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Sawynok J. Topical analgesics for neuropathic pain: Preclinical exploration, clinical validation, future development. Eur J Pain 2013; 18:465-81. [DOI: 10.1002/j.1532-2149.2013.00400.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/13/2013] [Indexed: 12/28/2022]
Affiliation(s)
- J. Sawynok
- Department of Pharmacology; Dalhousie University; Halifax Nova Scotia Canada
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52
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Lee KS, Asgar J, Zhang Y, Chung MK, Ro JY. The role of androgen receptor in transcriptional modulation of cannabinoid receptor type 1 gene in rat trigeminal ganglia. Neuroscience 2013; 254:395-403. [PMID: 24055403 DOI: 10.1016/j.neuroscience.2013.09.014] [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: 05/29/2013] [Revised: 09/04/2013] [Accepted: 09/05/2013] [Indexed: 12/31/2022]
Abstract
We have previously shown that anti-hyperalgesic effects of cannabinoid agonists under inflammatory condition are much greater in male than female, and that inflammatory cytokines upregulate cannabinoid receptor type 1 (CB1) expression in male, but not female, trigeminal ganglia (TG) in a testosterone-dependent manner. In this study, we investigated the mechanisms underlying the testosterone-mediated regulation of peripheral CB1 expression. We hypothesized that testosterone upregulates CB1 through transcriptional modulation by androgen receptor (AR). Interleukin-1 beta (IL-1β), a pro-inflammatory cytokine, upregulated CB1 mRNA expression in TG of male rats. The cytokine-induced upregulation was prevented by the pretreatment with flutamide, a specific antagonist for AR, but not by ICI 182,780, a specific antagonist for estrogen receptor, suggesting that the effects of testosterone are not mediated by estradiol, a testosterone metabolite. The expression levels of AR and IL-1β receptors were comparable between male and female TG, suggesting that the male specific IL-1β effects on CB1 upregulation occurs downstream to these receptors. The chromatin immunoprecipitation assay showed AR binding to the CB1 promoter in the rat TG. Furthermore, luciferase reporter assay revealed that AR activated the CB1 gene in response to testosterone or dihydrotestosterone treatment. These experiments provided compelling evidence that testosterone regulates CB1 gene transcription in TG through AR following cytokine stimulation. These results should provide mechanistic bases for understanding cytokine-hormone-neuron interactions in peripheral cannabinoid systems, and have important clinical implications for pain patients in whom testosterone level is naturally low, gradually declining or pharmacologically compromised.
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Affiliation(s)
- K S Lee
- University of Maryland Dental School, Department of Neural and Pain Sciences, Program in Neuroscience, Baltimore, MD 21201, USA
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53
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Sex differences in anti-allodynic, anti-hyperalgesic and anti-edema effects of Δ9-tetrahydrocannabinol in the rat. Pain 2013; 154:1709-1717. [DOI: 10.1016/j.pain.2013.05.017] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Revised: 03/20/2013] [Accepted: 05/09/2013] [Indexed: 12/11/2022]
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54
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Kalliomäki J, Annas P, Huizar K, Clarke C, Zettergren A, Karlsten R, Segerdahl M. Evaluation of the analgesic efficacy and psychoactive effects of AZD1940, a novel peripherally acting cannabinoid agonist, in human capsaicin-induced pain and hyperalgesia. Clin Exp Pharmacol Physiol 2013; 40:212-8. [PMID: 23324098 DOI: 10.1111/1440-1681.12051] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2012] [Revised: 12/09/2012] [Accepted: 01/01/2013] [Indexed: 11/30/2022]
Abstract
The aim of the present study was to investigate the effects of AZD1940, a novel peripherally acting cannabinoid CB(1) /CB(2) receptor agonist, on capsaicin-induced pain and hyperalgesia, as well as on biomarkers of cannabinoid central nervous system (CNS) effects. The present study was a randomized, double-blind, placebo-controlled, four-sequence, two-period, cross-over study in 44 male healthy volunteers aged 20-45 years. The effects of two single oral doses of AZD1940 (400 and 800 μg) were compared with placebo. Pain intensity after intradermal capsaicin injections in the forearm was assessed on a continuous visual analogue scale (VAS; 0-100 mm). Primary and secondary hyperalgesia induced by application of capsaicin cream on the calf were assessed by measuring heat pain thresholds and the area of mechanical allodynia, respectively. The CNS effects were assessed at baseline and up to 24 h after dosing using a visual analogue mood scales (VAMS) for feeling 'stimulated', 'high', 'anxious', 'sedated' or 'down'. AZD1940 did not significantly attenuate ongoing pain or primary or secondary hyperalgesia compared with placebo. Mild CNS effects for AZD1940were observed on the VAMS for 'high' and 'sedated'. Dose-dependent mild-to-moderate CNS-related and gastrointestinal adverse events were reported following treatment with AZD1940. No evidence of analgesic efficacy was found for a peripherally acting CB(1)/CB(2) receptor agonist in the human capsaicin pain model. The emergence of mild dose-dependent CNS effects suggests that the dose range predicted from preclinical data had been attained.
