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Nocheva H, Stoynev N, Vodenicharov V, Krastev D, Krastev N, Mileva M. Cannabinoid and Serotonergic Systems: Unraveling the Pathogenetic Mechanisms of Stress-Induced Analgesia. Biomedicines 2024; 12:235. [PMID: 38275406 PMCID: PMC10813752 DOI: 10.3390/biomedicines12010235] [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: 11/07/2023] [Revised: 01/12/2024] [Accepted: 01/12/2024] [Indexed: 01/27/2024] Open
Abstract
The perception of "stress" triggers many physiological and behavioral responses, collectively called the stress response. Such a complex process allows for coping with stress and also triggers severe pathology. Because of the multidirectional effect of stress on the body, multiple systems participate in its pathogenesis, with the endogenous cannabinoid and the serotoninergic ones among them. These two systems also take part in the pain perception decrease, known as stress-induced analgesia (SIA), which can then be taken as an indirect indicator of the stress response. The aim of our study was to study the changes in cold SIA (c-SIA) resulting from the exogenous activation of cannabinoid receptor type 1 (CB1) and 5-hydroxytryptamine (5-HT, serotonin) receptor type 1A (5-HT1A). Various combinations of agonists and/or antagonists of CB1 and 5-HT1A, before or after 1 h of cold exposure, were applied, since we presumed that the exogenous activation of the receptors before the cold exposure would influence the pathogenesis of the stress response, while their activation after the stressful trigger would influence the later development. Our results show that the serotonergic system "maintained" c-SIA in the pre-stress treatment, while the cannabinoids' modulative effect was more prominent in the post-stress treatment. Here, we show the interactions of the two systems in the stress response. The interpretation and understanding of the mechanisms of interaction between CB1 and 5-HT1A may provide information for the prevention and control of adverse stress effects, as well as suggest interesting directions for the development of targeted interventions for the control of specific body responses.
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Affiliation(s)
- Hristina Nocheva
- Department of Physiology and Pathophysiology, Medical Faculty, Medical University, 2 Zdrave Str., 1431 Sofia, Bulgaria; (H.N.); (N.S.)
| | - Nikolay Stoynev
- Department of Physiology and Pathophysiology, Medical Faculty, Medical University, 2 Zdrave Str., 1431 Sofia, Bulgaria; (H.N.); (N.S.)
| | - Vlayko Vodenicharov
- Department of Epidemiology and Hygiene, Medical Faculty, Medical University, 2 Zdrave Str., 1431 Sofia, Bulgaria;
| | - Dimo Krastev
- Department of Anatomy and Physiology, South-West University “Neofit Rilski”, Blagoevgrad, 66, Ivan Mihaylov Str., 2700 Blagoevgrad, Bulgaria;
| | - Nikolay Krastev
- Department of Anatomy, Faculty of Medicine, Medical University, 2, Zdrave Str., 1431 Sofia, Bulgaria;
| | - Milka Mileva
- Institute of Microbiology “Stephan Angeloff”, Bulgarian Academy of Sciences, 26, Acad. Georgi Bonchev Str., 1113 Sofia, Bulgaria
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Scott C, Hall S, Zhou J, Lehmann C. Cannabinoids and the Endocannabinoid System in Early SARS-CoV-2 Infection and Long COVID-19-A Scoping Review. J Clin Med 2023; 13:227. [PMID: 38202234 PMCID: PMC10779964 DOI: 10.3390/jcm13010227] [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: 11/17/2023] [Revised: 12/21/2023] [Accepted: 12/27/2023] [Indexed: 01/12/2024] Open
Abstract
Coronavirus disease-19 (COVID-19) is a highly contagious illness caused by the SARS-CoV-2 virus. The clinical presentation of COVID-19 is variable, often including symptoms such as fever, cough, headache, fatigue, and an altered sense of smell and taste. Recently, post-acute "long" COVID-19 has emerged as a concern, with symptoms persisting beyond the acute infection. Vaccinations remain one of the most effective preventative methods against severe COVID-19 outcomes and the development of long-term COVID-19. However, individuals with underlying health conditions may not mount an adequate protective response to COVID-19 vaccines, increasing the likelihood of severe symptoms, hospitalization, and the development of long-term COVID-19 in high-risk populations. This review explores the potential therapeutic role of cannabinoids in limiting the susceptibility and severity of infection, both pre- and post-SARS-CoV-19 infection. Early in the SARS-CoV-19 infection, cannabinoids have been shown to prevent viral entry, mitigate oxidative stress, and alleviate the associated cytokine storm. Post-SARS-CoV-2 infection, cannabinoids have shown promise in treating symptoms associated with post-acute long COVID-19, including depression, anxiety, post-traumatic stress injury, insomnia, pain, and decreased appetite. While current research primarily focuses on potential treatments for the acute phase of COVID-19, there is a gap in research addressing therapeutics for the early and post-infectious phases. This review highlights the potential for future research to bridge this gap by investigating cannabinoids and the endocannabinoid system as a potential treatment strategy for both early and post-SARS-CoV-19 infection.
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Affiliation(s)
- Cassidy Scott
- Department of Anesthesia, Pain Management and Perioperative Medicine, Dalhousie University, Halifax, NS B3H 1X5, Canada; (C.S.); (J.Z.)
| | - Stefan Hall
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NS B3H 1X5, Canada;
| | - Juan Zhou
- Department of Anesthesia, Pain Management and Perioperative Medicine, Dalhousie University, Halifax, NS B3H 1X5, Canada; (C.S.); (J.Z.)
| | - Christian Lehmann
- Department of Anesthesia, Pain Management and Perioperative Medicine, Dalhousie University, Halifax, NS B3H 1X5, Canada; (C.S.); (J.Z.)
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NS B3H 1X5, Canada;
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Pagliusi M, Gomes FV. The Role of The Rostral Ventromedial Medulla in Stress Responses. Brain Sci 2023; 13:brainsci13050776. [PMID: 37239248 DOI: 10.3390/brainsci13050776] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/30/2023] [Accepted: 05/05/2023] [Indexed: 05/28/2023] Open
Abstract
The rostral ventromedial medulla (RVM) is a brainstem structure critical for the descending pain modulation system involved in both pain facilitation and inhibition through its projection to the spinal cord. Since the RVM is well connected with pain- and stress-engaged brain structures, such as the anterior cingulate cortex, nucleus accumbens, and amygdala, its involvement in stress responses has become a matter of great interest. While chronic stress has been proposed as a trigger of pain chronification and related psychiatric comorbidities due to maladaptive stress responses, acute stress triggers analgesia and other adaptative responses. Here we reviewed and highlighted the critical role of the RVM in stress responses, mainly in acute stress-induced analgesia (SIA) and chronic stress-induced hyperalgesia (SIH), providing insights into pain chronification processes and comorbidity between chronic pain and psychiatric disorders.
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Affiliation(s)
- Marco Pagliusi
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14015-069, SP, Brazil
| | - Felipe V Gomes
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14015-069, SP, Brazil
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Blanton H, Reddy PH, Benamar K. Chronic pain in Alzheimer's disease: Endocannabinoid system. Exp Neurol 2023; 360:114287. [PMID: 36455638 PMCID: PMC9789196 DOI: 10.1016/j.expneurol.2022.114287] [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: 08/08/2022] [Revised: 11/09/2022] [Accepted: 11/23/2022] [Indexed: 11/30/2022]
Abstract
Chronic pain, one of the most common reasons adults seek medical care, has been linked to restrictions in mobility and daily activities, dependence on opioids, anxiety, depression, sleep deprivation, and reduced quality of life. Alzheimer's disease (AD), a devastating neurodegenerative disorder (characterized by a progressive impairment of cognitive functions) in the elderly, is often co-morbid with chronic pain. AD is one of the most common neurodegenerative disorders in the aged population. The reported prevalence of chronic pain is 45.8% of the 50 million people with AD. As the population ages, the number of older people who experience AD and chronic pain will also increase. The current treatment options for chronic pain are limited, often ineffective, and have associated side effects. This review summarizes the role of the endocannabinoid system in pain, its potential role in chronic pain in AD, and addresses gaps and future directions.
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Affiliation(s)
- Henry Blanton
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, School of Medicine, Lubbock, TX 79430, USA
| | - P Hemachandra Reddy
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, School of Medicine, Lubbock, TX 79430, USA; Internal Medicine Department, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX 79430, USA
| | - Khalid Benamar
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, School of Medicine, Lubbock, TX 79430, USA.
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Chia JSM, Farouk AAO, Mohamad TAST, Sulaiman MR, Zakaria H, Hassan NI, Perimal EK. Zerumbone Ameliorates Neuropathic Pain Symptoms via Cannabinoid and PPAR Receptors Using In Vivo and In Silico Models. Molecules 2021; 26:3849. [PMID: 34202590 PMCID: PMC8270339 DOI: 10.3390/molecules26133849] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/17/2021] [Accepted: 05/25/2021] [Indexed: 01/14/2023] Open
Abstract
Neuropathic pain is a chronic pain condition persisting past the presence of any noxious stimulus or inflammation. Zerumbone, of the Zingiber zerumbet ginger plant, has exhibited anti-allodynic and antihyperalgesic effects in a neuropathic pain animal model, amongst other pharmacological properties. This study was conducted to further elucidate the mechanisms underlying zerumbone's antineuropathic actions. Research on therapeutic agents involving cannabinoid (CB) and peroxisome proliferator-activated receptors (PPARs) is rising. These receptor systems have shown importance in causing a synergistic effect in suppressing nociceptive processing. Behavioural responses were assessed using the von Frey filament test (mechanical allodynia) and Hargreaves plantar test (thermal hyperalgesia), in chronic constriction injury (CCI) neuropathic pain mice. Antagonists SR141716 (CB1 receptor), SR144528 (CB2 receptor), GW6471 (PPARα receptor) and GW9662 (PPARγ receptor) were pre-administered before the zerumbone treatment. Our findings indicated the involvement of CB1, PPARα and PPARγ in zerumbone's action against mechanical allodynia, whereas only CB1 and PPARα were involved against thermal hyperalgesia. Molecular docking studies also suggest that zerumbone has a comparable and favourable binding affinity against the respective agonist on the CB and PPAR receptors studied. This finding will contribute to advance our knowledge on zerumbone and its significance in treating neuropathic pain.
