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Linde LD, Ogryzlo CM, Choles CM, Cairns BE, Kramer JLK. Efficacy of topical cannabinoids in the management of pain: a systematic review and meta-analysis of animal studies. Reg Anesth Pain Med 2022; 47:183-191. [PMID: 35012994 DOI: 10.1136/rapm-2021-102719] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 12/12/2021] [Indexed: 02/01/2023]
Abstract
BACKGROUND/IMPORTANCE Cannabinoids are emerging as an alternative pain management option, preliminarily supported by preclinical and clinical studies. Unwanted side effects from oral or inhaled cannabinoids remain, however, a major barrier to widespread use. Peripherally acting cannabinoids (eg, topically applied) may circumvent these side effects while providing localized pain management. OBJECTIVE Our purpose was to systematically review the literature on the effectiveness of peripherally acting cannabinoids for pain management. EVIDENCE REVIEW We searched MEDLINE, EMBASE, CENTRAL, CINAHL, and PubMed databases. Included studies examined the effect of topical/peripherally administered cannabinoids on pain ratings in humans, as well as pain-related outcomes in animals (eg, paw withdrawal). Due to a lack of trials, human studies were summarized in a narrative synthesis. Separate meta-analyses were performed for animal studies using radiant tail flick or paw withdrawal outcomes. FINDINGS Our search yielded 1182 studies following removal of duplicates, with 46 studies (6 human, 40 animal) included. Human studies (one randomized controlled trial and five case studies/series) reported no adverse events to topical cannabinoids and preliminary evidence of decreased pain ratings. Animal studies reporting tail flick (5) (2.81, 95% CI 1.93 to 3.69, p<0.001) and mechanical withdrawal (11) (2.74, 95% CI 1.82 to 3.67, p<0.001) reported prolonged responses (analgesia) in peripheral cannabinoid groups compared with controls. CONCLUSIONS Preclinical animal studies provided low-quality evidence for peripherally administered cannabinoids to provide regional, antinociceptive effects. The scarcity of high-quality human studies underscores the need to translate preclinical evidence into well-controlled human trials.
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Affiliation(s)
- Lukas D Linde
- International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada .,Department of Anesthesiology, Pharmacology & Therapeutics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Carey M Ogryzlo
- International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Cassandra M Choles
- International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Brian E Cairns
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, Canada
| | - John L K Kramer
- International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada.,Department of Anesthesiology, Pharmacology & Therapeutics, The University of British Columbia, Vancouver, British Columbia, Canada
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Finn DP, Haroutounian S, Hohmann AG, Krane E, Soliman N, Rice ASC. Cannabinoids, the endocannabinoid system, and pain: a review of preclinical studies. Pain 2021; 162:S5-S25. [PMID: 33729211 PMCID: PMC8819673 DOI: 10.1097/j.pain.0000000000002268] [Citation(s) in RCA: 70] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 03/10/2021] [Indexed: 12/13/2022]
Abstract
ABSTRACT This narrative review represents an output from the International Association for the Study of Pain's global task force on the use of cannabis, cannabinoids, and cannabis-based medicines for pain management, informed by our companion systematic review and meta-analysis of preclinical studies in this area. Our aims in this review are (1) to describe the value of studying cannabinoids and endogenous cannabinoid (endocannabinoid) system modulators in preclinical/animal models of pain; (2) to discuss both pain-related efficacy and additional pain-relevant effects (adverse and beneficial) of cannabinoids and endocannabinoid system modulators as they pertain to animal models of pathological or injury-related persistent pain; and (3) to identify important directions for future research. In service of these goals, this review (1) provides an overview of the endocannabinoid system and the pharmacology of cannabinoids and endocannabinoid system modulators, with specific relevance to animal models of pathological or injury-related persistent pain; (2) describes pharmacokinetics of cannabinoids in rodents and humans; and (3) highlights differences and discrepancies between preclinical and clinical studies in this area. Preclinical (rodent) models have advanced our understanding of the underlying sites and mechanisms of action of cannabinoids and the endocannabinoid system in suppressing nociceptive signaling and behaviors. We conclude that substantial evidence from animal models supports the contention that cannabinoids and endocannabinoid system modulators hold considerable promise for analgesic drug development, although the challenge of translating this knowledge into clinically useful medicines is not to be underestimated.
