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Kędziora M, Boccella S, Marabese I, Mlost J, Infantino R, Maione S, Starowicz K. Inhibition of anandamide breakdown reduces pain and restores LTP and monoamine levels in the rat hippocampus via the CB 1 receptor following osteoarthritis. Neuropharmacology 2023; 222:109304. [PMID: 36341807 DOI: 10.1016/j.neuropharm.2022.109304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 07/15/2022] [Accepted: 10/23/2022] [Indexed: 11/06/2022]
Abstract
Chronic pain is a persistent, complex condition that contributes to impaired mood, anxiety and emotional problems. Osteoarthritis (OA) is one of the major causes of chronic pain in adults and elderly people. A substantial body of evidence demonstrate that hippocampal neural circuits, especially monoamine dopamine and serotonin levels, contributes to negative affect and avoidance motivation experienced during pain. Current pharmacological strategies for OA patients are unsatisfying and the endocannabinoid system modulation might represent an alternative for the treatment of OA-related pain. In the present study, we used a rat model of osteoarthritis induced by intra-articular injection of sodium monoiodoacetate to assess, 28 days post-induction, the contribution of endocannabinoid system on the possible alteration in pain perception and affective behavior, in LTP and monoamine levels in the lateral entorhinal cortex-dentate gyrus pathway. The results show that OA-related chronic pain induces working memory impairment and depressive-like behavior appearance, diminishes LTP, decreases dopamine levels and increases serotonin levels in the rat dentate gyrus. URB597 administration (i.p., 1 mg/kg) reduces hyperalgesia and mechanical allodynia, improves recognition memory and depressive-live behavior, restores LTP and normalizes monoamine levels in the hippocampus. The effect was observed 60-120 min post-treatment and was blocked by AM251, which proves the action of URB597 via the CB1 receptor. Therefore, our study confirms the role of anandamide in OA-related chronic pain management at the behavioral and hippocampal levels. This article is part of the Special Issue on 'Advances in mechanisms and therapeutic targets relevant to pain'.
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Affiliation(s)
- Marta Kędziora
- Department of Neurochemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Cracow, Poland
| | - Serena Boccella
- Department of Experimental Medicine, Division of Pharmacology, University of Campania "L. Vanvitelli", Naples, Italy
| | - Ida Marabese
- Department of Experimental Medicine, Division of Pharmacology, University of Campania "L. Vanvitelli", Naples, Italy
| | - Jakub Mlost
- Department of Neurochemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Cracow, Poland
| | - Rosmara Infantino
- Department of Experimental Medicine, Division of Pharmacology, University of Campania "L. Vanvitelli", Naples, Italy
| | - Sabatino Maione
- Department of Experimental Medicine, Division of Pharmacology, University of Campania "L. Vanvitelli", Naples, Italy; IRCSS, Neuromed, Pozzilli (IS), 86077, Italy; ERG, Endocannabinoid Research Group, CNR, Pozzuoli, Italy
| | - Katarzyna Starowicz
- Department of Neurochemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Cracow, Poland.
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2
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Bourke SL, Schlag AK, O'Sullivan SE, Nutt DJ, Finn DP. Cannabinoids and the endocannabinoid system in fibromyalgia: A review of preclinical and clinical research. Pharmacol Ther 2022; 240:108216. [PMID: 35609718 DOI: 10.1016/j.pharmthera.2022.108216] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 05/03/2022] [Accepted: 05/17/2022] [Indexed: 12/14/2022]
Abstract
Characterised by chronic widespread musculoskeletal pain, generalised hyperalgesia, and psychological distress, fibromyalgia (FM) is a significant unmet clinical need. The endogenous cannabinoid system plays an important role in modulating both pain and the stress response. Here, we appraise the evidence, from preclinical and clinical studies, for a role of the endocannabinoid system in FM and the therapeutic potential of targeting the endocannabinoid system. While many animal models have been used to study FM, the reserpine-induced myalgia model has emerged as perhaps the most translatable to the clinical phenotype. Inhibition of fatty acid amide hydrolase (FAAH) has shown promise in preclinical studies, ameliorating pain- and anxiety-related behaviour . Clinically, there is evidence for alterations in the endocannabinoid system in patients with FM, including single nucleotide polymorphisms and increased levels of circulating endocannabinoids and related N-acylethanolamines. Single entity cannabinoids, cannabis, and cannabis-based medicines in patients with FM show promise therapeutically but limitations in methodology and lack of longitudinal studies to assess efficacy and tolerability preclude the current recommendation for their use in patients with FM. Gaps in the literature that warrant further investigation are discussed, particularly the need for further development of animal models with high validity for the multifaceted nature of FM, balanced studies to eliminate sex-bias in preclinical research, and ultimately, better translation between preclinical and clinical research.
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Affiliation(s)
- Stephanie L Bourke
- Pharmacology and Therapeutics, School of Medicine, Centre for Pain Research and Galway Neuroscience Centre, National University of Ireland, Galway, Ireland
| | - Anne Katrin Schlag
- Drug Science, St. Peters House, Wood Street, London, UK; Faculty of Medicine, Department of Brain Sciences, Imperial College London, UK
| | | | - David J Nutt
- Drug Science, St. Peters House, Wood Street, London, UK; Faculty of Medicine, Department of Brain Sciences, Imperial College London, UK
| | - David P Finn
- Pharmacology and Therapeutics, School of Medicine, Centre for Pain Research and Galway Neuroscience Centre, National University of Ireland, Galway, Ireland.
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3
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Ferrarini EG, Paes RS, Baldasso GM, de Assis PM, Gouvêa MC, Cicco PD, Raposo NRB, Capasso R, Moreira ELG, Dutra RC. Broad-spectrum cannabis oil ameliorates reserpine-induced fibromyalgia model in mice. Biomed Pharmacother 2022; 154:113552. [PMID: 35988425 DOI: 10.1016/j.biopha.2022.113552] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/28/2022] [Accepted: 08/14/2022] [Indexed: 01/25/2023] Open
Abstract
Fibromyalgia (FM) is an idiopathic disorder characterized by generalized pain and associated symptoms such as depression and anxiety. Cannabis sativa shows different pharmacological activities, such as analgesic, anti-inflammatory, neuroprotective, and immunomodulatory. Associated with this, the use of an oil with low concentrations of THC can reduce the psychomimetic adverse effects of the plant. Therefore, the present study aimed to evaluate the analgesic effect of broad-spectrum cannabis oil with low THC concentration in an experimental model of FM. Mechanical hyperalgesia, thermal allodynia, depressive- and anxious-related behavior, and locomotor activity were evaluated after reserpine (0.25 mg/kg; injected subcutaneously (s.c.) once daily for three consecutive days) administration. Our results showed that oral administration of broad-spectrum cannabis oil (0.1, 1, and 3 mg/kg, p.o.) in a single dose on the 4th day inhibited mechanical hyperalgesia and thermal allodynia induced by reserpine. Relevantly, treatment during four days with broad-spectrum cannabis oil (0.1 mg/kg, p.o.) reduced mechanical hyperalgesia 1 h after reserpine administration. Intraplantar treatment with cannabis oil significantly reversed mechanical and heat thermal nociception induced by reserpine injection. Interestingly, spinal and supraspinal administration of broad-spectrum cannabis oil completely inhibited mechanical hyperalgesia and thermal sensitivity induced by reserpine. The repeated cannabis oil administration, given daily for 14 days, markedly mitigated the mechanical and thermal sensitivity during the FM model, and its reduced depressive-like behavior induced by reserpine. In summary, broad-spectrum cannabis oil is an effective alternative to reverse the reserpine-induced fibromyalgia model.
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Affiliation(s)
- Eduarda Gomes Ferrarini
- Laboratory of Autoimmunity and Immunopharmacology, Department of Health Sciences, Campus Araranguá, Universidade Federal de Santa Catarina, 88906-072 Araranguá, SC, Brazil; Post-Graduate Program of Neuroscience, Center of Biological Sciences, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC, Brazil.
| | - Rodrigo Sebben Paes
- Laboratory of Autoimmunity and Immunopharmacology, Department of Health Sciences, Campus Araranguá, Universidade Federal de Santa Catarina, 88906-072 Araranguá, SC, Brazil.
| | - Gabriela Mantovani Baldasso
- Laboratory of Autoimmunity and Immunopharmacology, Department of Health Sciences, Campus Araranguá, Universidade Federal de Santa Catarina, 88906-072 Araranguá, SC, Brazil.
| | - Pollyana Mendonça de Assis
- Center of Research and Innovation in Health Sciences, School of Pharmacy, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, MG, Brazil.
| | - Murilo Chaves Gouvêa
- Associação Brasileira de Apoio Cannabis e Esperança, Parque Sólon de Lucena, 697, 58028-470 João Pessoa, PB, Brazil.
| | - Paola De Cicco
- Department of Pharmacy, University of Naples Federico II, 80131 Naples, Italy.
| | - Nádia Rezende Barbosa Raposo
- Center of Research and Innovation in Health Sciences, School of Pharmacy, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, MG, Brazil.
| | - Raffaele Capasso
- Department of Agricultural Sciences, University of Naples Federico II, 80055 Portici, Italy.
| | - Eduardo Luiz Gasnhar Moreira
- Post-Graduate Program of Neuroscience, Center of Biological Sciences, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC, Brazil.
| | - Rafael Cypriano Dutra
- Laboratory of Autoimmunity and Immunopharmacology, Department of Health Sciences, Campus Araranguá, Universidade Federal de Santa Catarina, 88906-072 Araranguá, SC, Brazil; Post-Graduate Program of Neuroscience, Center of Biological Sciences, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC, Brazil.
