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Crane NA, Phan KL. Effect of Δ9-Tetrahydrocannabinol on frontostriatal resting state functional connectivity and subjective euphoric response in healthy young adults. Drug Alcohol Depend 2021; 221:108565. [PMID: 33592558 PMCID: PMC8026570 DOI: 10.1016/j.drugalcdep.2021.108565] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 12/16/2020] [Accepted: 01/06/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND Few studies have examined how Δ9-Tetrahydrocannabinol (THC), the main psychoactive component of cannabis, impacts brain reward circuitry in humans. In this study, we examined if an acute dose of THC altered resting state functional connectivity between the striatum and prefrontal cortex among healthy young adults with limited cannabis use. METHODS Participants received THC (n = 24) or placebo (n = 22) in a double-blind, randomized, between-subject design. Participants completed self-report measures of euphoria and drug-liking throughout the visit. Approximately 120 min after drug administration, participants completed an 8-min resting state functional MRI (rs-fMRI) scan. We utilized seed-based connectivity of the striatum (bilateral putamen, caudate, and NAcc seeds) to the frontal cortex. RESULTS Individuals who received THC demonstrated greater rs-fMRI connectivity between the right NAcc and regions of the medial prefrontal cortex (mPFC) (p-values<0.05, corrected) and higher subjective euphoria ratings (p = .03) compared to compared to individuals who received placebo. Higher ratings of euphoria were related to greater right NAcc-dorsal mPFC (dmPFC) connectivity for the THC group (p=.03), but not for the placebo group (p=.98). CONCLUSIONS This is one of the first studies to examine rs-fMRI connectivity in healthy young non-users after THC administration. We found individuals receiving THC show greater rs-fMRI connectivity between the NAcc and mPFC, regions implicated in reward, compared to individuals receiving placebo. In addition, individuals receiving THC reported higher subjective euphoria ratings, which were positively associated with NAcc-dmPFC connectivity. Overall, our findings suggest THC may produce subjective and neural reward responses that contribute to the rewarding, reinforcing properties of cannabis.
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Affiliation(s)
| | - K. Luan Phan
- Department of Psychiatry, University of Illinois at
Chicago,Department of Psychiatry and Behavioral Health, The Ohio
State University
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Abstract
Addiction is commonly identified with habitual nonmedical self-administration of drugs. It is usually defined by characteristics of intoxication or by characteristics of withdrawal symptoms. Such addictions can also be defined in terms of the brain mechanisms they activate; most addictive drugs cause elevations in extracellular levels of the neurotransmitter dopamine. Animals unable to synthesize or use dopamine lack the conditioned reflexes discussed by Pavlov or the appetitive behavior discussed by Craig; they have only unconditioned consummatory reflexes. Burst discharges (phasic firing) of dopamine-containing neurons are necessary to establish long-term memories associating predictive stimuli with rewards and punishers. Independent discharges of dopamine neurons (tonic or pacemaker firing) determine the motivation to respond to such cues. As a result of habitual intake of addictive drugs, dopamine receptors expressed in the brain are decreased, thereby reducing interest in activities not already stamped in by habitual rewards.
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Affiliation(s)
- Roy A Wise
- National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland 21224, USA; .,Behavioral Genetics Laboratory, McLean Hospital, Belmont, Massachusetts 02478, USA;
| | - Mykel A Robble
- Behavioral Genetics Laboratory, McLean Hospital, Belmont, Massachusetts 02478, USA;
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Woodcock EA, Zakiniaeiz Y, Morris ED, Cosgrove KP. Sex and the dopaminergic system: Insights from addiction studies. HANDBOOK OF CLINICAL NEUROLOGY 2020; 175:141-165. [PMID: 33008522 PMCID: PMC11267480 DOI: 10.1016/b978-0-444-64123-6.00011-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Sex differences are present in psychiatric disorders associated with disrupted dopamine function, and thus, sex differences in dopamine neurobiology may underlie these clinical disparities. In this chapter, we review sex differences in the dopaminergic system with a focus on substance use disorders, especially tobacco smoking, as our exemplar disorder. This chapter is organized into five sections describing sex differences in the dopaminergic system: (1) neurobiology, (2) role of sex hormones, (3) genetic underpinnings, (4) cognitive function, and (5) influence on addiction. In each section, we provide an overview of the topic area, summarize sex differences identified to date, highlight addiction research, especially clinical neuroimaging studies, and suggest avenues for future research.
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Affiliation(s)
- Eric A Woodcock
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, United States; Department of Psychiatry, Yale School of Medicine, New Haven, CT, United States; Yale Positron Emission Tomography (PET) Center, Yale University, New Haven, CT, United States
| | - Yasmin Zakiniaeiz
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, United States; Yale Positron Emission Tomography (PET) Center, Yale University, New Haven, CT, United States
| | - Evan D Morris
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, United States; Department of Psychiatry, Yale School of Medicine, New Haven, CT, United States; Department of Biomedical Engineering, Yale University, New Haven, CT, United States; Department of Biomedical Engineering, Yale University, New Haven, CT, United States; Invicro, LLC, New Haven, CT, United States
| | - Kelly P Cosgrove
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, United States; Department of Psychiatry, Yale School of Medicine, New Haven, CT, United States; Yale Positron Emission Tomography (PET) Center, Yale University, New Haven, CT, United States.
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Gupta S, De Aquino JP, D'Souza DC, Ranganathan M. Effects of haloperidol on the delta-9-tetrahydrocannabinol response in humans: a responder analysis. Psychopharmacology (Berl) 2019; 236:2635-2640. [PMID: 30919005 PMCID: PMC6697616 DOI: 10.1007/s00213-019-05235-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 03/19/2019] [Indexed: 12/12/2022]
Abstract
RATIONALE Δ-9-Tetrahydrocannabinol (Δ-9-THC) produces psychotomimetic effects in humans. However, the role of dopamine signaling in producing such effects is unclear. We hypothesized that dopaminergic antagonism would reduce the psychotomimetic effect of Δ-9-THC. OBJECTIVE The objective of this study was to evaluate whether pre-treatment with haloperidol would alter the psychotomimetic and perceptual-altering effects of Δ-9-THC, measured by the Positive and Negative Syndrome Scale for Schizophrenia (PANSS) and the Clinician-Administered Dissociative Symptom Scale (CADSS) in humans. METHODS In a two-test-day double-blind study, 28 healthy individuals were administered with active (0.057 mg/kg) or placebo oral haloperidol, followed 90 and 215 min later by intravenous administration of active (0.0286 mg/kg) Δ-9-THC and placebo, respectively. This secondary analysis was conducted because of the observation in other studies and in our data that a significant proportion of individuals may not have an adequate response to THC (floor effect), thus limiting the ability to test an interaction. Therefore, this analysis was performed including only responders to THC (n = 10), defined as individuals who had an increase of at least one point on the PANSS positive scale, consistent with prior human laboratory studies. RESULTS In the 10 responders, Δ-9-THC-induced increases in PANSS positive scores were significantly lower in the haloperidol condition (1.1 + 0.35) compared with the placebo condition (2.9 + 0.92). CONCLUSION This responder analysis showed that haloperidol did reduce the psychotomimetic effect of Δ-9-THC, supporting the hypothesis that dopaminergic signaling may participate in the psychosis-like effects of cannabinoids.
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Affiliation(s)
- Swapnil Gupta
- Department of Psychiatry, Yale University School of Medicine, 300 George St, Suite 901, New Haven, CT, 06510, USA
- Connecticut Mental Health Center, 34 Park St, New Haven, CT, USA
| | - Joao P De Aquino
- Department of Psychiatry, Yale University School of Medicine, 300 George St, Suite 901, New Haven, CT, 06510, USA.
- Clinical Neuroscience Research Unit, Connecticut Mental Health Center, 34 Park St, 3rd Floor, New Haven, CT, USA.
- VA Connecticut Healthcare System, Clinical Neurosciences Division, U.S. Department of Veterans Affairs, West Haven, CT, USA.
| | - Deepak C D'Souza
- Department of Psychiatry, Yale University School of Medicine, 300 George St, Suite 901, New Haven, CT, 06510, USA
- Clinical Neuroscience Research Unit, Connecticut Mental Health Center, 34 Park St, 3rd Floor, New Haven, CT, USA
- VA Connecticut Healthcare System, Clinical Neurosciences Division, U.S. Department of Veterans Affairs, West Haven, CT, USA
| | - Mohini Ranganathan
- Department of Psychiatry, Yale University School of Medicine, 300 George St, Suite 901, New Haven, CT, 06510, USA
- Clinical Neuroscience Research Unit, Connecticut Mental Health Center, 34 Park St, 3rd Floor, New Haven, CT, USA
- VA Connecticut Healthcare System, Clinical Neurosciences Division, U.S. Department of Veterans Affairs, West Haven, CT, USA
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Cannabinoid CB 1 receptor neutral antagonist AM4113 inhibits heroin self-administration without depressive side effects in rats. Acta Pharmacol Sin 2019; 40:365-373. [PMID: 29967454 DOI: 10.1038/s41401-018-0059-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Accepted: 05/31/2018] [Indexed: 11/08/2022] Open
Abstract
Cannabinoid CB1 receptors (CB1Rs) have been shown to be a promising target in medication development for the treatment of addiction. However, clinical trials with SR141716A (rimonabant, a selective CB1R antagonist/inverse agonist) for the treatment of obesity and smoking cessation failed due to unwanted side effects, such as depression, anxiety, and suicidal tendencies. Recent preclinical studies suggest that the neutral CB1R antagonist AM4113 may retain the therapeutic anti-addictive effects of SR141716A in nicotine self-administration models and possibly has fewer unwanted side effects. However, little is known about whether AM4113 is also effective for other drugs of abuse, such as opioids and psychostimulants, and whether it produces depressive side effects similar to SR141716A in experimental animals. In this study, we demonstrated that systemic administration of AM4113 (3 and 10 mg/kg) dose-dependently inhibited the self-administration of intravenous heroin but not cocaine or methamphetamine, whereas SR141716A (3 and 10 mg/kg) dose-dependently inhibited the self-administration of heroin and methamphetamine but not cocaine. In the electrical brain-stimulation reward (BSR) paradigm, SR141716A (3 and 10 mg/kg) dose-dependently increased the BSR stimulation threshold (i.e., decreased the stimulation reward), but AM4113 had no effect on BSR at the same doses, suggesting that SR141716A may produce aversive effects while AM4113 may not. Together, these findings show that neutral CB1R antagonists such as AM4113 deserve further research as a new class of CB1R-based medications for the treatment of opioid addiction without SR141716A-like aversive effects.
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Iacopetta K, Collins-Praino LE, Buisman-Pijlman FTA, Hutchinson MR. Can neuroimmune mechanisms explain the link between ultraviolet light (UV) exposure and addictive behavior? Brain Behav Immun 2018; 73:125-132. [PMID: 30009997 DOI: 10.1016/j.bbi.2018.07.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 07/03/2018] [Accepted: 07/12/2018] [Indexed: 12/22/2022] Open
Abstract
High ultraviolet (UV) light exposure on the skin acts as a reinforcing stimulus, increasing sun-seeking behavior and even addiction-like sun seeking behavior. However, the physiological mechanisms that underlie this process remain to be defined. Here, we propose a novel hypothesis that neuroimmune signaling, arising from inflammatory responses in UV-damaged skin cells, causes potentiated signaling within the cortico-mesolimbic pathway, leading to increased sun-seeking behaviors. This hypothesized UV-induced, skin-to-brain signaling depends upon cell stress signals, termed alarmins, reaching the circulation, thereby triggering the activation of innate immune receptors, such as toll-like receptors (TLRs). This innate immune response is hypothesized to occur both peripherally and centrally, with the downstream signaling from TLR activation affecting both the endogenous opioid system and the mesolimbic dopamine pathway. As both neurotransmitter systems play a key role in the development of addiction behaviors through their actions at key brain regions, such as the nucleus accumbens (NAc), we hypothesize a novel connection between UV-induced inflammation and the activation of pathways that contribute to the development of addiction. This paper is a review of the existing literature to examine the evidence which suggests that chronic sun tanning resembles a behavioral addiction and proposes a novel pathway by which persistent sun-seeking behavior could affect brain neurochemistry in a manner similar to that of repeated drug use.
