1
|
Abstract
The endocannabinoids are lipid-derived messengers that play a diversity of regulatory roles in mammalian physiology. Dysfunctions in their activity have been implicated in various disease conditions, attracting attention to the endocannabinoid system as a possible source of therapeutic drugs. This signaling complex has three components: the endogenous ligands, anandamide and 2-arachidonoyl-sn-glycerol (2-AG); a set of enzymes and transporters that generate, eliminate, or modify such ligands; and selective cell surface receptors that mediate their biological actions. We provide an overview of endocannabinoid formation, deactivation, and biotransformation and outline the properties and therapeutic potential of pharmacological agents that interfere with those processes. We describe small-molecule inhibitors that target endocannabinoid-producing enzymes, carrier proteins that transport the endocannabinoids into cells, and intracellular endocannabinoid-metabolizing enzymes. We briefly discuss selected agents that simultaneously interfere with components of the endocannabinoid system and with other functionally related signaling pathways. Expected final online publication date for the Annual Review of Pharmacology and Toxicology, Volume 62 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Collapse
Affiliation(s)
- Daniele Piomelli
- Department of Anatomy and Neurobiology, University of California, Irvine, California 92697, USA; .,Departments of Pharmaceutical Sciences and Biological Chemistry, University of California, Irvine, California 92697, USA
| | - Alex Mabou Tagne
- Department of Anatomy and Neurobiology, University of California, Irvine, California 92697, USA;
| |
Collapse
|
2
|
Inhibitory effect of intrathecally administered AM404, an endocannabinoid reuptake inhibitor, on neuropathic pain in a rat chronic constriction injury model. Pharmacol Rep 2021; 73:820-827. [PMID: 33783763 DOI: 10.1007/s43440-021-00250-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 03/11/2021] [Accepted: 03/15/2021] [Indexed: 12/27/2022]
Abstract
BACKGROUND The endocannabinoid system modulates a wide variety of pain conditions. Systemically administered AM404, an endocannabinoid reuptake inhibitor, exerts antinociceptive effects via activation of the endocannabinoid system. However, the mechanism and site of AM404 action are not fully understood. Here, we explored the effect of AM404 on neuropathic pain at the site of the spinal cord. METHODS Male Sprague-Dawley rats were subjected to chronic constriction injury (CCI) of the sciatic nerve. The effects of intrathecal administration of AM404 on mechanical and cold hyperalgesia were examined using the electronic von Frey test and cold plate test, respectively. Motor coordination was assessed using the rotarod test. To understand the mechanisms underlying the action of AM404, we tested the effects of pretreatment with the cannabinoid type 1 (CB1) receptor antagonist AM251, CB2 receptor antagonist AM630, and transient receptor potential vanilloid type 1 (TRPV1) antagonist capsazepine. RESULTS AM404 attenuated mechanical and cold hyperalgesia with minimal effects on motor coordination. AM251 significantly inhibited the antihyperalgesic action of AM404, whereas capsazepine showed a potentiating effect. CONCLUSIONS These results indicate that AM404 exerts antihyperalgesic effects primarily via CB1, but not CB2, receptor activation at the site of the spinal cord. TRPV1 receptors appear to play a pronociceptive role in CCI rats. The endocannabinoid reuptake inhibitor may be a promising candidate treatment for neuropathic pain.
Collapse
|
3
|
Przybyła GW, Szychowski KA, Gmiński J. Paracetamol - An old drug with new mechanisms of action. Clin Exp Pharmacol Physiol 2021; 48:3-19. [PMID: 32767405 DOI: 10.1111/1440-1681.13392] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 07/09/2020] [Accepted: 08/02/2020] [Indexed: 12/26/2022]
Abstract
Paracetamol (acetaminophen) is the most commonly used over-the-counter (OTC) drug in the world. Despite its popularity and use for many years, the safety of its application and its mechanism of action are still unclear. Currently, it is believed that paracetamol is a multidirectional drug and at least several metabolic pathways are involved in its analgesic and antipyretic action. The mechanism of paracetamol action consists in inhibition of cyclooxygenases (COX-1, COX-2, and COX-3) and involvement in the endocannabinoid system and serotonergic pathways. Additionally, paracetamol influences transient receptor potential (TRP) channels and voltage-gated Kv7 potassium channels and inhibits T-type Cav3.2 calcium channels. It also exerts an impact on L-arginine in the nitric oxide (NO) synthesis pathway. However, not all of these effects have been clearly confirmed. Therefore, the aim of our paper was to summarize the current state of knowledge of the mechanism of paracetamol action with special attention to its safety concerns.
Collapse
Affiliation(s)
| | - Konrad A Szychowski
- Department of Lifestyle Disorders and Regenerative Medicine, University of Information Technology and Management in Rzeszow, Rzeszow, Poland
| | - Jan Gmiński
- Department of Lifestyle Disorders and Regenerative Medicine, University of Information Technology and Management in Rzeszow, Rzeszow, Poland
| |
Collapse
|
4
|
Cifani C, Avagliano C, Micioni Di Bonaventura E, Giusepponi ME, De Caro C, Cristiano C, La Rana G, Botticelli L, Romano A, Calignano A, Gaetani S, Micioni Di Bonaventura MV, Russo R. Modulation of Pain Sensitivity by Chronic Consumption of Highly Palatable Food Followed by Abstinence: Emerging Role of Fatty Acid Amide Hydrolase. Front Pharmacol 2020; 11:266. [PMID: 32231568 PMCID: PMC7086305 DOI: 10.3389/fphar.2020.00266] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 02/24/2020] [Indexed: 01/03/2023] Open
Abstract
There is a strong relationship between palatable diet and pain sensitivity, and the cannabinoid and opioid systems might play an important role in this correlation. The palatable diet used in many animal models of obesity is the cafeteria (CAF) diet, based on human food with high sugar, salt, and fat content. In this study, we investigated whether long-term exposure to a CAF diet could modify pain sensitivity and explored the role of the cannabinergic system in this modification. Male Sprague–Dawley rats were divided into two groups: one fed with standard chow only (CO) and the other with extended access (EA) to a CAF diet. Hot plate and tail flick tests were used to evaluate pain sensitivity. At the end of a 40-day CAF exposure, EA rats showed a significant increase in the pain threshold compared to CO rats, finding probably due to up-regulation of CB1 and mu-opioid receptors. Instead, during abstinence from palatable foods, EA animals showed a significant increase in pain sensibility, which was ameliorated by repeated treatment with a fatty acid amide hydrolase inhibitor, PF-3845 (10 mg/kg, intraperitoneally), every other day for 28 days. Ex vivo analysis of the brains of these rats clearly showed that this effect was mediated by mu-opioid receptors, which were up-regulated following repeated treatment of PF-3845. Our data add to the knowledge about changes in pain perception in obese subjects, revealing a key role of CB1 and mu-opioid receptors and their possible pharmacological crosstalk and reinforcing the need to consider this modulation in planning effective pain management for obese patients.
Collapse
Affiliation(s)
- Carlo Cifani
- School of Pharmacy, Pharmacology Unit, University of Camerino, Camerino, Italy
| | - Carmen Avagliano
- Department of Pharmacy, "Federico II" University of Naples, Naples, Italy
| | | | | | - Carmen De Caro
- Department of Pharmacy, "Federico II" University of Naples, Naples, Italy
| | - Claudia Cristiano
- Department of Pharmacy, "Federico II" University of Naples, Naples, Italy
| | - Giovanna La Rana
- Department of Pharmacy, "Federico II" University of Naples, Naples, Italy
| | - Luca Botticelli
- School of Pharmacy, Pharmacology Unit, University of Camerino, Camerino, Italy
| | - Adele Romano
- Department of Physiology and Pharmacology "V. Erspamer," Sapienza University of Rome, Rome, Italy
| | - Antonio Calignano
- Department of Pharmacy, "Federico II" University of Naples, Naples, Italy
| | - Silvana Gaetani
- Department of Physiology and Pharmacology "V. Erspamer," Sapienza University of Rome, Rome, Italy
| | | | - Roberto Russo
- Department of Pharmacy, "Federico II" University of Naples, Naples, Italy
| |
Collapse
|
5
|
Udoh M, Santiago M, Devenish S, McGregor IS, Connor M. Cannabichromene is a cannabinoid CB 2 receptor agonist. Br J Pharmacol 2019; 176:4537-4547. [PMID: 31368508 DOI: 10.1111/bph.14815] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 06/11/2019] [Accepted: 07/22/2019] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND AND PURPOSE Cannabichromene (CBC) is one of the most abundant phytocannabinoids in Cannabis spp. It has modest antinociceptive and anti-inflammatory effects and potentiates some effects of Δ9 -tetrahydrocannabinol in vivo. How CBC exerts these effects is poorly defined and there is little information about its efficacy at cannabinoid receptors. We sought to determine the functional activity of CBC at cannabinoid CB1 and CB2 receptors. EXPERIMENTAL APPROACH AtT20 cells stably expressing haemagglutinin-tagged human CB1 and CB2 receptors were used. Assays of cellular membrane potential and loss of cell surface receptors were performed. KEY RESULTS CBC activated CB2 but not CB1 receptors to produce hyperpolarization of AtT20 cells. This activation was inhibited by a CB2 receptor antagonist AM630, and sensitive to Pertussis toxin. Application of CBC reduced activation of CB2 , but not CB1 , receptors by subsequent co-application of CP55,940, an efficacious CB1 and CB2 receptor agonist. Continuous CBC application induced loss of cell surface CB2 receptors and desensitization of the CB2 receptor-induced hyperpolarization. CONCLUSIONS AND IMPLICATIONS CBC is a selective CB2 receptor agonist displaying higher efficacy than tetrahydrocannabinol in hyperpolarizing AtT20 cells. CBC can also recruit CB2 receptor regulatory mechanisms. CBC may contribute to the potential therapeutic effectiveness of some cannabis preparations, potentially through CB2 receptor-mediated modulation of inflammation.
Collapse
Affiliation(s)
- Michael Udoh
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Marina Santiago
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Steven Devenish
- Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, University of Sydney, Sydney, NSW, Australia
| | - Iain S McGregor
- Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, University of Sydney, Sydney, NSW, Australia
| | - Mark Connor
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| |
Collapse
|
6
|
Huang HJ, Chen SL, Huang HY, Sun YC, Lee GC, Lee-Chen GJ, Hsieh-Li HM, Su MT. Chronic low dose of AM404 ameliorates the cognitive impairment and pathological features in hyperglycemic 3xTg-AD mice. Psychopharmacology (Berl) 2019; 236:763-773. [PMID: 30426182 PMCID: PMC6469654 DOI: 10.1007/s00213-018-5108-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 11/05/2018] [Indexed: 12/17/2022]
Abstract
RATIONALE Hyperglycemia accelerates the progression of Alzheimer's disease (AD), and GSK3β plays a potential link between AD and hyperglycemia. Therefore, a direct or indirect GSK3β inhibition may have potential to delay the progression of AD. Our previous biochemical assay identified AM404 as a GSK3β inhibitor at high dose (IC50 = 5.353 μM); however, other study suggests that AM404 impaired synaptic plasticity of hippocampus at high dose (10 mg/kg; i.p.). Therefore, the dose and duration of treatment are crucial for the effects of AM404. OBJECTIVE The effects and molecular mechanisms of AM404 at low dose were evaluated from in vitro to in vivo models. METHODS AM404 (0.1-0.5 μM) was tested on tau hyperphosphorylated mouse hippocampal primary cultures treated with Wortmannin (WT) and GF109203X (GFX). Hyperglycemic triple transgenic AD (3×Tg-AD) mice at 6 months old were intraperitoneally injected with AM404 (0.25 mg/kg) for 4 weeks. The spatial learning and memory of mice were measured using the Morris water maze. Mouse brain and serum samples were collected for pathological analyses. RESULTS AM404 (0.5 μM) exhibited significantly augmented neuroprotection toward tau hyperphosphorylation in primary cultures. The chronic systemic administration of AM404 (0.25 mg/kg) attenuated cognitive deficits in hyperglycemic 3×Tg-AD mice. Moreover, chronic low dose of AM404 significantly attenuated Aβ production, tau protein phosphorylation, and inflammation associated with an increase of pS473Akt and pS9-GSK3β. Therefore, AM404 at low dose, not only increased neuroprotection, but also ameliorated cognitive deficit, could be partly by regulating the Akt/GSK3β signaling, which may contribute to downregulation of Aβ, tau hyperphosphorylation, and inflammation in hyperglycemic 3×Tg-AD mice. CONCLUSIONS These results highlight that chronic administration of AM404 at low dose may be through the Akt/GSK3β pathway to ameliorate the impairment in hyperglycemic 3×Tg-AD mice.