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MESH Headings
- Animals
- Disease Models, Animal
- Male
- Mice
- Mice, Inbred ICR
- Neuralgia/drug therapy
- Neuralgia/metabolism
- Neuralgia/pathology
- PPAR alpha/antagonists & inhibitors
- PPAR alpha/metabolism
- PPAR gamma/antagonists & inhibitors
- PPAR gamma/metabolism
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB2/antagonists & inhibitors
- Receptor, Cannabinoid, CB2/metabolism
- Sesquiterpenes/pharmacology
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Affiliation(s)
- Jasmine Siew Min Chia
- Centre for Community Health Studies (ReaCH), Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur 50300, Malaysia;
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia; (A.A.O.F.); (T.A.S.T.M.); (M.R.S.)
| | - Ahmad Akira Omar Farouk
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia; (A.A.O.F.); (T.A.S.T.M.); (M.R.S.)
| | - Tengku Azam Shah Tengku Mohamad
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia; (A.A.O.F.); (T.A.S.T.M.); (M.R.S.)
| | - Mohd Roslan Sulaiman
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia; (A.A.O.F.); (T.A.S.T.M.); (M.R.S.)
| | - Hanis Zakaria
- Department of Chemical Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Malaysia; (H.Z.); (N.I.H.)
| | - Nurul Izzaty Hassan
- Department of Chemical Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Malaysia; (H.Z.); (N.I.H.)
| | - Enoch Kumar Perimal
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia; (A.A.O.F.); (T.A.S.T.M.); (M.R.S.)
- Australian Research Council Centre of Excellence for Nanoscale BioPhotonics, University of Adelaide, Adelaide, South Australia 5005, Australia
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6
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Blanton HL, Barnes RC, McHann MC, Bilbrey JA, Wilkerson JL, Guindon J. Sex differences and the endocannabinoid system in pain. Pharmacol Biochem Behav 2021; 202:173107. [PMID: 33444598 DOI: 10.1016/j.pbb.2021.173107] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 11/30/2020] [Accepted: 12/30/2020] [Indexed: 01/21/2023]
Abstract
Cannabis use has been increasing in recent years, particularly among women, and one of the most common uses of cannabis for medical purposes is pain relief. Pain conditions and response to analgesics have been demonstrated to be influenced by sex, and evidence is emerging that this is also true with cannabinoid-mediated analgesia. In this review we evaluate the preclinical evidence supporting sex differences in cannabinoid pharmacology, as well as emerging evidence from human studies, both clinical and observational. Numerous animal studies have reported sex differences in the antinociceptive response to natural and synthetic cannabinoids that may correlate to sex differences in expression, and function, of endocannabinoid system components. Female rodents have generally been found to be more sensitive to the effects of Δ9-THC. This finding is likely a function of both pharmacokinetic and pharmacodynamics factors including differences in metabolism, differences in cannabinoid receptor expression, and influence of ovarian hormones including estradiol and progesterone. Preclinical evidence supporting direct interactions between sex hormones and the endocannabinoid system may translate to sex differences in response to cannabis and cannabinoid use in men and women. Further research into the role of sex in endocannabinoid system function is critical as we gain a deeper understanding of the impact of the endocannabinoid system in various disease states, including chronic pain.
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Affiliation(s)
- Henry L Blanton
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430, United States of America.
| | - Robert C Barnes
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430, United States of America
| | - Melissa C McHann
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430, United States of America
| | - Joshua A Bilbrey
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL 32611, United States of America
| | - Jenny L Wilkerson
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL 32611, United States of America
| | - Josée Guindon
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430, United States of America.
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7
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Alkislar I, Miller AR, Hohmann AG, Sadaka AH, Cai X, Kulkarni P, Ferris CF. Inhaled Cannabis Suppresses Chemotherapy-Induced Neuropathic Nociception by Decoupling the Raphe Nucleus: A Functional Imaging Study in Rats. BIOLOGICAL PSYCHIATRY: COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2020; 6:479-489. [PMID: 33622657 DOI: 10.1016/j.bpsc.2020.11.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/30/2020] [Accepted: 11/22/2020] [Indexed: 12/18/2022]
Abstract
BACKGROUND Efficacy of inhaled cannabis for treating pain is controversial. Effective treatment for chemotherapy-induced neuropathy represents an unmet medical need. We hypothesized that cannabis reduces neuropathic pain by reducing functional coupling in the raphe nuclei. METHODS We assessed the impact of inhalation of vaporized cannabis plant (containing 10.3% Δ9-tetrahydrocannabinol/0.05% cannabidiol) or placebo cannabis on brain resting-state blood oxygen level-dependent functional connectivity and pain behavior induced by paclitaxel in rats. Rats received paclitaxel to produce chemotherapy-induced peripheral neuropathy or its vehicle. Behavioral and imaging experiments were performed after neuropathy was established and stable. Images were registered to, and analyzed using, a 3D magnetic resonance imaging rat atlas providing site-specific data on more than 168 different brain areas. RESULTS Prior to vaporization, paclitaxel produced cold allodynia. Inhaled vaporized cannabis increased cold withdrawal latencies relative to prevaporization or placebo cannabis, consistent with Δ9-tetrahydrocannabinol-induced antinociception. In paclitaxel-treated rats, the midbrain serotonergic system, comprising the dorsal and median raphe, showed hyperconnectivity to cortical, brainstem, and hippocampal areas, consistent with nociceptive processing. Inhalation of vaporized cannabis uncoupled paclitaxel-induced hyperconnectivity patterns. No such changes in connectivity or cold responsiveness were observed following placebo cannabis vaporization. CONCLUSIONS Inhaled vaporized cannabis plant uncoupled brain resting-state connectivity in the raphe nuclei, normalizing paclitaxel-induced hyperconnectivity to levels observed in vehicle-treated rats. Inhaled vaporized cannabis produced antinociception in both paclitaxel- and vehicle-treated rats. Our study elucidates neural circuitry implicated in the therapeutic effects of Δ9-tetrahydrocannabinol and supports a role for functional imaging studies in animals in guiding indications for future clinical trials.
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Affiliation(s)
- Ilayda Alkislar
- Center for Translational Neuroimaging, Northeastern University, Boston, Massachusetts
| | - Alison R Miller
- Center for Translational Neuroimaging, Northeastern University, Boston, Massachusetts
| | - Andrea G Hohmann
- Psychological and Brain Sciences, Program in Neuroscience, and Gill Center for Biomolecular Science, Indiana University, Bloomington, Indiana
| | - Aymen H Sadaka
- Center for Translational Neuroimaging, Northeastern University, Boston, Massachusetts
| | - Xuezhu Cai
- Center for Translational Neuroimaging, Northeastern University, Boston, Massachusetts
| | - Praveen Kulkarni
- Center for Translational Neuroimaging, Northeastern University, Boston, Massachusetts
| | - Craig F Ferris
- Center for Translational Neuroimaging, Northeastern University, Boston, Massachusetts; Department of Psychology, Northeastern University, Boston, Massachusetts.
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Bouchet CA, Ingram SL. Cannabinoids in the descending pain modulatory circuit: Role in inflammation. Pharmacol Ther 2020; 209:107495. [PMID: 32004514 PMCID: PMC7183429 DOI: 10.1016/j.pharmthera.2020.107495] [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] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 01/17/2020] [Indexed: 01/09/2023]
Abstract
The legalization of cannabis in some states has intensified interest in the potential for cannabis and its constituents to lead to novel therapeutics for pain. Our understanding of the cellular mechanisms underlying cannabinoid actions in the brain have lagged behind opioids; however, the current opioid epidemic has also increased attention on the use of cannabinoids as alternatives to opioids for pain, especially chronic pain that requires long-term use. Endogenous cannabinoids are lipid signaling molecules that have complex roles in modulating neuronal function throughout the brain. In this review, we discuss cannabinoid functions in the descending pain modulatory pathway, a brain circuit that integrates cognitive and emotional processing of pain to modulate incoming sensory inputs. In addition, we highlight areas where further studies are necessary to understand cannabinoid regulation of descending pain modulation.
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Affiliation(s)
- Courtney A Bouchet
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR 97239, United States of America
| | - Susan L Ingram
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR 97239, United States of America.
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9
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Milligan AL, Szabo-Pardi TA, Burton MD. Cannabinoid Receptor Type 1 and Its Role as an Analgesic: An Opioid Alternative? J Dual Diagn 2020; 16:106-119. [PMID: 31596190 PMCID: PMC7007359 DOI: 10.1080/15504263.2019.1668100] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Understanding how the body regulates pain is fundamental to develop rational strategies to combat the growing prevalence of chronic pain states, opioid dependency, and the increased financial burden to the medical care system. Pain is the most prominent reason why Americans seek medical attention and extensive literature has identified the importance of the endocannabinoid pathway in controlling pain. Modulation of the endocannabinoid system offers new therapeutic opportunities for the selective control of excessive neuronal activity in several pain conditions (acute, inflammatory, chronic, and neuropathic). Cannabinoids have a long history of medicinal use and their analgesic properties are well documented; however, there are major impediments to understanding cannabinoid pain modulation. One major issue is the presence of psychotropic side effects associated with D9-tetrahydrocannabinol (THC) or synthetic derivatives, which puts an emphatic brake on their use. This dose-limiting effect prevents the appropriate degree of analgesia . Animal studies have shown that the psychotropic effects are mediated via brain cannabinoid type 1 (CB1) receptors, while analgesic activity in chronic pain states may be mediated via CB1R action in the spinal cord, brainstem, peripheral sensory neurons, or immune cells. The development of appropriate therapies is incumbent on our understanding of the role of peripheral versus central endocannabinoid-driven analgesia. Recent physiological, pharmacological, and anatomical studies provide evidence that one of the main roles of the endocannabinoid system is the regulation of gamma-aminobutyric acid (GABA) and/or glutamate release. This article will review this evidence in the context of its implications for pain. We first provide a brief overview of CB1R's role in the regulation of nociception, followed by a review of the evidence that the peripheral endocannabinoid system modulates nociception. We then look in detail at regulation of central-mediated analgesia, followed up with evidence that cannabinoidmediated modulation of pain involves modulation of GABAergic and glutamatergic neurotransmission in key brain regions. Finally, we discuss cannabinoid action on non-neuronal cells in the context of inflammation and direct modulation of neurons. This work stands to reveal long-standing controversies in the cannabinoid analgesia area that have had an impact on failed clinical trials and implementation of therapeutics targeting this system.
