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Martínez-Rivera A, Fetcho RN, Birmingham L, Jiu JX, Yang R, Foord C, Scala-Chávez D, Mekawy N, Pleil K, Pickel VM, Liston C, Castorena CM, Levitz J, Pan YX, Briand LA, Rajadhyaksha AM, Lee FS. Elevating levels of the endocannabinoid 2-arachidonoylglycerol blunts opioid reward but not analgesia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.02.585967. [PMID: 38766079 PMCID: PMC11101127 DOI: 10.1101/2024.04.02.585967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Converging findings have established that the endocannabinoid (eCB) system serves as a possible target for the development of new treatments for pain as a complement to opioid-based treatments. Here we show in male and female mice that enhancing levels of the eCB, 2-arachidonoylglycerol (2-AG), through pharmacological inhibition of its catabolic enzyme, monoacylglycerol lipase (MAGL), either systemically or in the ventral tegmental area (VTA) with JZL184, leads to a substantial attenuation of the rewarding effects of opioids in male and female mice using conditioned place preference and self-administration paradigms, without altering their analgesic properties. These effects are driven by CB1 receptors (CB1Rs) within the VTA as VTA CB1R conditional knockout, counteracts JZL184's effects. Conversely, pharmacologically enhancing the levels of the other eCB, anandamide (AEA), by inhibition of fatty acid amide hydrolase (FAAH) has no effect on opioid reward or analgesia. Using fiber photometry with fluorescent sensors for calcium and dopamine (DA), we find that enhancing 2-AG levels diminishes opioid reward-related nucleus accumbens (NAc) activity and DA neurotransmission. Together these findings reveal that 2-AG counteracts the rewarding properties of opioids and provides a potential adjunctive therapeutic strategy for opioid-related analgesic treatments.
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Affiliation(s)
- Arlene Martínez-Rivera
- Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia, PA, USA
- Division of Pediatric Neurology, Department of Pediatrics, Weill Cornell Medicine, New York, NY 10065, USA
| | - Robert N. Fetcho
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA
- Department of Psychiatry, Weill Cornell Medicine, New York, NY 10065, USA
| | - Lizzie Birmingham
- Department of Psychology, Temple University; Neuroscience Program, Temple University, 19122, USA
| | - Jin X Jiu
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ 07103, USA
| | - Ruirong Yang
- Department of Psychiatry, Weill Cornell Medicine, New York, NY 10065, USA
| | - Careen Foord
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA
| | - Diego Scala-Chávez
- Division of Pediatric Neurology, Department of Pediatrics, Weill Cornell Medicine, New York, NY 10065, USA
| | - Narmin Mekawy
- Division of Pediatric Neurology, Department of Pediatrics, Weill Cornell Medicine, New York, NY 10065, USA
| | - Kristen Pleil
- Department of Pharmacology, Weill Cornell Medicine, New York, NY 10065, USA
| | - Virginia M. Pickel
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA
| | - Conor Liston
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA
- Department of Psychiatry, Weill Cornell Medicine, New York, NY 10065, USA
| | - Carlos M. Castorena
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Joshua Levitz
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, 10065, USA
| | - Ying-Xian Pan
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ 07103, USA
| | - Lisa A. Briand
- Department of Psychology, Temple University; Neuroscience Program, Temple University, 19122, USA
| | - Anjali M. Rajadhyaksha
- Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia, PA, USA
- Division of Pediatric Neurology, Department of Pediatrics, Weill Cornell Medicine, New York, NY 10065, USA
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA
| | - Francis S. Lee
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA
- Department of Psychiatry, Weill Cornell Medicine, New York, NY 10065, USA
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Yadav-Samudrala BJ, Ravula HP, Barmada KM, Dodson H, Poklis JL, Ignatowska-Jankowska BM, Lichtman AH, Reissner KJ, Fitting S. Acute Effects of Monoacylglycerol Lipase Inhibitor ABX1431 on Neuronal Hyperexcitability, Nociception, Locomotion, and the Endocannabinoid System in HIV-1 Tat Male Mice. Cannabis Cannabinoid Res 2024. [PMID: 38394322 DOI: 10.1089/can.2023.0247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2024] Open
Abstract
Background: Evidence suggests that monoacylglycerol lipase (MAGL) inhibitors can potentially treat HIV symptoms by increasing the concentration of 2-arachidonoylglycerol (2-AG). We examined a selective MAGL inhibitor ABX1431 in the context of neuroHIV. Methods: To assess the effects of ABX1431, we conducted in vitro and in vivo studies. In vitro calcium imaging on frontal cortex neuronal cultures was performed to evaluate the role of ABX1431 (10, 30, 100 nM) on transactivator of transcription (Tat)-induced neuronal hyperexcitability. Following in vitro experiments, in vivo experiments were performed using Tat transgenic male mice. Mice were treated with 4 mg/kg ABX1431 and assessed for antinociception using tail-flick and hot plate assays followed by locomotor activity. After the behavioral experiments, their brains were harvested to quantify endocannabinoids (eCB) and related lipids through mass spectrometry, and cannabinoid type-1 and -2 receptors (CB1R and CB2R) were quantified through western blot. Results: In vitro studies revealed that adding Tat directly to the neuronal cultures significantly increased intracellular calcium concentration, which ABX1431 completely reversed at all concentrations. Preincubating the cultures with CB1R and CB2R antagonists showed that ABX1431 exhibited its effects partially through CB1R. In vivo studies demonstrated that acute ABX1431 increased overall total distance traveled and speed of mice regardless of their genotype. Mass spectrometry and western blot analyses revealed differential effects on the eCB system based on Tat expression. The 2-AG levels were significantly upregulated following ABX1431 treatment in the striatum and spinal cord. Arachidonic acid (AA) was also upregulated in the striatum of vehicle-treated Tat(+) mice. No changes were noted in CB1R expression levels; however, CB2R levels were increased in ABX1431-treated Tat(-) mice only. Conclusion: Findings indicate that ABX1431 has potential neuroprotective effects in vitro partially mediated through CB1R. Acute treatment of ABX1431 in vivo shows antinociceptive effects, and seems to alter locomotor activity, with upregulating 2-AG levels in the striatum and spinal cord.
