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Lefranc F. Transient Receptor Potential (TRP) Ion Channels Involved in Malignant Glioma Cell Death and Therapeutic Perspectives. Front Cell Dev Biol 2021; 9:618961. [PMID: 34458247 PMCID: PMC8388852 DOI: 10.3389/fcell.2021.618961] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 04/29/2021] [Indexed: 01/22/2023] Open
Abstract
Among the most biologically, thus clinically, aggressive primary brain tumors are found malignant gliomas. Despite recent advances in adjuvant therapies, which include targeted and immunotherapies, after surgery and radio/chemotherapy, the tumor is recurrent and always lethal. Malignant gliomas also contain a pool of initiating stem cells that are highly invasive and resistant to conventional treatment. Ion channels and transporters are markedly involved in cancer cell biology, including glioma cell biology. Transient receptor potential (TRP) ion channels are calcium-permeable channels implicated in Ca2+ changes in multiple cellular compartments by modulating the driving force for Ca2+ entry. Recent scientific reports have shown that these channels contribute to the increase in glioblastoma aggressiveness, with glioblastoma representing the ultimate level of glioma malignancy. The current review focuses on each type of TRP ion channel potentially involved in malignant glioma cell death, with the ultimate goal of identifying new therapeutic targets to clinically combat malignant gliomas. It thus appears that cannabidiol targeting the TRPV2 type could be such a potential target.
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Affiliation(s)
- Florence Lefranc
- Department of Neurosurgery, Hôpital Erasme, Université Libre de Bruxelles, Brussels, Belgium
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2
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Jung B, Lee JK, Kim J, Kang EK, Han SY, Lee HY, Choi IS. Synthetic Strategies for (-)-Cannabidiol and Its Structural Analogs. Chem Asian J 2019; 14:3749-3762. [PMID: 31529613 DOI: 10.1002/asia.201901179] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 09/13/2019] [Indexed: 12/14/2022]
Abstract
(-)-Cannabidiol ((-)-CBD), a non-psychoactive phytocannabinoid from Cannabis, and its structural analogs have received growing attention in recent years because of their potential therapeutic benefits, including neuroprotective, anti-epileptic, anti-inflammatory, anxiolytic, and anti-cancer properties. (-)-CBD and its analogs have been obtained mainly based on extraction from the natural source; however, the conventional extraction-based methods have some drawbacks, such as poor quality control along with purification difficulty. Chemical-synthetic strategies for (-)-CBD could tackle these issues, and, additionally, generate novel (-)-CBD analogs that exhibit advanced biological activities. This review concisely summarizes the historic and recent milestones in the synthetic strategies for (-)-CBD and its analogs.
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Affiliation(s)
| | - Jungkyu K Lee
- Department of Chemistry, Green-Nano Materials Research Center, Kyungpook National University, Daegu, 41566, Korea
| | - Jungnam Kim
- Department of Chemistry, KAIST, Daejeon, 34141, Korea
| | - Eunhye K Kang
- Department of Chemistry, KAIST, Daejeon, 34141, Korea
| | | | - Hee-Yoon Lee
- Department of Chemistry, KAIST, Daejeon, 34141, Korea
| | - Insung S Choi
- Department of Chemistry, KAIST, Daejeon, 34141, Korea
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3
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Schonhofen P, Bristot IJ, Crippa JA, Hallak JEC, Zuardi AW, Parsons RB, Klamt F. Cannabinoid-Based Therapies and Brain Development: Potential Harmful Effect of Early Modulation of the Endocannabinoid System. CNS Drugs 2018; 32:697-712. [PMID: 30109642 DOI: 10.1007/s40263-018-0550-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The endocannabinoid retrograde signaling pathway is widely expressed in the central nervous system, where it plays major roles in regulating synaptic plasticity (excitatory and inhibitory) through long-term potentiation and long-term depression. The endocannabinoid system (ECS) components-cannabinoid receptors, endocannabinoids and synthesis/degradation enzymes-are expressed and are functional from early developmental stages and throughout adolescent cortical development, regulating progenitor cell fate, neural differentiation, migration and survival. This may potentially confer increased vulnerability to adverse outcomes from early cannabinoid exposure. Cannabidiol (CBD) is one of the most studied exogenous cannabinoids, and CBD-enriched Cannabis extracts have been widely (and successfully) used as adjuvants to treat children with refractory epilepsy, and there is even a Food and Drug Administration (FDA)-approved drug with purified CBD derived from Cannabis. However, there is insufficient information on possible long-term changes in the central nervous system caused by cannabinoid treatments during early childhood. Like the majority of cannabinoids, CBD is able to exert its effects directly and indirectly through the ECS, which can perturb the regulatory processes mediated by this system. In addition, CBD has a large number of non-endocannabinoid targets, which can explain CBD's effects. Here, we review the current knowledge about CBD-based therapies-pure and CBD-enriched Cannabis extracts-in studies with pediatric patients, their side effects, and their mechanisms of action regarding the central nervous system and neurodevelopment aspects. Since Cannabis extracts contain Δ9-tetrahydrocannabinol (Δ9-THC), we consider that pure CBD is possibly safer for young patients. Nevertheless, CBD, as well as other natural and/or synthetic cannabinoids, should be studied in more detail as a therapeutic alternative to CBD-enriched Cannabis extracts for young patients.