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10
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c-Jun N terminal kinase signaling pathways mediate cannabinoid tolerance in an agonist-specific manner. Neuropharmacology 2019; 164:107847. [PMID: 31758947 DOI: 10.1016/j.neuropharm.2019.107847] [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: 01/26/2018] [Revised: 10/29/2019] [Accepted: 11/06/2019] [Indexed: 12/18/2022]
Abstract
Tolerance to the antinociceptive effects of cannabinoids represents a significant limitation to their clinical use in managing chronic pain. Tolerance likely results from desensitization and down-regulation of the cannabinoid type 1 receptor (CB1R), with CB1R desensitization occurring via phosphorylation of CB1Rs by a G protein-coupled receptor kinase and subsequent association with an arrestin protein. Previous studies have shown that (1) desensitization-resistant S426A/S430A mice exhibit a modest delay in tolerance for Δ9-THC and (-)-CP55,940 but a more pronounced disruption in tolerance for WIN 55,212-2 and (2) that c-Jun N-terminal kinase (JNK) signaling may selectively mediate antinociceptive tolerance to morphine compared to other opioid analgesics. In the current study, we found that pretreatment with the JNK inhibitor SP600125 (3 mg/kg) attenuates tolerance to the antinociceptive in the formalin test and to the anti-allodynic effects of Δ9-THC (6 mg/kg) in cisplatin-evoked neuropathic pain using wild-type mice. We also find that SP600125 causes an especially robust reduction in tolerance to the antinociceptive effects of Δ9-THC (30 mg/kg), but not WIN 55,212-2 (10 mg/kg) in the tail-flick assay using S426A/S430A mice. Interestingly, SP600125 pretreatment accelerated tolerance to the antinociceptive and anti-allodynic effects of (-)-CP55,940 (0.3 mg/kg) in mice with acute and neuropathic pain. These results demonstrate that inhibition of JNK signaling pathways delay tolerance to Δ9-THC, but not to CP55,940 or WIN55,212-2, demonstrating that the mechanisms of cannabinoid tolerance are agonist-specific.
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11
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Characterization of cerebral cortical endocannabinoid levels in a rat inguinal surgery model using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Ir J Psychol Med 2019; 39:54-63. [PMID: 31354118 DOI: 10.1017/ipm.2019.29] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND The brain endocannabinoid system is believed to play significant roles in anti-nociception, fear response, anxiety, and stress. This study investigated the effects of rat inguinal surgery on the levels of endocannabinoids in the cerebral cortex. AIM The aim of this study was to investigate the effects of acute post-surgical pain on the levels of endocannabinoids in the cerebral cortex. METHODS Quantitation of endocannabinoids in the rat cerebral cortex was performed by liquid chromatography-tandem mass spectrometry. RESULTS There was no significant difference in the cerebral cortical levels of anandamide (AEA) and 2-arachidonoylglycerol (2-AG) between the sham and surgery experimental groups. However, there were lateralized differences in the levels of these endocannabinoids between the right and left cerebral cortices irrespective of the two groups. The concentrations of AEA and 2-AG were significantly higher in the right cerebral cortex compared to the contralateral cerebral cortex. CONCLUSION Acute post-surgical pain did not induce significant alterations in the cerebral cortical levels of endocannabinoids in this study, but the phenomenon of lateralization of the cerebral cortical AEA and 2-AG levels was observed; this latter finding may be related to the role played by endocannabinoids in fear conditioning.
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12
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Blanton HL, Brelsfoard J, DeTurk N, Pruitt K, Narasimhan M, Morgan DJ, Guindon J. Cannabinoids: Current and Future Options to Treat Chronic and Chemotherapy-Induced Neuropathic Pain. Drugs 2019; 79:969-995. [PMID: 31127530 PMCID: PMC8310464 DOI: 10.1007/s40265-019-01132-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Increases in cancer diagnosis have tremendous negative impacts on patients and their families, and major societal and economic costs. The beneficial effect of chemotherapeutic agents on tumor suppression comes with major unwanted side effects such as weight and hair loss, nausea and vomiting, and neuropathic pain. Chemotherapy-induced peripheral neuropathy (CIPN), which can include both painful and non-painful symptoms, can persist 6 months or longer after the patient's last chemotherapeutic treatment. These peripheral sensory and motor deficits are poorly treated by our current analgesics with limited effectiveness. Therefore, the development of novel treatment strategies is an important preclinical research focus and an urgent need for patients. Approaches to prevent CIPN have yielded disappointing results since these compounds may interfere with the anti-tumor properties of chemotherapeutic agents. Nevertheless, the first (serotonin noradrenaline reuptake inhibitors [SNRIs], anticonvulsants, tricyclic antidepressants) and second (5% lidocaine patches, 8% capsaicin patches and weak opioids such as tramadol) lines of treatment for CIPN have shown some efficacy. The clinical challenge of CIPN management in cancer patients and the need to target novel therapies with long-term efficacy in alleviating CIPN are an ongoing focus of research. The endogenous cannabinoid system has shown great promise and efficacy in alleviating CIPN in preclinical and clinical studies. In this review, we will discuss the mechanisms through which the platinum, taxane, and vinca alkaloid classes of chemotherapeutics may produce CIPN and the potential therapeutic effect of drugs targeting the endocannabinoid system in preclinical and clinical studies, in addition to cannabinoid compounds diffuse mechanisms of action in alleviation of CIPN.
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Affiliation(s)
- Henry L Blanton
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA
| | - Jennifer Brelsfoard
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA
| | - Nathan DeTurk
- Department of Anesthesiology and Department of Pharmacology, Penn State University College of Medicine, Hershey, PA, 17033, USA
| | - Kevin Pruitt
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, 3601 4th Street STOP 6592, Lubbock, TX, 79430, USA
| | - Madhusudhanan Narasimhan
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA
| | - Daniel J Morgan
- Department of Anesthesiology and Department of Pharmacology, Penn State University College of Medicine, Hershey, PA, 17033, USA
| | - Josée Guindon
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA.
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Schafer SM, Geuter S, Wager TD. Mechanisms of placebo analgesia: A dual-process model informed by insights from cross-species comparisons. Prog Neurobiol 2018; 160:101-122. [PMID: 29108801 PMCID: PMC5747994 DOI: 10.1016/j.pneurobio.2017.10.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 10/24/2017] [Accepted: 10/28/2017] [Indexed: 12/19/2022]
Abstract
Placebo treatments are pharmacologically inert, but are known to alleviate symptoms across a variety of clinical conditions. Associative learning and cognitive expectations both play important roles in placebo responses, however we are just beginning to understand how interactions between these processes lead to powerful effects. Here, we review the psychological principles underlying placebo effects and our current understanding of their brain bases, focusing on studies demonstrating both the importance of cognitive expectations and those that demonstrate expectancy-independent associative learning. To account for both forms of placebo analgesia, we propose a dual-process model in which flexible, contextually driven cognitive schemas and attributions guide associative learning processes that produce stable, long-term placebo effects. According to this model, the placebo-induction paradigms with the most powerful effects are those that combine reinforcement (e.g., the experience of reduced pain after placebo treatment) with suggestions and context cues that disambiguate learning by attributing perceived benefit to the placebo. Using this model as a conceptual scaffold, we review and compare neurobiological systems identified in both human studies of placebo analgesia and behavioral pain modulation in rodents. We identify substantial overlap between the circuits involved in human placebo analgesia and those that mediate multiple forms of context-based modulation of pain behavior in rodents, including forebrain-brainstem pathways and opioid and cannabinoid systems in particular. This overlap suggests that placebo effects are part of a set of adaptive mechanisms for shaping nociceptive signaling based on its information value and anticipated optimal response in a given behavioral context.
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Affiliation(s)
- Scott M Schafer
- Department of Psychology and Neuroscience, University of Colorado, 345 UCB, Boulder, CO 80309, USA
| | - Stephan Geuter
- Department of Psychology and Neuroscience, University of Colorado, 345 UCB, Boulder, CO 80309, USA; Institute of Cognitive Science, University of Colorado Boulder, 344 UCB, Boulder, CO 80309, USA; Department of Biostatistics, Johns Hopkins University, 615 N Wolfe St, Baltimore, MD 21205, USA
| | - Tor D Wager
- Department of Psychology and Neuroscience, University of Colorado, 345 UCB, Boulder, CO 80309, USA; Institute of Cognitive Science, University of Colorado Boulder, 344 UCB, Boulder, CO 80309, USA.
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Boggs DL, Nguyen JD, Morgenson D, Taffe MA, Ranganathan M. Clinical and Preclinical Evidence for Functional Interactions of Cannabidiol and Δ 9-Tetrahydrocannabinol. Neuropsychopharmacology 2018; 43:142-154. [PMID: 28875990 PMCID: PMC5719112 DOI: 10.1038/npp.2017.209] [Citation(s) in RCA: 146] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 08/30/2017] [Accepted: 08/31/2017] [Indexed: 12/21/2022]
Abstract
The plant Cannabis sativa, commonly called cannabis or marijuana, has been used for its psychotropic and mind-altering side effects for millennia. There has been growing attention in recent years on its potential therapeutic efficacy as municipalities and legislative bodies in the United States, Canada, and other countries grapple with enacting policy to facilitate the use of cannabis or its constituents for medical purposes. There are >550 chemical compounds and >100 phytocannabinoids isolated from cannabis, including Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD). THC is thought to produce the main psychoactive effects of cannabis, while CBD does not appear to have similar effects. Studies conflict as to whether CBD attenuates or exacerbates the behavioral and cognitive effects of THC. This includes effects of CBD on THC-induced anxiety, psychosis, and cognitive deficits. In this article, we review the available evidence on the pharmacology and behavioral interactions of THC and CBD from preclinical and human studies, particularly with reference to anxiety and psychosis-like symptoms. Both THC and CBD, as well as other cannabinoid molecules, are currently being evaluated for medicinal purposes, separately and in combination. Future cannabis-related policy decisions should include consideration of scientific findings, including the individual and interactive effects of CBD and THC.
