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Singh S, Sarroza D, English A, McGrory M, Dong A, Zweifel L, Land BB, Li Y, Bruchas MR, Stella N. Pharmacological Characterization of the Endocannabinoid Sensor GRAB eCB2.0. Cannabis Cannabinoid Res 2023. [PMID: 38064488 DOI: 10.1089/can.2023.0036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023] Open
Abstract
Introduction: The endocannabinoids (eCBs), 2-arachidonoylglycerol (2-AG) and arachidonoyl ethanolamine (AEA), are produced by separate enzymatic pathways, activate cannabinoid (CB) receptors with distinct pharmacological profiles, and differentially regulate pathophysiological processes. The genetically encoded sensor, GRABeCB2.0, detects real-time changes in eCB levels in cells in culture and preclinical model systems; however, its activation by eCB analogues produced by cells and by phyto-CBs remains uncharacterized, a current limitation when interpreting changes in its response. This information could provide additional utility for the tool in in vivo pharmacology studies of phyto-CB action. Materials and Methods: GRABeCB2.0 was expressed in cultured HEK293 cells. Live cell confocal microscopy and high-throughput fluorescent signal measurements. Results: 2-AG increased GRABeCB2.0 fluorescent signal (EC50=85 nM), and the cannabinoid 1 receptor (CB1R) antagonist, SR141716 (SR1), decreased GRABeCB2.0 signal (IC50=3.3 nM), responses that mirror their known potencies at the CB1R. GRABeCB2.0 fluorescent signal also increased in response to AEA (EC50=815 nM), the eCB analogues 2-linoleoylglycerol and 2-oleoylglycerol (EC50=632 and 868 nM, respectively), Δ9-tetrahydrocannabinol (Δ9-THC), and Δ8-THC (EC50=1.6 and 2.0 μM, respectively), and the artificial CB1R agonist, CP55,940 (CP; EC50=82 nM); however their potencies were less than what has been described at CB1R. Cannabidiol (CBD) did not affect basal GRABeCB2.0 fluorescent signal and yet reduced the 2-AG stimulated GRABeCB2.0 responses (IC50=9.7 nM). Conclusions: 2-AG and SR1 modulate the GRABeCB2.0 fluorescent signal with EC50 values that mirror their potencies at CB1R, whereas AEA, eCB analogues, THC, and CP increase GRABeCB2.0 fluorescent signal with EC50 values significantly lower than their potencies at CB1R. CBD reduces the 2-AG response without affecting basal signal, suggesting that GRABeCB2.0 retains the negative allosteric modulator (NAM) property of CBD at CB1R. This study describes the pharmacological profile of GRABeCB2.0 to improve interpretation of changes in fluorescent signal in response to a series of known eCBs and CB1R ligands.
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Affiliation(s)
- Simar Singh
- Department of Pharmacology, Pain, and Emotion, School of Medicine, University of Washington, Seattle, Washington, USA
- Center for Cannabis Research, Pain, and Emotion, School of Medicine, University of Washington, Seattle, Washington, USA
- Center for the Neurobiology of Addiction, Pain, and Emotion, School of Medicine, University of Washington, Seattle, Washington, USA
| | - Dennis Sarroza
- Department of Pharmacology, Pain, and Emotion, School of Medicine, University of Washington, Seattle, Washington, USA
| | - Anthony English
- Department of Pharmacology, Pain, and Emotion, School of Medicine, University of Washington, Seattle, Washington, USA
- Center for Cannabis Research, Pain, and Emotion, School of Medicine, University of Washington, Seattle, Washington, USA
- Center for the Neurobiology of Addiction, Pain, and Emotion, School of Medicine, University of Washington, Seattle, Washington, USA
| | - Maya McGrory
- Department of Pharmacology, Pain, and Emotion, School of Medicine, University of Washington, Seattle, Washington, USA
| | - Ao Dong
- Peking University School of Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Larry Zweifel
- Department of Pharmacology, Pain, and Emotion, School of Medicine, University of Washington, Seattle, Washington, USA
- Center for Cannabis Research, Pain, and Emotion, School of Medicine, University of Washington, Seattle, Washington, USA
- Center for the Neurobiology of Addiction, Pain, and Emotion, School of Medicine, University of Washington, Seattle, Washington, USA
- Department of Psychiatry and Behavioral Sciences, School of Medicine, University of Washington, Seattle, Washington, USA
| | - Benjamin B Land
- Department of Pharmacology, Pain, and Emotion, School of Medicine, University of Washington, Seattle, Washington, USA
- Center for Cannabis Research, Pain, and Emotion, School of Medicine, University of Washington, Seattle, Washington, USA
- Center for the Neurobiology of Addiction, Pain, and Emotion, School of Medicine, University of Washington, Seattle, Washington, USA
| | - Yulong Li
- Peking University School of Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Michael R Bruchas
- Department of Pharmacology, Pain, and Emotion, School of Medicine, University of Washington, Seattle, Washington, USA
- Center for Cannabis Research, Pain, and Emotion, School of Medicine, University of Washington, Seattle, Washington, USA
- Center for the Neurobiology of Addiction, Pain, and Emotion, School of Medicine, University of Washington, Seattle, Washington, USA
- Department of Anesthesiology, School of Medicine, University of Washington, Seattle, Washington, USA
| | - Nephi Stella
- Department of Pharmacology, Pain, and Emotion, School of Medicine, University of Washington, Seattle, Washington, USA
- Center for Cannabis Research, Pain, and Emotion, School of Medicine, University of Washington, Seattle, Washington, USA
- Center for the Neurobiology of Addiction, Pain, and Emotion, School of Medicine, University of Washington, Seattle, Washington, USA
- Department of Psychiatry and Behavioral Sciences, School of Medicine, University of Washington, Seattle, Washington, USA
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Hill MN, Haney M, Hillard CJ, Karhson DS, Vecchiarelli HA. The endocannabinoid system as a putative target for the development of novel drugs for the treatment of psychiatric illnesses. Psychol Med 2023; 53:7006-7024. [PMID: 37671673 PMCID: PMC10719691 DOI: 10.1017/s0033291723002465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 07/25/2023] [Accepted: 07/28/2023] [Indexed: 09/07/2023]
Abstract
Cannabis is well established to impact affective states, emotion and perceptual processing, primarily through its interactions with the endocannabinoid system. While cannabis use is quite prevalent in many individuals afflicted with psychiatric illnesses, there is considerable controversy as to whether cannabis may worsen these conditions or provide some form of therapeutic benefit. The development of pharmacological agents which interact with components of the endocannabinoid system in more localized and discrete ways then via phytocannabinoids found in cannabis, has allowed the investigation if direct targeting of the endocannabinoid system itself may represent a novel approach to treat psychiatric illness without the potential untoward side effects associated with cannabis. Herein we review the current body of literature regarding the various pharmacological tools that have been developed to target the endocannabinoid system, their impact in preclinical models of psychiatric illness and the recent data emerging of their utilization in clinical trials for psychiatric illnesses, with a specific focus on substance use disorders, trauma-related disorders, and autism. We highlight several candidate drugs which target endocannabinoid function, particularly inhibitors of endocannabinoid metabolism or modulators of cannabinoid receptor signaling, which have emerged as potential candidates for the treatment of psychiatric conditions, particularly substance use disorder, anxiety and trauma-related disorders and autism spectrum disorders. Although there needs to be ongoing clinical work to establish the potential utility of endocannabinoid-based drugs for the treatment of psychiatric illnesses, the current data available is quite promising and shows indications of several potential candidate diseases which may benefit from this approach.
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Affiliation(s)
- Matthew N. Hill
- Departments of Cell Biology and Anatomy & Psychiatry, Cumming School of Medicine, Hotchkiss Brain Institute and The Mathison Centre for Mental Health Research and Education, University of Calgary, Calgary, Canada
| | - Margaret Haney
- Department of Psychiatry, New York State Psychiatric Institute and Columbia University Irving Medical Center, New York, USA
| | - Cecilia J. Hillard
- Department of Pharmacology and Toxicology, Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, USA
| | - Debra S. Karhson
- Department of Psychology, University of New Orleans, New Orleans, USA
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Singh S, Sarroza D, English A, McGrory M, Dong A, Zweifel L, Land BB, Li Y, Bruchas MR, Stella N. Pharmacological characterization of the endocannabinoid sensor GRAB eCB2.0. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.03.531053. [PMID: 36945533 PMCID: PMC10028790 DOI: 10.1101/2023.03.03.531053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Introduction The endocannabinoids (eCBs), 2-arachidonoylglycerol (2-AG) and arachidonoyl ethanolamine (AEA), are produced by separate enzymatic pathways, activate cannabinoid receptors with distinct pharmacology, and differentially regulate pathophysiological processes. The genetically encoded sensor, GRABeCB2.0, detects real-time changes in eCB levels in cells in culture and preclinical model systems; however, its activation by eCB analogues produced by cells and by phyto-cannabinoids remains uncharacterized, a current limitation when interpreting changes in its response. This information could provide additional utility for the tool in in vivo pharmacology studies of phyto-cannabinoid action. Methods GRABeCB2.0 was expressed in cultured HEK293 cells. Live cell confocal microscopy and high-throughput fluorescent signal measurements. Results 2-AG increased GRABeCB2.0 fluorescent signal (EC50 = 85 nM), and the cannabinoid 1 receptor (CB1R) antagonist, SR141617, decreased GRABeCB2.0 signal (SR1, IC50 = 3.3 nM), responses that mirror their known potencies at cannabinoid 1 receptors (CB1R). GRABeCB2.0 fluorescent signal also increased in response to AEA (EC50 = 815 nM), the eCB analogues 2-linoleoylglycerol and 2-oleoylglycerol (2-LG and 2-OG, EC50s = 1.5 and 1.0 μM, respectively), Δ9-tetrahydrocannabinol (Δ9-THC) and Δ8-THC (EC50s = 1.6 and 2.0 μM, respectively), and the artificial CB1R agonist, CP55,940 (CP, EC50 = 82 nM); however their potencies were less than what has been described at CB1R. Cannabidiol (CBD) did not affect basal GRABeCB2.0 fluorescent signal and yet reduced the 2-AG stimulated GRABeCB2.0 responses (IC50 = 8.8 nM). Conclusions 2-AG and SR1 modulate the GRABeCB2.0 fluorescent signal with EC50s that mirror their potencies at CB1R whereas AEA, eCB analogues, THC and CP increase GRABeCB2.0 fluorescent signal with EC50s significantly lower than their potencies at CB1R. CBD reduces the 2-AG response without affecting basal signal, suggesting that GRABeCB2.0 retains the negative allosteric modulator (NAM) property of CBD at CB1R. This study describes the pharmacological profile of GRABeCB2.0 to improve interpretation of changes in fluorescent signal in response to a series of known eCBs and CB1R ligands.