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Affiliation(s)
- Patrícia Schonhofen
- Laboratory of Cellular Biochemistry, Department of Biochemistry, ICBS/UFRGS, 2600 Ramiro Barcelos St, Porto Alegre, RS, 90035-003, Brazil
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, ICBS/UFRGS, Porto Alegre, RS, 90035-003, Brazil
- National Institutes of Science and Technology-Translational Medicine (INCT-TM), Porto Alegre, Brazil
| | - Ivi Juliana Bristot
- Laboratory of Cellular Biochemistry, Department of Biochemistry, ICBS/UFRGS, 2600 Ramiro Barcelos St, Porto Alegre, RS, 90035-003, Brazil
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, ICBS/UFRGS, Porto Alegre, RS, 90035-003, Brazil
- National Institutes of Science and Technology-Translational Medicine (INCT-TM), Porto Alegre, Brazil
| | - José Alexandre Crippa
- National Institutes of Science and Technology-Translational Medicine (INCT-TM), Porto Alegre, Brazil
- Neuroscience and Behavior Department, Faculty of Medicine of Ribeirão Preto, Ribeirão Preto, SP, Brazil
| | - Jaime Eduardo Cecílio Hallak
- National Institutes of Science and Technology-Translational Medicine (INCT-TM), Porto Alegre, Brazil
- Neuroscience and Behavior Department, Faculty of Medicine of Ribeirão Preto, Ribeirão Preto, SP, Brazil
| | - Antônio Waldo Zuardi
- National Institutes of Science and Technology-Translational Medicine (INCT-TM), Porto Alegre, Brazil
- Neuroscience and Behavior Department, Faculty of Medicine of Ribeirão Preto, Ribeirão Preto, SP, Brazil
| | - Richard B Parsons
- Institute of Pharmaceutical Science, King's College London (KCL), London, SE1 9NH, UK
| | - Fábio Klamt
- Laboratory of Cellular Biochemistry, Department of Biochemistry, ICBS/UFRGS, 2600 Ramiro Barcelos St, Porto Alegre, RS, 90035-003, Brazil.
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, ICBS/UFRGS, Porto Alegre, RS, 90035-003, Brazil.
- National Institutes of Science and Technology-Translational Medicine (INCT-TM), Porto Alegre, Brazil.
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4
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Myers AM, Siegele PB, Foss JD, Tuma RF, Ward SJ. Single and combined effects of plant-derived and synthetic cannabinoids on cognition and cannabinoid-associated withdrawal signs in mice. Br J Pharmacol 2018; 176:1552-1567. [PMID: 29338068 DOI: 10.1111/bph.14147] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 10/04/2017] [Accepted: 10/11/2017] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND AND PURPOSE It has been suggested that the non-euphorogenic phytocannabinoid cannabidiol (CBD) can ameliorate adverse effects of Δ9 -tetrahydrocannabinol (THC). We determined whether CBD ameliorates cognitive deficits and withdrawal signs induced by cannabinoid CB1 /CB2 receptor agonists or produces these pharmacological effects on its own. EXPERIMENTAL APPROACH The effects of THC or the CB1 /CB2 receptor full agonist WIN55212 alone, CBD alone or their combination were tested across a range of doses. Cognitive effects were assessed in C57BL/6 mice in a conditional discrimination task and in the Barnes maze. Cannabinoid withdrawal signs were assessed following precipitated withdrawal by acute administration of the CB1 receptor antagonist SR141716, the 5-HT1A receptor antagonist WAY100635, the TRPV1 receptor antagonist capsazepine or the adenosine A2A receptor antagonist SCH58261. KEY RESULTS THC produced significant motor and cognitive impairment in the Barnes maze task, none of which were attenuated by the addition of CBD. CBD alone did not affect cognitive performance. Precipitation of withdrawal signs by SR141716 occurred in mice chronically treated with THC or WIN55,212. These withdrawal signs were not attenuated by addition of chronic CBD. Chronic treatment with CBD alone did not induce withdrawal signs precipitated by SR141716 or WAY100635. Chronic CBD treatment also produced anxiolysis, which was not altered by attempting to precipitate withdrawal-induced anxiety with a range of antagonists. CONCLUSIONS AND IMPLICATIONS CBD as a monotherapy may prove to be a safer pharmacological agent, than CB1 receptor agonists alone or in combination with CBD, for the treatment of several disorders. LINKED ARTICLES This article is part of a themed section on 8th European Workshop on Cannabinoid Research. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.10/issuetoc.
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Affiliation(s)
- Alyssa M Myers
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
| | - Patrick B Siegele
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
| | - Jeffrey D Foss
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
| | - Ronald F Tuma
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
| | - Sara Jane Ward
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
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Abstract
A major factor associated with poor prognostic outcome after a first psychotic break is cannabis misuse, which is prevalent in schizophrenia and particularly common in individuals with recent-onset psychosis. Behavioral interventions aimed at reducing cannabis use have been unsuccessful in this population. Cannabidiol (CBD) is a phytocannabinoid found in cannabis, although at low concentrations in modern-day strains. CBD has a broad pharmacological profile, but contrary to ∆9-tetrahydrocannabinol (THC), CBD does not activate CB1 or CB2 receptors and has at most subtle subjective effects. Growing evidence indicates that CBD acts as an antipsychotic and anxiolytic, and several reports suggest neuroprotective effects. Moreover, CBD attenuates THC's detrimental effects, both acutely and chronically, including psychotogenic, anxiogenic, and deleterious cognitive effects. This suggests that CBD may improve the disease trajectory of individuals with early psychosis and comorbid cannabis misuse in particular-a population with currently poor prognostic outcome and no specialized effective intervention.