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55
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Affiliation(s)
- Paul Howard
- Duchess of Kent House, Reading, United Kingdom
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56
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Rom S, Persidsky Y. Cannabinoid receptor 2: potential role in immunomodulation and neuroinflammation. J Neuroimmune Pharmacol 2013; 8:608-20. [PMID: 23471521 PMCID: PMC3663904 DOI: 10.1007/s11481-013-9445-9] [Citation(s) in RCA: 166] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 02/18/2013] [Indexed: 01/02/2023]
Abstract
An accumulating body of evidence suggests that endocannabinoids and cannabinoid receptors type 1 and 2 (CB(1), CB(2)) play a significant role in physiologic and pathologic processes, including cognitive and immune functions. While the addictive properties of marijuana, an extract from the Cannabis plant, are well recognized, there is growing appreciation of the therapeutic potential of cannabinoids in multiple pathologic conditions involving chronic inflammation (inflammatory bowel disease, arthritis, autoimmune disorders, multiple sclerosis, HIV-1 infection, stroke, Alzheimer's disease to name a few), mainly mediated by CB(2) activation. Development of CB(2) agonists as therapeutic agents has been hampered by the complexity of their intracellular signaling, relative paucity of highly selective compounds and insufficient data regarding end effects in the target cells and organs. This review attempts to summarize recent advances in studies of CB(2) activation in the setting of neuroinflammation, immunomodulation and HIV-1 infection.
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Affiliation(s)
- Slava Rom
- Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia PA (USA)
| | - Yuri Persidsky
- Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia PA (USA)
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57
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Pertwee RG. Targeting the endocannabinoid system with cannabinoid receptor agonists: pharmacological strategies and therapeutic possibilities. Philos Trans R Soc Lond B Biol Sci 2013; 367:3353-63. [PMID: 23108552 DOI: 10.1098/rstb.2011.0381] [Citation(s) in RCA: 259] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Human tissues express cannabinoid CB(1) and CB(2) receptors that can be activated by endogenously released 'endocannabinoids' or exogenously administered compounds in a manner that reduces the symptoms or opposes the underlying causes of several disorders in need of effective therapy. Three medicines that activate cannabinoid CB(1)/CB(2) receptors are now in the clinic: Cesamet (nabilone), Marinol (dronabinol; Δ(9)-tetrahydrocannabinol (Δ(9)-THC)) and Sativex (Δ(9)-THC with cannabidiol). These can be prescribed for the amelioration of chemotherapy-induced nausea and vomiting (Cesamet and Marinol), stimulation of appetite (Marinol) and symptomatic relief of cancer pain and/or management of neuropathic pain and spasticity in adults with multiple sclerosis (Sativex). This review mentions several possible additional therapeutic targets for cannabinoid receptor agonists. These include other kinds of pain, epilepsy, anxiety, depression, Parkinson's and Huntington's diseases, amyotrophic lateral sclerosis, stroke, cancer, drug dependence, glaucoma, autoimmune uveitis, osteoporosis, sepsis, and hepatic, renal, intestinal and cardiovascular disorders. It also describes potential strategies for improving the efficacy and/or benefit-to-risk ratio of these agonists in the clinic. These are strategies that involve (i) targeting cannabinoid receptors located outside the blood-brain barrier, (ii) targeting cannabinoid receptors expressed by a particular tissue, (iii) targeting upregulated cannabinoid receptors, (iv) selectively targeting cannabinoid CB(2) receptors, and/or (v) adjunctive 'multi-targeting'.