Collapse
Affiliation(s)
- Hei-Jen Huang
- Department of Nursing, Mackay Junior College of Medicine, Nursing and Management, Taipei, 11260 Taiwan
| | - Shu-Ling Chen
- 0000 0001 2158 7670grid.412090.eDepartment of Life Science, National Taiwan Normal University, Taipei, 11677 Taiwan
| | - Hsin-Yu Huang
- 0000 0001 2158 7670grid.412090.eDepartment of Life Science, National Taiwan Normal University, Taipei, 11677 Taiwan
| | - Ying-Chieh Sun
- 0000 0001 2158 7670grid.412090.eDepartment of Chemistry, National Taiwan Normal University, Taipei, 11677 Taiwan
| | - Guan-Chiun Lee
- 0000 0001 2158 7670grid.412090.eDepartment of Life Science, National Taiwan Normal University, Taipei, 11677 Taiwan
| | - Guey-Jen Lee-Chen
- 0000 0001 2158 7670grid.412090.eDepartment of Life Science, National Taiwan Normal University, Taipei, 11677 Taiwan
| | - Hsiu Mei Hsieh-Li
- Department of Life Science, National Taiwan Normal University, Taipei, 11677, Taiwan.
| | - Ming-Tsan Su
- Department of Life Science, National Taiwan Normal University, Taipei, 11677, Taiwan.
| |
Collapse
|
7
|
TRPV1 mediates the anticonvulsant effects of acetaminophen in mice. Epilepsy Res 2018; 145:153-159. [DOI: 10.1016/j.eplepsyres.2018.06.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 06/19/2018] [Accepted: 06/30/2018] [Indexed: 12/16/2022]
|
8
|
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.
Collapse
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
| |
Collapse
|
9
|
Enhanced endocannabinoid tone as a potential target of pharmacotherapy. Life Sci 2018; 204:20-45. [PMID: 29729263 DOI: 10.1016/j.lfs.2018.04.054] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/19/2018] [Accepted: 04/28/2018] [Indexed: 12/21/2022]
Abstract
The endocannabinoid system is up-regulated in numerous pathophysiological states such as inflammatory, neurodegenerative, gastrointestinal, metabolic and cardiovascular diseases, pain, and cancer. It has been suggested that this phenomenon primarily serves an autoprotective role in inhibiting disease progression and/or diminishing signs and symptoms. Accordingly, enhancement of endogenous endocannabinoid tone by inhibition of endocannabinoid degradation represents a promising therapeutic approach for the treatment of many diseases. Importantly, this allows for the avoidance of unwanted psychotropic side effects that accompany exogenously administered cannabinoids. The effects of endocannabinoid metabolic pathway modulation are complex, as endocannabinoids can exert their actions directly or via numerous metabolites. The two main strategies for blocking endocannabinoid degradation are inhibition of endocannabinoid-degrading enzymes and inhibition of endocannabinoid cellular uptake. To date, the most investigated compounds are inhibitors of fatty acid amide hydrolase (FAAH), an enzyme that degrades the endocannabinoid anandamide. However, application of FAAH inhibitors (and consequently other endocannabinoid degradation inhibitors) in medicine became questionable due to a lack of therapeutic efficacy in clinical trials and serious adverse effects evoked by one specific compound. In this paper, we discuss multiple pathways of endocannabinoid metabolism, changes in endocannabinoid levels across numerous human diseases and corresponding experimental models, pharmacological strategies for enhancing endocannabinoid tone and potential therapeutic applications including multi-target drugs with additional targets outside of the endocannabinoid system (cyclooxygenase-2, cholinesterase, TRPV1, and PGF2α-EA receptors), and currently used medicines or medicinal herbs that additionally enhance endocannabinoid levels. Ultimately, further clinical and preclinical studies are warranted to develop medicines for enhancing endocannabinoid tone.
Collapse
|
10
|
Saliba SW, Marcotegui AR, Fortwängler E, Ditrich J, Perazzo JC, Muñoz E, de Oliveira ACP, Fiebich BL. AM404, paracetamol metabolite, prevents prostaglandin synthesis in activated microglia by inhibiting COX activity. J Neuroinflammation 2017; 14:246. [PMID: 29237478 PMCID: PMC5729401 DOI: 10.1186/s12974-017-1014-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 11/27/2017] [Indexed: 01/09/2023] Open
Abstract
Background N-arachidonoylphenolamine (AM404), a paracetamol metabolite, is a potent agonist of the transient receptor potential vanilloid type 1 (TRPV1) and low-affinity ligand of the cannabinoid receptor type 1 (CB1). There is evidence that AM404 exerts its pharmacological effects in immune cells. However, the effect of AM404 on the production of inflammatory mediators of the arachidonic acid pathway in activated microglia is still not fully elucidated. Method In the present study, we investigated the effects of AM404 on the eicosanoid production induced by lipopolysaccharide (LPS) in organotypic hippocampal slices culture (OHSC) and primary microglia cultures using Western blot, immunohistochemistry, and ELISA. Results Our results show that AM404 inhibited LPS-mediated prostaglandin E2 (PGE2) production in OHSC, and LPS-stimulated PGE2 release was totally abolished in OHSC if microglial cells were removed. In primary microglia cultures, AM404 led to a significant dose-dependent decrease in the release of PGE2, independent of TRPV1 or CB1 receptors. Moreover, AM404 also inhibited the production of PGD2 and the formation of reactive oxygen species (8-iso-PGF2 alpha) with a reversible reduction of COX-1- and COX-2 activity. Also, it slightly decreased the levels of LPS-induced COX-2 protein, although no effect was observed on LPS-induced mPGES-1 protein synthesis. Conclusions This study provides new significant insights about the potential anti-inflammatory role of AM404 and new mechanisms of action of paracetamol on the modulation of prostaglandin production by activated microglia. Electronic supplementary material The online version of this article (10.1186/s12974-017-1014-3) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Soraya Wilke Saliba
- Department of Psychiatry and Psychotherapy, Laboratory of Translational Psychiatry, Faculty of Medicine, Medical Center - University of Freiburg, Hauptstr. 5, 79104, Freiburg, Germany. .,Faculty of Biology, University of Freiburg, Freiburg, Germany.
| | - Ariel R Marcotegui
- Laboratory of Hepatic Encephalopathy and Portal Hypertension, Center of Applied and Experimental Pathology, University of Buenos Aires, Buenos Aires, Argentina
| | - Ellen Fortwängler
- Department of Psychiatry and Psychotherapy, Laboratory of Translational Psychiatry, Faculty of Medicine, Medical Center - University of Freiburg, Hauptstr. 5, 79104, Freiburg, Germany
| | - Johannes Ditrich
- Department of Psychiatry and Psychotherapy, Laboratory of Translational Psychiatry, Faculty of Medicine, Medical Center - University of Freiburg, Hauptstr. 5, 79104, Freiburg, Germany
| | - Juan Carlos Perazzo
- Laboratory of Hepatic Encephalopathy and Portal Hypertension, Center of Applied and Experimental Pathology, University of Buenos Aires, Buenos Aires, Argentina
| | - Eduardo Muñoz
- Departamento de Biología Celular, Instituto Maimónides de Investigación Biomédica de Córdoba, Hospital Universitario Reina Sofía, Fisiología e Inmunología, Universidad de Córdoba, Córdoba, Spain
| | | | - Bernd L Fiebich
- Department of Psychiatry and Psychotherapy, Laboratory of Translational Psychiatry, Faculty of Medicine, Medical Center - University of Freiburg, Hauptstr. 5, 79104, Freiburg, Germany.
| |
Collapse
|
11
|
Sharma CV, Long JH, Shah S, Rahman J, Perrett D, Ayoub SS, Mehta V. First evidence of the conversion of paracetamol to AM404 in human cerebrospinal fluid. J Pain Res 2017; 10:2703-2709. [PMID: 29238213 PMCID: PMC5716395 DOI: 10.2147/jpr.s143500] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Paracetamol is arguably the most commonly used analgesic and antipyretic drug worldwide, however its mechanism of action is still not fully established. It has been shown to exert effects through multiple pathways, some actions suggested to be mediated via N-arachidonoylphenolamine (AM404). AM404, formed through conjugation of paracetamol-derived p-aminophenol with arachidonic acid in the brain, is an activator of the capsaicin receptor, TRPV1, and inhibits the reuptake of the endocannabinoid, anandamide, into postsynaptic neurons, as well as inhibiting synthesis of PGE2 by COX-2. However, the presence of AM404 in the central nervous system following administration of paracetamol has not yet been demonstrated in humans. Cerebrospinal fluid (CSF) and blood were collected from 26 adult male patients between 10 and 211 minutes following intravenous administration of 1 g of paracetamol. Paracetamol was measured by high-performance liquid chromatography with UV detection. AM404 was measured by liquid chromatography-tandem mass spectrometry. AM404 was detected in 17 of the 26 evaluable CSF samples at 5–40 nmol⋅L−1. Paracetamol was measurable in CSF within 10 minutes, with a maximum measured concentration of 60 μmol⋅L−1 at 206 minutes. This study is the first to report on the presence of AM404 in human CSF following paracetamol administration. This may represent an important finding in our understanding of paracetamol’s mechanism of action, although measured concentrations were far below the previously documented IC50 for this metabolite.