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Affiliation(s)
- Britta Hahn
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD,To whom correspondence should be addressed; tel: 001-410-402-6112, fax: 001-410-402-7198, e-mail:
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6
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Morales P, Reggio PH, Jagerovic N. An Overview on Medicinal Chemistry of Synthetic and Natural Derivatives of Cannabidiol. Front Pharmacol 2017; 8:422. [PMID: 28701957 PMCID: PMC5487438 DOI: 10.3389/fphar.2017.00422] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 06/14/2017] [Indexed: 12/12/2022] Open
Abstract
Cannabidiol (CBD) has been traditionally used in Cannabis-based preparation, however historically, it has received far less interest as a single drug than the other components of Cannabis. Currently, CBD generates considerable interest due to its beneficial neuroprotective, antiepileptic, anxiolytic, antipsychotic, and anti-inflammatory properties. Therefore, the CBD scaffold becomes of increasing interest for medicinal chemists. This review provides an overview of the chemical structure of natural and synthetic CBD derivatives including the molecular targets associated with these compounds. A clear identification of their biological targets has been shown to be still very challenging.
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Affiliation(s)
- Paula Morales
- Department of Chemistry and Biochemistry, University of North Carolina Greensboro, GreensboroNC, United States
| | - Patricia H. Reggio
- Department of Chemistry and Biochemistry, University of North Carolina Greensboro, GreensboroNC, United States
| | - Nadine Jagerovic
- Instituto de Química Médica, Consejo Superior de Investigaciones Científicas, Unidad Asociada I+D+i al Instituto de Química Médica/Universidad Rey Juan CarlosMadrid, Spain
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Mori MA, Meyer E, Soares LM, Milani H, Guimarães FS, de Oliveira RMW. Cannabidiol reduces neuroinflammation and promotes neuroplasticity and functional recovery after brain ischemia. Prog Neuropsychopharmacol Biol Psychiatry 2017; 75:94-105. [PMID: 27889412 DOI: 10.1016/j.pnpbp.2016.11.005] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 11/22/2016] [Indexed: 11/30/2022]
Abstract
This study investigated the effects of cannabidiol (CBD), a non-psychotomimetic phytochemical present in Cannabis sativa, on the cognitive and emotional impairments induced by bilateral common carotid artery occlusion (BCCAO) in mice. Using a multi-tiered behavioral testing battery during 21days, we found that BCCAO mice exhibited long-lasting functional deficits reflected by increase in anxiety-like behavior (day 9), memory impairments (days 12-18) and despair-like behavior (day 21). Short-term CBD 10mg/kg treatment prevented the cognitive and emotional impairments, attenuated hippocampal neurodegeneration and white matter (WM) injury, and reduced glial response that were induced by BCCAO. In addition, ischemic mice treated with CBD exhibited an increase in the hippocampal brain derived neurotrophic factor (BDNF) protein levels. CBD also stimulated neurogenesis and promoted dendritic restructuring in the hippocampus of BCCAO animals. Collectively, the present results demonstrate that short-term CBD treatment results in global functional recovery in ischemic mice and impacts multiple and distinct targets involved in the pathophysiology of brain ischemic injury.
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Affiliation(s)
- Marco Aurélio Mori
- Department of Pharmacology and Therapeutics, State University of Maringá, Av. Colombo, 5790, 87020-900 Maringá, Paraná, Brazil
| | - Erika Meyer
- Department of Pharmacology and Therapeutics, State University of Maringá, Av. Colombo, 5790, 87020-900 Maringá, Paraná, Brazil
| | - Ligia Mendes Soares
- Department of Pharmacology and Therapeutics, State University of Maringá, Av. Colombo, 5790, 87020-900 Maringá, Paraná, Brazil
| | - Humberto Milani
- Department of Pharmacology and Therapeutics, State University of Maringá, Av. Colombo, 5790, 87020-900 Maringá, Paraná, Brazil
| | - Francisco Silveira Guimarães
- Department of Pharmacology, School of Medicine, USP, Av. Bandeirantes, 14015-000 Ribeirão Preto, São Paulo, Brazil
| | - Rúbia Maria Weffort de Oliveira
- Department of Pharmacology and Therapeutics, State University of Maringá, Av. Colombo, 5790, 87020-900 Maringá, Paraná, Brazil.
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8
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Cascio MG, Gauson LA, Stevenson LA, Ross RA, Pertwee RG. Evidence that the plant cannabinoid cannabigerol is a highly potent alpha2-adrenoceptor agonist and moderately potent 5HT1A receptor antagonist. Br J Pharmacol 2009; 159:129-41. [PMID: 20002104 DOI: 10.1111/j.1476-5381.2009.00515.x] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Cannabis is the source of at least seventy phytocannabinoids. The pharmacology of most of these has been little investigated, three notable exceptions being Delta(9)-tetrahydrocannabinol, cannabidiol and Delta(9)-tetrahydrocannabivarin. This investigation addressed the question of whether the little-studied phytocannabinoid, cannabigerol, can activate or block any G protein-coupled receptor. EXPERIMENTAL APPROACH The [(35)S]GTPgammaS binding assay, performed with mouse brain membranes, was used to test the ability of cannabigerol to produce G protein-coupled receptor activation or blockade. Its ability to displace [(3)H]CP55940 from mouse CB(1) and human CB(2) cannabinoid receptors and to inhibit electrically evoked contractions of the mouse isolated vas deferens was also investigated. KEY RESULTS In the brain membrane experiments, cannabigerol behaved as a potent alpha(2)-adrenoceptor agonist (EC(50)= 0.2 nM) and antagonized the 5-HT(1A) receptor agonist, R-(+)-8-hydroxy-2-(di-n-propylamino)tetralin (apparent K(B)= 51.9 nM). At 10 microM, it also behaved as a CB(1) receptor competitive antagonist. Additionally, cannabigerol inhibited evoked contractions of the vas deferens in a manner that appeared to be alpha(2)-adrenoceptor-mediated (EC(50)= 72.8 nM) and displayed significant affinity for mouse CB(1) and human CB(2) receptors. CONCLUSIONS AND IMPLICATIONS This investigation has provided the first evidence that cannabigerol can activate alpha(2)-adrenoceptors, bind to cannabinoid CB(1) and CB(2) receptors and block CB(1) and 5-HT(1A) receptors. It will now be important to investigate why cannabigerol produced signs of agonism more potently in the [(35)S]GTPgammaS binding assay than in the vas deferens and also whether it can inhibit noradrenaline uptake in this isolated tissue and in the brain.