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Affiliation(s)
- Douglas L Boggs
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA,VA Connecticut Healthcare System, West Haven, CT, USA
| | - Jacques D Nguyen
- Department of Neuroscience; The Scripps Research Institute, La Jolla, CA, USA
| | | | - Michael A Taffe
- Department of Neuroscience; The Scripps Research Institute, La Jolla, CA, USA
| | - Mohini Ranganathan
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA,VA Connecticut Healthcare System, West Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, 950 Campbell Avenue, New Haven, CT 06511, USA, Tel: +1 203 932 5711X2546, E-mail:
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Song T, Ma X, Ma P, Gu K, Zhao J, Yang Y, Jiang B, Li Y, Wang C. Administrations of thalidomide into the rostral ventromedial medulla produce antinociceptive effects in a rat model of postoperative pain. J Neurosci Res 2017; 96:273-283. [PMID: 28758232 DOI: 10.1002/jnr.24124] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 06/30/2017] [Accepted: 07/05/2017] [Indexed: 12/14/2022]
Affiliation(s)
- Tieying Song
- Department of Anesthesiology; The First Hospital of Shijiazhuang; No. 36 Fanxi Road, Chang'an District, Shijiazhuang 050011 Hebei province China
| | - Xiaojing Ma
- Department of Anesthesiology; The First Hospital of Shijiazhuang; No. 36 Fanxi Road, Chang'an District, Shijiazhuang 050011 Hebei province China
| | - Pengyu Ma
- Department of Anesthesiology; The First Hospital of Shijiazhuang; No. 36 Fanxi Road, Chang'an District, Shijiazhuang 050011 Hebei province China
| | - Kunfeng Gu
- Department of Anesthesiology; The First Hospital of Shijiazhuang; No. 36 Fanxi Road, Chang'an District, Shijiazhuang 050011 Hebei province China
| | - Jianhui Zhao
- Department of Anesthesiology; The First Hospital of Shijiazhuang; No. 36 Fanxi Road, Chang'an District, Shijiazhuang 050011 Hebei province China
| | - Yunliang Yang
- Department of Anesthesiology; The First Hospital of Shijiazhuang; No. 36 Fanxi Road, Chang'an District, Shijiazhuang 050011 Hebei province China
| | - Bo Jiang
- Department of Anesthesiology; The First Hospital of Shijiazhuang; No. 36 Fanxi Road, Chang'an District, Shijiazhuang 050011 Hebei province China
| | - Yuxia Li
- Department of Anesthesiology; The First Hospital of Shijiazhuang; No. 36 Fanxi Road, Chang'an District, Shijiazhuang 050011 Hebei province China
| | - Chunping Wang
- Department of Anesthesiology; The First Hospital of Shijiazhuang; No. 36 Fanxi Road, Chang'an District, Shijiazhuang 050011 Hebei province China
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Starowicz K, Finn DP. Cannabinoids and Pain: Sites and Mechanisms of Action. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2017; 80:437-475. [PMID: 28826543 DOI: 10.1016/bs.apha.2017.05.003] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The endocannabinoid system, consisting of the cannabinoid1 receptor (CB1R) and cannabinoid2 receptor (CB2R), endogenous cannabinoid ligands (endocannabinoids), and metabolizing enzymes, is present throughout the pain pathways. Endocannabinoids, phytocannabinoids, and synthetic cannabinoid receptor agonists have antinociceptive effects in animal models of acute, inflammatory, and neuropathic pain. CB1R and CB2R located at peripheral, spinal, or supraspinal sites are important targets mediating these antinociceptive effects. The mechanisms underlying the analgesic effects of cannabinoids likely include inhibition of presynaptic neurotransmitter and neuropeptide release, modulation of postsynaptic neuronal excitability, activation of the descending inhibitory pain pathway, and reductions in neuroinflammatory signaling. Strategies to dissociate the psychoactive effects of cannabinoids from their analgesic effects have focused on peripherally restricted CB1R agonists, CB2R agonists, inhibitors of endocannabinoid catabolism or uptake, and modulation of other non-CB1R/non-CB2R targets of cannabinoids including TRPV1, GPR55, and PPARs. The large body of preclinical evidence in support of cannabinoids as potential analgesic agents is supported by clinical studies demonstrating their efficacy across a variety of pain disorders.
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Affiliation(s)
- Katarzyna Starowicz
- Institute of Pharmacology, Polish Academy of Sciences, Laboratory of Pain Pathophysiology, Krakow, Poland
| | - David P Finn
- Pharmacology and Therapeutics, School of Medicine, Galway Neuroscience Centre and Centre for Pain Research, NCBES, National University of Ireland, Galway, Ireland.
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Cannabinoids Activate Monoaminergic Signaling to Modulate Key C. elegans Behaviors. J Neurosci 2017; 37:2859-2869. [PMID: 28188220 DOI: 10.1523/jneurosci.3151-16.2017] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 01/22/2017] [Accepted: 02/01/2017] [Indexed: 12/22/2022] Open
Abstract
Cannabis sativa, or marijuana, a popular recreational drug, alters sensory perception and exerts a range of potential medicinal benefits. The present study demonstrates that the endogenous cannabinoid receptor agonists 2-arachidonoylglycerol (2-AG) and anandamide (AEA) activate a canonical cannabinoid receptor in Caenorhabditis elegans and also modulate monoaminergic signaling at multiple levels. 2-AG or AEA inhibit nociception and feeding through a pathway requiring the cannabinoid-like receptor NPR-19. 2-AG or AEA activate NPR-19 directly and cannabinoid-dependent inhibition can be rescued in npr-19-null animals by the expression of a human cannabinoid receptor, CB1, highlighting the orthology of the receptors. Cannabinoids also modulate nociception and locomotion through an NPR-19-independent pathway requiring an α2A-adrenergic-like octopamine (OA) receptor, OCTR-1, and a 5-HT1A-like serotonin (5-HT) receptor, SER-4, that involves a complex interaction among cannabinoid, octopaminergic, and serotonergic signaling. 2-AG activates OCTR-1 directly. In contrast, 2-AG does not activate SER-4 directly, but appears to enhance SER-4-dependent serotonergic signaling by increasing endogenous 5-HT. This study defines a conserved cannabinoid signaling system in C. elegans, demonstrates the cannabinoid-dependent activation of monoaminergic signaling, and highlights the advantages of studying cannabinoid signaling in a genetically tractable whole-animal model.SIGNIFICANCE STATEMENTCannabis sativa, or marijuana, causes euphoria and exerts a wide range of medicinal benefits. For years, cannabinoids have been studied at the cellular level using tissue explants with conflicting results. To better understand cannabinoid signaling, we have used the Caenorhabditis elegans model to examine the effects of cannabinoids on behavior. The present study demonstrates that mammalian cannabinoid receptor ligands activate a conserved cannabinoid signaling system in C. elegans and also modulate monoaminergic signaling, potentially affecting an array of disorders, including anxiety and depression. This study highlights the potential role of cannabinoids in modulating monoaminergic signaling and the advantages of studying cannabinoid signaling in a genetically tractable, whole-animal model.
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Dean C, Hillard CJ, Seagard JL, Hopp FA, Hogan QH. Upregulation of fatty acid amide hydrolase in the dorsal periaqueductal gray is associated with neuropathic pain and reduced heart rate in rats. Am J Physiol Regul Integr Comp Physiol 2017; 312:R585-R596. [PMID: 28148494 DOI: 10.1152/ajpregu.00481.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 01/26/2017] [Accepted: 01/31/2017] [Indexed: 11/22/2022]
Abstract
Nerve damage can induce a heightened pain response to noxious stimulation, which is termed hyperalgesia. Pain itself acts as a stressor, initiating autonomic and sensory effects through the dorsal periaqueductal gray (dPAG) to induce both sympathoexcitation and analgesia, which prior studies have shown to be affected by endocannabinoid signaling. The present study addressed the hypothesis that neuropathic pain disrupts autonomic and analgesic regulation by endocannabinoid signaling in the dPAG. Endocannabinoid contents, transcript levels of endocannabinoid signaling components, and catabolic enzyme activity were analyzed in the dPAG of rats at 21 days after painful nerve injury. The responses to two nerve injury models were similar, with two-thirds of animals developing hyperalgesia that was maintained throughout the postinjury period, whereas no sustained change in sensory function was observed in the remaining rats. Anandamide content was lower in the dPAG of rats that developed sustained hyperalgesia, and activity of the catabolic enzyme fatty acid amide hydrolase (FAAH) was higher. Intensity of hyperalgesia was correlated to transcript levels of FAAH and negatively correlated to heart rate and sympathovagal balance. These data suggest that maladaptive endocannabinoid signaling in the dPAG after nerve injury could contribute to chronic neuropathic pain and associated autonomic dysregulation. This study demonstrates that reduced anandamide content and upregulation of FAAH in the dPAG are associated with hyperalgesia and reduced heart rate sustained weeks after nerve injury. These data provide support for the evaluation of FAAH inhibitors for the treatment of chronic neuropathic pain.
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Affiliation(s)
- Caron Dean
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin; .,Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin
| | - Cecilia J Hillard
- Department of Pharmacology, Medical College of Wisconsin, Milwaukee, Wisconsin; and
| | - Jeanne L Seagard
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin.,Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin
| | - Francis A Hopp
- Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin
| | - Quinn H Hogan
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin.,Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin
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Almeida RT, Romero TRL, Romero MGMEC, de Souza GG, Perez ADC, Duarte IDG. Endocannabinoid mechanism for orofacial antinociception induced by electroacupuncture in acupoint St36 in rats. Pharmacol Rep 2016; 68:1095-1101. [DOI: 10.1016/j.pharep.2016.07.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 06/28/2016] [Accepted: 07/20/2016] [Indexed: 10/21/2022]
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20
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Silva M, Martins D, Charrua A, Piscitelli F, Tavares I, Morgado C, Di Marzo V. Endovanilloid control of pain modulation by the rostroventromedial medulla in an animal model of diabetic neuropathy. Neuropharmacology 2016; 107:49-57. [PMID: 26965218 DOI: 10.1016/j.neuropharm.2016.03.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 03/01/2016] [Accepted: 03/02/2016] [Indexed: 10/22/2022]
Abstract
The involvement of transient receptor vanilloid type-1 (TRPV1) channels in pain modulation by the brain remains understudied. The rostroventromedial medulla (RVM) plays a key role in conveying to the spinal cord pain modulatory influences triggered in higher brain centres, with co-existence of inhibitory (antinociceptive) and facilitatory (pronociceptive) effects. In spite of some reports of TRPV1 expression in the RVM, it remains unknown if endovanilloid signalling plays a direct role in local pain modulation. Here we used a model of diabetic neuropathy, the streptozotocin (STZ)-diabetic rat, to study the role of endovanilloid signalling in RVM-mediated pain modulation during chronic pain. Four weeks after diabetes induction, the levels of TRPV1 mRNA and fatty acid amide hydrolase (FAAH), a crucial enzyme for endovanilloid catabolism, in the RVM of STZ-diabetic rats were higher than control. The RVM of STZ-diabetic rats presented decreased levels of several TRPV1 endogenous ligands, namely anandamide (AEA), palmitoylethanolamide (PEA) and oleoylethanolamide (OEA). Administration of capsaicin (a TRPV1 agonist) into the RVM decreased nociceptive behavioural responses in the inflammatory phase of the formalin test (phase 2). These findings suggest that diabetic neuropathy induces plastic changes of RVM endovanilloid signalling, indicating that TRPV1 may be a putative target for pain modulation in this chronic pain condition.