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Affiliation(s)
- Krystal Iacopetta
- Adelaide Centre for Neuroscience Research, Adelaide Medical School, University of Adelaide, SA, Australia
| | - Lyndsey E Collins-Praino
- Adelaide Centre for Neuroscience Research, Adelaide Medical School, University of Adelaide, SA, Australia
| | - Femke T A Buisman-Pijlman
- Adelaide Centre for Neuroscience Research, Adelaide Medical School, University of Adelaide, SA, Australia
| | - Mark R Hutchinson
- Adelaide Centre for Neuroscience Research, Adelaide Medical School, University of Adelaide, SA, Australia; Australian Research Council Centre of Excellence for Nanoscale BioPhotonics, University of Adelaide, Adelaide, SA, Australia.
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Vaessen TSJ, de Jong L, Schäfer AT, Damen T, Uittenboogaard A, Krolinski P, Nwosu CV, Pinckaers FME, Rotee ILM, Smeets APW, Ermiş A, Kennedy JL, Nieman DH, Tiwari A, van Os J, Drukker M. The interaction between cannabis use and the Val158Met polymorphism of the COMT gene in psychosis: A transdiagnostic meta - analysis. PLoS One 2018; 13:e0192658. [PMID: 29444152 PMCID: PMC5812637 DOI: 10.1371/journal.pone.0192658] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/26/2018] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Neither environmental nor genetic factors are sufficient to predict the transdiagnostic expression of psychosis. Therefore, analysis of gene-environment interactions may be productive. OBJECTIVE A meta-analysis was performed using papers investigating the interaction between cannabis use and catechol-O-methyl transferase (COMT) polymorphism Val158Met (COMTVal158Met). DATA SOURCES PubMed, Embase, PsychInfo. STUDY ELIGIBILITY CRITERIA All observational studies assessing the interaction between COMTVal158Met and cannabis with any psychosis or psychotic symptoms measure as an outcome. STUDY APPRAISAL AND SYNTHESIS METHODS A meta-analysis was performed using the Meta-analysis of Observational Studies in Epidemiology guidelines and forest plots were generated. Thirteen articles met the selection criteria: 7 clinical studies using a case-only design, 3 clinical studies with a dichotomous outcome, and 3 studies analysing a continuous outcome of psychotic symptoms below the threshold of psychotic disorder. The three study types were analysed separately. Validity of the included studies was assessed using "A Cochrane Risk of Bias Assessment Tool: for Non-Randomized Studies of Interventions". RESULTS For case-only studies, a significant interaction was found between cannabis use and COMTVal158Met, with an OR of 1.45 (95% Confidence Interval = 1.05-2.00; Met/Met as the risk genotype). However, there was no evidence for interaction in either the studies including dichotomous outcomes (B = -0.51, 95% Confidence Interval -1.72, 0.70) or the studies including continuous outcomes (B = -0.04 95% Confidence Interval -0.16-0.08). LIMITATION A substantial part of the included studies used the case-only design, which has lower validity and tends to overestimate true effects. CONCLUSION The interaction term between cannabis use and COMTVal158Met was only statistically significant in the case-only studies, but not in studies using other clinical or non-clinical psychosis outcomes. Future additional high quality studies might change current perspectives, yet currently evidence for the interaction remains unconvincing.
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Affiliation(s)
| | - Lea de Jong
- Student Faculty of Health Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Annika Theresia Schäfer
- Student Faculty of Health Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Thomas Damen
- Student Faculty of Health Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Aniek Uittenboogaard
- Student Faculty of Health Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Pauline Krolinski
- Student Faculty of Health Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Chinyere Vicky Nwosu
- Student Faculty of Health Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | | | - Iris Leah Marije Rotee
- Student Faculty of Health Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | | | - Ayşegül Ermiş
- Department of Psychiatry, Bakirkoy Mazhar Osman Mental Health and Neurological Diseases Education and Research Hospital, Istanbul, Turkey
| | - James L. Kennedy
- Neurogenetics Section, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Dorien H. Nieman
- Department of Psychiatry, Academic Medical Center, Amsterdam, the Netherlands
| | - Arun Tiwari
- Neurogenetics Section, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Jim van Os
- Department of Psychiatry and Psychology, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, The Netherlands
- Department Psychiatry, Brain Centre Rudolf Magnus, Utrecht University Medical Centre, Utrecht, The Netherlands
- King's College London, King's Health Partners Department of Psychosis Studies; Institute of Psychiatry, London, United Kingdom
| | - Marjan Drukker
- Department of Psychiatry and Psychology, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, The Netherlands
- * E-mail:
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Leone S, Recinella L, Chiavaroli A, Martinotti S, Ferrante C, Mollica A, Macedonio G, Stefanucci A, Dvorácskó S, Tömböly C, De Petrocellis L, Vacca M, Brunetti L, Orlando G. Emotional disorders induced by Hemopressin and RVD-hemopressin(α) administration in rats. Pharmacol Rep 2017; 69:1247-1253. [DOI: 10.1016/j.pharep.2017.06.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 06/12/2017] [Accepted: 06/21/2017] [Indexed: 02/03/2023]
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Piazza PV, Cota D, Marsicano G. The CB1 Receptor as the Cornerstone of Exostasis. Neuron 2017; 93:1252-1274. [PMID: 28334603 DOI: 10.1016/j.neuron.2017.02.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 01/30/2017] [Accepted: 01/31/2017] [Indexed: 01/07/2023]
Abstract
The type-1 cannabinoid receptor (CB1) is the main effector of the endocannabinoid system (ECS), which is involved in most brain and body functions. In this Perspective, we provide evidence indicating that CB1 receptor functions are key determinants of bodily coordinated exostatic processes. First, we will introduce the concepts of endostasis and exostasis as compensation or accumulation for immediate or future energy needs and discuss how exostasis has been necessary for the survival of species during evolution. Then, we will argue how different specific biological functions of the CB1 receptor in the body converge to provide physiological exostatic processes. Finally, we will introduce the concept of proactive evolution-induced diseases (PEIDs), which helps explain the seeming paradox that an evolutionary-selected physiological function can become the cause of epidemic pathological conditions, such as obesity. We propose here a possible unifying theory of CB1 receptor functions that can be tested by future experimental studies.
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Affiliation(s)
- Pier Vincenzo Piazza
- INSERM, NeuroCentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33077 Bordeaux, France; University of Bordeaux, NeuroCentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33077 Bordeaux, France.
| | - Daniela Cota
- INSERM, NeuroCentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33077 Bordeaux, France; University of Bordeaux, NeuroCentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33077 Bordeaux, France
| | - Giovanni Marsicano
- INSERM, NeuroCentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33077 Bordeaux, France; University of Bordeaux, NeuroCentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33077 Bordeaux, France.
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Geresu B. Khat (Catha edulis F.) and cannabinoids: Parallel and contrasting behavioral effects in preclinical and clinical studies. Pharmacol Biochem Behav 2016; 138:164-73. [PMID: 26469212 DOI: 10.1016/j.pbb.2015.09.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 09/17/2015] [Accepted: 09/27/2015] [Indexed: 11/19/2022]
Abstract
After a brief outline of Catha edulis F. (khat) and the cannabinoid systems, the interactions between the pharmacological effects of khat and cannabinoids will be reviewed. Khat chewing is a widespread habit that has a deep-rooted sociocultural tradition in Africa and the Middle East. Experimental studies conducted to investigate khat's central and peripheral effects have revealed an amphetamine-like mechanism of action mediated through the dopaminergic system. The endocannabinoid system comprises the receptors, the endogenous agonists and the related biochemical machinery responsible for synthesizing these substances and terminating their actions. Endocannabinoids are synthesized "on demand" from membrane phospholipids and then rapidly cleared by cellular uptake and enzymatic degradation. Khat and cannabinoids produce a body of parallel and contrasting behavioral effects. Concurrent consumption of khat and cannabinoids may increase the risk of getting or precipitating psychosis, has rewarding and motivational effect, increases the threshold of pain perception and impairs learning and memory. On the other hand, the action of cannabis to enhance food intake is likely to reduce khat's appetite suppressant effects.
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Affiliation(s)
- Berhanu Geresu
- Department of Pharmacology and Clinical Pharmacy, School of Pharmacy, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
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Preclinical studies on the reinforcing effects of cannabinoids. A tribute to the scientific research of Dr. Steve Goldberg. Psychopharmacology (Berl) 2016; 233:1845-66. [PMID: 27026633 PMCID: PMC5073892 DOI: 10.1007/s00213-016-4244-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 02/09/2016] [Indexed: 11/27/2022]
Abstract
RATIONALE The reinforcing effects of most abused drugs have been consistently demonstrated and studied in animal models, although those of marijuana were not, until the demonstration 15 years ago that delta-9-tetrahydrocannabinol (THC) could serve as a reinforcer in self-administration (SA) procedures in squirrel monkeys. Until then, those effects were inferred using indirect assessments. OBJECTIVES The aim of this manuscript is to review the primary preclinical procedures used to indirectly and directly infer reinforcing effects of cannabinoid drugs. METHODS Results will be reviewed from studies of cannabinoid discrimination, intracranial self-stimulation (ICSS), conditioned place preference (CPP), as well as change in levels of dopamine assessed in brain areas related to reinforcement, and finally from self-administration procedures. For each procedure, an evaluation will be made of the predictive validity in detecting the potential abuse liability of cannabinoids based on seminal papers, with the addition of selected reports from more recent years especially those from Dr. Goldberg's research group. RESULTS AND CONCLUSIONS ICSS and CPP do not provide consistent results for the assessment of potential for abuse of cannabinoids. However, drug discrimination and neurochemistry procedures appear to detect potential for abuse of cannabinoids, as well as several novel "designer cannabinoid drugs." Though after 15 years transfer of the self-administration model of marijuana abuse from squirrel monkeys to other species remains somewhat problematic, studies with the former species have substantially advanced the field, and several reports have been published with consistent self-administration of cannabinoid agonists in rodents.
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12
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Hernandez G, Cheer JF. To Act or Not to Act: Endocannabinoid/Dopamine Interactions in Decision-Making. Front Behav Neurosci 2015; 9:336. [PMID: 26733830 PMCID: PMC4681836 DOI: 10.3389/fnbeh.2015.00336] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 11/19/2015] [Indexed: 12/11/2022] Open
Abstract
Decision-making is an ethologically adaptive construct that is impaired in multiple psychiatric disorders. Activity within the mesocorticolimbic dopamine system has been traditionally associated with decision-making. The endocannabinoid system through its actions on inhibitory and excitatory synapses modulates dopamine activity and decision-making. The aim of this brief review is to present a synopsis of available data obtained when the endocannabinoid system is manipulated and dopamine activity recorded. To this end, we review research using different behavioral paradigms to provide further insight into how this ubiquitous signaling system biases dopamine-related behaviors to regulate decision-making.