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4
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Shang Y, Wang M, Hao Q, Meng T, Li L, Shi J, Yang G, Zhang Z, Yang K, Wang J. Development of indole-2-carbonyl piperazine urea derivatives as selective FAAH inhibitors for efficient treatment of depression and pain. Bioorg Chem 2022; 128:106031. [DOI: 10.1016/j.bioorg.2022.106031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 07/10/2022] [Accepted: 07/12/2022] [Indexed: 11/02/2022]
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Finn DP, Haroutounian S, Hohmann AG, Krane E, Soliman N, Rice ASC. Cannabinoids, the endocannabinoid system, and pain: a review of preclinical studies. Pain 2021; 162:S5-S25. [PMID: 33729211 PMCID: PMC8819673 DOI: 10.1097/j.pain.0000000000002268] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 03/10/2021] [Indexed: 12/13/2022]
Abstract
ABSTRACT This narrative review represents an output from the International Association for the Study of Pain's global task force on the use of cannabis, cannabinoids, and cannabis-based medicines for pain management, informed by our companion systematic review and meta-analysis of preclinical studies in this area. Our aims in this review are (1) to describe the value of studying cannabinoids and endogenous cannabinoid (endocannabinoid) system modulators in preclinical/animal models of pain; (2) to discuss both pain-related efficacy and additional pain-relevant effects (adverse and beneficial) of cannabinoids and endocannabinoid system modulators as they pertain to animal models of pathological or injury-related persistent pain; and (3) to identify important directions for future research. In service of these goals, this review (1) provides an overview of the endocannabinoid system and the pharmacology of cannabinoids and endocannabinoid system modulators, with specific relevance to animal models of pathological or injury-related persistent pain; (2) describes pharmacokinetics of cannabinoids in rodents and humans; and (3) highlights differences and discrepancies between preclinical and clinical studies in this area. Preclinical (rodent) models have advanced our understanding of the underlying sites and mechanisms of action of cannabinoids and the endocannabinoid system in suppressing nociceptive signaling and behaviors. We conclude that substantial evidence from animal models supports the contention that cannabinoids and endocannabinoid system modulators hold considerable promise for analgesic drug development, although the challenge of translating this knowledge into clinically useful medicines is not to be underestimated.
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Affiliation(s)
- David P Finn
- Pharmacology and Therapeutics, School of Medicine, Galway Neuroscience Centre and Centre for Pain Research, Human Biology Building, National University of Ireland Galway, University Road, Galway, Ireland
| | - Simon Haroutounian
- Department of Anesthesiology and Washington University Pain Center, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
| | - Andrea G Hohmann
- Psychological and Brain Sciences, Program in Neuroscience, and Gill Center for Biomolecular Science, Indiana University, Bloomington, IN, USA
| | - Elliot Krane
- Departments of Anesthesiology, Perioperative, and Pain Medicine, & Pediatrics, Stanford University School of Medicine, Stanford, California, USA
| | - Nadia Soliman
- Pain Research, Department of Surgery & Cancer, Faculty of Medicine, Imperial College London, UK
| | - Andrew SC Rice
- Pain Research, Department of Surgery & Cancer, Faculty of Medicine, Imperial College London, UK
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Diester CM, Lichtman AH, Negus SS. Behavioral Battery for Testing Candidate Analgesics in Mice. II. Effects of Endocannabinoid Catabolic Enzyme Inhibitors and ∆9-Tetrahydrocannabinol. J Pharmacol Exp Ther 2021; 377:242-253. [PMID: 33622769 PMCID: PMC8058502 DOI: 10.1124/jpet.121.000497] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 02/22/2021] [Indexed: 12/19/2022] Open
Abstract
Enhanced signaling of the endocannabinoid (eCB) system through inhibition of the catabolic enzymes monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH) has received increasing interest for development of candidate analgesics. This study compared effects of MAGL and FAAH inhibitors with effects of ∆9-tetrahydrocannabinol (THC) using a battery of pain-stimulated, pain-depressed, and pain-independent behaviors in male and female mice. Intraperitoneal injection of dilute lactic acid (IP acid) served as an acute visceral noxious stimulus to stimulate two behaviors (stretching, facial grimace) and depress two behaviors (rearing, nesting). Nesting and locomotion were also assessed in the absence of IP acid as pain-independent behaviors. THC and a spectrum of six eCB catabolic enzyme inhibitors ranging from MAGL- to FAAH-selective were assessed for effectiveness to alleviate pain-related behaviors at doses that did not alter pain-independent behaviors. The MAGL-selective inhibitor MJN110 produced the most effective antinociceptive profile, with 1.0 mg/kg alleviating IP acid effects on stretching, grimace, and nesting without altering pain-independent behaviors. MJN110 effects on IP acid-depressed nesting had a slow onset and long duration (40 minutes to 6 hours), were blocked by rimonabant, and tended to be greater in females. As inhibitors increased in FAAH selectivity, antinociceptive effectiveness decreased. PF3845, the most FAAH-selective inhibitor, produced no antinociception up to doses that disrupted locomotion. THC decreased IP acid-stimulated stretching and grimace at doses that did not alter pain-independent behaviors; however, it did not alleviate IP acid-induced depression of rearing or nesting. These results support further consideration of MAGL-selective inhibitors as candidate analgesics for acute inflammatory pain. SIGNIFICANCE STATEMENT: This study characterized a spectrum of endocannabinoid catabolic enzyme inhibitors ranging in selectivity from monoacylglycerol lipase-selective to fatty acid amide hydrolase-selective in a battery of pain-stimulated, pain-depressed, and pain-independent behaviors previously pharmacologically characterized in a companion paper. This battery provides a method for prioritizing candidate analgesics by effectiveness to alleviate pain-related behaviors at doses that do not alter pain-independent behaviors, with inclusion of pain-depressed behaviors increasing translational validity and decreasing susceptibility to motor-depressant false positives.
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Affiliation(s)
- C M Diester
- Department of Pharmacology and Toxicology (C.M.D., A.H.L., S.S.N.), School of Pharmacy (A.H.L.), Virginia Commonwealth University, Richmond, Virginia
| | - A H Lichtman
- Department of Pharmacology and Toxicology (C.M.D., A.H.L., S.S.N.), School of Pharmacy (A.H.L.), Virginia Commonwealth University, Richmond, Virginia
| | - S S Negus
- Department of Pharmacology and Toxicology (C.M.D., A.H.L., S.S.N.), School of Pharmacy (A.H.L.), Virginia Commonwealth University, Richmond, Virginia
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7
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Apaza Ticona L, Tena Pérez V, Serban AM, Sánchez‐Corral J, Rumbero Sánchez Á. Design, Synthesis and Pharmacological Evaluation of
N
‐Benzyl Linoleamide Analogues from
Tropaeolum tuberosum
as NF‐κB Inhibitors and Nrf2 Activators. ChemistrySelect 2020. [DOI: 10.1002/slct.202003062] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Luis Apaza Ticona
- Department of Organic Chemistry Faculty of Sciences University Autónoma of Madrid Cantoblanco 28049 Madrid Spain
- Department of Pharmacology Pharmacognosy and Botany Faculty of Pharmacy University Complutense of Madrid Ciudad Universitaria s/n 28040 Madrid Spain
| | - Víctor Tena Pérez
- Department of Organic Chemistry Faculty of Sciences University Autónoma of Madrid Cantoblanco 28049 Madrid Spain
| | - Andreea Madalina Serban
- Maria Sklodowska Curie University Hospital for Children Constantin Brancoveanu Boulevard 077120 Bucharest Romania
| | - Javier Sánchez‐Corral
- Department of Organic Chemistry Faculty of Sciences University Autónoma of Madrid Cantoblanco 28049 Madrid Spain
| | - Ángel Rumbero Sánchez
- Department of Organic Chemistry Faculty of Sciences University Autónoma of Madrid Cantoblanco 28049 Madrid Spain
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8
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Cannabinoids affect the mouse visual acuity via the cannabinoid receptor type 2. Sci Rep 2020; 10:15819. [PMID: 32978469 PMCID: PMC7519129 DOI: 10.1038/s41598-020-72553-y] [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: 05/26/2020] [Accepted: 09/02/2020] [Indexed: 12/18/2022] Open
Abstract
Recently, there have been increasing indications that the endocannabinoid (eCB) system is involved in vision. Multiple research teams studied the cannabinoid receptor type 2 (CB2R) expression and function in the mouse retina. Here, we examined the consequence of CB2R modulation on visual acuity using genetic and pharmacologic tools. We found that Cnr2 knockout mice show an enhanced visual acuity, CB2R activation decreased visual acuity while CB2R blockade with the inverse agonist AM630 increased it. The inhibition of 2-arachidonylglycerol (2-AG) synthesis and degradation also greatly increased and decreased visual acuity, respectively. No differences were seen when the cannabinoid receptor type 1 (CB1R) was deleted, blocked or activated implying that CB2R exclusively mediates cannabinoid modulation of the visual acuity. We also investigated the role of cannabinoids in retinal function using electroretinography (ERG). We found that modulating 2-AG levels affected many ERG components, such as the a-wave and oscillatory potentials (OPs), suggesting an impact on cones and amacrine cells. Taken together, these results reveal that CB2R modulates visual acuity and that eCBs such as 2-AG can modulate both visual acuity and retinal sensitivity. Finally, these findings establish that CB2R is present in visual areas and regulates vision-related functions.