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Affiliation(s)
- Roger G Pertwee
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK.
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58
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Involvement of the opioid and cannabinoid systems in pain control: new insights from knockout studies. Eur J Pharmacol 2013; 716:142-57. [PMID: 23523475 DOI: 10.1016/j.ejphar.2013.01.077] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 01/24/2013] [Accepted: 01/29/2013] [Indexed: 12/20/2022]
Abstract
The endogenous opioid and cannabinoid systems are involved in the physiological inhibitory control of pain and are of particular interest for the development of therapeutic approaches for pain management. The involvement of these endogenous systems in pain control has been studied from decades by the use of compounds with different affinities for each cannabinoid and opioid receptor or for the different enzymes involved in endocannabinoid and endogenous opioid metabolism. However, the selectivity of these pharmacological tools in vivo has represented an important limitation for these studies. The generation of genetically modified mice with selective mutations in specific components of the endocannabinoid and endogenous opioid system has provided important advances in the identification of the specific contribution of each component of these endogenous systems in the perception of noxious stimuli and the development of pathological pain states. Different lines of constitutive and conditional knockout mice deficient in specific cannabinoid and opioid receptors, specific precursors of the endogenous opioid peptides and the main enzymes involved in endocannabinoid and endogenous opioid degradation are now available. These knockout mice have also been used to evaluate the contribution of each component of the endocannabinoid and opioid system in the antinociceptive effects of cannabinoid and opioid agonists, including those currently used to treat pain in humans. This review summarizes the main advances provided in the last 15 years by the use of these genetic tools in the knowledge of the physiological control of pain and the pharmacology of cannabinoid and opioid compounds for pain management.
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Kalliomäki J, Segerdahl M, Webster L, Reimfelt A, Huizar K, Annas P, Karlsten R, Quiding H. Evaluation of the analgesic efficacy of AZD1940, a novel cannabinoid agonist, on post-operative pain after lower third molar surgical removal. Scand J Pain 2013; 4:17-22. [DOI: 10.1016/j.sjpain.2012.08.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Accepted: 08/24/2012] [Indexed: 10/27/2022]
Abstract
Abstract
Aim
To evaluate the analgesic efficacy of AZD1940, a novel peripherally acting cannabinoid CB1/CB2 receptor agonist, in patients undergoing third molar surgical removal.
Methods
This was a randomized, double-blind, placebo-controlled study in patients scheduled for surgical removal of an impacted lower third molar. Patients received a single oral dose of 800 μg AZD1940, 500 mg naproxen or placebo 1.5 h before surgery. The dose of 800 μg AZD1940 was selected based on earlier data from a single dose study in man, in which it was identified as the highest well tolerated dose. Ongoing post-operative pain (primary variable) and pain on jaw movement were assessed on a visual analog scale (VAS, 0-100 mm) from 0 to 8h postoperatively, deriving the area under the curve of ongoing pain (VAS AUC0–8h), and of pain on jaw movement (VASJM AUC0–8h). The time to requesting rescue medication (acetaminophen) was recorded. Subjective cannabinoid effects were assessed by the visual analog mood scale (VAMS).
Results
In total, 151 patients were randomized to AZD1940 (n = 61), placebo (n = 59) or naproxen (n = 31). There was no statistically significant difference in pain VAS AUC0–8h or in VASJM AUC0–8h between AZD1940 and placebo. Naproxen significantly reduced both pain VAS AUC0–8h and VASJM AUC0–8h as compared with placebo (p < 0.0001 for both). Significantly fewer patients on naproxen requested rescue medication and the duration of time to rescue was greater, as compared with placebo, whereas there were no significant differences between AZD1940 and placebo in these outcome variables. Statistically significant increases in VAMS items “sedated” and “high” were observed after AZD1940 compared with placebo. The increases in VAMS were numerically small compared with previous findings with a centrally acting cannabinoid. The most commonly observed adverse events (AE) on treatment with AZD1940 were postural dizziness (80% of subjects), nausea (26%), hypotension (21%) and headache (13%), most AE being mild to moderate.
Conclusion
The CB1/CB2 receptor agonist AZD1940 did not reduce post-operative pain after lower third molar surgical removal at doses exerting subjective cannabinoid effects.
Implications
Activation of peripheral CB1/CB2 receptors per se is probably of less clinical relevance for the treatment of acute nociceptive pain in man.