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Affiliation(s)
- Giovanni Hernandez
- Faculté de Pharmacie, Université de Montréal Montréal, Quebec, QC, Canada
| | - Joseph F Cheer
- Department of Anatomy and Neurobiology, University of Maryland School of MedicineBaltimore, Maryland, MD, USA; Department of Psychiatry, University of Maryland School of MedicineBaltimore, Maryland, MD, USA
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Flax SM, Wakeford AGP, Cheng K, Rice KC, Riley AL. Effect of norbinaltorphimine on ∆⁹-tetrahydrocannabinol (THC)-induced taste avoidance in adolescent and adult Sprague-Dawley rats. Psychopharmacology (Berl) 2015; 232:3193-201. [PMID: 26025420 PMCID: PMC5551397 DOI: 10.1007/s00213-015-3970-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 05/13/2015] [Indexed: 01/06/2023]
Abstract
RATIONALE The aversive effects of ∆(9)-tetrahydrocannabinol (THC) are mediated by activity at the kappa opioid receptor (KOR) as assessed in adult animals; however, no studies have assessed KOR involvement in the aversive effects of THC in adolescents. Given that adolescents have been reported to be insensitive to the aversive effects induced by KOR agonists, a different mechanism might mediate the aversive effects of THC in this age group. OBJECTIVES The present study was designed to assess the impact of KOR antagonism on the aversive effects of THC in adolescent and adult rats using the conditioned taste avoidance (CTA) procedure. METHODS Following a single pretreatment injection of norbinaltorphimine (norBNI; 15 mg/kg), CTAs induced by THC (0, 0.56, 1.0, 1.8, and 3.2 mg/kg) were assessed in adolescent (n = 84) and adult (n = 83) Sprague-Dawley rats. RESULTS The KOR antagonist, norBNI, had weak and inconsistent effects on THC-induced taste avoidance in adolescent rats in that norBNI both attenuated and strengthened taste avoidance dependent on dose and trial. norBNI had limited impact on the final one-bottle avoidance and no effects on the two-bottle preference test. Interestingly, norBNI had no effect on THC-induced taste avoidance in adult rats as well. CONCLUSIONS That norBNI had no significant effect on THC-induced avoidance in adults, and a minor and inconsistent effect in adolescents demonstrates that the aversive effects of THC are not mediated by KOR activity as assessed by the CTA design in Sprague-Dawley rats.
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Affiliation(s)
- Shaun M Flax
- Pscyhopharmacology Laboratory, Department of Psychology, American University, 4400 Massachusetts Avenue NW, Washington, DC, 20016, USA,
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Rabin RA, George TP. A review of co‐morbid tobacco and cannabis use disorders: Possible mechanisms to explain high rates of co‐use. Am J Addict 2015; 24:105-116. [DOI: 10.1111/ajad.12186] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 10/16/2014] [Accepted: 11/16/2014] [Indexed: 01/29/2023] Open
Affiliation(s)
- Rachel Allison Rabin
- Institute of Medical Science (IMS)Faculty of MedicineUniversity of TorontoTorontoOntarioCanada
- Schizophrenia DivisionCentre for Addiction and Mental Health (CAMH)TorontoOntarioCanada
| | - Tony Peter George
- Institute of Medical Science (IMS)Faculty of MedicineUniversity of TorontoTorontoOntarioCanada
- Schizophrenia DivisionCentre for Addiction and Mental Health (CAMH)TorontoOntarioCanada
- Division of Brain and TherapeuticsDepartment of PsychiatryUniversity of TorontoTorontoOntarioCanada
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15
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Moreira FA, Jupp B, Belin D, Dalley JW. Endocannabinoids and striatal function: implications for addiction-related behaviours. Behav Pharmacol 2015; 26:59-72. [PMID: 25369747 PMCID: PMC5398317 DOI: 10.1097/fbp.0000000000000109] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 09/26/2014] [Indexed: 12/24/2022]
Abstract
Since the identification and cloning of the major cannabinoid receptor expressed in the brain almost 25 years ago research has highlighted the potential of drugs that target the endocannabinoid system for treating addiction. The endocannabinoids, anandamide and 2-arachidonoyl glycerol, are lipid-derived metabolites found in abundance in the basal ganglia and other brain areas innervated by the mesocorticolimbic dopamine systems. Cannabinoid CB1 receptor antagonists/inverse agonists reduce reinstatement of responding for cocaine, alcohol and opiates in rodents. However, compounds acting on the endocannabinoid system may have broader application in treating drug addiction by ameliorating associated traits and symptoms such as impulsivity and anxiety that perpetuate drug use and interfere with rehabilitation. As a trait, impulsivity is known to predispose to addiction and facilitate the emergence of addiction to stimulant drugs. In contrast, anxiety and elevated stress responses accompany extended drug use and may underlie the persistence of drug intake in dependent individuals. In this article we integrate and discuss recent findings in rodents showing selective pharmacological modulation of impulsivity and anxiety by cannabinoid agents. We highlight the potential of selective inhibitors of endocannabinoid metabolism, directed at fatty acid amide hydrolase and monoacylglycerol lipase, to reduce anxiety and stress responses, and discuss novel mechanisms underlying the modulation of the endocannabinoid system, including the attenuation of impulsivity, anxiety, and drug reward by selective CB2 receptor agonists.
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Affiliation(s)
- Fabricio A. Moreira
- Department of Pharmacology, Institute of Biological Science, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
- Departments of Psychology
| | | | | | - Jeffrey W. Dalley
- Departments of Psychology
- Department of Psychiatry, Addenbrookes’s Hospital University of Cambridge, Cambridge, UK
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16
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Wyrofsky R, McGonigle P, Van Bockstaele EJ. Drug discovery strategies that focus on the endocannabinoid signaling system in psychiatric disease. Expert Opin Drug Discov 2014; 10:17-36. [PMID: 25488672 DOI: 10.1517/17460441.2014.966680] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
INTRODUCTION The endocannabinoid (eCB) system plays an important role in the control of mood, and its dysregulation has been implicated in several psychiatric disorders. Targeting the eCB system appears to represent an attractive and novel approach to the treatment of depression and other mood disorders. However, several failed clinical trials have diminished enthusiasm for the continued development of eCB-targeted therapeutics for psychiatric disorders, despite the encouraging preclinical data and promising preliminary results obtained with the synthetic cannabinoid nabilone for treating post-traumatic stress disorder. AREAS COVERED This review describes the eCB system's role in modulating cell signaling within the brain. There is a specific focus on eCB's regulation of monoamine neurotransmission and the stress axis, as well as how dysfunction of this interaction can contribute to the development of psychiatric disorders. Additionally, the review provides discussion on compounds and drugs that target this system and might prove to be successful for the treatment of mood-related psychiatric disorders. EXPERT OPINION The discovery of increasingly selective modulators of CB receptors should enable the identification of optimal therapeutic strategies. It should also maximize the likelihood of developing safe and effective treatments for debilitating psychiatric disorders.
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Affiliation(s)
- Ryan Wyrofsky
- Drexel University, Department of Pharmacology and Physiology , Mail Stop 400, New College Building, 245 N. 15th Street, Philadelphia, PA 19102 , USA
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17
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Bhattacharyya S, Iyegbe C, Atakan Z, Martin-Santos R, Crippa JA, Xu X, Williams S, Brammer M, Rubia K, Prata D, Collier DA, McGuire PK. Protein kinase B (AKT1) genotype mediates sensitivity to cannabis-induced impairments in psychomotor control. Psychol Med 2014; 44:3315-3328. [PMID: 25065544 DOI: 10.1017/s0033291714000920] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND What determines inter-individual variability to impairments in behavioural control that may underlie road-traffic accidents, and impulsive and violent behaviours occurring under the influence of cannabis, the most widely used illicit drug worldwide? METHOD Employing a double-blind, repeated-measures design, we investigated the genetic and neural basis of variable sensitivity to cannabis-induced behavioural dyscontrol in healthy occasional cannabis users. Acute oral challenge with placebo or Δ9-tetrahydrocannabinol (THC), the main psychoactive ingredient in cannabis, was combined with functional magnetic resonance imaging, while participants performed a response inhibition task that involved inhibiting a pre-potent motor response. They were genotyped for rs1130233 single nucleotide polymorphisms (SNPs) of the protein kinase B (AKT1) gene. RESULTS Errors of inhibition were significantly (p = 0.008) increased following administration of THC in carriers of the A allele, but not in G allele homozygotes of the AKT1 rs1130233 SNP. The A allele carriers also displayed attenuation of left inferior frontal response with THC evident in the sample as a whole, while there was a modest enhancement of inferior frontal activation in the G homozygotes. There was a direct relationship (r = -0.327, p = 0.045) between the behavioural effect of THC and its physiological effect in the inferior frontal gyrus, where AKT1 genotype modulated the effect of THC. CONCLUSIONS These results require independent replication and show that differing vulnerability to acute psychomotor impairments induced by cannabis depends on variation in a gene that influences dopamine function, and is mediated through modulation of the effect of cannabis on the inferior frontal cortex, that is rich in dopaminergic innervation and critical for psychomotor control.
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Affiliation(s)
- S Bhattacharyya
- Department of Psychosis Studies,King's College London,Institute of Psychiatry, De Crespigny Park, London,UK
| | - C Iyegbe
- Social, Genetic and Developmental Psychiatry Centre,King's College London,Institute of Psychiatry, De Crespigny Park, London,UK
| | - Z Atakan
- Department of Psychosis Studies,King's College London,Institute of Psychiatry, De Crespigny Park, London,UK
| | - R Martin-Santos
- Pharmacology Research Unit, IMIM-Hospital del Mar and Psychiatric Department,ICN,Hospital Clinico, Barcelona,Spain
| | - J A Crippa
- Department of Neurology, Psychiatry and Medical Psychology, Faculty of Medicine of Ribeirão Preto,University of São Paulo,Brazil
| | - X Xu
- Social, Genetic and Developmental Psychiatry Centre,King's College London,Institute of Psychiatry, De Crespigny Park, London,UK
| | - S Williams
- Department of Neuroimaging, Centre for Neuroimaging Sciences,King's College London,Institute of Psychiatry, De Crespigny Park, London,UK
| | - M Brammer
- Department of Neuroimaging, Centre for Neuroimaging Sciences,King's College London,Institute of Psychiatry, De Crespigny Park, London,UK
| | - K Rubia
- Department of Child and Adolescent Psychiatry,King's College London,Institute of Psychiatry, De Crespigny Park, London,UK
| | - D Prata
- Department of Psychosis Studies,King's College London,Institute of Psychiatry, De Crespigny Park, London,UK
| | - D A Collier
- Social, Genetic and Developmental Psychiatry Centre,King's College London,Institute of Psychiatry, De Crespigny Park, London,UK
| | - P K McGuire
- Department of Psychosis Studies,King's College London,Institute of Psychiatry, De Crespigny Park, London,UK
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Dandash O, Fornito A, Lee J, Keefe RSE, Chee MWL, Adcock RA, Pantelis C, Wood SJ, Harrison BJ. Altered striatal functional connectivity in subjects with an at-risk mental state for psychosis. Schizophr Bull 2014; 40:904-13. [PMID: 23861539 PMCID: PMC4059431 DOI: 10.1093/schbul/sbt093] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Recent functional imaging work in individuals experiencing an at-risk mental state (ARMS) for psychosis has implicated dorsal striatal abnormalities in the emergence of psychotic symptoms, contrasting with earlier findings implicating the ventral striatum. Our aims here were to characterize putative dorsal and ventral striatal circuit-level abnormalities in ARMS individuals using resting-state functional magnetic resonance imaging (fMRI) and to investigate their relationship to positive psychotic symptoms. Resting-state fMRI was acquired in 74 ARMS subjects and 35 matched healthy controls. An established method for mapping ventral and dorsal striatal functional connectivity was used to examine corticostriatal functional integrity. Positive psychotic symptoms were assessed using the Comprehensive Assessment of At-Risk Mental State and the Positive and Negative Syndrome Scale. Compared with healthy controls, ARMS subjects showed reductions in functional connectivity between the dorsal caudate and right dorsolateral prefrontal cortex, left rostral medial prefrontal cortex, and thalamus, and between the dorsal putamen and left thalamic and lenticular nuclei. ARMS subjects also showed increased functional connectivity between the ventral putamen and the insula, frontal operculum, and superior temporal gyrus bilaterally. No differences in ventral striatal (ie, nucleus accumbens) functional connectivity were found. Altered functional connectivity in corticostriatal circuits were significantly correlated with positive psychotic symptoms. Together, these results suggest that risk for psychosis is mediated by a complex interplay of alterations in both dorsal and ventral corticostriatal systems.