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Affiliation(s)
- M G Cascio
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK
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Pierantoni R, Cobellis G, Meccariello R, Cacciola G, Chianese R, Chioccarelli T, Fasano S. CB1 activity in male reproduction: mammalian and nonmammalian animal models. VITAMINS AND HORMONES 2009; 81:367-87. [PMID: 19647119 DOI: 10.1016/s0083-6729(09)81014-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The importance of the endocannabinoid system (ECBS) and its involvement in several physiological processes is still increasing. Since the isolation of the main active compound of Cannabis sativa, Delta(9)-THC, several lines of research have evidenced the basic roles of this signaling system mainly considering its high conservation during evolution. In this chapter the attention is focussed on the involvement of the ECBS in the control of male reproductive aspects at both central and local levels which are both considered from a comparative point of view.
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Affiliation(s)
- Riccardo Pierantoni
- Dipartimento di Medicina Sperimentale, Seconda Università di Napoli, Via Costantinopoli, Napoli, Italy
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10
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Durst R, Danenberg H, Gallily R, Mechoulam R, Meir K, Grad E, Beeri R, Pugatsch T, Tarsish E, Lotan C. Cannabidiol, a nonpsychoactive Cannabis constituent, protects against myocardial ischemic reperfusion injury. Am J Physiol Heart Circ Physiol 2007; 293:H3602-7. [PMID: 17890433 DOI: 10.1152/ajpheart.00098.2007] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cannabidiol (CBD) is a major, nonpsychoactive Cannabis constituent with anti-inflammatory activity mediated by enhancing adenosine signaling. Inasmuch as adenosine receptors are promising pharmaceutical targets for ischemic heart diseases, we tested the effect of CBD on ischemic rat hearts. For the in vivo studies, the left anterior descending coronary artery was transiently ligated for 30 min, and the rats were treated for 7 days with CBD (5 mg/kg ip) or vehicle. Cardiac function was studied by echocardiography. Infarcts were examined morphometrically and histologically. For ex vivo evaluation, CBD was administered 24 and 1 h before the animals were killed, and hearts were harvested for physiological measurements. In vivo studies showed preservation of shortening fraction in CBD-treated animals: from 48 +/- 8 to 39 +/- 8% and from 44 +/- 5 to 32 +/- 9% in CBD-treated and control rats, respectively (n = 14, P < 0.05). Infarct size was reduced by 66% in CBD-treated animals, despite nearly identical areas at risk (9.6 +/- 3.9 and 28.2 +/- 7.0% in CBD and controls, respectively, P < 0.001) and granulation tissue proportion as assessed qualitatively. Infarcts in CBD-treated animals were associated with reduced myocardial inflammation and reduced IL-6 levels (254 +/- 22 and 2,812 +/- 500 pg/ml in CBD and control rats, respectively, P < 0.01). In isolated hearts, no significant difference in infarct size, left ventricular developed pressures during ischemia and reperfusion, or coronary flow could be detected between CBD-treated and control hearts. Our study shows that CBD induces a substantial in vivo cardioprotective effect from ischemia that is not observed ex vivo. Inasmuch as CBD has previously been administered to humans without causing side effects, it may represent a promising novel treatment for myocardial ischemia.
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Affiliation(s)
- Ronen Durst
- Cardiology Department, Hadassah Hebrew University Medical Center, Jerusalem, Israel.
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11
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Gehani NC, Nalwalk JW, Razdan RK, Martin BR, Sun X, Wentland M, Abood ME, Hough LB. Significance of cannabinoid CB1 receptors in improgan antinociception. THE JOURNAL OF PAIN 2007; 8:850-60. [PMID: 17644043 PMCID: PMC2185743 DOI: 10.1016/j.jpain.2007.05.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2006] [Revised: 04/24/2007] [Accepted: 05/25/2007] [Indexed: 11/23/2022]
Abstract
UNLABELLED Improgan is a congener of the H(2) antagonist cimetidine, which produces potent antinociception. Because a) the mechanism of action of improgan remains unknown and b) this drug may indirectly activate cannabinoid CB(1) receptors, the effects of the CB(1) antagonist/inverse agonist rimonabant (SR141716A) and 3 congeners with varying CB(1) potencies were studied on improgan antinociception after intracerebroventricular (icv) dosing in rats. Consistent with blockade of brain CB(1) receptors, rimonabant (K(d) = 0.23 nM), and O-1691 (K(d) = 0.22 nM) inhibited improgan antinociception by 48% and 70% after icv doses of 43 nmol and 25 nmol, respectively. However, 2 other derivatives with much lower CB(1) affinity (O-1876, K(d) = 139 nM and O-848, K(d) = 352 nM) unexpectedly blocked improgan antinociception by 65% and 50% after icv doses of 300 nmol and 30 nmol, respectively. These derivatives have 600-fold to 1500-fold lower CB(1) potencies than that of rimonabant, yet they retained improgan antagonist activity in vivo. In vitro dose-response curves with (35)S-GTPgammaS on CB(1) receptor-containing membranes confirmed the approximate relative potency of the derivatives at the CB(1) receptor. Although antagonism of improgan antinociception by rimonabant has previously implicated a mechanistic role for the CB(1) receptor, current findings with rimonabant congeners suggest that receptors other than, or in addition to CB(1) may participate in the pain-relieving mechanisms activated by this drug. The use of congeners such as O-848, which lack relevant CB(1)-blocking properties, will help to identify these cannabinoid-like, non-CB(1) mechanisms. PERSPECTIVE This article describes new pharmacological characteristics of improgan, a pain-relieving drug that acts by an unknown mechanism. Improgan may use a marijuana-like (cannabinoid) pain-relieving mechanism, but it is shown presently that the principal cannabinoid receptor in the brain (CB(1)) is not solely responsible for improgan analgesia.
