A., S.A.T.), and Molecular Pharmacology and Therapeutics Graduate Program (H.M.M., S.A.T.), University of Minnesota Medical School, Minneapolis, Minnesota; State Key Laboratory of Membrane Biology, Peking University School of Life Sciences (A.D., Y.L.), IDG/McGovern Institute for Brain Research (A.D., Y.L.), and Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies (A.D., Y.L.), Peking University, Beijing, China; and Chinese Institute for Brain Research, Beijing, China (Y.L.)
| | - Yulong Li
- Department of Pharmacology (M.J.A., H.M.M., S.A.T.), Graduate Program in Neuroscience (M.J.A., S.A.T.), and Molecular Pharmacology and Therapeutics Graduate Program (H.M.M., S.A.T.), University of Minnesota Medical School, Minneapolis, Minnesota; State Key Laboratory of Membrane Biology, Peking University School of Life Sciences (A.D., Y.L.), IDG/McGovern Institute for Brain Research (A.D., Y.L.), and Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies (A.D., Y.L.), Peking University, Beijing, China; and Chinese Institute for Brain Research, Beijing, China (Y.L.)
| | - Stanley A Thayer
- Department of Pharmacology (M.J.A., H.M.M., S.A.T.), Graduate Program in Neuroscience (M.J.A., S.A.T.), and Molecular Pharmacology and Therapeutics Graduate Program (H.M.M., S.A.T.), University of Minnesota Medical School, Minneapolis, Minnesota; State Key Laboratory of Membrane Biology, Peking University School of Life Sciences (A.D., Y.L.), IDG/McGovern Institute for Brain Research (A.D., Y.L.), and Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies (A.D., Y.L.), Peking University, Beijing, China; and Chinese Institute for Brain Research, Beijing, China (Y.L.)
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Fauzan M, Oubraim S, Yu M, Glaser ST, Kaczocha M, Haj-Dahmane S. Fatty Acid-Binding Protein 5 Modulates Brain Endocannabinoid Tone and Retrograde Signaling in the Striatum. Front Cell Neurosci 2022; 16:936939. [PMID: 35875351 PMCID: PMC9302024 DOI: 10.3389/fncel.2022.936939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 06/15/2022] [Indexed: 12/14/2022] Open
Abstract
The endocannabinoid (eCB) anandamide (AEA) and 2-arachidonoylglycerol (2-AG) are endogenous lipid neurotransmitters that regulate an array of physiological functions, including pain, stress homeostasis, and reward. Fatty acid-binding protein 5 (FABP5) is a key modulator of intracellular eCB transport and inactivation. Recent evidence suggests that FABP5 controls synaptic 2-AG signaling at excitatory synapses in the dorsal raphe nucleus. However, it is currently not known whether this function extends to other brain areas. To address this, we first profiled eCB levels across several brain areas in FABP5 knockout mice and wild-type controls and report that FABP5 deletion elevates AEA levels in the striatum, prefrontal cortex, midbrain, and thalamus, as well as midbrain 2-AG levels. The expression of eCB biosynthetic and catabolic enzymes was largely unaltered in these regions, although minor sex and region-specific changes in the expression of 2-AG catabolic enzymes were observed in female FABP5 KO mice. Robust FABP5 expression was observed in the striatum, a region where both AEA and 2-AG control synaptic transmission. Deletion of FABP5 impaired tonic 2-AG and AEA signaling at striatal GABA synapses of medium spiny neurons, and blunted phasic 2-AG mediated short-term synaptic plasticity without altering CB1R expression or function. Collectively, these results support the role of FABP5 as a key regulator of eCB signaling at excitatory and inhibitory synapses in the brain.
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Affiliation(s)
- Mohammad Fauzan
- Department of Anesthesiology, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY, United States,Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, United States
| | - Saida Oubraim
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, United States
| | - Mei Yu
- Department of Anesthesiology, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY, United States
| | - Sherrye T. Glaser
- Department of Anesthesiology, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY, United States,Department of Biological Sciences, Kingsborough Community College, Brooklyn, NY, United States
| | - Martin Kaczocha
- Department of Anesthesiology, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY, United States,Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, United States,Martin Kaczocha
| | - Samir Haj-Dahmane
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, United States,University at Buffalo Neuroscience Program, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, United States,*Correspondence: Samir Haj-Dahmane
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5
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Winters BL, Vaughan CW. Mechanisms of endocannabinoid control of synaptic plasticity. Neuropharmacology 2021; 197:108736. [PMID: 34343612 DOI: 10.1016/j.neuropharm.2021.108736] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 07/27/2021] [Accepted: 07/28/2021] [Indexed: 01/13/2023]
Abstract
The endogenous cannabinoid transmitter system regulates synaptic transmission throughout the nervous system. Unlike conventional transmitters, specific stimuli induce synthesis of endocannabinoids (eCBs) in the postsynaptic neuron, and these travel backwards to modulate presynaptic inputs. In doing so, eCBs can induce short-term changes in synaptic strength and longer-term plasticity. While this eCB regulation is near ubiquitous, it displays major regional and synapse specific variations with different synapse specific forms of short-versus long-term plasticity throughout the brain. These differences are due to the plethora of pre- and postsynaptic mechanisms which have been implicated in eCB signalling, the intricacies of which are only just being realised. In this review, we shall describe the current understanding and highlight new advances in this area, with a focus on the retrograde action of eCBs at CB1 receptors (CB1Rs).
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Affiliation(s)
- Bryony Laura Winters
- Pain Management Research Institute, Kolling Institute of Medical Research, Northern Clinical School, University of Sydney at Royal North Shore Hospital, NSW, Australia.
| | - Christopher Walter Vaughan
- Pain Management Research Institute, Kolling Institute of Medical Research, Northern Clinical School, University of Sydney at Royal North Shore Hospital, NSW, Australia
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6
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Kaczocha M, Haj-Dahmane S. Mechanisms of endocannabinoid transport in the brain. Br J Pharmacol 2021; 179:4300-4310. [PMID: 33786823 DOI: 10.1111/bph.15469] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 03/22/2021] [Accepted: 03/24/2021] [Indexed: 12/14/2022] Open
Abstract
The endocannabinoids 2-arachidonoylglycerol (2-AG) and anandamide are among the best studied lipid messengers in the brain. By activating cannabinoid receptors in the CNS, endocannabinoids tune synaptic function, thereby influencing a variety of physiological and behavioural processes. Extensive research conducted over the last few decades has considerably enhanced our understanding of the molecular mechanisms and physiological functions of the endocannabinoid system. It is now well-established that endocannabinoids are synthesized by postsynaptic neurons and serve as retrograde messengers that suppress neurotransmitter release at central synapses. While the detailed mechanisms by which endocannabinoids gate synaptic function and behavioural processes are relatively well characterized, the mechanisms governing endocannabinoid transport at central synapses remain ill defined. Recently, several studies have begun to unravel the mechanisms governing intracellular and intercellular endocannabinoid transport. In this review, we will focus on new advances in the mechanisms of intracellular and synaptic endocannabinoid transport in the CNS.
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Affiliation(s)
- Martin Kaczocha
- Department of Anesthesiology, Stony Brook University, Stony Brook, New York, USA.,Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, USA
| | - Samir Haj-Dahmane
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, New York, USA.,Neuroscience Program, University at Buffalo, Buffalo, New York, USA
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Druggable Targets in Endocannabinoid Signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1274:177-201. [PMID: 32894511 DOI: 10.1007/978-3-030-50621-6_8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cannabis and cannabinoid-based extracts have long been utilized for their perceived therapeutic value, and support for the legalization of cannabis for medicinal purposes continues to increase worldwide. Since the discovery of Δ9-tetrahydrocannabinol (THC) as the primary psychoactive component of cannabis over 50 years ago, substantial effort has been directed toward detection of endogenous mediators of cannabinoid activity. The discovery of anandamide and 2-arachidonoylglycerol as two endogenous lipid mediators of cannabinoid-like effects (endocannabinoids) has inspired exponential growth in our understanding of this essential pathway, as well as the pathological conditions that result from dysregulated endocannabinoid signaling. This review examines current knowledge of the endocannabinoid system including metabolic enzymes involved in biosynthesis and degradation and their receptors, and evaluates potential druggable targets for therapeutic intervention.
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8
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Gestational alcohol exposure disrupts cognitive function and striatal circuits in adult offspring. Nat Commun 2020; 11:2555. [PMID: 32444624 PMCID: PMC7244532 DOI: 10.1038/s41467-020-16385-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 04/23/2020] [Indexed: 12/17/2022] Open
Abstract
Fetal alcohol exposure (FAE) is the leading preventable developmental cause of cognitive dysfunction. Even in the absence of binge drinking, alcohol consumption during pregnancy can leave offspring deficient. However, the mechanisms underlying these deficiencies are unknown. Using a mouse model of gestational ethanol exposure (GEE), we show increased instrumental lever-pressing and disruption of efficient habitual actions in adults, indicative of disrupted cognitive function. In vivo electrophysiology reveals disrupted action encoding in dorsolateral striatum (DLS) associated with altered habit learning. GEE mice exhibit decreased GABAergic transmission onto DLS projection neurons, including inputs from parvalbumin interneurons, and increased endocannabinoid tone. Chemogenetic activation of DLS parvalbumin interneurons reduces the elevated lever pressing of GEE mice. Pharmacologically increasing endocannabinoid tone mimics GEE effects on cognition and synaptic transmission. These findings show GEE induces long-lasting deficits in cognitive function that may contribute to human FAE, and identify potential mechanisms for future therapeutic targeting. Alcohol is the leading cause of preventable birth defects in the US, collectively referred to as Fetal Alcohol Spectrum Disorder. Here, the authors show that fetal alcohol exposure induces lasting neurophysiological changes in dorsal striatum that contribute to less efficient decision making.
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9
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Shonesy BC, Stephenson JR, Marks CR, Colbran RJ. Cyclic AMP-dependent protein kinase and D1 dopamine receptors regulate diacylglycerol lipase-α and synaptic 2-arachidonoyl glycerol signaling. J Neurochem 2020; 153:334-345. [PMID: 31985073 PMCID: PMC7367494 DOI: 10.1111/jnc.14972] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 01/07/2020] [Accepted: 01/21/2020] [Indexed: 01/11/2023]
Abstract
Brain endocannabinoids serve as retrograde neurotransmitters, being synthesized in post-synaptic neurons "on demand" and released to bind pre-synaptic cannabinoid receptors and suppress glutamatergic or GABAergic transmission. The most abundant brain endocannabinoid, 2 arachidonoyl glycerol (2-AG), is primarily synthesized by diacylglycerol lipase-α (DGLα), which is activated by poorly understood mechanisms in response to calcium influx following post-synaptic depolarization and/or the activation of Gq -coupled group 1 metabotropic glutamate receptors. However, the impact of other neurotransmitters and their downstream signaling pathways on synaptic 2-AG signaling has not been intensively studied. Here, we found that DGLα activity in membrane fractions from transfected HEK293T cells was significantly increased by in vitro phosphorylation using cyclic AMP-dependent protein kinase (PKA). Moreover, PKA directly phosphorylated DGLα at Ser798 in vitro. Elevation of cAMP levels in HEK293 cells expressing DGLα increased Ser798 phosphorylation, as detected using a phospho-Ser798-specific antibody, and enhanced DGLα activity; this in situ enhancement of DGLα activity was prevented by mutation of Ser798 to Ala. We investigated the impact of PKA on synaptic 2-AG mobilization in mouse striatal slices by manipulating D1-dopamine receptor (D1R) signaling and assessing depolarization-induced suppression of excitation, a DGLα- and 2-AG-dependent form of short-term synaptic depression. The magnitude of depolarization-enhanced suppression of excitation in direct pathway medium spiny neurons was increased by pre-incubation with a D1R agonist, and this enhancement was blocked by post-synaptic inhibition of PKA. Taken together, these findings provide new molecular insights into the complex mechanisms regulating synaptic endocannabinoid signaling.