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Affiliation(s)
- Simar Singh
- Department of Pharmacology, University of Washington, Seattle, USA
- Center for Cannabis Research, University of Washington, Seattle, USA
- Center for the Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, USA
| | - Dennis Sarroza
- Department of Pharmacology, University of Washington, Seattle, USA
| | - Anthony English
- Department of Pharmacology, University of Washington, Seattle, USA
- Center for Cannabis Research, University of Washington, Seattle, USA
- Center for the Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, USA
| | - Maya McGrory
- Department of Pharmacology, University of Washington, Seattle, USA
| | - Ao Dong
- Peking University School of Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Larry Zweifel
- Department of Pharmacology, University of Washington, Seattle, USA
- Center for Cannabis Research, University of Washington, Seattle, USA
- Center for the Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, USA
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, USA
| | - Benjamin B. Land
- Department of Pharmacology, University of Washington, Seattle, USA
- Center for Cannabis Research, University of Washington, Seattle, USA
- Center for the Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, USA
| | - Yulong Li
- Peking University School of Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Michael R. Bruchas
- Department of Pharmacology, University of Washington, Seattle, USA
- Center for Cannabis Research, University of Washington, Seattle, USA
- Center for the Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, USA
- Department of Anesthesiology, School of Medicine, University of Washington, Seattle, USA
| | - Nephi Stella
- Department of Pharmacology, University of Washington, Seattle, USA
- Center for Cannabis Research, University of Washington, Seattle, USA
- Center for the Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, USA
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, USA
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de Araujo KRG, Fabris AL, Neves Júnior LF, de Carvalho Ponce J, Soares AL, Costa JL, Yonamine M. The mystery behind the apprehensions of the selective cannabinoid receptor type-2 agonist BZO-HEXOXIZID (MDA-19) as a drug of abuse. Forensic Toxicol 2023; 41:142-150. [PMID: 36652069 DOI: 10.1007/s11419-022-00646-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 09/02/2022] [Indexed: 01/21/2023]
Abstract
PURPOSE MDA-19 or BZO-HEXOXIZID (N'-[(3Z)-1-(1-hexyl)-2-oxo-1,2-dihydro-3H-indol-3-ylidene]-benzohydrazide), in a more recent nomenclature, was first synthesized in 2008 as a selective type-2 cannabinoid receptor (CB2) agonist due to its potential to treat neuropathic pain. In Brazil, this substance was identified in a series of 53 apprehensions between September 2021 and February 2022. Nevertheless, what intrigues toxicologists is that BZO-HEXOXIZID does not exert significant type-1 cannabinoid receptor (CB1) agonism-which is responsible for the well-known psychoactivity of Δ-9-tetrahydrocannabinol. Thus, the objective of this work is to report the first apprehension and identification of BZO-HEXOXIZID in Brazil and to discuss pharmacologically the possible reasons why a CB2 agonist has been incorporated to the illicit market. METHODS Suspected seized samples were sent to the Laboratory of the Scientific Police of the State of Sao Paulo. After the screening, samples were confirmed for the presence of BZO-HEXOXIZID using chromatography gas-mass spectrometry, Fourier-transform infrared spectroscopy and nuclear magnetic resonance techniques. RESULTS Of the 53 samples analyzed, 25 contained only BZO-HEXOXIZID and 28 with mixtures, of which 11 with the CB1 agonist ADB-BUTINACA. Other substances were found in association such as cocaine and caffeine. CONCLUSIONS BZO-HEXOXIZID was detected in a series of seized materials for the first time in Brazil. Nevertheless, there are still unanswered questions regarding the use of this selective CB2 agonist as a drug of abuse.
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Affiliation(s)
| | - André Luis Fabris
- School of Pharmaceutical Sciences, University of São Paulo, São Paulo, SP, 05508-000, Brazil
| | - Luiz F Neves Júnior
- Superintendence of the Technical-Scientific Police, Institute of Criminalistics, São Paulo, SP, 05507-060, Brazil
| | - Júlio de Carvalho Ponce
- Superintendence of the Technical-Scientific Police, Institute of Criminalistics, São Paulo, SP, 05507-060, Brazil
| | - Alexandre Learth Soares
- Instrumental Analysis Laboratory of the Technical-Scientific Police, Institute of Criminalistics, São Paulo, SP, 05507-060, Brazil
| | - José Luiz Costa
- Campinas Poison Control Center, University of Campinas, Campinas, SP, 13083-859, Brazil
| | - Mauricio Yonamine
- School of Pharmaceutical Sciences, University of São Paulo, São Paulo, SP, 05508-000, Brazil
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Saumell-Esnaola M, Elejaga-Jimeno A, Echeazarra L, Borrega-Román L, Barrondo S, López de Jesús M, González-Burguera I, Gómez-Caballero A, Goicolea MA, Sallés J, García del Caño G. Design and validation of recombinant protein standards for quantitative Western blot analysis of cannabinoid CB1 receptor density in cell membranes: an alternative to radioligand binding methods. Microb Cell Fact 2022; 21:192. [PMID: 36109736 PMCID: PMC9479267 DOI: 10.1186/s12934-022-01914-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 08/27/2022] [Indexed: 11/16/2022] Open
Abstract
Background Replacement of radioligand binding assays with antibody-antigen interaction-based approaches for quantitative analysis of G protein-coupled receptor (GPCR) levels requires the use of purified protein standards containing the antigen. GPCRs in general and cannabinoid CB1 receptor in particular show a progressive tendency to aggregate and precipitate in aqueous solution outside of their biological context due to the low solubility that the hydrophobic nature imprinted by their seven transmembrane domains. This renders full-length recombinant GPCRs useless for analytical purposes, a problem that can be overcome by engineering soluble recombinant fragments of the receptor containing the antigen. Results Here we generated highly soluble and stable recombinant protein constructs GST-CB1414–472 and GST-CB1414-442 containing much of the human CB1 receptor C-terminal tail for use as standard and negative control, respectively, in quantitative Western blot analysis of CB1 receptor expression on crude synaptosomes of the adult rat brain cortex. To this end we used three different antibodies, all raised against a peptide comprising the C-terminal residues 443–473 of the mouse CB1 receptor that corresponds to residues 442–472 in the human homolog. Estimated values of CB1 receptor density obtained by quantitative Western blot were of the same order of magnitude but slightly higher than values obtained by the radioligand saturation binding assay. Conclusions Collectively, here we provide a suitable Western blot-based design as a simple, cost-effective and radioactivity-free alternative for the quantitative analysis of CB1 receptor expression, and potentially of any GPCR, in a variety of biological samples. The discrepancies between the results obtained by quantitative Western blot and radioligand saturation binding techniques are discussed in the context of their particular theoretical bases and methodological constraints. Supplementary Information The online version contains supplementary material available at 10.1186/s12934-022-01914-1.
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Rabino M, Mallia S, Castiglioni E, Rovina D, Pompilio G, Gowran A. The Endocannabinoid System and Cannabidiol: Past, Present, and Prospective for Cardiovascular Diseases. Pharmaceuticals (Basel) 2021; 14:ph14090936. [PMID: 34577636 PMCID: PMC8472406 DOI: 10.3390/ph14090936] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 09/09/2021] [Accepted: 09/13/2021] [Indexed: 12/18/2022] Open
Abstract
In the past, cannabis was commonly associated with mysticism and illegality. Fortunately, in recent years perspectives and discourses have changed. More prominence has been given to the rigorous scientific effort that led to the discovery of cannabis' many physiological actions and endogenous signalling mechanisms. The endocannabinoid system is a complex and heterogeneous pro-homeostatic network comprising different receptors with several endogenous ligands, numerous metabolic enzymes and regulatory proteins. Therefore, it is not surprising that alterations and dysfunctions of the endocannabinoid system are observed in almost every category of disease. Such high degree of pathophysiological involvement suggests the endocannabinoid system is a promising therapeutic target and prompted the translation of resurgent scientific findings into clinical therapies. Shifting attitudes toward cannabis also raised other matters such as increased patient awareness, prescription requests, self-medication, recreational use, recognition of new knowledge gaps, renewed scientific activity, and seemingly exponential growth of the cannabis industry. This review, following a general overview of cannabis and the endocannabinoid system, assiduously describes its role within the context of cardiovascular diseases, paying particular attention to the Janus influence that endocannabinoid system modulators can have on the cardiovascular system.
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Affiliation(s)
- Martina Rabino
- Unit of Vascular Biology and Regenerative Medicine, Centro Cardiologico Monzino-IRCCS, 20138 Milan, Italy
| | - Sara Mallia
- Unit of Vascular Biology and Regenerative Medicine, Centro Cardiologico Monzino-IRCCS, 20138 Milan, Italy
| | - Elisa Castiglioni
- Unit of Vascular Biology and Regenerative Medicine, Centro Cardiologico Monzino-IRCCS, 20138 Milan, Italy
| | - Davide Rovina
- Unit of Vascular Biology and Regenerative Medicine, Centro Cardiologico Monzino-IRCCS, 20138 Milan, Italy
| | - Giulio Pompilio
- Unit of Vascular Biology and Regenerative Medicine, Centro Cardiologico Monzino-IRCCS, 20138 Milan, Italy
- Department of Cardiac Surgery, Centro Cardiologico Monzino-IRCCS, 20138 Milan, Italy
- Department of Biomedical, Surgical and Dental Sciences, University of Milan, 20138 Milan, Italy
| | - Aoife Gowran
- Unit of Vascular Biology and Regenerative Medicine, Centro Cardiologico Monzino-IRCCS, 20138 Milan, Italy
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Kuzma-Hunt AG, Truong VB, Favetta LA. Glucocorticoids, Stress and Delta-9 Tetrahydrocannabinol (THC) during Early Embryonic Development. Int J Mol Sci 2021; 22:7289. [PMID: 34298908 PMCID: PMC8307766 DOI: 10.3390/ijms22147289] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 06/24/2021] [Accepted: 06/29/2021] [Indexed: 12/13/2022] Open
Abstract
Elevated molecular stress in women is known to have negative impacts on the reproductive development of oocytes and the embryos prior to implantation. In recent years, the prevalence of cannabis use among women of reproductive age has risen due to its ability to relieve psychological stress and nausea, which are mediated by its psychoactive component, ∆-9-tetrahydrocannabinol (THC). Although cannabis is the most popular recreational drug of the 21st century, much is unknown about its influence on molecular stress in reproductive tissues. The current literature has demonstrated that THC causes dose- and time-dependent alterations in glucocorticoid signaling, which have the potential to compromise morphology, development, and quality of oocytes and embryos. However, there are inconsistencies across studies regarding the mechanisms for THC-dependent changes in stress hormones and how either compounds may drive or arrest development. Factors such as variability between animal models, physiologically relevant doses, and undiscovered downstream gene targets of both glucocorticoids and THC could account for such inconsistencies. This review evaluates the results of studies which have investigated the effects of glucocorticoids on reproductive development and how THC may alter stress signaling in relevant tissues.
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Affiliation(s)
| | | | - Laura A. Favetta
- Reproductive Health and Biotechnology Laboratory, Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada; (A.G.K.-H.); (V.B.T.)
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Haspula D, Clark MA. Cannabinoid Receptors: An Update on Cell Signaling, Pathophysiological Roles and Therapeutic Opportunities in Neurological, Cardiovascular, and Inflammatory Diseases. Int J Mol Sci 2020; 21:E7693. [PMID: 33080916 PMCID: PMC7590033 DOI: 10.3390/ijms21207693] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 10/14/2020] [Accepted: 10/15/2020] [Indexed: 12/16/2022] Open
Abstract
The identification of the human cannabinoid receptors and their roles in health and disease, has been one of the most significant biochemical and pharmacological advancements to have occurred in the past few decades. In spite of the major strides made in furthering endocannabinoid research, therapeutic exploitation of the endocannabinoid system has often been a challenging task. An impaired endocannabinoid tone often manifests as changes in expression and/or functions of type 1 and/or type 2 cannabinoid receptors. It becomes important to understand how alterations in cannabinoid receptor cellular signaling can lead to disruptions in major physiological and biological functions, as they are often associated with the pathogenesis of several neurological, cardiovascular, metabolic, and inflammatory diseases. This review focusses mostly on the pathophysiological roles of type 1 and type 2 cannabinoid receptors, and it attempts to integrate both cellular and physiological functions of the cannabinoid receptors. Apart from an updated review of pre-clinical and clinical studies, the adequacy/inadequacy of cannabinoid-based therapeutics in various pathological conditions is also highlighted. Finally, alternative strategies to modulate endocannabinoid tone, and future directions are also emphasized.
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Affiliation(s)
- Dhanush Haspula
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA;
| | - Michelle A. Clark
- Department of Pharmaceutical Sciences, College of Pharmacy, Nova Southeastern University, Fort Lauderdale, FL 33314, USA
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Nguyen T, Gamage TF, Decker AM, German N, Langston TL, Farquhar CE, Kenakin TP, Wiley JL, Thomas BF, Zhang Y. Diarylureas Containing 5-Membered Heterocycles as CB 1 Receptor Allosteric Modulators: Design, Synthesis, and Pharmacological Evaluation. ACS Chem Neurosci 2019; 10:518-527. [PMID: 30188693 DOI: 10.1021/acschemneuro.8b00396] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Allosteric modulators have attracted significant interest as an alternate strategy to modulate CB1 receptor signaling for therapeutic benefits that may avoid the adverse effects associated with orthosteric ligands. Here we extended our previous structure-activity relationship studies on the diarylurea-based CB1 negative allosteric modulators (NAMs) by introducing five-membered heterocycles to replace the 5-pyrrolidinylpyridinyl group in PSNCBAM-1 (1), one of the first generation CB1 allosteric modulators. Many of these compounds had comparable potency to 1 in blocking the CB1 agonist CP55,940 stimulated calcium mobilization and [35S]GTP-γ-S binding. Similar to 1, most compounds showed positive cooperativity by increasing [3H]CP55,940 binding, consistent with the positive allosteric modulator (PAM)-antagonist mechanism. Interestingly, these compounds exhibited differences in ability to increase specific binding of [3H]CP55,940 and decrease binding of the antagonist [3H]SR141716. In saturation binding studies, only increases in [3H]CP55,940 Bmax, but not Kd, were observed, suggesting that these compounds stabilize low affinity receptors into a high affinity state. Among the series, the 2-pyrrolyl analogue (13) exhibited greater potency than 1 in the [35S]GTP-γ-S binding assay and significantly enhanced the maximum binding level in the [3H]CP5,5940 binding assay, indicating greater CB1 receptor affinity and/or cooperativity.