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Affiliation(s)
| | | | - Lynn Webster
- Lifetree Clinical Research , 3838 South, 700 East, Suite 202 , Salt Lake City , UT 84106 , USA
| | | | - Karin Huizar
- AstraZeneca R&D Södertälje , Södertälje , Sweden
| | - Peter Annas
- AstraZeneca R&D Södertälje , Södertälje , Sweden
| | | | - Hans Quiding
- AstraZeneca R&D Södertälje , Södertälje , Sweden
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60
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Plowright AT, Nilsson K, Antonsson M, Amin K, Broddefalk J, Jensen J, Lehmann A, Jin S, St-Onge S, Tomaszewski MJ, Tremblay M, Walpole C, Wei Z, Yang H, Ulander J. Discovery of Agonists of Cannabinoid Receptor 1 with Restricted Central Nervous System Penetration Aimed for Treatment of Gastroesophageal Reflux Disease. J Med Chem 2012; 56:220-40. [DOI: 10.1021/jm301511h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Alleyn T. Plowright
- AstraZeneca Research and Development, Pepparedsleden 1, Mölndal, 43183,
Sweden
| | - Karolina Nilsson
- AstraZeneca Research and Development, Pepparedsleden 1, Mölndal, 43183,
Sweden
| | - Madeleine Antonsson
- AstraZeneca Research and Development, Pepparedsleden 1, Mölndal, 43183,
Sweden
| | - Kosrat Amin
- AstraZeneca Research and Development, Pepparedsleden 1, Mölndal, 43183,
Sweden
| | - Johan Broddefalk
- AstraZeneca Research and Development, Pepparedsleden 1, Mölndal, 43183,
Sweden
| | - Jörgen Jensen
- AstraZeneca Research and Development, Pepparedsleden 1, Mölndal, 43183,
Sweden
| | - Anders Lehmann
- AstraZeneca Research and Development, Pepparedsleden 1, Mölndal, 43183,
Sweden
| | - Shujuan Jin
- AstraZeneca Research and Development, 7171 Frederick-Banting, Saint-Laurent,
Quebec, H4S 1Z9, Canada
| | - Stephane St-Onge
- AstraZeneca Research and Development, 7171 Frederick-Banting, Saint-Laurent,
Quebec, H4S 1Z9, Canada
| | - Mirosław J. Tomaszewski
- AstraZeneca Research and Development, 7171 Frederick-Banting, Saint-Laurent,
Quebec, H4S 1Z9, Canada
| | - Maxime Tremblay
- AstraZeneca Research and Development, 7171 Frederick-Banting, Saint-Laurent,
Quebec, H4S 1Z9, Canada
| | - Christopher Walpole
- AstraZeneca Research and Development, 7171 Frederick-Banting, Saint-Laurent,
Quebec, H4S 1Z9, Canada
| | - Zhongyong Wei
- AstraZeneca Research and Development, 7171 Frederick-Banting, Saint-Laurent,
Quebec, H4S 1Z9, Canada
| | - Hua Yang
- AstraZeneca Research and Development, 7171 Frederick-Banting, Saint-Laurent,
Quebec, H4S 1Z9, Canada
| | - Johan Ulander
- AstraZeneca Research and Development, Pepparedsleden 1, Mölndal, 43183,
Sweden
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61
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Kalliomäki J, Philipp A, Baxendale J, Annas P, Karlsten R, Segerdahl M. Lack of effect of central nervous system-active doses of nabilone on capsaicin-induced pain and hyperalgesia. Clin Exp Pharmacol Physiol 2012; 39:336-42. [PMID: 22233155 DOI: 10.1111/j.1440-1681.2012.05674.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The aim of the present study was to investigate the effects of nabilone on capsaicin-induced pain and hyperalgesia, as well as on biomarkers of cannabinoid central nervous system (CNS) effects. A randomized, double-blind, placebo-controlled, crossover study was conducted in 30 healthy male volunteers receiving single doses of nabilone (1, 2 or 3 mg). Pain intensity after intradermal capsaicin injections in the forearm was assessed by continuous visual analogue scale (0-100 mm). Capsaicin cream was applied to the calf to induce hyperalgesia. Primary hyperalgesia was assessed by measuring heat pain thresholds, whereas secondary hyperalgesia was assessed by measuring the area where light tactile stimulation was felt to be painful. Pain and hyperalgesia were measured at baseline and 2-3.5 h after dosing. The CNS effects were assessed at baseline and up to 24 h after dosing using visual analogue mood scales for feeling 'stimulated', 'anxious', 'sedated' and 'down'. Plasma samples for pharmacokinetic analysis were obtained up to 24 h after drug administration. Nabilone did not significantly attenuate either ongoing pain or primary or secondary hyperalgesia, whereas dose-dependent CNS effects were observed from 1.5 to 6 h after dosing, being maximal at 4-6 h. Plasma concentrations of nabilone and its metabolite carbinol were maximal 1-2 h after dosing. Adverse events (AE) were common on nabilone treatment. Four subjects withdrew due to pronounced CNS AE (anxiety, agitation, altered perception, impaired consciousness). Although nabilone had marked CNS effects, no analgesic or antihyperalgesic effects were observed.