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Affiliation(s)
- Barkha J Yadav-Samudrala
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Havilah P Ravula
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Karenna M Barmada
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Hailey Dodson
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Justin L Poklis
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, USA
| | | | - Aron H Lichtman
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Kathryn J Reissner
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Sylvia Fitting
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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Cannabinoid CB1 Receptors Are Expressed in a Subset of Dopamine Neurons and Underlie Cannabinoid-Induced Aversion, Hypoactivity, and Anxiolytic Effects in Mice. J Neurosci 2023; 43:373-385. [PMID: 36517243 PMCID: PMC9864584 DOI: 10.1523/jneurosci.1493-22.2022] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 10/12/2022] [Accepted: 11/12/2022] [Indexed: 12/23/2022] Open
Abstract
Cannabinoids modulate dopamine (DA) transmission and DA-related behavior, which has been thought to be mediated initially by activation of cannabinoid CB1 receptors (CB1Rs) on GABA neurons. However, there is no behavioral evidence supporting it. In contrast, here we report that CB1Rs are also expressed in a subset of DA neurons and functionally underlie cannabinoid action in male and female mice. RNAscope in situ hybridization (ISH) assays demonstrated CB1 mRNA in tyrosine hydroxylase (TH)-positive DA neurons in the ventral tegmental area (VTA) and glutamate decarboxylase 1 (GAD1)-positive GABA neurons. The CB1R-expressing DA neurons were located mainly in the middle portion of the VTA with the number of CB1-TH colocalization progressively decreasing from the medial to the lateral VTA. Triple-staining assays indicated CB1R mRNA colocalization with both TH and vesicular glutamate transporter 2 (VgluT2, a glutamate neuronal marker) in the medial VTA close to the midline of the brain. Optogenetic activation of this population of DA neurons was rewarding as assessed by optical intracranial self-stimulation. Δ9-tetrahydrocannabinol (Δ9-THC) or ACEA (a selective CB1R agonist) dose-dependently inhibited optical intracranial self-stimulation in DAT-Cre control mice, but not in conditional knockout mice with the CB1R gene absent in DA neurons. In addition, deletion of CB1Rs from DA neurons attenuated Δ9-THC-induced reduction in DA release in the NAc, locomotion, and anxiety. Together, these findings indicate that CB1Rs are expressed in a subset of DA neurons that corelease DA and glutamate, and functionally underlie cannabinoid modulation of DA release and DA-related behavior.SIGNIFICANCE STATEMENT Cannabinoids produce a series of psychoactive effects, such as aversion, anxiety, and locomotor inhibition in rodents. However, the cellular and receptor mechanisms underlying these actions are not fully understood. Here we report that CB1 receptors are expressed not only in GABA neurons but also in a subset of dopamine neurons, which are located mainly in the medial VTA close to the midline of the midbrain and corelease dopamine and glutamate. Optogenetic activation of these dopamine neurons is rewarding, which is dose-dependently inhibited by cannabinoids. Selective deletion of CB1 receptor from dopamine neurons blocked cannabinoid-induced aversion, hypoactivity, and anxiolytic effects. These findings demonstrate that dopaminergic CB1 receptors play an important role in mediating cannabinoid action.
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Neutral CB1 Receptor Antagonists as Pharmacotherapies for Substance Use Disorders: Rationale, Evidence, and Challenge. Cells 2022; 11:cells11203262. [PMID: 36291128 PMCID: PMC9600259 DOI: 10.3390/cells11203262] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 10/03/2022] [Accepted: 10/10/2022] [Indexed: 11/17/2022] Open
Abstract
Cannabinoid receptor 1 (CB1R) has been one of the major targets in medication development for treating substance use disorders (SUDs). Early studies indicated that rimonabant, a selective CB1R antagonist with an inverse agonist profile, was highly promising as a therapeutic for SUDs. However, its adverse side effects, such as depression and suicidality, led to its withdrawal from clinical trials worldwide in 2008. Consequently, much research interest shifted to developing neutral CB1R antagonists based on the recognition that rimonabant’s side effects may be related to its inverse agonist profile. In this article, we first review rimonabant’s research background as a potential pharmacotherapy for SUDs. Then, we discuss the possible mechanisms underlying its therapeutic anti-addictive effects versus its adverse effects. Lastly, we discuss the rationale for developing neutral CB1R antagonists as potential treatments for SUDs, the supporting evidence in recent research, and the challenges of this strategy. We conclude that developing neutral CB1R antagonists without inverse agonist profile may represent attractive strategies for the treatment of SUDs.
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Cai J, Tong Q. Anatomy and Function of Ventral Tegmental Area Glutamate Neurons. Front Neural Circuits 2022; 16:867053. [PMID: 35669454 PMCID: PMC9164627 DOI: 10.3389/fncir.2022.867053] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 03/30/2022] [Indexed: 11/29/2022] Open
Abstract
The ventral tegmental area (VTA) is well known for regulating reward consumption, learning, memory, and addiction behaviors through mediating dopamine (DA) release in downstream regions. Other than DA neurons, the VTA is known to be heterogeneous and contains other types of neurons, including glutamate neurons. In contrast to the well-studied and established functions of DA neurons, the role of VTA glutamate neurons is understudied, presumably due to their relatively small quantity and a lack of effective means to study them. Yet, emerging studies have begun to reveal the importance of glutamate release from VTA neurons in regulating diverse behavioral repertoire through a complex intra-VTA and long-range neuronal network. In this review, we summarize the features of VTA glutamate neurons from three perspectives, namely, cellular properties, neural connections, and behavioral functions. Delineation of VTA glutamatergic pathways and their interactions with VTA DA neurons in regulating behaviors may reveal previously unappreciated functions of the VTA in other physiological processes.
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Affiliation(s)
- Jing Cai
- Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, UTHealth McGovern Medical School, Houston, TX, United States
- Neuroscience Program, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States
| | - Qingchun Tong
- Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, UTHealth McGovern Medical School, Houston, TX, United States
- Neuroscience Program, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States
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6
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Epps SA. Commonalities for comorbidity: Overlapping features of the endocannabinoid system in depression and epilepsy. Front Psychiatry 2022; 13:1041460. [PMID: 36339877 PMCID: PMC9626804 DOI: 10.3389/fpsyt.2022.1041460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Accepted: 09/29/2022] [Indexed: 11/13/2022] Open
Abstract
A wealth of clinical and pre-clinical data supports a bidirectional comorbidity between depression and epilepsy. This suggests commonalities in underlying mechanisms that may serve as targets for more effective treatment strategies. Unfortunately, many patients with this comorbidity are highly refractory to current treatment strategies, while others experience a worsening of one arm of the comorbidity when treating the other arm. This highlights the need for novel pharmaceutical targets that may provide safe and effective relief for both depression and epilepsy symptoms. The endocannabinoid system (ECS) of the brain has become an area of intense interest for possible roles in depression and epilepsy. Several existing literature reviews have provided in-depth analysis of the involvement of various aspects of the ECS in depression or epilepsy separately, while others have addressed the effectiveness of different treatment strategies targeting the ECS in either condition individually. However, there is not currently a review that considers the ECS when both conditions are comorbid. This mini-review will address areas of common overlap between the ECS in depression and in epilepsy, such as commonalities in endocannabinoids themselves, their receptors, and degradative enzymes. These areas of overlap will be discussed alongside their implications for treatment of this challenging comorbidity.
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Affiliation(s)
- S Alisha Epps
- Department of Psychology, Whitworth University, Spokane, WA, United States
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Hempel B, Xi ZX. Receptor mechanisms underlying the CNS effects of cannabinoids: CB 1 receptor and beyond. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2021; 93:275-333. [PMID: 35341569 PMCID: PMC10709991 DOI: 10.1016/bs.apha.2021.10.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
Cannabis legalization continues to progress in many US states and other countries. Δ9-tetrahydrocannabinol (Δ9-THC) is the major psychoactive constituent in cannabis underlying both its abuse potential and the majority of therapeutic applications. However, the neural mechanisms underlying cannabis action are not fully understood. In this chapter, we first review recent progress in cannabinoid receptor research, and then examine the acute CNS effects of Δ9-THC or other cannabinoids (WIN55212-2) with a focus on their receptor mechanisms. In experimental animals, Δ9-THC or WIN55212-2 produces classical pharmacological effects (analgesia, catalepsy, hypothermia, hypolocomotion), biphasic changes in affect (reward vs. aversion, anxiety vs. anxiety relief), and cognitive deficits (spatial learning and memory, short-term memory). Accumulating evidence indicates that activation of CB1Rs underlies the majority of Δ9-THC or WIN55121-2's pharmacological and behavioral effects. Unexpectedly, glutamatergic CB1Rs preferentially underlie cannabis action relative to GABAergic CB1Rs. Functional roles for CB1Rs expressed on astrocytes and mitochondria have also been uncovered. In addition, Δ9-THC or WIN55212-2 is an agonist at CB2R, GPR55 and PPARγ receptors and recent studies implicate these receptors in a number of their CNS effects. Other receptors (such as serotonin, opioid, and adenosine receptors) also modulate Δ9-THC's actions and their contributions are detailed. This chapter describes the neural mechanisms underlying cannabis action, which may lead to new discoveries in cannabis-based medication development for the treatment of cannabis use disorder and other human diseases.