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Affiliation(s)
- Brian C. Shonesy
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232-0615
| | - Jason R. Stephenson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232-0615
| | - Christian R. Marks
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232-0615
| | - Roger J. Colbran
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232-0615
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232-0615
- Vanderbilt Kennedy Center, Vanderbilt University, Nashville, TN 37232-0615
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10
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Franks AL, Berry KJ, DeFranco DB. Prenatal drug exposure and neurodevelopmental programming of glucocorticoid signalling. J Neuroendocrinol 2020; 32:e12786. [PMID: 31469457 PMCID: PMC6982551 DOI: 10.1111/jne.12786] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 08/25/2019] [Accepted: 08/27/2019] [Indexed: 12/21/2022]
Abstract
Prenatal neurodevelopment is dependent on precise functioning of multiple signalling pathways in the brain, including those mobilised by glucocorticoids (GC) and endocannabinoids (eCBs). Prenatal exposure to drugs of abuse, including opioids, alcohol, cocaine and cannabis, has been shown to not only impact GC signalling, but also alter functioning of the hypothalamic-pituitary-adrenal (HPA) axis. Such exposures can have long-lasting neurobehavioural consequences, including alterations in the stress response in the offspring. Furthermore, cannabis contains cannabinoids that signal via the eCB pathway, which is linked to some components of GC signalling in the adult brain. Given that GCs are frequently used in pregnancy to prevent complications of prematurity, and also that rates of cannabis use in pregnancy are increasing, the likelihood of foetal co-exposure to these compounds is high and may have additional implications for long-term neurodevelopment. Here, we present a discussion of GC signalling and the HPA axis, as well as the effects of prenatal drug exposure on these pathways and the stress response, and we explore the interactions between GC and EC signalling in the developing brain and potential for neurodevelopmental consequences.
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Affiliation(s)
- Alexis L Franks
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Kimberly J Berry
- Center for Neuroscience at the University of Pittsburgh, Pittsburgh, PA, USA
| | - Donald B DeFranco
- Center for Neuroscience at the University of Pittsburgh, Pittsburgh, PA, USA
- Department of Pharmacology and Chemical Biology and Neuroscience, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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11
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Andrade AK, Renda B, Murray JE. Cannabinoids, interoception, and anxiety. Pharmacol Biochem Behav 2019; 180:60-73. [DOI: 10.1016/j.pbb.2019.03.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 02/14/2019] [Accepted: 03/22/2019] [Indexed: 12/16/2022]
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12
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Marichal-Cancino BA, Fajardo-Valdez A, Ruiz-Contreras AE, Méndez-Díaz M, Prospéro-García O. Possible role of hippocampal GPR55 in spatial learning and memory in rats. Acta Neurobiol Exp (Wars) 2018. [DOI: 10.21307/ane-2018-001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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13
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Vogel E, Krabbe S, Gründemann J, Wamsteeker Cusulin JI, Lüthi A. Projection-Specific Dynamic Regulation of Inhibition in Amygdala Micro-Circuits. Neuron 2017; 91:644-51. [PMID: 27497223 DOI: 10.1016/j.neuron.2016.06.036] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 05/02/2016] [Accepted: 06/22/2016] [Indexed: 12/15/2022]
Abstract
Cannabinoid receptor type 1 (CB1R)-expressing CCK interneurons are key regulators of cortical circuits. Here we report that retrograde endocannabinoid signaling and CB1R-mediated regulation of inhibitory synaptic transmission onto basal amygdala principal neurons strongly depend on principal neuron projection target. Projection-specific asymmetries in the regulation of local inhibitory micro-circuits may contribute to the selective activation of distinct amygdala output pathways during behavioral changes.
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Affiliation(s)
- Elisabeth Vogel
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland; University of Basel, 4000 Basel, Switzerland
| | - Sabine Krabbe
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Jan Gründemann
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | | | - Andreas Lüthi
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland; University of Basel, 4000 Basel, Switzerland.
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14
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Melis M, Frau R, Kalivas PW, Spencer S, Chioma V, Zamberletti E, Rubino T, Parolaro D. New vistas on cannabis use disorder. Neuropharmacology 2017; 124:62-72. [PMID: 28373077 DOI: 10.1016/j.neuropharm.2017.03.033] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 03/28/2017] [Accepted: 03/29/2017] [Indexed: 02/06/2023]
Abstract
Cannabis sativa preparations are the most consumed illicit drugs for recreational purposes worldwide, and the number of people seeking treatment for cannabis use disorder has dramatically increased in the last decades. Due to the recent decriminalization or legalization of cannabis use in the Western Countries, we may predict that the number of people suffering from cannabis use disorder will increase. Despite the increasing number of cannabis studies over the past two decades, we have gaps of scientific knowledge pertaining to the neurobiological consequences of long-term cannabis use. Moreover, no specific treatments for cannabis use disorders are currently available. In this review, we explore new research that may help fill these gaps. We discuss and provide a solution to the experimental limitation of a lack of rodent models of THC self-administration, and the importance this model can play in understanding the neurobiology of relapse and in providing a biological rationale for potential therapeutic targets. We also focus our attention on glial cells, commenting on recent preclinical evidence suggesting that alterations in microglia and astrocytes might contribute to the detrimental effects associated with cannabis abuse. Finally, due to the worrisome prevalence rates of cannabis use during pregnancy, we highlight the associations between cannabis use disorders during pregnancy and congenital disorders, describing the possible neuronal basis of vulnerability at molecular and circuit level. This article is part of the Special Issue entitled "A New Dawn in Cannabinoid Neurobiology".
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Affiliation(s)
- Miriam Melis
- Dept. of Biomedical Sciences, Division of Neuroscience and Clinical Pharmacology, University of Cagliari, Italy
| | - Roberto Frau
- Dept. of Biomedical Sciences, Division of Neuroscience and Clinical Pharmacology, University of Cagliari, Italy
| | - Peter W Kalivas
- Department of Neuroscience, Medical University of South Carolina, SC, USA
| | - Sade Spencer
- Department of Neuroscience, Medical University of South Carolina, SC, USA
| | - Vivian Chioma
- Department of Neuroscience, Medical University of South Carolina, SC, USA
| | - Erica Zamberletti
- Dept. of Biotechnology and Life Sciences, University of Insubria, Busto Arsizio (VA), Italy
| | - Tiziana Rubino
- Dept. of Biotechnology and Life Sciences, University of Insubria, Busto Arsizio (VA), Italy
| | - Daniela Parolaro
- Dept. of Biotechnology and Life Sciences, University of Insubria, Busto Arsizio (VA), Italy; Zardi Gori Foundation, Milan, Italy.
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15
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Sánchez-Fuentes A, Marichal-Cancino BA, Méndez-Díaz M, Becerril-Meléndez AL, Ruiz-Contreras AE, Prospéro-Garcia O. mGluR1/5 activation in the lateral hypothalamus increases food intake via the endocannabinoid system. Neurosci Lett 2016; 631:104-108. [PMID: 27542344 DOI: 10.1016/j.neulet.2016.08.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 07/14/2016] [Accepted: 08/13/2016] [Indexed: 11/17/2022]
Abstract
Mounting evidence has shown that glutamatergic and endocannabinoid systems in the hypothalamus regulate mammalian food intake. Stimulation of hypothalamic mGluR1/5 and CB1 receptors induces hyperphagia suggesting a possible interaction between these systems to control food intake. In addition, synthesis of endocannabinoids has been reported after mGluR1/5 stimulation in the brain. The aim of this study was to examine the potential cannabinergic activity in the food intake induction by lateral hypothalamic stimulation of mGluR1/5. Wistar albino male rats received bilateral infusions in the lateral hypothalamus (LH) of: (i) vehicle; (ii) (RS)-2-Chloro-5-hidroxyphenylglycine (CHPG; mGluR1/5 agonist); (iii) 2-AG (CB1 endogenous agonist); (iv) AM251 (CB1 antagonist); (v) tetrahydrolipstatin (THL, 1.2μg; diacyl-glycerol lipase inhibitor); and (vi) combinations of CHPG + with the other aforementioned drugs. Food intake was evaluated the first two hours after drug administration. CHPG significantly increased food intake; whereas CHPG in combination with a dose of 2-AG (with no effects on food intake) greatly increased food ingestion compared to CHPG alone. The increase induced by CHPG in food intake was prevented with AM251 or THL. These results suggest that activation of mGluR1/5 in the lateral hypothalamus induces an orexigenic effect via activation of the endocannabinoid system.
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Affiliation(s)
- Asai Sánchez-Fuentes
- Grupo de Neurociencias, Laboratorio de Cannabinoides, Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico
| | - Bruno A Marichal-Cancino
- Grupo de Neurociencias, Laboratorio de Cannabinoides, Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico
| | - Mónica Méndez-Díaz
- Grupo de Neurociencias, Laboratorio de Cannabinoides, Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico
| | - Alline L Becerril-Meléndez
- Grupo de Neurociencias, Laboratorio de Cannabinoides, Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico
| | - Alejandra E Ruiz-Contreras
- Lab. Neurogenomica Cognitiva, Coord. Psicobiología y Neurociencias, Fac. Psicologia, Universidad Nacional Autónoma de México, México D.F., Mexico
| | - Oscar Prospéro-Garcia
- Grupo de Neurociencias, Laboratorio de Cannabinoides, Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico.
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16
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Cannabinoid Type 2 Receptors Mediate a Cell Type-Specific Plasticity in the Hippocampus. Neuron 2016; 90:795-809. [PMID: 27133464 DOI: 10.1016/j.neuron.2016.03.034] [Citation(s) in RCA: 203] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 01/20/2016] [Accepted: 03/18/2016] [Indexed: 02/07/2023]
Abstract
Endocannabinoids (eCBs) exert major control over neuronal activity by activating cannabinoid receptors (CBRs). The functionality of the eCB system is primarily ascribed to the well-documented retrograde activation of presynaptic CB1Rs. We find that action potential-driven eCB release leads to a long-lasting membrane potential hyperpolarization in hippocampal principal cells that is independent of CB1Rs. The hyperpolarization, which is specific to CA3 and CA2 pyramidal cells (PCs), depends on the activation of neuronal CB2Rs, as shown by a combined pharmacogenetic and immunohistochemical approach. Upon activation, they modulate the activity of the sodium-bicarbonate co-transporter, leading to a hyperpolarization of the neuron. CB2R activation occurred in a purely self-regulatory manner, robustly altered the input/output function of CA3 PCs, and modulated gamma oscillations in vivo. To conclude, we describe a cell type-specific plasticity mechanism in the hippocampus that provides evidence for the neuronal expression of CB2Rs and emphasizes their importance in basic neuronal transmission.