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62
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Liu YQ, Qiu F, Qiu CY, Cai Q, Zou P, Wu H, Hu WP. Cannabinoids inhibit acid-sensing ion channel currents in rat dorsal root ganglion neurons. PLoS One 2012; 7:e45531. [PMID: 23029075 PMCID: PMC3446897 DOI: 10.1371/journal.pone.0045531] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 08/21/2012] [Indexed: 12/26/2022] Open
Abstract
Local acidosis has been found in various pain-generating conditions such as inflammation and tissue injury. Cannabinoids exert a powerful inhibitory control over pain initiation via peripheral cognate receptors. However, the peripheral molecular targets responsible for the antinociceptive effects of cannabinoids are still poorly understood. Here, we have found that WIN55,212-2, a cannabinoid receptor agonist, inhibits the activity of native acid-sensing ion channels (ASICs) in rat dorsal root ganglion (DRG) neurons. WIN55,212-2 dose-dependently inhibited proton-gated currents mediated by ASICs. WIN55,212-2 shifted the proton concentration–response curve downwards, with an decrease of 48.6±3.7% in the maximum current response but with no significant change in the EC50 value. The inhibition of proton-gated current induced by WIN55,212-2 was almost completely blocked by the selective CB1 receptor antagonist AM 281, but not by the CB2 receptor antagonist AM630. Pretreatment of forskolin, an AC activator, and the addition of cAMP also reversed the inhibition of WIN55,212-2. Moreover, WIN55,212-2 altered acid-evoked excitability of rat DRG neurons and decreased the number of action potentials induced by acid stimuli. Finally, WIN55,212-2 attenuated nociceptive responses to injection of acetic acid in rats. These results suggest that WIN55,212-2 inhibits the activity of ASICs via CB1 receptor and cAMP dependent pathway in rat primary sensory neurons. Thus, cannabinoids can exert their analgesic action by interaction with ASICs in the primary afferent neurons, which was novel analgesic mechanism of cannabinoids.
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Affiliation(s)
- Yu-Qiang Liu
- Department of Pharmacology, Hubei University of Science and Technology, Xianning, Hubei, P R China
| | - Fang Qiu
- Department of Pharmacology, Hubei University of Science and Technology, Xianning, Hubei, P R China
| | - Chun-Yu Qiu
- Department of Pharmacology, Hubei University of Science and Technology, Xianning, Hubei, P R China
| | - Qi Cai
- Department of Pharmacology, Hubei University of Science and Technology, Xianning, Hubei, P R China
| | - Pengcheng Zou
- Hubei Furen Pharmaceutical Corporation Ltd, Shinanqiao, Tongcheng, Hubei, P R China
| | - Heming Wu
- Hubei Furen Pharmaceutical Corporation Ltd, Shinanqiao, Tongcheng, Hubei, P R China
| | - Wang-Ping Hu
- Department of Pharmacology, Hubei University of Science and Technology, Xianning, Hubei, P R China
- * E-mail:
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63
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Niu KY, Zhang Y, Ro JY. Effects of gonadal hormones on the peripheral cannabinoid receptor 1 (CB1R) system under a myositis condition in rats. Pain 2012; 153:2283-2291. [PMID: 22940464 DOI: 10.1016/j.pain.2012.07.037] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 07/31/2012] [Accepted: 07/31/2012] [Indexed: 10/27/2022]
Abstract