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Affiliation(s)
- Briana Hempel
- Addiction Biology Unit, Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse, Baltimore, MD, United States
| | - Zheng-Xiong Xi
- Addiction Biology Unit, Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse, Baltimore, MD, United States.
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8
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Humburg BA, Jordan CJ, Zhang H, Shen H, Han X, Bi G, Hempel B, Galaj E, Baumann MH, Xi Z. Optogenetic brain-stimulation reward: A new procedure to re-evaluate the rewarding versus aversive effects of cannabinoids in dopamine transporter-Cre mice. Addict Biol 2021; 26:e13005. [PMID: 33538103 DOI: 10.1111/adb.13005] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 12/04/2020] [Accepted: 01/09/2021] [Indexed: 12/12/2022]
Abstract
Despite extensive research, the rewarding effects of cannabinoids are still debated. Here, we used a newly established animal procedure called optogenetic intracranial self-stimulation (ICSS) (oICSS) to re-examine the abuse potential of cannabinoids in mice. A specific adeno-associated viral vector carrying a channelrhodopsin gene was microinjected into the ventral tegmental area (VTA) to express light-sensitive channelrhodopsin in dopamine (DA) neurons of transgenic dopamine transporter (DAT)-Cre mice. Optogenetic stimulation of VTA DA neurons was highly reinforcing and produced a classical "sigmoidal"-shaped stimulation-response curve dependent upon the laser pulse frequency. Systemic administration of cocaine dose-dependently enhanced oICSS and shifted stimulation-response curves upward, in a way similar to previously observed effects of cocaine on electrical ICSS. In contrast, Δ9 -tetrahydrocannabinol (Δ9 -THC), but not cannabidiol, dose-dependently decreased oICSS responding and shifted oICSS curves downward. WIN55,212-2 and ACEA, two synthetic cannabinoids often used in laboratory settings, also produced dose-dependent reductions in oICSS. We then examined several new synthetic cannabinoids, which are used recreationally. XLR-11 produced a cocaine-like increase, AM-2201 produced a Δ9 -THC-like reduction, while 5F-AMB had no effect on oICSS responding. Immunohistochemistry and RNAscope in situ hybridization assays indicated that CB1 Rs are expressed mainly in VTA GABA and glutamate neurons, while CB2 Rs are expressed mainly in VTA DA neurons. Together, these findings suggest that most cannabinoids are not reward enhancing, but rather reward attenuating or aversive in mice. Activation of CB1 R and/or CB2 R in different populations of neurons in the brain may underlie the observed actions.
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Affiliation(s)
- Bree A. Humburg
- Addiction Biology Unit, Molecular Targets and Medications Discovery, Intramural Research Program National Institute on Drug Abuse Baltimore Maryland USA
| | - Chloe J. Jordan
- Addiction Biology Unit, Molecular Targets and Medications Discovery, Intramural Research Program National Institute on Drug Abuse Baltimore Maryland USA
| | - Hai‐Ying Zhang
- Addiction Biology Unit, Molecular Targets and Medications Discovery, Intramural Research Program National Institute on Drug Abuse Baltimore Maryland USA
| | - Hui Shen
- Synaptic Plasticity Section, Intramural Research Program National Institute on Drug Abuse Baltimore Maryland USA
| | - Xiao Han
- Addiction Biology Unit, Molecular Targets and Medications Discovery, Intramural Research Program National Institute on Drug Abuse Baltimore Maryland USA
| | - Guo‐Hua Bi
- Addiction Biology Unit, Molecular Targets and Medications Discovery, Intramural Research Program National Institute on Drug Abuse Baltimore Maryland USA
| | - Briana Hempel
- Addiction Biology Unit, Molecular Targets and Medications Discovery, Intramural Research Program National Institute on Drug Abuse Baltimore Maryland USA
| | - Ewa Galaj
- Addiction Biology Unit, Molecular Targets and Medications Discovery, Intramural Research Program National Institute on Drug Abuse Baltimore Maryland USA
| | - Michael H. Baumann
- Designer Drug Research Unit, Intramural Research Program National Institute on Drug Abuse Baltimore Maryland USA
| | - Zheng‐Xiong Xi
- Addiction Biology Unit, Molecular Targets and Medications Discovery, Intramural Research Program National Institute on Drug Abuse Baltimore Maryland USA
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Diester CM, Lichtman AH, Negus SS. Behavioral Battery for Testing Candidate Analgesics in Mice. II. Effects of Endocannabinoid Catabolic Enzyme Inhibitors and ∆9-Tetrahydrocannabinol. J Pharmacol Exp Ther 2021; 377:242-253. [PMID: 33622769 PMCID: PMC8058502 DOI: 10.1124/jpet.121.000497] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 02/22/2021] [Indexed: 12/19/2022] Open
Abstract
Enhanced signaling of the endocannabinoid (eCB) system through inhibition of the catabolic enzymes monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH) has received increasing interest for development of candidate analgesics. This study compared effects of MAGL and FAAH inhibitors with effects of ∆9-tetrahydrocannabinol (THC) using a battery of pain-stimulated, pain-depressed, and pain-independent behaviors in male and female mice. Intraperitoneal injection of dilute lactic acid (IP acid) served as an acute visceral noxious stimulus to stimulate two behaviors (stretching, facial grimace) and depress two behaviors (rearing, nesting). Nesting and locomotion were also assessed in the absence of IP acid as pain-independent behaviors. THC and a spectrum of six eCB catabolic enzyme inhibitors ranging from MAGL- to FAAH-selective were assessed for effectiveness to alleviate pain-related behaviors at doses that did not alter pain-independent behaviors. The MAGL-selective inhibitor MJN110 produced the most effective antinociceptive profile, with 1.0 mg/kg alleviating IP acid effects on stretching, grimace, and nesting without altering pain-independent behaviors. MJN110 effects on IP acid-depressed nesting had a slow onset and long duration (40 minutes to 6 hours), were blocked by rimonabant, and tended to be greater in females. As inhibitors increased in FAAH selectivity, antinociceptive effectiveness decreased. PF3845, the most FAAH-selective inhibitor, produced no antinociception up to doses that disrupted locomotion. THC decreased IP acid-stimulated stretching and grimace at doses that did not alter pain-independent behaviors; however, it did not alleviate IP acid-induced depression of rearing or nesting. These results support further consideration of MAGL-selective inhibitors as candidate analgesics for acute inflammatory pain. SIGNIFICANCE STATEMENT: This study characterized a spectrum of endocannabinoid catabolic enzyme inhibitors ranging in selectivity from monoacylglycerol lipase-selective to fatty acid amide hydrolase-selective in a battery of pain-stimulated, pain-depressed, and pain-independent behaviors previously pharmacologically characterized in a companion paper. This battery provides a method for prioritizing candidate analgesics by effectiveness to alleviate pain-related behaviors at doses that do not alter pain-independent behaviors, with inclusion of pain-depressed behaviors increasing translational validity and decreasing susceptibility to motor-depressant false positives.