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MESH Headings
- Analgesics/administration & dosage
- Analysis of Variance
- Animals
- Cimetidine/administration & dosage
- Cimetidine/analogs & derivatives
- Cimetidine/chemistry
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Guanosine 5'-O-(3-Thiotriphosphate)/metabolism
- Injections, Intraventricular/methods
- Male
- Pain/drug therapy
- Pain Measurement/methods
- Pain Threshold/drug effects
- Piperidines/administration & dosage
- Piperidines/chemistry
- Pyrazoles/administration & dosage
- Pyrazoles/chemistry
- Rats
- Rats, Sprague-Dawley
- Reaction Time/drug effects
- Receptor, Cannabinoid, CB1/agonists
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptor, Cannabinoid, CB1/physiology
- Rimonabant
- Time Factors
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Affiliation(s)
- Neal C Gehani
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, New York 12208, USA
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12
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McPartland JM, Glass M, Pertwee RG. Meta-analysis of cannabinoid ligand binding affinity and receptor distribution: interspecies differences. Br J Pharmacol 2007; 152:583-93. [PMID: 17641667 PMCID: PMC2190026 DOI: 10.1038/sj.bjp.0707399] [Citation(s) in RCA: 171] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
A meta-analysis, unlike a literature review, synthesizes previous studies into new results. Pooled data from 211 studies measured ligand binding affinities at human (Hs) or rat (Rn) cannabinoid receptors CB1 and CB2. Cochrane methods were modified for this non-clinical analysis. Meta-regression detected data heterogeneity arising from methodological factors: use of sectioned tissues, lack of PMSF and choice of radioligand. Native brain tissues exhibited greater affinity (lower nM) than transfected cells, but the trend fell short of significance, as did the trend between centrifugation and filtration methods. Correcting for heterogeneity, mean Ki values for delta 9-tetrahydrocannabinol differed significantly between HsCB1 and RnCB1 (25.1 and 42.6 nM, respectively) but not between HsCB1 and HsCB2 (25.1 and 35.2). Mean Kd values for HsCB1, RnCB1 and HsCB2 of CP55,940 (2.5, 0.98, 0.92) and WIN55,212-2 (16.7, 2.4, 3.7) differed between HsCB1 and RnCB1 and between HsCB1 and HsCB2. SR141716A differed between HsCB1 and RnCB1 (2.9 and 1.0 nM). Anandamide at HsCB1, RnCB1 and HsCB2 (239.2, 87.7, 439.5) fell short of statistical differences due to heterogeneity. We consider these Kd and Ki values to be the most valid estimates in the literature. Sensitivity analyses did not support the numerical validity of cannabidiol, cannabinol, 2-arachidonoyl glycerol and all ligands at RnCB2. Aggregate rank order analysis of CB(1) distribution in the brain (pooled from 119 autoradiographic, immunohistochemical and in situ hybridization studies) showed denser HsCB1 expression in cognitive regions (cerebral cortex) compared to RnCB1, which was relatively richer in movement-associated areas (cerebellum, caudate-putamen). Implications of interspecies differences are discussed.
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Affiliation(s)
- J M McPartland
- Department of Molecular Biology, GW Pharmaceuticals, Salisbury, Wiltshire, UK.
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13
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Ryan D, Drysdale AJ, Pertwee RG, Platt B. Interactions of cannabidiol with endocannabinoid signalling in hippocampal tissue. Eur J Neurosci 2007; 25:2093-102. [PMID: 17419758 DOI: 10.1111/j.1460-9568.2007.05448.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The phytocannabinoid cannabidiol (CBD) possesses no psychotropic activity amid potentially beneficial therapeutic applications. We here characterized interactions between CBD (1 microM) and the endocannabinoid system in cultured rat hippocampal cells. The CBD-induced Ca2+ rise observed in neurons and glia was markedly reduced in the presence of the endogenous cannabinoid anandamide in neurons, with no alteration seen in glia. Neuronal CBD responses were even more reduced in the presence of the more abundant endocannabinoid 2-arachidonyl glycerol, this action was maintained in the presence of the CB1 receptor antagonist AM281 (100 nM). Neuronal CBD responses were also reduced by pre-exposure to glutamate, expected to increase endocannabinoid levels by increasing in [Ca2+]i. Application of AM281 at 1 microM elevated CBD-induced Ca2+ responses in both cell types, further confirming our finding that endocannabinoid-mediated signalling is negatively coupled to the action of CBD. However, upregulation of endogenous levels of endocannabinoids via inhibition of endocannabinoid hydrolysis (with URB597 and MAFP) could not be achieved under resting conditions. Because delta9-tetrahydrocannabinol did not mimic the endocannabinoid actions, and pertussis toxin treatment had no effect on CBD responses, we propose that the effects of AM281 were mediated via a constitutively active signalling pathway independent of CB1 signalling. Instead, signalling via G(q/11) and phospholipase C appears to be negatively coupled to CBD-induced Ca2+ responses, as the inhibitor U73122 enhanced CBD responses. Our data highlight the interaction between exogenous and endogenous cannabinoid signalling, and provide evidence for the presence of an additional pharmacological target, sensitive to endocannabinoids and to AM281.