In this study, we assessed the effects of peripherally administered cannabinoids in an orofacial myositis model, and the role of sex hormones in cannabinoid receptor (CBR) expression in trigeminal ganglia (TG). Peripherally administered arachidonylcyclopropylamide (ACPA), a specific CB1R agonist, significantly attenuated complete Freund's adjuvant (CFA)-induced mechanical hypersensitivity in the masseter muscle in male rats. The ACPA effect was blocked by a local administration of AM251, a specific CB1R antagonist, but not by AM630, a specific CB2R antagonist. In female rats, a 30-fold higher dose of ACPA was required to produce a moderate reduction in mechanical hypersensitivity. CFA injected in masseter muscle significantly upregulated CB1R mRNA expression in TG in male, but not in female, rats. There was a close correlation between the CB1R mRNA levels in TG and the antihyperalgesic effect of ACPA. Interleukin (IL)-1β and IL-6, which are elevated in the muscle tissue following CFA treatment, induced a significant upregulation of CB1R mRNA expression in TG from male rats. The upregulation of CB1R was prevented in TG cultures from orchidectomized male rats, which was restored by the application of testosterone. The cytokines did not alter the CB1R mRNA level in TG from intact as well as ovariectomized female rats. Neither estradiol supplement nor estrogen receptor blockade had any effects on CB1R expression. These data indicate that testosterone, but not estradiol, is required for the regulation of CB1Rs in TG under inflammatory conditions, which provide explanations for the sex differences in the antihyperalgesic effects of peripherally administered cannabinoids.
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Affiliation(s)
- Katelyn Y Niu
- Program in Neuroscience, Department of Neural and Pain Sciences, University of Maryland School of Dentistry, Baltimore, MD 21201, USA
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64
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Low brain penetrant CB1 receptor agonists for the treatment of neuropathic pain. Bioorg Med Chem Lett 2012; 22:2932-7. [DOI: 10.1016/j.bmcl.2012.02.048] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 02/15/2012] [Accepted: 02/16/2012] [Indexed: 12/18/2022]
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65
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Valverde O, Torrens M. CB1 receptor-deficient mice as a model for depression. Neuroscience 2012; 204:193-206. [DOI: 10.1016/j.neuroscience.2011.09.031] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 08/31/2011] [Accepted: 09/13/2011] [Indexed: 12/20/2022]
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66
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Cheng YX, Pourashraf M, Luo X, Srivastava S, Walpole C, Salois D, St-Onge S, Payza K, Lessard E, Yu XH, Tomaszewski MJ. γ-Carbolines: a novel class of cannabinoid agonists with high aqueous solubility and restricted CNS penetration. Bioorg Med Chem Lett 2012; 22:1619-24. [PMID: 22284817 DOI: 10.1016/j.bmcl.2011.12.124] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 12/22/2011] [Accepted: 12/27/2011] [Indexed: 01/16/2023]
Abstract
An oral, peripherally restricted CB1/CB2 agonist could provide an interesting approach to treat chronic pain by harnessing the analgesic properties of cannabinoids but without the well-known central side effects. γ-Carbolines are a novel class of potent mixed CB1/CB2 agonists characterized by attractive physicochemical properties including high aqueous solubility. Optimization of the series has led to the discovery of 29, which has oral activity in a rat inflammatory pain model and limited brain exposure at analgesic doses, consistent with a lower risk of CNS-mediated tolerability issues.
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Affiliation(s)
- Yun-Xing Cheng
- Department of Medicinal Chemistry, AstraZeneca R&D Montreal, Saint-Laurent, Quebec, Canada.