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Affiliation(s)
- C M Diester
- Department of Pharmacology and Toxicology (C.M.D., A.H.L., S.S.N.), School of Pharmacy (A.H.L.), Virginia Commonwealth University, Richmond, Virginia
| | - A H Lichtman
- Department of Pharmacology and Toxicology (C.M.D., A.H.L., S.S.N.), School of Pharmacy (A.H.L.), Virginia Commonwealth University, Richmond, Virginia
| | - S S Negus
- Department of Pharmacology and Toxicology (C.M.D., A.H.L., S.S.N.), School of Pharmacy (A.H.L.), Virginia Commonwealth University, Richmond, Virginia
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10
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Hurel I, Muguruza C, Redon B, Marsicano G, Chaouloff F. Cannabis and exercise: Effects of Δ 9-tetrahydrocannabinol on preference and motivation for wheel-running in mice. Prog Neuropsychopharmacol Biol Psychiatry 2021; 105:110117. [PMID: 32971218 DOI: 10.1016/j.pnpbp.2020.110117] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/11/2020] [Accepted: 09/20/2020] [Indexed: 11/27/2022]
Abstract
Recent surveys have revealed close links between cannabis and exercise. Specifically, cannabis usage before and/or after exercise is an increasingly common habit primarily aimed at boosting exercise pleasure, motivation, and performance whilst facilitating post-exercise recovery. However, whether these beliefs reflect the true impact of cannabis on these aspects of exercise is unknown. This study has thus examined the effects of cannabis' main psychoactive ingredient, namely Δ9-tetrahydrocannabinol (THC), on (i) mouse wheel-running preference and performance and (ii) running motivation and seeking behaviour. Wheel-running preference and performance were investigated using a T-maze with free and locked wheels located at the extremity of either arm. Running motivation and seeking were assessed by a cued-running operant task wherein wheel-running was conditioned by nose poking. Moreover, because THC targets cannabinoid type 1 (CB1) receptors, i.e. receptors previously documented to control running motivation, this study also assessed the role of these receptors in running preference, performance, and craving-like behaviour. Whilst acute blockade or genetic deletion of CB1 receptors decreased running preference and performance in the T-maze, THC proved ineffective on either variable. The failure of THC to affect running variables in the T-maze extended to running motivation, as assessed by cued-running under a progressive ratio (PR) reinforcement schedule. This ineffectiveness of THC was not related to the treatment protocol because it successfully increased motivation for palatable food. Although craving-like behaviour, as indexed by a cue-induced reinstatement of running seeking, was found to depend on CB1 receptors, THC again proved ineffective. Neither running motivation nor running seeking were affected when CB1 receptors were further stimulated by increasing the levels of the endocannabinoid 2-arachidonoylglycerol. These results, which suggest that the drive for running is insensitive to the acute stimulation of CB1 receptors, raise the hypothesis that cannabis is devoid of effect on exercise motivation. Future investigation using chronic administration of THC, with and without other cannabis ingredients (e.g. cannabidiol), is however required before conclusions can be drawn.
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Affiliation(s)
- Imane Hurel
- Endocannabinoids and NeuroAdaptation, NeuroCentre INSERM U1215, 33077 Bordeaux, France; Université de Bordeaux, 33077 Bordeaux, France
| | - Carolina Muguruza
- Endocannabinoids and NeuroAdaptation, NeuroCentre INSERM U1215, 33077 Bordeaux, France; Université de Bordeaux, 33077 Bordeaux, France; Department of Pharmacology, University of the Basque Country UPV/EHU, Leioa, Bizkaia, Spain; Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Spain
| | - Bastien Redon
- Endocannabinoids and NeuroAdaptation, NeuroCentre INSERM U1215, 33077 Bordeaux, France; Université de Bordeaux, 33077 Bordeaux, France
| | - Giovanni Marsicano
- Endocannabinoids and NeuroAdaptation, NeuroCentre INSERM U1215, 33077 Bordeaux, France; Université de Bordeaux, 33077 Bordeaux, France
| | - Francis Chaouloff
- Endocannabinoids and NeuroAdaptation, NeuroCentre INSERM U1215, 33077 Bordeaux, France; Université de Bordeaux, 33077 Bordeaux, France.
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11
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Bjork JM. The ups and downs of relating nondrug reward activation to substance use risk in adolescents. CURRENT ADDICTION REPORTS 2021; 7:421-429. [PMID: 33585160 DOI: 10.1007/s40429-020-00327-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Purpose of review A wealth of epidemiological and cohort research, together with a healthy dose of anecdote, has characterized late-adolescence and emerging adulthood as a time of increased substance use and other risky behaviors. This review will address whether differences between adolescents or between adolescents and other age groups in dopaminergic mesolimbic recruitment by (non-drug) rewards inferred from functional magnetic resonance imaging (fMRI) could partially explain morbidity and mortality from risky-behavior-related causes in adolescents. Recent findings Recent findings do not suggest a definitive directionality with regard to whether increased vs decreased mesolimbic responsiveness to nondrug rewards correlates with real-world risk-taking. Inconsistent relationships between reward-activation and real-world risky behavior in these reports reflect in part methodological differences as well as conceptual differences between populations in terms of whether tepid mesolimbic recruitment by rewards is a marker of psychiatric health. Summary There are several potential reasons why the directionality of relationships between reward-elicited brain activation and substance use risk (specifically) might differ. These factors include differences between adolescents in histories/exposure of substance use, motivation for substance use, the component of the instrumental behavior being studied, and the cognitive demands of the incentive tasks. Systematic manipulation of these discrepant study factors might offer a way forward to clarify how motivational neurocircuit function relates to addiction risk in adolescents.
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Affiliation(s)
- James M Bjork
- Institute for Drug and Alcohol Studies, Virginia Commonwealth University
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12
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Li X, Hempel BJ, Yang HJ, Han X, Bi GH, Gardner EL, Xi ZX. Dissecting the role of CB 1 and CB 2 receptors in cannabinoid reward versus aversion using transgenic CB 1- and CB 2-knockout mice. Eur Neuropsychopharmacol 2021; 43:38-51. [PMID: 33334652 PMCID: PMC7854511 DOI: 10.1016/j.euroneuro.2020.11.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 10/28/2020] [Accepted: 11/30/2020] [Indexed: 12/21/2022]
Abstract
Cannabinoids produce both rewarding and aversive effects in humans and experimental animals. However, the mechanisms underlying these conflicting findings are unclear. Here we examined the potential involvement of CB1 and CB2 receptors in cannabinoid action using transgenic CB1-knockout (CB1-KO) and CB2-knockout (CB2-KO) mice. We found that Δ9-tetrahydrocannabinol (Δ9-THC) induced conditioned place preference at a low dose (1 mg/kg) in WT mice that was attenuated by deletion of the CB1 receptor. At 5 mg/kg, no subjective effects of Δ9-THC were detected in WT mice, but CB1-KO mice exhibited a trend towards place aversion and CB2-KO mice developed significant place preferences. This data suggests that activation of the CB1 receptor is rewarding, while CB2R activation is aversive. We then examined the nucleus accumbens (NAc) dopamine (DA) response to Δ9-THC using in vivo microdialysis. Unexpectedly, Δ9-THC produced a dose-dependent decrease in extracellular DA in WT mice, that was potentiated in CB1-KO mice. However, in CB2-KO mice Δ9-THC produced a dose-dependent increase in extracellular DA, suggesting that activation of the CB2R inhibits DA release in the NAc. In contrast, Δ9-THC, when administered systemically or locally into the NAc, failed to alter extracellular DA in rats. Lastly, we examined the locomotor response to Δ9-THC. Both CB1 and CB2 receptor mechanisms were shown to underlie Δ9-THC-induced hypolocomotion. These findings indicate that Δ9-THC's variable subjective effects reflect differential activation of cannabinoid receptors. Specifically, the opposing actions of CB1 and CB2 receptors regulate cannabis reward and aversion, with CB2-mediated effects predominant in mice.