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Affiliation(s)
- Thuy Nguyen
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Thomas F. Gamage
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Ann M. Decker
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Nadezhda German
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Tiffany L. Langston
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Charlotte E. Farquhar
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Terry P. Kenakin
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Jenny L. Wiley
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Brian F. Thomas
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Yanan Zhang
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
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Potential Mechanisms Underlying the Deleterious Effects of Synthetic Cannabinoids Found in Spice/K2 Products. Brain Sci 2019; 9:brainsci9010014. [PMID: 30654473 PMCID: PMC6357179 DOI: 10.3390/brainsci9010014] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 01/11/2019] [Accepted: 01/13/2019] [Indexed: 12/17/2022] Open
Abstract
The chief psychoactive constituent of many bioactive phytocannabinoids (Δ9-tetrahydrocannabinol, Δ9-THC) found in hemp, cannabis or marijuana plants are scientifically denoted by the Latin term, Cannabis sativa, acts on cell surface receptors. These receptors are ubiquitously expressed. To date, two cannabinoid receptors have been cloned and characterized. Cannabinoid receptor type 1 (CB1R) is found to serve as the archetype for cannabinoid action in the brain. They have attracted wide interest as the mediator of all psychoactive properties of exogenous and endogenous cannabinoids and they are abundantly expressed on most inhibitory and excitatory neurons. Recent evidence established that cannabinoid receptor type 2 (CB2R) is also expressed in the neurons at both presynaptic and postsynaptic terminals and are involved in neuropsychiatric effects. Distinct types of cells in many regions in the brain express CB2Rs and the cellular origin of CB2Rs that induce specific behavioral effects are emerging. To mimic the bliss effects of marijuana, synthetic cannabinoids (SCBs) have been sprayed onto plant material, and this plant material has been consequently packaged and sold under brand name “Spice” or “K2”. These SCBs have been shown to maintain their affinity and functional activity for CB1R and CB2R and have been shown to cause severe harmful effects when compared to the effects of Δ9-THC. The present review discusses the potential brain mechanisms that are involved in the deleterious effects of SCBs.
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Endocannabinoid System and Alcohol Abuse Disorders. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1162:89-127. [PMID: 31332736 DOI: 10.1007/978-3-030-21737-2_6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Δ9-tetrahydrocannabinol (Δ9-THC), the primary active component in Cannabis sativa preparations such as hashish and marijuana, signals by binding to cell surface receptors. Two types of receptors have been cloned and characterized as cannabinoid (CB) receptors. CB1 receptors (CB1R) are ubiquitously present in the central nervous system (CNS) and are present in both inhibitory interneurons and excitatory neurons at the presynaptic terminal. CB2 receptors (CB2R) are demonstrated in microglial cells, astrocytes, and several neuron subpopulations and are present in both pre- and postsynaptic terminals. The majority of studies on these receptors have been conducted in the past two and half decades after the identification of the molecular constituents of the endocannabinoid (eCB) system that started with the characterization of CB1R. Subsequently, the seminal discovery was made, which suggested that alcohol (ethanol) alters the eCB system, thus establishing the contribution of the eCB system in the motivation to consume ethanol. Several preclinical studies have provided evidence that CB1R significantly contributes to the motivational and reinforcing properties of ethanol and that the chronic consumption of ethanol alters eCB transmitters and CB1R expression in the brain nuclei associated with addiction pathways. Additionally, recent seminal studies have further established the role of the eCB system in the development of ethanol-induced developmental disorders, such as fetal alcohol spectrum disorders (FASD). These results are augmented by in vitro and ex vivo studies, showing that acute and chronic treatment with ethanol produces physiologically relevant alterations in the function of the eCB system during development and in the adult stage. This chapter provides a current and comprehensive review of the literature concerning the role of the eCB system in alcohol abuse disorders (AUD).
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12
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Gorzkiewicz A, Szemraj J. Brain endocannabinoid signaling exhibits remarkable complexity. Brain Res Bull 2018; 142:33-46. [PMID: 29953913 DOI: 10.1016/j.brainresbull.2018.06.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 06/06/2018] [Accepted: 06/21/2018] [Indexed: 01/04/2023]
Abstract
The endocannabinoid (eCB) signaling system is one of the most extensive of the mammalian brain. Despite the involvement of only few specific ligands and receptors, the system encompasses a vast diversity of triggered mechanisms and driven effects. It mediates a wide range of phenomena, including the regulation of transmitter release, neural excitability, synaptic plasticity, impulse spread, long-term neuronal potentiation, neurogenesis, cell death, lineage segregation, cell migration, inflammation, oxidative stress, nociception and the sleep cycle. It is also known to be involved in the processes of learning and memory formation. This extensive scope of action is attained by combining numerous variables. In a properly functioning brain, the correlations of these variables are kept in a strictly controlled balance; however, this balance is disrupted in many pathological conditions. However, while this balance is known to be disrupted by drugs in the case of addicts, the stimuli and mechanisms influencing the neurodegenerating brain remain elusive. This review examines the multiple factors and phenomena affecting the eCB signaling system in the brain. It evaluates techniques of controlling the eCB system to identify the obstacles in their applications and highlights the crucial interdependent variables that may influence biomedical research outcomes.
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Affiliation(s)
- Anna Gorzkiewicz
- Medical University of Lodz, ul.Mazowiecka 6/8, 92-215, Lodz, Poland.
| | - Janusz Szemraj
- Medical University of Lodz, ul.Mazowiecka 6/8, 92-215, Lodz, Poland
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13
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Costain WJ, Rasquinha I, Comas T, Hewitt M, Aylsworth A, Rouleau Y, Marleau V, Soo EC, Tauskela JS. Analysis of the pharmacological properties of JWH-122 isomers and THJ-2201, RCS-4 and AB-CHMINACA in HEK293T cells and hippocampal neurons. Eur J Pharmacol 2018; 823:96-104. [PMID: 29408093 DOI: 10.1016/j.ejphar.2018.01.043] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 01/04/2018] [Accepted: 01/25/2018] [Indexed: 11/15/2022]
Abstract
Synthetic cannabinoids are marketed as legal alternatives to Δ9-THC, and are a growing worldwide concern as these drugs are associated with severe adverse effects. Unfortunately, insufficient information regarding the physiological and pharmacological effects of emerging synthetic cannabinoids (ESCs) makes their regulation by government authorities difficult. One strategy used to evade regulation is to distribute isomers of regulated synthetic cannabinoids. This study characterized the pharmacological properties of a panel of ESCs in comparison to Δ9-THC, as well as six JWH-122 isomers relative to its parent compound (JWH-122-4). Two cell-based assays were used to determine the potency and efficacy of ESCs and a panel of reference cannabinoids. HEK293T cells were transfected with human cannabinoid receptor 1 (CB1) and pGloSensor-22F, and the inhibition of forskolin-stimulated cyclic adenosine monophosphate (cAMP) levels was monitored in live cells. All ESCs examined were classified as agonists, with the following rank order of potency: Win 55,212-2 > CP 55,940 > JWH-122-4 > Δ9-THC ≈ RCS-4 ≈ THJ-2201 > JWH-122-5 > JWH-122-7 > JWH-122-2 ≈ AB-CHMINACA > JWH-122-8 > JWH-122-6 > JWH-122-3. Evaluation of ESC-stimulated Ca2+ transients in cultured rat primary hippocampal neurons confirmed the efficacy of four of the most potent ESCs (JWH-122-4, JWH-122-5, JWH-122-7 and AB-CHMINACA). This work helps regulatory agencies make informed decisions concerning these poorly characterized recreational drugs.
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Affiliation(s)
- Willard J Costain
- Department of Translational Bioscience, Human Health Therapeutics, National Research Council, 1200 Montreal Road, Ottawa, Ontario, Canada K1A 0R6.
| | - Ingrid Rasquinha
- Department of Translational Bioscience, Human Health Therapeutics, National Research Council, 1200 Montreal Road, Ottawa, Ontario, Canada K1A 0R6
| | - Tanya Comas
- Department of Translational Bioscience, Human Health Therapeutics, National Research Council, 1200 Montreal Road, Ottawa, Ontario, Canada K1A 0R6
| | - Melissa Hewitt
- Department of Translational Bioscience, Human Health Therapeutics, National Research Council, 1200 Montreal Road, Ottawa, Ontario, Canada K1A 0R6
| | - Amy Aylsworth
- Department of Translational Bioscience, Human Health Therapeutics, National Research Council, 1200 Montreal Road, Ottawa, Ontario, Canada K1A 0R6
| | - Yanouchka Rouleau
- Department of Translational Bioscience, Human Health Therapeutics, National Research Council, 1200 Montreal Road, Ottawa, Ontario, Canada K1A 0R6
| | - Vincent Marleau
- Analytical and Forensic Services Division, Contraband Drug Analysis, Canada Border Services Agency, 79 Bentley Avenue, 2nd Floor, Ottawa, Ontario, Canada K1A 0L8
| | - Evelyn C Soo
- Health Products and Food Branch, Biologics and Genetic Therapies Directorate, Health Canada, 150 Tunney's Pasture Driveway #1605-676, Ottawa, Ontario, Canada K1A 0K9
| | - Joseph S Tauskela
- Department of Translational Bioscience, Human Health Therapeutics, National Research Council, 1200 Montreal Road, Ottawa, Ontario, Canada K1A 0R6
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Cooper A, Singh S, Hook S, Tyndall JDA, Vernall AJ. Chemical Tools for Studying Lipid-Binding Class A G Protein-Coupled Receptors. Pharmacol Rev 2017; 69:316-353. [PMID: 28655732 DOI: 10.1124/pr.116.013243] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 05/15/2017] [Indexed: 12/16/2022] Open
Abstract
Cannabinoid, free fatty acid, lysophosphatidic acid, sphingosine 1-phosphate, prostanoid, leukotriene, bile acid, and platelet-activating factor receptor families are class A G protein-coupled receptors with endogenous lipid ligands. Pharmacological tools are crucial for studying these receptors and addressing the many unanswered questions surrounding expression of these receptors in normal and diseased tissues. An inherent challenge for developing tools for these lipid receptors is balancing the often lipophilic requirements of the receptor-binding pharmacophore with favorable physicochemical properties to optimize highly specific binding. In this study, we review the radioligands, fluorescent ligands, covalent ligands, and antibodies that have been used to study these lipid-binding receptors. For each tool type, the characteristics and design rationale along with in vitro and in vivo applications are detailed.