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Affiliation(s)
- David P Finn
- Pharmacology and Therapeutics, School of Medicine, Galway Neuroscience Centre and Centre for Pain Research, Human Biology Building, National University of Ireland Galway, University Road, Galway, Ireland
| | - Simon Haroutounian
- Department of Anesthesiology and Washington University Pain Center, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
| | - Andrea G Hohmann
- Psychological and Brain Sciences, Program in Neuroscience, and Gill Center for Biomolecular Science, Indiana University, Bloomington, IN, USA
| | - Elliot Krane
- Departments of Anesthesiology, Perioperative, and Pain Medicine, & Pediatrics, Stanford University School of Medicine, Stanford, California, USA
| | - Nadia Soliman
- Pain Research, Department of Surgery & Cancer, Faculty of Medicine, Imperial College London, UK
| | - Andrew SC Rice
- Pain Research, Department of Surgery & Cancer, Faculty of Medicine, Imperial College London, UK
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Xing XX, Hua XY, Zheng MX, Ma ZZ, Huo BB, Wu JJ, Ma SJ, Ma J, Xu JG. Intra and inter: Alterations in functional brain resting-state networks after peripheral nerve injury. Brain Behav 2020; 10:e01747. [PMID: 32657022 PMCID: PMC7507705 DOI: 10.1002/brb3.1747] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 05/18/2020] [Accepted: 06/04/2020] [Indexed: 12/16/2022] Open
Abstract
INTRODUCTION Numerous treatments suggest that brain plasticity changes after peripheral nerve injury (PNI), and most studies examining functional magnetic resonance imaging focused on abnormal changes in specific brain regions. However, it is the large-scale interaction of neuronal networks instead of isolated brain regions contributed to the functional recovery after PNI. In the present study, we examined the intra- and internetworks alterations between the related functional resting-state networks (RSNs) in a sciatic nerve injury rat model. METHODS Ninety-six female rats were divided into a control and model group. Unilateral sciatic nerve transection and direct anastomosis were performed in the latter group. We used an independent component analysis (ICA) algorithm to observe the changes in RSNs and assessed functional connectivity between different networks using the functional networks connectivity (FNC) toolbox. RESULTS Six RSNs related to PNI were identified, including the basal ganglia network (BGN), sensorimotor network (SMN), salience network (SN), interoceptive network (IN), cerebellar network (CN), and default mode network (DMN). The model group showed significant changes in whole-brain FC changes within these resting-state networks (RSNs), but four of these RSNs exhibited a conspicuous decrease. The interalterations performed that significantly decreased FNC existed between the BGN and SMN, BGN and IN, and BGN and DMN (p < .05, corrected). A significant increase in FNC existed between DMN and CN and between CN and SN (p < .05, corrected). CONCLUSION The results showed the large-scale functional reorganization at the network level after PNI. This evidence reveals new implications to the pathophysiological mechanisms in brain plasticity of PNI.
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Affiliation(s)
- Xiang-Xin Xing
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Xu-Yun Hua
- Department of Traumatology and Orthopedics, Yueyang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China.,Yangzhi Rehabilitation Hospital, Tongji University, Shanghai, China
| | - Mou-Xiong Zheng
- Department of Traumatology and Orthopedics, Yueyang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Zhen-Zhen Ma
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Bei-Bei Huo
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jia-Jia Wu
- Center of Rehabilitation Medicine, Yueyang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Shu-Jie Ma
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jie Ma
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jian-Guang Xu
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China.,Center of Rehabilitation Medicine, Yueyang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
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Local low dose curcumin treatment improves functional recovery and remyelination in a rat model of sciatic nerve crush through inhibition of oxidative stress. Neuropharmacology 2018; 139:98-116. [PMID: 30018000 DOI: 10.1016/j.neuropharm.2018.07.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 05/16/2018] [Accepted: 07/02/2018] [Indexed: 12/12/2022]
Abstract
Traumatic injuries to peripheral nerves are frequent, however, specific pharmacological treatments are currently lacking. Curcumin has antioxidant, anti-inflammatory and neuroprotective properties but high oral doses are required for therapeutic use, particularly due to its low bioavailability. The aim of the present study was to investigate the effects of local and continuous treatment using low curcumin doses on functional recovery and nerve regeneration after rat sciatic nerve crush (SNC). Curcumin was administered by osmotic pumps with a catheter delivering the drug at the injury site (0.2 mg/day for 4 weeks). Functionally, early improvements in mechanical sensitivity, finger spacing of the injured paw, skilful walking and grip strength were observed in curcumin-treated animals. The curcumin treatment increased expression of compact myelin proteins (MPZ and PMP22), myelin sheath thickness and, correspondingly, increased motor and sensitive nerve conduction velocity. Microscopic analysis of gastrocnemius muscle indicated a curcumin-induced decrease in neurogenic lesions. Curcumin treatment reduced the production of reactive oxygen species (ROS) (which were notably produced by macrophages), lipid peroxidation and increased expression of transcription factor Nrf2. In silico analyses indicated that curcumin combines all the characteristics required to be an efficient lipid peroxidation inhibitor at the heart of biological membranes, hence protecting their degradation due to ROS. This antioxidant capacity is likely to contribute to the beneficial effects of curcumin after SNC injury. These results demonstrate that, when administrated locally, low doses of curcumin represent a promising therapy for peripheral nerve regeneration.