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Affiliation(s)
- Xia Li
- Molecular Targets and Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, 251 Bayview Blvd, NIDA IRP, BRC Suite 200, Baltimore, MD 21224, USA; Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Briana J Hempel
- Molecular Targets and Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, 251 Bayview Blvd, NIDA IRP, BRC Suite 200, Baltimore, MD 21224, USA
| | - Hong-Ju Yang
- Molecular Targets and Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, 251 Bayview Blvd, NIDA IRP, BRC Suite 200, Baltimore, MD 21224, USA
| | - Xiao Han
- Molecular Targets and Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, 251 Bayview Blvd, NIDA IRP, BRC Suite 200, Baltimore, MD 21224, USA
| | - Guo-Hua Bi
- Molecular Targets and Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, 251 Bayview Blvd, NIDA IRP, BRC Suite 200, Baltimore, MD 21224, USA
| | - Eliot L Gardner
- Molecular Targets and Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, 251 Bayview Blvd, NIDA IRP, BRC Suite 200, Baltimore, MD 21224, USA
| | - Zheng-Xiong Xi
- Molecular Targets and Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, 251 Bayview Blvd, NIDA IRP, BRC Suite 200, Baltimore, MD 21224, USA.
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13
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Attenuated dopamine receptor signaling in nucleus accumbens core in a rat model of chemically-induced neuropathy. Neuropharmacology 2020; 166:107935. [PMID: 31917153 DOI: 10.1016/j.neuropharm.2020.107935] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 12/10/2019] [Accepted: 01/02/2020] [Indexed: 02/06/2023]
Abstract
Neuropathy is major source of chronic pain that can be caused by mechanically or chemically induced nerve injury. Intraplantar formalin injection produces local necrosis over a two-week period and has been used to model neuropathy in rats. To determine whether neuropathy alters dopamine (DA) receptor responsiveness in mesolimbic brain regions, we examined dopamine D1-like and D2-like receptor (D1/2R) signaling and expression in male rats 14 days after bilateral intraplantar formalin injections into both rear paws. D2R-mediated G-protein activation and expression of the D2R long, but not short, isoform were reduced in nucleus accumbens (NAc) core, but not in NAc shell, caudate-putamen or ventral tegmental area of formalin- compared to saline-treated rats. In addition, D1R-stimulated adenylyl cyclase activity was also reduced in NAc core, but not in NAc shell or prefrontal cortex, of formalin-treated rats, whereas D1R expression was unaffected. Other proteins involved in dopamine neurotransmission, including dopamine uptake transporter and tyrosine hydroxylase, were unaffected by formalin treatment. In behavioral tests, the potency of a D2R agonist to suppress intracranial self-stimulation (ICSS) was decreased in formalin-treated rats, whereas D1R agonist effects were not altered. The combination of reduced D2R expression and signaling in NAc core with reduced suppression of ICSS responding by a D2R agonist suggest a reduction in D2 autoreceptor function. Altogether, these results indicate that intraplantar formalin produces attenuation of highly specific DA receptor signaling processes in NAc core of male rats and suggest the development of a neuropathy-induced allostatic state in both pre- and post-synaptic DA receptor function.
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14
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Feja M, Leigh MPK, Baindur AN, McGraw JJ, Wakabayashi KT, Cravatt BF, Bass CE. The novel MAGL inhibitor MJN110 enhances responding to reward-predictive incentive cues by activation of CB1 receptors. Neuropharmacology 2020; 162:107814. [PMID: 31628934 PMCID: PMC6983961 DOI: 10.1016/j.neuropharm.2019.107814] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 10/14/2019] [Accepted: 10/14/2019] [Indexed: 11/17/2022]
Abstract
CB1 receptor antagonists disrupt operant responding for food and drug reinforcers, and cue-induced reinstatement of cocaine and heroin seeking. Conversely, enhancing endocannabinoid signaling, particularly 2-arachidonyl glycerol (2-AG), by inhibition of monoacyl glycerol lipase (MAGL), may facilitate some aspects of reward seeking. To determine how endocannabinoid signaling affects responding to reward-predictive cues, we employed an operant task that allows us to parse the incentive motivational properties of cues. Rats were required to nosepoke during an intermittent audiovisual incentive cue (IC) to obtain a 10% sucrose reward. The CB1 receptor antagonist, rimonabant, dose-dependently decreased the response ratio (rewarded ICs/total presented) and active nosepokes per IC, while it increased the latency to respond to the cue and obtain the reward, indicating an overall decrease in both the choice and vigor of responding. Yet rats persisted in entering the reward cup. Using a modified version of the task, the novel MAGL inhibitor MJN110 increased the response ratio, decreased the latencies to respond to the IC and enhanced active nosepokes per IC, indicating a facilitation of cue-induced reward seeking. These effects were blocked by a subthreshold dose of rimonabant. Finally, MJN110 did not alter consumption of freely available sucrose within volumes obtained in the operant task. Together these data demonstrate blocking endocannabinoid tone at the CB1 receptor attenuates the ability of cues to induce reward seeking, while some aspects of motivation for the reward are retained. Conversely, enhancing 2-AG signaling at CB1 receptors facilitates IC responding and increases the motivational properties of the IC.
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Affiliation(s)
- Malte Feja
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, 955 Main St, Buffalo, NY, 14203, USA.
| | - Martin P K Leigh
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, 955 Main St, Buffalo, NY, 14203, USA.
| | - Ajay N Baindur
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, 955 Main St, Buffalo, NY, 14203, USA.
| | - Justin J McGraw
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, 955 Main St, Buffalo, NY, 14203, USA.
| | - Ken T Wakabayashi
- Department of Psychology, University of Nebraska-Lincoln, 1220 T. Street, Lincoln, NE, 68503, USA.
| | - Benjamin F Cravatt
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA.
| | - Caroline E Bass
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, 955 Main St, Buffalo, NY, 14203, USA.