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Affiliation(s)
- M Silva
- Departamento de Biologia Experimental, Faculdade de Medicina, Universidade do Porto, Portugal; I3S - Instituto de Inovação e investigação em Saúde, Universidade do Porto, Portugal
| | - D Martins
- Departamento de Biologia Experimental, Faculdade de Medicina, Universidade do Porto, Portugal; I3S - Instituto de Inovação e investigação em Saúde, Universidade do Porto, Portugal
| | - A Charrua
- I3S - Instituto de Inovação e investigação em Saúde, Universidade do Porto, Portugal; Departmento de Doenças Renais, Urológicas e Infecciosas, Faculdade de Medicina, Universidade do Porto, Portugal
| | - F Piscitelli
- Institute of Biomolecular Chemistry of the National Research Council (ICB-CNR), Naples, Italy
| | - I Tavares
- Departamento de Biologia Experimental, Faculdade de Medicina, Universidade do Porto, Portugal; I3S - Instituto de Inovação e investigação em Saúde, Universidade do Porto, Portugal.
| | - C Morgado
- Departamento de Biologia Experimental, Faculdade de Medicina, Universidade do Porto, Portugal; I3S - Instituto de Inovação e investigação em Saúde, Universidade do Porto, Portugal
| | - V Di Marzo
- Institute of Biomolecular Chemistry of the National Research Council (ICB-CNR), Naples, Italy
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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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La Porta C, Bura SA, Negrete R, Maldonado R. Involvement of the endocannabinoid system in osteoarthritis pain. Eur J Neurosci 2014; 39:485-500. [PMID: 24494687 DOI: 10.1111/ejn.12468] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 11/25/2013] [Accepted: 12/02/2013] [Indexed: 12/29/2022]
Abstract
Osteoarthritis is a degenerative joint disease associated with articular cartilage degradation. The major clinical outcome of osteoarthritis is a complex pain state that includes both nociceptive and neuropathic mechanisms. Currently, the therapeutic approaches for osteoarthritis are limited as no drugs are available to control the disease progression and the analgesic treatment has restricted efficacy. Increasing evidence from preclinical studies supports the interest of the endocannabinoid system as an emerging therapeutic target for osteoarthritis pain. Indeed, pharmacological studies have shown the anti-nociceptive effects of cannabinoids in different rodent models of osteoarthritis, and compelling evidence suggests an active participation of the endocannabinoid system in the pathophysiology of this disease. The ubiquitous distribution of cannabinoid receptors, together with the physiological role of the endocannabinoid system in the regulation of pain, inflammation and even joint function further support the therapeutic interest of cannabinoids for osteoarthritis. However, limited clinical evidence has been provided to support this therapeutic use of cannabinoids, despite the promising preclinical data. This review summarizes the promising results that have been recently obtained in support of the therapeutic value of cannabinoids for osteoarthritis management.
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Affiliation(s)
- Carmen La Porta
- Laboratori de Neurofarmacologia, Facultat de Ciències de la Salut i de la Vida, Universitat Pompeu Fabra, C/Dr. Aiguader, 88, Barcelona, 08003, Spain
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Lau BK, Drew GM, Mitchell VA, Vaughan CW. Endocannabinoid modulation by FAAH and monoacylglycerol lipase within the analgesic circuitry of the periaqueductal grey. Br J Pharmacol 2014; 171:5225-36. [PMID: 25041240 DOI: 10.1111/bph.12839] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 06/19/2014] [Accepted: 06/27/2014] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE Endogenous cannabinoids (endocannabinoids) in the periaqueductal grey (PAG) play a vital role in mediating stress-induced analgesia. This analgesic effect of endocannabinoids is enhanced by pharmacological inhibition of their degradative enzymes. However, the specific effects of endocannabinoids and the inhibitors of their degradation are largely unknown within this pain-modulating region. EXPERIMENTAL APPROACH In vitro electrophysiological recordings were conducted from PAG neurons in rat midbrain slices. The effects of the major endocannabinoids and their degradation inhibitors on inhibitory GABAergic synaptic transmission were examined. KEY RESULTS Exogenous application of the endocannabinoid, anandamide (AEA), but not 2-arachidonoylglycerol (2-AG), produced a reduction in inhibitory GABAergic transmission in PAG neurons. This AEA-induced suppression of inhibition was enhanced by the fatty acid amide hydrolase (FAAH) inhibitor, URB597, whereas a 2-AG-induced suppression of inhibition was unmasked by the monoacylglycerol lipase (MGL) inhibitor, JZL184. In addition, application of the CB1 receptor antagonist, AM251, facilitated the basal GABAergic transmission in the presence of URB597 and JZL184, which was further enhanced by the dual FAAH/MGL inhibitor, JZL195. CONCLUSIONS AND IMPLICATIONS Our results indicate that AEA and 2-AG act via disinhibition within the PAG, a cellular action consistent with analgesia. These actions of AEA and 2-AG are tightly regulated by their respective degradative enzymes, FAAH and MGL. Furthermore, individual or combined inhibition of FAAH and/or MGL enhanced tonic disinhibition within the PAG. Therefore, the current findings support the therapeutic potential of FAAH and MGL inhibitors as a novel pharmacotherapy for pain.
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Affiliation(s)
- Benjamin K Lau
- Pain Management Research Institute, Kolling Institute of Medical Research, Northern Clinical School, The University of Sydney at Royal North Shore Hospital, St Leonards, NSW, Australia
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Rea K, Olango WM, Okine BN, Madasu MK, McGuire IC, Coyle K, Harhen B, Roche M, Finn DP. Impaired endocannabinoid signalling in the rostral ventromedial medulla underpins genotype-dependent hyper-responsivity to noxious stimuli. Pain 2014; 155:69-79. [DOI: 10.1016/j.pain.2013.09.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Revised: 08/18/2013] [Accepted: 09/09/2013] [Indexed: 12/20/2022]
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Selley DE, Welch SP, Sim-Selley LJ. Sphingosine lysolipids in the CNS: endogenous cannabinoid antagonists or a parallel pain modulatory system? Life Sci 2013; 93:187-93. [PMID: 23782998 DOI: 10.1016/j.lfs.2013.06.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 06/02/2013] [Accepted: 06/06/2013] [Indexed: 01/02/2023]
Abstract
A significant number of patients experience chronic pain and the intractable side effects of currently prescribed pain medications. Recent evidence indicates important pain-modulatory roles for two classes of G-protein-coupled receptors that are activated by endogenous lipid ligands, the endocannabinoid (eCB) and sphingosine-1-phosphate (S1P) receptors, which are widely expressed in both the immune and nervous systems. In the central nervous system (CNS), CB1 cannabinoid and S1P1 receptors are most abundantly expressed and exhibit overlapping anatomical distributions and similar signaling mechanisms. The eCB system has emerged as a potential target for treatment of chronic pain, but comparatively little is known about the roles of S1P in pain regulation. Both eCB and S1P systems modulate pain perception via the central and peripheral nervous systems. In most paradigms studied, the eCB system mainly inhibits pain perception. In contrast, S1P acting peripherally at S1P1 and S1P3 receptors can enhance sensitivity to various pain stimuli or elicit spontaneous pain. However, S1P acting at S1P1 receptors and possibly other targets in the CNS can attenuate sensitivity to various pain stimuli. Interestingly, other endogenous sphingolipid derivatives might play a role in central pain sensitization. Moreover, these sphingolipids can also act as CB1 cannabinoid receptor antagonists, but the physiological relevance of this interaction is unknown. Overall, both eCB and sphingolipid systems offer promising targets for the treatment of chronic pain. This review compares and contrasts the eCB and S1P systems with a focus on their roles in pain modulation, and considers possible points of interaction between these systems.
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Affiliation(s)
- Dana E Selley
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA 23298, United States.
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Involvement of the opioid and cannabinoid systems in pain control: new insights from knockout studies. Eur J Pharmacol 2013; 716:142-57. [PMID: 23523475 DOI: 10.1016/j.ejphar.2013.01.077] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 01/24/2013] [Accepted: 01/29/2013] [Indexed: 12/20/2022]
Abstract
The endogenous opioid and cannabinoid systems are involved in the physiological inhibitory control of pain and are of particular interest for the development of therapeutic approaches for pain management. The involvement of these endogenous systems in pain control has been studied from decades by the use of compounds with different affinities for each cannabinoid and opioid receptor or for the different enzymes involved in endocannabinoid and endogenous opioid metabolism. However, the selectivity of these pharmacological tools in vivo has represented an important limitation for these studies. The generation of genetically modified mice with selective mutations in specific components of the endocannabinoid and endogenous opioid system has provided important advances in the identification of the specific contribution of each component of these endogenous systems in the perception of noxious stimuli and the development of pathological pain states. Different lines of constitutive and conditional knockout mice deficient in specific cannabinoid and opioid receptors, specific precursors of the endogenous opioid peptides and the main enzymes involved in endocannabinoid and endogenous opioid degradation are now available. These knockout mice have also been used to evaluate the contribution of each component of the endocannabinoid and opioid system in the antinociceptive effects of cannabinoid and opioid agonists, including those currently used to treat pain in humans. This review summarizes the main advances provided in the last 15 years by the use of these genetic tools in the knowledge of the physiological control of pain and the pharmacology of cannabinoid and opioid compounds for pain management.