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17
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Abstract
Cannabis use has been reported to increase the risk of developing schizophrenia and to worsen symptoms of the illness. Both of these outcomes might be attributable to the disruption by cannabis of the endogenous cannabinoid system's spatiotemporal regulation of the inhibitory circuitry in the prefrontal cortex that is essential for core cognitive processes, such as working memory, which are impaired in schizophrenia. In the healthy brain, the endocannabinoid 2-arachidonylglycerol 1) is synthesized by diacylglycerol lipase in pyramidal neurons; 2) travels retrogradely to nearby inhibitory axon terminals that express the primary type 1 cannabinoid receptor (CB1R); 3) binds to CB1R, which inhibits gamma-aminobutyric acid release from the cholecystokinin-containing population of interneurons; and 4) is metabolized by either monoglyceride lipase, which is located in the inhibitory axon terminal, or by α-β-hydrolase domain 6, which is co-localized presynaptically with diacylglycerol lipase. Investigations of the endogenous cannabinoid system in the prefrontal cortex of subjects with schizophrenia have found evidence of higher metabolism of 2-arachidonylglycerol, as well as both greater CB1R receptor binding and lower levels of CB1R messenger RNA and protein. Current views on the potential pathogenesis of these alterations, including disturbances in the development of the endogenous cannabinoid system, are discussed. In addition, how interactions between these alterations in the endocannabinoid system and those in other inhibitory neurons in the prefrontal cortex in subjects with schizophrenia might increase the liability to adverse outcomes with cannabis use is considered.
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Affiliation(s)
- David W. Volk
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15213
| | - David A. Lewis
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15213,Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15213
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18
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Zhang L, Kolaj M, Renaud LP. Endocannabinoid 2-AG and intracellular cannabinoid receptors modulate a low-threshold calcium spike-induced slow depolarizing afterpotential in rat thalamic paraventricular nucleus neurons. Neuroscience 2016; 322:308-19. [PMID: 26924019 DOI: 10.1016/j.neuroscience.2016.02.047] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 02/18/2016] [Accepted: 02/19/2016] [Indexed: 12/01/2022]
Abstract
In rat paraventricular thalamic nucleus (PVT) neurons, activation of low-threshold calcium (Ca(2+)) channels triggers a low-threshold spike (LTS) which may be followed by slow afterpotentials that can dramatically influence action potential patterning. Using gluconate-based internal recording solutions, we investigated the properties of a LTS-induced slow afterdepolarization (sADP) observed in a subpopulation of PVT neurons recorded in brain slice preparations. This LTS-induced sADP required T-type Ca(2+) channel opening, exhibited variable magnitudes between neurons and a voltage dependency with a maximum near -50 mV. The area under the sADP remained stable during control monitoring, but displayed gradual suppression in media where strontium replaced Ca(2+). The sADP was suppressed following bath application of 2-APB or ML204, suggesting engagement of transient receptor potential canonical (TRPC)-like channels. Further investigation revealed a reversible suppression during bath applications of membrane permeable cannabinoid receptor (CBR) blockers rimonabant, AM630 or SR144528 suggesting the presence of both CB1Rs and CB2Rs. Similar results were achieved by intracellular, but not bath application of the membrane impermeant CB1R blocker hemopressin, suggesting an intracellular localization of CB1Rs. Data from pharmacologic manipulation of endocannabinoid biosynthetic pathways suggested 2-arachidonlyglycerol (2-AG) as the endogenous cannabinoid ligand, derived via hydrolysis of diacylglycerol (DAG), with the latter formed from the pathway involving phosphatidylcholine-specific phospholipase D and phosphatic acid phosphohydrolase. The sADP suppression observed during recordings with pipettes containing LY294002, a PI3-kinase inhibitor, suggested a role for PI3kinase in the translocation of these TRPC-like channels to the plasma membrane. Drug-induced attenuation of the availability of 2-AG influences the number of action potentials that surmount the LTS evoked in PVT neurons, implying an ongoing intracellular CBR modulation of neuronal excitability during LTS-induced bursting behavior.
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Affiliation(s)
- L Zhang
- Neuroscience Program, Ottawa Hospital Research Institute and Department of Medicine, University of Ottawa, 725 Parkdale Avenue, Ottawa, Ontario K1Y 4E9, Canada
| | - M Kolaj
- Neuroscience Program, Ottawa Hospital Research Institute and Department of Medicine, University of Ottawa, 725 Parkdale Avenue, Ottawa, Ontario K1Y 4E9, Canada
| | - L P Renaud
- Neuroscience Program, Ottawa Hospital Research Institute and Department of Medicine, University of Ottawa, 725 Parkdale Avenue, Ottawa, Ontario K1Y 4E9, Canada.
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19
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Abstract
In this review, I will consider the dual nature of Cannabis and cannabinoids. The duality arises from the potential and actuality of cannabinoids in the laboratory and clinic and the 'abuse' of Cannabis outside the clinic. The therapeutic areas currently best associated with exploitation of Cannabis-related medicines include pain, epilepsy, feeding disorders, multiple sclerosis and glaucoma. As with every other medicinal drug of course, the 'trick' will be to maximise the benefit and minimise the cost. After millennia of proximity and exploitation of the Cannabis plant, we are still playing catch up with an understanding of its potential influence for medicinal benefit.
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Affiliation(s)
- Stephen P H Alexander
- Life Sciences, University of Nottingham Medical School, Nottingham NG7 2UH, England, United Kingdom.
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20
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Hillard CJ. The Endocannabinoid Signaling System in the CNS: A Primer. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2015; 125:1-47. [PMID: 26638763 DOI: 10.1016/bs.irn.2015.10.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The purpose of this chapter is to provide an introduction to the mechanisms for the regulation of endocannabinoid signaling through CB1 cannabinoid receptors in the central nervous system. The processes involved in the synthesis and degradation of the two most well-studied endocannabinoids, 2-arachidonoylglycerol and N-arachidonylethanolamine are outlined along with information regarding the regulation of the proteins involved. Signaling mechanisms and pharmacology of the CB1 cannabinoid receptor are outlined, as is the paradigm of endocannabinoid/CB1 receptor regulation of neurotransmitter release. The reader is encouraged to appreciate the importance of the endocannabinoid/CB1 receptor signaling system in the regulation of synaptic activity in the brain.
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Affiliation(s)
- Cecilia J Hillard
- Neuroscience Research Center, and Department of Pharmacology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
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21
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Baggelaar MP, Chameau PJP, Kantae V, Hummel J, Hsu KL, Janssen F, van der Wel T, Soethoudt M, Deng H, den Dulk H, Allarà M, Florea BI, Di Marzo V, Wadman WJ, Kruse CG, Overkleeft HS, Hankemeier T, Werkman TR, Cravatt BF, van der Stelt M. Highly Selective, Reversible Inhibitor Identified by Comparative Chemoproteomics Modulates Diacylglycerol Lipase Activity in Neurons. J Am Chem Soc 2015; 137:8851-7. [PMID: 26083464 PMCID: PMC4773911 DOI: 10.1021/jacs.5b04883] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Diacylglycerol lipase (DAGL)-α and -β are enzymes responsible for the biosynthesis of the endocannabinoid 2-arachidonoylglycerol (2-AG). Selective and reversible inhibitors are required to study the function of DAGLs in neuronal cells in an acute and temporal fashion, but they are currently lacking. Here, we describe the identification of a highly selective DAGL inhibitor using structure-guided and a chemoproteomics strategy to characterize the selectivity of the inhibitor in complex proteomes. Key to the success of this approach is the use of comparative and competitive activity-based proteome profiling (ABPP), in which broad-spectrum and tailor-made activity-based probes are combined to report on the inhibition of a protein family in its native environment. Competitive ABPP with broad-spectrum fluorophosphonate-based probes and specific β-lactone-based probes led to the discovery of α-ketoheterocycle LEI105 as a potent, highly selective, and reversible dual DAGL-α/DAGL-β inhibitor. LEI105 did not affect other enzymes involved in endocannabinoid metabolism including abhydrolase domain-containing protein 6, abhydrolase domain-containing protein 12, monoacylglycerol lipase, and fatty acid amide hydrolase and did not display affinity for the cannabinoid CB1 receptor. Targeted lipidomics revealed that LEI105 concentration-dependently reduced 2-AG levels, but not anandamide levels, in Neuro2A cells. We show that cannabinoid CB1-receptor-mediated short-term synaptic plasticity in a mouse hippocampal slice model can be reduced by LEI105. Thus, we have developed a highly selective DAGL inhibitor and provide new pharmacological evidence to support the hypothesis that "on demand biosynthesis" of 2-AG is responsible for retrograde signaling.