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67
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Craft RM, Wakley AA, Tsutsui KT, Laggart JD. Sex differences in cannabinoid 1 vs. cannabinoid 2 receptor-selective antagonism of antinociception produced by delta9-tetrahydrocannabinol and CP55,940 in the rat. J Pharmacol Exp Ther 2011; 340:787-800. [PMID: 22182934 DOI: 10.1124/jpet.111.188540] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The purpose of this study was to determine whether sex differences in cannabinoid (CB)-induced antinociception and motoric effects can be attributed to differential activation of CB(1) or CB(2) receptors. Rats were injected intraperitoneally with vehicle, rimonabant [5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-N-1-piperidinyl-1H-pyrazole-3-carboxamide (SR141716A), a putative CB(1) receptor-selective antagonist; 0.1-10 mg/kg] or 5-(4-chloro-3-methylphenyl)-1-[(4-methylphenyl)methyl]-N-[(1S,2S,4R)-1,3,3-trimethylbicyclo[2.2.1]hept-2-yl]-1H-pyrazole-3-carboxamide (SR144528) (a putative CB(2) receptor-selective antagonist; 1.0-10 mg/kg). Thirty minutes later, Δ(9)-tetrahydrocannabinol (THC; 1.25-40 mg/kg) or 5-(1,1-dimethylheptyl)-2-[5-hydroxy-2-(3-hydroxypropyl)cyclohexyl]phenol (CP55,940) (0.05-1.6 mg/kg) was injected. Paw pressure and tail withdrawal antinociception, locomotor activity, and catalepsy were measured. Rimonabant dose-dependently antagonized THC and CP55,940 in each test, but was up to 10 times more potent in female than male rats on the nociceptive tests; estimates of rimonabant affinity (apparent pK(B)) for the CB(1) receptor were approximately 0.5 to 1 mol/kg higher in female than male rats. SR144528 partially antagonized THC-induced tail withdrawal antinociception and locomotor activity in females, but this antagonism was not dose-dependent or consistent; no SR144528 antagonism was observed in either sex tested with CP55,940. Neither the time course of rimonabant antagonism nor the plasma levels of rimonabant differed between the sexes. Rimonabant and SR144528 did not antagonize morphine-induced antinociception, and naloxone did not antagonize THC-induced antinociception in either sex. These results suggest that THC produces acute antinociceptive and motoric effects via activation of CB(1), and perhaps under some conditions, CB(2) receptors, in female rats, whereas THC acts primarily at CB(1) receptors in male rats. Higher apparent pK(B) for rimonabant in female rats suggests that cannabinoid drugs bind with greater affinity to CB(1) receptors in female than male rats, probably contributing to greater antinociceptive effects observed in female compared with male rats.
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Affiliation(s)
- Rebecca M Craft
- Department of Psychology, Washington State University, Pullman, WA 99164-4820, USA.
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You H, Gadotti VM, Petrov RR, Zamponi GW, Diaz P. Functional characterization and analgesic effects of mixed cannabinoid receptor/T-type channel ligands. Mol Pain 2011; 7:89. [PMID: 22093952 PMCID: PMC3250956 DOI: 10.1186/1744-8069-7-89] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 11/17/2011] [Indexed: 02/06/2023] Open
Abstract
Background Both T-type calcium channels and cannabinoid receptors modulate signalling in the primary afferent pain pathway. Here, we investigate the analgesics activities of a series of novel cannabinoid receptor ligands with T-type calcium channel blocking activity. Results Novel compounds were characterized in radioligand binding assays and in vitro functional assays at human and rat CB1 and CB2 receptors. The inhibitory effects of these compounds on transient expressed human T-type calcium channels were examined in tsA-201 cells using standard whole-cell voltage clamp techniques, and their analgesic effects in response to various administration routes (intrathecally, intraplantarly, intraperitoneally) assessed in the formalin model. A series of compounds were synthesized and evaluated for channel and receptor activity. Compound NMP-7 acted as non-selective CB1/CB2 agonist while NMP4 was found to be a CB1 partial agonist and CB2 inverse agonist. Furthermore, NMP-144 behaved as a selective CB2 inverse agonist. All of these three compounds completely inhibited peak Cav3.2 currents with IC50 values in the low micromolar range. All compounds mediated analgesic effects in the formalin model, but depending on the route of administration, could differentially affect phase 1 and phase 2 of the formalin response. Conclusions Our results reveal that a set of novel cannabinioid receptor ligands potently inhibit T-type calcium channels and show analgesic effects in vivo. Our findings suggest possible novel means of mediating pain relief through mixed T-type/cannabinoid receptor ligands.