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Donertas B, Unel CC, Erol K. Cannabinoids and agmatine as potential therapeutic alternatives for cisplatin-induced peripheral neuropathy. J Exp Pharmacol 2018; 10:19-28. [PMID: 29950907 PMCID: PMC6018893 DOI: 10.2147/jep.s162059] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Cisplatin is a widely used antineoplastic agent in the treatment of various cancers. Peripheral neuropathy is a well-known side effect of cisplatin and has the potential to result in limiting and/or reducing the dose, decreasing the quality of life. Unfortunately, the mechanism for cisplatin-induced neuropathy has not been completely elucidated. Currently, available treatments for neuropathic pain (NP) are mostly symptomatic, insufficient and are often linked with several detrimental side effects; thus, effective treatments are needed. Cannabinoids and agmatine are endogenous modulators that are implicated in painful states. This review explains the cisplatin-induced neuropathy and antinociceptive effects of cannabinoids and agmatine in animal models of NP and their putative therapeutic potential in cisplatin-induced neuropathy.
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Affiliation(s)
- Basak Donertas
- Department of Medical Pharmacology, Faculty of Medicine, Eskisehir Osmangazi University, Eskisehir, Turkey
| | - Cigdem Cengelli Unel
- Department of Medical Pharmacology, Faculty of Medicine, Eskisehir Osmangazi University, Eskisehir, Turkey
| | - Kevser Erol
- Department of Medical Pharmacology, Faculty of Medicine, Eskisehir Osmangazi University, Eskisehir, Turkey
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Donvito G, Nass SR, Wilkerson JL, Curry ZA, Schurman LD, Kinsey SG, Lichtman AH. The Endogenous Cannabinoid System: A Budding Source of Targets for Treating Inflammatory and Neuropathic Pain. Neuropsychopharmacology 2018; 43:52-79. [PMID: 28857069 PMCID: PMC5719110 DOI: 10.1038/npp.2017.204] [Citation(s) in RCA: 181] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 08/24/2017] [Accepted: 08/27/2017] [Indexed: 02/07/2023]
Abstract
A great need exists for the development of new medications to treat pain resulting from various disease states and types of injury. Given that the endogenous cannabinoid (that is, endocannabinoid) system modulates neuronal and immune cell function, both of which play key roles in pain, therapeutics targeting this system hold promise as novel analgesics. Potential therapeutic targets include the cannabinoid receptors, type 1 and 2, as well as biosynthetic and catabolic enzymes of the endocannabinoids N-arachidonoylethanolamine and 2-arachidonoylglycerol. Notably, cannabinoid receptor agonists as well as inhibitors of endocannabinoid-regulating enzymes fatty acid amide hydrolase and monoacylglycerol lipase produce reliable antinociceptive effects, and offer opioid-sparing antinociceptive effects in myriad preclinical inflammatory and neuropathic pain models. Emerging clinical studies show that 'medicinal' cannabis or cannabinoid-based medications relieve pain in human diseases such as cancer, multiple sclerosis, and fibromyalgia. However, clinical data have yet to demonstrate the analgesic efficacy of inhibitors of endocannabinoid-regulating enzymes. Likewise, the question of whether pharmacotherapies aimed at the endocannabinoid system promote opioid-sparing effects in the treatment of pain reflects an important area of research. Here we examine the preclinical and clinical evidence of various endocannabinoid system targets as potential therapeutic strategies for inflammatory and neuropathic pain conditions.