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Affiliation(s)
- Anna Cooper
- School of Pharmacy, University of Otago, Dunedin, New Zealand
| | - Sameek Singh
- School of Pharmacy, University of Otago, Dunedin, New Zealand
| | - Sarah Hook
- School of Pharmacy, University of Otago, Dunedin, New Zealand
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15
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Relating Observed Psychoactive Effects to the Plasma Concentrations of Delta-9-Tetrahydrocannabinol and Its Active Metabolite: An Effect-Compartment Modeling Approach. J Pharm Sci 2017; 107:745-755. [PMID: 28942005 DOI: 10.1016/j.xphs.2017.09.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 08/30/2017] [Accepted: 09/12/2017] [Indexed: 11/22/2022]
Abstract
The medical use of marijuana is increasing, yet little is known about the exposure-response relationship for its psychoactive effects. It is well known that the plasma concentrations of the principal psychoactive component of marijuana, Δ9-tetrahydrocannabinol (THC), do not directly correlate to the observed psychoactive effects. The purpose of this research was to use an effect-compartment modeling approach to predict and relate the concentrations of the psychoactive components (THC and its active metabolite) in the "hypothetical" effect-site compartment to the observed psychoactive effects. A "hypothetical" effect-compartment model was developed using literature data to characterize the observed delay in peak "highness" ratings compared with plasma concentrations of the psychoactive agents following intravenous administration of THC. A direct relationship was established between the reported psychoactive effects ("highness" or intoxication) and the predicted effect-site concentrations of THC. The differences between estimated equilibration half-lives for THC and THC-OH in the effect-compartment model indicated the differential equilibration of parent drug and the active metabolite between plasma and the effect-site. These models contribute to the understanding of the pharmacokinetic-pharmacodynamic relationships associated with marijuana use and are important steps in the prediction of pharmacodynamic effects related to the psychoactive components in marijuana.
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16
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Walter C, Oertel BG, Felden L, Nöth U, Vermehren J, Deichmann R, Lötsch J. Effects of oral Δ 9-tetrahydrocannabinol on the cerebral processing of olfactory input in healthy non-addicted subjects. Eur J Clin Pharmacol 2017; 73:1579-1587. [PMID: 28866743 DOI: 10.1007/s00228-017-2331-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 08/28/2017] [Indexed: 12/15/2022]
Abstract
BACKGROUND Considering the increasing acknowledgment of the human sense of smell as a significant component of the quality of life, olfactory drug effects gain potential clinical importance. A recent observation in a human experimental context indicated that Δ9-tetrahydrocannabinol (THC) impaired the subject's performance in olfactory tests. To further analyze the role of THC in human olfaction, the present report addresses its effects on the central processing of olfactory stimuli. METHODS Employing a placebo-controlled randomized crossover design, an oral dose of 20 mg THC was administered in 15 healthy volunteers. The central processing of olfactory input, consisting of short pulses of gaseous vanillin or hydrogen sulfide, and for comparison, of non-odorous but painful carbon dioxide, were investigated before and after administration of THC or placebo in a pharmacological functional magnet resonance imaging study. RESULTS Following THC administration, the vanillin stimuli lost their pleasantness and became hedonically inert. This observation had its functional correlate in reduced stimulus-associated brain activations located in the left amygdala, the hippocampus and superior temporal pole (peak MNI coordinates x = - 27, y = - 1, z = - 26 mm p = 0.039). Differences in amygdala activations were significantly correlated with the corresponding differences in vanillin pleasantness (p = 0.025). By contrast, no effects were observed on the perception of processing of H2S stimuli. CONCLUSIONS The results support that THC induced a modulation of the central processing of olfactory input. The THC-induced reduction in the pleasantness of a pleasurable odor was accompanied by reduced activations in the limbic system. Results agree with previous observation of negative effects of cannabinoids on the human sense of smell and strengthen the evidence that THC-based medications will be among drugs with olfactory side effects.
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Affiliation(s)
- Carmen Walter
- Fraunhofer Institute of Molecular Biology and Applied Ecology - Project Group Translational Medicine and Pharmacology (IME-TMP), Theodor - Stern - Kai 7, 60590, Frankfurt am Main, Germany
| | - Bruno G Oertel
- Institute of Clinical Pharmacology, Goethe - University, Theodor Stern Kai 7, 60590, Frankfurt am Main, Germany
| | - Lisa Felden
- Institute of Clinical Pharmacology, Goethe - University, Theodor Stern Kai 7, 60590, Frankfurt am Main, Germany
| | - Ulrike Nöth
- Brain Imaging Center, Goethe - University, Schleusenweg 2 - 16, 60528, Frankfurt am Main, Germany
| | - Johannes Vermehren
- Institute of Clinical Pharmacology, Goethe - University, Theodor Stern Kai 7, 60590, Frankfurt am Main, Germany
| | - Ralf Deichmann
- Brain Imaging Center, Goethe - University, Schleusenweg 2 - 16, 60528, Frankfurt am Main, Germany
| | - Jörn Lötsch
- Fraunhofer Institute of Molecular Biology and Applied Ecology - Project Group Translational Medicine and Pharmacology (IME-TMP), Theodor - Stern - Kai 7, 60590, Frankfurt am Main, Germany. .,Institute of Clinical Pharmacology, Goethe - University, Theodor Stern Kai 7, 60590, Frankfurt am Main, Germany.
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17
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Abstract
The CB1 and CB2 cannabinoid receptors (CB1R, CB2R) are members of the G protein-coupled receptor (GPCR) family that were identified over 20 years ago. CB1Rs and CB2Rs mediate the effects of Δ9-tetrahydrocannabinol (Δ9-THC), the principal psychoactive constituent of marijuana, and subsequently identified endogenous cannabinoids (endocannabinoids) anandamide and 2-arachidonoyl glycerol. CB1Rs and CB2Rs have both similarities and differences in their pharmacology. Both receptors recognize multiple classes of agonist and antagonist compounds and produce an array of distinct downstream effects. Natural polymorphisms and alternative splice variants may also contribute to their pharmacological diversity. As our knowledge of the distinct differences grows, we may be able to target select receptor conformations and their corresponding pharmacological responses. This chapter will discuss their pharmacological characterization, distribution, phylogeny, and signaling pathways. In addition, the effects of extended agonist exposure and how that affects signaling and expression patterns of the receptors are considered.
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MESH Headings
- Alternative Splicing/genetics
- Animals
- Humans
- Phylogeny
- Polymorphism, Genetic
- Receptor, Cannabinoid, CB1/agonists
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB2/agonists
- Receptor, Cannabinoid, CB2/genetics
- Receptor, Cannabinoid, CB2/metabolism
- Signal Transduction/drug effects
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Affiliation(s)
- Allyn C Howlett
- Center for Research on Substance Use and Addiction, Wake Forest University Health Sciences, Winston-Salem, NC, United States
| | - Mary E Abood
- Center for Substance Abuse Research, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States.
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18
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Hillard CJ, Beatka M, Sarvaideo J. Endocannabinoid Signaling and the Hypothalamic-Pituitary-Adrenal Axis. Compr Physiol 2016; 7:1-15. [PMID: 28134998 DOI: 10.1002/cphy.c160005] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The elucidation of Δ9-tetrahydrocannabinol as the active principal of Cannabis sativa in 1963 initiated a fruitful half-century of scientific discovery, culminating in the identification of the endocannabinoid signaling system, a previously unknown neuromodulatory system. A primary function of the endocannabinoid signaling system is to maintain or recover homeostasis following psychological and physiological threats. We provide a brief introduction to the endocannabinoid signaling system and its role in synaptic plasticity. The majority of the article is devoted to a summary of current knowledge regarding the role of endocannabinoid signaling as both a regulator of endocrine responses to stress and as an effector of glucocorticoid and corticotrophin-releasing hormone signaling in the brain. We summarize data demonstrating that cannabinoid receptor 1 (CB1R) signaling can both inhibit and potentiate the activation of the hypothalamic-pituitary-adrenal axis by stress. We present a hypothesis that the inhibitory arm has high endocannabinoid tone and also serves to enhance recovery to baseline following stress, while the potentiating arm is not tonically active but can be activated by exogenous agonists. We discuss recent findings that corticotropin-releasing hormone in the amygdala enables hypothalamic-pituitary-adrenal axis activation via an increase in the catabolism of the endocannabinoid N-arachidonylethanolamine. We review data supporting the hypotheses that CB1R activation is required for many glucocorticoid effects, particularly feedback inhibition of hypothalamic-pituitary-adrenal axis activation, and that glucocorticoids mobilize the endocannabinoid 2-arachidonoylglycerol. These features of endocannabinoid signaling make it a tantalizing therapeutic target for treatment of stress-related disorders but to date, this promise is largely unrealized. © 2017 American Physiological Society. Compr Physiol 7:1-15, 2017.
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Affiliation(s)
- Cecilia J Hillard
- Department of Pharmacology and Toxicology, and Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Margaret Beatka
- Department of Pharmacology and Toxicology, and Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Jenna Sarvaideo
- Department of Medicine, and Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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19
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Costain WJ, Tauskela JS, Rasquinha I, Comas T, Hewitt M, Marleau V, Soo EC. Pharmacological characterization of emerging synthetic cannabinoids in HEK293T cells and hippocampal neurons. Eur J Pharmacol 2016; 786:234-245. [DOI: 10.1016/j.ejphar.2016.05.040] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 05/27/2016] [Accepted: 05/30/2016] [Indexed: 10/21/2022]
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20
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Silveira MM, Adams WK, Morena M, Hill MN, Winstanley CA. Δ9-Tetrahydrocannabinol decreases willingness to exert cognitive effort in male rats. J Psychiatry Neurosci 2016; 41:150363. [PMID: 27557094 PMCID: PMC5373702 DOI: 10.1503/jpn.150363] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 03/15/2016] [Accepted: 04/19/2016] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Acceptance of cannabis use is growing. However, prolonged use is associated with diminished psychosocial outcomes, potentially mediated by drug-induced cognitive impairments. Δ9-Tetrahydrocannabinol (THC) is the main psychoactive ingredient in cannabis, yet other phytocannabinoids in the plant, such as cannabidiol (CBD), have unique properties. Given that CBD can modulate the undesirable effects of THC, therapeutic agents, such as nabiximols, contain higher CBD:THC ratios than illicit marijuana. We tested the hypothesis that THC impairs a relevant cognitive function for long-term success, namely willingness to exert cognitive effort for greater rewards, and that CBD could attenuate such decision-making impairments. METHODS Male Long-Evans rats (n = 29) performing the rat cognitive effort task (rCET) received acute THC and CBD, independently and concurrently, in addition to other cannabinoids. Rats chose between 2 options differing in reward magnitude, but also in the cognitive effort (attentional load) required to obtain them. RESULTS We found that THC decreased choice of hard trials without impairing the animals' ability to accurately complete them. Strikingly, this impairment was correlated with CB1 receptor density in the medial prefrontal cortex - an area previously implicated in effortful decision-making. In contrast, CBD did not affect choice. Coadministration of 1:1 CBD:THC matching that in nabiximols modestly attenuated the deleterious effects of THC in "slacker" rats. LIMITATIONS Only male rats were investigated, and the THC/CBD coadministration experiment was carried out in a subset of individuals. CONCLUSION These findings confirm that THC, but not CBD, selectively impairs decision-making involving cognitive effort costs. However, coadministration of CBD only partially ameliorates such THC-induced dysfunction.
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Affiliation(s)
- Mason M. Silveira
- From the Department of Psychology, University of British Columbia, Vancouver, B.C. (Silveira, Adams, Winstanley); the Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, B.C. (Silveira, Adams, Winstanley); and the Hotchkiss Brain Institute, Departments of Cell Biology and Anatomy & Psychiatry, University of Calgary, Calgary, Alta. (Hill)
| | - Wendy K. Adams
- From the Department of Psychology, University of British Columbia, Vancouver, B.C. (Silveira, Adams, Winstanley); the Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, B.C. (Silveira, Adams, Winstanley); and the Hotchkiss Brain Institute, Departments of Cell Biology and Anatomy & Psychiatry, University of Calgary, Calgary, Alta. (Hill)
| | - Maria Morena
- From the Department of Psychology, University of British Columbia, Vancouver, B.C. (Silveira, Adams, Winstanley); the Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, B.C. (Silveira, Adams, Winstanley); and the Hotchkiss Brain Institute, Departments of Cell Biology and Anatomy & Psychiatry, University of Calgary, Calgary, Alta. (Hill)
| | - Matthew N. Hill
- From the Department of Psychology, University of British Columbia, Vancouver, B.C. (Silveira, Adams, Winstanley); the Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, B.C. (Silveira, Adams, Winstanley); and the Hotchkiss Brain Institute, Departments of Cell Biology and Anatomy & Psychiatry, University of Calgary, Calgary, Alta. (Hill)
| | - Catharine A. Winstanley
- From the Department of Psychology, University of British Columbia, Vancouver, B.C. (Silveira, Adams, Winstanley); the Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, B.C. (Silveira, Adams, Winstanley); and the Hotchkiss Brain Institute, Departments of Cell Biology and Anatomy & Psychiatry, University of Calgary, Calgary, Alta. (Hill)
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21
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Pike VW. Considerations in the Development of Reversibly Binding PET Radioligands for Brain Imaging. Curr Med Chem 2016; 23:1818-69. [PMID: 27087244 PMCID: PMC5579844 DOI: 10.2174/0929867323666160418114826] [Citation(s) in RCA: 130] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 04/04/2016] [Accepted: 04/15/2016] [Indexed: 12/17/2022]
Abstract
The development of reversibly binding radioligands for imaging brain proteins in vivo, such as enzymes, neurotransmitter transporters, receptors and ion channels, with positron emission tomography (PET) is keenly sought for biomedical studies of neuropsychiatric disorders and for drug discovery and development, but is recognized as being highly challenging at the medicinal chemistry level. This article aims to compile and discuss the main considerations to be taken into account by chemists embarking on programs of radioligand development for PET imaging of brain protein targets.