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Affiliation(s)
- Duncan Ryan
- School of Medical Sciences, College of Life Sciences and Medicine, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD Scotland, UK
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Thomas A, Baillie GL, Phillips AM, Razdan RK, Ross RA, Pertwee RG. Cannabidiol displays unexpectedly high potency as an antagonist of CB1 and CB2 receptor agonists in vitro. Br J Pharmacol 2007; 150:613-23. [PMID: 17245363 PMCID: PMC2189767 DOI: 10.1038/sj.bjp.0707133] [Citation(s) in RCA: 528] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND AND PURPOSE A nonpsychoactive constituent of the cannabis plant, cannabidiol has been demonstrated to have low affinity for both cannabinoid CB1 and CB2 receptors. We have shown previously that cannabidiol can enhance electrically evoked contractions of the mouse vas deferens, suggestive of inverse agonism. We have also shown that cannabidiol can antagonize cannabinoid receptor agonists in this tissue with a greater potency than we would expect from its poor affinity for cannabinoid receptors. This study aimed to investigate whether these properties of cannabidiol extend to CB1 receptors expressed in mouse brain and to human CB2 receptors that have been transfected into CHO cells. EXPERIMENTAL APPROACH The [35S]GTPS binding assay was used to determine both the efficacy of cannabidiol and the ability of cannabidiol to antagonize cannabinoid receptor agonists (CP55940 and R-(+)-WIN55212) at the mouse CB1 and the human CB2 receptor. KEY RESULTS This paper reports firstly that cannabidiol displays inverse agonism at the human CB2 receptor. Secondly, we demonstrate that cannabidiol is a high potency antagonist of cannabinoid receptor agonists in mouse brain and in membranes from CHO cells transfected with human CB2 receptors. CONCLUSIONS AND IMPLICATIONS This study has provided the first evidence that cannabidiol can display CB2 receptor inverse agonism, an action that appears to be responsible for its antagonism of CP55940 at the human CB2 receptor. The ability of cannabidiol to behave as a CB2 receptor inverse agonist may contribute to its documented anti-inflammatory properties.
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Affiliation(s)
- A Thomas
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK.
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15
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Ryan D, Drysdale AJ, Pertwee RG, Platt B. Differential effects of cannabis extracts and pure plant cannabinoids on hippocampal neurones and glia. Neurosci Lett 2006; 408:236-41. [PMID: 16997463 DOI: 10.1016/j.neulet.2006.09.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2006] [Revised: 06/16/2006] [Accepted: 09/05/2006] [Indexed: 10/24/2022]
Abstract
We have shown previously that the plant cannabinoid cannabidiol (CBD) elevates intracellular calcium levels in both cultured hippocampal neurones and glia. Here, we investigated whether the main psychotropic constituent of cannabis, Delta(9)-tetrahydrocannabinol (THC) alone or in combination with other cannabis constituents can cause similar responses, and whether THC affects the responses induced by CBD. Our experiments were performed with 1 microM pure THC (pTHC), with 1 microM pure CBD (pCBD), with a high-THC, low CBD cannabis extract (eTHC), with a high-CBD, low THC cannabis extract (eCBD), with a mixture of eTHC and eCBD (THC:CBD=1:1) or with corresponding 'mock extracts' that contained only pTHC and pCBD mixed in the same proportion as in eTHC, eCBD or the 1:1 mixture of eTHC and eCBD. We detected significant differences in neurones both between the effects of pTHC and eTHC and between the effects of pCBD and eCBD. There were also differences between the Ca(2+) responses evoked in both neurones and glia by eTHC and mock eTHC, but not between eCBD and mock eCBD. A particularly striking observation was the much increased response size and maximal responder rates induced by the mixture of eTHC and eCBD than by the corresponding 1:1 mixture of pTHC and pCBD. Our data suggest that THC shares the ability of CBD to elevate Ca(2+) levels in neurones and glia, that THC and CBD interact synergistically and that the cannabis extracts have other constituents yet to be identified that can significantly modulate the ability of THC and CBD to raise Ca(2+) levels.
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Affiliation(s)
- Duncan Ryan
- School of Medical Sciences, College of Life Sciences and Medicine, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, Scotland, UK
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Nalwalk JW, Svokos K, Hough LB. Cannabinoid-improgan cross-tolerance: Improgan is a cannabinomimetic analgesic lacking affinity at the cannabinoid CB1 receptor. Eur J Pharmacol 2006; 549:79-83. [PMID: 16989809 DOI: 10.1016/j.ejphar.2006.08.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2006] [Revised: 08/04/2006] [Accepted: 08/14/2006] [Indexed: 10/24/2022]
Abstract
Improgan is a non-opioid analgesic which does not act at known histamine or cannabinoid receptors. Because improgan antinociception is blocked by low doses of a cannabinoid CB1 antagonist, the present experiments determined if development of cannabinoid tolerance in mice would alter improgan antinociception. Twice-daily injections of Delta9-tetrahydrocannabinol (THC, 10 mg/kg, s.c.) for 3.5 days induced 47-54% and 42-56% reductions in cannabinoid (WIN 55,212-2, 20 microg, i.c.v.) and improgan (30 microg, i.c.v.) antinociception, respectively, as compared with responses from vehicle-treated groups. Because improgan lacks cannabinoid-like side effects in rats, and does not act directly on cannabinoid CB1 receptors, the finding that development of cannabinoid tolerance reduces improgan antinociception suggests that this drug may release endocannabinoids, or activate novel cannabinoid sites. Either possibility offers the potential for developing new types of analgesics.