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Abstract
Substance use disorder (SUD) is a major public health crisis worldwide, and effective treatment options are limited. During the past 2 decades, researchers have investigated the impact of a variety of pharmacological approaches to treat SUD, one of which is the use of medical cannabis or cannabinoids. Significant progress was made with the discovery of rimonabant, a selective CB1 receptor (CB1R) antagonist (also an inverse agonist), as a promising therapeutic for SUDs and obesity. However, serious adverse effects such as depression and suicidality led to the withdrawal of rimonabant (and almost all other CB1R antagonists/inverse agonists) from clinical trials worldwide in 2008. Since then, much research interest has shifted to other cannabinoid-based strategies, such as peripheral CB1R antagonists/inverse agonists, neutral CB1R antagonists, allosteric CB1R modulators, CB2R agonists, fatty acid amide hydrolase (FAAH) inhibitors, monoacylglycerol lipase (MAGL) inhibitors, fatty acid binding protein (FABP) inhibitors, or nonaddictive phytocannabinoids with CB1R or CB2R-binding profiles, as new therapeutics for SUDs. In this article, we first review recent progress in research regarding the endocannabinoid systems, cannabis reward versus aversion, and the underlying receptor mechanisms. We then review recent progress in cannabinoid-based medication development for the treatment of SUDs. As evidence continues to accumulate, neutral CB1R antagonists (such as AM4113), CB2R agonists (JWH133, Xie2-64), and nonselective phytocannabinoids (cannabidiol, β-caryophyllene, ∆9-tetrahydrocannabivarin) have shown great therapeutic potential for SUDs, as shown in experimental animals. Several cannabinoid-based medications (e.g., dronabinol, nabilone, PF-04457845) that entered clinical trials have shown promising results in reducing withdrawal symptoms in cannabis and opioid users.
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Affiliation(s)
- Ewa Galaj
- Addiction Biology Unit, Molecular Targets and Medication Discoveries Branch, Intramural Research Program, National Institute on Drug Abuse, Baltimore, MD, 21224, USA
| | - Zheng-Xiong Xi
- Addiction Biology Unit, Molecular Targets and Medication Discoveries Branch, Intramural Research Program, National Institute on Drug Abuse, Baltimore, MD, 21224, USA.
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16
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Spiller KJ, Bi GH, He Y, Galaj E, Gardner EL, Xi ZX. Cannabinoid CB 1 and CB 2 receptor mechanisms underlie cannabis reward and aversion in rats. Br J Pharmacol 2019; 176:1268-1281. [PMID: 30767215 DOI: 10.1111/bph.14625] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 12/11/2018] [Accepted: 01/30/2019] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND AND PURPOSE Endocannabinoids are critically involved in brain reward functions, mediated by activation of CB1 receptors, reflecting their high density in the brain. However, the recent discovery of CB2 receptors in the brain, particularly in the midbrain dopamine neurons, has challenged this view and inspired us to re-examine the roles of both CB1 and CB2 receptors in the effects of cannabis. EXPERIMENTAL APPROACH In the present study, we used the electrical intracranial self-stimulation paradigm to evaluate the effects of various cannabinoid drugs on brain reward in laboratory rats and the roles of CB1 and CB2 receptors activation in brain reward function(s). KEY RESULTS Two mixed CB1 / CB2 receptor agonists, Δ9 -tetrahydrocannabinol (Δ9 -THC) and WIN55,212-2, produced biphasic effects-mild enhancement of brain-stimulation reward (BSR) at low doses but inhibition at higher doses. Pretreatment with a CB1 receptor antagonist (AM251) attenuated the low dose-enhanced BSR, while a CB2 receptor antagonist (AM630) attenuated high dose-inhibited BSR. To confirm these opposing effects, rats were treated with selective CB1 and CB2 receptor agonists. These compounds produced significant BSR enhancement and inhibition, respectively. CONCLUSIONS AND IMPLICATIONS CB1 receptor activation produced reinforcing effects, whereas CB2 receptor activation was aversive. The subjective effects of cannabis depend on the balance of these opposing effects. These findings not only explain previous conflicting results in animal models of addiction but also explain why cannabis can be either rewarding or aversive in humans, as expression of CB1 and CB2 receptors may differ in the brains of different subjects.
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Affiliation(s)
- Krista J Spiller
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Guo-Hua Bi
- Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse, Baltimore, Maryland, USA
| | - Yi He
- Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse, Baltimore, Maryland, USA
| | - Ewa Galaj
- Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse, Baltimore, Maryland, USA
| | - Eliot L Gardner
- Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse, Baltimore, Maryland, USA
| | - Zheng-Xiong Xi
- Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse, Baltimore, Maryland, USA
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17
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Scherma M, Masia P, Satta V, Fratta W, Fadda P, Tanda G. Brain activity of anandamide: a rewarding bliss? Acta Pharmacol Sin 2019; 40:309-323. [PMID: 30050084 DOI: 10.1038/s41401-018-0075-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 05/20/2018] [Indexed: 12/11/2022] Open
Abstract
Anandamide is a lipid mediator that acts as an endogenous ligand of CB1 receptors. These receptors are also the primary molecular target responsible for the pharmacological effects of Δ9-tetrahydrocannabinol, the psychoactive ingredient in Cannabis sativa. Several studies demonstrate that anandamide exerts an overall modulatory effect on the brain reward circuitry. Several reports suggest its involvement in the addiction-producing actions of other abused drugs, and it can also act as a behavioral reinforcer in animal models of drug abuse. Importantly, all these effects of anandamide appear to be potentiated by pharmacological inhibition of its metabolic degradation. Enhanced brain levels of anandamide after treatment with inhibitors of fatty acid amide hydrolase, the main enzyme responsible for its degradation, seem to affect the rewarding and reinforcing actions of many drugs of abuse. In this review, we will provide an overview from a preclinical perspective of the current state of knowledge regarding the behavioral pharmacology of anandamide, with a particular emphasis on its motivational/reinforcing properties. We will also discuss how modulation of anandamide levels through inhibition of enzymatic metabolic pathways could provide a basis for developing new pharmaco-therapeutic tools for the treatment of substance use disorders.
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18
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Nawata Y, Yamaguchi T, Fukumori R, Yamamoto T. Inhibition of Monoacylglycerol Lipase Reduces the Reinstatement of Methamphetamine-Seeking and Anxiety-Like Behaviors in Methamphetamine Self-Administered Rats. Int J Neuropsychopharmacol 2018; 22:165-172. [PMID: 30481332 PMCID: PMC6368370 DOI: 10.1093/ijnp/pyy086] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Methamphetamine is a highly addictive psychostimulant with reinforcing properties. Our laboratory previously found that Δ8-tetrahydrocannabinol, an exogenous cannabinoid, suppressed the reinstatement of methamphetamine-seeking behavior. The purpose of this study was to determine whether the elevation of endocannabinoids modulates the reinstatement of methamphetamine-seeking behavior and emotional changes in methamphetamine self-administered rats. METHODS Rats were tested for the reinstatement of methamphetamine-seeking behavior following methamphetamine self-administration and extinction. The elevated plus-maze test was performed in methamphetamine self-administered rats during withdrawal. We investigated the effects of JZL184 and URB597, 2 inhibitors of endocannabinoid hydrolysis, on the reinstatement of methamphetamine-seeking and anxiety-like behaviors. RESULTS JZL184 (32 and 40 mg/kg, i.p.), an inhibitor of monoacylglycerol lipase, significantly attenuated both the cue- and stress-induced reinstatement of methamphetamine-seeking behavior. Furthermore, URB597 (3.2 and 10 mg/kg, i.p.), an inhibitor of fatty acid amide hydrolase, attenuated only cue-induced reinstatement. AM251, a cannabinoid CB1 receptor antagonist, antagonized the attenuation of cue-induced reinstatement by JZL184 but not URB597. Neither JZL184 nor URB597 reinstated methamphetamine-seeking behavior when administered alone. In the elevated plus-maze test, rats that were in withdrawal from methamphetamine self-administration spent less time in the open arms. JZL184 ameliorated the decrease in time spent in the open arms. CONCLUSION We showed that JZL184 reduced both the cue- and stress-induced reinstatement of methamphetamine-seeking and anxiety-like behaviors in rats that had self-administered methamphetamine. It was suggested that a decrease in 2-arachidonoylglycerol in the brain could drive the reinstatement of methamphetamine-seeking and anxiety-like behaviors.