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Affiliation(s)
- Orwa Dandash
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne, Melbourne, Australia
| | | | - Jimmy Lee
- Department of General Psychiatry 1 and Research Division, Institute of Mental Health, Buangkok, Singapore;,Office of Clinical Sciences, Graduate Medical School, Duke-National University of Singapore, Singapore, Singapore
| | - Richard S. E. Keefe
- Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC;,Neuroscience and Behavioral Disorders Program, Graduate Medical School, Duke-National University of Singapore, Singapore, Singapore
| | - Michael W. L. Chee
- Neuroscience and Behavioral Disorders Program, Graduate Medical School, Duke-National University of Singapore, Singapore, Singapore
| | - R. Alison Adcock
- Department of Psychiatry and Behavioral Sciences and Center for Cognitive Neuroscience, Duke University, Durham, NC
| | - Christos Pantelis
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne, Melbourne, Australia;,Melbourne Health, Melbourne, Australia
| | - Stephen J. Wood
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne, Melbourne, Australia;,School of Psychology, University of Birmingham, Edgbaston, Birmingham, UK,*To whom correspondence should be addressed; School of Psychology, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK; tel: 44 121 414 4917, fax: 44 121 414 4897, e-mail:
| | - Ben J. Harrison
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne, Melbourne, Australia
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19
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The microinjection of a cannabinoid agonist into the accumbens shell induces anxiogenesis in the elevated plus-maze. Pharmacol Biochem Behav 2014; 124:160-6. [PMID: 24887448 DOI: 10.1016/j.pbb.2014.05.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 05/19/2014] [Accepted: 05/22/2014] [Indexed: 11/23/2022]
Abstract
This study investigated the effect of a cannabinoid agonist injected into the shell region of the nucleus accumbens (nAcb shell) on anxiety-related behaviors. The animals (male Wistar rats) were unilaterally microinjected with either ACEA (arachidonyl-2'-chloroethylamide a CB1 receptor agonist) at doses of 0.005, 0.05 or 0.5 pmol, or vehicle (ethanol 0.04% in saline 0.9%) and submitted to the elevated plus-maze (EPM), a pre-clinical test of anxiety. The data showed that rats microinjected with ACEA (0.05 pmol/0.2 μl) into the nAcb shell exhibited decreased % open arm time and open arm entries in comparison with the control group, which is compatible with an anxiogenic-like effect. To rule out the hypothesis that spread of the drug into the ventricle was responsible for the observed anxiogenic effect, 0.05 pmol ACEA was injected into the lateral ventricle and shown not to alter the responses representative of fear/anxiety and locomotion. The locomotor activity was not changed at the dose of 0.05 pmol ACEA microinjected into the nAcb shell. The present data suggest that activation of cannabinoid receptors in the nAcb shell may modulate fear/anxiety in the EPM.
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20
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Schubart CD, Sommer IEC, Fusar-Poli P, de Witte L, Kahn RS, Boks MPM. Cannabidiol as a potential treatment for psychosis. Eur Neuropsychopharmacol 2014; 24:51-64. [PMID: 24309088 DOI: 10.1016/j.euroneuro.2013.11.002] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 11/05/2013] [Accepted: 11/09/2013] [Indexed: 12/18/2022]
Abstract
Although cannabis use is associated with an increased risk of developing psychosis, the cannabis constituent cannabidiol (CBD) may have antipsychotic properties. This review concisely describes the role of the endocannabinoid system in the development of psychosis and provides an overview of currently available animal, human experimental, imaging, epidemiological and clinical studies that investigated the antipsychotic properties of CBD. In this targeted literature review we performed a search for English articles using Medline and EMBASE. Studies were selected if they described experiments with psychosis models, psychotic symptoms or psychotic disorders as outcome measure and involved the use of CBD as intervention. Evidence from several research domains suggests that CBD shows potential for antipsychotic treatment.
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Affiliation(s)
- C D Schubart
- Tergooi Hospital, Department of Psychiatry, Blaricum, The Netherlands
| | - I E C Sommer
- Brain Center Rudolf Magnus, University Medical Centre Utrecht, Department of Psychiatry, The Netherlands
| | - P Fusar-Poli
- Department of Psychosis Studies, Institute of Psychiatry, King's College London, UK
| | - L de Witte
- Brain Center Rudolf Magnus, University Medical Centre Utrecht, Department of Psychiatry, The Netherlands
| | - R S Kahn
- Tergooi Hospital, Department of Psychiatry, Blaricum, The Netherlands
| | - M P M Boks
- Brain Center Rudolf Magnus, University Medical Centre Utrecht, Department of Psychiatry, The Netherlands.
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21
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Radhakrishnan R, Wilkinson ST, D'Souza DC. Gone to Pot - A Review of the Association between Cannabis and Psychosis. Front Psychiatry 2014; 5:54. [PMID: 24904437 PMCID: PMC4033190 DOI: 10.3389/fpsyt.2014.00054] [Citation(s) in RCA: 165] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 05/02/2014] [Indexed: 01/01/2023] Open
Abstract
Cannabis is the most commonly used illicit drug worldwide, with ~5 million daily users worldwide. Emerging evidence supports a number of associations between cannabis and psychosis/psychotic disorders, including schizophrenia. These associations-based on case-studies, surveys, epidemiological studies, and experimental studies indicate that cannabinoids can produce acute, transient effects; acute, persistent effects; and delayed, persistent effects that recapitulate the psychopathology and psychophysiology seen in schizophrenia. Acute exposure to both cannabis and synthetic cannabinoids (Spice/K2) can produce a full range of transient psychotomimetic symptoms, cognitive deficits, and psychophysiological abnormalities that bear a striking resemblance to symptoms of schizophrenia. In individuals with an established psychotic disorder, cannabinoids can exacerbate symptoms, trigger relapse, and have negative consequences on the course of the illness. Several factors appear to moderate these associations, including family history, genetic factors, history of childhood abuse, and the age at onset of cannabis use. Exposure to cannabinoids in adolescence confers a higher risk for psychosis outcomes in later life and the risk is dose-related. Individuals with polymorphisms of COMT and AKT1 genes may be at increased risk for psychotic disorders in association with cannabinoids, as are individuals with a family history of psychotic disorders or a history of childhood trauma. The relationship between cannabis and schizophrenia fulfills many but not all of the standard criteria for causality, including temporality, biological gradient, biological plausibility, experimental evidence, consistency, and coherence. At the present time, the evidence indicates that cannabis may be a component cause in the emergence of psychosis, and this warrants serious consideration from the point of view of public health policy.
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Affiliation(s)
- Rajiv Radhakrishnan
- Department of Psychiatry, Yale University School of Medicine , New Haven, CT , USA
| | - Samuel T Wilkinson
- Department of Psychiatry, Yale University School of Medicine , New Haven, CT , USA
| | - Deepak Cyril D'Souza
- Department of Psychiatry, Yale University School of Medicine , New Haven, CT , USA ; Abraham Ribicoff Research Facilities, Connecticut Mental Health Center , New Haven, CT , USA ; Schizophrenia and Neuropharmacology Research Group, VA Connecticut Healthcare System , West Haven, CT , USA
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22
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Fitzgerald ML, Chan J, Mackie K, Lupica CR, Pickel VM. Altered dendritic distribution of dopamine D2 receptors and reduction in mitochondrial number in parvalbumin-containing interneurons in the medial prefrontal cortex of cannabinoid-1 (CB1) receptor knockout mice. J Comp Neurol 2013; 520:4013-31. [PMID: 22592925 DOI: 10.1002/cne.23141] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The prelimbic prefrontal cortex (PL) is a brain region integral to complex behaviors that are highly influenced by cannabinoids and by dopamine D2 receptor (D2R)-mediated regulation of fast-firing parvalbumin-containing interneurons. We have recently shown that constitutive deletion of the cannabinoid-1 receptor (CB1R) greatly reduces parvalbumin levels in these neurons. The effects of CB1R deletion on PL parvalbumin interneurons may be ascribed to loss of CB1R-mediated retrograde signaling on mesocortical dopamine transmission, and, in turn, altered expression and/or subcellular distribution of D2R in the PL. Furthermore, diminished parvalbumin expression could indicate metabolic changes in fast-firing interneurons that may be reflected in changes in mitochondrial density in this population. We therefore comparatively examined electron microscopic dual labeling of D2R and parvalbumin in CB1 (-/-) and CB1 (+/+) mice to test the hypothesis that absence of CB1R produces changes in D2R localization and mitochondrial distribution in parvalbumin-containing interneurons of the PL. CB1 (-/-) mice had a significantly lower density of cytoplasmic D2R-immunogold particles in medium parvalbumin-labeled dendrites and a concomitant increase in the density of these particles in small dendrites. These dendrites received both excitatory and inhibitory-type synapses from unlabeled terminals and contained many mitochondria, whose numbers were significantly reduced in CB1 (-/-) mice. Non-parvalbumin dendrites showed no between-group differences in either D2R distribution or mitochondrial number. These results suggest that cannabinoid signaling provides an important determinant of dendritic D2 receptor distribution and mitochondrial availability in fast-spiking interneurons.
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Affiliation(s)
- Megan L Fitzgerald
- Division of Neurobiology, Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, New York 10065, USA
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23
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The cannabinoid CB1 receptor biphasically modulates motor activity and regulates dopamine and glutamate release region dependently. Int J Neuropsychopharmacol 2013; 16:393-403. [PMID: 22391102 DOI: 10.1017/s1461145712000156] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Cannabinoid administration modulates both dopaminergic and glutamatergic neurotransmission. The present study examines the effects of high and low dose WIN55,212-2, a CB1 receptor agonist, on extracellular dopamine and glutamate release in vivo via brain microdialysis in the nucleus accumbens (NAc), striatum and prefrontal cortex (PFC) in parallel to its effects on locomotor activity. WIN55,212-2 increased extracellular dopamine in the NAc (1 mg/kg i.p.), striatum (0.1 and 1 mg/kg i.p.) and PFC (1 mg/kg i.p.). Glutamate release was also elevated by WIN55,212-2 in the PFC (1 mg/kg i.p.) whereas in the NAc (0.1 and 1 mg/kg i.p.) and striatum, it was reduced (1 mg/kg i.p.). WIN55,212-2 administration produced hyperlocomotion at the lower dose (0.1 mg/kg i.p.) and hypolocomotion at the higher dose (1 mg/kg i.p.). Co-administration with the CB1 antagonist, SR-141716A (0.03 mg/kg i.p.), prevented the above effects. According to the present results, WIN55,212-2 affected locomotor activity biphasically while exerting converging effects on dopamine activity but diverging effects on glutamate release between cortical and subcortical regions, especially at the higher dose. These findings emphasize the involvement of the CB1 receptor in the simultaneous modulation of dopaminergic and glutamatergic neurotransmission in brain regions involved in reward and locomotion and suggest possible underlying mechanisms of acute cannabinoid exposure and its psychoactive and behavioural manifestations.
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Sewell RA, Schnakenberg A, Elander J, Radhakrishnan R, Williams A, Skosnik PD, Pittman B, Ranganathan M, D’Souza DC. Acute effects of THC on time perception in frequent and infrequent cannabis users. Psychopharmacology (Berl) 2013. [PMID: 23179965 PMCID: PMC3581701 DOI: 10.1007/s00213-012-2915-6] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
RATIONALE Cannabinoids have been shown to alter time perception, but existing literature has several limitations. Few studies have included both time estimation and production tasks, few control for subvocal counting, most had small sample sizes, some did not record subjects' cannabis use, many tested only one dose, and used either oral or inhaled administration of Δ⁹-tetrahydrocannabinol (THC), leading to variable pharmacokinetics, and some used whole-plant cannabis containing cannabinoids other than THC. Our study attempted to address these limitations. OBJECTIVES This study aims to characterize the acute effects of THC and frequent cannabis use on seconds-range time perception. THC was hypothesized to produce transient, dose-related time overestimation and underproduction. Frequent cannabis smokers were hypothesized to show blunted responses to these alterations. METHODS IV THC was administered at doses from 0.015 to 0.05 mg/kg to 44 subjects who participated in several double-blind, randomized, counterbalanced, crossover, placebo-controlled studies. Visual time estimation and production tasks in the seconds range were presented to subjects three times on each test day. RESULTS All doses induced time overestimation and underproduction. Chronic cannabis use had no effect on baseline time perception. While infrequent/nonsmokers showed temporal overestimation at medium and high doses and temporal underproduction at all doses, frequent cannabis users showed no differences. THC effects on time perception were not dose related. CONCLUSIONS A psychoactive dose of THC increases internal clock speed as indicated by time overestimation and underproduction. This effect is not dose related and is blunted in chronic cannabis smokers who did not otherwise have altered baseline time perception.