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28
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Zogopoulos P, Vasileiou I, Patsouris E, Theocharis SE. The role of endocannabinoids in pain modulation. Fundam Clin Pharmacol 2013; 27:64-80. [PMID: 23278562 DOI: 10.1111/fcp.12008] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 09/03/2012] [Accepted: 09/21/2012] [Indexed: 12/16/2022]
Abstract
The endocannabinoid system (ES) is comprised of cannabinoid (CB) receptors, their endogenous ligands (endocannabinoids), and proteins responsible for their metabolism. Endocannabinoids serve as retrograde signaling messengers in GABAergic and glutamatergic synapses, as well as modulators of postsynaptic transmission, that interact with other neurotransmitters. Physiological stimuli and pathological conditions lead to differential increases in brain endocannabinoids that regulate distinct biological functions. Furthermore, endocannabinoids modulate neuronal, glial, and endothelial cell function and exert neuromodulatory, anti-excitotoxic, anti-inflammatory, and vasodilatory effects. Analgesia is one of the principal therapeutic targets of cannabinoids. Cannabinoid analgesia is based on the suppression of spinal and thalamic nociceptive neurons, but peripheral sites of action have also been identified. The chronic pain that occasionally follows peripheral nerve injury differs fundamentally from inflammatory pain and is an area of considerable unmet therapeutic need. Over the last years, considerable progress has been made in understanding the role of the ES in the modulation of pain. Endocannabinoids have been shown to behave as analgesics in models of both acute nociception and clinical pain such as inflammation and painful neuropathy. The framework for such analgesic effects exists in the CB receptors, which are found in areas of the nervous system important for pain processing and in immune cells that regulate the neuro-immune interactions that mediate the inflammatory hyperalgesia. The purpose of this review is to present the available research and clinical data, up to date, regarding the ES and its role in pain modulation, as well as its possible therapeutic perspectives.
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Affiliation(s)
- Panagiotis Zogopoulos
- First Department of Pathology, Medical School, University of Athens, Goudi, Athens, Greece
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Abstract
In recent years, a growing interest has been dedicated to the study of the endocannabinoid system. The isolation of Cannabis sativa main psychotropic compound, Δ(9)-tetrahydrocannabinol (THC), has led to the discovery of an atypical neurotransmission system that modulates the release of other neurotransmitters and participates in many biological processes, including the cascade of inflammatory responses. In this context, cannabinoids have been studied for their possible therapeutic properties in neuroinflammatory diseases. In this review, historic and biochemical aspects of cannabinoids are discussed, as well as their function as modulators of inflammatory processes and therapeutic perspectives for neurodegenerative disorders, particularly, multiple sclerosis.
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Affiliation(s)
- Viviane M Saito
- Laboratory of Immunopharmacology, Graduate Program in Neurosciences, UFMG, Belo Horizonte, Brazil
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Mostafeezur RM, Zakir HM, Takatsuji H, Yamada Y, Yamamura K, Kitagawa J. Cannabinoids facilitate the swallowing reflex elicited by the superior laryngeal nerve stimulation in rats. PLoS One 2012; 7:e50703. [PMID: 23209814 PMCID: PMC3507745 DOI: 10.1371/journal.pone.0050703] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Accepted: 10/25/2012] [Indexed: 12/03/2022] Open
Abstract
Cannabinoids have been reported to be involved in affecting various biological functions through binding with cannabinoid receptors type 1 (CB1) and 2 (CB2). The present study was designed to investigate whether swallowing, an essential component of feeding behavior, is modulated after the administration of cannabinoid. The swallowing reflex evoked by the repetitive electrical stimulation of the superior laryngeal nerve in rats was recorded before and after the administration of the cannabinoid receptor agonist, WIN 55-212-2 (WIN), with or without CB1 or CB2 antagonist. The onset latency of the first swallow and the time intervals between swallows were analyzed. The onset latency and the intervals between swallows were shorter after the intravenous administration of WIN, and the strength of effect of WIN was dose-dependent. Although the intravenous administration of CB1 antagonist prior to intravenous administration of WIN blocked the effect of WIN, the administration of CB2 antagonist did not block the effect of WIN. The microinjection of the CB1 receptor antagonist directly into the nucleus tractus solitarius (NTS) prior to intravenous administration of WIN also blocked the effect of WIN. Immunofluorescence histochemistry was conducted to assess the co-localization of CB1 receptor immunoreactivity to glutamic acid decarboxylase 67 (GAD67) or glutamate in the NTS. CB1 receptor was co-localized more with GAD67 than glutamate in the NTS. These findings suggest that cannabinoids facilitate the swallowing reflex via CB1 receptors. Cannabinoids may attenuate the tonic inhibitory effect of GABA (gamma-aminobuteric acid) neurons in the central pattern generator for swallowing.
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Affiliation(s)
- Rahman Md. Mostafeezur
- Division of Oral Physiology, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Hossain Md. Zakir
- Division of Oral Physiology, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Hanako Takatsuji
- Division of Oral Physiology, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Yoshiaki Yamada
- Division of Oral Physiology, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Kensuke Yamamura
- Division of Oral Physiology, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Junichi Kitagawa
- Division of Oral Physiology, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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Wilson-Poe AR, Pocius E, Herschbach M, Morgan MM. The periaqueductal gray contributes to bidirectional enhancement of antinociception between morphine and cannabinoids. Pharmacol Biochem Behav 2012; 103:444-9. [PMID: 23063785 DOI: 10.1016/j.pbb.2012.10.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 10/02/2012] [Accepted: 10/04/2012] [Indexed: 12/23/2022]
Abstract
Co-administration of opioids and cannabinoids can enhance pain relief even when administered on different days. Repeated systemic administration of morphine has been shown to enhance the antinociceptive effect of tetrahydrocannabinol (THC) administered 12h later, and repeated microinjection of the cannabinoid receptor agonist HU-210 into the ventrolateral periaqueductal gray (PAG) has been shown to enhance the antinociceptive effect of morphine administered 1 day later. The primary objective of the present study was to test the hypothesis that this cannabinoid/opioid interaction is bidirectional. Experiment 1 showed that microinjection of morphine into the ventrolateral PAG of male Sprague-Dawley rats twice daily for 2 days enhanced the antinociceptive effect of HU-210 measured 1 day later. In Experiment 2, twice daily systemic injections of THC enhanced the antinociceptive effect of morphine administered 1 day later. These results complement the previously mentioned studies by showing that morphine and cannabinoid interactions are bidirectional and that the ventrolateral PAG plays an important role in this effect. In contrast to the PAG, repeated administration of HU-210 or the cannabinoid receptor agonist, WIN 55,212-2, into the RVM had a neurotoxic effect. Rats became ill following repeated cannabinoid administration whether given alone or with morphine. Presumably, this neurotoxic effect was caused by the high cannabinoid concentration following RVM microinjection because rats did not become ill following repeated systemic THC administration. These findings indicate that alternating opioid and cannabinoid treatment could produce a longer lasting and more potent analgesia than either compound given alone.
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Affiliation(s)
- Adrianne R Wilson-Poe
- Department of Psychology, Washington State University Vancouver, 14204 NE Salmon Creek Ave, Vancouver, WA 98686-9600, USA
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Dogrul A, Seyrek M, Yalcin B, Ulugol A. Involvement of descending serotonergic and noradrenergic pathways in CB1 receptor-mediated antinociception. Prog Neuropsychopharmacol Biol Psychiatry 2012; 38:97-105. [PMID: 22300745 DOI: 10.1016/j.pnpbp.2012.01.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Revised: 01/03/2012] [Accepted: 01/15/2012] [Indexed: 12/18/2022]
Abstract
Cannabinoids produce antinociceptive and antihyperalgesic effects mainly through activation of the inhibitory CB1 receptors. The demonstration that antinociceptive effects of systemic cannabinoids are significantly diminished following surgical dorsolateral funiculus lesion provides evidence that supraspinal sites and descending pain modulatory pathways play crucial roles in systemic cannabinoid analgesia. In this review, we will firstly provide a background, brief overview of descending modulatory pathways followed by descending pathways implicated in cannabinoid analgesia. We will then describe the recent evidence of the involvement of descending serotonergic and noradrenergic pathways in CB1 receptor-mediated antinociception. This review will provide evidences that systemically administered cannabinoids reinforce the descending serotonergic and noradrenergic pathways to produce acute antinociceptive effects via spinal 5-HT7, 5-HT2A and alpha-2 adrenoceptors activation.
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Affiliation(s)
- Ahmet Dogrul
- Department of Medical Pharmacology, Gulhane Military Academy of Medicine, Ankara, Turkey.
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Eriksen GS, Jacobsen LM, Mahmood A, Pedersen LM, Gjerstad J. Inhibition of fatty acid amide hydrolase (FAAH) reduces spinal nociceptive responses and expression of spinal long-term potentiation (LTP). Brain Res Bull 2012; 87:234-7. [DOI: 10.1016/j.brainresbull.2011.11.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Revised: 10/25/2011] [Accepted: 11/15/2011] [Indexed: 01/11/2023]
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Pava MJ, Blake EM, Green ST, Mizroch BJ, Mulholland PJ, Woodward JJ. Tolerance to cannabinoid-induced behaviors in mice treated chronically with ethanol. Psychopharmacology (Berl) 2012; 219:137-47. [PMID: 21701813 PMCID: PMC3249519 DOI: 10.1007/s00213-011-2387-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Accepted: 06/12/2011] [Indexed: 01/30/2023]
Abstract
RATIONALE Chronic ethanol (EtOH) treatment decreases the motor-impairing effects of cannabinoids and downregulates the cannabinoid type 1 (CB1) receptor. However, these studies have been limited to measures of ataxia and analysis of CB1 expression from whole-brain or hippocampal preparations. OBJECTIVE To more fully assess the interactions between ethanol and cannabinoids, a tetrad of four well-characterized cannabinoid-induced behaviors (hypolocomotion, antinociception, hypothermia, and catalepsy) was measured in mice following EtOH treatment. Additionally, immunoblotting assessed CB1 protein in tissue from nine brain regions associated with these behaviors and the addiction neurocircuitry. MATERIALS AND METHODS Male C57Bl/6J mice were administered EtOH (0, 2, or 4 g/kg; intraperitoneally (i.p.)) twice daily for 10 days. Tetrad behaviors induced by the CB1 agonist WIN 55212-2 (3 mg/kg, i.p.) were measured in subjects 1 or 10 days following the last EtOH injection. In a separate group of animals, tissue was collected at the same time points for immunoblot analysis. RESULTS EtOH-treated mice were less sensitive to the hypothermic, hypolocomotive, and antinociceptive effects of WIN, and this effect reversed to control levels over a 10-day abstinence period. EtOH treatment did not affect WIN-induced catalepsy. CB1 protein expression was significantly altered in several brain areas including the hypothalamus, periaqueductal gray, ventral tegmental area, and cerebellum. CONCLUSIONS These results show that chronic EtOH treatment significantly affects the behavioral sensitivity to cannabinoid drugs and alters CB1 expression in several brain regions. Furthermore, these effects are selective as some behaviors and brain regions display an altered response while others do not.