Collapse
Affiliation(s)
- Chhaya V Sharma
- Pain & Anaesthesia Research Centre, St Bartholomew's and The Royal London Hospitals, Barts Health NHS Trust, London, UK
| | - Jamie H Long
- Barts & The London School of Medicine, Queen Mary University of London, London, UK
| | - Seema Shah
- Pain & Anaesthesia Research Centre, St Bartholomew's and The Royal London Hospitals, Barts Health NHS Trust, London, UK
| | - Junia Rahman
- Pain & Anaesthesia Research Centre, St Bartholomew's and The Royal London Hospitals, Barts Health NHS Trust, London, UK
| | - David Perrett
- BioAnalytical Science, Barts & The London School of Medicine, Queen Mary University of London, London, UK
| | - Samir S Ayoub
- School of Health, Sport and Bioscience, Medicines Research Group, University of East London, London, UK
| | - Vivek Mehta
- Pain & Anaesthesia Research Centre, St Bartholomew's and The Royal London Hospitals, Barts Health NHS Trust, London, UK
| |
Collapse
|
12
|
Acetaminophen Relieves Inflammatory Pain through CB 1 Cannabinoid Receptors in the Rostral Ventromedial Medulla. J Neurosci 2017; 38:322-334. [PMID: 29167401 DOI: 10.1523/jneurosci.1945-17.2017] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Revised: 10/27/2017] [Accepted: 11/14/2017] [Indexed: 12/30/2022] Open
Abstract
Acetaminophen (paracetamol) is a widely used analgesic and antipyretic drug with only incompletely understood mechanisms of action. Previous work, using models of acute nociceptive pain, indicated that analgesia by acetaminophen involves an indirect activation of CB1 receptors by the acetaminophen metabolite and endocannabinoid reuptake inhibitor AM 404. However, the contribution of the cannabinoid system to antihyperalgesia against inflammatory pain, the main indication of acetaminophen, and the precise site of the relevant CB1 receptors have remained elusive. Here, we analyzed acetaminophen analgesia in mice of either sex with inflammatory pain and found that acetaminophen exerted a dose-dependent antihyperalgesic action, which was mimicked by intrathecally injected AM 404. Both compounds lost their antihyperalgesic activity in CB1-/- mice, confirming the involvement of the cannabinoid system. Consistent with a mechanism downstream of proinflammatory prostaglandin formation, acetaminophen also reversed hyperalgesia induced by intrathecal prostaglandin E2 To distinguish between a peripheral/spinal and a supraspinal action, we administered acetaminophen and AM 404 to hoxB8-CB1-/- mice, which lack CB1 receptors from the peripheral nervous system and the spinal cord. These mice exhibited unchanged antihyperalgesia indicating a supraspinal site of action. Accordingly, local injection of the CB1 receptor antagonist rimonabant into the rostral ventromedial medulla blocked acetaminophen-induced antihyperalgesia, while local rostral ventromedial medulla injection of AM 404 reduced hyperalgesia in wild-type mice but not in CB1-/- mice. Our results indicate that the cannabinoid system contributes not only to acetaminophen analgesia against acute pain but also against inflammatory pain, and suggest that the relevant CB1 receptors reside in the rostral ventromedial medulla.SIGNIFICANCE STATEMENT Acetaminophen is a widely used analgesic drug with multiple but only incompletely understood mechanisms of action, including a facilitation of endogenous cannabinoid signaling via one of its metabolites. Our present data indicate that enhanced cannabinoid signaling is also responsible for the analgesic effects of acetaminophen against inflammatory pain. Local injections of the acetaminophen metabolite AM 404 and of cannabinoid receptor antagonists as well as data from tissue-specific CB1 receptor-deficient mice suggest the rostral ventromedial medulla as an important site of the cannabinoid-mediated analgesia by acetaminophen.
Collapse
|
13
|
Interactions between the Kynurenine and the Endocannabinoid System with Special Emphasis on Migraine. Int J Mol Sci 2017; 18:ijms18081617. [PMID: 28758944 PMCID: PMC5578009 DOI: 10.3390/ijms18081617] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 07/18/2017] [Accepted: 07/21/2017] [Indexed: 12/15/2022] Open
Abstract
Both the kynurenine and the endocannabinoid systems are involved in several neurological disorders, such as migraine and there are increasing number of reports demonstrating that there are interactions of two systems. Although their cooperation has not yet been implicated in migraine, there are reports suggesting this possibility. Additionally, the individual role of the endocannabinoid and kynurenine system in migraine is reviewed here first, focusing on endocannabinoids, kynurenine metabolites, in particular kynurenic acid. Finally, the function of NMDA and cannabinoid receptors in the trigeminal system-which has a crucial role in the pathomechanisms of migraine-will also be discussed. The interaction of the endocannabinoid and kynurenine system has been demonstrated to be therapeutically relevant in a number of pathological conditions, such as cannabis addiction, psychosis, schizophrenia and epilepsy. Accordingly, the cross-talk of these two systems may imply potential mechanisms related to migraine, and may offer new approaches to manage the treatment of this neurological disorder.
Collapse
|
14
|
Adamson Barnes NS, Mitchell VA, Kazantzis NP, Vaughan CW. Actions of the dual FAAH/MAGL inhibitor JZL195 in a murine neuropathic pain model. Br J Pharmacol 2015; 173:77-87. [PMID: 26398331 DOI: 10.1111/bph.13337] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 08/18/2015] [Accepted: 09/15/2015] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND AND PURPOSE While cannabinoids have been proposed as a potential treatment for neuropathic pain, they have limitations. Cannabinoid receptor agonists have good efficacy in animal models of neuropathic pain; they have a poor therapeutic window. Conversely, selective fatty acid amide hydrolase (FAAH) inhibitors that enhance the endocannabinoid system have a better therapeutic window, but lesser efficacy. We examined whether JZL195, a dual inhibitor of FAAH and monacylglycerol lipase (MAGL), could overcome these limitations. EXPERIMENTAL APPROACH C57BL/6 mice underwent the chronic constriction injury (CCI) model of neuropathic pain. Mechanical and cold allodynia, plus cannabinoid side effects, were assessed in response to systemic drug application. KEY RESULTS JZL195 and the cannabinoid receptor agonist WIN55212 produced dose-dependent reductions in CCI-induced mechanical and cold allodynia, plus side effects including motor incoordination, catalepsy and sedation. JZL195 reduced allodynia with an ED50 at least four times less than that at which it produced side effects. By contrast, WIN55212 reduced allodynia and produce side effects with similar ED50s. The maximal anti-allodynic effect of JZL195 was greater than that produced by selective FAAH, or MAGL inhibitors. The JZL195-induced anti-allodynia was maintained during repeated treatment. CONCLUSIONS AND IMPLICATIONS These findings suggest that JZL195 has greater anti-allodynic efficacy than selective FAAH, or MAGL inhibitors, plus a greater therapeutic window than a cannabinoid receptor agonist. Thus, dual FAAH/MAGL inhibition may have greater potential in alleviating neuropathic pain, compared with selective FAAH and MAGL inhibitors, or cannabinoid receptor agonists.
Collapse
Affiliation(s)
- Nicholas S Adamson Barnes
- Pain Management Research Institute, Kolling Institute of Medical Research, Northern Clinical School, University of Sydney at Royal North Shore Hospital, NSW, Australia
| | - Vanessa A Mitchell
- Pain Management Research Institute, Kolling Institute of Medical Research, Northern Clinical School, University of Sydney at Royal North Shore Hospital, NSW, Australia
| | - Nicholas P Kazantzis
- Pain Management Research Institute, Kolling Institute of Medical Research, Northern Clinical School, University of Sydney at Royal North Shore Hospital, NSW, Australia
| | - Christopher W Vaughan
- Pain Management Research Institute, Kolling Institute of Medical Research, Northern Clinical School, University of Sydney at Royal North Shore Hospital, NSW, Australia
| |
Collapse
|
15
|
Bosier B, Doyen PJ, Brolet A, Muccioli GG, Ahmed E, Desmet N, Hermans E, Deumens R. Inhibition of the regulator of G protein signalling RGS4 in the spinal cord decreases neuropathic hyperalgesia and restores cannabinoid CB1 receptor signalling. Br J Pharmacol 2015; 172:5333-46. [PMID: 26478461 PMCID: PMC5341217 DOI: 10.1111/bph.13324] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 07/24/2015] [Accepted: 09/04/2015] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND AND PURPOSE Regulators of G protein signalling (RGS) are major determinants of metabotropic receptor activity, reducing the lifespan of the GTP-bound state of G proteins. Because the reduced potency of analgesic agents in neuropathic pain may reflect alterations in RGS, we assessed the effects of CCG 63802, a specific RGS4 inhibitor, on pain hypersensitivity and signalling through cannabinoid receptors, in a model of neuropathic pain. EXPERIMENTAL APPROACH The partial sciatic nerve ligation (PSNL) model in male Sprague Dawley rats was used to measure paw withdrawal thresholds to mechanical (von Frey hairs) or thermal (Hargreaves method) stimuli, during and after intrathecal injection of CCG 63802. HEK293 cells expressing CB1 receptors and conditional expression of RGS4 were used to correlate cAMP production and ERK phosphorylation with receptor activation and RGS4 action. KEY RESULTS Treatment of PSNL rats with CCG 63802, twice daily for 7 days after nerve injury, attenuated thermal hyperalgesia during treatment. Spinal levels of anandamide were higher in PSNL animals, irrespective of the treatment. Although expression of CB1 receptors was unaffected, HU210-induced CB1 receptor signalling was inhibited in PSNL rats and restored after intrathecal CCG 63802. In transfected HEK cells expressing CB1 receptors and RGS4, inhibition of cAMP production, a downstream effect of CB1 receptor signalling, was blunted after RGS4 overexpression. RGS4 expression also attenuated the CB1 receptor-controlled activation of ERK1/2. CONCLUSIONS AND IMPLICATIONS Inhibition of spinal RGS4 restored endogenous analgesic signalling pathways and mitigated neuropathic pain. Signalling through CB1 receptors may be involved in this beneficial effect.
Collapse
Affiliation(s)
- Barbara Bosier
- Neuropharmacology Group, Institute of NeuroscienceUniversité catholique de LouvainBrusselsBelgium
| | - Pierre J. Doyen
- Neuropharmacology Group, Institute of NeuroscienceUniversité catholique de LouvainBrusselsBelgium
| | - Amandine Brolet
- Neuropharmacology Group, Institute of NeuroscienceUniversité catholique de LouvainBrusselsBelgium
| | - Giulio G. Muccioli
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research InstituteUniversité catholique de LouvainBrusselsBelgium
| | - Eman Ahmed
- Neuropharmacology Group, Institute of NeuroscienceUniversité catholique de LouvainBrusselsBelgium
- Department of Clinical PharmacologyFaculty of Medicine, Suez Canal UniversityIsmailiaEgypt
| | - Nathalie Desmet
- Neuropharmacology Group, Institute of NeuroscienceUniversité catholique de LouvainBrusselsBelgium
| | - Emmanuel Hermans
- Neuropharmacology Group, Institute of NeuroscienceUniversité catholique de LouvainBrusselsBelgium
| | - Ronald Deumens
- Neuropharmacology Group, Institute of NeuroscienceUniversité catholique de LouvainBrusselsBelgium
| |
Collapse
|
16
|
The Potential of Inhibitors of Endocannabinoid Metabolism for Drug Development: A Critical Review. Handb Exp Pharmacol 2015; 231:95-128. [PMID: 26408159 DOI: 10.1007/978-3-319-20825-1_4] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The endocannabinoids anandamide and 2-arachidonoylglycerol are metabolised by both hydrolytic enzymes (primarily fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MGL)) and oxygenating enzymes (e.g. cyclooxygenase-2, COX-2). In the present article, the in vivo data for compounds inhibiting endocannabinoid metabolism have been reviewed, focussing on inflammation and pain. Potential reasons for the failure of an FAAH inhibitor in a clinical trial in patients with osteoarthritic pain are discussed. It is concluded that there is a continued potential for compounds inhibiting endocannabinoid metabolism in terms of drug development, but that it is wise not to be unrealistic in terms of expectations of success.
Collapse
|
17
|
Caballero FJ, Soler-Torronteras R, Lara-Chica M, García V, Fiebich BL, Muñoz E, Calzado MA. AM404 inhibits NFAT and NF-κB signaling pathways and impairs migration and invasiveness of neuroblastoma cells. Eur J Pharmacol 2014; 746:221-32. [PMID: 25460026 DOI: 10.1016/j.ejphar.2014.11.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 11/14/2014] [Accepted: 11/17/2014] [Indexed: 01/03/2023]
Abstract
N-Arachidonoylphenolamine (AM404), a paracetamol lipid metabolite, is a modulator of the endocannabinoid system endowed with pleiotropic activities. AM404 is a dual agonist of the Transient Receptor Potential Vanilloid type 1 (TRPV1) and the Cannabinoid Receptor type 1 (CB₁) and inhibits anandamide (AEA) transport and degradation. In addition, it has been shown that AM404 also exerts biological activities through TRPV1- and CB₁ -independent pathways. In the present study we have investigated the effect of AM404 in the NFAT and NF-κB signaling pathways in SK-N-SH neuroblastoma cells. AM404 inhibited NFAT transcriptional activity through a CB₁- and TRPV1-independent mechanism. Moreover, AM404 inhibited both the expression of COX-2 at transcriptional and post-transcriptional levels and the synthesis of PGE₂. AM404 also inhibited NF-κB activation induced by PMA/Ionomycin in SK-N-SH cells by targeting IKKβ phosphorylation and activation. We found that Cot/Tlp-2 induced NFAT and COX-2 transcriptional activities were inhibited by AM404. NFAT inhibition paralleled with the ability of AM404 to inhibit MMP-1, -3 and -7 expression, cell migration and invasion in a cell-type specific dependent manner. Taken together, these data reveal that paracetamol, the precursor of AM404, can be explored not only as an antipyretic and painkiller drug but also as a co-adjuvant therapy in inflammatory and cancer diseases.