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Affiliation(s)
- Marc P Baggelaar
- †Department of Bioorganic Synthesis, Leiden Institute of Chemistry, Leiden University, Leiden 2300 RA, The Netherlands
| | - Pascal J P Chameau
- ‡Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam 1000 GG, The Netherlands
| | - Vasudev Kantae
- §Division of Analytical Biosciences, Leiden Academic Centre for Drug Research, Leiden University, Leiden 2300 RA, The Netherlands
| | - Jessica Hummel
- †Department of Bioorganic Synthesis, Leiden Institute of Chemistry, Leiden University, Leiden 2300 RA, The Netherlands
| | - Ku-Lung Hsu
- ∥Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Freek Janssen
- †Department of Bioorganic Synthesis, Leiden Institute of Chemistry, Leiden University, Leiden 2300 RA, The Netherlands
| | - Tom van der Wel
- †Department of Bioorganic Synthesis, Leiden Institute of Chemistry, Leiden University, Leiden 2300 RA, The Netherlands
| | - Marjolein Soethoudt
- †Department of Bioorganic Synthesis, Leiden Institute of Chemistry, Leiden University, Leiden 2300 RA, The Netherlands
| | - Hui Deng
- †Department of Bioorganic Synthesis, Leiden Institute of Chemistry, Leiden University, Leiden 2300 RA, The Netherlands
| | - Hans den Dulk
- †Department of Bioorganic Synthesis, Leiden Institute of Chemistry, Leiden University, Leiden 2300 RA, The Netherlands
| | - Marco Allarà
- ⊥Endocannabinoid Research Group, Institute of Biomolecular Chemistry, Pozzuoli 80078, Italy
| | - Bogdan I Florea
- †Department of Bioorganic Synthesis, Leiden Institute of Chemistry, Leiden University, Leiden 2300 RA, The Netherlands
| | - Vincenzo Di Marzo
- ⊥Endocannabinoid Research Group, Institute of Biomolecular Chemistry, Pozzuoli 80078, Italy
| | - Wytse J Wadman
- ‡Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam 1000 GG, The Netherlands
| | - Chris G Kruse
- ‡Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam 1000 GG, The Netherlands
| | - Herman S Overkleeft
- †Department of Bioorganic Synthesis, Leiden Institute of Chemistry, Leiden University, Leiden 2300 RA, The Netherlands
| | - Thomas Hankemeier
- §Division of Analytical Biosciences, Leiden Academic Centre for Drug Research, Leiden University, Leiden 2300 RA, The Netherlands
| | - Taco R Werkman
- ‡Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam 1000 GG, The Netherlands
| | - Benjamin F Cravatt
- ∥Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Mario van der Stelt
- †Department of Bioorganic Synthesis, Leiden Institute of Chemistry, Leiden University, Leiden 2300 RA, The Netherlands
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22
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Kishimoto Y, Cagniard B, Yamazaki M, Nakayama J, Sakimura K, Kirino Y, Kano M. Task-specific enhancement of hippocampus-dependent learning in mice deficient in monoacylglycerol lipase, the major hydrolyzing enzyme of the endocannabinoid 2-arachidonoylglycerol. Front Behav Neurosci 2015; 9:134. [PMID: 26082696 PMCID: PMC4451424 DOI: 10.3389/fnbeh.2015.00134] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 05/11/2015] [Indexed: 12/03/2022] Open
Abstract
Growing evidence indicates that the endocannabinoid system is important for the acquisition and/or extinction of learning and memory. However, it is unclear which endocannabinoid(s) play(s) a crucial role in these cognitive functions, especially memory extinction. To elucidate the physiological role of 2-arachidonoylglycerol (2-AG), a major endocannabinoid, in behavioral and cognitive functions, we conducted a comprehensive behavioral test battery in knockout (KO) mice deficient in monoacylglycerol lipase (MGL), the major hydrolyzing enzyme of 2-AG. We found age-dependent increases in spontaneous physical activity (SPA) in MGL KO mice. Next, we tested the MGL KO mice using 5 hippocampus-dependent learning paradigms (i.e., Morris water maze (MWM), contextual fear conditioning, novel object recognition test, trace eyeblink conditioning, and water-finding test). In the MWM, MGL KO mice showed normal acquisition of reference memory, but exhibited significantly faster extinction of the learned behavior. Moreover, they showed faster memory acquisition on the reversal-learning task of the MWM. In contrast, in the contextual fear conditioning, MGL KO mice tended to show slower memory extinction. In the novel object recognition and water-finding tests, MGL KO mice exhibited enhanced memory acquisition. Trace eyeblink conditioning was not altered in MGL KO mice throughout the acquisition and extinction phases. These results indicate that 2-AG signaling is important for hippocampus-dependent learning and memory, but its contribution is highly task-dependent.
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Affiliation(s)
- Yasushi Kishimoto
- Laboratory of Neurobiophysics, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University Sanuki, Kagawa, Japan
| | - Barbara Cagniard
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo Bunkyo-ku, Tokyo, Japan
| | - Maya Yamazaki
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University Niigata, Japan
| | - Junko Nakayama
- Laboratory of Neurobiophysics, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University Sanuki, Kagawa, Japan
| | - Kenji Sakimura
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University Niigata, Japan
| | - Yutaka Kirino
- Laboratory of Neurobiophysics, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University Sanuki, Kagawa, Japan
| | - Masanobu Kano
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo Bunkyo-ku, Tokyo, Japan
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23
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Belluomo I, Matias I, Pernègre C, Marsicano G, Chaouloff F. Opposite control of frontocortical 2-arachidonoylglycerol turnover rate by cannabinoid type-1 receptors located on glutamatergic neurons and on astrocytes. J Neurochem 2015; 133:26-37. [DOI: 10.1111/jnc.13044] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 12/17/2014] [Accepted: 01/13/2015] [Indexed: 01/24/2023]
Affiliation(s)
- Ilaria Belluomo
- Plateforme de Chimie Analytique; NeuroCentre INSERM U862; Bordeaux France
| | - Isabelle Matias
- Plateforme de Chimie Analytique; NeuroCentre INSERM U862; Bordeaux France
| | - Camille Pernègre
- Equipe Endocannabinoïdes & NeuroAdaptation; NeuroCentre INSERM U862; Bordeaux France
| | - Giovanni Marsicano
- Equipe Endocannabinoïdes & NeuroAdaptation; NeuroCentre INSERM U862; Bordeaux France
| | - Francis Chaouloff
- Equipe Endocannabinoïdes & NeuroAdaptation; NeuroCentre INSERM U862; Bordeaux France
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24
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Zelasko S, Arnold WR, Das A. Endocannabinoid metabolism by cytochrome P450 monooxygenases. Prostaglandins Other Lipid Mediat 2014; 116-117:112-23. [PMID: 25461979 DOI: 10.1016/j.prostaglandins.2014.11.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 11/11/2014] [Accepted: 11/13/2014] [Indexed: 01/01/2023]
Abstract
The endogenous cannabinoid system was first uncovered following studies of the recreational drug Cannabis sativa. It is now recognized as a vital network of signaling pathways that regulate several physiological processes. Following the initial discovery of the cannabinoid receptors 1 (CB1) and 2 (CB2), activated by Cannabis-derived analogs, many endogenous fatty acids termed "endocannabinoids" are now known to be partial agonists of the CB receptors. At present, the most thoroughly studied endocannabinoid signaling molecules are anandamide (AEA) and 2-arachidonylglycerol (2-AG), which are both derived from arachidonic acid. Both AEA and 2-AG are also substrates for the eicosanoid-synthesizing pathways, namely, certain cyclooxygenase (COX), lipoxygenase (LOX), and cytochrome P450 (CYP) enzymes. In the past, research in the endocannabinoid field focused on the interaction of AEA and 2-AG with the COX and LOX enzymes, but accumulating evidence also points to the involvement of CYPs in modulating endocannabinoid signaling. The focus of this review is to explore the current understanding of CYP-mediated metabolism of endocannabinoids.
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Affiliation(s)
- Susan Zelasko
- Department of Comparative Biosciences, University of Illinois Urbana-Champaign, Urbana, IL 61802, United States
| | - William R Arnold
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL 61802, United States
| | - Aditi Das
- Department of Comparative Biosciences, University of Illinois Urbana-Champaign, Urbana, IL 61802, United States; Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL 61802, United States; Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL 61802, United States; Department of Bioengineering, University of Illinois Urbana-Champaign, Urbana, IL 61802, United States.
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KANO M. Control of synaptic function by endocannabinoid-mediated retrograde signaling. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2014; 90:235-250. [PMID: 25169670 PMCID: PMC4237895 DOI: 10.2183/pjab.90.235] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Accepted: 05/30/2014] [Indexed: 06/03/2023]
Abstract
Since the first reports in 2001, great advances have been made towards the understanding of endocannabinoid-mediated synaptic modulation. Electrophysiological studies have revealed that one of the two major endocannabinoids, 2-arachidonoylglycerol (2-AG), is produced from membrane lipids upon postsynaptic Ca(2+) elevation and/or activation of Gq/11-coupled receptors, and released from postsynaptic neurons. The released 2-AG then acts retrogradely onto presynaptic cannabinoid CB1 receptors and induces suppression of neurotransmitter release either transiently or persistently. These forms of 2-AG-mediated retrograde synaptic modulation are functional throughout the brain. The other major endocannabinoid, anandamide, mediates a certain form of endocannabinoid-mediated long-term depression (LTD). Anandamide also functions as an agonist for transient receptor potential vanilloid receptor type 1 (TRPV1) and mediates endocannabinoid-independent and TRPV1-dependent forms of LTD. It has also been demonstrated that the endocannabinoid system itself is plastic, which can be either up- or down-regulated by experimental or environmental conditions. In this review, I will make an overview of the mechanisms underlying endocannabinoid-mediated synaptic modulation.
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Affiliation(s)
- Masanobu KANO
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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26
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Anandamide, cannabinoid type 1 receptor, and NMDA receptor activation mediate non-Hebbian presynaptically expressed long-term depression at the first central synapse for visceral afferent fibers. J Neurosci 2013; 33:12627-37. [PMID: 23904599 DOI: 10.1523/jneurosci.1028-13.2013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Presynaptic long-term depression (LTD) of synapse efficacy generally requires coordinated activity between presynaptic and postsynaptic neurons and a retrograde signal synthesized by the postsynaptic cell in an activity-dependent manner. In this study, we examined LTD in the rat nucleus tractus solitarii (NTS), a brainstem nucleus that relays homeostatic information from the internal body to the brain. We found that coactivation of N-methyl-D-aspartate receptors (NMDARs) and type 1 cannabinoid receptors (CB1Rs) induces LTD at the first central excitatory synapse between visceral fibers and NTS neurons. This LTD is presynaptically expressed. However, neither postsynaptic activation of NMDARs nor postsynaptic calcium influx are required for its induction. Direct activation of NMDARs triggers cannabinoid-dependent LTD. In addition, LTD is unaffected by blocking 2-arachidonyl-glycerol synthesis, but its induction threshold is lowered by preventing fatty acid degradation. Altogether, our data suggest that LTD in NTS neurons may be entirely expressed at the presynaptic level by local anandamide synthesis.
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27
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Hashimotodani Y, Ohno-Shosaku T, Tanimura A, Kita Y, Sano Y, Shimizu T, Di Marzo V, Kano M. Acute inhibition of diacylglycerol lipase blocks endocannabinoid-mediated retrograde signalling: evidence for on-demand biosynthesis of 2-arachidonoylglycerol. J Physiol 2013; 591:4765-76. [PMID: 23858009 DOI: 10.1113/jphysiol.2013.254474] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The endocannabinoid (eCB) 2-arachidonoylglycerol (2-AG) produced by diacylglycerol lipase α (DGLα) is one of the best-characterized retrograde messengers at central synapses. It has been thought that 2-AG is produced 'on demand' upon activation of postsynaptic neurons. However, recent studies propose that 2-AG is pre-synthesized by DGLα and stored in neurons, and that 2-AG is released from such 'pre-formed pools' without the participation of DGLα. To address whether the 2-AG source for retrograde signalling is the on-demand biosynthesis by DGLα or the mobilization from pre-formed pools, we examined the effects of acute pharmacological inhibition of DGL by a novel potent DGL inhibitor, OMDM-188, on retrograde eCB signalling triggered by Ca(2+) elevation, Gq/11 protein-coupled receptor activation or synergy of these two stimuli in postsynaptic neurons. We found that pretreatment for 1 h with OMDM-188 effectively blocked depolarization-induced suppression of inhibition (DSI), a purely Ca(2+)-dependent form of eCB signalling, in slices from the hippocampus, striatum and cerebellum. We also found that at parallel fibre-Purkinje cell synapses in the cerebellum OMDM-188 abolished synaptically induced retrograde eCB signalling, which is known to be caused by the synergy of postsynaptic Ca(2+) elevation and group I metabotropic glutamate receptor (I-mGluR) activation. Moreover, brief OMDM-188 treatments for several minutes were sufficient to suppress both DSI and the I-mGluR-induced retrograde eCB signalling in cultured hippocampal neurons. These results are consistent with the hypothesis that 2-AG for synaptic retrograde signalling is supplied as a result of on-demand biosynthesis by DGLα rather than mobilization from presumptive pre-formed pools.