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Affiliation(s)
- R. Andrew Sewell
- Yale University, School of Medicine, Department of Psychiatry, New Haven, CT, United States,VA Connecticut Healthcare System, West Haven, CT, United States,Clinical Neuroscience Research Unit, New Haven, CT, United States
| | - Ashley Schnakenberg
- Yale University, School of Medicine, Department of Psychiatry, New Haven, CT, United States,VA Connecticut Healthcare System, West Haven, CT, United States,Clinical Neuroscience Research Unit, New Haven, CT, United States
| | - Jacqueline Elander
- Yale University, School of Medicine, Department of Psychiatry, New Haven, CT, United States,VA Connecticut Healthcare System, West Haven, CT, United States,Clinical Neuroscience Research Unit, New Haven, CT, United States
| | - Rajiv Radhakrishnan
- Yale University, School of Medicine, Department of Psychiatry, New Haven, CT, United States,VA Connecticut Healthcare System, West Haven, CT, United States,Clinical Neuroscience Research Unit, New Haven, CT, United States
| | - Ashley Williams
- Yale University, School of Medicine, Department of Psychiatry, New Haven, CT, United States,VA Connecticut Healthcare System, West Haven, CT, United States,Clinical Neuroscience Research Unit, New Haven, CT, United States
| | - Patrick D. Skosnik
- Yale University, School of Medicine, Department of Psychiatry, New Haven, CT, United States,VA Connecticut Healthcare System, West Haven, CT, United States,Clinical Neuroscience Research Unit, New Haven, CT, United States
| | - Brian Pittman
- Yale University, School of Medicine, Department of Psychiatry, New Haven, CT, United States,Clinical Neuroscience Research Unit, New Haven, CT, United States
| | - Mohini Ranganathan
- Yale University, School of Medicine, Department of Psychiatry, New Haven, CT, United States,VA Connecticut Healthcare System, West Haven, CT, United States,Clinical Neuroscience Research Unit, New Haven, CT, United States
| | - D. Cyril D’Souza
- Yale University, School of Medicine, Department of Psychiatry, New Haven, CT, United States,VA Connecticut Healthcare System, West Haven, CT, United States,Clinical Neuroscience Research Unit, New Haven, CT, United States
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25
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Espana RA, Jones SR. Presynaptic dopamine modulation by stimulant self-administration. Front Biosci (Schol Ed) 2013; 5:261-76. [PMID: 23277050 DOI: 10.2741/s371] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The mesolimbic dopamine system is an essential participant in the initiation and modulation of various forms of goal-directed behavior, including drug reinforcement and addiction processes. Dopamine neurotransmission is increased by acute administration of all drugs of abuse, including the stimulants cocaine and amphetamine. Chronic exposure to these drugs via voluntary self-administration provides a model of stimulant abuse that is useful in evaluating potential behavioral and neurochemical adaptations that occur during addiction. This review describes commonly used methodologies to measure dopamine and baseline parameters of presynaptic dopamine regulation, including exocytotic release and reuptake through the dopamine transporter in the nucleus accumbens core, as well as dramatic adaptations in dopamine neurotransmission and drug sensitivity that occur with acute non-contingent and chronic, contingent self-administration of cocaine and amphetamine.
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Affiliation(s)
- Rodrigo A Espana
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
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El Khoury MA, Gorgievski V, Moutsimilli L, Giros B, Tzavara ET. Interactions between the cannabinoid and dopaminergic systems: evidence from animal studies. Prog Neuropsychopharmacol Biol Psychiatry 2012; 38:36-50. [PMID: 22300746 DOI: 10.1016/j.pnpbp.2011.12.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2011] [Revised: 12/18/2011] [Accepted: 12/18/2011] [Indexed: 12/16/2022]
Abstract
There is a prominent role of the cannabinoid system to control basal ganglia function, in respect to reward, psychomotor function and motor control. Cannabinoid dysregulations might have a pathogenetic role in dopamine- and basal ganglia related neuropsychiatric disorders, such as drug addiction, psychosis, Parkinson's disease and Huntington's disease. This review highlights interactions between cannabinoids, and dopamine, to modulate neurotransmitter release and synaptic plasticity in the context of drug addiction, psychosis and cognition. Modulating endocannabinoid function, as a plasticity based therapeutic strategy, in the above pathologies with particular focus on cannabinoid receptor type 1 (CB1 receptor) antagonists/inverse agonists, is discussed. On the basis of the existing literature and of new experimental evidence presented here, CB1 receptor antagonists might be beneficial in disease states associated with hedonic dysregulation, and with cognitive dysfunction in particular in the context of psychosis. It is suggested that this effects might be mediated via a hyperglutamatergic state through metabotropic glutamate activation. Indications for endocannabinoid catabolism inhibitors in psychiatric disorders, that might be CB1 receptor independent and might involve TRPV1 receptors, are also discussed.
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Affiliation(s)
- Marie-Anne El Khoury
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMRS-952, Université Pierre et Marie Curie, 9 quai St Bernard, 75005 Paris, France
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Kleijn J, Wiskerke J, Cremers T, Schoffelmeer A, Westerink B, Pattij T. Effects of amphetamine on dopamine release in the rat nucleus accumbens shell region depend on cannabinoid CB1 receptor activation. Neurochem Int 2012; 60:791-8. [DOI: 10.1016/j.neuint.2012.03.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2011] [Revised: 02/29/2012] [Accepted: 03/01/2012] [Indexed: 10/28/2022]
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Estrada G, Fatjó-Vilas M, Muñoz MJ, Pulido G, Miñano MJ, Toledo E, Illa JM, Martín M, Miralles ML, Miret S, Campanera S, Bernabeu C, Navarro ME, Fañanás L. Cannabis use and age at onset of psychosis: further evidence of interaction with COMT Val158Met polymorphism. Acta Psychiatr Scand 2011; 123:485-92. [PMID: 21231925 DOI: 10.1111/j.1600-0447.2010.01665.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To examine, in a sample of young psychiatric patients, (n = 157, mean age 17.01 years (SD = 3.6)) whether i) age at first cannabis use and age at emergence of psychiatric disorders are related and ii) such a relationship is modulated by the Val158Met polymorphism in the COMT gene. METHOD Cannabis use profiles and COMT Val158Met genotypes were obtained from 80 inpatients with schizophrenia-spectrum disorders and 77 inpatients with other non-psychotic disorders. RESULTS First, age at first cannabis use correlates with age at onset in both schizophrenia-spectrum and other psychiatric disorder groups: those who started using cannabis earlier had an earlier age at onset of psychiatric disorders. Second, the distribution of the Val158Met genotypes was not different either between diagnosis groups or between cannabis users and non-users. Third, an interaction between Val158Met genotypes and cannabis use was observed specifically on age at emergence of psychotic disorders, with Val/Val genotype carriers showing an earlier age at onset than Met carriers. CONCLUSION Our results suggest the importance of brain maturation timing in which exposure to cannabis occurs. The COMT Val158Met genotype seems to modulate the association between cannabis and age at onset of psychotic disorders. These results are consistent with previous studies.
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Affiliation(s)
- G Estrada
- Anthropology Unit, Department of Animal Biology, Faculty of Biology, University of Barcelona, Spain
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Individual differences in the effects of cannabinoids on motor activity, dopaminergic activity and DARPP-32 phosphorylation in distinct regions of the brain. Int J Neuropsychopharmacol 2010; 13:1175-91. [PMID: 19941698 DOI: 10.1017/s1461145709991003] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
This study explored the behavioural, neurochemical and molecular effects of Delta9-tetrahydrocannabinol (Delta9-THC) and WIN55,212-2, in two rat phenotypes, distinguished on the basis of their vertical activity upon exposure to a novel environment, as high responders (HR) and low responders (LR). Motor effects were assessed under habituated vs. non-habituated conditions. Dopaminergic activity and DARPP-32 phosphorylation were measured in the dorsal striatum, nucleus accumbens, prefrontal cortex and amygdala. These cannabinoids influenced motor activity in a biphasic manner, i.e. low doses stimulated, whereas high doses suppressed motor activity. Dopamine (DA) biosynthesis was increased in most brain regions studied following Delta9-THC administration mainly in HR rats, and low-dose WIN55,212-2 increased DA biosynthesis in HR rats only. Both high and low doses of Delta9-THC increased DARPP-32 phosphorylation in most brain regions studied in both phenotypes, an effect that was also observed following high-dose WIN55,212-2 administration only in the striatum. The present results provide further support for a key role of cannabinoids in the regulation of motoric responses and elements of dopaminergic neurotransmission and reveal their complex differential effects in distinct rat phenotypes, as seen with other drugs of abuse.
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Does dopamine mediate the psychosis-inducing effects of cannabis? A review and integration of findings across disciplines. Schizophr Res 2010; 121:107-17. [PMID: 20580531 DOI: 10.1016/j.schres.2010.05.031] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2010] [Revised: 03/22/2010] [Accepted: 05/16/2010] [Indexed: 11/21/2022]
Abstract
General population epidemiological studies have consistently found that cannabis use increases the risk of developing psychotic disorders in a dose-dependent manner. While the epidemiological signal between cannabis and psychosis has gained considerable attention, the biological mechanism whereby cannabis increases risk for psychosis remains poorly understood. Animal research suggests that delta-9-tetrahydrocannabinol (THC, the main psychoactive component of cannabis) increases dopamine levels in several regions of the brain, including striatal and prefrontal areas. Since dopamine is hypothesized to represent a crucial common final pathway between brain biology and actual experience of psychosis, a focus on dopamine may initially be productive in the examination of the psychotomimetic effects of cannabis. Therefore, this review examines the evidence concerning the interactions between THC, endocannabinoids and dopamine in the cortical as well as subcortical regions implicated in psychosis, and considers possible mechanisms whereby cannabis-induced dopamine dysregulation may give rise to delusions and hallucinations. It is concluded that further study of the mechanisms underlying the link between cannabis and psychosis may be conducted productively from the perspective of progressive developmental sensitization, resulting from gene-environment interactions.
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Melis M, Pistis M. Endocannabinoid signaling in midbrain dopamine neurons: more than physiology? Curr Neuropharmacol 2010; 5:268-77. [PMID: 19305743 PMCID: PMC2644494 DOI: 10.2174/157015907782793612] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2006] [Revised: 03/30/2007] [Accepted: 04/03/2007] [Indexed: 11/22/2022] Open
Abstract
Different classes of neurons in the CNS utilize endogenous cannabinoids as retrograde messengers to shape afferent activity in a short- and long-lasting fashion. Transient suppression of excitation and inhibition as well as long-term depression or potentiation in many brain regions require endocannabinoids to be released by the postsynaptic neurons and activate presynaptic CB1 receptors. Memory consolidation and/or extinction and habit forming have been suggested as the potential behavioral consequences of endocannabinoid-mediated synaptic modulation. HOWEVER, ENDOCANNABINOIDS HAVE A DUAL ROLE: beyond a physiological modulation of synaptic functions, they have been demonstrated to participate in the mechanisms of neuronal protection under circumstances involving excessive excitatory drive, glutamate excitotoxicity, hypoxia-ischemia, which are key features of several neurodegenerative disorders. In this framework, the recent discovery that the endocannabinoid 2-arachidonoyl-glycerol is released by midbrain dopaminergic neurons, under both physiological synaptic activity to modulate afferent inputs and pathological conditions such as ischemia, is particularly interesting for the possible implication of these molecules in brain functions and dysfunctions. Since dopamine dysfunctions underlie diverse neuropsychiatric disorders including schizophrenia, psychoses, and drug addiction, the importance of better understanding the correlation between an unbalanced endocannabinoid signal and the dopamine system is even greater. Additionally, we will review the evidence of the involvement of the endocannabinoid system in the pathogenesis of Parkinson's disease, where neuroprotective actions of cannabinoid-acting compounds may prove beneficial.The modulation of the endocannabinoid system by pharmacological agents is a valuable target in protection of dopamine neurons against functional abnormalities as well as against their neurodegeneration.