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9
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Kaur I, Behl T, Bungau S, Zengin G, Kumar A, El-Esawi MA, Khullar G, Venkatachalam T, Arora S. The endocannabinoid signaling pathway as an emerging target in pharmacotherapy, earmarking mitigation of destructive events in rheumatoid arthritis. Life Sci 2020; 257:118109. [PMID: 32698072 DOI: 10.1016/j.lfs.2020.118109] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/09/2020] [Accepted: 07/13/2020] [Indexed: 02/06/2023]
Abstract
Rheumatoid arthritis is an inflammatory autoimmune disease, characterized by synovial proliferation, destruction to articular cartilage and severe pain. The cannabinoids obtained from Cannabis sativa exhibited their actions via cannabinoid-1 and -2 receptors, which also provides a platform for endocannabinoids to act. The endocannabinoid system comprises endocannabinoid molecules involved in signaling processes, along with G-protein coupled receptors and enzymes associated with ligand biosynthesis, activation and degradation. The action of endocannabinoid system in immune system regulation, via primary CB2 activation, followed by inhibition of production of pro-inflammatory cytokines, auto-antibodies and MMPs, FLSs proliferation and T-cell mediated immune response, are elaborated as potential therapeutic regimes in rheumatoid arthritis. The involvement of endocannabinoid system in immune cells like, B cells, T cells and macrophages, as well as regulatory actions on sensory noniceptors to ameliorate pain is significantly highlighted in the review, elaborating the actions of endocannabinoid signaling in mitigating the disease events. The review also focuses on enhancement of endocannabinoid tone, either by inhibiting the degradation enzymes, like FAAH, MAGL, COX, CytP450, LOX, etc. or by retarding cellular uptake processes. Moreover, the review portrays the optimizing role of endocannabinoid system, in abbreviating the symptoms and complications of rheumatoid arthritis in patients and mitigating inflammation, pain and immune mediated effects significantly.
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Affiliation(s)
- Ishnoor Kaur
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | - Tapan Behl
- Chitkara College of Pharmacy, Chitkara University, Punjab, India.
| | - Simona Bungau
- Department of Pharmacy, Faculty of Medicine and Pharmacy, University of Oradea, 10 1 Decembrie Sq., Oradea, Romania
| | - Gokhan Zengin
- Department of Biology, Faculty of Science, Selcuk University Campus, Konya, Turkey
| | - Arun Kumar
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | | | - Gaurav Khullar
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | | | - Sandeep Arora
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
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10
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González-Cano R, Montilla-García Á, Ruiz-Cantero MC, Bravo-Caparrós I, Tejada MÁ, Nieto FR, Cobos EJ. The search for translational pain outcomes to refine analgesic development: Where did we come from and where are we going? Neurosci Biobehav Rev 2020; 113:238-261. [PMID: 32147529 DOI: 10.1016/j.neubiorev.2020.03.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 02/06/2020] [Accepted: 03/04/2020] [Indexed: 12/11/2022]
Abstract
Pain measures traditionally used in rodents record mere reflexes evoked by sensory stimuli; the results thus may not fully reflect the human pain phenotype. Alterations in physical and emotional functioning, pain-depressed behaviors and facial pain expressions were recently proposed as additional pain outcomes to provide a more accurate measure of clinical pain in rodents, and hence to potentially enhance analgesic drug development. We aimed to review how preclinical pain assessment has evolved since the development of the tail flick test in 1941, with a particular focus on a critical analysis of some nonstandard pain outcomes, and a consideration of how sex differences may affect the performance of these pain surrogates. We tracked original research articles in Medline for the following periods: 1973-1977, 1983-1987, 1993-1997, 2003-2007, and 2014-2018. We identified 606 research articles about alternative surrogate pain measures, 473 of which were published between 2014 and 2018. This indicates that preclinical pain assessment is moving toward the use of these measures, which may soon become standard procedures in preclinical pain laboratories.
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Affiliation(s)
- Rafael González-Cano
- Department of Pharmacology, Faculty of Medicine, University of Granada, Granada, Spain; Institute of Neuroscience, Biomedical Research Center, University of Granada, Armilla, Granada, Spain.
| | - Ángeles Montilla-García
- Department of Pharmacology, Faculty of Medicine, University of Granada, Granada, Spain; Institute of Neuroscience, Biomedical Research Center, University of Granada, Armilla, Granada, Spain.
| | - M Carmen Ruiz-Cantero
- Department of Pharmacology, Faculty of Medicine, University of Granada, Granada, Spain; Institute of Neuroscience, Biomedical Research Center, University of Granada, Armilla, Granada, Spain.
| | - Inmaculada Bravo-Caparrós
- Department of Pharmacology, Faculty of Medicine, University of Granada, Granada, Spain; Institute of Neuroscience, Biomedical Research Center, University of Granada, Armilla, Granada, Spain.
| | - Miguel Á Tejada
- Department of Pharmacology, Faculty of Medicine, University of Granada, Granada, Spain; Institute of Neuroscience, Biomedical Research Center, University of Granada, Armilla, Granada, Spain; IMBA, Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria.
| | - Francisco R Nieto
- Department of Pharmacology, Faculty of Medicine, University of Granada, Granada, Spain; Institute of Neuroscience, Biomedical Research Center, University of Granada, Armilla, Granada, Spain.
| | - Enrique J Cobos
- Department of Pharmacology, Faculty of Medicine, University of Granada, Granada, Spain; Institute of Neuroscience, Biomedical Research Center, University of Granada, Armilla, Granada, Spain; Instituto de Investigación Biosanitaria ibs.GRANADA, Granada, Spain; Teófilo Hernando Institute for Drug Discovery, Madrid, Spain.
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11
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Giacovazzo G, Bisogno T, Piscitelli F, Verde R, Oddi S, Maccarrone M, Coccurello R. Different Routes to Inhibit Fatty Acid Amide Hydrolase: Do All Roads Lead to the Same Place? Int J Mol Sci 2019; 20:ijms20184503. [PMID: 31514437 PMCID: PMC6771131 DOI: 10.3390/ijms20184503] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 09/06/2019] [Accepted: 09/09/2019] [Indexed: 11/25/2022] Open
Abstract
There is robust evidence indicating that enhancing the endocannabinoid (eCB) tone has therapeutic potential in several brain disorders. The inhibition of eCBs degradation by fatty acid amide hydrolase (FAAH) blockade, is the best-known option to increase N-acyl-ethanolamines-(NAEs)-mediated signaling. Here, we investigated the hypothesis that intranasal delivery is an effective route for different FAAH inhibitors, such as URB597 and PF-04457845. URB597 and PF-04457845 were subchronically administered in C57BL/6 male mice every other day for 20 days for overall 10 drug treatment, and compared for their ability to inhibit FAAH activity by the way of three different routes of administration: intranasal (i.n.), intraperitoneal (i.p.) and oral (p.o.). Lastly, we compared the efficacy of the three routes in terms of URB597-induced increase of NAEs levels in liver and in different brain areas. Results: We show that PF-04457845 potently inhibits FAAH regardless the route selected, and that URB597 was less effective in the brain after p.o. administration while reached similar effects by i.n. and i.p. routes. Intranasal URB597 delivery always increased NAEs levels in brain areas, whereas a parallel increase was not observed in the liver. By showing the efficacy of intranasal FAAH inhibition, we provide evidence that nose-to-brain delivery is a suitable alternative to enhance brain eCB tone for the treatment of neurodegenerative disorders and improve patients’ compliance.
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Affiliation(s)
- Giacomo Giacovazzo
- Fondazione Santa Lucia IRCCS, Preclinical Neuroscience, Via del Fosso di Fiorano 64, 00143 Rome, Italy
| | - Tiziana Bisogno
- Endocannabinoid Research Group, Institute of Translational Pharmacology, CNR, Via Fosso del Cavaliere 100, 00133 Rome, Italy
| | - Fabiana Piscitelli
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, CNR, Via C. Flegrei 34, 80078 Pozzuoli, Italy
| | - Roberta Verde
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, CNR, Via C. Flegrei 34, 80078 Pozzuoli, Italy
| | - Sergio Oddi
- Fondazione Santa Lucia IRCCS, Preclinical Neuroscience, Via del Fosso di Fiorano 64, 00143 Rome, Italy
- Faculty of Veterinary Medicine, University of Teramo, via R. Balzarini 1, 64100 Teramo, Italy
| | - Mauro Maccarrone
- Fondazione Santa Lucia IRCCS, Preclinical Neuroscience, Via del Fosso di Fiorano 64, 00143 Rome, Italy.
- Department of Medicine, Campus Bio-Medico University of Rome, Via Alvaro del Portillo 21, 00128 Rome, Italy.
| | - Roberto Coccurello
- Fondazione Santa Lucia IRCCS, Preclinical Neuroscience, Via del Fosso di Fiorano 64, 00143 Rome, Italy.
- Institute for Complex Systems (ISC), C.N.R., Via dei Taurini 19, 00185 Rome, Italy.