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Affiliation(s)
- Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Rm. B3C346A, 10 Center Drive, Bethesda, MD 20892, USA.
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22
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Abstract
Some of the earliest reports of the effects of cannabis consumption on humans were related to endocrine system changes. In this review, the effects of cannabinoids and the role of the CB1 cannabinoid receptor in the regulation of the following endocrine systems are discussed: the hypothalamic-pituitary-gonadal axis, prolactin and oxytocin, thyroid hormone and growth hormone, and the hypothalamic-pituitary-adrenal axis. Preclinical and human study results are presented.
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Affiliation(s)
- Cecilia J Hillard
- Neuroscience Research Center and Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.
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23
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Fanarioti E, Mavrikaki M, Panagis G, Mitsacos A, Nomikos GG, Giompres P. Behavioral and neurochemical changes in mesostriatal dopaminergic regions of the rat after chronic administration of the cannabinoid receptor agonist WIN55,212-2. Int J Neuropsychopharmacol 2014; 18:pyu097. [PMID: 25522428 PMCID: PMC4438542 DOI: 10.1093/ijnp/pyu097] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Accepted: 11/14/2014] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The endocannabinoid system interacts extensively with other neurotransmitter systems and has been implicated in a variety of functions, including regulation of basal ganglia circuits and motor behavior. The present study examined the effects of repeated administration of the nonselective cannabinoid receptor 1 agonist WIN55,212-2 on locomotor activity and on binding and mRNA levels of dopamine receptors and transporters and GABAA receptors in mesostriatal dopaminergic regions of the rat. METHODS Rats received systemic injections of WIN55,212-2 (0, 0.1, 0.3, or 1mg/kg, intraperitoneally) for 20 consecutive days. Locomotor activity was measured on days 1, 10, and 20. Following the last measurement, rats were euthanized and prepared for in vitro binding and in situ hybridization experiments. RESULTS Acutely, 0.3 and 1mg/kg of WIN55,212-2 produced hypolocomotion, which was sustained for the next 2 measurements, compared to vehicle. Repeated administration of WIN55,212-2 decreased the mRNA levels of the D2 autoreceptors in substantia nigra and ventral tegmental area and increased D1 receptor mRNA and binding in nucleus accumbens. Furthermore, both dopamine receptor and transporter binding and mRNA levels were decreased in substantia nigra. Moreover, repeated administration of WIN55,212-2 decreased GABAA receptor binding levels in dorsal striatum and substantia nigra. CONCLUSIONS Our data indicate that chronic WIN55,212-2 administration results in sustained effects on locomotor activity, similar to those observed after acute administration, and modulates the dopaminergic and GABAergic systems in a region-, dose-, and neurotransmitter-selective manner.
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MESH Headings
- Animals
- Basal Ganglia/drug effects
- Basal Ganglia/metabolism
- Behavior, Animal/drug effects
- Benzoxazines/administration & dosage
- Benzoxazines/pharmacology
- Cannabinoid Receptor Agonists/administration & dosage
- Cannabinoid Receptor Agonists/pharmacology
- Dopamine Plasma Membrane Transport Proteins/genetics
- Dopamine Plasma Membrane Transport Proteins/metabolism
- Dopaminergic Neurons/drug effects
- Dopaminergic Neurons/metabolism
- Dose-Response Relationship, Drug
- Injections, Intraperitoneal
- Male
- Morpholines/administration & dosage
- Morpholines/pharmacology
- Motor Activity/drug effects
- Naphthalenes/administration & dosage
- Naphthalenes/pharmacology
- RNA, Messenger/metabolism
- Rats, Sprague-Dawley
- Receptor, Cannabinoid, CB1/agonists
- Receptor, Cannabinoid, CB1/metabolism
- Receptors, Dopamine D1/genetics
- Receptors, Dopamine D1/metabolism
- Receptors, Dopamine D2/genetics
- Receptors, Dopamine D2/metabolism
- Receptors, GABA-A/genetics
- Receptors, GABA-A/metabolism
- Time Factors
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Affiliation(s)
- Eleni Fanarioti
- University of Patras, Department of Biology, Laboratory of Human and Animal Physiology, Patras, Greece (Drs Fanarioti and Giompres); University of Crete, Department of Psychology, Laboratory of Behavioral Neuroscience, Rethymno, Crete, Greece (Drs Mavrikaki and Panagis); University of Patras, Department of Medicine, Laboratory of Physiology, Patras (Dr Mitsacos); Takeda Development Center Americas Inc., Deerfield, IL (Dr Nomikos)
| | - Maria Mavrikaki
- University of Patras, Department of Biology, Laboratory of Human and Animal Physiology, Patras, Greece (Drs Fanarioti and Giompres); University of Crete, Department of Psychology, Laboratory of Behavioral Neuroscience, Rethymno, Crete, Greece (Drs Mavrikaki and Panagis); University of Patras, Department of Medicine, Laboratory of Physiology, Patras (Dr Mitsacos); Takeda Development Center Americas Inc., Deerfield, IL (Dr Nomikos)
| | - George Panagis
- University of Patras, Department of Biology, Laboratory of Human and Animal Physiology, Patras, Greece (Drs Fanarioti and Giompres); University of Crete, Department of Psychology, Laboratory of Behavioral Neuroscience, Rethymno, Crete, Greece (Drs Mavrikaki and Panagis); University of Patras, Department of Medicine, Laboratory of Physiology, Patras (Dr Mitsacos); Takeda Development Center Americas Inc., Deerfield, IL (Dr Nomikos)
| | - Ada Mitsacos
- University of Patras, Department of Biology, Laboratory of Human and Animal Physiology, Patras, Greece (Drs Fanarioti and Giompres); University of Crete, Department of Psychology, Laboratory of Behavioral Neuroscience, Rethymno, Crete, Greece (Drs Mavrikaki and Panagis); University of Patras, Department of Medicine, Laboratory of Physiology, Patras (Dr Mitsacos); Takeda Development Center Americas Inc., Deerfield, IL (Dr Nomikos)
| | - George G Nomikos
- University of Patras, Department of Biology, Laboratory of Human and Animal Physiology, Patras, Greece (Drs Fanarioti and Giompres); University of Crete, Department of Psychology, Laboratory of Behavioral Neuroscience, Rethymno, Crete, Greece (Drs Mavrikaki and Panagis); University of Patras, Department of Medicine, Laboratory of Physiology, Patras (Dr Mitsacos); Takeda Development Center Americas Inc., Deerfield, IL (Dr Nomikos)
| | - Panagiotis Giompres
- University of Patras, Department of Biology, Laboratory of Human and Animal Physiology, Patras, Greece (Drs Fanarioti and Giompres); University of Crete, Department of Psychology, Laboratory of Behavioral Neuroscience, Rethymno, Crete, Greece (Drs Mavrikaki and Panagis); University of Patras, Department of Medicine, Laboratory of Physiology, Patras (Dr Mitsacos); Takeda Development Center Americas Inc., Deerfield, IL (Dr Nomikos).
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24
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Wakley AA, McBride AA, Vaughn LK, Craft RM. Cyclic ovarian hormone modulation of supraspinal Δ9-tetrahydrocannabinol-induced antinociception and cannabinoid receptor binding in the female rat. Pharmacol Biochem Behav 2014; 124:269-77. [DOI: 10.1016/j.pbb.2014.06.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Revised: 05/20/2014] [Accepted: 06/10/2014] [Indexed: 10/25/2022]
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25
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Laprairie RB, Bagher AM, Kelly MEM, Dupré DJ, Denovan-Wright EM. Type 1 cannabinoid receptor ligands display functional selectivity in a cell culture model of striatal medium spiny projection neurons. J Biol Chem 2014; 289:24845-62. [PMID: 25037227 DOI: 10.1074/jbc.m114.557025] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Modulation of type 1 cannabinoid receptor (CB1) activity has been touted as a potential means of treating addiction, anxiety, depression, and neurodegeneration. Different agonists of CB1 are known to evoke varied responses in vivo. Functional selectivity is the ligand-specific activation of certain signal transduction pathways at a receptor that can signal through multiple pathways. To understand cannabinoid-specific functional selectivity, different groups have examined the effect of individual cannabinoids on various signaling pathways in heterologous expression systems. In the current study, we compared the functional selectivity of six cannabinoids, including two endocannabinoids (2-arachidonyl glycerol (2-AG) and anandamide (AEA)), two synthetic cannabinoids (WIN55,212-2 and CP55,940), and two phytocannabinoids (cannabidiol (CBD) and Δ(9)-tetrahydrocannabinol (THC)) on arrestin2-, Gα(i/o)-, Gβγ-, Gα(s)-, and Gα(q)-mediated intracellular signaling in the mouse STHdh(Q7/Q7) cell culture model of striatal medium spiny projection neurons that endogenously express CB1. In this system, 2-AG, THC, and CP55,940 were more potent mediators of arrestin2 recruitment than other cannabinoids tested. 2-AG, AEA, and WIN55,212-2, enhanced Gα(i/o) and Gβγ signaling, with 2-AG and AEA treatment leading to increased total CB1 levels. 2-AG, AEA, THC, and WIN55,212-2 also activated Gα(q)-dependent pathways. CP55,940 and CBD both signaled through Gα(s). CP55,940, but not CBD, activated downstream Gα(s) pathways via CB1 targets. THC and CP55,940 promoted CB1 internalization and decreased CB1 protein levels over an 18-h period. These data demonstrate that individual cannabinoids display functional selectivity at CB1 leading to activation of distinct signaling pathways. To effectively match cannabinoids with therapeutic goals, these compounds must be screened for their signaling bias.
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Affiliation(s)
- Robert B Laprairie
- From the Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Amina M Bagher
- From the Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Melanie E M Kelly
- From the Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Denis J Dupré
- From the Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Eileen M Denovan-Wright
- From the Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
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26
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Hillard CJ. Stress regulates endocannabinoid-CB1 receptor signaling. Semin Immunol 2014; 26:380-8. [PMID: 24882055 DOI: 10.1016/j.smim.2014.04.001] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2014] [Accepted: 04/01/2014] [Indexed: 12/17/2022]
Abstract
The CB1 cannabinoid receptor is a G protein coupled receptor that is widely expressed throughout the brain. The endogenous ligands for the CB1 receptor (endocannabinoids) are N-arachidonylethanolamine and 2-arachidonoylglycerol; together the endocannabinoids and CB1R subserve activity dependent, retrograde inhibition of neurotransmitter release in the brain. Deficiency of CB1 receptor signaling is associated with anhedonia, anxiety, and persistence of negative memories. CB1 receptor-endocannabinoid signaling is activated by stress and functions to buffer or dampen the behavioral and endocrine effects of acute stress. Its role in regulation of neuronal responses is more complex. Chronic variable stress exposure reduces endocannabinoid-CB1 receptor signaling and it is hypothesized that the resultant deficiency in endocannabinoid signaling contributes to the negative consequences of chronic stress. On the other hand, repeated exposure to the same stress can sensitize CB1 receptor signaling, resulting in dampening of the stress response. Data are reviewed that support the hypothesis that CB1 receptor signaling is stress responsive and that maintaining robust endocannabinoid/CB1 receptor signaling provides resilience against the development of stress-related pathologies.