Collapse
Affiliation(s)
- Francisco J Caballero
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC)/ Hospital Universitario Reina Sofía/ Universidad de Córdoba, Córdoba, Spain
| | - Rafael Soler-Torronteras
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC)/ Hospital Universitario Reina Sofía/ Universidad de Córdoba, Córdoba, Spain
| | - Maribel Lara-Chica
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC)/ Hospital Universitario Reina Sofía/ Universidad de Córdoba, Córdoba, Spain
| | - Victor García
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC)/ Hospital Universitario Reina Sofía/ Universidad de Córdoba, Córdoba, Spain
| | - Bernd L Fiebich
- Department of Psychiatry, University of Freiburg Medical School, Freiburg, Germany
| | - Eduardo Muñoz
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC)/ Hospital Universitario Reina Sofía/ Universidad de Córdoba, Córdoba, Spain.
| | - Marco A Calzado
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC)/ Hospital Universitario Reina Sofía/ Universidad de Córdoba, Córdoba, Spain.
| |
Collapse
|
18
|
Ignatowska-Jankowska BM, Ghosh S, Crowe MS, Kinsey SG, Niphakis MJ, Abdullah RA, Tao Q, O' Neal ST, Walentiny DM, Wiley JL, Cravatt BF, Lichtman AH. In vivo characterization of the highly selective monoacylglycerol lipase inhibitor KML29: antinociceptive activity without cannabimimetic side effects. Br J Pharmacol 2014; 171:1392-407. [PMID: 23848221 PMCID: PMC3954480 DOI: 10.1111/bph.12298] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 06/14/2013] [Accepted: 07/08/2013] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND PURPOSE Since monoacylglycerol lipase (MAGL) has been firmly established as the predominant catabolic enzyme of the endocannabinoid 2-arachidonoylglycerol (2-AG), a great need has emerged for the development of highly selective MAGL inhibitors. Here, we tested the in vivo effects of one such compound, KML29 (1,1,1,3,3,3-hexafluoropropan-2-yl 4-(bis(benzo[d][1,3]dioxol-5-yl)(hydroxy)methyl)piperidine-1-carboxylate). EXPERIMENTAL APPROACH In the present study, we tested KML29 in murine inflammatory (i.e. carrageenan) and sciatic nerve injury pain models, as well as the diclofenac-induced gastric haemorrhage model. KML29 was also evaluated for cannabimimetic effects, including measurements of locomotor activity, body temperature, catalepsy, and cannabinoid interoceptive effects in the drug discrimination paradigm. KEY RESULTS KML29 attenuated carrageenan-induced paw oedema and completely reversed carrageenan-induced mechanical allodynia. These effects underwent tolerance after repeated administration of high-dose KML29, which were accompanied by cannabinoid receptor 1 (CB1 ) receptor desensitization. Acute or repeated KML29 administration increased 2-AG levels and concomitantly reduced arachidonic acid levels, but without elevating anandamide (AEA) levels in the whole brain. Furthermore, KML29 partially reversed allodynia in the sciatic nerve injury model and completely prevented diclofenac-induced gastric haemorrhages. CB1 and CB2 receptors played differential roles in these pharmacological effects of KML29. In contrast, KML29 did not elicit cannabimimetic effects, including catalepsy, hypothermia and hypomotility. Although KML29 did not substitute for Δ(9) -tetrahydrocannabinol (THC) in C57BL/6J mice, it fully and dose-dependantly substituted for AEA in fatty acid amide hydrolase (FAAH) (-/-) mice, consistent with previous work showing that dual FAAH and MAGL inhibition produces THC-like subjective effects. CONCLUSIONS AND IMPLICATIONS These results indicate that KML29, a highly selective MAGL inhibitor, reduces inflammatory and neuropathic nociceptive behaviour without occurrence of cannabimimetic side effects. LINKED ARTICLES This article is part of a themed section on Cannabinoids 2013. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-6.
Collapse
Affiliation(s)
| | - S Ghosh
- Department of Pharmacology and Toxicology, Virginia Commonwealth UniversityRichmond, VA, USA
| | - M S Crowe
- Department of Psychology, West Virginia UniversityMorgantown, WV, USA
| | - S G Kinsey
- Department of Psychology, West Virginia UniversityMorgantown, WV, USA
| | - M J Niphakis
- The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research InstituteLa Jolla, CA, USA
| | - R A Abdullah
- Department of Pharmacology and Toxicology, Virginia Commonwealth UniversityRichmond, VA, USA
| | - Q Tao
- Department of Pharmacology and Toxicology, Virginia Commonwealth UniversityRichmond, VA, USA
| | - S T O' Neal
- Department of Pharmacology and Toxicology, Virginia Commonwealth UniversityRichmond, VA, USA
| | - D M Walentiny
- Department of Pharmacology and Toxicology, Virginia Commonwealth UniversityRichmond, VA, USA
| | - J L Wiley
- Research Triangle InstituteResearch Triangle Park, NC, USA
| | - B F Cravatt
- The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research InstituteLa Jolla, CA, USA
| | - A H Lichtman
- Department of Pharmacology and Toxicology, Virginia Commonwealth UniversityRichmond, VA, USA
| |
Collapse
|
19
|
Khasabova IA, Holman M, Morse T, Burlakova N, Coicou L, Harding-Rose C, Simone DA, Seybold VS. Increased anandamide uptake by sensory neurons contributes to hyperalgesia in a model of cancer pain. Neurobiol Dis 2013; 58:19-28. [PMID: 23644187 DOI: 10.1016/j.nbd.2013.04.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 04/19/2013] [Accepted: 04/24/2013] [Indexed: 11/26/2022] Open
Abstract
Opioids do not effectively manage pain in many patients with advanced cancer. Because anandamide (AEA) activation of cannabinoid type-1 receptors (CB1R) on nociceptors reduces nociception, manipulation of AEA metabolism in the periphery may be an effective alternative or adjuvant therapy in the management of cancer pain. AEA is hydrolyzed by the intracellular enzyme fatty acid amide hydrolase (FAAH), and this enzyme activity contributes to uptake of AEA into neurons and to reduction of AEA available to activate CB1R. We used an in vitro preparation of adult murine dorsal root ganglion (DRG) neurons co-cultured with fibrosarcoma cells to investigate how tumors alter the uptake of AEA into neurons. Evidence that the uptake of [(3)H]AEA into dissociated DRG cells in the co-culture model mimicked the increase in uptake that occurred in DRG cells from tumor-bearing mice supported the utility of the in vitro model to study AEA uptake. Results with the fluorescent AEA analog CAY10455 confirmed that an increase in uptake in the co-culture model occurred in neurons. One factor that contributed to the increase in [(3)H]AEA uptake was an increase in total cellular cholesterol in the cancer condition. Treatment with the FAAH inhibitor URB597 reduced CAY10455 uptake in the co-culture model to the level observed in DRG neurons maintained in the control condition (i.e., in the absence of fibrosarcoma cells), and this effect was paralleled by OMDM-1, an inhibitor of AEA uptake, at a concentration that had no effect on FAAH activity. Maximally effective concentrations of the two drugs together produced a greater reduction than was observed with each drug alone. Treatment with BMS309403, which competes for AEA binding to fatty acid binding protein-5, mimicked the effect of OMDM-1 in vitro. Local injection of OMDM-1 reduced hyperalgesia in vivo in mice with unilateral tumors in and around the calcaneous bone. Intraplantar injection of OMDM-1 (5μg) into the tumor-bearing paw reduced mechanical hyperalgesia through a CB1R-dependent mechanism and also reduced a spontaneous nocifensive behavior. The same dose reduced withdrawal responses evoked by suprathreshold mechanical stimuli in naive mice. These data support the conclusion that OMDM-1 inhibits AEA uptake by a mechanism that is independent of inhibition of FAAH and provide a rationale for the development of peripherally restricted drugs that decrease AEA uptake for the management of cancer pain.
Collapse
Affiliation(s)
- Iryna A Khasabova
- Department of Diagnostic and Biological Sciences, Dental School, University of Minnesota, Minneapolis, MN, USA
| | | | | | | | | | | | | | | |
Collapse
|
20
|
|
21
|
Fowler CJ. Transport of endocannabinoids across the plasma membrane and within the cell. FEBS J 2013; 280:1895-904. [PMID: 23441874 DOI: 10.1111/febs.12212] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 01/08/2013] [Accepted: 02/12/2013] [Indexed: 11/29/2022]
Abstract
Endocannabinoids are readily accumulated from the extracellular space by cells. Although their uptake properties have the appearance of a process of facilitated diffusion, it is by no means clear as to whether there is a plasma membrane transporter dedicated to this task. Intracellular carrier proteins that shuttle the endocannabinoid anandamide from the plasma membrane to its intracellular targets such as the metabolic enzyme, fatty acid amide hydrolase, have been identified. These include proteins with other primary functions, such as fatty-acid-binding proteins and heat shock protein 70, and possibly a fatty acid amide hydrolase-like anandamide transporter protein. Thus, anandamide uptake can be adequately described as a diffusion process across the plasma membrane followed by intracellular carrier-mediated transport to effector molecules, catabolic enzymes and sequestration sites, although it is recognized that different cells are likely to utilize different mechanisms of endocannabinoid transport depending upon the utility of the endocannabinoid for the cell in question.
Collapse
Affiliation(s)
- Christopher J Fowler
- Department of Pharmacology and Clinical Neuroscience, Umeå University, Umeå, Sweden.
| |
Collapse
|
22
|
Russo R, D'Agostino G, Mattace Raso G, Avagliano C, Cristiano C, Meli R, Calignano A. Central administration of oxytocin reduces hyperalgesia in mice: implication for cannabinoid and opioid systems. Peptides 2012; 38:81-8. [PMID: 22917880 DOI: 10.1016/j.peptides.2012.08.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 08/03/2012] [Accepted: 08/03/2012] [Indexed: 11/21/2022]
Abstract
The neuropeptide oxytocin (OXT) contributes to the regulation of diverse cognitive and physiological functions including nociception. Indeed, OXT has been reported to be analgesic when administered directly into the brain, the spinal cord, or systemically. Although many authors have reported the analgesic effects of OXT, its mechanism has not been well elucidated. Recently, it has been also hypothesize that OXT, increasing intracellular concentration of calcium, could regulate the production of mediators, like endocannabinoids (eCB). It has been well documented that eCB are able to suppress pain pathways. The present study investigates the effect of OXT in paw carrageenan-induced pain. Intracerebroventricular (icv) administration of OXT, but neither intraperitoneal nor intraplantar route, induces an antihyperalgesic effect increasing paw withdrawal latency to mechanical or thermal stimuli. Our results clearly demonstrate that 3 and 6h following carrageenan challenge, central administration of OXT (30 ng/mouse) shows a significant antihyperalgesic activity. Moreover, for the first time, we demonstrate that CB1 receptor plays a key role in the antihyperalgesic effect of OXT. In fact our results show CB1 antagonist, but not the specific CB2 antagonist reduce OXT-induced antihyperalgesic effect. In addition, our data show that central OXT administration is able to reduce carrageenan-induced hyperalgesia but does not modify carrageenan-induced paw edema. Finally, using opioid antagonists we confirm an important role of opioid receptors. In conclusion, our experiments suggest that central administration of OXT reduces hyperalgesia induced by intraplantar injection of carrageenan, and this effect may work via cannabinoid and opioid systems.