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Affiliation(s)
- Giulia Donvito
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA, USA
| | - Sara R Nass
- Department of Psychology, West Virginia University, Morgantown, WV, USA
| | - Jenny L Wilkerson
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA, USA
| | - Zachary A Curry
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA, USA
| | - Lesley D Schurman
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA, USA
| | - Steven G Kinsey
- Department of Psychology, West Virginia University, Morgantown, WV, USA
| | - Aron H Lichtman
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA, USA
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7
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Sideris A, Piskoun B, Russo L, Norcini M, Blanck T, Recio-Pinto E. Cannabinoid 1 receptor knockout mice display cold allodynia, but enhanced recovery from spared-nerve injury-induced mechanical hypersensitivity. Mol Pain 2016; 12:12/0/1744806916649191. [PMID: 27206660 PMCID: PMC4956369 DOI: 10.1177/1744806916649191] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 03/04/2016] [Indexed: 01/07/2023] Open
Abstract
Background The function of the Cannabinoid 1 receptor (CB1R) in the development of neuropathic pain is not clear. Mounting evidence suggest that CB1R expression and activation may contribute to pain. Cannabinoid 1 receptor knockout mice (CB1R−/−) generated on a C57Bl/6 background exhibit hypoalgesia in the hotplate assay and formalin test. These findings suggest that Cannabinoid 1 receptor expression mediates the responses to at least some types of painful stimuli. By using this mouse line, we sought to determine if the lack of Cannabinoid 1 receptor unveils a general hypoalgesic phenotype, including protection against the development of neuropathic pain. The acetone test was used to measure cold sensitivity, the electronic von Frey was used to measure mechanical thresholds before and after spared-nerve injury, and analysis of footprint patterns was conducted to determine if motor function is differentially affected after nerve-injury in mice with varying levels of Cannabinoid 1 receptor. Results At baseline, CB1R−/− mice were hypersensitive in the acetone test, and this phenotype was maintained after spared-nerve injury. Using calcium imaging of lumbar dorsal root ganglion (DRG) cultures, a higher percentage of neurons isolated from CB1R−/− mice were menthol sensitive relative to DRG isolated from wild-type (CB1R+/+) mice. Baseline mechanical thresholds did not differ among genotypes, and mechanical hypersensitivity developed similarly in the first two weeks following spared-nerve injury (SNI). At two weeks post-SNI, CB1R−/− mice recovered significantly from mechanical hypersensitivity, while the CB1R+/+ mice did not. Heterozygous knockouts (CB1R+/−) transiently developed cold allodynia only after injury, but recovered mechanical thresholds to a similar extent as the CB1R−/− mice. Sciatic functional indices, which reflect overall nerve health, and alternation coefficients, which indicate uniformity of strides, were not significantly different among genotypes. Conclusion Cold allodynia and significant recovery from spared-nerve injury-induced mechanical hypersensitivity are two novel phenotypes which characterize the global CB1R−/− mice. An increase in transient receptor potential channel of melastatin 8 channel function in DRG neurons may underlie the cold phenotype. Recovery of mechanical thresholds in the CB1R knockouts was independent of motor function. These results indicate that CB1R expression contributes to the development of persistent mechanical hypersensitivity, protects against the development of robust cold allodynia but is not involved in motor impairment following spared-nerve injury in mice.