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Affiliation(s)
- Cecilia J Hillard
- Neuroscience Research Center, Medical College of Wisconsin, United States; Department of Pharmacology and Toxicology, Medical College of Wisconsin, United States.
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27
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Hillard CJ, Liu QS. Endocannabinoid signaling in the etiology and treatment of major depressive illness. Curr Pharm Des 2014; 20:3795-811. [PMID: 24180398 PMCID: PMC4002665 DOI: 10.2174/13816128113196660735] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 10/23/2013] [Indexed: 12/28/2022]
Abstract
The purpose of this review is to examine human and preclinical data that are relevant to the following hypotheses. The first hypothesis is that deficient CB1R-mediated signaling results in symptoms that mimic those seen in depression. The second hypothesis is that activation of CB1R-mediated signaling results in behavioral, endocrine and other effects that are similar to those produced by currently used antidepressants. The third hypothesis is that conventional antidepressant therapies act through enhanced CB1R mediated signaling. Together the available data indicate that activators of CB1R signaling, particularly inhibitors of fatty acid amide hydrolase, should be considered for clinical trials for the treatment of depression.
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MESH Headings
- Animals
- Antidepressive Agents/pharmacology
- Antidepressive Agents/therapeutic use
- Brain/drug effects
- Brain/enzymology
- Brain/metabolism
- Brain/pathology
- Cannabis
- Depressive Disorder, Major/drug therapy
- Depressive Disorder, Major/etiology
- Depressive Disorder, Major/genetics
- Depressive Disorder, Major/pathology
- Disease Models, Animal
- Endocannabinoids/genetics
- Endocannabinoids/metabolism
- Humans
- Magnetic Resonance Imaging
- Neurogenesis/drug effects
- Polymorphism, Genetic
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/metabolism
- Signal Transduction/drug effects
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Affiliation(s)
| | - Qing-song Liu
- Neuroscience Research Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226.
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28
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Cox RF, Rash V. Characterization of cannabinoid receptors. CURRENT PROTOCOLS IN PHARMACOLOGY 2013; 63:1.26.1-1.26.10. [PMID: 24510753 DOI: 10.1002/0471141755.ph0126s63] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
This unit describes the use of cannabinoid radioligands in competitive binding assays for determining affinity parameters (IC50, Ki ) of unlabeled compounds at transfected CB1 and CB2 receptors expressed in cell lines.
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Affiliation(s)
- Richard F Cox
- GlaxoSmithKline, Research Triangle Park, North Carolina
| | - Vincent Rash
- GlaxoSmithKline, Research Triangle Park, North Carolina
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29
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Abstract
Recently developed X-ray crystal structures of active state G-protein-coupled receptors have opened the way for detailed examination of the movement of the transmembrane (TM) helices and the specific residues involved in the receptor activation upon ligand binding. Previous modeling studies have indicated that the brain cannabinoid (CB1) receptor binds with a ligand at least in part through a hydrophobic tail on the ligand. This interaction is believed to be similar to the rotameric toggle switch proposed for the β2 adrenergic receptor (β2AR). In the present study, an active state model for the CB1 receptor, guided by the X-ray structure of the active state for β2AR, was constructed with HU210 bound as a ligand. Molecular dynamics (MD) simulations were employed to provide a smooth progression between inactive and active states of the receptor. This model was compared with our previously published CB1 receptor model to identify the functional residues that play key roles in triggering receptor conformational changes upon agonist binding. Movements in TM helices and functional residues are discussed. W279(5.43), contributing to an inward movement of the fifth TM helix (TM5) to the helical core, could serve as another rotameric switch for receptor activation. V282(5.46), interacting with the ligand's hydrophobic C3 alkyl chain, appears to play a key role in TM5 inward movement centered at L286(5.50) and subsequent coupling to V204(3.40). V204(3.40), closely interacting with the TM5 and TM6 hydrophobic patch residues in the middle of the receptor, particularly I290(5.54) and L352(6.44), appears to facilitate helical rearrangements, leading to the breakage of the ionic lock and the rotameric change of Y397(7.53), which are key features of the active state.
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30
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Chronic activation of cannabinoid receptors in vitro does not compromise mouse islet function. Clin Sci (Lond) 2013; 124:467-78. [PMID: 23078523 DOI: 10.1042/cs20120447] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We have demonstrated previously that mouse and human islets express ECS (endocannabinoid system) elements, and that short-term activation of islet cannabinoid CB1r and CB2r (cannabinoid type 1 and 2 receptors respectively) stimulates insulin secretion in vitro. There is evidence that the ECS is overactive in Type 2 diabetes, impairing glucose homoeostasis, but little is known about whether it is implicated in islet dysfunction. Therefore the aim of the present study was to investigate the effect of chronic exposure of isolated mouse islets to cannabinoid receptor agonists on islet gene expression and function. Quantitative RT-PCR (reverse transcription-PCR) indicated that mRNAs encoding synthesis [NAPE-PLD (N-acyl-phosphatidyl ethanolamide-hydrolysing phospholipase D)] and degradation [FAAH (fatty acid amide hydrolase)] of the endocannabinoid AEA (anandamide) were the most abundant ECS elements in mouse islets, with much lower levels of CB1r, CB2r, DAGL (diacylglycerol lipase) and MAGL (monoacylglycerol lipase) mRNAs. Maintenance of islets for up to 7 days in the presence of the CB1r agonist ACEA [N-(2-chloroethyl)-5Z,8Z,11Z,14Z-eiscosatetraenamide] or the CB2r agonist JWH015 [(2-methyl-1propyl-1H-indol3-yl)-1-napthalenylmethanone] did not compromise islet viability, as assessed by islet morphology and caspase activities, but there were some changes in mRNAs encoding ECS components. Neither glucose-stimulated insulin secretion nor acute insulin secretory responses to ACEA or JWH015 at 16 mM glucose were substantially modified by a 48 h or 7 day pre-exposure to these cannabinoid receptor agonists, but the stimulation of secretion at 3 mM glucose by 100 nM ACEA was significantly reduced after prolonged treatment with ACEA. Despite JWH015-induced reductions in islet glucagon content at 48 h and 7 days, there were no reductions in arginine-induced glucagon secretion from islets pre-exposed to JWH015 or ACEA. These data indicate that treatment of islets with agonists of CB1r and CB2r for up to 7 days does not have any major impact on islet function, suggesting that the impairments in glucose homoeostasis observed following overactivation of the ECS should be sought in relation to insulin resistance rather than β-cell dysfunction.
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31
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O'Brien LD, Wills KL, Segsworth B, Dashney B, Rock EM, Limebeer CL, Parker LA. Effect of chronic exposure to rimonabant and phytocannabinoids on anxiety-like behavior and saccharin palatability. Pharmacol Biochem Behav 2012; 103:597-602. [PMID: 23103902 DOI: 10.1016/j.pbb.2012.10.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 10/11/2012] [Accepted: 10/17/2012] [Indexed: 01/14/2023]
Abstract
The acute effects of cannabinoid compounds have been investigated in animal models of anxiety-like behavior and palatability processing. However, the chronic effects of cannabinoids in such models are poorly understood. Experiment 1 compared the effects of both acute and chronic (14 days) exposure to the CB(1) receptor inverse agonist/antagonist, rimonabant, and the cannabis-derived CB(1) receptor neutral antagonist, tetrahydrocannabivarin (THCV), on: 1) time spent in the open, lit box in the Light-Dark (LD) immersion model of anxiety-like behavior and 2) saccharin hedonic reactions in the taste reactivity (TR) test of palatability processing. Experiment 2 compared the effects of chronic administration of cannabis-derived Δ(9)-tetrahydrocannabinol (Δ(9)-THC), cannabidiol (CBD) and cannabigerol (CBG) in these models. Tests were administered on Days 1, 7 and 14 of drug administration. In Experiment 1, rimonabant, but not THCV, produced an anxiogenic-like reaction in the LD immersion test and reduced saccharin palatability in the TR test; both of these effects occurred acutely and were not enhanced by chronic exposure. In Experiment 2, Δ(9)-THC also produced an acute anxiogenic-like reaction in the LD immersion test, without enhancement by chronic exposure. However, Δ(9)-THC enhanced saccharin palatability in the TR test on Day 1 of drug exposure only. CBD and CBG did not modify anxiety-like responding, but CBG produced a weak enhancement of saccharin palatability on Day 1 only. The results suggest that the anxiogenic-like reactions and the suppression of hedonic responding produced by rimonabant, are mediated by inverse agonism of the CB(1) receptor and these effects are not enhanced with chronic exposure.
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Affiliation(s)
- Lesley D O'Brien
- Department of Psychology and Collaborative Neuroscience Program, University of Guelph, Guelph, ON, Canada N1G 2W1
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32
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Hillard CJ, Weinlander KM, Stuhr KL. Contributions of endocannabinoid signaling to psychiatric disorders in humans: genetic and biochemical evidence. Neuroscience 2011; 204:207-29. [PMID: 22123166 DOI: 10.1016/j.neuroscience.2011.11.020] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 11/05/2011] [Accepted: 11/08/2011] [Indexed: 11/28/2022]
Abstract
The endocannabinoid signaling system is a widespread, neuromodulatory system in brain and is also widely utilized in the periphery to modulate metabolic functions and the immune system. Preclinical data demonstrate that endocannabinoid signaling is an important stress buffer and modulates emotional and cognitive functions. These data suggest the hypothesis that endocannabinoid signaling could be dysfunctional in a number of mental disorders. Genetic polymorphisms in the human genes for two important proteins of the endocannabinoid signaling system, the CB1 cannabinoid receptor (CB1R) and fatty acid amide hydrolase (FAAH), have been explored in the context of normal and pathological conditions. In the case of the gene for FAAH, the mechanistic relationships among the common genetic polymorphism, the expression of the FAAH protein, and its likely impact on endocannabinoid signaling are understood. However, multiple polymorphisms in the gene for the CB1R occur and are associated with human phenotypic differences without an understanding of the functional relationships among the gene, mRNA, protein, and protein function. The endocannabinoid ligands are found in the circulation, and several studies have identified changes in their concentrations under various conditions. These data are reviewed for the purpose of generating hypotheses and to encourage further studies in this very interesting and important area.
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Affiliation(s)
- C J Hillard
- Department of Pharmacology and Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, WI, USA.
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33
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Suter TM, Chesterfield AK, Bao C, Schaus JM, Krushinski JH, Statnick MA, Felder CC. Pharmacological characterization of the cannabinoid CB1 receptor PET ligand ortholog, [3H]MePPEP. Eur J Pharmacol 2010; 649:44-50. [DOI: 10.1016/j.ejphar.2010.08.055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Revised: 08/13/2010] [Accepted: 08/31/2010] [Indexed: 10/19/2022]
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34
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Vaughn LK, Denning G, Stuhr KL, de Wit H, Hill MN, Hillard CJ. Endocannabinoid signalling: has it got rhythm? Br J Pharmacol 2010; 160:530-43. [PMID: 20590563 DOI: 10.1111/j.1476-5381.2010.00790.x] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Endogenous cannabinoid signalling is widespread throughout the body, and considerable evidence supports its modulatory role in many fundamental physiological processes. The daily and seasonal cycles of the relationship of the earth and sun profoundly affect the terrestrial environment. Terrestrial species have adapted to these cycles in many ways, most well studied are circadian rhythms and hibernation. The purpose of this review was to examine literature support for three hypotheses: (i) endocannabinoid signalling exhibits brain region-specific circadian rhythms; (ii) endocannabinoid signalling modulates the rhythm of circadian processes in mammals; and (iii) changes in endocannabinoid signalling contribute to the state of hibernation. The results of two novel studies are presented. First, we report the results of a study of healthy humans demonstrating that plasma concentrations of the endocannabinoid, N-arachidonylethanolamine (anandamide), exhibit a circadian rhythm. Concentrations of anandamide are threefold higher at wakening than immediately before sleep, a relationship that is dysregulated by sleep deprivation. Second, we investigated differences in endocannabinoids and congeners in plasma from Marmota monax obtained in the summer and during the torpor state of hibernation. We report that 2-arachidonoylglycerol is below detection in M. monax plasma and that concentrations of anandamide are not different. However, plasma concentrations of the anorexigenic lipid oleoylethanolamide were significantly lower in hibernation, while the concentrations of palmitoylethanolamide and 2-oleoylglycerol were significantly greater in hibernation. We conclude that available data support a bidirectional relationship between endocannabinoid signalling and circadian processes, and investigation of the contribution of endocannabinoid signalling to the dramatic physiological changes that occur during hibernation is warranted.