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Impaired anandamide/palmitoylethanolamide signaling in hippocampal glutamatergic neurons alters synaptic plasticity, learning, and emotional responses. Neuropsychopharmacology 2019; 44:1377-1388. [PMID: 30532004 PMCID: PMC6784910 DOI: 10.1038/s41386-018-0274-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 10/26/2018] [Accepted: 11/01/2018] [Indexed: 12/28/2022]
Abstract
Endocannabinoid signaling via anandamide (AEA) is implicated in a variety of neuronal functions and considered a promising therapeutic target for numerous emotion-related disorders. The major AEA degrading enzyme is fatty acid amide hydrolase (FAAH). Genetic deletion and pharmacological inhibition of FAAH reduce anxiety and improve emotional responses and memory in rodents and humans. Complementarily, the mechanisms and impact of decreased AEA signaling remain to be delineated in detail. In the present study, using the Cre/loxP system combined with an adeno-associated virus (AAV)-mediated delivery system, FAAH was selectively overexpressed in hippocampal CA1-CA3 glutamatergic neurons of adult mice. This approach led to specific FAAH overexpression at the postsynaptic site of CA1-CA3 neurons, to increased FAAH enzymatic activity, and, in consequence, to decreased hippocampal levels of AEA and palmitoylethanolamide (PEA), but the levels of the second major endocannabinoid 2-arachidonoyl glycerol (2-AG) and of oleoylethanolamide (OEA) were unchanged. Electrophysiological recordings revealed an enhancement of both excitatory and inhibitory synaptic activity and of long-term potentiation (LTP). In contrast, excitatory and inhibitory long-term depression (LTD) and short-term synaptic plasticity, apparent as depolarization-induced suppression of excitation (DSE) and inhibition (DSI), remained unaltered. These changes in hippocampal synaptic activity were associated with an increase in anxiety-like behavior, and a deficit in object recognition memory and in extinction of aversive memory. This study indicates that AEA is not involved in hippocampal short-term plasticity, or eLTD and iLTD, but modulates glutamatergic transmission most likely via presynaptic sites, and that disturbances in this process impair learning and emotional responses.
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Diacylglycerol Lipase-Alpha Regulates Hippocampal-Dependent Learning and Memory Processes in Mice. J Neurosci 2019; 39:5949-5965. [PMID: 31127001 DOI: 10.1523/jneurosci.1353-18.2019] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Revised: 04/24/2019] [Accepted: 05/11/2019] [Indexed: 12/18/2022] Open
Abstract
Diacylglycerol lipase-α (DAGL-α), the principal biosynthetic enzyme of the endogenous cannabinoid 2-arachidonylglycerol (2-AG) on neurons, plays a key role in CB1 receptor-mediated synaptic plasticity and hippocampal neurogenesis, but its contribution to global hippocampal-mediated processes remains unknown. Thus, the present study examines the role that DAGL-α plays on LTP in hippocampus, as well as in hippocampal-dependent spatial learning and memory tasks, and on the production of endocannabinoid and related lipids through the use of complementary pharmacologic and genetic approaches to disrupt this enzyme in male mice. Here we show that DAGL-α gene deletion or pharmacological inhibition disrupts LTP in CA1 of the hippocampus but elicits varying magnitudes of behavioral learning and memory deficits in mice. In particular, DAGL-α-/- mice display profound impairments in the Object Location assay and Morris Water Maze (MWM) acquisition engaging in nonspatial search strategies. In contrast, WT mice administered the DAGL-α inhibitor DO34 show delays in MWM acquisition and reversal learning, but no deficits in expression, extinction, forgetting, or perseveration processes in this task, as well as no impairment in Object Location. The deficits in synaptic plasticity and MWM performance occur in concert with decreased 2-AG and its major lipid metabolite (arachidonic acid), but increases of a 2-AG diacylglycerol precursor in hippocampus, PFC, striatum, and cerebellum. These novel behavioral and electrophysiological results implicate a direct and perhaps selective role of DAGL-α in the integration of new spatial information.SIGNIFICANCE STATEMENT Here we show that genetic deletion or pharmacologic inhibition of diacylglycerol lipase-α (DAGL-α) impairs hippocampal CA1 LTP, differentially disrupts spatial learning and memory performance in Morris water maze (MWM) and Object Location tasks, and alters brain levels of endocannabinoids and related lipids. Whereas DAGL-α-/- mice exhibit profound phenotypic spatial memory deficits, a DAGL inhibitor selectively impairs the integration of new information in MWM acquisition and reversal tasks, but not memory processes of expression, extinction, forgetting, or perseveration, and does not affect performance in the Objection Location task. The findings that constitutive or short-term DAGL-α disruption impairs learning and memory at electrophysiological and selective in vivo levels implicate this enzyme as playing a key role in the integration of new spatial information.
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Scherma M, Masia P, Satta V, Fratta W, Fadda P, Tanda G. Brain activity of anandamide: a rewarding bliss? Acta Pharmacol Sin 2019; 40:309-323. [PMID: 30050084 DOI: 10.1038/s41401-018-0075-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 05/20/2018] [Indexed: 12/11/2022] Open
Abstract
Anandamide is a lipid mediator that acts as an endogenous ligand of CB1 receptors. These receptors are also the primary molecular target responsible for the pharmacological effects of Δ9-tetrahydrocannabinol, the psychoactive ingredient in Cannabis sativa. Several studies demonstrate that anandamide exerts an overall modulatory effect on the brain reward circuitry. Several reports suggest its involvement in the addiction-producing actions of other abused drugs, and it can also act as a behavioral reinforcer in animal models of drug abuse. Importantly, all these effects of anandamide appear to be potentiated by pharmacological inhibition of its metabolic degradation. Enhanced brain levels of anandamide after treatment with inhibitors of fatty acid amide hydrolase, the main enzyme responsible for its degradation, seem to affect the rewarding and reinforcing actions of many drugs of abuse. In this review, we will provide an overview from a preclinical perspective of the current state of knowledge regarding the behavioral pharmacology of anandamide, with a particular emphasis on its motivational/reinforcing properties. We will also discuss how modulation of anandamide levels through inhibition of enzymatic metabolic pathways could provide a basis for developing new pharmaco-therapeutic tools for the treatment of substance use disorders.
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Abstract
A great need exists for the identification of new effective analgesics to treat sustained pain. However, most preclinical nociceptive assays measure behavioral responses evoked by noxious stimuli (ie, pain-stimulated behavior), which presents a challenge to distinguish between motor impairing and antinociceptive effects of drugs. Here, we demonstrate that chronic constriction injury (CCI) of the sciatic nerve elicits common pain-stimulated responses (ie, mechanical allodynia and thermal hyperalgesia) as well as reduces marble burying/digging behaviors that occur during the early stages of the neuropathy and resolve within 1 week. Although drugs representing distinct classes of analgesics (ie, morphine, valdecoxib, and gabapentin) reversed both CCI-induced and CCI-depressed nociceptive measures, diazepam lacked antinociceptive effects in all assays and the kappa-opioid receptor agonist U69593 reversed pain-stimulated, but not pain-depressed behaviors. In addition, we tested drugs targeting distinct components of the endocannabinoid system, including agonists at cannabinoid receptors type 1 (CB1) and type 2 (CB2), as well as inhibitors of the endocannabinoid-regulating enzymes fatty acid amide hydrolase and monoacylglycerol lipase. Each of these drugs reversed all CCI-induced nociceptive measures, with the exception of the fatty acid amide hydrolase inhibitor that reversed pain-stimulated behaviors, only. These findings support the use of the mouse marble-burying assay as a model of pain-depressed behavior within the first week of sciatic nerve injury to examine candidate analgesics. These data also support existing preclinical research that cannabinoid receptor agonists and inhibitors of endocannabinoid-regulating enzymes merit consideration for the treatment of pain.
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Slivicki RA, Saberi SA, Iyer V, Vemuri VK, Makriyannis A, Hohmann AG. Brain-Permeant and -Impermeant Inhibitors of Fatty Acid Amide Hydrolase Synergize with the Opioid Analgesic Morphine to Suppress Chemotherapy-Induced Neuropathic Nociception Without Enhancing Effects of Morphine on Gastrointestinal Transit. J Pharmacol Exp Ther 2018; 367:551-563. [PMID: 30275151 DOI: 10.1124/jpet.118.252288] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 09/28/2018] [Indexed: 01/15/2023] Open
Abstract
Opioid-based therapies remain a mainstay for chronic pain management, but unwanted side effects limit therapeutic use. We compared efficacies of brain-permeant and -impermeant inhibitors of fatty acid amide hydrolase (FAAH) in suppressing neuropathic pain induced by the chemotherapeutic agent paclitaxel. Paclitaxel produced mechanical and cold allodynia without altering nestlet shredding or marble burying behaviors. We compared FAAH inhibitors that differ in their ability to penetrate the central nervous system for antiallodynic efficacy, pharmacological specificity, and synergism with the opioid analgesic morphine. (3'-(aminocarbonyl)[1,1'-biphenyl]- 3-yl)-cyclohexylcarbamate (URB597), a brain-permeant FAAH inhibitor, attenuated paclitaxel-induced allodynia via cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2) mechanisms. URB937, a brain-impermeant FAAH inhibitor, suppressed paclitaxel-induced allodynia through a CB1 mechanism only. 5-[4-(4-cyano-1-butyn-1-yl)phenyl]-1-(2,4-dichlorophenyl)-N-(1,1-dioxido-4-thiomorpholinyl)-4-methyl-1H-pyrazole-3-carboxamide (AM6545), a peripherally restricted CB1 antagonist, fully reversed the antiallodynic efficacy of N-cyclohexyl-carbamic acid, 3'-(aminocarbonyl)-6-hydroxy[1,1'- biphenyl]-3-yl ester (URB937) but only partially reversed that of URB597. Thus, URB937 suppressed paclitaxel-induced allodynia through a mechanism that was dependent upon peripheral CB1 receptor activation only. Antiallodynic effects of both FAAH inhibitors were reversed by N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (AM251). Antiallodynic effects of URB597, but not URB937, were reversed by 6-iodo-2-methyl-1-[2-(4-morpholinyl)ethyl]-1H-indol-3-yl](4-methoxyphenyl)methanone (AM630). Isobolographic analysis revealed synergistic interactions between morphine and either URB597 or URB937 in reducing paclitaxel-induced allodynia. A leftward shift in the dose-response curve of morphine antinociception was observed when morphine was coadministered with either URB597 or URB937, consistent with morphine sparing. However, neither URB937 nor URB597 enhanced morphine-induced deficits in colonic transit. Thus, our findings suggest that FAAH inhibition may represent a therapeutic avenue to reduce the overall amount of opioid needed for treating neuropathic pain with potential to reduce unwanted side effects that accompany opioid administration.