Collapse
MESH Headings
- Analgesics, Non-Narcotic/pharmacology
- Animals
- Carrageenan/adverse effects
- Cyclooxygenase 2/metabolism
- Dose-Response Relationship, Drug
- Edema/chemically induced
- Edema/drug therapy
- Hyperalgesia/chemically induced
- Hyperalgesia/drug therapy
- Injections, Intraventricular
- Male
- Mice
- Motor Activity/drug effects
- Naloxone/pharmacology
- Narcotic Antagonists/pharmacology
- Nitric Oxide Synthase Type I/metabolism
- Nitric Oxide Synthase Type II/metabolism
- Oxytocin/administration & dosage
- Oxytocin/pharmacology
- Pain/chemically induced
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB2/antagonists & inhibitors
- Receptor, Cannabinoid, CB2/metabolism
- Receptors, Opioid/metabolism
- Receptors, Oxytocin/metabolism
- Spinal Cord/drug effects
- Spinal Cord/enzymology
Collapse
Affiliation(s)
- R Russo
- Department of Experimental Pharmacology, University of Naples Federico II, Naples, Italy
| | | | | | | | | | | | | |
Collapse
|
23
|
Chicca A, Marazzi J, Nicolussi S, Gertsch J. Evidence for bidirectional endocannabinoid transport across cell membranes. J Biol Chem 2012; 287:34660-82. [PMID: 22879589 DOI: 10.1074/jbc.m112.373241] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Despite extensive research on the trafficking of anandamide (AEA) across cell membranes, little is known about the membrane transport of other endocannabinoids, such as 2-arachidonoylglycerol (2-AG). Previous studies have provided data both in favor and against a cell membrane carrier-mediated transport of endocannabinoids, using different methodological approaches. Because AEA and 2-AG undergo rapid and almost complete intracellular hydrolysis, we employed a combination of radioligand assays and absolute quantification of cellular and extracellular endocannabinoid levels. In human U937 leukemia cells, 100 nm AEA and 1 μm 2-AG were taken up through a fast and saturable process, reaching a plateau after 5 min. Employing differential pharmacological blockage of endocannabinoid uptake, breakdown, and interaction with intracellular binding proteins, we show that eicosanoid endocannabinoids harboring an arachidonoyl chain compete for a common membrane target that regulates their transport, whereas other N-acylethanolamines did not interfere with AEA and 2-AG uptake. By combining fatty acid amide hydrolase or monoacyl glycerol lipase inhibitors with hydrolase-inactive concentrations of the AEA transport inhibitors UCM707 (1 μm) and OMDM-2 (5 μm), a functional synergism on cellular AEA and 2-AG uptake was observed. Intriguingly, structurally unrelated AEA uptake inhibitors also blocked the cellular release of AEA and 2-AG. We show, for the first time, that UCM707 and OMDM-2 inhibit the bidirectional movement of AEA and 2-AG across cell membranes. Our findings suggest that a putative endocannabinoid cell membrane transporter controls the cellular AEA and 2-AG trafficking and metabolism.
Collapse
Affiliation(s)
- Andrea Chicca
- Institute of Biochemistry and Molecular Medicine, National Center of Competence in Research TransCure, University of Bern, CH-3012 Bern, Switzerland
| | | | | | | |
Collapse
|
24
|
Farghaly HSM, Abdel-Zaher AO, Mostafa MG, Kotb HI. Comparative evaluation of the effect of tricyclic antidepressants on inducible nitric oxide synthase expression in neuropathic pain model. Nitric Oxide 2012; 27:88-94. [DOI: 10.1016/j.niox.2012.05.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2012] [Revised: 04/24/2012] [Accepted: 05/07/2012] [Indexed: 12/23/2022]
|
25
|
Alcohol and cannabis use and mortality in people with schizophrenia and related psychotic disorders. J Psychiatr Res 2012; 46:987-93. [PMID: 22595870 PMCID: PMC3392453 DOI: 10.1016/j.jpsychires.2012.04.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 04/20/2012] [Accepted: 04/23/2012] [Indexed: 11/22/2022]
Abstract
The impact of co-morbid substance use on mortality is not well studied in psychotic disorders. The objective of this study was to examine the impact of substance use on mortality in people with psychotic disorders and alcohol and/or drug use. We examined the rate of substance use and the risk of substance use on mortality risk over a 4-10 year period in 762 people with psychotic disorders. Deceased patients were identified from the Social Security Death Index and the Maryland Division of Vital Records. Substance use was defined as regular and heavy use or abuse or dependence. Seventy seven percent had co-morbid lifetime substance use, with co-morbid cannabis and alcohol use occurring most commonly. Out of 762 subjects, 62 died during follow up. In a Cox model, predicted mortality risk was higher in age group 35-55 compared to <35 years and in males, but reduced in cannabis users. Overall five- (3.1% vs 7.5%) and ten-year mortality risk (5.5% vs. 13.6%) was lower in cannabis users than in non-users with psychotic disorders (p = 0.005) in a survival model. Alcohol use was not predictive of mortality. We observed a lower mortality risk in cannabis-using psychotic disorder patients compared to cannabis non-users despite subjects having similar symptoms and treatments. Future research is warranted to replicate these findings and to shed light on the anti-inflammatory properties of the endocannabinoid system and its role in decreased mortality in people with psychotic disorders.
Collapse
|
26
|
Hegyi Z, Holló K, Kis G, Mackie K, Antal M. Differential distribution of diacylglycerol lipase-alpha and N-acylphosphatidylethanolamine-specific phospholipase d immunoreactivity in the superficial spinal dorsal horn of rats. Glia 2012; 60:1316-29. [PMID: 22573306 DOI: 10.1002/glia.22351] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Accepted: 04/20/2012] [Indexed: 11/05/2022]
Abstract
It is generally accepted that the endocannabinoid system plays important roles in spinal pain processing. Although it is documented that cannabinoid-1 receptors are strongly expressed in the superficial spinal dorsal horn, the cellular distribution of enzymes that can synthesize endocannabinoid ligands is less well studied. Thus, using immunocytochemical methods at the light and electron microscopic levels, we investigated the distribution of diacylglycerol lipase-alpha (DGL-α) and N-acylphosphatidylethanolamine-specific phospholipase D (NAPE-PLD), enzymes synthesizing the endocannabinoid ligands, 2-arachidonoylglycerol (2-AG) and anandamide, respectively. Positive labeling was revealed only occasionally in axon terminals, but dendrites displayed strong immunoreactivity for both enzymes. However, the dendritic localization of DGL-α and NAPE-PLD showed a remarkably different distribution. DGL-α immunolabeling in dentrites was always revealed at membrane compartments in close vicinity to synapses. In contrast to this, dendritic NAPE-PLD labeling was never observed in association with synaptic contacts. In addition to dendrites, a substantial proportion of astrocytic (immunoreactive for GFAP) and microglial (immunoreactive for CD11b) profiles were also immunolabeled for both DGL-α and NAPE-PLD. Glial processes immunostained for DGL-α were frequently found near to synapses in which the postsynaptic dendrite was immunoreactive for DGL-α, whereas NAPE-PLD immunoreactivity on glial profiles at the vicinity of synapses was only occasionally observed. Our results suggest that both neurons and glial cells can synthesize and release 2-AG and anandamide in the superficial spinal dorsal horn. The 2-AG can primarily be released by postsynaptic dendrites and glial processes adjacent to synapses, whereas anandamide can predominantly be released from nonsynaptic dendritic and glial compartments.
Collapse
Affiliation(s)
- Zoltán Hegyi
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary
| | | | | | | | | |
Collapse
|
27
|
Fowler CJ. Anandamide uptake explained? Trends Pharmacol Sci 2012; 33:181-5. [DOI: 10.1016/j.tips.2012.01.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 01/03/2012] [Accepted: 01/04/2012] [Indexed: 12/23/2022]
|
28
|
Gamaleddin I, Guranda M, Goldberg SR, Le Foll B. The selective anandamide transport inhibitor VDM11 attenuates reinstatement of nicotine seeking behaviour, but does not affect nicotine intake. Br J Pharmacol 2012; 164:1652-60. [PMID: 21501143 DOI: 10.1111/j.1476-5381.2011.01440.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND AND PURPOSE The endocannabinoid system appears to play a pivotal role in mediating the rewarding and reinforcing effects of nicotine. Recent studies have shown that the inhibition of fatty acid amide hydrolase (FAAH) attenuates reinstatement of nicotine-seeking induced by nicotine priming and nicotine-associated cues. FAAH hydrolyses the endogenous endocannabinoid anandamide, as well as other non-cannabinoid ligands such as oleoylethanolamide (OEA) and palmitoylethanolamide (PEA). As OEA and PEA can attenuate both nicotine-taking and nicotine-seeking behaviour, the specific role of anandamide remains unclear. In this study, we have tested the selective anadamide uptake inhibitor, VDM11, which elevates anandamide levels without affecting levels of OEA/PEA, on nicotine-taking and nicotine-seeking behaviour. EXPERIMENTAL APPROACH We used a nicotine intravenous self-administration model in rats to assess the effect of VDM11, given i.p., on nicotine taking using fixed and progressive ratio schedules of reinforcement as well as on reinstatement of nicotine-seeking induced by nicotine priming and nicotine-associated cues. KEY RESULTS VDM11 did not affect levels of responding for nicotine under fixed-ratio and progressive-ratio schedules of reinforcement. In contrast, VDM11 dose-dependently attenuated reinstatement of nicotine-seeking behaviour induced by nicotine-associated cues and nicotine priming. CONCLUSIONS AND IMPLICATIONS These results indicate that ligands elevating anandamide levels could have therapeutic value for preventing relapse into nicotine-seeking behaviour and should be tested in humans trying to quit smoking.
Collapse
Affiliation(s)
- Islam Gamaleddin
- Translational Addiction Research Laboratory, Centre for Addiction and Mental Health, Toronto, Canada
| | | | | | | |
Collapse
|
29
|
Kaczocha M, Vivieca S, Sun J, Glaser ST, Deutsch DG. Fatty acid-binding proteins transport N-acylethanolamines to nuclear receptors and are targets of endocannabinoid transport inhibitors. J Biol Chem 2011; 287:3415-24. [PMID: 22170058 DOI: 10.1074/jbc.m111.304907] [Citation(s) in RCA: 139] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
N-acylethanolamines (NAEs) are bioactive lipids that engage diverse receptor systems. Recently, we identified fatty acid-binding proteins (FABPs) as intracellular NAE carriers. Here, we provide two new functions for FABPs in NAE signaling. We demonstrate that FABPs mediate the nuclear translocation of the NAE oleoylethanolamide, an agonist of nuclear peroxisome proliferator-activated receptor α (PPARα). Antagonism of FABP function through chemical inhibition, dominant-negative approaches, or shRNA-mediated knockdown reduced PPARα activation, confirming a requisite role for FABPs in this process. In addition, we show that NAE analogs, traditionally employed as inhibitors of the putative endocannabinoid transmembrane transporter, target FABPs. Support for the existence of the putative membrane transporter stems primarily from pharmacological inhibition of endocannabinoid uptake by such transport inhibitors, which are widely employed in endocannabinoid research despite lacking a known cellular target(s). Our approach adapted FABP-mediated PPARα signaling and employed in vitro binding, arachidonoyl-[1-(14)C]ethanolamide ([(14)C]AEA) uptake, and FABP knockdown to demonstrate that transport inhibitors exert their effects through inhibition of FABPs, thereby providing a molecular rationale for the underlying physiological effects of these compounds. Identification of FABPs as targets of transport inhibitors undermines the central pharmacological support for the existence of an endocannabinoid transmembrane transporter.