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Affiliation(s)
- Yuki Hashimotodani
- M. Kano: Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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28
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Straiker A, Min KT, Mackie K. Fmr1 deletion enhances and ultimately desensitizes CB(1) signaling in autaptic hippocampal neurons. Neurobiol Dis 2013; 56:1-5. [PMID: 23578490 DOI: 10.1016/j.nbd.2013.04.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Revised: 03/30/2013] [Accepted: 04/02/2013] [Indexed: 12/13/2022] Open
Abstract
Fragile X Syndrome (FXS) is a heritable form of mental retardation caused by a non-coding trinucleotide expansion of the FMR1 gene leading to loss of expression of this RNA binding protein. Mutations in this gene are strongly linked to enhanced Group I metabotropic glutamate receptor (mGluR) signaling. A recent report found that mGluR5-dependent endogenous cannabinoid signaling is enhanced in hippocampal slices from fmr1 knockout mice, suggesting a link between FXS and cannabinoid signaling. Alterations in cannabinoid signaling have an impact on learning and memory and may therefore be linked to some aspects of the FXS phenotype. We have used autaptic hippocampal neurons cultured from fmr1 knockout mice to further explore the interaction between endocannabinoid signaling and FMRP. These neurons express several robust forms of retrograde endocannabinoid signaling including depolarization induced suppression of excitation (DSE) and a metabotropic form (MSE) that results from Group I mGluR activation. We now report that young fmr1 neurons exhibit considerably enhanced DSE, likely via increased production of 2-AG, rather than enhanced mGluR-MSE. We find that depolarizations as brief as 50ms, which do not ordinarily produce DSE, routinely inhibited glutamate release. Furthermore, as neuronal cultures mature, CB1-receptor signaling strongly desensitizes. Our results suggest that loss of FMRP broadly affects the endocannabinoid signaling system, possibly through local 2-AG over production. Furthermore, the net effect of the loss of FMRP may actually be diminished cannabinoid signaling due to receptor desensitization as an adaptation to 2-AG overproduction.
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Affiliation(s)
- Alex Straiker
- Department of Psychological & Brain Sciences, Gill Center for Biomedical Sciences, Indiana University, Bloomington, IN 47405, USA.
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29
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Rani Sagar D, Burston JJ, Woodhams SG, Chapman V. Dynamic changes to the endocannabinoid system in models of chronic pain. Philos Trans R Soc Lond B Biol Sci 2013; 367:3300-11. [PMID: 23108548 DOI: 10.1098/rstb.2011.0390] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The analgesic effects of cannabinoid ligands, mediated by CB1 receptors are well established. However, the side-effect profile of CB1 receptor ligands has necessitated the search for alternative cannabinoid-based approaches to analgesia. Herein, we review the current literature describing the impact of chronic pain states on the key components of the endocannabinoid receptor system, in terms of regionally restricted changes in receptor expression and levels of key metabolic enzymes that influence the local levels of the endocannabinoids. The evidence that spinal CB2 receptors have a novel role in the modulation of nociceptive processing in models of neuropathic pain, as well as in models of cancer pain and arthritis is discussed. Recent advances in our understanding of the spinal location of the key enzymes that regulate the levels of the endocannabinoid 2-AG are discussed alongside the outcomes of recent studies of the effects of inhibiting the catabolism of 2-AG in models of pain. The complexities of the enzymes capable of metabolizing both anandamide (AEA) and 2-AG have become increasingly apparent. More recently, it has come to light that some of the metabolites of AEA and 2-AG generated by cyclooxygenase-2, lipoxygenases and cytochrome P450 are biologically active and can either exacerbate or inhibit nociceptive signalling.
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Affiliation(s)
- Devi Rani Sagar
- Arthritis Research UK Pain Centre, University of Nottingham, School of Biomedical Sciences, Queen's Medical Centre, Nottingham NG7 2UH, UK
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30
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Sugawara Y, Echigo R, Kashima K, Minami H, Watanabe M, Nishikawa Y, Muranishi M, Yoneda M, Ohno-Shosaku T. Intracellular calcium level is an important factor influencing ion channel modulations by PLC-coupled metabotropic receptors in hippocampal neurons. Brain Res 2013; 1512:9-21. [PMID: 23548601 DOI: 10.1016/j.brainres.2013.03.040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 03/18/2013] [Accepted: 03/19/2013] [Indexed: 10/27/2022]
Abstract
Signaling pathways involving phospholipase C (PLC) are involved in various neural functions. Understanding how these pathways are regulated will lead to a better understanding of their roles in neural functions. Previous studies demonstrated that receptor-driven PLCβ activation depends on intracellular Ca(2+) concentration ([Ca(2+)]i), suggesting the possibility that PLCβ-dependent cellular responses are basically Ca(2+) dependent. To test this possibility, we examined whether modulations of ion channels driven by PLC-coupled metabotropic receptors are sensitive to [Ca(2+)]i using cultured hippocampal neurons. Muscarinic activation triggered an inward current at -100 mV (the equilibrium potential for K(+)) in a subpopulation of neurons. This current response was suppressed by pirenzepine (an M1-preferring antagonist), PLC inhibitor, non-selective cation channel blocker, and lowering [Ca(2+)]i. Using the neurons showing no response at -100 mV, effects of muscarinic activation on K(+) channels were examined at -40 mV. Muscarinic activation induced a transient decrease of the holding outward current. This current response was mimicked and occluded by XE991, an M-current K(+) channel blocker, suppressed by pirenzepine, PLC inhibitor and lowering [Ca(2+)]i, and enhanced by elevating [Ca(2+)]i. Similar results were obtained when group I metabotropic glutamate receptors were activated instead of muscarinic receptors. These results clearly show that ion channel modulations driven by PLC-coupled metabotropic receptors are dependent on [Ca(2+)]i, supporting the hypothesis that cellular responses induced by receptor-driven PLCβ activation are basically Ca(2+) dependent.
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Affiliation(s)
- Yuto Sugawara
- Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa 920-0942, Japan
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31
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Zachariou M, Alexander SPH, Coombes S, Christodoulou C. A biophysical model of endocannabinoid-mediated short term depression in hippocampal inhibition. PLoS One 2013; 8:e58926. [PMID: 23527052 PMCID: PMC3601106 DOI: 10.1371/journal.pone.0058926] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 02/08/2013] [Indexed: 12/22/2022] Open
Abstract
Memories are believed to be represented in the synaptic pathways of vastly interconnected networks of neurons. The plasticity of synapses, that is, their strengthening and weakening depending on neuronal activity, is believed to be the basis of learning and establishing memories. An increasing number of studies indicate that endocannabinoids have a widespread action on brain function through modulation of synap–tic transmission and plasticity. Recent experimental studies have characterised the role of endocannabinoids in mediating both short- and long-term synaptic plasticity in various brain regions including the hippocampus, a brain region strongly associated with cognitive functions, such as learning and memory. Here, we present a biophysically plausible model of cannabinoid retrograde signalling at the synaptic level and investigate how this signalling mediates depolarisation induced suppression of inhibition (DSI), a prominent form of short-term synaptic depression in inhibitory transmission in hippocampus. The model successfully captures many of the key characteristics of DSI in the hippocampus, as observed experimentally, with a minimal yet sufficient mathematical description of the major signalling molecules and cascades involved. More specifically, this model serves as a framework to test hypotheses on the factors determining the variability of DSI and investigate under which conditions it can be evoked. The model reveals the frequency and duration bands in which the post-synaptic cell can be sufficiently stimulated to elicit DSI. Moreover, the model provides key insights on how the state of the inhibitory cell modulates DSI according to its firing rate and relative timing to the post-synaptic activation. Thus, it provides concrete suggestions to further investigate experimentally how DSI modulates and is modulated by neuronal activity in the brain. Importantly, this model serves as a stepping stone for future deciphering of the role of endocannabinoids in synaptic transmission as a feedback mechanism both at synaptic and network level.
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32
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Reisenberg M, Singh PK, Williams G, Doherty P. The diacylglycerol lipases: structure, regulation and roles in and beyond endocannabinoid signalling. Philos Trans R Soc Lond B Biol Sci 2012; 367:3264-75. [PMID: 23108545 PMCID: PMC3481529 DOI: 10.1098/rstb.2011.0387] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The diacylglycerol lipases (DAGLs) hydrolyse diacylglycerol to generate 2-arachidonoylglycerol (2-AG), the most abundant ligand for the CB(1) and CB(2) cannabinoid receptors in the body. DAGL-dependent endocannabinoid signalling regulates axonal growth and guidance during development, and is required for the generation and migration of new neurons in the adult brain. At developed synapses, 2-AG released from postsynaptic terminals acts back on presynaptic CB(1) receptors to inhibit the secretion of both excitatory and inhibitory neurotransmitters, with this DAGL-dependent synaptic plasticity operating throughout the nervous system. Importantly, the DAGLs have functions that do not involve cannabinoid receptors. For example, 2-AG is the precursor of arachidonic acid in a pathway that maintains the level of this essential lipid in the brain and other organs. This pathway also drives the cyclooxygenase-dependent generation of inflammatory prostaglandins in the brain, which has recently been implicated in the degeneration of dopaminergic neurons in Parkinson's disease. Remarkably, we still know very little about the mechanisms that regulate DAGL activity-however, key insights can be gleaned by homology modelling against other α/β hydrolases and from a detailed examination of published proteomic studies and other databases. These identify a regulatory loop with a highly conserved signature motif, as well as phosphorylation and palmitoylation as post-translational mechanisms likely to regulate function.
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Affiliation(s)
| | | | - Gareth Williams
- Wolfson Centre for Age-Related Diseases, King's College London, SE1 9RT, UK
| | - Patrick Doherty
- Wolfson Centre for Age-Related Diseases, King's College London, SE1 9RT, UK
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33
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Estradiol acutely suppresses inhibition in the hippocampus through a sex-specific endocannabinoid and mGluR-dependent mechanism. Neuron 2012; 74:801-8. [PMID: 22681685 DOI: 10.1016/j.neuron.2012.03.035] [Citation(s) in RCA: 219] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/19/2012] [Indexed: 11/21/2022]
Abstract
The steroid 17β-estradiol (E2) is well known to influence hippocampal functions such as memory, affective behaviors, and epilepsy. There is growing awareness that in addition to responding to ovarian E2, the hippocampus of both males and females synthesizes E2 as a neurosteroid that could acutely modulate synaptic function. Previous work on acute E2 actions in the hippocampus has focused on excitatory synapses. Here, we show that E2 rapidly suppresses inhibitory synaptic transmission in hippocampal CA1. E2 acts through the α form of the estrogen receptor to stimulate postsynaptic mGluR1-dependent mobilization of the endocannabinoid anandamide, which retrogradely suppresses GABA release from CB1 receptor-containing inhibitory presynaptic boutons. Remarkably, this effect of E2 is sex specific, occurring in females but not in males. Acute E2 modulation of endocannabinoid tone and consequent suppression of inhibition provide a mechanism by which neurosteroid E2 could modulate hippocampus-dependent behaviors in a sex-specific manner.