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Affiliation(s)
- M Melis
- B.B. Brodie Department of Neuroscience and Center of Excellence for the Neurobiology of Addiction, University of Cagliari, Monserrato, 09042, Italy
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Stokes PRA, Egerton A, Watson B, Reid A, Breen G, Lingford-Hughes A, Nutt DJ, Mehta MA. Significant decreases in frontal and temporal [11C]-raclopride binding after THC challenge. Neuroimage 2010; 52:1521-7. [PMID: 20451621 DOI: 10.1016/j.neuroimage.2010.04.274] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Revised: 04/15/2010] [Accepted: 04/30/2010] [Indexed: 11/24/2022] Open
Abstract
Delta9-tetrahydrocannabinol (THC) increases prefrontal cortical dopamine release in animals, but this is yet to be examined in humans. In man, striatal dopamine release can be indexed using [11C]-raclopride positron emission tomography (PET), and recent reports suggest that cortical [11C]-raclopride binding may also be sensitive to dopaminergic challenges. Using an existing dataset we examined whether THC alters [11C]-raclopride binding potential (BP(ND)) in cortical regions. Thirteen healthy volunteers underwent two [11C]-raclopride PET scans following either oral 10 mg THC or placebo. Significant areas of decreased cortical [11C]-raclopride BP(ND) were identified using whole brain voxel-wise analysis and quantified using a region of interest (ROI) ratio analysis. Effect of blood flow on binding was estimated using a simplified reference tissue model analysis. Results were compared to [11C]-raclopride test-retest reliability in the ROIs identified using a separate cohort of volunteers. Voxel-wise analysis identified three significant clusters of decreased [11C]-raclopride BP(ND) after THC in the right middle frontal gyrus, left superior frontal gyrus and left superior temporal gyrus. Decreases in [11C]-raclopride BPND following THC were greater than test-retest variability in these ROIs. R1, an estimate of blood flow, significantly decreased in the left superior frontal gyrus in the THC condition but was unchanged in the other ROIs. Decreased frontal binding significantly correlated to catechol-o-methyl transferase (COMT) val108 status. We have demonstrated for the first time significant decreases in bilateral frontopolar cortical and left superior temporal gyrus [11C]-raclopride binding after THC. The interpretation of these findings in relation to prefrontal dopamine release is discussed.
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Affiliation(s)
- Paul R A Stokes
- MRC Clinical Science Centre, Imperial College, Hammersmith Hospital, London, UK.
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Roser P, Vollenweider FX, Kawohl W. Potential antipsychotic properties of central cannabinoid (CB1) receptor antagonists. World J Biol Psychiatry 2010; 11:208-19. [PMID: 20218784 DOI: 10.3109/15622970801908047] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Delta(9)-Tetrahydrocannabinol (Delta(9)-THC), the principal psychoactive constituent of the Cannabis sativa plant, and other agonists at the central cannabinoid (CB(1)) receptor may induce characteristic psychomotor effects, psychotic reactions and cognitive impairment resembling schizophrenia. These effects of Delta(9)-THC can be reduced in animal and human models of psychopathology by two exogenous cannabinoids, cannabidiol (CBD) and SR141716. CBD is the second most abundant constituent of Cannabis sativa that has weak partial antagonistic properties at the CB(1) receptor. CBD inhibits the reuptake and hydrolysis of anandamide, the most important endogenous CB(1) receptor agonist, and exhibits neuroprotective antioxidant activity. SR141716 is a potent and selective CB(1) receptor antagonist. Since both CBD and SR141716 can reverse many of the biochemical, physiological and behavioural effects of CB(1) receptor agonists, it has been proposed that both CBD and SR141716 have antipsychotic properties. Various experimental studies in animals, healthy human volunteers, and schizophrenic patients support this notion. Moreover, recent studies suggest that cannabinoids such as CBD and SR141716 have a pharmacological profile similar to that of atypical antipsychotic drugs. In this review, both preclinical and clinical studies investigating the potential antipsychotic effects of both CBD and SR141716 are presented together with the possible underlying mechanisms of action.
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Affiliation(s)
- Patrik Roser
- Research Group Clinical and Experimental Psychopathology, Department of General and Social Psychiatry ZH West, Psychiatric University Hospital Zurich, Zurich, Switzerland
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D’Souza DC, Sewell RA, Ranganathan M. Cannabis and psychosis/schizophrenia: human studies. Eur Arch Psychiatry Clin Neurosci 2009; 259:413-31. [PMID: 19609589 PMCID: PMC2864503 DOI: 10.1007/s00406-009-0024-2] [Citation(s) in RCA: 164] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Accepted: 06/05/2009] [Indexed: 01/26/2023]
Abstract
The association between cannabis use and psychosis has long been recognized. Recent advances in knowledge about cannabinoid receptor function have renewed interest in this association. Converging lines of evidence suggest that cannabinoids can produce a full range of transient schizophrenia-like positive, negative, and cognitive symptoms in some healthy individuals. Also clear is that in individuals with an established psychotic disorder, cannabinoids can exacerbate symptoms, trigger relapse, and have negative consequences on the course of the illness. The mechanisms by which cannabinoids produce transient psychotic symptoms, while unclear may involve dopamine, GABA, and glutamate neurotransmission. However, only a very small proportion of the general population exposed to cannabinoids develop a psychotic illness. It is likely that cannabis exposure is a "component cause" that interacts with other factors to "cause" schizophrenia or a psychotic disorder, but is neither necessary nor sufficient to do so alone. Nevertheless, in the absence of known causes of schizophrenia, the role of component causes remains important and warrants further study. Dose, duration of exposure, and the age of first exposure to cannabinoids may be important factors, and genetic factors that interact with cannabinoid exposure to moderate or amplify the risk of a psychotic disorder are beginning to be elucidated. The mechanisms by which exposure to cannabinoids increase the risk for developing a psychotic disorder are unknown. However, novel hypotheses including the role of cannabinoids on neurodevelopmental processes relevant to psychotic disorders are being studied.
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Affiliation(s)
- Deepak Cyril D’Souza
- Schizophrenia Biological Research Center, Psychiatry Service, VA Connecticut Healthcare System, 116A, 950 Campbell Avenue, West Haven, CT 06516, USA, Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, New Haven, CT, USA, Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Richard Andrew Sewell
- Schizophrenia Biological Research Center, Psychiatry Service, VA Connecticut Healthcare System, 116A, 950 Campbell Avenue, West Haven, CT 06516, USA, Substance Abuse Research Program, VA Connecticut Healthcare System, West Haven, CT, USA
| | - Mohini Ranganathan
- Schizophrenia Biological Research Center, Psychiatry Service, VA Connecticut Healthcare System, 116A, 950 Campbell Avenue, West Haven, CT 06516, USA, Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
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Konings M, Henquet C, Maharajh HD, Hutchinson G, Van Os J. Early exposure to cannabis and risk for psychosis in young adolescents in Trinidad. Acta Psychiatr Scand 2008; 118:209-13. [PMID: 18452569 DOI: 10.1111/j.1600-0447.2008.01202.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Cannabis use increases the risk for psychosis, but psychotogenic effects of cannabis may be restricted to exposure during early adolescence. METHOD Four hundred and seventy-two participants (aged 12-23 years), randomly selected from the general population in Trinidad, completed questionnaires on past and current cannabis use and psychotic symptoms (using the Community Assessment of Psychic Experiences). RESULTS Cannabis use increased the risk of experiencing psychotic symptoms and this effect was conditional on early exposure, defined around the mean age of onset of cannabis use. Thus, exposure before but not after the age of 14 years predicted psychotic symptoms (respectively beta: 0.71, 95% CI 0.22; 1.19, P = 0.004 and beta: -0.11, 95% CI -0.57; 0.36, P = 0.66). The developmental effect of cannabis use was independent of use of other drugs or current use of cannabis. CONCLUSION Early adolescence may be a critical period with regard to the psychotogenic effect of cannabis across geographical settings and ethnic groups.
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Affiliation(s)
- M Konings
- Department of Psychiatry, GGZ Eindhoven, Eindhoven, the Netherlands
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36
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Wiley JL, Kendler SH, Burston JJ, Howard DR, Selley DE, Sim-Selley LJ. Antipsychotic-induced alterations in CB1 receptor-mediated G-protein signaling and in vivo pharmacology in rats. Neuropharmacology 2008; 55:1183-90. [PMID: 18708079 DOI: 10.1016/j.neuropharm.2008.07.026] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Revised: 05/20/2008] [Accepted: 07/17/2008] [Indexed: 11/26/2022]
Abstract
Dysregulation of the endocannabinoid and dopamine systems has been implicated in schizophrenia. The purpose of this study was to examine the effects of sub-chronic treatment with two antipsychotics on CB1 receptor-mediated in vitro and in vivo effects. Adult and adolescent male and female rats were injected twice daily with haloperidol (0.3 mg/kg), clozapine (10 mg/kg), or saline for 10 days. Subsequently, CB1 receptor number and function were assessed by [3H]SR141716 and WIN55,212-2-stimulated [35S]GTPgammaS binding, respectively. The effects of sub-chronic antipsychotic treatment on the in vivo actions of Delta9-tetrahydrocannabinol (Delta9-THC) were also evaluated. In adult female rats, antipsychotic treatment attenuated maximal stimulation of CB1 receptor-mediated G-protein activity in the striatum (clozapine) and prefrontal cortex (both antipsychotics), but not in the ventral midbrain. Associated changes in CB1 receptor number were not observed, suggesting that this attenuation was not due to downregulation. In vivo, sub-chronic treatment with clozapine, but not haloperidol, attenuated Delta9-THC-induced suppression of activity in adult females, whereas neither drug altered hypothermia or catalepsy. In contrast, antipsychotic treatment did not change CB1 receptor-mediated G-protein activation in any brain region in adult male rats and in adolescents of either sex. In vivo, haloperidol, but not clozapine, enhanced Delta9-THC-mediated suppression of activity and hypothermia in adult male rats whereas neither antipsychotic affected Delta9-THC-induced in vivo effects in adolescent rats. These findings suggest that modulation of the endocannabinoid system might contribute in a sex- and age-selective manner to differences in motor side effects of clozapine versus haloperidol.
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Affiliation(s)
- Jenny L Wiley
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, P.O. Box 980613, Richmond, VA 23298-0613, USA.
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Effects of haloperidol on the behavioral, subjective, cognitive, motor, and neuroendocrine effects of Delta-9-tetrahydrocannabinol in humans. Psychopharmacology (Berl) 2008; 198:587-603. [PMID: 18228005 PMCID: PMC2878815 DOI: 10.1007/s00213-007-1042-2] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2007] [Accepted: 11/28/2007] [Indexed: 10/22/2022]
Abstract
INTRODUCTION Cannabinoids produce a spectrum of effects in humans including euphoria, cognitive impairments, psychotomimetic effects, and perceptual alterations. The extent to which dopaminergic systems contribute to the effects of Delta-9-tetrahydrocannabinol (Delta-9-THC) remains unclear. This study evaluated whether pretreatment with a dopamine receptor antagonist altered the effects of Delta-9-THC in humans. MATERIALS AND METHODS In a 2-test-day double-blind study, 28 subjects including healthy subjects (n = 17) and frequent users of cannabis (n = 11) were administered active (0.057 mg/kg) or placebo oral haloperidol in random order followed 90 and 215 min later by fixed order intravenous administration of placebo (vehicle) and active (0.0286 mg/kg) Delta-9-THC, respectively. RESULTS Consistent with previous reports, intravenous Delta-9-THC produced psychotomimetic effects, perceptual alterations, and subjective effects including "high." Delta-9-THC also impaired verbal recall and attention. Haloperidol pretreatment did not reduce any of the behavioral effects of Delta-9-THC. Haloperidol worsened the immediate free and delayed free and cued recall deficits produced by Delta-9-THC. Haloperidol and Delta-9-THC worsened distractibility and vigilance. Neither drug impaired performance on a motor screening task, the Stockings of Cambridge task, or the delayed match to sample task. Frequent users had lower baseline plasma prolactin levels and blunted Delta-9-THC induced memory impairments. CONCLUSIONS The deleterious effects of haloperidol pretreatment on the cognitive effects of Delta-9-THC are consistent with the preclinical literature in suggesting crosstalk between DAergic and CBergic systems. However, it is unlikely that DA D(2) receptor mechanisms play a major role in mediating the psychotomimetic and perceptual altering effects of Delta-9-THC. Further investigation is warranted to understand the basis of the psychotomimetic effects of Delta-9-THC and to better understand the crosstalk between DAergic and CBergic systems.