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Affiliation(s)
- Matthew J. Pava
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC
- Charleston Alcohol Research Center, Medical University of South Carolina, Charleston, SC
| | - Emily M. Blake
- Program in Neuroscience, College of Charleston, Charleston, SC
| | | | | | - Patrick J. Mulholland
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC
- Charleston Alcohol Research Center, Medical University of South Carolina, Charleston, SC
| | - John J. Woodward
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC
- Charleston Alcohol Research Center, Medical University of South Carolina, Charleston, SC
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Escobar W, Ramirez K, Avila C, Limongi R, Vanegas H, Vazquez E. Metamizol, a non-opioid analgesic, acts via endocannabinoids in the PAG-RVM axis during inflammation in rats. Eur J Pain 2011; 16:676-89. [PMID: 22337336 DOI: 10.1002/j.1532-2149.2011.00057.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/17/2011] [Indexed: 12/18/2022]
Abstract
The most commonly used drugs against pain act by inhibiting the cyclooxygenases (COXs). Metamizol (dipyrone) inhibits the COXs and is widely used in Europe and Latin America as a non-opioid analgesic. One target of metamizol and other non-opioid analgesics is the periaqueductal grey matter (PAG), where they trigger descending inhibition of spinal nociceptive transmission. Also, cannabinoids exert an analgesic action at several structures in the peripheral and central nervous system, including the PAG. The present study investigates whether the antinociceptive action of metamizol in the lateral-ventrolateral (LVL) PAG during inflammation is related to endocannabinoids. In anaesthetized rats, unitary action potentials were recorded from spinal nociceptive neurons with receptive fields in the ipsilateral hind paw. Inflammation of the paw induced neuronal hyperexcitability, which was attenuated by intra-LVL-PAG microinjection of metamizol either at the beginning of inflammation or when hyperexcitability was fully established. In both cases, the antinociceptive effect of metamizol was reduced by a microinjection of AM251, an antagonist at the CB1 cannabinoid receptor, either into the LVL-PAG or into the rostral ventromedial medulla (RVM). The RVM is a downstream structure that funnels PAG-derived descending inhibition into the spinal cord. These results show that endocannabinoids and their CB1 receptor (1) contribute at the LVL-PAG to the antinociceptive effects of metamizol, and possibly other non-opioid analgesics; and (2) participate in the PAG-derived activation of RVM descending antinociceptive influences.
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Affiliation(s)
- W Escobar
- Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Venezuela
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Ebrahimzadeh M, Haghparast A. Analgesic effects of cannabinoid receptor agonist WIN55,212-2 in the nucleus cuneiformis in animal models of acute and inflammatory pain in rats. Brain Res 2011; 1420:19-28. [DOI: 10.1016/j.brainres.2011.08.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Revised: 07/31/2011] [Accepted: 08/11/2011] [Indexed: 10/17/2022]
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Akerman S, Holland PR, Goadsby PJ. Diencephalic and brainstem mechanisms in migraine. Nat Rev Neurosci 2011; 12:570-84. [DOI: 10.1038/nrn3057] [Citation(s) in RCA: 385] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Seyrek M, Kahraman S, Deveci MS, Yesilyurt O, Dogrul A. Systemic cannabinoids produce CB1-mediated antinociception by activation of descending serotonergic pathways that act upon spinal 5-HT7 and 5-HT2A receptors. Eur J Pharmacol 2010; 649:183-94. [DOI: 10.1016/j.ejphar.2010.09.039] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 07/24/2010] [Accepted: 09/14/2010] [Indexed: 12/27/2022]
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The Role of Cannabinoid Receptors in the Descending Modulation of Pain. Pharmaceuticals (Basel) 2010; 3:2661-2673. [PMID: 27713370 PMCID: PMC4033943 DOI: 10.3390/ph3082661] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 07/30/2010] [Accepted: 08/16/2010] [Indexed: 11/27/2022] Open
Abstract
The endogenous antinociceptive descending pathway represents a circuitry of the supraspinal central nervous system whose task is to counteract pain. It includes the periaqueductal grey (PAG)-rostral ventromedial medulla (RVM)-dorsal horn (DH) axis, which is the best characterized pain modulation system through which pain is endogenously inhibited. Thus, an alternative rational strategy for silencing pain is the activation of this anatomical substrate. Evidence of the involvement of cannabinoid receptors (CB) in the supraspinal modulation of pain can be found in several studies in which intra-cerebral microinjections of cannabinoid ligands or positive modulators have proved to be analgesic in different pain models, whereas cannabinoid receptor antagonists or antisense nucleotides towards CB1 receptors have facilitated pain. Like opioids, cannabinoids produce centrally-mediated analgesia by activating a descending pathway which includes PAG and its projection to downstream RVM neurons, which in turn send inhibitory projections to the dorsal horn of the spinal cord. Indeed, several studies underline a supraspinal regulation of cannabinoids on γ-aminobutyric acid (GABA) and glutamate release which inhibit and enhance the antinociceptive descending pathway, respectively. Cannabinoid receptor activation expressed on presynaptic GABAergic terminals reduces the probability of neurotransmitter release thus dis-inhibiting the PAG-RVM-dorsal horn antinociceptive pathway. Cannabinoids seem to increase glutamate release (maybe as consequence of GABA decrease) and to require glutamate receptor activation to induce antinociception. The consequent outcome is behavioral analgesia, which is reproduced in several pain conditions, from acute to chronic pain models such as inflammatory and neuropathic pain. Taken together these findings would suggest that supraspinal cannabinoid receptors have broad applications, from pain control to closely related central nervous system diseases such as anxiety and depression.
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40
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Palazzos E, de Novellis V, Marabese I, Rossi F, Maione S. Metabotropic glutamate and cannabinoid receptor crosstalk in periaqueductal grey pain processing. Curr Neuropharmacol 2010; 4:225-31. [PMID: 18615148 DOI: 10.2174/157015906778019545] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Revised: 06/09/2006] [Accepted: 06/29/2006] [Indexed: 11/22/2022] Open
Abstract
Metabotropic glutamate (mGlu) and cannabinoid receptors are G-protein coupled receptors which have shown synaptic co-operation through small lipid messengers in the central nervous system (CNS). A functional interaction between these two receptor families could have a relevant potential in the treatment of CNS disorders, including chronic pain. Indeed, both mGlu and cannabinoid receptors play a crucial role in the neurobiology of pain and their simultaneous manipulation could lead to novel strategies in pain management. In particular, as both mGlu and cannabinoid receptors have been found in the periaqueductal gray (PAG), a crucial station in the pain modulatory system, these receptors could be a substrate for producing analgesia at this level. In this review we aim to briefly illustrate the role of mGlu and can-nabinoid receptors in controlling nociceptive processes, some points of convergence, and their functional interaction in pain processing. Further insights into this functional linkage between the mGlu and cannabinoid receptors could pave the way to a new strategy for pain relief, such as a drug cocktail acting on cannabinoid/metabotropic glutamate receptors.
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Affiliation(s)
- E Palazzos
- Department of Experimental Medicine- Section of Pharmacology "L. Donatelli", Faculty of Medicine and Surgery, Second University of Naples, Via Costantinopoli 16, 80138 Naples, Italy.
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NSAIDs, Opioids, Cannabinoids and the Control of Pain by the Central Nervous System. Pharmaceuticals (Basel) 2010; 3:1335-1347. [PMID: 27713305 PMCID: PMC4033984 DOI: 10.3390/ph3051335] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Revised: 04/14/2010] [Accepted: 04/21/2010] [Indexed: 02/02/2023] Open
Abstract
Nonsteroidal anti-inflammatory drugs (NSAIDs) act upon peripheral tissues and upon the central nervous system to produce analgesia. A major central target of NSAIDs is the descending pain control system. The rostral structures of the descending pain control system send impulses towards the spinal cord and regulate the transmission of pain messages. Key structures of the descending pain control system are the periaqueductal gray matter (PAG) and the rostral ventromedial region of the medulla (RVM), both of which are critical targets for endogenous opioids and opiate pharmaceuticals. NSAIDs also act upon PAG and RVM to produce analgesia and, if repeatedly administered, induce tolerance to themselves and cross-tolerance to opioids. Experimental evidence shows that this is due to an interaction of NSAIDs with endogenous opioids along the descending pain control system. Analgesia by NSAIDs along the descending pain control system also requires an activation of the CB1 endocannabinoid receptor. Several experimental approaches suggest that opioids, NSAIDs and cannabinoids in PAG and RVM cooperate to decrease GABAergic inhibition and thus enhance the descending flow of impulses that inhibit pain.
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Turcotte D, Le Dorze JA, Esfahani F, Frost E, Gomori A, Namaka M. Examining the roles of cannabinoids in pain and other therapeutic indications: a review. Expert Opin Pharmacother 2010; 11:17-31. [PMID: 20001426 DOI: 10.1517/14656560903413534] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
IMPORTANCE OF THE FIELD In recent times, our knowledge of cannabinoids and the endocannabinoid system has greatly advanced. With expanding knowledge, synthetic cannabinoids - including nabilone, dronabinol and a combination of synthetic Delta9-THC and cannabidiol - have been developed and tested for benefit in a variety of therapeutic indications. AREAS COVERED IN THIS REVIEW The aim of this article is to provide a summative review of the vast amount of clinical trial data now available on these agents. WHAT THE READER WILL GAIN To locate clinical trials for review, a literature search was performed using PubMed between the dates of 25 May and 30 June 2009. Search parameters were set to isolate only human randomized controlled trials (RCTs) published between 1990 and 2009. Keywords consistently used for each search include: cannabinoids, marijuana, THC, nabilone and dronabinol. Preferential selection was given to the best-designed trials, focusing on placebo-controlled, double-blind RCTs with the largest patient populations, if available. TAKE HOME MESSAGE As efficacy and tolerability of these agents remain questionable, it is important that cannabinoids not be considered 'first-line' therapies for conditions for which there are more supported and better-tolerated agents. Instead, these agents could be considered in a situation of treatment failure with standard therapies or as adjunctive agents where appropriate.
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Affiliation(s)
- Dana Turcotte
- University of Manitoba, Faculty of Pharmacy, 750 McDermot Avenue, Winnipeg, Manitoba, R3E 0T5 Canada.