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Affiliation(s)
- Julia W Nalwalk
- Center for Neuropharmacology and Neuroscience, Albany Medical College MC-136, Albany, NY 12208, USA
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Fadda P, Robinson L, Fratta W, Pertwee RG, Riedel G. Scopolamine and MK801-induced working memory deficits in rats are not reversed by CBD-rich cannabis extracts. Behav Brain Res 2006; 168:307-11. [PMID: 16406104 DOI: 10.1016/j.bbr.2005.11.022] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2005] [Revised: 11/15/2005] [Accepted: 11/21/2005] [Indexed: 11/27/2022]
Abstract
Smoking marijuana causes working and short-term memory deficits, an effect that is mediated by cannabinoid receptor (CB1) activation in the brain. While this may be due to the main psychoactive constituent Delta9-tetrahydrocannabinol (Delta9-THC), plant extracts also contain other cannabinoid and terpenoid compounds with unknown properties. Towards this end, we have recently shown that high concentrations of plant extracts rich in cannabidiol (CBD) can reverse working memory deficits induced by Delta9-THC which is a remaining contaminant of this extract [Fadda P, Robinson L, Fratta W, Pertwee RG, Riedel G. Differential effects of THC- and CBD-rich cannabis-extracts on working memory in rats. Neuropahrmacology 2004;47:1170-9]. Since this effect was dose-dependent and indicative of memory enhancing qualities of the CBD-rich extract, this prompted a wider investigation into the effects of CBD on other forms of amnesia in order to determine the mechanism of action and to reveal its potency against anticholinergic and antiglutamatergic agents. We employed a spatial delayed matching to position task in the open-field water maze. Both scopolamine (0.2 mg/kg i.p.) and dizocilpine (MK801: 0.1mg/kg i.p.) impaired working memory at delays of 30 s and 4 h. Two doses of CBD-rich extracts (5 and 10 mg/kg), which did not affect working memory when given alone, were unable to reverse these deficits when co-administered with scopolamine or MK801. These data suggest that reversal of working memory deficits by CBD-rich extracts are specific to the cannabinoid system and do not compensate for acutely induced cholinergic or glutamatergic receptor hypoactivity.
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Affiliation(s)
- Paola Fadda
- School of Medical Sciences, College of Life Sciences and Medicine, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
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18
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Abstract
Mammalian tissues express at least two cannabinoid receptor types, CB1 and CB2, both G protein coupled. CB1 receptors are found predominantly at nerve terminals where they mediate inhibition of transmitter release. CB2 receptors occur mainly on immune cells, one of their roles being to modulate cytokine release. Endogenous agonists for cannabinoid receptors also exist, and are all eicosanoids. The first-discovered of these 'endocannabinoids' was arachidonoylethanolamide and there is convincing evidence that this ligand and some of its metabolites can activate vanilloid VRI (TRPV1) receptors. Certain cannabinoids also appear to have TRPV1-like and/or non-CB1, non-CB2, non-TRPV1 targets. Several CB1- and CB2-selective agonists and antagonists have been developed. Antagonists include the CB1-selective SR141716A, AM251, AM281 and LY320135, and the CB2-selective SR144528 and AM630. These all behave as inverse agonists, one indication that CB1 and CB2 receptors can exist in a constitutively active state. 'Neutral' cannabinoid receptor antagonists have also been developed. CB1 and/or CB2 receptor activation appears to ameliorate inflammatory and neuropathic pain and certain multiple sclerosis symptoms. This might be exploited clinically by using CB1, CB2 or CB1/CB2 agonists, or inhibitors of the membrane transport or catabolism of endocannabinoids that are released in increased amounts, at least in animal models of pain and multiple sclerosis. We have recently discovered the presence of an allosteric site on the CB1 receptor. Consequently, it may also prove possible to enhance 'autoprotective' effects of released endocannabinoids with CB1 allosteric enhancers or, indeed, to reduce proposed 'autoimpairing' effects of released endocannabinoids such as excessive food intake with CB1 allosteric antagonists.
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Affiliation(s)
- R G Pertwee
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, Scotland, UK.
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Kogan NM, Blázquez C, Alvarez L, Gallily R, Schlesinger M, Guzmán M, Mechoulam R. A cannabinoid quinone inhibits angiogenesis by targeting vascular endothelial cells. Mol Pharmacol 2006; 70:51-9. [PMID: 16571653 DOI: 10.1124/mol.105.021089] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recent findings on the inhibition of angiogenesis and vascular endothelial cell proliferation by anthracycline antibiotics, which contain a quinone moiety, make this type of compound a very promising lead in cancer research/therapy. We have reported that a new cannabinoid anticancer quinone, cannabidiol hydroxyquinone (HU-331), is highly effective against tumor xenografts in nude mice. For evaluation of the antiangiogenic action of cannabinoid quinones, collagen-embedded rat aortic ring assay was used. The ability of cannabinoids to cause endothelial cell apoptosis was assayed by TUNEL staining and flow cytometry analysis. To examine the genes and pathways targeted by HU-331 in vascular endothelial cells, human cDNA microarrays and polymerase chain reaction were used. Immunostaining with anti-CD31 of tumors grown in nude mice served to indicate inhibition of tumor angiogenesis. HU-331 was found to be strongly antiangiogenic, significantly inhibiting angiogenesis at concentrations as low as 300 nM. HU-331 inhibited angiogenesis by directly inducing apoptosis of vascular endothelial cells without changing the expression of pro- and antiangiogenic cytokines and their receptors. A significant decrease in the total area occupied by vessels in HU-331-treated tumors was also observed. These data lead us to consider HU-331 to have high potential as a new antiangiogenic and anticancer drug.
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Affiliation(s)
- Natalya M Kogan
- Department of Medicinal Chemistry and Natural Products, Medical Faculty, The Hebrew University, Jerusalem 91120, Israel.