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Cohen M, Solowij N, Carr V. Cannabis, cannabinoids and schizophrenia: integration of the evidence. Aust N Z J Psychiatry 2008; 42:357-68. [PMID: 18473254 DOI: 10.1080/00048670801961156] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Understanding of the neurophysiological basis of cognitive, behavioural and perceptual disturbances associated with long-term cannabis use has grown dramatically. Exogenous cannabinoids alter the normative functioning of the endogenous cannabinoid system. This system is an important regulator of neurotransmission. Recent research has demonstrated abnormalities of the cannabinoid system in schizophrenia. The purpose of the present paper was to selectively review the links between cannabis use and psychosis, drawing upon recent epidemiological, clinical, cognitive, brain imaging and neurobiological research. The aim is to assist clinicians to probe more deeply into the newly unfolding world of cannabinoid physiology and to critically evaluate the potential role of cannabis in the onset and persistence of cognitive impairments and psychosis in otherwise healthy users and in schizophrenia.
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Affiliation(s)
- Martin Cohen
- Centre for Brain and Mental Health Research, University of Newcastle, Hunter New England Mental Health Service, Newcastle, NSW, Australia.
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Fattore L, Fadda P, Spano MS, Pistis M, Fratta W. Neurobiological mechanisms of cannabinoid addiction. Mol Cell Endocrinol 2008; 286:S97-S107. [PMID: 18372102 DOI: 10.1016/j.mce.2008.02.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Revised: 02/12/2008] [Accepted: 02/12/2008] [Indexed: 12/18/2022]
Abstract
The endocannabinoid system is implicated in the regulation of a variety of physiological processes, among which conditioning, motivation, habit forming, memory, learning, and cognition play pivotal roles in drug reinforcement and reward. In this article we will give a synopsis of last developments in research on cannabinoid actions on brain reward circuits coming from behavioral, neurochemical and electrophysiological studies. Central cannabinoid-induced effects as measured by animal models of addiction, in vivo cerebral microdialysis, in vitro and in vivo electrophysiological recording techniques, will be reviewed. Brain sites that have been implicated in the mediation of addictive cannabinoid properties include primarily the ventral tegmental area, the nucleus accumbens, and the medial prefrontal cortex, although the amygdala, the substantia nigra, the globus pallidus, and the hippocampus have also been shown to be critical structures mediating motivational and reinforcing effects of cannabinoids. Putative neurobiological mechanisms underlying these effects will be delineated.
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Affiliation(s)
- L Fattore
- Institute of Neuroscience CNR, National Research Council, Section of Cagliari, Italy
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Juckel G, Roser P, Nadulski T, Stadelmann AM, Gallinat J. Acute effects of Delta9-tetrahydrocannabinol and standardized cannabis extract on the auditory evoked mismatch negativity. Schizophr Res 2007; 97:109-17. [PMID: 17884351 DOI: 10.1016/j.schres.2007.08.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2007] [Revised: 08/12/2007] [Accepted: 08/15/2007] [Indexed: 11/20/2022]
Abstract
Reduced amplitudes of auditory evoked mismatch negativity (MMN) have often been found in schizophrenic patients, indicating deficient auditory information processing and working memory. Cannabis-induced psychotic states may resemble schizophrenia. Currently, there are discussions focusing on the close relationship between cannabis, the endocannabinoid and dopaminergic system, and the onset of schizophrenic psychosis. This study investigated the effects of cannabis on MMN amplitude in 22 healthy volunteers (age 28+/-6 years, 11 male) by comparing Delta(9)-tetrahydrocannabinol (Delta(9)-THC) and standardized cannabis extract containing Delta(9)-THC and cannabidiol (CBD) in a prospective, double-blind, placebo-controlled cross-over design. The MMNs resulting from 1000 auditory stimuli were recorded by 32 channel EEG. The standard stimuli were 1000 Hz, 80 dB SPL, and 100 ms duration. The deviant stimuli differed in frequency (1500 Hz). Significantly greater MMN amplitude values at central electrodes were found under cannabis extract, but not under Delta(9)-THC. There were no significant differences between MMN amplitudes at frontal electrodes. MMN amplitudes at central electrodes were significantly correlated with 11-OH-THC concentration, the most important psychoactive metabolite of Delta(9)-THC. Since the main difference between Delta(9)-THC and standardized cannabis extract is CBD, which seems to have neuroprotective and anti-psychotic properties, it can be speculated whether the greater MMN amplitude that may imply higher cortical activation and cognitive performance is related to the positive effects of CBD. This effect may be relevant for auditory cortex activity in particular because only MMN amplitudes at the central, but not at the frontal electrodes were enhanced under cannabis.
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Affiliation(s)
- Georg Juckel
- Department of Psychiatry, University Hospital Charité, Berlin, Germany.
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Rea K, Roche M, Finn DP. Supraspinal modulation of pain by cannabinoids: the role of GABA and glutamate. Br J Pharmacol 2007; 152:633-48. [PMID: 17828292 PMCID: PMC2190023 DOI: 10.1038/sj.bjp.0707440] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Recent physiological, pharmacological and anatomical studies provide evidence that one of the main roles of the endocannabinoid system in the brain is the regulation of gamma-aminobutyric acid (GABA) and glutamate release. This article aims to review this evidence in the context of its implications for pain. We first provide a brief overview of supraspinal regulation of nociception, followed by a review of the evidence that the brain's endocannabinoid system modulates nociception. We look in detail at regulation of supraspinal GABAergic and glutamatergic neurons by the endocannabinoid system and by exogenously administered cannabinoids. Finally, we review the evidence that cannabinoid-mediated modulation of pain involves modulation of GABAergic and glutamatergic neurotransmission in key brain regions.
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Affiliation(s)
- K Rea
- Department of Pharmacology and Therapeutics, National University of Ireland Galway, Ireland
| | - M Roche
- Department of Pharmacology and Therapeutics, National University of Ireland Galway, Ireland
| | - D P Finn
- Department of Pharmacology and Therapeutics, National University of Ireland Galway, Ireland
- Author for correspondence:
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Varvel SA, Martin BR, Lichtman AH. Lack of behavioral sensitization after repeated exposure to THC in mice and comparison to methamphetamine. Psychopharmacology (Berl) 2007; 193:511-9. [PMID: 17497137 PMCID: PMC2637562 DOI: 10.1007/s00213-007-0811-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2007] [Accepted: 04/19/2007] [Indexed: 10/23/2022]
Abstract
RATIONALE Recent evidence has provided support for the incentive-sensitization model of addiction, where repeated stimulation of neural reward circuits leads to a long-lasting sensitization of mesolimbic dopaminergic activity. This phenomenon has been demonstrated with many drugs of abuse, most often by measuring progressively increased activating effects of drugs on locomotor activity, thought to reflect an underlying neural sensitization. Whether cannabinoids, and in particular Delta(9)-tetrahydrocannabinol (THC), produce similar effects in this model is somewhat controversial, with mixed evidence in the literature. OBJECTIVES These experiments were conducted to determine whether behavioral sensitization could be established in mice after repeated exposure to THC. Sensitization to repeated methamphetamine treatment was used as a positive control. METHODS The effects of acute and repeated intermittent (every 3-4 days) treatment with THC or methamphetamine on locomotor activity were determined in Institute of Cancer Research (ICR) mice. Additional experiments with THC employed a dosing regimen that increased the number of injections, controlled for behavioral tolerance, examined different aspects of behavior, and used a different species (Sprague-Dawley rats). RESULTS Both methamphetamine and THC acutely increased activity. A robust dose-dependent sensitization was observed after intermittent treatment with methamphetamine but not with THC. Additionally, no evidence for behavioral sensitization to the effects of THC was found with any of the various protocols. CONCLUSION These data suggest that repeated THC treatment is less likely to produce behavioral sensitization than are other drugs of abuse. It appears that this phenomenon may only occur under very particular conditions, which raises doubts about its relevance to chronic cannabis users.
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Affiliation(s)
- Stephen A Varvel
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, P.O. Box 980613, Richmond, VA 23298-0613, USA.
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Boydell J, Dean K, Dutta R, Giouroukou E, Fearon P, Murray R. A comparison of symptoms and family history in schizophrenia with and without prior cannabis use: implications for the concept of cannabis psychosis. Schizophr Res 2007; 93:203-10. [PMID: 17462864 DOI: 10.1016/j.schres.2007.03.014] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2006] [Revised: 03/11/2007] [Accepted: 03/17/2007] [Indexed: 11/17/2022]
Abstract
BACKGROUND There is considerable interest in cannabis use in psychosis. It has been suggested that the chronic psychosis associated with cannabis use, is symptomatically distinct from idiopathic schizophrenia. Several studies have reported differences in psychopathology and family history in people with schizophrenia according to whether or not they were cannabis users. We set out to test the hypotheses arising from these studies that cannabis use is associated with more bizarre behaviour, more thought disorder, fewer negative symptoms including blunted affect, more delusions of reference, more paranoid delusions and a stronger family history of schizophrenia. METHOD We used a case register that contained 757 cases of first onset schizophrenia, 182 (24%) of whom had used cannabis in the year prior to first presentation, 552 (73%) had not and 3% had missing data. We completed the OPCRIT checklist on all patients and investigated differences in the proportion of people with distractibility, bizarre behaviour, positive formal thought disorder, delusions of reference, well organised delusions, any first rank symptom, persecutory delusions, abusive/accusatory hallucinations, blunted affect, negative thought disorder, any negative symptoms (catatonia, blunted affect, negative thought disorder, or deterioration), lack of insight, suicidal ideation and a positive family history of schizophrenia, using chi square tests. Logistic regression modelling was then used to determine whether prior cannabis use affected the presence of the characteristics after controlling for age, sex and ethnicity. RESULTS There was no statistically significant effect of cannabis use on the presence of any of the above. There remained however a non-significant trend towards more insight (OR 0.65 p=0.055 for "loss of insight") and a finding of fewer abusive or accusatory hallucinations (OR 0.65 p=0.049) of borderline significance amongst the cannabis users. These were in the hypothesised direction. There was no evidence of fewer negative symptoms or greater family history amongst cannabis users. CONCLUSION We found few appreciable differences in symptomatology between schizophrenic patients who were or were not cannabis users. There were no differences in the proportion of people with a positive family history of schizophrenia between cannabis users and non-users. This argues against a distinct schizophrenia-like psychosis caused by cannabis.
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Affiliation(s)
- J Boydell
- Division of Psychological Medicine, PO Box 63, Institute of Psychiatry, De Crespigny Park, Denmark Hill, London, SE5 8AF, United Kingdom.