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34
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Gregg LC, Jung KM, Spradley JM, Nyilas R, Suplita RL, Zimmer A, Watanabe M, Mackie K, Katona I, Piomelli D, Hohmann AG. Activation of type 5 metabotropic glutamate receptors and diacylglycerol lipase-α initiates 2-arachidonoylglycerol formation and endocannabinoid-mediated analgesia. J Neurosci 2012; 32:9457-68. [PMID: 22787031 PMCID: PMC3652685 DOI: 10.1523/jneurosci.0013-12.2012] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2011] [Revised: 05/11/2012] [Accepted: 05/17/2012] [Indexed: 11/21/2022] Open
Abstract
Acute stress reduces pain sensitivity by engaging an endocannabinoid signaling circuit in the midbrain. The neural mechanisms governing this process and molecular identity of the endocannabinoid substance(s) involved are unknown. We combined behavior, pharmacology, immunohistochemistry, RNA interference, quantitative RT-PCR, enzyme assays, and lipidomic analyses of endocannabinoid content to uncover the role of the endocannabinoid 2-arachidonoyl-sn-glycerol (2-AG) in controlling pain sensitivity in vivo. Here, we show that footshock stress produces antinociception in rats by activating type 5 metabotropic glutamate receptors (mGlu(5)) in the dorsolateral periaqueductal gray (dlPAG) and mobilizing 2-AG. Stimulation of mGlu(5) in the dlPAG with DHPG [(S)-3,5-dihydroxyphenylglycine] triggered 2-AG formation and enhanced stress-dependent antinociception through a mechanism dependent upon both postsynaptic diacylglycerol lipase (DGL) activity, which releases 2-AG, and presynaptic CB(1) cannabinoid receptors. Pharmacological blockade of DGL activity in the dlPAG with RHC80267 [1,6-bis(cyclohexyloximinocarbonylamino)hexane] and (-)-tetrahydrolipstatin (THL), which inhibit activity of DGL-α and DGL-β isoforms, suppressed stress-induced antinociception. Inhibition of DGL activity in the dlPAG with THL selectively decreased accumulation of 2-AG without altering levels of anandamide. The putative 2-AG-synthesizing enzyme DGL-α colocalized with mGlu(5) at postsynaptic sites of the dlPAG, whereas CB(1) was confined to presynaptic terminals, consistent with a role for 2-AG as a retrograde signaling messenger. Finally, virally mediated silencing of DGL-α, but not DGL-β, transcription in the dlPAG mimicked effects of DGL inhibition in suppressing both endocannabinoid-mediated stress antinociception and 2-AG formation. The results indicate that activation of the postsynaptic mGlu(5)-DGL-α cascade triggers retrograde 2-AG signaling in vivo. This pathway is required for endocannabinoid-mediated stress-induced analgesia.
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Affiliation(s)
- Laura C. Gregg
- Neuroscience Program, Biomedical and Health Sciences Institute, and
| | - Kwang-Mook Jung
- Department of Pharmacology, University of California, Irvine, Irvine, California 92697
| | | | - Rita Nyilas
- Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1083 Budapest, Hungary
| | - Richard L. Suplita
- Psychology Department, University of Georgia, Athens, Georgia 30602-3013
| | - Andreas Zimmer
- Insitute of Molecular Psychiatry, University of Bonn, 53105 Bonn, Germany
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University School of Medicine, Sapporo 060-8638, Japan
| | - Ken Mackie
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana 47405-2204, and
| | - István Katona
- Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1083 Budapest, Hungary
| | - Daniele Piomelli
- Department of Pharmacology, University of California, Irvine, Irvine, California 92697
- Unit of Drug Discovery and Development, Italian Institute of Technology, 16163 Genoa, Italy
| | - Andrea G. Hohmann
- Neuroscience Program, Biomedical and Health Sciences Institute, and
- Psychology Department, University of Georgia, Athens, Georgia 30602-3013
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana 47405-2204, and
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35
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Synapse type-independent degradation of the endocannabinoid 2-arachidonoylglycerol after retrograde synaptic suppression. Proc Natl Acad Sci U S A 2012; 109:12195-200. [PMID: 22783023 DOI: 10.1073/pnas.1204404109] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The endocannabinoid 2-arachidonoylglycerol (2-AG) mediates retrograde synaptic suppression. Although the mechanisms of 2-AG production are well characterized, how 2-AG is degraded is less clearly understood. Here we found that expression of the 2-AG hydrolyzing enzyme monoacylglycerol lipase (MGL) was highly heterogeneous in the cerebellum, being rich within parallel fiber (PF) terminals, weak in Bergman glia (BG), and absent in other synaptic terminals. Despite this highly selective MGL expression pattern, 2-AG-mediated retrograde suppression was significantly prolonged at not only PF-Purkinje cell (PC) synapses but also climbing fiber-PC synapses in granule cell-specific MGL knockout (MGL-KO) mice whose cerebellar MGL expression was confined to the BG. Virus-mediated expression of MGL into the BG of global MGL-KO mice significantly shortened 2-AG-mediated retrograde suppression at PF-PC synapses. Furthermore, contribution of MGL to termination of 2-AG signaling depended on the distance from MGL-rich PFs to inhibitory synaptic terminals. Thus, 2-AG is degraded in a synapse-type independent manner by MGL present in PFs and the BG. The results of the present study strongly suggest that MGL regulates 2-AG signaling rather broadly within a certain range of neural tissue, although MGL expression is heterogeneous and limited to a subset of nerve terminals and astrocytes.
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36
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Gating the polarity of endocannabinoid-mediated synaptic plasticity by nitric oxide in the spinal locomotor network. J Neurosci 2012; 32:5097-105. [PMID: 22496555 DOI: 10.1523/jneurosci.5850-11.2012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The final motor output underlying behavior arises from an appropriate balance between excitation and inhibition within neural networks. Retrograde signaling by endocannabinoids adapts synaptic strengths and the global activity of neural networks. In the spinal cord, endocannabinoids are mobilized postsynaptically from network neurons and act retrogradely on presynaptic cannabinoid receptors to potentiate the locomotor frequency. However, it is still unclear whether mechanisms exist within the locomotor networks that determine the sign of the modulation by cannabinoid receptors to differentially regulate excitation and inhibition. In this study, using the lamprey spinal cord in vitro, we first report that 2-AG (2-arachidonyl glycerol) is mobilized by network neurons and underlies a form of modulation that is embedded within the locomotor networks. We then show that the polarity of the endocannabinoid modulation is gated by nitric oxide to enable simultaneously potentiation of excitation and depression of inhibition within the spinal locomotor networks. Our results suggest that endocannabinoid and nitric oxide systems interact to mediate inversion of the polarity of synaptic plasticity within the locomotor networks. Thus, endocannabinoid and nitric oxide shift in the excitation-inhibition balance to set the excitability of the spinal locomotor network.
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37
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Johnston M, Bhatt SR, Sikka S, Mercier RW, West JM, Makriyannis A, Gatley SJ, Duclos RI. Assay and inhibition of diacylglycerol lipase activity. Bioorg Med Chem Lett 2012; 22:4585-92. [PMID: 22738638 DOI: 10.1016/j.bmcl.2012.05.101] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 05/25/2012] [Accepted: 05/29/2012] [Indexed: 11/25/2022]
Abstract
A series of N-formyl-α-amino acid esters of β-lactone derivatives structurally related to tetrahydrolipstatin (THL) and O-3841 were synthesized that inhibit human and murine diacylglycerol lipase (DAGL) activities. New ether lipid reporter compounds were developed for an in vitro assay to efficiently screen inhibitors of 1,2-diacyl-sn-glycerol hydrolysis and related lipase activities using fluorescence resonance energy transfer (FRET). A standardized thin layer chromatography (TLC) radioassay of diacylglycerol lipase activity utilizing the labeled endogenous substrate [1″-(14)C]1-stearoyl-2-arachidonoyl-sn-glycerol with phosphorimaging detection was used to quantify inhibition by following formation of the initial product [1″-(14)C]2-arachidonoylglycerol and further hydrolysis under the assay conditions to [1-(14)C]arachidonic acid.
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Affiliation(s)
- Meghan Johnston
- Center for Drug Discovery, Northeastern University, 360 Huntington Avenue, Boston, MA 02115, USA.
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38
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Atwood BK, Straiker A, Mackie K. CB₂ cannabinoid receptors inhibit synaptic transmission when expressed in cultured autaptic neurons. Neuropharmacology 2012; 63:514-23. [PMID: 22579668 DOI: 10.1016/j.neuropharm.2012.04.024] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 04/18/2012] [Accepted: 04/23/2012] [Indexed: 11/18/2022]
Abstract
The role of CB₂ in the central nervous system, particularly in neurons, has generated much controversy. Fueling the controversy are imperfect tools, which have made conclusive identification of CB₂ expressing neurons problematic. Imprecise localization of CB₂ has made it difficult to determine its function in neurons. Here we avoid the localization controversy and directly address the question if CB₂ can modulate neurotransmission. CB₂ was expressed in excitatory hippocampal autaptic neurons obtained from CB₁ null mice. Whole-cell patch clamp recordings were made from these neurons to determine the effects of CB₂ on short-term synaptic plasticity. CB₂ expression restored depolarization induced suppression of excitation to these neurons, which was lost following genetic ablation of CB₁. The endocannabinoid 2-arachidonylglycerol (2-AG) mimicked the effects of depolarization in CB₂ expressing neurons. Interestingly, ongoing basal production of 2-AG resulted in constitutive activation of CB₂, causing a tonic inhibition of neurotransmission that was relieved by the CB₂ antagonist AM630 or the diacylglycerol lipase inhibitor RHC80267. Through immunocytochemistry and analysis of spontaneous EPSCs, paired pulse ratios and coefficients of variation we determined that CB₂ exerts its function at a presynaptic site of action, likely through inhibition of voltage gated calcium channels. Therefore CB₂ expressed in neurons effectively mimics the actions of CB₁. Thus neuronal CB₂ is well suited to integrate into conventional neuronal endocannabinoid signaling processes, with its specific role determined by its unique and highly inducible expression profile.
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MESH Headings
- Animals
- Animals, Newborn
- Arachidonic Acids/antagonists & inhibitors
- Arachidonic Acids/metabolism
- Arachidonic Acids/pharmacology
- Astrocytes/cytology
- Cells, Cultured
- Endocannabinoids/antagonists & inhibitors
- Endocannabinoids/metabolism
- Endocannabinoids/pharmacology
- Enzyme Inhibitors/pharmacology
- Glycerides/antagonists & inhibitors
- Glycerides/metabolism
- Glycerides/pharmacology
- Heterozygote
- Hippocampus/cytology
- Hippocampus/drug effects
- Hippocampus/metabolism
- Lipoprotein Lipase/antagonists & inhibitors
- Mice
- Mice, Knockout
- Nerve Tissue Proteins/agonists
- Nerve Tissue Proteins/antagonists & inhibitors
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Neurons/cytology
- Neurons/drug effects
- Neurons/metabolism
- Patch-Clamp Techniques
- Presynaptic Terminals/drug effects
- Presynaptic Terminals/metabolism
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB2/agonists
- Receptor, Cannabinoid, CB2/antagonists & inhibitors
- Receptor, Cannabinoid, CB2/genetics
- Receptor, Cannabinoid, CB2/metabolism
- Recombinant Fusion Proteins/metabolism
- Synaptic Transmission/drug effects
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Affiliation(s)
- Brady K Atwood
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana University, 1101 E. 10th Street, Bloomington, IN 47405, USA.