Collapse
Affiliation(s)
- Martin Kaczocha
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York 11794-5215, USA.
| | | | | | | | | |
Collapse
|
30
|
A catalytically silent FAAH-1 variant drives anandamide transport in neurons. Nat Neurosci 2011; 15:64-9. [PMID: 22101642 PMCID: PMC3245783 DOI: 10.1038/nn.2986] [Citation(s) in RCA: 134] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2011] [Accepted: 10/17/2011] [Indexed: 11/08/2022]
Abstract
The endocannabinoid anandamide is removed from the synaptic space by a selective transport system, expressed in neurons and astrocytes, that remains molecularly uncharacterized. Here we describe a partly cytosolic variant of the intracellular anandamide-degrading enzyme fatty acid amide hydrolase-1 (FAAH-1), termed FAAH-like anandamide transporter (FLAT), that lacked amidase activity but bound anandamide with low micromolar affinity and facilitated its translocation into cells. Known anandamide transport inhibitors, such as AM404 and OMDM-1, blocked these effects. We also identified a competitive antagonist of the interaction of anandamide with FLAT, the phthalazine derivative ARN272, that prevented anandamide internalization in vitro, interrupted anandamide deactivation in vivo and exerted profound analgesic effects in rodent models of nociceptive and inflammatory pain, which were mediated by CB(1) cannabinoid receptors. The results identify FLAT as a critical molecular component of anandamide transport in neural cells and a potential target for therapeutic drugs.
Collapse
|
31
|
Involvement of endocannabinoids in antidepressant and anti-compulsive effect of fluoxetine in mice. Behav Brain Res 2011; 223:125-34. [DOI: 10.1016/j.bbr.2011.04.031] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 04/11/2011] [Accepted: 04/20/2011] [Indexed: 01/17/2023]
|
32
|
Ayoub SS, Pryce G, Seed MP, Bolton C, Flower RJ, Baker D. Paracetamol-induced hypothermia is independent of cannabinoids and transient receptor potential vanilloid-1 and is not mediated by AM404. Drug Metab Dispos 2011; 39:1689-95. [PMID: 21628499 DOI: 10.1124/dmd.111.038638] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In recent years, there has been increasing interest in hypothermia induced by paracetamol for therapeutic purposes, which, in some instances, has been reported as a side effect. Understanding the mechanism by which paracetamol induces hypothermia is therefore an important question. In this study, we investigated whether the novel metabolite of paracetamol, N-(4-hydroxyphenyl)arachidonylamide (AM404), which activates the cannabinoid (CB) and transient receptor potential vanilloid-1 (TRPV1) systems, mediates the paracetamol-induced hypothermia. The hypothermic response to 300 mg/kg paracetamol in CB(1) receptor (CB(1)R) and TRPV1 knockout mice was compared to wild-type mice. Hypothermia induced by paracetamol was also investigated in animals pretreated with the CB(1)R or TRPV1 antagonist 1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-1-piperdinyl-1H-pyrazole-3-carboxamide trifluoroacetate salt (AM251) or 4'-chloro-3-methoxycinnamanilide (SB366791), respectively. In CB(1)R or TRPV1 knockout mice, paracetamol induced hypothermia to the same extent as in wild-type mice. In addition, in C57BL/6 mice pretreated with AM251 or SB366791, paracetamol induced hypothermia to the same extent as in control mice. AM404 failed to induce hypothermia at pharmacological doses. Inhibition of fatty acid amide hydrolase (FAAH), which is involved in the metabolism of paracetamol to AM404, did not prevent the development of hypothermia with paracetamol. Paracetamol also induced hypothermia in FAAH knockout mice to the same extent as wild-type mice. We conclude that paracetamol induces hypothermia independent of cannabinoids and TRPV1 and that AM404 does not mediate this response. In addition, potential therapeutic value of combinational drug-induced hypothermia is supported by experimental evidence.
Collapse
Affiliation(s)
- Samir S Ayoub
- Centre for Biochemical Pharmacology, William Harvey Research Institute, Barts and London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK.
| | | | | | | | | | | |
Collapse
|
33
|
Karst M, Wippermann S, Ahrens J. Role of cannabinoids in the treatment of pain and (painful) spasticity. Drugs 2011; 70:2409-38. [PMID: 21142261 DOI: 10.2165/11585260-000000000-00000] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Both the discovery of the endocannabinoid system (ECS) and its role in the control of pain and habituation to stress, as well as the significant analgesic and antihyperalgesic effects in animal studies, suggest the usefulness of cannabinoids in pain conditions. However, in human experimental or clinical trials, no convincing reduction of acute pain, which may be caused by a pronociceptive, ECS-triggered mechanism on the level of the spinal cord, has been demonstrated. In contrast, in chronic pain and (painful) spasticity, an increasing number of randomized, double-blind, placebo-controlled studies have shown the efficacy of cannabinoids, which is combined with a narrow therapeutic index. Patients with unsatisfactory response to other methods of pain therapy and who were characterized by failed stress adaptation particularly benefited from treatment with cannabinoids. None of the attempts to overcome the disadvantage of the narrow therapeutic index, either by changing the route of application or by formulating balanced cannabinoid preparations, have resulted in a major breakthrough. Therefore, different methods of administration and other types of cannabinoids, such as endocannabinoid modulators, should be tested in future trials.
Collapse
Affiliation(s)
- Matthias Karst
- Department of Anaesthesiology, Pain Clinic, Hannover Medical School, Hannover, Germany.
| | | | | |
Collapse
|
34
|
Mallet C, Barrière DA, Ermund A, Jönsson BAG, Eschalier A, Zygmunt PM, Högestätt ED. TRPV1 in brain is involved in acetaminophen-induced antinociception. PLoS One 2010; 5. [PMID: 20862299 PMCID: PMC2941447 DOI: 10.1371/journal.pone.0012748] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Accepted: 08/23/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Acetaminophen, the major active metabolite of acetanilide in man, has become one of the most popular over-the-counter analgesic and antipyretic agents, consumed by millions of people daily. However, its mechanism of action is still a matter of debate. We have previously shown that acetaminophen is further metabolized to N-(4-hydroxyphenyl)-5Z,8Z,11Z,14Z -eicosatetraenamide (AM404) by fatty acid amide hydrolase (FAAH) in the rat and mouse brain and that this metabolite is a potent activator of transient receptor potential vanilloid 1 (TRPV(1)) in vitro. Pharmacological activation of TRPV(1) in the midbrain periaqueductal gray elicits antinociception in rats. It is therefore possible that activation of TRPV(1) in the brain contributes to the analgesic effect of acetaminophen. METHODOLOGY/PRINCIPAL FINDINGS Here we show that the antinociceptive effect of acetaminophen at an oral dose lacking hypolocomotor activity is absent in FAAH and TRPV(1) knockout mice in the formalin, tail immersion and von Frey tests. This dose of acetaminophen did not affect the global brain contents of prostaglandin E(2) (PGE(2)) and endocannabinoids. Intracerebroventricular injection of AM404 produced a TRPV(1)-mediated antinociceptive effect in the mouse formalin test. Pharmacological inhibition of TRPV(1) in the brain by intracerebroventricular capsazepine injection abolished the antinociceptive effect of oral acetaminophen in the same test. CONCLUSIONS This study shows that TRPV(1) in brain is involved in the antinociceptive action of acetaminophen and provides a strategy for developing central nervous system active oral analgesics based on the coexpression of FAAH and TRPV(1) in the brain.
Collapse
Affiliation(s)
- Christophe Mallet
- Clermont Université, Université d'Auvergne, Pharmacologie fondamentale et clinique de la douleur, Clermont-Ferrand, France
- Inserm, U 766, Clermont-Ferrand, France
| | - David A. Barrière
- Clermont Université, Université d'Auvergne, Pharmacologie fondamentale et clinique de la douleur, Clermont-Ferrand, France
- Inserm, U 766, Clermont-Ferrand, France
| | - Anna Ermund
- Department of Clinical Chemistry and Pharmacology, Lund University and Lund University Pain Research Centre, Lund, Sweden
| | - Bo A. G. Jönsson
- Department of Occupational and Environmental Medicine, Lund University, Lund, Sweden
| | - Alain Eschalier
- Clermont Université, Université d'Auvergne, Pharmacologie fondamentale et clinique de la douleur, Clermont-Ferrand, France
- Inserm, U 766, Clermont-Ferrand, France
| | - Peter M. Zygmunt
- Department of Clinical Chemistry and Pharmacology, Lund University and Lund University Pain Research Centre, Lund, Sweden
- * E-mail:
| | - Edward D. Högestätt
- Department of Clinical Chemistry and Pharmacology, Lund University and Lund University Pain Research Centre, Lund, Sweden
| |
Collapse
|
35
|
|
36
|
Ashton JC, Glass M. The cannabinoid CB2 receptor as a target for inflammation-dependent neurodegeneration. Curr Neuropharmacol 2010; 5:73-80. [PMID: 18615177 DOI: 10.2174/157015907780866884] [Citation(s) in RCA: 215] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2006] [Revised: 02/01/2007] [Accepted: 02/02/2007] [Indexed: 12/31/2022] Open
Abstract
Endocannabinoids are released following brain injury and may protect against excitotoxic damage during the acute stage of injury. Brain injury also activates microglia in a secondary inflammatory phase of more widespread damage. Most drugs targeting the acute stage are not effective if administered more than 6 hours after injury. Therefore, drugs targeting microglia later in the neurodegenerative cascade are desirable. We have found that cannabinoid CB2 receptors are up-regulated during the activation of microglia following brain injury. Specifically, CB2-positive cells appear in the rat brain following both hypoxia-ischemia (HI) and middle cerebral artery occlusion (MCAO). This may regulate post-injury microglial activation and inflammatory functions. In this paper we review in vivo and in vitro studies of CB2 receptors in microglia, including our results on CB2 expression post-injury. Taken together, studies show that CB2 is up-regulated during a process in which microglia become primed to proliferate, and then become fully reactive. In addition, CB2 activation appears to prevent or decrease microglial activation. In a rodent model of Alzheimer's disease microglial activation was completely prevented by administration of a selective CB2 agonist. The presence of CB2 receptors in microglia in the human Alzheimer's diseased brain suggests that CB2 may provide a novel target for a range of neuropathologies. We conclude that the administration of CB2 agonists and antagonists may differentially alter microglia-dependent neuroinflammation. CB2 specific compounds have considerable therapeutic appeal over CB1 compounds, as the exclusive expression of CB2 on immune cells within the brain provides a highly specialised target, without the psychoactivity that plagues CB1 directed therapies.
Collapse
Affiliation(s)
- John C Ashton
- Department of Pharmacology & Toxicology, University of Otago, PO Box 913, Dunedin, New Zealand.
| | | |
Collapse
|
37
|
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.