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Affiliation(s)
- Linda K Vaughn
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, USA
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35
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Hill MN, Titterness AK, Morrish AC, Carrier EJ, Lee TTY, Gil-Mohapel J, Gorzalka BB, Hillard CJ, Christie BR. Endogenous cannabinoid signaling is required for voluntary exercise-induced enhancement of progenitor cell proliferation in the hippocampus. Hippocampus 2010; 20:513-23. [PMID: 19489006 DOI: 10.1002/hipo.20647] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Voluntary exercise and endogenous cannabinoid activity have independently been shown to regulate hippocampal plasticity. The aim of the current study was to determine whether the endocannabinoid system is regulated by voluntary exercise and if these changes contribute to exercise-induced enhancement of cell proliferation. In Experiment 1, 8 days of free access to a running wheel increased the agonist binding site density of the cannabinoid CB(1) receptor; CB(1) receptor-mediated GTPgammaS binding; and the tissue content of the endocannabinoid anandamide in the hippocampus but not in the prefrontal cortex. In Experiment 2, the CB(1) receptor antagonist AM251 (1 mg kg(-1)) was administered daily to animals given free access to a running wheel for 8 days, after which cell proliferation in the hippocampus was examined through immunohistochemical analysis of the cell cycle protein Ki-67. Voluntary exercise increased proliferation of progenitor cells, as evidenced by the increase in the number of Ki-67 positive cells in the granule cell layer of the dentate gyrus (DG) in the hippocampus. However, this effect was abrogated by concurrent treatment with AM251, indicating that the increase in endocannabinoid signaling in the hippocampus is required for the exercise-induced increase in cell proliferation. These data demonstrate that the endocannabinoid system in the hippocampus is sensitive to environmental change and suggest that it is a mediator of experience-induced plasticity.
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Affiliation(s)
- Matthew N Hill
- Department of Psychology, University of British Columbia, Vancouver, B.C., Canada.
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36
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Characterization of active and inactive states of CB1 receptor and the differential binding state modulation by cannabinoid agonists, antagonists and inverse agonists. Neuropharmacology 2010; 58:1215-9. [DOI: 10.1016/j.neuropharm.2010.03.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Revised: 12/24/2009] [Accepted: 03/01/2010] [Indexed: 11/22/2022]
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37
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Bosier B, Muccioli GG, Hermans E, Lambert DM. Functionally selective cannabinoid receptor signalling: therapeutic implications and opportunities. Biochem Pharmacol 2010; 80:1-12. [PMID: 20206137 DOI: 10.1016/j.bcp.2010.02.013] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Revised: 02/17/2010] [Accepted: 02/24/2010] [Indexed: 10/19/2022]
Abstract
The CB(1) and CB(2) cannabinoid receptors are G protein-coupled receptors (GPCRs) recognized by a variety of endogenous ligands and activating multiple signalling pathways. This multiplicity of ligands and intracellular transduction mechanisms supports a complex control of physiological functions by the endocannabinoid system, but requires a finely tuned regulation of the signalling events triggered on receptor activation. Here we review the diverse signalling pathways activated by the cannabinoid receptors and discuss the mechanisms allowing for specificity in the associated functional responses triggered by endogenous or exogenous ligands. At variance with the classical concept that all agonists at a given GPCR induce a similar repertoire of downstream events in all tissues, we also summarize the experimental evidence supporting the existence of functional selectivity and protean agonism at cannabinoid receptors. By placing emphasis on the ligand- or constitutive activity-dependent specifications of receptor-G protein coupling, these concepts explain how distinct cannabinoid ligands may activate specific downstream mediators. Finally, although both the diversity and specificity in cannabinoid signalling are now established in vitro, few data are available from in vivo studies. Therefore, we conclude this review by examining the experimental evidence supporting the physiological relevance of this complexity in the cannabinoid system. The ability to selectively manipulate physiological functions, through activation of defined signalling cascades, will in all likelihood help in the development of efficacious and safe cannabinoid-based therapeutics for a variety of indications.
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Affiliation(s)
- Barbara Bosier
- Unité de Chimie Pharmaceutique et de Radiopharmacie (CMFA 7340), Louvain Drug Research Institute, Brussels, Belgium
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38
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Reggio PH. Toward the design of cannabinoid CB1 receptor inverse agonists and neutral antagonists. Drug Dev Res 2009. [DOI: 10.1002/ddr.20337] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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39
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Hill MN, McLaughlin RJ, Morrish AC, Viau V, Floresco SB, Hillard CJ, Gorzalka BB. Suppression of amygdalar endocannabinoid signaling by stress contributes to activation of the hypothalamic-pituitary-adrenal axis. Neuropsychopharmacology 2009; 34:2733-45. [PMID: 19710634 PMCID: PMC3197779 DOI: 10.1038/npp.2009.114] [Citation(s) in RCA: 216] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Endocannabinoids inhibit hypothalamic-pituitary-adrenal (HPA) axis activity; however, the neural substrates and pathways subserving this effect are not well characterized. The amygdala is a forebrain structure that provides excitatory drive to the HPA axis under conditions of stress. The aim of this study was to determine the contribution of endocannabinoid signaling within distinct amygdalar nuclei to activation of the HPA axis in response to psychological stress. Exposure of rats to 30-min restraint stress increased the hydrolytic activity of fatty acid amide hydrolase (FAAH) and concurrently decreased content of the endocannabinoid/CB(1) receptor ligand N-arachidonylethanolamine (anandamide; AEA) throughout the amygdala. In stressed rats, AEA content in the amygdala was inversely correlated with serum corticosterone concentrations. Pharmacological inhibition of FAAH activity within the basolateral amygdala complex (BLA) attenuated stress-induced corticosterone secretion; this effect was blocked by co-administration of the CB(1) receptor antagonist AM251, suggesting that stress-induced decreases in CB(1) receptor activation by AEA contribute to activation of the neuroendocrine stress response. Local administration into the BLA of a CB(1) receptor agonist significantly reduced stress-induced corticosterone secretion, whereas administration of a CB(1) receptor antagonist increased corticosterone secretion. Taken together, these findings suggest that the degree to which stressful stimuli reduce amygdalar AEA/CB(1) receptor signaling contributes to the magnitude of the HPA response.
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Affiliation(s)
- Matthew N Hill
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada.
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Marco EM, Rubino T, Adriani W, Viveros MP, Parolaro D, Laviola G. Long-term consequences of URB597 administration during adolescence on cannabinoid CB1 receptor binding in brain areas. Brain Res 2009; 1257:25-31. [DOI: 10.1016/j.brainres.2008.12.037] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Revised: 12/11/2008] [Accepted: 12/14/2008] [Indexed: 11/17/2022]
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Mikami T, Sugimoto H, Naganeo R, Ohmi T, Saito T, Eda H. Contribution of active and inactive states of the human 5-HT4d receptor to the functional activities of 5-HT4-receptor agonists. J Pharmacol Sci 2008; 107:251-9. [PMID: 18587219 DOI: 10.1254/jphs.fp0072230] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
In the present study, binding affinities of 5-hydroxytryptamine-4 (5-HT(4)) ligands for the human 5-HT(4d) receptor were determined using the agonist [(3)H]5-HT and the selective 5-HT(4) antagonist [(3)H]GR113,808. We also compared the affinity differences between [(3)H]5-HT binding (K(H)) and [(3)H]GR113,808 binding (K(L)) with their activities as 5-HT(4) ligands. Binding studies using [(3)H]5-HT revealed that the human 5-HT(4d) receptor has two binding sites, whereas [(3)H]GR113,808 yielded a single binding site. Additionally, the number of [(3)H]5-HT binding sites decreased in the presence of guanosine-5'-O-(3-thiotriphosphate) (GTPgammaS), but the number of [(3)H]GR113,808 sites did not change. In competitive binding assays, full agonists such as 5-methoxytryptamine and tegaserod showed 2- to 8-fold higher affinities for [(3)H]5-HT binding (K(H)) than for [(3)H]GR113,808 binding (K(L)) (K(H)<K(L)). Conversely, antagonists showed lower affinities for [(3)H]5-HT binding than for [(3)H]GR113,808 binding (K(H)>K(L)). Finally, partial agonists displayed similar binding affinities for both radioligands (K(H) = K(L)). These findings suggest that the equilibrium between active and inactive states of the human 5-HT(4d) receptor relies on the functional activities of 5-HT(4) ligands, and these states affect the affinities of 5-HT(4) ligands in the competitive binding assay.
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Affiliation(s)
- Tadayoshi Mikami
- Discovery Biology Research, Global Research & Development, Nagoya Laboratories, Pfizer Japan Inc., Taketoyo, Aichi, Japan
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Hillard CJ, Ho WS, Thompson J, Gauthier KM, Wheelock CE, Huang H, Hammock BD. Inhibition of 2-arachidonoylglycerol catabolism modulates vasoconstriction of rat middle cerebral artery by the thromboxane mimetic, U-46619. Br J Pharmacol 2007; 152:691-8. [PMID: 17891162 PMCID: PMC2190024 DOI: 10.1038/sj.bjp.0707468] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND AND PURPOSE Cerebrovascular smooth muscle cells express the CB1 cannabinoid receptor and CB1 agonists produce vasodilatation of the middle cerebral artery (MCA). The thromboxane A2 mimetic, U-46619, increased the content of the endocannabinoid, 2-arachidonoylglycerol (2-AG) in the MCA and 2-AG moderated the vasoconstriction produced by U46619 in this tissue. The purposes of this study were to examine the extent to which 2-AG is catabolized by cerebral arteries and to determine whether blockade of 2-AG inactivation potentiates its feedback inhibition of U-44619-mediated vasoconstriction. EXPERIMENTAL APPROACH The diameters of isolated, perfused MCA from male rats were measured using videomicroscopy. KEY RESULTS Exogenous 2-AG produces a CB1 receptor-dependent and concentration-related increase in the diameter of MCA constricted with 5-HT. The E (max) for 2-AG dilation is increased 4-fold in the presence of the metabolic inhibitors 3-(decylthio)-1,1,1-trifluropropan-2-one (DETFP), URB754 and URB597. To examine the role of catabolism in the effects of endogenous 2-AG, vasoconstriction induced by U-46619 was studied. DETFP and URB754, but not the fatty acid amide hydrolase inhibitor, URB597, significantly increased the EC(50) for U-46619. These data support a physiological role for endocannabinoid feedback inhibition in the effects of U-46619 and indicate that endogenously produced 2-AG is also efficiently catabolized within the MCA. CONCLUSIONS AND IMPLICATIONS MCA express mechanisms for the efficient inactivation of 2-AG, providing further support for an endocannabinoid feedback mechanism that opposes thromboxane-mediated vasoconstriction. These data suggest that potentiation of endogenously produced 2-AG could be a novel therapeutic approach to the treatment of thrombotic stroke.
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Affiliation(s)
- C J Hillard
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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Abstract
Over the past 50 years, a considerable research in medicinal chemistry has been carried out around the natural constituents of Cannabis sativa L. Following the identification of Delta9-tetrahydrocannabinol (Delta9-THC) in 1964, critical chemical modifications, e.g., variation of the side chain at C3 and the opening of the tricyclic scaffold, have led to the characterization of potent and cannabinoid receptor subtype-selective ligands. Those ligands that demonstrate high affinity for the cannabinoid receptors and good biological efficacy are still used as powerful pharmacological tools. This review summarizes past as well as recent developments in the structure-activity relationships of phytocannabinoids.