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Affiliation(s)
- Richard A Slivicki
- Program in Neuroscience (R.A.S., V.I., A.G.H.), Department of Psychological and Brain Sciences (R.A.S., S.A.S., V.I., A.G.H.), and Gill Center for Biomolecular Science (A.G.H.), Indiana University, Bloomington, Indiana; and Center for Drug Discovery, Northeastern University, Boston, Massachusetts (V.K.V., A.M.)
| | - Shahin A Saberi
- Program in Neuroscience (R.A.S., V.I., A.G.H.), Department of Psychological and Brain Sciences (R.A.S., S.A.S., V.I., A.G.H.), and Gill Center for Biomolecular Science (A.G.H.), Indiana University, Bloomington, Indiana; and Center for Drug Discovery, Northeastern University, Boston, Massachusetts (V.K.V., A.M.)
| | - Vishakh Iyer
- Program in Neuroscience (R.A.S., V.I., A.G.H.), Department of Psychological and Brain Sciences (R.A.S., S.A.S., V.I., A.G.H.), and Gill Center for Biomolecular Science (A.G.H.), Indiana University, Bloomington, Indiana; and Center for Drug Discovery, Northeastern University, Boston, Massachusetts (V.K.V., A.M.)
| | - V Kiran Vemuri
- Program in Neuroscience (R.A.S., V.I., A.G.H.), Department of Psychological and Brain Sciences (R.A.S., S.A.S., V.I., A.G.H.), and Gill Center for Biomolecular Science (A.G.H.), Indiana University, Bloomington, Indiana; and Center for Drug Discovery, Northeastern University, Boston, Massachusetts (V.K.V., A.M.)
| | - Alexandros Makriyannis
- Program in Neuroscience (R.A.S., V.I., A.G.H.), Department of Psychological and Brain Sciences (R.A.S., S.A.S., V.I., A.G.H.), and Gill Center for Biomolecular Science (A.G.H.), Indiana University, Bloomington, Indiana; and Center for Drug Discovery, Northeastern University, Boston, Massachusetts (V.K.V., A.M.)
| | - Andrea G Hohmann
- Program in Neuroscience (R.A.S., V.I., A.G.H.), Department of Psychological and Brain Sciences (R.A.S., S.A.S., V.I., A.G.H.), and Gill Center for Biomolecular Science (A.G.H.), Indiana University, Bloomington, Indiana; and Center for Drug Discovery, Northeastern University, Boston, Massachusetts (V.K.V., A.M.)
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Endocannabinoids in Body Weight Control. Pharmaceuticals (Basel) 2018; 11:ph11020055. [PMID: 29849009 PMCID: PMC6027162 DOI: 10.3390/ph11020055] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 05/17/2018] [Accepted: 05/28/2018] [Indexed: 12/15/2022] Open
Abstract
Maintenance of body weight is fundamental to maintain one's health and to promote longevity. Nevertheless, it appears that the global obesity epidemic is still constantly increasing. Endocannabinoids (eCBs) are lipid messengers that are involved in overall body weight control by interfering with manifold central and peripheral regulatory circuits that orchestrate energy homeostasis. Initially, blocking of eCB signaling by first generation cannabinoid type 1 receptor (CB1) inverse agonists such as rimonabant revealed body weight-reducing effects in laboratory animals and men. Unfortunately, rimonabant also induced severe psychiatric side effects. At this point, it became clear that future cannabinoid research has to decipher more precisely the underlying central and peripheral mechanisms behind eCB-driven control of feeding behavior and whole body energy metabolism. Here, we will summarize the most recent advances in understanding how central eCBs interfere with circuits in the brain that control food intake and energy expenditure. Next, we will focus on how peripheral eCBs affect food digestion, nutrient transformation and energy expenditure by interfering with signaling cascades in the gastrointestinal tract, liver, pancreas, fat depots and endocrine glands. To finally outline the safe future potential of cannabinoids as medicines, our overall goal is to address the molecular, cellular and pharmacological logic behind central and peripheral eCB-mediated body weight control, and to figure out how these precise mechanistic insights are currently transferred into the development of next generation cannabinoid medicines displaying clearly improved safety profiles, such as significantly reduced side effects.
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Enhanced endocannabinoid tone as a potential target of pharmacotherapy. Life Sci 2018; 204:20-45. [PMID: 29729263 DOI: 10.1016/j.lfs.2018.04.054] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/19/2018] [Accepted: 04/28/2018] [Indexed: 12/21/2022]
Abstract
The endocannabinoid system is up-regulated in numerous pathophysiological states such as inflammatory, neurodegenerative, gastrointestinal, metabolic and cardiovascular diseases, pain, and cancer. It has been suggested that this phenomenon primarily serves an autoprotective role in inhibiting disease progression and/or diminishing signs and symptoms. Accordingly, enhancement of endogenous endocannabinoid tone by inhibition of endocannabinoid degradation represents a promising therapeutic approach for the treatment of many diseases. Importantly, this allows for the avoidance of unwanted psychotropic side effects that accompany exogenously administered cannabinoids. The effects of endocannabinoid metabolic pathway modulation are complex, as endocannabinoids can exert their actions directly or via numerous metabolites. The two main strategies for blocking endocannabinoid degradation are inhibition of endocannabinoid-degrading enzymes and inhibition of endocannabinoid cellular uptake. To date, the most investigated compounds are inhibitors of fatty acid amide hydrolase (FAAH), an enzyme that degrades the endocannabinoid anandamide. However, application of FAAH inhibitors (and consequently other endocannabinoid degradation inhibitors) in medicine became questionable due to a lack of therapeutic efficacy in clinical trials and serious adverse effects evoked by one specific compound. In this paper, we discuss multiple pathways of endocannabinoid metabolism, changes in endocannabinoid levels across numerous human diseases and corresponding experimental models, pharmacological strategies for enhancing endocannabinoid tone and potential therapeutic applications including multi-target drugs with additional targets outside of the endocannabinoid system (cyclooxygenase-2, cholinesterase, TRPV1, and PGF2α-EA receptors), and currently used medicines or medicinal herbs that additionally enhance endocannabinoid levels. Ultimately, further clinical and preclinical studies are warranted to develop medicines for enhancing endocannabinoid tone.
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Poddighe L, Carta G, Serra MP, Melis T, Boi M, Lisai S, Murru E, Muredda L, Collu M, Banni S, Quartu M. Acute administration of beta-caryophyllene prevents endocannabinoid system activation during transient common carotid artery occlusion and reperfusion. Lipids Health Dis 2018; 17:23. [PMID: 29402275 PMCID: PMC5799897 DOI: 10.1186/s12944-018-0661-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 01/12/2018] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND The transient global cerebral hypoperfusion/reperfusion achieved by induction of Bilateral Common Carotid Artery Occlusion followed by Reperfusion (BCCAO/R) has been shown to stimulate early molecular changes that can be easily traced in brain tissue and plasma, and that are indicative of the tissue physiological response to the reperfusion-induced oxidative stress and inflammation. The aim of the present study is to probe the possibility to prevent the molecular changes induced by the BCCAO/R with dietary natural compounds known to possess anti-inflammatory activity, such as the phytocannabinoid beta-caryophyllene (BCP). METHODS Two groups of adult Wistar rats were used, sham-operated and submitted to BCCAO/R. In both groups, 6 h before surgery, half of the rats were gavage-fed with a single dose of BCP (40 mg/per rat in 300 μl of sunflower oil as vehicle), while the second half were pre-treated with the vehicle alone. HPLC, Western Blot and immunohistochemistry were used to analyze cerebral cortex and plasma. RESULTS After BCCAO/R, BCP prevented the increase of lipoperoxides occurring in the vehicle-treated rats in both cerebral cortex and plasma. In the frontal cortex, BCP further prevented activation of the endocannabinoid system (ECS), spared the docosahexaenoic acid (DHA), appeared to prevent the increase of cyclooxygenase-2 and increased the peroxisome-proliferator activated receptor-alpha (PPAR-alpha) protein levels, while, in plasma, BCP induced the reduction of arachidonoylethanolamide (AEA) levels as compared to vehicle-treated rats. CONCLUSIONS Collectively, the pre-treatment with BCP, likely acting as agonist for CB2 and PPAR-alpha receptors, modulates in a beneficial way the ECS activation and the lipoperoxidation, taken as indicative of oxidative stress. Furthermore, our results support the evidence that BCP may be used as a dietary supplement to control the physiological response to the hypoperfusion/reperfusion-induced oxidative stress.