Collapse
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.
| | | | | | | | | |
Collapse
|
38
|
Alkaitis MS, Solorzano C, Landry RP, Piomelli D, DeLeo JA, Romero-Sandoval EA. Evidence for a role of endocannabinoids, astrocytes and p38 phosphorylation in the resolution of postoperative pain. PLoS One 2010; 5:e10891. [PMID: 20531936 PMCID: PMC2878341 DOI: 10.1371/journal.pone.0010891] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Accepted: 05/05/2010] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND An alarming portion of patients develop persistent or chronic pain following surgical procedures, but the mechanisms underlying the transition from acute to chronic pain states are not fully understood. In general, endocannabinoids (ECBs) inhibit nociceptive processing by stimulating cannabinoid receptors type 1 (CB(1)) and type 2 (CB(2)). We have previously shown that intrathecal administration of a CB(2) receptor agonist reverses both surgical incision-induced behavioral hypersensitivity and associated over-expression of spinal glial markers. We therefore hypothesized that endocannabinoid signaling promotes the resolution of acute postoperative pain by modulating pro-inflammatory signaling in spinal cord glial cells. METHODOLOGY/PRINCIPAL FINDINGS To test this hypothesis, rats receiving paw incision surgery were used as a model of acute postoperative pain that spontaneously resolves. We first characterized the concentration of ECBs and localization of CB(1) and CB(2) receptors in the spinal cord following paw incision. We then administered concomitant CB(1) and CB(2) receptor antagonists/inverse agonists (AM281 and AM630, 1 mg x kg(-1) each, i.p.) during the acute phase of paw incision-induced mechanical allodynia and evaluated the expression of glial cell markers and phosphorylated p38 (a MAPK associated with inflammation) in the lumbar dorsal horn. Dual blockade of CB(1) and CB(2) receptor signaling prevented the resolution of postoperative allodynia and resulted in persistent over-expression of spinal Glial Fibrillary Acidic Protein (GFAP, an astrocytic marker) and phospho-p38 in astrocytes. We provide evidence for the functional significance of these astrocytic changes by demonstrating that intrathecal administration of propentofylline (50 microg, i.t.) attenuated both persistent behavioral hypersensitivity and over-expression of GFAP and phospho-p38 in antagonist-treated animals. CONCLUSIONS/SIGNIFICANCE Our results demonstrate that endocannabinoid signaling via CB(1) and CB(2) receptors is necessary for the resolution of paw incision-induced behavioral hypersensitivity and for the limitation of pro-inflammatory signaling in astrocytes following surgical insult. Our findings suggest that therapeutic strategies designed to enhance endocannabinoid signaling may prevent patients from developing persistent or chronic pain states following surgery.
Collapse
MESH Headings
- Animals
- Astrocytes/drug effects
- Astrocytes/metabolism
- Astrocytes/pathology
- Behavior, Animal/drug effects
- Biomarkers/metabolism
- Calcium-Binding Proteins/metabolism
- Cannabinoid Receptor Modulators/metabolism
- Endocannabinoids
- Glial Fibrillary Acidic Protein/metabolism
- Male
- Microfilament Proteins
- Neuroglia/drug effects
- Neuroglia/metabolism
- Pain, Postoperative/enzymology
- Pain, Postoperative/pathology
- Phosphorylation/drug effects
- Rats
- Rats, Sprague-Dawley
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB2/antagonists & inhibitors
- Receptor, Cannabinoid, CB2/metabolism
- Spinal Cord/metabolism
- Spinal Cord/pathology
- Xanthines/pharmacology
- p38 Mitogen-Activated Protein Kinases/metabolism
Collapse
Affiliation(s)
- Matthew S. Alkaitis
- Neuroscience Center at Dartmouth, Dartmouth Medical School, Lebanon, New Hampshire, United States of America
- Nuffield Department of Clinical Laboratory Sciences, University of Oxford, Oxford, United Kingdom
| | - Carlos Solorzano
- Departments of Pharmacology and Biological Chemistry, University of California Irvine, Irvine, California, United States of America
| | - Russell P. Landry
- Neuroscience Center at Dartmouth, Dartmouth Medical School, Lebanon, New Hampshire, United States of America
- Department of Anesthesiology, Dartmouth Medical School, Lebanon, New Hampshire, United States of America
| | - Daniele Piomelli
- Departments of Pharmacology and Biological Chemistry, University of California Irvine, Irvine, California, United States of America
| | - Joyce A. DeLeo
- Neuroscience Center at Dartmouth, Dartmouth Medical School, Lebanon, New Hampshire, United States of America
- Department of Anesthesiology, Dartmouth Medical School, Lebanon, New Hampshire, United States of America
- Department of Pharmacology and Toxicology, Dartmouth Medical School, Lebanon, New Hampshire, United States of America
| | - E. Alfonso Romero-Sandoval
- Neuroscience Center at Dartmouth, Dartmouth Medical School, Lebanon, New Hampshire, United States of America
- Department of Anesthesiology, Dartmouth Medical School, Lebanon, New Hampshire, United States of America
- Department of Pharmacology and Toxicology, Dartmouth Medical School, Lebanon, New Hampshire, United States of America
| |
Collapse
|
39
|
Sagar DR, Jhaveri MD, Richardson D, Gray RA, de Lago E, Fernández-Ruiz J, Barrett DA, Kendall DA, Chapman V. Endocannabinoid regulation of spinal nociceptive processing in a model of neuropathic pain. Eur J Neurosci 2010; 31:1414-22. [PMID: 20384778 DOI: 10.1111/j.1460-9568.2010.07162.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Models of neuropathic pain are associated with elevated spinal levels of endocannabinoids (ECs) and altered expression of cannabinoid receptors on primary sensory afferents and post-synaptic cells in the spinal cord. We investigated the impact of these changes on the spinal processing of sensory inputs in a model of neuropathic pain. Extracellular single-unit recordings of spinal neurones were made in anaesthetized neuropathic and sham-operated rats. The effects of spinal administration of the cannabinoid CB(1) receptor antagonist N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (AM251) and the cannabinoid receptor type 2 (CB(2)) receptor antagonist N-[(1S)-endo-1,3,3-trimethylbicycloheptan-2-yl]-5-(4-chloro-3-methylphenyl)-1-(4-methylbenzyl)-pyrazole-3-carboxamide (SR144528) on mechanically-evoked responses of spinal neurones were determined. The effects of spinal administration of (5Z,8Z11Z,14Z)-N-(3-furanylmethyl)-5,8,11,14-eicosatetraenamide (UCM707), which binds to CB(2) receptors and alters transport of ECs, on evoked responses of spinal neurones and spinal levels of ECs were also determined. The cannabinoid CB(1) receptor antagonist AM251, but not the CB(2) receptor antagonist, significantly facilitated 10-g-evoked responses of spinal neurones in neuropathic, but not sham-operated, rats. Spinal administration of UCM707 did not alter spinal levels of ECs but did significantly inhibit mechanically-evoked responses of neurones in neuropathic, but not sham-operated, rats. Pharmacological studies indicated that the selective inhibitory effects of spinal UCM707 in neuropathic rats were mediated by activation of spinal CB(2) receptors, as well as a contribution from transient receptor potential vanilloid 1 (TRPV1) channels. This work demonstrates that changes in the EC receptor system in the spinal cord of neuropathic rats influence the processing of sensory inputs, in particular low-weight inputs that drive allodynia, and indicates novel effects of drugs acting via multiple elements of this receptor system.
Collapse
Affiliation(s)
- Devi Rani Sagar
- School of Biomedical Sciences, University of Nottingham, Medical School, Queen's Medical Centre, Nottingham, UK.
| | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Onnis V, Congiu C, Björklund E, Hempel F, Söderström E, Fowler CJ. Synthesis and evaluation of paracetamol esters as novel fatty acid amide hydrolase inhibitors. J Med Chem 2010; 53:2286-98. [PMID: 20143779 DOI: 10.1021/jm901891p] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Fatty acid amide hydrolase (FAAH) is the key hydrolytic enzyme for the endogenous cannabinoid receptor ligand anandamide. The synthesis and evaluation for their FAAH inhibitory activities of a series of 18 paracetamol esters are described. Structure-activity relationship studies indicated that the ester (33) with a 2-(4-(2-(trifluoromethyl)pyridin-4-ylamino)phenyl)acetic acid substituent was the most potent analogue in this series. The compound inhibited FAAH activity in a competitive manner with a K(i) value of 0.16 microM. The compound was also able to inhibit the FAAH activity in rat basophilic leukemia cells as assessed by measuring either the hydrolysis of anandamide, the FAAH-dependent cellular accumulation of anandamide, or the FAAH-dependent recycling of tritium to the cell membranes. The compound also inhibited the activity of monoacylglycerol lipase (MGL), the enzyme responsible for the hydrolysis of the endogenous cannabinoid receptor ligand 2-arachidonoylglycerol, with an IC(50) value of 1.9 microM. It is concluded that the compound may be a useful template for the design of potent novel inhibitors of FAAH.
Collapse
Affiliation(s)
- Valentina Onnis
- Department of Toxicology, Unit of Medicinal Chemistry, University of Cagliari, via Ospedale 72, Cagliari I-09124, Italy.
| | | | | | | | | | | |
Collapse
|
41
|
1-(2′,4′-dichlorophenyl)-6-methyl-N-cyclohexylamine-1,4-dihydroindeno[1,2-c]pyrazole-3-carboxamide, a novel CB2 agonist, alleviates neuropathic pain through functional microglial changes in mice. Neurobiol Dis 2010; 37:177-85. [DOI: 10.1016/j.nbd.2009.09.021] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Revised: 09/18/2009] [Accepted: 09/27/2009] [Indexed: 12/14/2022] Open
|
42
|
Hama AT, Sagen J. Cannabinoid receptor-mediated antinociception with acetaminophen drug combinations in rats with neuropathic spinal cord injury pain. Neuropharmacology 2009; 58:758-66. [PMID: 20035773 DOI: 10.1016/j.neuropharm.2009.12.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Revised: 12/10/2009] [Accepted: 12/13/2009] [Indexed: 12/16/2022]
Abstract
Pre-clinical evidence demonstrates that neuropathic spinal cord injury (SCI) pain is maintained by a number of neurobiological mechanisms, suggesting that treatments directed at several pain-related targets may be more advantageous compared to a treatment focused on a single target. The current study evaluated the efficacy of the non-opiate analgesic acetaminophen, which has several putative analgesic mechanisms, combined with analgesic drugs used to treat neuropathic pain in a rat model of below-level neuropathic SCI pain. Following an acute compression of the mid-thoracic spinal cord, rats exhibited robust hind paw hypersensitivity to innocuous mechanical stimulation. Fifty percent antinociceptive doses of gabapentin, morphine, tramadol or memantine were combined with an ineffective dose of acetaminophen; acetaminophen alone was not antinociceptive. The combination of acetaminophen with either tramadol or memantine resulted in an additive antinociceptive effect. Acetaminophen combined with either morphine or gabapentin, however, resulted in supra-additive (synergistic) efficacy. One of the analgesic mechanisms of acetaminophen is inhibiting the uptake of endocannabinoids from the extracellular space. Pre-treatment with AM251, a cannabinoid-1 receptor (CB1) antagonist, significantly diminished the antinociceptive effect of the acetaminophen + gabapentin combination. Pre-treatment with AM630, a cannabinoid-2 receptor (CB2) antagonist, did not have an effect on this combination. By contrast, both AM251 and AM630 reduced the efficacy of the acetaminophen + morphine combination. None of the active drugs alone were affected by either CB receptor antagonist. The results imply that modulation of the endocannabinoid system in addition to other mechanisms mediate the synergistic antinociceptive effects of acetaminophen combinations. Despite the presence of a cannabinoid mechanism, synergism was not present in all acetaminophen combinations. The combination of currently available drugs may be an appropriate option in ameliorating neuropathic SCI pain if single drug therapy is ineffective.
Collapse
Affiliation(s)
- Aldric T Hama
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, 1095 NW 14th Terrace (R-48), Miami, FL 33136, USA.
| | | |
Collapse
|
43
|
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.