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Thomas A, Stevenson LA, Wease KN, Price MR, Baillie G, Ross RA, Pertwee RG. Evidence that the plant cannabinoid Delta9-tetrahydrocannabivarin is a cannabinoid CB1 and CB2 receptor antagonist. Br J Pharmacol 2006; 146:917-26. [PMID: 16205722 PMCID: PMC1751228 DOI: 10.1038/sj.bjp.0706414] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Delta9-tetrahydrocannabivarin (THCV) displaced [(3)H]CP55940 from specific binding sites on mouse brain and CHO-hCB(2) cell membranes (K(i)=75.4 and 62.8 nM, respectively).THCV (1 microM) also antagonized CP55940-induced stimulation of [(35)S]GTPgammaS binding to these membranes (apparent K(B)=93.1 and 10.1 nM, respectively). In the mouse vas deferens, the ability of Delta9-tetrahydrocannabinol (THC) to inhibit electrically evoked contractions was antagonized by THCV, its apparent K(B)-value (96.7 nM) approximating the apparent K(B)-values for its antagonism of CP55940- and R-(+)-WIN55212-induced stimulation of [(35)S]GTPgammaS binding to mouse brain membranes. THCV also antagonized R-(+)-WIN55212, anandamide, methanandamide and CP55940 in the vas deferens, but with lower apparent K(B)-values (1.5, 1.2, 4.6 and 10.3 nM, respectively).THCV (100 nM) did not oppose clonidine, capsaicin or (-)-7-hydroxy-cannabidiol-dimethylheptyl-induced inhibition of electrically evoked contractions of the vas deferens. Contractile responses of the vas deferens to phenylephrine hydrochloride or beta,gamma-methylene-ATP were not reduced by 1microM THCV or R-(+)-WIN55212, suggesting that THCV interacts with R-(+)-WIN55212 at prejunctional sites. At 32 microM, THCV did reduce contractile responses to phenylephrine hydrochloride and beta,gamma-methylene-ATP, and above 3 microM it inhibited electrically evoked contractions of the vas deferens in an SR141716A-independent manner. In conclusion, THCV behaves as a competitive CB(1) and CB(2) receptor antagonist. In the vas deferens, it antagonized several cannabinoids more potently than THC and was also more potent against CP55940 and R-(+)-WIN55212 in this tissue than in brain membranes. The bases of these agonist- and tissue-dependent effects remain to be established.
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Affiliation(s)
- Adèle Thomas
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD
| | - Lesley A Stevenson
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD
| | - Kerrie N Wease
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD
| | - Martin R Price
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD
| | - Gemma Baillie
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD
| | - Ruth A Ross
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD
| | - Roger G Pertwee
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD
- Author for correspondence:
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Drysdale AJ, Ryan D, Pertwee RG, Platt B. Cannabidiol-induced intracellular Ca2+ elevations in hippocampal cells. Neuropharmacology 2005; 50:621-31. [PMID: 16386766 DOI: 10.1016/j.neuropharm.2005.11.008] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2005] [Revised: 11/09/2005] [Accepted: 11/15/2005] [Indexed: 11/17/2022]
Abstract
The phytocannabinoid cannabidiol (CBD) is at the forefront of therapeutic cannabinoid research due to its non-psychotropic properties. Research supports its use in a variety of disorders, yet the cellular mechanisms of its action remain unclear. In this study, the effect of CBD upon Ca2+ homeostasis in hippocampal cells was characterised. CBD (1 microM) elevated intracellular Ca2+ ([Ca2+]i) by approximately +45% of basal Ca2+ levels in both glia (77% responders) and neurones (51% responders). Responses to CBD were reduced in high excitability HEPES buffered solution (HBS), but not affected in low excitability/low Ca2+ HBS. CBD responses were also significantly reduced (by 50%) by the universal Ca2+ channel blocker cadmium (50 microM) and the L-type specific Ca2+ channel blocker nifedipine (20 microM). Interestingly, intracellular store depletion with thapsigargin (2 microM) had the most dramatic effect on CBD responses, leading on average to a full block of the response. Elevated CBD-induced [Ca2+]i responses (>+100%) were observed in the presence of the CB1 receptor antagonist, AM281 (1 microM), and the vanilloid receptor antagonist, capsazepine (CPZ, 1 microM). Overall, our data suggest that CBD modulates hippocampal [Ca2+]i homeostasis via intracellular Ca2+ stores and L-type VGCC-mediated Ca2+ entry, with tonic cannabinoid and vanilloid receptor signalling being negatively coupled to this pathway.
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Affiliation(s)
- Alison J Drysdale
- School of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
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Grant I, Cahn BR. Cannabis and endocannabinoid modulators: Therapeutic promises and challenges. ACTA ACUST UNITED AC 2005; 5:185-199. [PMID: 18806886 DOI: 10.1016/j.cnr.2005.08.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The discovery that botanical cannabinoids such as delta-9 tetrahydrocannabinol exert some of their effect through binding specific cannabinoid receptor sites has led to the discovery of an endocannabinoid signaling system, which in turn has spurred research into the mechanisms of action and addiction potential of cannabis on the one hand, while opening the possibility of developing novel therapeutic agents on the other. This paper reviews current understanding of CB1, CB2, and other possible cannabinoid receptors, their arachidonic acid derived ligands (e.g. anandamide; 2 arachidonoyl glycerol), and their possible physiological roles. CB1 is heavily represented in the central nervous system, but is found in other tissues as well; CB2 tends to be localized to immune cells. Activation of the endocannabinoid system can result in enhanced or dampened activity in various neural circuits depending on their own state of activation. This suggests that one function of the endocannabinoid system may be to maintain steady state. The therapeutic action of botanical cannabis or of synthetic molecules that are agonists, antagonists, or which may otherwise modify endocannabinoid metabolism and activity indicates they may have promise as neuroprotectants, and may be of value in the treatment of certain types of pain, epilepsy, spasticity, eating disorders, inflammation, and possibly blood pressure control.
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Affiliation(s)
- Igor Grant
- Department of Psychiatry, University of California San Diego, Center for Medicinal Cannabis Research, 9500 Gilman Drive, La Jolla, CA 92093-0680, USA
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