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Affiliation(s)
- Alexandra Sideris
- Department of Anesthesiology, Perioperative Care and Pain Medicine, NYU Langone Medical Center, NY, USA
| | - Boris Piskoun
- Department of Anesthesiology, Perioperative Care and Pain Medicine, NYU Langone Medical Center, NY, USA
| | - Lori Russo
- Department of Anesthesiology, Perioperative Care and Pain Medicine, NYU Langone Medical Center, NY, USA
| | - Monica Norcini
- Department of Anesthesiology, Perioperative Care and Pain Medicine, NYU Langone Medical Center, NY, USA
| | - Thomas Blanck
- Department of Anesthesiology, Perioperative Care and Pain Medicine, NYU Langone Medical Center, NY, USA Department of Physiology and Neuroscience, NYU Langone Medical Center, NY, USA
| | - Esperanza Recio-Pinto
- Department of Anesthesiology, Perioperative Care and Pain Medicine, NYU Langone Medical Center, NY, USA Department of Biochemistry & Molecular Pharmacology, NYU Langone Medical Center, NY, USA
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Sawynok J, Liu J. Contributions of peripheral, spinal, and supraspinal actions to analgesia. Eur J Pharmacol 2014; 734:114-21. [PMID: 24731877 DOI: 10.1016/j.ejphar.2014.04.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 04/02/2014] [Accepted: 04/03/2014] [Indexed: 02/08/2023]
Abstract
Pain signaling involves several main compartments that can be considered as potential sites for analgesic drug actions. When drugs are given systemically, they can act at spinal, supraspinal and peripheral sites, and several methods have been developed for identifying where they act. These include (1) localized delivery of drugs to specific sites (via intracerebral, intrathecal, and intraplantar injections), (2) systemic delivery of drugs with localized delivery of antagonists for the receptor on which the drug acts or for a system recruited by the drug, (3) use of peripherally restricted analogs, and (4) use of conditional knockout technology to selectively deplete receptors on nociceptors. Delivery of drugs simultaneously to several sites (spinal/supraspinal, peripheral/spinal, and peripheral/supraspinal) reveals "self-synergy" between sites for some agents. Knowledge of peripheral contributions to drug actions is important because of the potential to develop peripherally restricted analgesics (with a diminished side effect profile due to not entering the central nervous system), the potential to deliver drugs peripherally (e.g. topically) to act on sensory nerve endings and adjacent tissue (with a diminished side effect profile due to limited systemic absorption), and the potential to use combinations of topical and oral drug regimens to obtain improved pain relief (without increasing the side effect burden). This review considers methods used for compartmental analysis, and results of such site analysis for several major classes of analgesic drugs that are in current use.
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Affiliation(s)
- Jana Sawynok
- Department of Pharmacology, Dalhousie University, 5850 College Street, P.O. Box 15000, Halifax, Nova Scotia, Canada B3H 4R2.
| | - Jean Liu
- Department of Pharmacology, Dalhousie University, 5850 College Street, P.O. Box 15000, Halifax, Nova Scotia, Canada B3H 4R2
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Savastano LE, Laurito SR, Fitt MR, Rasmussen JA, Gonzalez Polo V, Patterson SI. Sciatic nerve injury: A simple and subtle model for investigating many aspects of nervous system damage and recovery. J Neurosci Methods 2014; 227:166-80. [DOI: 10.1016/j.jneumeth.2014.01.020] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 01/16/2014] [Accepted: 01/20/2014] [Indexed: 02/04/2023]
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Martínez de Albornoz P, Delgado PJ, Forriol F, Maffulli N. Non-surgical therapies for peripheral nerve injury. Br Med Bull 2011; 100:73-100. [PMID: 21429947 DOI: 10.1093/bmb/ldr005] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND Non-surgical approaches have been developed to enhance nerve recovery, which are complementary to surgery and are an adjunct to the reinnervation process. SOURCES OF DATA A search of PubMed, Medline, CINAHL, DH data and Embase databases was performed using the keywords 'peripheral nerve injury' and 'treatment'. AREAS OF CONTROVERSY Most of the conservative therapies are focused to control neuropathic pain after nerve tissue damage. Only physical therapy modalities have been studied in humans and their effectiveness is not proved. GROWING POINTS Many modalities have been experimented with to promote nerve healing and restore function in animal models and in vitro studies. Despite this, none have been actually translated into clinical practice. AREAS TIMELY FOR DEVELOPING RESEARCH The hypotheses proved in animals and in vitro should be translated to human clinical practice.
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Affiliation(s)
- Pilar Martínez de Albornoz
- Department of Trauma and Orthopaedic Surgery, FREMAP Hospital, Ctra de Pozuelo 61, 28220 Majadahonda, Madrid, Spain
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Karst M, Wippermann S. Cannabinoids against pain. Efficacy and strategies to reduce psychoactivity: a clinical perspective. Expert Opin Investig Drugs 2009; 18:125-33. [PMID: 19236260 DOI: 10.1517/13543780802691951] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The clinical use of cannabinoids is currently a topic of interest not exclusively, but most importantly, concerning different areas of pain therapy. One of the major obstacles in developing clinically acceptable compounds is the cannabimimetic side-effect profile of delta-9-tetrahydrocannabinol (THC) and other cannabinoids. This article gives a brief overview of the endocannabinoid system, its components and functions and explains the current approaches to avoiding cannabimimetic side effects by separating them from the therapeutic effects. One of these approaches is the addition of cannabidiol (CBD) as well as the use of preparations suitable for oromucosal application. Also cannabinoids, which primarily stimulate peripheral cannabinoid-1 (CB1) receptors or selectively cannabinoid-2 (CB2) receptors, can further separate analgesic activity from cannabimimetic activity. Local or topical modes of application are another attempt aiming in the same direction. Modulating the endogenous cannabinoid tone (via the inhibition of endocannabinoid-metabolising enzymes) is another strategy. The combination of THC in low, non-psychoactive doses with opioids has a synergistic effect and reduces opioid tolerance effects. Available data from these approaches are summarised and their more and less promising aspects are discussed.