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Affiliation(s)
- Haitao You
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
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Ward RJ, Pediani JD, Milligan G. Heteromultimerization of cannabinoid CB(1) receptor and orexin OX(1) receptor generates a unique complex in which both protomers are regulated by orexin A. J Biol Chem 2011; 286:37414-28. [PMID: 21908614 PMCID: PMC3199489 DOI: 10.1074/jbc.m111.287649] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 09/09/2011] [Indexed: 11/06/2022] Open
Abstract
Agonist-induced internalization was observed for both inducible and constitutively expressed forms of the cannabinoid CB(1) receptor. These were also internalized by the peptide orexin A, which has no direct affinity for the cannabinoid CB(1) receptor, but only when the orexin OX(1) receptor was co-expressed along with the cannabinoid CB(1) receptor. This effect of orexin A was concentration-dependent and blocked by OX(1) receptor antagonists. Moreover, the ability of orexin A to internalize the CB(1) receptor was also blocked by CB(1) receptor antagonists. Remarkably, orexin A was substantially more potent in producing internalization of the CB(1) receptor than in causing internalization of the bulk OX(1) receptor population, and this was true in cells in which the CB(1) receptor was maintained at a constant level, whereas levels of OX(1) could be varied and vice versa. Both co-immunoprecipitation and cell surface, homogenous time-resolved fluorescence resonance energy transfer based on covalent labeling of N-terminal "SNAP" and "CLIP" tags present in the extracellular N-terminal domain of the receptors confirmed the capacity of these two receptors to heteromultimerize. These studies confirm the capacity of the CB(1) and OX(1) receptors to interact directly and demonstrate that this complex has unique regulatory characteristics. The higher potency of the agonist orexin A to regulate the CB(1)-OX(1) heteromer compared with the OX(1)-OX(1) homomer present in the same cells and the effects of CB(1) receptor antagonists on the function of orexin A suggest an interplay between these two systems that may modulate appetite, feeding, and wakefulness.
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Affiliation(s)
- Richard J. Ward
- From the Molecular Pharmacology Group, Institute of Neuroscience and Psychology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
| | - John D. Pediani
- From the Molecular Pharmacology Group, Institute of Neuroscience and Psychology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
| | - Graeme Milligan
- From the Molecular Pharmacology Group, Institute of Neuroscience and Psychology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
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Walczak JS, Cervero F. Local activation of cannabinoid CB₁ receptors in the urinary bladder reduces the inflammation-induced sensitization of bladder afferents. Mol Pain 2011; 7:31. [PMID: 21554718 PMCID: PMC3115893 DOI: 10.1186/1744-8069-7-31] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 05/09/2011] [Indexed: 12/17/2022] Open
Abstract
Background Systemic administration of cannabinoid agonists is known to reduce pain induced by bladder inflammation and to modulate cystometric parameters in vivo. We have previously reported that intravesical administration of a cannabinoid agonist reduces the electrical activity of bladder afferents under normal conditions. However, the effects of local activation of bladder cannabinoid receptors on afferent activity during inflammation are unknown. This study was aimed to assess the effects of intravesical administration of a cannabinoid agonist on the discharges of afferent fibers in inflamed bladders ex vivo. We also characterized the expression of CB1 receptors in the bladder and their localization and co-expression with TRPV1, a marker of nociceptive afferents. Results Compared to untreated animals, afferent fiber activity in inflamed bladders was increased for intravesical pressures between 10 and 40 mmHg. Local treatment with a non selective cannabinoid agonist (AZ12646915) significantly reduced the afferent activity at intravesical pressures above 20 mmHg. This effect was blocked by AM251 but not by AM630 (selective for CB1 and CB2 respectively). Finally, CB1 was co-expressed with TRPV1 in control and inflamed bladders. Conclusion These results demonstrate that sensitization of bladder afferents induced by inflammation is partly suppressed by intravesical activation of cannabinoid receptors, an effect that appears to be mediated by CB1 receptors. Also, TRPV1 positive fibers were found to co-express CB1, supporting the hypothesis of a direct action of the cannabinoid agonist on nociceptive afferents. Taken together, these results indicate a peripheral modulation by the cannabinoid system of bladder hypersensitivity during inflammation.
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Affiliation(s)
- Jean-Sébastien Walczak
- McGill University, Anesthesia Research Unit, Faculty of Medicine, Faculty of Dentistry and Alan Edwards Center for Research on Pain, Montréal, Québec, Canada.
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Gutierrez T, Hohmann AG. Cannabinoids for the treatment of neuropathic pain: are they safe and effective? FUTURE NEUROLOGY 2011. [DOI: 10.2217/fnl.11.6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Tannia Gutierrez
- Department of Psychological & Brain Sciences, Indiana University Bloomington, Bloomington, IN 47405-2204, USA
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