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Affiliation(s)
- Laura Poddighe
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, (CA) 09042 Italy
| | - Gianfranca Carta
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, (CA) 09042 Italy
| | - Maria Pina Serra
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, (CA) 09042 Italy
| | - Tiziana Melis
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, (CA) 09042 Italy
| | - Marianna Boi
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, (CA) 09042 Italy
| | - Sara Lisai
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, (CA) 09042 Italy
| | - Elisabetta Murru
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, (CA) 09042 Italy
| | - Laura Muredda
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, (CA) 09042 Italy
| | - Maria Collu
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, (CA) 09042 Italy
| | - Sebastiano Banni
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, (CA) 09042 Italy
| | - Marina Quartu
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, (CA) 09042 Italy
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Lazenka MF, Freitas KC, Henck S, Negus SS. Relief of Pain-Depressed Behavior in Rats by Activation of D1-Like Dopamine Receptors. J Pharmacol Exp Ther 2017; 362:14-23. [PMID: 28411257 DOI: 10.1124/jpet.117.240796] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 04/13/2017] [Indexed: 12/11/2022] Open
Abstract
Clinically significant pain often includes a decrease in both behavior and mesolimbic dopamine signaling. Indirect and/or direct dopamine receptor agonists may alleviate pain-related behavioral depression. To test this hypothesis, the present study compared effects of indirect and direct dopamine agonists in a preclinical assay of pain-depressed operant responding. Male Sprague-Dawley rats with chronic indwelling microelectrodes in the medial forebrain bundle were trained in an intracranial self-stimulation (ICSS) procedure to press a lever for pulses of electrical brain stimulation. Intraperitoneal injection of dilute lactic acid served as an acute noxious stimulus to depress ICSS. Intraperitoneal lactic acid-induced depression of ICSS was dose-dependently blocked by the dopamine transporter inhibitor methylphenidate and the D1-selective agonist SKF82958, but not by the D2/3-selective agonists quinpirole, pramipexole, or sumanirole. The antinociceptive effects of methylphenidate and SKF82958 were blocked by the D1-selective antagonist SCH39166. Acid-induced stimulation of a stretching response was evaluated in separate groups of rats, but all agonists decreased acid-stimulated stretching, and antagonism experiments were inconclusive due to direct effects of the antagonists when administered alone. Taken together, these results suggest that D1-receptor stimulation is both sufficient to block acid-induced depression of ICSS and necessary for methylphenidate antinociception in this procedure. Conversely, D2/3-receptor stimulation is not sufficient to relieve pain-depressed behavior. These results support the hypothesis that pain-related depression of dopamine D1 receptor signaling contributes to pain-related depression of behavior in rats. Additionally, these results support further consideration of indirect dopamine agonists and direct D1 receptor agonists as candidate treatments for pain-related behavioral depression.
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Affiliation(s)
- Matthew F Lazenka
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Kelen C Freitas
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Sydney Henck
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - S Stevens Negus
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
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Hillhouse TM, Negus SS. Effects of the noncompetitive N-methyl-d-aspartate receptor antagonists ketamine and MK-801 on pain-stimulated and pain-depressed behaviour in rats. Eur J Pain 2016; 20:1229-40. [PMID: 26914635 DOI: 10.1002/ejp.847] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/01/2016] [Indexed: 12/22/2022]
Abstract
BACKGROUND Pain is a significant public health concern, and current pharmacological treatments have problematic side effects and limited effectiveness. N-methyl-d-aspartate (NMDA) glutamate receptor antagonists have emerged as one class of candidate treatments for pain because of the significant contribution of glutamate signalling in nociceptive processing. METHODS This study compared effects of the NMDA receptor antagonists ketamine and MK-801 in assays of pain-stimulated and pain-depressed behaviour in rats. The nonsteroidal anti-inflammatory drug ketoprofen was examined for comparison as a positive control. Intraperitoneal injection of dilute acid served as an acute visceral noxious stimulus to stimulate a stretching response or depress intracranial self-stimulation (ICSS) in male Sprague-Dawley rats. RESULTS Ketamine (1.0-10.0 mg/kg) blocked acid-stimulated stretching but failed to block acid-induced depression of ICSS, whereas MK-801 (0.01-0.1 mg/kg) blocked both acid-stimulated stretching and acid-induced depression of ICSS. These doses of ketamine and MK-801 did not alter control ICSS in the absence of the noxious stimulus; however, higher doses of ketamine (10 mg/kg) and MK-801 (0.32 mg/kg) depressed all behaviour. Ketoprofen (1.0 mg/kg) blocked both acid-induced stimulation of stretching and depression of ICSS without altering control ICSS. CONCLUSION These results support further consideration of NMDA receptor antagonists as analgesics; however, some NMDA receptor antagonists are more efficacious at attenuating pain-depressed behaviours. WHAT DOES THIS STUDY ADD NMDA receptor antagonists produce dissociable effects on pain-depressed behaviour. Provides evidence that pain-depressed behaviours should be considered and evaluated when determining the antinociceptive effects of NMDA receptor antagonists.
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Affiliation(s)
- T M Hillhouse
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA.,Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA
| | - S S Negus
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA
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Freitas KC, Carroll FI, Negus SS. Effects of nicotinic acetylcholine receptor agonists in assays of acute pain-stimulated and pain-depressed behaviors in rats. J Pharmacol Exp Ther 2016; 355:341-50. [PMID: 26359313 DOI: 10.1124/jpet.115.226803] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Agonists at nicotinic acetylcholine receptors (nAChRs) constitute one drug class being evaluated as candidate analgesics. Previous preclinical studies have implicated α4β2 and α7 nAChRs as potential mediators of the antinociceptive effects of (–)-nicotine hydrogen tartrate (nicotine) and other nAChR agonists; however, these studies have relied exclusively on measures of pain-stimulated behavior, which can be defined as behaviors that increase in frequency, rate, or intensity after presentation of a noxious stimulus. Pain is also associated with depression of many behaviors, and drug effects can differ in assays of pain-stimulated versus pain-depressed behavior. Accordingly, this study compared the effects of nicotine, the selective α4/6β2 agonist 5-(123I)iodo-3-[2(S)-2-azetidinylmethoxy]pyridine (5-I-A-85380), and the selective α7 agonist N-(3R)-1-azabicyclo(2.2.2)oct-3-yl-4-chlorobenzamide in assays of pain-stimulated and pain-depressed behavior in male Sprague-Dawley rats. Intraperitoneal injection of dilute lactic acid served as an acute noxious stimulus to either stimulate a stretching response or depress the operant responding, which is maintained by electrical brain stimulation in an intracranial self-stimulation (ICSS) procedure. Nicotine produced a dose-dependent, time-dependent, and mecamylamine-reversible blockade of both acid-stimulated stretching and acid-induced depression of ICSS. 5-I-A-85380 also blocked both acid-stimulated stretching and acid-induced depression of ICSS, whereas N-(3R)-1-azabicyclo(2.2.2)oct-3-yl-4-chlorobenzamide produced no effect in either procedure. Both nicotine and 5-I-A-85380 were ≥10-fold more potent in blocking the acid-induced depression of ICSS than in blocking the acid-induced stimulation of stretching. These results suggest that stimulation of α4β2 and/or α6β2 nAChRs may be especially effective to alleviate the signs of pain-related behavioral depression in rats; however, nonselective behavioral effects may contribute to apparent antinociception.
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Affiliation(s)
- Kelen C Freitas
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
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Hernandez G, Cheer JF. To Act or Not to Act: Endocannabinoid/Dopamine Interactions in Decision-Making. Front Behav Neurosci 2015; 9:336. [PMID: 26733830 PMCID: PMC4681836 DOI: 10.3389/fnbeh.2015.00336] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 11/19/2015] [Indexed: 12/11/2022] Open
Abstract
Decision-making is an ethologically adaptive construct that is impaired in multiple psychiatric disorders. Activity within the mesocorticolimbic dopamine system has been traditionally associated with decision-making. The endocannabinoid system through its actions on inhibitory and excitatory synapses modulates dopamine activity and decision-making. The aim of this brief review is to present a synopsis of available data obtained when the endocannabinoid system is manipulated and dopamine activity recorded. To this end, we review research using different behavioral paradigms to provide further insight into how this ubiquitous signaling system biases dopamine-related behaviors to regulate decision-making.