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Mátyás F, Urbán GM, Watanabe M, Mackie K, Zimmer A, Freund TF, Katona I. Identification of the sites of 2-arachidonoylglycerol synthesis and action imply retrograde endocannabinoid signaling at both GABAergic and glutamatergic synapses in the ventral tegmental area. Neuropharmacology 2007; 54:95-107. [PMID: 17655884 PMCID: PMC2238033 DOI: 10.1016/j.neuropharm.2007.05.028] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2007] [Revised: 05/22/2007] [Accepted: 05/31/2007] [Indexed: 10/23/2022]
Abstract
Intact endogenous cannabinoid signaling is involved in several aspects of drug addiction. Most importantly, endocannabinoids exert pronounced influence on primary rewarding effects of abused drugs, including exogenous cannabis itself, through the regulation of drug-induced increase in bursting activity of dopaminergic neurons in the ventral tegmental area (VTA). Previous electrophysiological studies have proposed that these dopaminergic neurons may release endocannabinoids in an activity-dependent manner to regulate their various synaptic inputs; however, the underlying molecular and anatomical substrates have so far been elusive. To facilitate understanding of the neurobiological mechanisms involving endocannabinoid signaling in drug addiction, we carried out detailed analysis of the molecular architecture of the endocannabinoid system in the VTA. In situ hybridization for sn-1-diacylglycerol lipase-alpha (DGL-alpha), the biosynthetic enzyme of the most abundant endocannabinoid, 2-arachidonoylglycerol (2-AG), revealed that DGL-alpha was expressed at moderate to high levels by most neurons of the VTA. Immunostaining for DGL-alpha resulted in a widespread punctate pattern at the light microscopic level, whereas high-resolution electron microscopic analysis demonstrated that this pattern is due to accumulation of the enzyme adjacent to postsynaptic specializations of several distinct morphological types of glutamatergic and GABAergic synapses. These axon terminal types carried presynaptic CB(1) cannabinoid receptors on the opposite side of DGL-alpha-containing synapses and double immunostaining confirmed that DGL-alpha is present on the plasma membrane of both tyrosine hydroxylase (TH)-positive (dopaminergic) and TH-negative dendrites. These findings indicate that retrograde synaptic signaling mediated by 2-AG via CB(1) may influence the drug-reward circuitry at multiple types of synapses in the VTA.
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Affiliation(s)
- Ferenc Mátyás
- Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1083 Budapest, Hungary
| | - Gabriella M. Urbán
- Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1083 Budapest, Hungary
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University School of Medicine, Sapporo 060-8638, Japan
| | - Ken Mackie
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, USA
| | - Andreas Zimmer
- Department of Molecular Psychiatry, Life and Brain Center, University of Bonn, 53105 Bonn, Germany
| | - Tamás F. Freund
- Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1083 Budapest, Hungary
| | - István Katona
- Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1083 Budapest, Hungary
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Piazza PV, Lafontan M, Girard J. Integrated physiology and pathophysiology of CB1-mediated effects of the endocannabinoid system. DIABETES & METABOLISM 2007; 33:97-107. [PMID: 17350871 DOI: 10.1016/j.diabet.2007.02.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Accepted: 02/06/2007] [Indexed: 11/18/2022]
Abstract
The discovery of the endocannabinoid system (ECS) has raised a large interest in the scientific community providing us with a strikingly long list of apparently independent multi organ effects. As a result, in most reviews on this issue the main function of the ECS is considered as modulatory. Unfortunately, this vision does not add much to our understanding of the specific biological function of the ECS. Thus, modulatory is what in general all biological systems are or should be. In this review we will show that the apparent inconsistent puzzle of the very different tissue specific effects of endocannabinoids (ECs) can be reconstructed in one unitary picture. This picture clearly shows that all the different CB1-mediated effects of ECs sub-serve one major physiological function: to facilitate and increase energy storage. We will also analyze the implications of this unitary vision of the ECS in different contexts. First, in the context of the systems that regulate energy balance, introducing a new systematization based on two homeostatic systems: an endostatic and an exostatic system. Second, in the context of evolution, showing how the function of the ECS has shifted from essential to survival to almost pathological in current times. Finally, in a pathophysiological context, introducing the new concept of "proactive evolution diseases", which can explain the current obesity epidemic and the role the ECS plays in it.
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Affiliation(s)
- P V Piazza
- INSERM Bordeaux Neuroscience Research Center (U862), University of Bordeaux-II, 146 rue Leo-Saignat, 33077 Bordeaux, France.
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Ranganathan M, D'Souza DC. The acute effects of cannabinoids on memory in humans: a review. Psychopharmacology (Berl) 2006; 188:425-44. [PMID: 17019571 DOI: 10.1007/s00213-006-0508-y] [Citation(s) in RCA: 323] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2006] [Accepted: 06/28/2006] [Indexed: 11/29/2022]
Abstract
RATIONALE Cannabis is one of the most frequently used substances. Cannabis and its constituent cannabinoids are known to impair several aspects of cognitive function, with the most robust effects on short-term episodic and working memory in humans. A large body of the work in this area occurred in the 1970s before the discovery of cannabinoid receptors. Recent advances in the knowledge of cannabinoid receptors' function have rekindled interest in examining effects of exogenous cannabinoids on memory and in understanding the mechanism of these effects. OBJECTIVE The literature about the acute effects of cannabinoids on memory tasks in humans is reviewed. The limitations of the human literature including issues of dose, route of administration, small sample sizes, sample selection, effects of other drug use, tolerance and dependence to cannabinoids, and the timing and sensitivity of psychological tests are discussed. Finally, the human literature is discussed against the backdrop of preclinical findings. RESULTS Acute administration of Delta-9-THC transiently impairs immediate and delayed free recall of information presented after, but not before, drug administration in a dose- and delay-dependent manner. In particular, cannabinoids increase intrusion errors. These effects are more robust with the inhaled and intravenous route and correspond to peak drug levels. CONCLUSIONS This profile of effects suggests that cannabinoids impair all stages of memory including encoding, consolidation, and retrieval. Several mechanisms, including effects on long-term potentiation and long-term depression and the inhibition of neurotransmitter (GABA, glutamate, acetyl choline, dopamine) release, have been implicated in the amnestic effects of cannabinoids. Future research in humans is necessary to characterize the neuroanatomical and neurochemical basis of the memory impairing effects of cannabinoids, to dissect out their effects on the various stages of memory and to bridge the expanding gap between the humans and preclinical literature.
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Affiliation(s)
- Mohini Ranganathan
- Schizophrenia Biological Research Center, VA Connecticut Healthcare System, West-Haven, CT 06516, USA
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Kolb B, Gorny G, Limebeer CL, Parker LA. Chronic treatment with Delta-9-tetrahydrocannabinol alters the structure of neurons in the nucleus accumbens shell and medial prefrontal cortex of rats. Synapse 2006; 60:429-36. [PMID: 16881072 DOI: 10.1002/syn.20313] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The potential of repeated exposure to Delta(9)-tetrahydrocannabinol (Delta(9)-THC) to produce long-lasting changes in synaptic connections in a manner similar to other drugs of abuse was evaluated in Sprague-Dawley rats. For 12 days, rats received two i.p. injections per day (8 h apart) of vehicle, a low dose of Delta(9)-THC (0.5 mg/kg), or escalating doses of Delta(9)-THC (0.5-4.0 mg/kg). Thirty days later, they were evaluated for sensitized locomotor activity (during the night cycle) for 60 min on each of three trials. Using a within-groups design, rats were tested following an injection of vehicle, 0.5 mg/kg Delta(9)-THC or 2.0 mg/kg Delta(9)-THC. The rats showed no evidence of sensitized locomotor activity in any group. Twenty-four hours after the final sensitization test, their brains were removed and then processed for Golgi-Cox staining. Prior exposure to Delta(9)-THC (both the low dose and the escalating doses) increased the length of the dendrites as well as the number of dendritic branches in the shell of the nucleus accumbens and in the medial prefrontal cortex, but not in the hippocampus, striatum, orbital frontal cortex, parietal cortex, or occipital cortex. These results are similar to those evident in brains of rats sensitized to amphetamine, and support previous findings that cannabinoids promote DA activity in the mesolimbic DA system.
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Affiliation(s)
- Bryan Kolb
- Department of Psychology and Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4.
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Beardsley PM, Thomas BF. Current evidence supporting a role of cannabinoid CB1 receptor (CB1R) antagonists as potential pharmacotherapies for drug abuse disorders. Behav Pharmacol 2006; 16:275-96. [PMID: 16148435 DOI: 10.1097/00008877-200509000-00003] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Since the discovery of the cannabinoid CB1 receptor (CB1R) in 1988, and subsequently of the CB2 receptor (CB2R) in 1993, there has been an exponential growth of research investigating the functions of the endocannabinoid system. The roles of CB1Rs have been of particular interest to behavioral pharmacologists because of their selective presence within the central nervous system (CNS) and because of their association with brain-reward circuits involving mesocorticolimbic dopamine systems. One potential role that has become of considerable recent focus is the ability of CB1Rs to modulate the effects of drugs of abuse. Many drugs of abuse elevate dopamine levels, and the ability of CB1R antagonists or inverse agonists to attenuate these elevations has suggested their potential application as pharmacotherapies for treating drug abuse disorders. With the identification of the selective CB1R antagonist, SR141716, in 1994, and its subsequent widespread availability, there has been a rapid expansion of research investigating its ability to modulate the effects of drugs of abuse. The preliminary clinical reports of its success in retarding relapse in tobacco users have accelerated this expansion. This report critically reviews preclinical and clinical studies involving the ability of CB1R antagonists to attenuate the effects of drugs of abuse, while providing an overview of the neuroanatomical and neurochemical points of contact between the endocannabinoid system and systems mediating abuse-related effects.
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Affiliation(s)
- P M Beardsley
- Department of Pharmacology, Virginia Commonwealth University, Richmond, Virginia 23298-0613, USA.
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Egerton A, Allison C, Brett RR, Pratt JA. Cannabinoids and prefrontal cortical function: Insights from preclinical studies. Neurosci Biobehav Rev 2006; 30:680-95. [PMID: 16574226 DOI: 10.1016/j.neubiorev.2005.12.002] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2005] [Revised: 11/18/2005] [Accepted: 12/19/2005] [Indexed: 10/24/2022]
Abstract
Marijuana use has been associated with disordered cognition across several domains influenced by the prefrontal cortex (PFC). Here, we review the contribution of preclinical research to understanding the effects of cannabinoids on cognitive ability, and the mechanisms by which cannabinoids may affect the neurochemical processes in the PFC that are associated with these impairments. In rodents, acute administration of cannabinoid agonists produces deficits in working memory, attentional function and reversal learning. These effects appear to be largely dependent on CB1 cannabinoid receptor activation. Preclinical studies also indicate that the endogenous cannabinoid system may tonically regulate some mnemonic processes. Effects of cannabinoids on cognition may be mediated via interaction with neurochemical processes in the PFC and hippocampus. In the PFC, cannabinoids may alter dopaminergic, cholinergic and serotonergic transmission. These mechanisms may underlie cognitive impairments observed following marijuana intake in humans, and may also be relevant to other disorders of cognition. Preclinical research will further enhance our understanding of the interactions between the cannabinoid system and cognitive functioning.
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Affiliation(s)
- Alice Egerton
- Department of Physiology and Pharmacology, Strathclyde Institute for Biomedical Sciences, University of Strathclyde, Glasgow G4 0NR, UK
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Crippa JA, Lacerda ALT, Amaro E, Busatto Filho G, Zuardi AW, Bressan RA. [Brain effects of cannabis--neuroimaging findings]. BRAZILIAN JOURNAL OF PSYCHIATRY 2005; 27:70-8. [PMID: 15867988 DOI: 10.1590/s1516-44462005000100016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cannabis is the most widely used illicit drug. Despite this, only a small number of studies have investigated the long-term neurotoxic consequences of cannabis use. Structural and functional neuroimaging techniques are powerful research tools to investigate possible cannabis-induced pathophysiological changes. A computer literature review was conducted in the MEDLINE and PsycLIT databases between 1966 and November of 2004 with the search terms 'cannabis', 'marijuana', 'neuroimaging', 'magnetic resonance', 'computed tomography', 'positron emission tomography', 'single photon emission computed tomography", 'SPET', 'MRI' and 'CT'. Structural neuroimaging studies have yielded conflicting results. Most studies report no evidence of cerebral atrophy or regional changes in tissue volumes, and one study suggested that long-term users who started regular use on early adolescence have cerebral atrophy as well as reduction in gray matter. However, several methodological shortcomings limit the interpretation of these results. Functional neuroimaging studies have reported increases in neural activity in regions that may be related with cannabis intoxication or mood-change effects (orbital and mesial frontal lobes, insula, and anterior cingulate) and decreases in activity of regions related with cognitive functions impaired during acute intoxication. The important question whether residual neurotoxic effects occur after prolonged and regular use of cannabis remains unclear, with no study addressing this question directly. Better designed neuroimaging studies, combined with cognitive evaluation, may be elucidative on this issue.
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Affiliation(s)
- José Alexandre Crippa
- Departamento de Neurologia, Psiquiatria e Psicologia Médica, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brazil.
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