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Guindon J, Hohmann AG. The endocannabinoid system and pain. CNS & NEUROLOGICAL DISORDERS DRUG TARGETS 2009; 8:403-21. [PMID: 19839937 DOI: 10.2174/187152709789824660] [Citation(s) in RCA: 307] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Accepted: 06/24/2009] [Indexed: 12/29/2022]
Abstract
The therapeutic potential of cannabinoids has been the topic of extensive investigation following the discovery of cannabinoid receptors and their endogenous ligands. Cannabinoid receptors and their endogenous ligands are present at supraspinal, spinal and peripheral levels. Cannabinoids suppress behavioral responses to noxious stimulation and suppress nociceptive processing through activation of cannabinoid CB(1) and CB(2) receptor subtypes. Endocannabinoids, the brain's own cannabis-like substances, share the same molecular target as Delta(9)-tetrahydrocannabinol, the main psychoactive component in cannabis. Endocannabinoids serve as synaptic circuit breakers and regulate multiple physiological and pathological conditions, e.g. regulation of food intake, immunomodulation, inflammation, analgesia, cancer, addictive behavior, epilepsy and others. This review will focus on uncovering the roles of anandamide and 2-arachidonoylglycerol, the two best characterized endocannabinoids identified to date, in controlling nociceptive responding. The roles of anandamide and 2-arachidonoylglycerol, released under physiological conditions, in modulating nociceptive responding at different levels of the neuraxis will be emphasized in this review. Effects of modulation of endocannabinoid levels through inhibition of endocannabinoid hydrolysis and uptake is also compared with effects of exogenous administration of synthetic endocannabinoids in acute, inflammatory and neuropathic pain models. Finally, the therapeutic potential of the endocannabinoid signaling system is discussed in the context of identifying novel pharmacotherapies for the treatment of pain.
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Affiliation(s)
- Josée Guindon
- Neuroscience and Behavior Program, Department of Psychology, University of Georgia, Athens, GA 30602-3013, USA
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44
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Abstract
Humans have used Cannabis sativa (marijuana) for at least 12,000 years, but researchers have only recently described an endogenous cannabinoid system. The endocannabinoid system modulates an array of physiological and psychological functions. Endocannabinoids are widely distributed throughout the body, including the central nervous system (CNS). This article gives a basic overview of endocannabinoid neuroanatomy and function. Several endocannabinoids have been discovered to date, and their roles are being elucidated. Two G-protein coupled cannabinoid receptors, CB1R and CB2R, have been identified, although other candidate receptors exist, including ion channel and nuclear receptors that might be components of the endocannabinoid system. It appears that cannabinoids are dysregulated in a number of psychiatric disorders and might be involved in their pathogenesis. There is now evidence that manipulation of the endocannabinoid system could be a therapeutic target for a variety of conditions.
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Affiliation(s)
- Chris S Breivogel
- Department of Pharmaceutical Sciences, Campbell University School of Pharmacy, Buies Creek, North Carolina 27506, USA.
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45
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Kunos G, Osei-Hyiaman D, Bátkai S, Sharkey KA, Makriyannis A. Should peripheral CB(1) cannabinoid receptors be selectively targeted for therapeutic gain? Trends Pharmacol Sci 2008; 30:1-7. [PMID: 19042036 DOI: 10.1016/j.tips.2008.10.001] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Revised: 10/13/2008] [Accepted: 10/15/2008] [Indexed: 01/09/2023]
Abstract
Endocannabinoids, endogenous lipid ligands of cannabinoid receptors, mediate a variety of effects similar to those of marijuana. Cannabinoid CB(1) receptors are highly abundant in the brain and mediate psychotropic effects, which limits their value as a potential therapeutic target. There is growing evidence for CB(1) receptors in peripheral tissues that modulate a variety of functions, including pain sensitivity and obesity-related hormonal and metabolic abnormalities. In this review we propose that selective targeting of peripheral CB(1) receptors has potential therapeutic value because it would help to minimize addictive, psychoactive effects in the case of CB(1) agonists used as analgesics, or depression and anxiety in the case of CB(1) antagonists used in the management of cardiometabolic risk factors associated with the metabolic syndrome.
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Affiliation(s)
- George Kunos
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD 20892, USA.
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Non-opioid antinociception produced by brain stem injections of improgan: significance of local, but not cross-regional, cannabinoid mechanisms. Brain Res 2008; 1247:62-70. [PMID: 18983834 DOI: 10.1016/j.brainres.2008.10.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2008] [Revised: 10/02/2008] [Accepted: 10/03/2008] [Indexed: 11/24/2022]
Abstract
Improgan, a cimetidine derivative which lacks activity at known histamine, opioid or cannabinoid receptors, acts by an unknown mechanism in the periaqueductal gray (PAG) and raphe magnus (RM) to stimulate descending, analgesic circuits. These circuits may utilize cannabinoid mechanisms. To characterize further the nature of these circuits, the effects of intracerebral (i.c.) microinjections of rimonabant (a CB(1) receptor inverse agonist) were studied on antinociceptive responses following i.c. microinjections of improgan and the cannabinoid agonist WIN 55,212 (WIN) in rats. Separate intra-RM injections of improgan (30 microg) and WIN (8 microg) produced near-maximal antinociception on both the hot plate (HP) and tail flick (TF) nociceptive tests. Pretreatment with intra-RM rimonabant (20 microg) antagonized the antinociception produced by both intra-RM improgan and intra-RM WIN, but had no effects when given alone. Similar studies with improgan demonstrated rimonabant-sensitive sites within the dorsal and ventrolateral PAG. However, intra-RM pretreatment with rimonabant had no effect on antinociceptive responses following intra-PAG improgan. These studies show that improgan activates pain-relieving mechanisms in the PAG and the RM, both of which may utilize local cannabinoid mechanisms.
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Repeated cannabinoid injections into the rat periaqueductal gray enhance subsequent morphine antinociception. Neuropharmacology 2008; 55:1219-25. [PMID: 18723035 DOI: 10.1016/j.neuropharm.2008.07.038] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Revised: 07/28/2008] [Accepted: 07/29/2008] [Indexed: 01/02/2023]
Abstract
Cannabinoids and opiates inhibit pain, in part, by activating the periaqueductal gray (PAG). Evidence suggests this activation occurs through distinct mechanisms. If the antinociceptive mechanisms are distinct, then cross-tolerance between opioids and cannabinoids should not develop. This hypothesis was tested by measuring the antinociceptive effect of microinjecting morphine into the ventrolateral PAG of rats pretreated with the cannabinoid HU-210 for two days. Male Sprague-Dawley rats were injected twice a day for two days with vehicle (0.4 microL), morphine (5 microg/0.4 microL), HU-210 (5 microg/0.4 microL), or morphine combined with HU-210 into the ventrolateral PAG. Repeated injections of morphine caused a rightward shift in the morphine dose-response curve on Day 3 (i.e., tolerance developed). No tolerance was evident in rats pretreated with morphine combined with HU-210. In rats pretreated with HU-210 alone, morphine antinociception was enhanced. This enhancement was blocked by pretreating rats with the cannabinoid receptor antagonist AM-251, and it also disappeared when rats were tested one week later. Acute microinjection of HU-210 into the PAG antagonized morphine antinociception, suggesting that HU-210-induced enhancement of morphine antinociception is a compensatory response. As hypothesized, there was no evidence of cross-tolerance between morphine and HU-210. In fact, cannabinoid pretreatment enhanced the antinociceptive effect of microinjecting morphine into the ventrolateral PAG. These findings suggest that alternating opioid and cannabinoid treatment could be therapeutically advantageous by preventing the development of tolerance and enhancing morphine antinociception.
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Shimizu T, Yokotani K. Bidirectional roles of the brain 2-arachidonoyl-sn-glycerol in the centrally administered vasopressin-induced adrenomedullary outflow in rats. Eur J Pharmacol 2008; 582:62-9. [DOI: 10.1016/j.ejphar.2007.12.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2007] [Revised: 12/05/2007] [Accepted: 12/20/2007] [Indexed: 12/01/2022]
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Kalbasi Anaraki D, Sianati S, Sadeghi M, Ghasemi M, Paydar MJ, Javadi P, Ejtemaei Mehr S, Dehpour AR. Modulation by female sex hormones of the cannabinoid-induced catalepsy and analgesia in ovariectomized mice. Eur J Pharmacol 2008; 586:189-96. [PMID: 18371951 DOI: 10.1016/j.ejphar.2008.02.055] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2007] [Revised: 01/23/2008] [Accepted: 02/20/2008] [Indexed: 10/22/2022]
Abstract
Cannabinoids are psychoactive compounds with many pharmacological properties such as analgesia, sedation and catalepsy most of which are mediated by cannabinoid CB1 receptors. In the present study, we evaluated whether the ovarian sex hormones are involved in the cannabinoid-induced catalepsy and analgesia in ovariectomized female mice. Female NMRI mice (weighing 25-30 g) were divided into 3 main groups: unoperated, sham-operated and ovariectomized. Both the catalepsy and analgesia induced by different doses of the synthetic cannabinoid WIN 55,212-2 (2 and 4 mg/kg, i.p.) were examined in the groups in the presence or absence of the cannabinoid CB1 antagonist AM251 (0.5 mg/kg). We also evaluated effects of estradiol valerate (10 mg/kg) and progesterone (25 mg/kg) on catalepsy and analgesia induced by WIN 55,212-2 in ovariectomized mice. The antinociceptive effect of WIN 55,212-2 was significantly (P<0.01) enhanced in ovariectomized mice, which was prevented by pretreatment with estradiol but not by progesterone. There was no significant difference in the cannabinoid-induced catalepsy between control and ovariectomized mice. However, pretreatment with progesterone but not estradiol potentiated the cataleptic effect of low dose of WIN 55,212-2 (2 mg/kg) in ovariectomized mice (P<0.01). The present data demonstrated for the first time that ovarian sex steroids could modulate both cannabinoid-induced catalepsy and analgesia in female ovariectomized mice.
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Affiliation(s)
- Dina Kalbasi Anaraki
- Department of Pharmacology, School of Medicine, Medical Sciences/University of Tehran, P.O. Box: 13145-784, Tehran, Iran
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Davis MP. Oral nabilone capsules in the treatment of chemotherapy-induced nausea and vomiting and pain. Expert Opin Investig Drugs 2007; 17:85-95. [DOI: 10.1517/13543784.17.1.85] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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