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Affiliation(s)
- Matthias Karst
- Pain Clinic, Hannover Medical School, Department of Anesthesiology, Carl-Neuberg-Street 1, 30625 Hannover, Germany.
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Zhu CZ, Mikusa JP, Fan Y, Hollingsworth PR, Pai M, Chandran P, Daza AV, Yao BB, Dart MJ, Meyer MD, Decker MW, Hsieh GC, Honore P. Peripheral and central sites of action for the non-selective cannabinoid agonist WIN 55,212-2 in a rat model of post-operative pain. Br J Pharmacol 2009; 157:645-55. [PMID: 19371344 DOI: 10.1111/j.1476-5381.2009.00184.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND AND PURPOSE Activation of cannabinoid (CB) receptors decreases nociceptive transmission in inflammatory or neuropathic pain states. However, the effects of CB receptor agonists in post-operative pain remain to be investigated. Here, we characterized the anti-allodynic effects of WIN 55,212-2 (WIN) in a rat model of post-operative pain. EXPERIMENTAL APPROACH WIN 55,212-2 was characterized in radioligand binding and in vitro functional assays at rat and human CB(1) and CB(2) receptors. Analgesic activity and site(s) of action of WIN were assessed in the skin incision-induced post-operative pain model in rats; receptor specificity was investigated using selective CB(1) and CB(2) receptor antagonists. KEY RESULTS WIN 55,212-2 exhibited non-selective affinity and agonist efficacy at human and rat CB(1) versus CB(2) receptors. Systemic administration of WIN decreased injury-induced mechanical allodynia and these effects were reversed by pretreatment with a CB(1) receptor antagonist, but not with a CB(2) receptor antagonist, given by systemic, intrathecal and supraspinal routes. In addition, peripheral administration of both CB(1) and CB(2) antagonists blocked systemic WIN-induced analgesic activity. CONCLUSIONS AND IMPLICATIONS Both CB(1) and CB(2) receptors were involved in the peripheral anti-allodynic effect of systemic WIN in a pre-clinical model of post-operative pain. In contrast, the centrally mediated anti-allodynic activity of systemic WIN is mostly due to the activation of CB(1) but not CB(2) receptors at both the spinal cord and brain levels. However, the increased potency of WIN following i.c.v. administration suggests that its main site of action is at CB(1) receptors in the brain.
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Affiliation(s)
- C Z Zhu
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, IL 60064, USA.
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Recent data on cannabinoids and their pharmacological implications in neuropathic pain. J Med Life 2008; 1:365-75. [PMID: 20108515 PMCID: PMC5654208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/30/2022] Open
Abstract
Natural cannabinoids have been used for centuries for their psychotropic properties, but their possible therapeutic implications in analgesia have been recently documented. The present review intended to make an analysis of the neuroanatomy and physiology of the cannabinoid system (receptors, functions, agents acting on these receptors) and of its implications in neuropathic pain. There were also described the complex phenomena implicated in the generation and maintenance of neuropathic pain, by high lightening the implications of endogenous cannabinoids in this complex of painful conditions. The pharmacological analgesia test proves of cannabinoid implication in neuropathic pain was sustained by many studies presented in this paper. Therapeutic approaches using natural and synthetic cannabinoid receptor agonists were reviewed. Therapeutic perspectives in neuropathic pain might involve the development of new agents that influence the cannabinoid system. Thus, peripheral acting cannabinoid 1 receptors agonists, selective cannabinoid 2 receptor agonists and also modulators of endocannabinoids metabolism might be a way to success in the treatment of this complex entity called neuropathic pain.
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