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Affiliation(s)
- Giovanni Hernandez
- Faculté de Pharmacie, Université de Montréal Montréal, Quebec, QC, Canada
| | - Joseph F Cheer
- Department of Anatomy and Neurobiology, University of Maryland School of MedicineBaltimore, Maryland, MD, USA; Department of Psychiatry, University of Maryland School of MedicineBaltimore, Maryland, MD, USA
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Marco EM, Rapino C, Caprioli A, Borsini F, Laviola G, Maccarrone M. Potential Therapeutic Value of a Novel FAAH Inhibitor for the Treatment of Anxiety. PLoS One 2015; 10:e0137034. [PMID: 26360704 PMCID: PMC4567375 DOI: 10.1371/journal.pone.0137034] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 08/11/2015] [Indexed: 11/21/2022] Open
Abstract
Anxiety disorders are among the most prevalent psychiatric diseases with high personal costs and a remarkable socio-economic burden. However, current treatment of anxiety is far from satisfactory. Novel pharmacological targets have emerged in the recent years, and attention has focused on the endocannabinoid (eCB) system, given the increasing evidence that supports its central role in emotion, coping with stress and anxiety. In the management of anxiety disorders, drug development strategies have left apart the direct activation of type-1 cannabinoid receptors to indirectly enhance eCB signalling through the inhibition of eCB deactivation, that is, the inhibition of the fatty acid amide hydrolase (FAAH) enzyme. In the present study, we provide evidence for the anxiolytic-like properties of a novel, potent and selective reversible inhibitor of FAAH, ST4070, orally administered to rodents. ST4070 (3 to 30 mg/kg per os) administered to CD1 male mice induced an increase of time spent in the exploration of the open arms of the elevated-plus maze. A partial reduction of anxiety-related behaviour by ST4070 was also obtained in Wistar male rats, which moderately intensified the time spent in the illuminated compartment of the light-dark box. ST4070 clearly inhibited FAAH activity and augmented the levels of two of its substrates, N-arachidonoylethanolamine (anandamide) and N-palmitoylethanolamine, in anxiety-relevant brain regions. Altogether, ST4070 offers a promising anxiolytic-like profile in preclinical studies, although further studies are warranted to clearly demonstrate its efficacy in the clinic management of anxiety disorders.
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Affiliation(s)
- Eva M. Marco
- Section of Behavioural Neuroscience, Dept. Cell Biology and Neurosciences, Istituto Superiore di Sanità, Rome, Italy
| | - Cinzia Rapino
- Dept. Biomedical Sciences, Università degli Studi di Teramo, Teramo, Italy
| | | | | | - Giovanni Laviola
- Section of Behavioural Neuroscience, Dept. Cell Biology and Neurosciences, Istituto Superiore di Sanità, Rome, Italy
- * E-mail: (GL); (MM)
| | - Mauro Maccarrone
- School of Medicine, Campus Bio-Medico University of Rome, Rome, Italy
- Centro Europeo di Ricerca sul Cervello (CERC)/IRCCS Fondazione Santa Lucia, Rome, Italy
- * E-mail: (GL); (MM)
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Fitzgibbon M, Finn DP, Roche M. High Times for Painful Blues: The Endocannabinoid System in Pain-Depression Comorbidity. Int J Neuropsychopharmacol 2015; 19:pyv095. [PMID: 26342110 PMCID: PMC4815466 DOI: 10.1093/ijnp/pyv095] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 08/17/2015] [Indexed: 01/06/2023] Open
Abstract
Depression and pain are two of the most debilitating disorders worldwide and have an estimated cooccurrence of up to 80%. Comorbidity of these disorders is more difficult to treat, associated with significant disability and impaired health-related quality of life than either condition alone, resulting in enormous social and economic cost. Several neural substrates have been identified as potential mediators in the association between depression and pain, including neuroanatomical reorganization, monoamine and neurotrophin depletion, dysregulation of the hypothalamo-pituitary-adrenal axis, and neuroinflammation. However, the past decade has seen mounting evidence supporting a role for the endogenous cannabinoid (endocannabinoid) system in affective and nociceptive processing, and thus, alterations in this system may play a key role in reciprocal interactions between depression and pain. This review will provide an overview of the preclinical evidence supporting an interaction between depression and pain and the evidence supporting a role for the endocannabinoid system in this interaction.
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Affiliation(s)
| | | | - Michelle Roche
- Physiology (Ms Fitzgibbon and Dr Roche), and Pharmacology and Therapeutics (Dr Finn), School of Medicine, Galway Neuroscience Centre and Centre for Pain Research (Ms Fitzgibbon, Dr Finn, and Dr Roche), National Centre for Biomedical Engineering Science, National University of Ireland Galway, Ireland.
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Corcoran L, Roche M, Finn DP. The Role of the Brain's Endocannabinoid System in Pain and Its Modulation by Stress. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2015; 125:203-55. [DOI: 10.1016/bs.irn.2015.10.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Gamage TF, Ignatowska-Jankowska BM, Muldoon PP, Cravatt BF, Damaj MI, Lichtman AH. Differential effects of endocannabinoid catabolic inhibitors on morphine withdrawal in mice. Drug Alcohol Depend 2015; 146:7-16. [PMID: 25479915 PMCID: PMC4295928 DOI: 10.1016/j.drugalcdep.2014.11.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 11/16/2014] [Accepted: 11/16/2014] [Indexed: 02/07/2023]
Abstract
BACKGROUND Inhibition of endocannabinoid catabolic enzymes fatty acid amide hydrolase (FAAH) and/or monoacylglycerol lipase (MAGL) reduces somatic morphine withdrawal signs, but its effects on aversive aspects of withdrawal are unknown. The present study investigated whether Δ(9)-tetrahydrocannabinol (THC), the MAGL inhibitor JZL184, the FAAH inhibitor PF-3845, or the dual FAAH/MAGL inhibitor SA-57 would reduce acquisition of morphine withdrawal-induced conditioned place avoidance (CPA) and jumping. METHODS Mice were implanted with placebo or 75 mg morphine pellets, 48 h later injected with naloxone or saline and placed in the conditioning apparatus, and assessed for CPA at 72 h. Subjects were also observed for jumping behavior following naloxone challenge. RESULTS Naloxone (0.056 mg/kg) produced robust CPA in morphine-pelleted, but not placebo-pelleted, mice. Morphine pretreatment prevented the occurrence of withdrawal CPA and withdrawal jumping, while clonidine (an α2 adrenergic receptor agonist) only blocked withdrawal CPA. THC, JZL184, and SA-57 significantly reduced the percentage of mice that jumped during the conditioning session, but did not affect acquisition of withdrawal CPA. PF-3845 did not reduce morphine withdrawal CPA or jumping. Finally, neither THC nor the endocannabinoid catabolic enzyme inhibitors in non-dependent mice elicited a conditioned place preference or aversion. CONCLUSIONS These findings suggest that inhibiting endocannabinoid catabolic enzymes reduces somatic morphine withdrawal signs, but not aversive aspects as inferred in the CPA paradigm. The observation that non-dependent mice administered inhibitors of endocannabinoid degradation did not display place preferences is consistent with the idea that that endocannabinoid catabolic enzymes might be targeted therapeutically, with reduced risk of abuse.
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Affiliation(s)
- Thomas F. Gamage
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Kontos Medical Sciences Building, 1217 East Marshall Street, Richmond, VA, 23298
| | - Bogna M. Ignatowska-Jankowska
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Kontos Medical Sciences Building, 1217 East Marshall Street, Richmond, VA, 23298
| | - Pretal P. Muldoon
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Kontos Medical Sciences Building, 1217 East Marshall Street, Richmond, VA, 23298
| | - Benjamin F. Cravatt
- The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, 10550 N. Torrey Pines Rd. La Jolla, CA 92037
| | - M. Imad Damaj
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Kontos Medical Sciences Building, 1217 East Marshall Street, Richmond, VA, 23298
| | - Aron H. Lichtman
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Kontos Medical Sciences Building, 1217 East Marshall Street, Richmond, VA, 23298
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The Potential of Inhibitors of Endocannabinoid Metabolism for Drug Development: A Critical Review. Handb Exp Pharmacol 2015; 231:95-128. [PMID: 26408159 DOI: 10.1007/978-3-319-20825-1_4] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The endocannabinoids anandamide and 2-arachidonoylglycerol are metabolised by both hydrolytic enzymes (primarily fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MGL)) and oxygenating enzymes (e.g. cyclooxygenase-2, COX-2). In the present article, the in vivo data for compounds inhibiting endocannabinoid metabolism have been reviewed, focussing on inflammation and pain. Potential reasons for the failure of an FAAH inhibitor in a clinical trial in patients with osteoarthritic pain are discussed. It is concluded that there is a continued potential for compounds inhibiting endocannabinoid metabolism in terms of drug development, but that it is wise not to be unrealistic in terms of expectations of success.