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Affiliation(s)
- Yoko Nawata
- Department of Pharmacology, Faculty of Pharmaceutical Science, Nagasaki International University, Nagasaki, Japan
| | - Taku Yamaguchi
- Department of Pharmacology, Faculty of Pharmaceutical Science, Nagasaki International University, Nagasaki, Japan
| | - Ryo Fukumori
- Department of Pharmacology, Faculty of Pharmaceutical Science, Nagasaki International University, Nagasaki, Japan
| | - Tsuneyuki Yamamoto
- Department of Pharmacology, Faculty of Pharmaceutical Science, Nagasaki International University, Nagasaki, Japan,Correspondence: Tsuneyuki Yamamoto, PhD, Department of Pharmacology, Faculty of Pharmaceutical Science, Nagasaki International University, 2825–7 Huis Ten Bosch Sasebo, Nagasaki 859–3298, Japan ()
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19
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Lupica CR, Hoffman AF. Cannabinoid disruption of learning mechanisms involved in reward processing. ACTA ACUST UNITED AC 2018; 25:435-445. [PMID: 30115765 PMCID: PMC6097761 DOI: 10.1101/lm.046748.117] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 07/06/2018] [Indexed: 02/06/2023]
Abstract
The increasing use of cannabis, its derivatives, and synthetic cannabinoids for medicinal and recreational purposes has led to burgeoning interest in understanding the addictive potential of this class of molecules. It is estimated that ∼10% of marijuana users will eventually show signs of dependence on the drug, and the diagnosis of cannabis use disorder (CUD) is increasing in the United States. The molecule that sustains the use of cannabis is Δ9-tetrahydrocannabinol (Δ9-THC), and our knowledge of its effects, and those of other cannabinoids on brain function has expanded rapidly in the past two decades. Additionally, the identification of endogenous cannabinoid (endocannabinoid) systems in brain and their roles in physiology and behavior, demonstrate extensive involvement of these lipid signaling molecules in regulating CNS function. Here, we examine roles for endogenous cannabinoids in shaping synaptic activity in cortical and subcortical brain circuits, and we discuss mechanisms in which exogenous cannabinoids, such as Δ9-THC, interact with endocannabinoid systems to disrupt neuronal network oscillations. We then explore how perturbation of the interaction of this activity within brain reward circuits may lead to impaired learning. Finally, we propose that disruption of cellular plasticity mechanisms by exogenous cannabinoids in cortical and subcortical circuits may explain the difficulty in establishing viable cannabinoid self-administration models in animals.
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Affiliation(s)
- Carl R Lupica
- Electrophysiology Research Section, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224, USA
| | - Alexander F Hoffman
- Electrophysiology Research Section, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224, USA
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20
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Hermes DJ, Xu C, Poklis JL, Niphakis MJ, Cravatt BF, Mackie K, Lichtman AH, Ignatowska-Jankowska BM, Fitting S. Neuroprotective effects of fatty acid amide hydrolase catabolic enzyme inhibition in a HIV-1 Tat model of neuroAIDS. Neuropharmacology 2018; 141:55-65. [PMID: 30114402 DOI: 10.1016/j.neuropharm.2018.08.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 07/20/2018] [Accepted: 08/12/2018] [Indexed: 12/16/2022]
Abstract
The HIV-1 transactivator of transcription (Tat) is a neurotoxin involved in the pathogenesis of HIV-1 associated neurocognitive disorders (HAND). The neurotoxic effects of Tat are mediated directly via AMPA/NMDA receptor activity and indirectly through neuroinflammatory signaling in glia. Emerging strategies in the development of neuroprotective agents involve the modulation of the endocannabinoid system. A major endocannabinoid, anandamide (N-arachidonoylethanolamine, AEA), is metabolized by fatty acid amide hydrolase (FAAH). Here we demonstrate using a murine prefrontal cortex primary culture model that the inhibition of FAAH, using PF3845, attenuates Tat-mediated increases in intracellular calcium, neuronal death, and dendritic degeneration via cannabinoid receptors (CB1R and CB2R). Live cell imaging was used to assess Tat-mediated increases in [Ca2+]i, which was significantly reduced by PF3845. A time-lapse assay revealed that Tat potentiates cell death while PF3845 blocks this effect. Additionally PF3845 blocked the Tat-mediated increase in activated caspase-3 (apoptotic marker) positive neurons. Dendritic degeneration was characterized by analyzing stained dendritic processes using Imaris and Tat was found to significantly decrease the size of processes while PF3845 inhibited this effect. Incubation with CB1R and CB2R antagonists (SR141716A and AM630) revealed that PF3845-mediated calcium effects were dependent on CB1R, while reduced neuronal death and degeneration was CB2R-mediated. PF3845 application led to increased levels of AEA, suggesting the observed effects are likely a result of increased endocannabinoid signaling at CB1R/CB2R. Our findings suggest that modulation of the endogenous cannabinoid system through inhibition of FAAH may be beneficial in treatment of HAND.
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Affiliation(s)
- Douglas J Hermes
- Department of Psychology & Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| | - Changqing Xu
- Department of Psychology & Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Justin L Poklis
- Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Micah J Niphakis
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, CA 92037, USA
| | - Benjamin F Cravatt
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, CA 92037, USA
| | - Ken Mackie
- Department of Psychological & Brain Science, Indiana University Bloomington, Bloomington, IN 47405, USA
| | - Aron H Lichtman
- Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | | | - Sylvia Fitting
- Department of Psychology & Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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21
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Khatri D, Laroche G, Grant ML, Jones VM, Vetreno RP, Crews FT, Mukhopadhyay S. Acute Ethanol Inhibition of Adult Hippocampal Neurogenesis Involves CB1 Cannabinoid Receptor Signaling. Alcohol Clin Exp Res 2018; 42:718-726. [PMID: 29417597 DOI: 10.1111/acer.13608] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 01/30/2018] [Indexed: 12/26/2022]
Abstract
BACKGROUND Chronic ethanol (EtOH) exposure has been found to inhibit adult hippocampal neurogenesis in multiple models of alcohol addiction. However, acute EtOH inhibition of adult neurogenesis is not well studied. Although many abused drugs have been found to inhibit adult neurogenesis, few have studied cannabinoids or cannabinoids with EtOH, although human use of both together is becoming more common. We used an acute binge alcohol drinking model in combination with select cannabinoid receptor agonists and antagonists to investigate the actions of each alone and together on hippocampal neurogenesis. METHODS Adult male Wistar rats were treated with an acute binge dose of EtOH (5 g/kg, i.g.), cannabinoid 1 receptor (CB1R) or cannabinoid 2 receptor (CB2R) agonists, as well as selective cannabinoid (CB) antagonists, alone or combined. Hippocampal doublecortin (DCX), Ki67, and activated cleaved caspase-3 (CC3) immunohistochemistry were used to assess neurogenesis, neuroprogenitor proliferation, and cell death, respectively. RESULTS We found that treatment with EtOH or the CB1R agonist, arachidonoyl-2'-chloroethylamide (ACEA), and the combination significantly reduced DCX-positive neurons (DCX + IR) in dentate gyrus (DG) and increased CC3. Further, using an inhibitor of endocannabinoid metabolism, for example, JZL195, we also found reduced DCX + IR neurogenesis. Treatment with 2 different CB1R antagonists (AM251 or SR141716) reversed both CB1R agonist and EtOH inhibition of adult neurogenesis. CB2R agonist HU-308 treatment did not produce any significant change in DCX + IR. Interestingly, neither EtOH nor CB1R agonist produced any alteration in cell proliferation in DG as measured by Ki67 + cell population, but CC3-positive cell numbers increased following EtOH or ACEA treatment suggesting an increase in cell death. CONCLUSIONS Together, these findings suggest that acute CB1R cannabinoid receptor activation and binge EtOH treatment reduce neurogenesis through mechanisms involving CB1R.