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Glucocorticoids interact with the hippocampal endocannabinoid system in impairing retrieval of contextual fear memory. Proc Natl Acad Sci U S A 2012; 109:3504-9. [PMID: 22331883 DOI: 10.1073/pnas.1200742109] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
There is extensive evidence that glucocorticoid hormones impair the retrieval of memory of emotionally arousing experiences. Although it is known that glucocorticoid effects on memory retrieval impairment depend on rapid interactions with arousal-induced noradrenergic activity, the exact mechanism underlying this presumably nongenomically mediated glucocorticoid action remains to be elucidated. Here, we show that the hippocampal endocannabinoid system, a rapidly activated retrograde messenger system, is involved in mediating glucocorticoid effects on retrieval of contextual fear memory. Systemic administration of corticosterone (0.3-3 mg/kg) to male Sprague-Dawley rats 1 h before retention testing impaired the retrieval of contextual fear memory without impairing the retrieval of auditory fear memory or directly affecting the expression of freezing behavior. Importantly, a blockade of hippocampal CB1 receptors with AM251 prevented the impairing effect of corticosterone on retrieval of contextual fear memory, whereas the same impairing dose of corticosterone increased hippocampal levels of the endocannabinoid 2-arachidonoylglycerol. We also found that antagonism of hippocampal β-adrenoceptor activity with local infusions of propranolol blocked the memory retrieval impairment induced by the CB receptor agonist WIN55,212-2. Thus, these findings strongly suggest that the endocannabinoid system plays an intermediary role in regulating rapid glucocorticoid effects on noradrenergic activity in impairing memory retrieval of emotionally arousing experiences.
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The biology that underpins the therapeutic potential of cannabis-based medicines for the control of spasticity in multiple sclerosis. Mult Scler Relat Disord 2012; 1:64-75. [PMID: 25876933 DOI: 10.1016/j.msard.2011.11.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Accepted: 11/17/2011] [Indexed: 12/14/2022]
Abstract
Cannabis-based medicines have recently been approved for the treatment of pain and spasticity in multiple sclerosis (MS). This supports the original perceptions of people with MS, who were using illegal street cannabis for symptom control and pre-clinical testing in animal models of MS. This activity is supported both by the biology of the disease and the biology of the cannabis plant and the endocannabinoid system. MS results from disease that impairs neurotransmission and this is controlled by cannabinoid receptors and endogenous cannabinoid ligands. This can limit spasticity and may also influence the processes that drive the accumulation of progressive disability.
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Howlett AC, Reggio PH, Childers SR, Hampson RE, Ulloa NM, Deutsch DG. Endocannabinoid tone versus constitutive activity of cannabinoid receptors. Br J Pharmacol 2012; 163:1329-43. [PMID: 21545414 DOI: 10.1111/j.1476-5381.2011.01364.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
This review evaluates the cellular mechanisms of constitutive activity of the cannabinoid (CB) receptors, its reversal by inverse agonists, and discusses the pitfalls and problems in the interpretation of the research data. The notion is presented that endogenously produced anandamide (AEA) and 2-arachidonoylglycerol (2-AG) serve as autocrine or paracrine stimulators of the CB receptors, giving the appearance of constitutive activity. It is proposed that one cannot interpret inverse agonist studies without inference to the receptors' environment vis-à-vis the endocannabinoid agonists which themselves are highly lipophilic compounds with a preference for membranes. The endocannabinoid tone is governed by a combination of synthetic pathways and inactivation involving transport and degradation. The synthesis and degradation of 2-AG is well characterized, and 2-AG has been strongly implicated in retrograde signalling in neurons. Data implicating endocannabinoids in paracrine regulation have been described. Endocannabinoid ligands can traverse the cell's interior and potentially be stored on fatty acid-binding proteins (FABPs). Molecular modelling predicts that the endocannabinoids derived from membrane phospholipids can laterally diffuse to enter the CB receptor from the lipid bilayer. Considering that endocannabinoid signalling to CB receptors is a much more likely scenario than is receptor activation in the absence of agonist ligands, researchers are advised to refrain from assuming constitutive activity except for experimental models known to be devoid of endocannabinoid ligands.
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Affiliation(s)
- Allyn C Howlett
- Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Winston-Salem, NC 27157, USA.
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42
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Wang M, Hill MN, Zhang L, Gorzalka BB, Hillard CJ, Alger BE. Acute restraint stress enhances hippocampal endocannabinoid function via glucocorticoid receptor activation. J Psychopharmacol 2012; 26:56-70. [PMID: 21890595 PMCID: PMC3373303 DOI: 10.1177/0269881111409606] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Exposure to behavioural stress normally triggers a complex, multilevel response of the hypothalamic-pituitary-adrenal (HPA) axis that helps maintain homeostatic balance. Although the endocannabinoid (eCB) system (ECS) is sensitive to chronic stress, few studies have directly addressed its response to acute stress. Here we show that acute restraint stress enhances eCB-dependent modulation of GABA release measured by whole-cell voltage clamp of inhibitory postsynaptic currents (IPSCs) in rat hippocampal CA1 pyramidal cells in vitro. Both Ca(2+)-dependent, eCB-mediated depolarization-induced suppression of inhibition (DSI), and muscarinic cholinergic receptor (mAChR)-mediated eCB mobilization are enhanced following acute stress exposure. DSI enhancement is dependent on the activation of glucocorticoid receptors (GRs) and is mimicked by both in vivo and in vitro corticosterone treatment. This effect does not appear to involve cyclooxygenase-2 (COX-2), an enzyme that can degrade eCBs; however, treatment of hippocampal slices with the L-type calcium (Ca(2+)) channel inhibitor, nifedipine, reverses while an agonist of these channels mimics the effect of in vivo stress. Finally, we find that acute stress produces a delayed (by 30 min) increase in the hippocampal content of 2-arachidonoylglycerol, the eCB responsible for DSI. These results support the hypothesis that the ECS is a biochemical effector of glucocorticoids in the brain, linking stress with changes in synaptic strength.
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Affiliation(s)
- Meina Wang
- Department of Physiology, Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA 21201
| | - Matthew N. Hill
- Department of Psychology, University of British Columbia, Vancouver, BC Canada
| | - Longhua Zhang
- Department of Physiology, Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA 21201
| | - Boris B. Gorzalka
- Department of Psychology, University of British Columbia, Vancouver, BC Canada
| | - Cecilia J. Hillard
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, USA 53226
| | - Bradley E. Alger
- Department of Physiology, Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA 21201
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Activation of orexin 1 receptors in the periaqueductal gray of male rats leads to antinociception via retrograde endocannabinoid (2-arachidonoylglycerol)-induced disinhibition. J Neurosci 2011; 31:14600-10. [PMID: 21994376 DOI: 10.1523/jneurosci.2671-11.2011] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Orexin A and B are hypothalamic peptides known to modulate arousal, feeding, and reward via OX1 and OX2 receptors. Orexins are also antinociceptive in the brain, but their mechanism(s) of action remain unclear. Here, we investigated the antinociceptive mechanism of orexin A in the rat ventrolateral periaqueductal gray (vlPAG), a midbrain region crucial for initiating descending pain inhibition. In vlPAG slices, orexin A (30-300 nm) depressed GABAergic evoked IPSCs. This effect was blocked by an OX1 [1-(2-methylbenzoxazol-6-yl)-3-[1,5]naphthyridin-4-yl urea (SB 334867)], but not OX2 [N-acyl 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline hydrochloride (compound 29)], antagonist. Orexin A increased the paired-pulse ratio of paired IPSCs and decreased the frequency, but not amplitude, of miniature IPSCs. Orexin A-induced IPSC depression was mimicked by (R)-(+)-[2,3-dihydro-5-methyl-3-(4-morpholinylmethyl)pyrrolo[1,2,3-de]-1,4-benzoxazin-6-yl]-1-napthalenylmethanone (WIN 55,212-2), a cannabinoid 1 (CB1) receptor agonist. 1-(2,4-Dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-(1-piperidyl)pyrazole-3-carboxamide (AM 251), a CB1 antagonist, reversed depressant effects by both agonists. Orexin A-induced IPSC depression was prevented by 1-[6-[[(17β)-3-methoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl]-1H-pyrrole-2,5-dione (U73122) and tetrahydrolipstatin, inhibitors of phospholipase C (PLC) and diacylglycerol lipase (DAGL), respectively, and enhanced by cyclohexyl[1,1'-biphenyl]-3-ylcarbamate (URB602), which inhibits enzymatic degradation of 2-arachidonoylglycerol (2-AG). Moderate DAGLα, but not DAGLβ, immunoreactivity was observed in the vlPAG. Orexin A produced an overall excitatory effect on evoked postsynaptic potentials and hence increased vlPAG neuronal activity. Intra-vlPAG microinjection of orexin A reduced hot-plate nociceptive responses in rats in a manner blocked by SB 334867 and AM 251. Therefore, orexin A may produce antinociception by activating postsynaptic OX1 receptors, stimulating synthesis of 2-AG, an endocannabinoid, through a Gq-protein-mediated PLC-DAGLα enzymatic cascade culminating in retrograde inhibition of GABA release (disinhibition) in the vlPAG.
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Yoshino H, Miyamae T, Hansen G, Zambrowicz B, Flynn M, Pedicord D, Blat Y, Westphal RS, Zaczek R, Lewis DA, Gonzalez-Burgos G. Postsynaptic diacylglycerol lipase mediates retrograde endocannabinoid suppression of inhibition in mouse prefrontal cortex. J Physiol 2011; 589:4857-84. [PMID: 21807615 DOI: 10.1113/jphysiol.2011.212225] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Depolarization-induced suppression of inhibition (DSI) is a prevailing form of endocannabinoid signalling. However, several discrepancies have arisen regarding the roles played by the two major brain endocannabinoids, 2-arachidonoylglycerol (2-AG) and anandamide, in mediating DSI. Here we studied endocannabinoid signalling in the prefrontal cortex (PFC), where several components of the endocannabinoid system have been identified, but endocannabinoid signalling remains largely unexplored. In voltage clamp recordings from mouse PFC pyramidal neurons, depolarizing steps significantly suppressed IPSCs induced by application of the cholinergic agonist carbachol. DSI in PFC neurons was abolished by extra- or intracellular application of tetrahydrolipstatin (THL), an inhibitor of the 2-AG synthesis enzyme diacylglycerol lipase (DAGL). Moreover, DSI was enhanced by inhibiting 2-AG degradation, but was unaffected by inhibiting anandamide degradation. THL, however, may affect other enzymes of lipid metabolism and does not selectively target the α (DAGLα) or β (DAGLβ) isoforms of DAGL. Therefore, we studied DSI in the PFC of DAGLα(-/-) and DAGLβ(-/-) mice generated via insertional mutagenesis by gene-trapping with retroviral vectors. Gene trapping strongly reduced DAGLα or DAGLβ mRNA levels in a locus-specific manner. In DAGLα(-/-) mice cortical levels of 2-AG were significantly decreased and DSI was completely abolished, whereas DAGLβ deficiency did not alter cortical 2-AG levels or DSI. Importantly, cortical levels of anandamide were not significantly affected in DAGLα(-/-) or DAGLβ(-/-) mice. The chronic decrease of 2-AG levels in DAGLα(-/-) mice did not globally alter inhibitory transmission or the response of cannabinoid-sensitive synapses to cannabinoid receptor stimulation, although it altered some intrinsic membrane properties. Finally, we found that repetitive action potential firing of PFC pyramidal neurons suppressed synaptic inhibition in a DAGLα-dependent manner. These results show that DSI is a prominent form of endocannabinoid signalling in PFC circuits. Moreover, the close agreement between our pharmacological and genetic studies indicates that 2-AG synthesized by postsynaptic DAGLα mediates DSI in PFC neurons.