Collapse
Affiliation(s)
- Josée Guindon
- Neuroscience and Behavior Program, Department of Psychology, University of Georgia, Athens, GA 30602-3013, USA
| | | |
Collapse
|
44
|
Chu KM, Ngan MP, Wai MK, Yeung CK, Andrews PLR, Percie du Sert N, Rudd JA. Olvanil: a non-pungent TRPV1 activator has anti-emetic properties in the ferret. Neuropharmacology 2009; 58:383-91. [PMID: 19825380 DOI: 10.1016/j.neuropharm.2009.10.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Revised: 10/02/2009] [Accepted: 10/02/2009] [Indexed: 01/31/2023]
Abstract
Anti-emetic drugs such as the tachykinin NK(1) receptor antagonists are useful to control emesis induced by diverse challenges. Evidence suggests pungent capsaicin-like TRPV1 activators also have broad inhibitory anti-emetic activity. However, pungent compounds are associated with undesirable effects including adverse actions on the cardiovascular system and on temperature homeostasis. In the present investigations using the ferret, we examine if the non-pungent vanilloid, olvanil, has useful anti-emetic properties without adversely affecting behaviour, blood pressure or temperature control. Olvanil (0.05-5 mg/kg, s.c.) was compared to the pungent vanilloid, resiniferatoxin (RTX; 0.1 mg/kg, s.c.), and to the anandamide reuptake inhibitor, AM404 (10 mg/kg, s.c.), for a potential to inhibit emesis induced by apomorphine (0.25 mg/kg, s.c.), copper sulphate (50 mg/kg, intragastric), and cisplatin (10 mg/kg, i.p.). Changes in blood pressure and temperature were also recorded using radiotelemetry implants. In peripheral administration studies, RTX caused transient hypertension, hypothermia and reduced food and water intake, but also significantly inhibited emesis induced by apomorphine, copper sulphate, or cisplatin. Olvanil did not have a similar adverse profile, and antagonised apomorphine- and cisplatin-induced emesis but not that induced by copper sulphate. AM404 reduced only emesis induced by cisplatin without affecting other parameters measured. Following intracerebral administration only olvanil antagonised cisplatin-induced emesis, but this was associated with transient hypothermia. In conclusion, olvanil demonstrated clear anti-emetic activity in the absence of overt cardiovascular, homeostatic, or behavioural effects associated with the pungent vanilloid, RTX. Our studies indicate that non-pungent vanilloids may have a useful spectrum of anti-emetic properties via central and/or peripheral mechanisms after peripheral administration.
Collapse
Affiliation(s)
- Kit-Man Chu
- Emesis Research Group, Brain-Gut Laboratory, Department of Pharmacology, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | | | | | | | | | | | | |
Collapse
|
45
|
Rahn EJ, Hohmann AG. Cannabinoids as pharmacotherapies for neuropathic pain: from the bench to the bedside. Neurotherapeutics 2009; 6:713-37. [PMID: 19789075 PMCID: PMC2755639 DOI: 10.1016/j.nurt.2009.08.002] [Citation(s) in RCA: 208] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Neuropathic pain is a debilitating form of chronic pain resulting from nerve injury, disease states, or toxic insults. Neuropathic pain is often refractory to conventional pharmacotherapies, necessitating validation of novel analgesics. Cannabinoids, drugs that share the same target as Delta(9)-tetrahydrocannabinol (Delta(9)-THC), the psychoactive ingredient in cannabis, have the potential to address this unmet need. Here, we review studies evaluating cannabinoids for neuropathic pain management in the clinical and preclinical literature. Neuropathic pain associated with nerve injury, diabetes, chemotherapeutic treatment, human immunodeficiency virus, multiple sclerosis, and herpes zoster infection is considered. In animals, cannabinoids attenuate neuropathic nociception produced by traumatic nerve injury, disease, and toxic insults. Effects of mixed cannabinoid CB(1)/CB(2) agonists, CB(2) selective agonists, and modulators of the endocannabinoid system (i.e., inhibitors of transport or degradation) are compared. Effects of genetic disruption of cannabinoid receptors or enzymes controlling endocannabinoid degradation on neuropathic nociception are described. Specific forms of allodynia and hyperalgesia modulated by cannabinoids are also considered. In humans, effects of smoked marijuana, synthetic Delta(9)-THC analogs (e.g., Marinol, Cesamet) and medicinal cannabis preparations containing both Delta(9)-THC and cannabidiol (e.g., Sativex, Cannador) in neuropathic pain states are reviewed. Clinical studies largely affirm that neuropathic pain patients derive benefits from cannabinoid treatment. Subjective (i.e., rating scales) and objective (i.e., stimulus-evoked) measures of pain and quality of life are considered. Finally, limitations of cannabinoid pharmacotherapies are discussed together with directions for future research.
Collapse
Affiliation(s)
- Elizabeth J. Rahn
- grid.213876.9000000041936738XNeuroscience and Behavior Program, Department of Psychology, University of Georgia, 30602-3013 Athens, GA
| | - Andrea G. Hohmann
- grid.213876.9000000041936738XNeuroscience and Behavior Program, Department of Psychology, University of Georgia, 30602-3013 Athens, GA
| |
Collapse
|
46
|
Hasanein P. The endocannabinoid transport inhibitor AM404 modulates nociception in cholestasis. Neurosci Lett 2009; 462:230-4. [DOI: 10.1016/j.neulet.2009.07.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2009] [Revised: 07/08/2009] [Accepted: 07/10/2009] [Indexed: 10/20/2022]
|
47
|
Pacheco DDF, Klein A, Perez AC, Pacheco CMDF, de Francischi JN, Reis GML, Duarte IDG. Central antinociception induced by mu-opioid receptor agonist morphine, but not delta- or kappa-, is mediated by cannabinoid CB1 receptor. Br J Pharmacol 2009; 158:225-31. [PMID: 19594755 DOI: 10.1111/j.1476-5381.2009.00310.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND AND PURPOSE It has been demonstrated that cannabinoids evoke the release of endogenous opioids to produce antinociception; however, no information exists regarding the participation of cannabinoids in the antinociceptive mechanisms of opioids. The aim of the present study was to determine whether endocannabinoids are involved in central antinociception induced by activation of mu-, delta- and kappa-opioid receptors. EXPERIMENTAL APPROACH Nociceptive threshold to thermal stimulation was measured according to the tail-flick test in Swiss mice. Morphine (5 microg), SNC80 (4 microg), bremazocine (4 microg), AM251 (2 and 4 microg), AM630 (2 and 4 microg) and MAFP (0.1 and 0.4 microg) were administered by the intracerebroventricular route. KEY RESULTS The CB(1)-selective cannabinoid receptor antagonist AM251 completely reversed the central antinociception induced by morphine in a dose-dependent manner. In contrast, the CB(2)-selective cannabinoid receptor antagonist AM630 did not antagonize this effect. Additionally, the administration of the anandamide amidase inhibitor, MAFP, significantly enhanced the antinociception induced by morphine. In contrast, the antinociceptive effects of delta- and kappa-opioid receptor agonists were not affected by the cannabinoid antagonists. The antagonists alone caused no hyperalgesic or antinociceptive effects. CONCLUSIONS AND IMPLICATIONS The results provide evidence for the involvement of cannabinoid CB(1) receptors in the central antinociception induced by activation of mu-opioid receptors by the agonist morphine. The release of endocannabinoids appears not to be involved in central antinociception induced by activation of kappa- and delta-opioid receptors.
Collapse
Affiliation(s)
- Daniela da Fonseca Pacheco
- Department of Pharmacology, Institute of Biological Sciences, UFMG, Av. Antônio Carlos, Belo Horizonte, Brazil
| | | | | | | | | | | | | |
Collapse
|
48
|
Hasanein P, Javanmardi K. A potent and selective inhibitor of endocannabinoid uptake, UCM707, potentiates antinociception induced by cholestasis. Fundam Clin Pharmacol 2009; 22:517-22. [PMID: 18844724 DOI: 10.1111/j.1472-8206.2008.00626.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cholestasis is associated with changes including analgesia. The endocannabinoid system can reduce pain sensitivity. Considering the interaction between the endogenous opioid and endocannabinoid systems in nociception processing, we studied the effect of UCM707 as a potent and selective inhibitor of endocannabinoid uptake on modulation of nociception in a model of elevated endogenous opioid tone, cholestasis. Cholestasis was induced in male Sprague-Dawley rats by ligation of the main bile duct using two ligatures and transecting the duct at the midpoint between them. Seven days later, tail-flick latencies were measured 10 min after injection of UCM707 (0.1, 1 and 10 mg/kg, i.p.) alone or with co-administration of a CB(1) receptor antagonist, AM251 (1 mg/kg, i.p.), with UCM707 (10 mg/kg, i.p.) in experimental groups. A significant increase (P < 0.01) in tail-flick latency was observed in cholestatic rats compared with rats belonging to unoperated and sham groups. Administration of UCM707 (1 and 10 mg/kg) to cholestatic animals significantly increased tail-flick latency compared with the vehicle-treated cholestatic group (P < 0.05 and P < 0.001, respectively). UCM707 injection in unoperated and sham groups did not alter baseline tail-flick latency compared with vehicle-treated groups. The effect of UCM707 in the cholestatic group was blocked by co-administration of AM251 (1 mg/kg, i.p.) with UCM707. These data showed that the endocannabinoid system is involved in nociception processing during cholestasis and that the effects of UCM707 on the pain threshold in cholestatic rats may be a result of CB(1) receptor activation by the increased extracellular levels of endocannabinoids.
Collapse
Affiliation(s)
- Parisa Hasanein
- Department of Biology, School of Basic Sciences, Bu-Ali Sina University, Hamadan, Iran.
| | | |
Collapse
|
49
|
Hasanein P, Soltani N. Effects of the endocannabinoid transport inhibitors AM404 and UCM707 on diabetic neuropathy in rats. Clin Exp Pharmacol Physiol 2009; 36:1127-31. [PMID: 19413593 DOI: 10.1111/j.1440-1681.2009.05197.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
1. Diabetic rats display increased pain responses following injection of formalin into the paw, suggesting the presence of hyperalgesia. In the present study, we investigated the efficacy of the systemic administration of the endocannabinoid transport inhibitors UCM707 and AM404 (1, 10 and 50 mg/kg, i.p.) on hyperalgesia during the formalin test in streptozocin (STZ)-induced diabetic rats. 2. Nociceptive testing was performed in male adult Wistar rats 4 weeks after the onset of hyperglycaemia. At the end of the experiment, all rats were weighed and then underwent plasma glucose measurements. 3. Diabetes caused significant hyperalgesia during both phases of the formalin test. At 10 and 50 mg/kg, both UCM707 and AM404 reversed chemical hyperalgesia in diabetic rats. UCM707 (10 and 50 mg/kg) caused less intensive nociceptive behaviour during both phases of the test, whereas AM404 (10 and 50 mg/kg) only affected pain scores during Phase 1 of the formalin test. At 1 mg, neither drug had any effect on pain behaviour in control and diabetic groups compared with their respective controls. Neither UCM707 nor AM404 had any effect on bodyweight or plasma glucose levels of treated compared with non-treated rats at any of the doses tested. 4. The results of the present study indicate that systemic administration of UCM707 and AM404 is effective in ameliorating chemical hyperalgesia in STZ-diabetic rats. Thus, endocannabinoid transport inhibitors may have potential in the treatment of painful diabetic neuropathy.
Collapse
Affiliation(s)
- Parisa Hasanein
- Department of Biology, School of Basic Sciences, Bu-Ali Sina University, Hamadan, Iran.
| | | |
Collapse
|
50
|
Mode of action of cannabinoids on nociceptive nerve endings. Exp Brain Res 2009; 196:79-88. [PMID: 19306092 DOI: 10.1007/s00221-009-1762-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2009] [Accepted: 02/27/2009] [Indexed: 12/22/2022]
Abstract
In recent years, cannabinoids have emerged as attractive alternatives or supplements to therapy for chronic pain states. However, in humans the activation of cannabinoid receptors in neurons of the central nervous system is associated with psychotropic side effects, temporary memory impairment and dependence, which arise via the effects of cannabinoids on forebrain circuits. For clinical exploitation of the analgesic properties of cannabinoids, a major challenge is to devise strategies that reduce or abolish their adverse effects on cognitive, affective and motor functions without attenuating their analgesic effects. The cannabinoid receptor family currently includes two cloned metabotropic receptors: CB1, CB2 and possibly GPR55 which are distributed widely across many key loci in pain-modulating pathways, including the peripheral terminals of primary afferents. Modulation of transducer ion channels expressed at nociceptive terminals occurs upon activation of metabotropic cannabinoid receptors, but direct cannabinoid action on ion channels involved in sensory transduction or regulation of neuron excitability likely contributes to the peripheral cannabinoid effects.
Collapse
|