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Wiebelhaus JM, Grim TW, Owens RA, Lazenka MF, Sim-Selley LJ, Abdullah RA, Niphakis MJ, Vann RE, Cravatt BF, Wiley JL, Negus SS, Lichtman AH. Δ9-tetrahydrocannabinol and endocannabinoid degradative enzyme inhibitors attenuate intracranial self-stimulation in mice. J Pharmacol Exp Ther 2014; 352:195-207. [PMID: 25398241 DOI: 10.1124/jpet.114.218677] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A growing body of evidence implicates endogenous cannabinoids as modulators of the mesolimbic dopamine system and motivated behavior. Paradoxically, the reinforcing effects of Δ(9)-tetrahydrocannabinol (THC), the primary psychoactive constituent of cannabis, have been difficult to detect in preclinical rodent models. In this study, we investigated the impact of THC and inhibitors of the endocannabinoid hydrolytic enzymes fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL) on operant responding for electrical stimulation of the medial forebrain bundle [intracranial self-stimulation (ICSS)], which is known to activate the mesolimbic dopamine system. These drugs were also tested in assays of operant responding for food reinforcement and spontaneous locomotor activity. THC and the MAGL inhibitor JZL184 (4-[bis(1,3-benzodioxol-5-yl)hydroxymethyl]-1-piperidinecarboxylic acid 4-nitrophenyl ester) attenuated operant responding for ICSS and food, and also reduced spontaneous locomotor activity. In contrast, the FAAH inhibitor PF-3845 (N-3-pyridinyl-4-[[3-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenyl]methyl]-1-piperidinecarboxamide) was largely without effect in these assays. Consistent with previous studies showing that combined inhibition of FAAH and MAGL produces a substantially greater cannabimimetic profile than single enzyme inhibition, the dual FAAH-MAGL inhibitor SA-57 (4-[2-(4-chlorophenyl)ethyl]-1-piperidinecarboxylic acid 2-(methylamino)-2-oxoethyl ester) produced a similar magnitude of ICSS depression as that produced by THC. ICSS attenuation by JZL184 was associated with increased brain levels of 2-arachidonoylglycerol (2-AG), whereas peak effects of SA-57 were associated with increased levels of both N-arachidonoylethanolamine (anandamide) and 2-AG. The cannabinoid receptor type 1 receptor antagonist rimonabant, but not the cannabinoid receptor type 2 receptor antagonist SR144528, blocked the attenuating effects of THC, JZL184, and SA-57 on ICSS. Thus, THC, MAGL inhibition, and dual FAAH-MAGL inhibition not only reduce ICSS, but also decrease other reinforced and nonreinforced behaviors.
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Affiliation(s)
- Jason M Wiebelhaus
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, Virginia (J.M.W., T.W.G., R.A.O., M.F.L., L.J.S.-S., R.A.A., R.E.V., S.S.N., A.H.L.); Skaggs Institute for Chemical Biology and Department of Chemical Physiology, Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and RTI International, Research Triangle Park, North Carolina (J.L.W.)
| | - Travis W Grim
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, Virginia (J.M.W., T.W.G., R.A.O., M.F.L., L.J.S.-S., R.A.A., R.E.V., S.S.N., A.H.L.); Skaggs Institute for Chemical Biology and Department of Chemical Physiology, Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and RTI International, Research Triangle Park, North Carolina (J.L.W.)
| | - Robert A Owens
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, Virginia (J.M.W., T.W.G., R.A.O., M.F.L., L.J.S.-S., R.A.A., R.E.V., S.S.N., A.H.L.); Skaggs Institute for Chemical Biology and Department of Chemical Physiology, Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and RTI International, Research Triangle Park, North Carolina (J.L.W.)
| | - Matthew F Lazenka
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, Virginia (J.M.W., T.W.G., R.A.O., M.F.L., L.J.S.-S., R.A.A., R.E.V., S.S.N., A.H.L.); Skaggs Institute for Chemical Biology and Department of Chemical Physiology, Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and RTI International, Research Triangle Park, North Carolina (J.L.W.)
| | - Laura J Sim-Selley
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, Virginia (J.M.W., T.W.G., R.A.O., M.F.L., L.J.S.-S., R.A.A., R.E.V., S.S.N., A.H.L.); Skaggs Institute for Chemical Biology and Department of Chemical Physiology, Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and RTI International, Research Triangle Park, North Carolina (J.L.W.)
| | - Rehab A Abdullah
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, Virginia (J.M.W., T.W.G., R.A.O., M.F.L., L.J.S.-S., R.A.A., R.E.V., S.S.N., A.H.L.); Skaggs Institute for Chemical Biology and Department of Chemical Physiology, Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and RTI International, Research Triangle Park, North Carolina (J.L.W.)
| | - Micah J Niphakis
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, Virginia (J.M.W., T.W.G., R.A.O., M.F.L., L.J.S.-S., R.A.A., R.E.V., S.S.N., A.H.L.); Skaggs Institute for Chemical Biology and Department of Chemical Physiology, Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and RTI International, Research Triangle Park, North Carolina (J.L.W.)
| | - Robert E Vann
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, Virginia (J.M.W., T.W.G., R.A.O., M.F.L., L.J.S.-S., R.A.A., R.E.V., S.S.N., A.H.L.); Skaggs Institute for Chemical Biology and Department of Chemical Physiology, Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and RTI International, Research Triangle Park, North Carolina (J.L.W.)
| | - Benjamin F Cravatt
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, Virginia (J.M.W., T.W.G., R.A.O., M.F.L., L.J.S.-S., R.A.A., R.E.V., S.S.N., A.H.L.); Skaggs Institute for Chemical Biology and Department of Chemical Physiology, Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and RTI International, Research Triangle Park, North Carolina (J.L.W.)
| | - Jenny L Wiley
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, Virginia (J.M.W., T.W.G., R.A.O., M.F.L., L.J.S.-S., R.A.A., R.E.V., S.S.N., A.H.L.); Skaggs Institute for Chemical Biology and Department of Chemical Physiology, Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and RTI International, Research Triangle Park, North Carolina (J.L.W.)
| | - S Stevens Negus
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, Virginia (J.M.W., T.W.G., R.A.O., M.F.L., L.J.S.-S., R.A.A., R.E.V., S.S.N., A.H.L.); Skaggs Institute for Chemical Biology and Department of Chemical Physiology, Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and RTI International, Research Triangle Park, North Carolina (J.L.W.)
| | - Aron H Lichtman
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, Virginia (J.M.W., T.W.G., R.A.O., M.F.L., L.J.S.-S., R.A.A., R.E.V., S.S.N., A.H.L.); Skaggs Institute for Chemical Biology and Department of Chemical Physiology, Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and RTI International, Research Triangle Park, North Carolina (J.L.W.)
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Abstract
Intracranial self-stimulation (ICSS) is a behavioral procedure in which operant responding is maintained by pulses of electrical brain stimulation. In research to study abuse-related drug effects, ICSS relies on electrode placements that target the medial forebrain bundle at the level of the lateral hypothalamus, and experimental sessions manipulate frequency or amplitude of stimulation to engender a wide range of baseline response rates or response probabilities. Under these conditions, drug-induced increases in low rates/probabilities of responding maintained by low frequencies/amplitudes of stimulation are interpreted as an abuse-related effect. Conversely, drug-induced decreases in high rates/probabilities of responding maintained by high frequencies/amplitudes of stimulation can be interpreted as an abuse-limiting effect. Overall abuse potential can be inferred from the relative expression of abuse-related and abuse-limiting effects. The sensitivity and selectivity of ICSS to detect abuse potential of many classes of abused drugs is similar to the sensitivity and selectivity of drug self-administration procedures. Moreover, similar to progressive-ratio drug self-administration procedures, ICSS data can be used to rank the relative abuse potential of different drugs. Strengths of ICSS in comparison with drug self-administration include 1) potential for simultaneous evaluation of both abuse-related and abuse-limiting effects, 2) flexibility for use with various routes of drug administration or drug vehicles, 3) utility for studies in drug-naive subjects as well as in subjects with controlled levels of prior drug exposure, and 4) utility for studies of drug time course. Taken together, these considerations suggest that ICSS can make significant contributions to the practice of abuse potential testing.
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Affiliation(s)
- S Stevens Negus
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Laurence L Miller
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
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Panagis G, Mackey B, Vlachou S. Cannabinoid Regulation of Brain Reward Processing with an Emphasis on the Role of CB1 Receptors: A Step Back into the Future. Front Psychiatry 2014; 5:92. [PMID: 25132823 PMCID: PMC4117180 DOI: 10.3389/fpsyt.2014.00092] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 07/16/2014] [Indexed: 01/17/2023] Open
Abstract
Over the last decades, the endocannabinoid system has been implicated in a large variety of functions, including a crucial modulation of brain-reward circuits and the regulation of motivational processes. Importantly, behavioral studies have shown that cannabinoid compounds activate brain reward mechanisms and circuits in a similar manner to other drugs of abuse, such as nicotine, alcohol, cocaine, and heroin, although the conditions under which cannabinoids exert their rewarding effects may be more limited. Furthermore, there is evidence on the involvement of the endocannabinoid system in the regulation of cue- and drug-induced relapsing phenomena in animal models. The aim of this review is to briefly present the available data obtained using diverse behavioral experimental approaches in experimental animals, namely, the intracranial self-stimulation paradigm, the self-administration procedure, the conditioned place preference procedure, and the reinstatement of drug-seeking behavior procedure, to provide a comprehensive picture of the current status of what is known about the endocannabinoid system mechanisms that underlie modification of brain-reward processes. Emphasis is placed on the effects of cannabinoid 1 (CB1) receptor agonists, antagonists, and endocannabinoid modulators. Further, the role of CB1 receptors in reward processes is investigated through presentation of respective genetic ablation studies in mice. The vast majority of studies in the existing literature suggest that the endocannabinoid system plays a major role in modulating motivation and reward processes. However, much remains to be done before we fully understand these interactions. Further research in the future will shed more light on these processes and, thus, could lead to the development of potential pharmacotherapies designed to treat reward-dysfunction-related disorders.
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Affiliation(s)
- George Panagis
- Laboratory of Behavioral Neuroscience, Department of Psychology, School of Social Sciences, University of Crete , Rethymno , Greece
| | - Brian Mackey
- Laboratory of Behavioural Neuroscience, School of Nursing and Human Sciences, Faculty of Science and Health, Dublin City University , Dublin , Ireland
| | - Styliani Vlachou
- Laboratory of Behavioural Neuroscience, School of Nursing and Human Sciences, Faculty of Science and Health, Dublin City University , Dublin , Ireland
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