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Affiliation(s)
- Hiroki Yoshino
- Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15261, USA
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45
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Pedicord DL, Flynn MJ, Fanslau C, Miranda M, Hunihan L, Robertson BJ, Pearce BC, Yu XC, Westphal RS, Blat Y. Molecular characterization and identification of surrogate substrates for diacylglycerol lipase α. Biochem Biophys Res Commun 2011; 411:809-14. [PMID: 21787747 DOI: 10.1016/j.bbrc.2011.07.037] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 07/12/2011] [Indexed: 12/12/2022]
Abstract
Diacylglycerol lipase α is the key enzyme in the formation of the most prevalent endocannabinoid, 2-arachidonoylglycerol in the brain. In this study we identified the catalytic triad of diacylglycerol lipase α, consisting of serine 472, aspartate 524 and histidine 650. A truncated version of diacylglycerol lipase α, spanning residues 1-687 retains complete catalytic activity suggesting that the C-terminal domain is not required for catalysis. We also report the discovery and the characterization of fluorogenic and chromogenic substrates for diacylglycerol lipase α. Assays performed with these substrates demonstrate equipotent inhibition of diacylglycerol lipase α by tetrahydrolipastatin and RHC-20867 as compared to reactions performed with the native diacylglycerol substrate. Thus, confirming the utility of assays using these substrates for identification and kinetic characterization of inhibitors from pharmaceutical collections.
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Affiliation(s)
- Donna L Pedicord
- Department of Mechanistic Biochemistry, Bristol-Myers Squibb Company, Princeton, NJ 08543, USA
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46
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Neuronal protease-activated receptor 1 drives synaptic retrograde signaling mediated by the endocannabinoid 2-arachidonoylglycerol. J Neurosci 2011; 31:3104-9. [PMID: 21414931 DOI: 10.1523/jneurosci.6000-10.2011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Protease-activated receptor 1 (PAR1) is a member of the G-protein coupled receptors that are proteolytically activated by serine proteases. Recent studies suggest a definite contribution of PAR1 to brain functions, including learning and memory. However, cellular mechanisms by which PAR1 activation influences neuronal activity are not well understood. Here we show that PAR1 activation drives retrograde endocannabinoid signaling and thereby regulates synaptic transmission. In cultured hippocampal neurons from rat, PAR1 activation by thrombin or PAR1-specific peptide agonists transiently suppressed inhibitory transmission at cannabinoid-sensitive, but not cannabinoid-insensitive, synapses. The PAR1-induced suppression of synaptic transmission was accompanied by an increase in paired-pulse ratio, and was blocked by a cannabinoid CB(1) receptor antagonist. The PAR1-induced suppression was blocked by pharmacological inhibition of postsynaptic diacylglycerol lipase (DGL), a key enzyme for biosynthesis of the major endocannabinoid 2-arachidonoylglycerol (2-AG), and was absent in knock-out mice lacking the α isoform of DGL. The PAR1-induced IPSC suppression remained intact under the blockade of metabotropic glutamate receptors and was largely resistant to the treatment that blocked Ca(2+) elevation in glial cells following PAR1 activation, which excludes the major contribution of glial PAR1 in IPSC suppression. We conclude that activation of neuronal PAR1 triggers retrograde signaling mediated by 2-AG, which activates presynaptic CB(1) receptors and suppresses transmitter release at hippocampal inhibitory synapses.
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47
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Ohno-Shosaku T, Tanimura A, Hashimotodani Y, Kano M. Endocannabinoids and Retrograde Modulation of Synaptic Transmission. Neuroscientist 2011; 18:119-32. [DOI: 10.1177/1073858410397377] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Since the first reports of endocannabinoid-mediated retrograde signaling in 2001, great advances have been made toward understanding the molecular basis and functions of the endocannabinoid system. Electrophysiological studies have revealed that the endocannabinoid system is functional at various types of synapses throughout the brain. Basic mechanisms have been clarified as to how endocannabinoids are produced and released from postsynaptic neurons and regulate neurotransmitter release through activating presynaptic cannabinoid CB1 receptors, although there remain unsolved questions and some discrepancies. In addition to this major function, recent studies suggest diverse functions of endocannabinoids, including control of other endocannabinoid-independent forms of synaptic plasticity, regulation of neuronal excitability, stimulation of glia-neuron interaction, and induction of CB1R-independent plasticity. Using recently developed pharmacological and genetic tools, behavioral studies have elucidated the roles of the endocannabinoid system in various aspects of neural functions. In this review, we make a brief overview of molecular mechanisms underlying the endocannabinoid-mediated synaptic modulation and also summarize recent findings, which shed new light on a diversity of functional roles of endocannabinoids.
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Affiliation(s)
- Takako Ohno-Shosaku
- Division of Health Science, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan
| | - Asami Tanimura
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yuki Hashimotodani
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Masanobu Kano
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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Di Marzo V. Endocannabinoid signaling in the brain: biosynthetic mechanisms in the limelight. Nat Neurosci 2011; 14:9-15. [PMID: 21187849 DOI: 10.1038/nn.2720] [Citation(s) in RCA: 134] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Studies of the endocannabinoid system in the CNS have been mostly focused on endocannabinoid receptors and inactivating mechanisms. Until recently, very little was known about the role of biosynthetic enzymes in endocannabinoid signaling. New data from the recent development of pharmacological and genetic tools for the study of these enzymes point to their fundamental role in determining where and when endocannabinoids function, and raise the possibility of new intriguing and previously unsuspected concepts in the general strategy of endocannabinoid signaling. However, even with these new tools, the cross-talk between anandamide and 2-arachidonoylglycerol biosynthesis makes it difficult to dissect one from the other, and data will need to be interpreted with this in mind.
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Affiliation(s)
- Vincenzo Di Marzo
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, CNR, Pozzuoli, Italy.
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Hampson RE, Miller F, Palchik G, Deadwyler SA. Cannabinoid receptor activation modifies NMDA receptor mediated release of intracellular calcium: implications for endocannabinoid control of hippocampal neural plasticity. Neuropharmacology 2011; 60:944-52. [PMID: 21288475 DOI: 10.1016/j.neuropharm.2011.01.039] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2010] [Revised: 01/20/2011] [Accepted: 01/24/2011] [Indexed: 01/06/2023]
Abstract
Chronic activation or inhibition of cannabinoid receptors (CB1) leads to continuous suppression of neuronal plasticity in hippocampus and other brain regions, suggesting that endocannabinoids may have a functional role in synaptic processes that produce state-dependent transient modulation of hippocampal cell activity. In support of this, it has previously been shown in vitro that cannabinoid CB1 receptors modulate second messenger systems in hippocampal neurons that can regulate operation of intracellular processes including receptors which release calcium from intracellular stores. Here we demonstrate in hippocampal slices a similar endocannabinoid action on excitatory glutamatergic synapses via modulation of NMDA-receptor mediated intracellular calcium levels in confocal imaged neurons. Calcium entry through glutamatergic NMDA-mediated ion channels increases intracellular calcium concentrations by modifying release from ryanodine-sensitive channels in endoplasmic reticulum. The studies reported here show that NMDA-elicited increases in Calcium Green fluorescence are enhanced by CB1 receptor antagonists (i.e., Rimonabant), and inhibited by CB1 agonists (i.e., WIN 55,212-2). Suppression of endocannabinoid breakdown by either reuptake inhibition (AM404) or fatty-acid amide hydrolase inhibition (URB597) produced suppression of NMDA-elicited calcium increases comparable to WIN 55,212-2, while enhancement of calcium release provoked by endocannabinoid receptor antagonists (Rimonabant) was shown to depend on the blockade of CB1receptor mediated de-phosphorylation of Ryanodine receptors. Such CB1 receptor modulation of NMDA elicited increases in intracellular calcium may account for the respective disruption and enhancement by CB1 agents of trial-specific hippocampal neuron ensemble firing patterns during performance of a short-term memory task, reported previously from this laboratory.
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Affiliation(s)
- Robert E Hampson
- Dept. of Physiology & Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
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50
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Ludányi A, Hu SSJ, Yamazaki M, Tanimura A, Piomelli D, Watanabe M, Kano M, Sakimura K, Maglóczky Z, Mackie K, Freund TF, Katona I. Complementary synaptic distribution of enzymes responsible for synthesis and inactivation of the endocannabinoid 2-arachidonoylglycerol in the human hippocampus. Neuroscience 2010; 174:50-63. [PMID: 21035522 DOI: 10.1016/j.neuroscience.2010.10.062] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 10/08/2010] [Accepted: 10/21/2010] [Indexed: 01/07/2023]
Abstract
Clinical and experimental evidence demonstrates that endocannabinoids play either beneficial or adverse roles in many neurological and psychiatric disorders. Their medical significance may be best explained by the emerging concept that endocannabinoids are essential modulators of synaptic transmission throughout the central nervous system. However, the precise molecular architecture of the endocannabinoid signaling machinery in the human brain remains elusive. To address this issue, we investigated the synaptic distribution of metabolic enzymes for the most abundant endocannabinoid molecule, 2-arachidonoylglycerol (2-AG), in the postmortem human hippocampus. Immunostaining for diacylglycerol lipase-α (DGL-α), the main synthesizing enzyme of 2-AG, resulted in a laminar pattern corresponding to the termination zones of glutamatergic pathways. The highest density of DGL-α-immunostaining was observed in strata radiatum and oriens of the cornu ammonis and in the inner third of stratum moleculare of the dentate gyrus. At higher magnification, DGL-α-immunopositive puncta were distributed throughout the neuropil outlining the immunonegative main dendrites of pyramidal and granule cells. Electron microscopic analysis revealed that this pattern was due to the accumulation of DGL-α in dendritic spine heads. Similar DGL-α-immunostaining pattern was also found in hippocampi of wild-type, but not of DGL-α knockout mice. Using two independent antibodies developed against monoacylglycerol lipase (MGL), the predominant enzyme inactivating 2-AG, immunostaining also revealed a laminar and punctate staining pattern. However, as observed previously in rodent hippocampus, MGL was enriched in axon terminals instead of postsynaptic structures at the ultrastructural level. Taken together, these findings demonstrate the post- and presynaptic segregation of primary enzymes responsible for synthesis and elimination of 2-AG, respectively, in the human hippocampus. Thus, molecular architecture of the endocannabinoid signaling machinery supports retrograde regulation of synaptic activity, and its similar blueprint in rodents and humans further indicates that 2-AG's physiological role as a negative feed-back signal is an evolutionarily conserved feature of excitatory synapses.
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Affiliation(s)
- A Ludányi
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, H-1083, Szigony utca 43, Hungary
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