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Affiliation(s)
- Eric Stern
- Drug Design and Discovery Center and Unité de Chimie pharmaceutique et de Radiopharmacie, Ecole de Pharmacie, Faculté de Médecine, Université catholique de Louvain, Avenue E. Mounier 73, U.C.L. 73.40, B-1200 Bruxelles
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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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Anavi-Goffer S, Fleischer D, Hurst DP, Lynch DL, Barnett-Norris J, Shi S, Lewis DL, Mukhopadhyay S, Howlett AC, Reggio PH, Abood ME. Helix 8 Leu in the CB1 cannabinoid receptor contributes to selective signal transduction mechanisms. J Biol Chem 2007; 282:25100-13. [PMID: 17595161 DOI: 10.1074/jbc.m703388200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The intracellular C-terminal helix 8 (H8) of the CB(1) cannabinoid receptor deviates from the highly conserved NPXXY(X)(5,6)F G-protein-coupled receptor motif, possessing a Leu instead of a Phe. We compared the signal transduction capabilities of CB(1) with those of an L7.60F mutation and an L7.60I mutation that mimics the CB(2) sequence. The two mutant receptors differed from wild type (WT) in their ability to regulate G-proteins in the [(35)S]guanosine 5'-3-O-(thio)triphosphate binding assay. The L7.60F receptor exhibited attenuated stimulation by agonists WIN-55,212-2 and CP-55,940 but not HU-210, whereas the L7.60I receptor exhibited impaired stimulation by all agonists tested as well as by the inverse agonist rimonabant. The mutants internalized more rapidly than WT receptors but could equally sequester G-proteins from the somatostatin receptor. Both the time course and maximal N-type Ca(2+) current inhibition by WIN-55,212-2 were reduced in the mutants. Reconstitution experiments with pertussis toxin-insensitive G-proteins revealed loss of coupling to Galpha(i3) but not Galpha(0A) in the L7.60I mutant, whereas the reduction in the time course for the L7.60F mutant was governed by Galpha(i3). Furthermore, Galpha(i3) but not Galpha(0A) enhanced basal facilitation ratio, suggesting that Galpha(i3) is responsible for CB(1) tonic activity. Co-immunoprecipitation studies revealed that both mutant receptors were associated with Galpha(i1) or Galpha(i2) but not with Galpha(i3). Molecular dynamics simulations of WT CB(1) receptor and each mutant in a 1-palmitoyl-2-oleoylphosphatidylcholine bilayer suggested that the packing of H8 is different in each. The hydrogen bonding patterns along the helix backbones of each H8 also are different, as are the geometries of the elbow region of H8 (R7.56(400)-K7.58(402)). This study demonstrates that the evolutionary modification to NPXXY(X)(5,6)L contributes to maximal activity of the CB(1) receptor and provides a molecular basis for the differential coupling observed with chemically different agonists.
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Affiliation(s)
- Sharon Anavi-Goffer
- California Pacific Medical Center Research Institute, San Francisco, California 94107, USA
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Hill MN, Barr AM, Ho WSV, Carrier EJ, Gorzalka BB, Hillard CJ. Electroconvulsive shock treatment differentially modulates cortical and subcortical endocannabinoid activity. J Neurochem 2007; 103:47-56. [PMID: 17561935 DOI: 10.1111/j.1471-4159.2007.04688.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Previous studies indicate that the endocannabinoid system is a potential target for the treatment of depression. To further examine this question we assessed the effects of electroconvulsive shock (ECS) treatment, both a single session and 10 daily sessions, on endocannabinoid content, CB(1) receptor binding parameters and CB(1) receptor-mediated [(35)S]GTPgammaS binding in the prefrontal cortex, hippocampus, hypothalamus and amygdala. A single ECS session resulted in a general reduction in the binding affinity of the CB(1) receptor in all brain regions examined, as well as reductions in N-arachidonylethanolamine (anandamide) content in the prefrontal cortex and the hippocampus, reduced hydrolysis of anandamide by fatty acid amide hydrolase (FAAH) in the prefrontal cortex and an increase in the binding site density of the CB(1) receptor in the amygdala. Following 10 ECS sessions, all these effects subsided except for the reductions in anandamide content in the prefrontal cortex, which increased in magnitude, as well as the reductions in FAAH activity in the prefrontal cortex. Additionally, repeated ECS treatment resulted in a significant reduction in the binding site density of the CB(1) receptor in the prefrontal cortex, but did not alter CB(1) receptor-mediated [(35)S]GTPgammaS binding. Repeated ECS treatment also significantly enhanced the sensitivity of CB(1) receptor-mediated [(35)S]GTPgammaS binding in the amygdala. Collectively, these data demonstrate that ECS treatment results in a down-regulation of cortical and an up-regulation of subcortical endocannabinoid activity, illustrating the possibility that the role of the endocannabinoid system in affective illness may be both complex and regionally specific.
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Affiliation(s)
- Matthew N Hill
- Department of Psychology, University of British Columbia, Vancouver, British Columbia, Canada
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Basavarajappa BS. Neuropharmacology of the endocannabinoid signaling system-molecular mechanisms, biological actions and synaptic plasticity. Curr Neuropharmacol 2007; 5:81-97. [PMID: 18084639 PMCID: PMC2139910 DOI: 10.2174/157015907780866910] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2006] [Revised: 02/07/2007] [Accepted: 02/14/2007] [Indexed: 11/22/2022] Open
Abstract
The endocannabinoid signaling system is composed of the cannabinoid receptors; their endogenous ligands, the endocannabinoids; the enzymes that produce and inactivate the endocannabinoids; and the endocannabinoid transporters. The endocannabinoids are a new family of lipidic signal mediators, which includes amides, esters, and ethers of long-chain polyunsaturated fatty acids. Endocannabinoids signal through the same cell surface receptors that are targeted by Delta(9)-tetrahydrocannabinol (Delta(9)THC), the active principles of cannabis sativa preparations like hashish and marijuana. The biosynthetic pathways for the synthesis and release of endocannabinoids are still rather uncertain. Unlike neurotransmitter molecules that are typically held in vesicles before synaptic release, endocannabinoids are synthesized on demand within the plasma membrane. Once released, they travel in a retrograde direction and transiently suppress presynaptic neurotransmitter release through activation of cannabinoid receptors. The endocannabinoid signaling system is being found to be involved in an increasing number of pathological conditions. In the brain, endocannabinoid signaling is mostly inhibitory and suggests a role for cannabinoids as therapeutic agents in central nervous system (CNS) disease. Their ability to modulate synaptic efficacy has a wide range of functional consequences and provides unique therapeutic possibilities. The present review is focused on new information regarding the endocannabinoid signaling system in the brain. First, the structure, anatomical distribution, and signal transduction mechanisms of cannabinoid receptors are described. Second, the synthetic pathways of endocannabinoids are discussed, along with the putative mechanisms of their release, uptake, and degradation. Finally, the role of the endocannabinoid signaling system in the CNS and its potential as a therapeutic target in various CNS disease conditions, including alcoholism, are discussed.
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Affiliation(s)
- Balapal S Basavarajappa
- Division of Analytical Psychopharmacology, New York State Psychiatric Institute, New York, NY 10032, USA.
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48
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Abstract
Convincing evidence from preclinical studies demonstrates that cannabinoids can reduce pain responses in a range of inflammatory and neuropathic pain models. The anatomical and functional data reveal cannabinoid receptor-mediated analgesic actions operating at sites concerned with the transmission and processing of nociceptive signals in brain, spinal cord and the periphery. The precise signalling mechanisms by which cannabinoids produce analgesic effects at these sites remain unclear; however, significant clues point to cannabinoid modulation of the functions of neurone and immune cells that mediate nociceptive and inflammatory responses. Intracellular signalling mechanisms engaged by cannabinoid receptors-like the inhibition of calcium transients and adenylate cyclase, and pre-synaptic modulation of transmitter release-have been demonstrated in some of these cell types and are predicted to play a role in the analgesic effects of cannabinoids. In contrast, the clinical effectiveness of cannabinoids as analgesics is less clear. Progress in this area requires the development of cannabinoids with a more favourable therapeutic index than those currently available for human use, and the testing of their efficacy and side-effects in high-quality clinical trials.
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Affiliation(s)
- I J Lever
- Pain Research Group, Department of Anaesthetics, Intensive Care and Pain Medicine, Imperial College London, Chelsea and Westminster Hospital Campus, 369 Fulham Road, London SW10 9NH, UK
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D'Antona AM, Ahn KH, Kendall DA. Mutations of CB1 T210 produce active and inactive receptor forms: correlations with ligand affinity, receptor stability, and cellular localization. Biochemistry 2006; 45:5606-17. [PMID: 16634642 PMCID: PMC2667143 DOI: 10.1021/bi060067k] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Human cannabinoid receptor 1 (CB(1)) has attracted substantial interest as a potential therapeutic target for treating obesity and other obsessive disorders. An understanding of the mechanism governing the transition of the CB(1) receptor between its inactive and active states is critical for understanding how therapeutics can selectively regulate receptor activity. We have examined the importance of the Thr at position 210 in CB(1) in this transition, a residue predicted to be on the same face of the helix as the Arg of the DRY motif highly conserved in the G protein-coupled receptor superfamily. This Thr was substituted with Ile and Ala via mutagenesis, and the receptors, T210I and T210A, were expressed in HEK 293 cells. The T210I receptor exhibited enhanced agonist and diminished inverse agonist affinity relative to the wild type, consistent with a shift toward the active form. However, treatment with GTPgammaS to inhibit G protein coupling diminished the affinity change for the inverse agonist SR141716A. The decreased thermal stability of the T210I receptor and increased level of internalization of a T210I receptor-GFP chimera were also observed, consistent with constitutive activity. In contrast, the T210A receptor exhibited the opposite profile: diminished agonist and enhanced inverse agonist affinity. The T210A receptor was found to be more thermally stable than the wild type, and high levels of a T210A receptor-GFP chimera were localized to the cell surface as predicted for an inactive receptor form. These results suggest that T210 plays a key role in governing the transition between inactive and active CB(1) receptor states.
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Affiliation(s)
- Aaron M D'Antona
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269-3125, USA
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50
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Patel S, Hillard CJ. Pharmacological evaluation of cannabinoid receptor ligands in a mouse model of anxiety: further evidence for an anxiolytic role for endogenous cannabinoid signaling. J Pharmacol Exp Ther 2006; 318:304-11. [PMID: 16569753 DOI: 10.1124/jpet.106.101287] [Citation(s) in RCA: 293] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Extracts of Cannabis sativa have been used for their calming and sedative effects for centuries. Recent developments in drug discovery have suggested that modulation of neuronal endogenous cannabinoid signaling systems could represent a novel approach to the treatment of anxiety-related disorders while minimizing the adverse effects of direct acting cannabinoid receptor agonists. In this study, we evaluated the effects of direct cannabinoid receptor agonists and antagonists and endocannabinoid-modulating drugs on anxiety-like behavior in mice using the elevated-plus maze. We found that the direct CB1 receptor agonists (1R,3R,4R)-3-[2-hydroxy-4-(1,1-dimethylheptyl)phenyl]-4-(3-hydroxypropyl)cyclohexan-1-ol (CP 55,940) (0.001-0.3 mg/kg) and 2,3-dihydro-5-methyl-3[(4-morpholinyl)methyl]pyrrolo [1,2,3-de]-1,4-benzoxazinyl]-(1-naphthalenyl)methanone mesylate) (WIN 55212-2) (0.3-10 mg/kg) increased time spent on the open arms (To) at low doses only. At the highest doses tested, both compounds altered overall locomotor activity. In contrast, Delta9-tetrahydrocannabinol (0.25-10 mg/kg) produced a dose-dependent reduction in To. The endocannabinoid uptake/catabolism inhibitor 4-hydroxyphenylarachidonylamide (AM404) (0.3-10 mg/kg) produced an increase in To at low doses and had no effect at the highest dose tested. The fatty acid amide hydrolase inhibitor cyclohexyl carbamic acid 3'-carbamoyl-biphenyl-3-yl ester (URB597) (0.03-0.3 mg/kg) produced a monophasic, dose-dependent increase in To. The CB1 receptor antagonists N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide HCl (SR141716) (1-10 mg/kg) and N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (AM251) (1-10 mg/kg) produced dose-related decreases in To. These data indicate that activation of CB1 cannabinoid receptors reduces anxiety-like behaviors in mice and further support an anxiolytic role for endogenous cannabinoid signaling. These results suggest that pharmacological modulation of this system could represent a new approach to the treatment of anxiety-related psychiatric disorders.
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Affiliation(s)
- Sachin Patel
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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