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Affiliation(s)
- Dal Khatri
- Neuroscience Research Program, Biomedical Biotechnology Research Institute, North Carolina Central University, Durham, North Carolina
| | - Genevieve Laroche
- Neuroscience Research Program, Biomedical Biotechnology Research Institute, North Carolina Central University, Durham, North Carolina
| | - Marion L Grant
- Department of Biology, North Carolina Central University, Durham, North Carolina
| | - Victoria M Jones
- Department of Chemistry & Biochemistry, North Carolina Central University, Durham, North Carolina
| | - Ryan P Vetreno
- Bowles Alcohol Research Center, UNC-Chapel Hill School of Medicine, Chapel Hill, North Carolina
| | - Fulton T Crews
- Bowles Alcohol Research Center, UNC-Chapel Hill School of Medicine, Chapel Hill, North Carolina.,Department of Pharmacology, UNC-Chapel Hill School of Medicine, Chapel Hill, North Carolina
| | - Somnath Mukhopadhyay
- Neuroscience Research Program, Biomedical Biotechnology Research Institute, North Carolina Central University, Durham, North Carolina.,Department of Chemistry & Biochemistry, North Carolina Central University, Durham, North Carolina.,Department of Pharmacology, UNC-Chapel Hill School of Medicine, Chapel Hill, North Carolina
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22
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Endocannabinoid modulation of dopamine neurotransmission. Neuropharmacology 2017; 124:52-61. [PMID: 28450060 DOI: 10.1016/j.neuropharm.2017.04.033] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 04/20/2017] [Accepted: 04/23/2017] [Indexed: 12/15/2022]
Abstract
Dopamine (DA) is a major catecholamine neurotransmitter in the mammalian brain that controls neural circuits involved in the cognitive, emotional, and motor aspects of goal-directed behavior. Accordingly, perturbations in DA neurotransmission play a central role in several neuropsychiatric disorders. Somewhat surprisingly given its prominent role in numerous behaviors, DA is released by a relatively small number of densely packed neurons originating in the midbrain. The dopaminergic midbrain innervates numerous brain regions where extracellular DA release and receptor binding promote short- and long-term changes in postsynaptic neuron function. Striatal forebrain nuclei receive the greatest proportion of DA projections and are a predominant hub at which DA influences behavior. A number of excitatory, inhibitory, and modulatory inputs orchestrate DA neurotransmission by controlling DA cell body firing patterns, terminal release, and effects on postsynaptic sites in the striatum. The endocannabinoid (eCB) system serves as an important filter of afferent input that acts locally at midbrain and terminal regions to shape how incoming information is conveyed onto DA neurons and to output targets. In this review, we aim to highlight existing knowledge regarding how eCB signaling controls DA neuron function through modifications in synaptic strength at midbrain and striatal sites, and to raise outstanding questions on this topic. This article is part of the Special Issue entitled "A New Dawn in Cannabinoid Neurobiology".
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Owens RA, Ignatowska-Jankowska B, Mustafa M, Beardsley PM, Wiley JL, Jali A, Selley DE, Niphakis MJ, Cravatt BF, Lichtman AH. Discriminative Stimulus Properties of the Endocannabinoid Catabolic Enzyme Inhibitor SA-57 in Mice. J Pharmacol Exp Ther 2016; 358:306-14. [PMID: 27307500 DOI: 10.1124/jpet.115.229492] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Accepted: 05/18/2016] [Indexed: 12/15/2022] Open
Abstract
Whereas the inhibition of fatty acid amide hydrolase (FAAH) or monoacylglycerol lipase (MAGL), the respective major hydrolytic enzymes of N-arachidonoyl ethanolamine (AEA) and 2-arachidonoylglycerol (2-AG), elicits no or partial substitution for Δ(9)-tetrahydrocannabinol (THC) in drug-discrimination procedures, combined inhibition of both enzymes fully substitutes for THC, as well as produces a constellation of cannabimimetic effects. The present study tested whether C57BL/6J mice would learn to discriminate the dual FAAH-MAGL inhibitor SA-57 (4-[2-(4-chlorophenyl)ethyl]-1-piperidinecarboxylic acid 2-(methylamino)-2-oxoethyl ester) from vehicle in the drug-discrimination paradigm. In initial experiments, 10 mg/kg SA-57 fully substituted for CP55,940 ((-)-cis-3-[2-hydroxy-4-(1,1-dimethylheptyl)phenyl]-trans-4-(3-hydroxypropyl)cyclohexanol), a high-efficacy CB1 receptor agonist in C57BL/6J mice and for AEA in FAAH (-/-) mice. Most (i.e., 23 of 24) subjects achieved criteria for discriminating SA-57 (10 mg/kg) from vehicle within 40 sessions, with full generalization occurring 1 to 2 hours postinjection. CP55,940, the dual FAAH-MAGL inhibitor JZL195 (4-nitrophenyl 4-(3-phenoxybenzyl)piperazine-1-carboxylate), and the MAGL inhibitors MJN110 (2,5-dioxopyrrolidin-1-yl 4-(bis(4-chlorophenyl)methyl)piperazine-1-carboxylate) and JZL184 (4-[Bis(1,3-benzodioxol-5-yl)hydroxymethyl]-1-piperidinecarboxylic acid 4-nitrophenyl ester) fully substituted for SA-57. Although the FAAH inhibitors PF-3845 ((N-3-pyridinyl-4-[[3-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenyl]methyl]-1-piperidinecarboxamide) and URB597 (cyclohexylcarbamic acid 3'-(aminocarbonyl)-[1,1'-biphenyl]-3-yl ester) did not substitute for SA-57, PF-3845 produced a 2-fold leftward shift in the MJN110 substitution dose-response curve. In addition, the CB1 receptor antagonist rimonabant blocked the generalization of SA-57, as well as substitution of CP55,940, JZL195, MJN110, and JZL184. These findings suggest that MAGL inhibition plays a major role in the CB1 receptor-mediated SA-57 training dose, which is further augmented by FAAH inhibition.
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Affiliation(s)
- Robert A Owens
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia (R.A.O., B.I.J., M.M., P.M.B., A.J., D.E.S., A.H.L.); RTI International, Research Triangle Park, North Carolina (J.L.W.); and The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N.; B.F.C.)
| | - Bogna Ignatowska-Jankowska
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia (R.A.O., B.I.J., M.M., P.M.B., A.J., D.E.S., A.H.L.); RTI International, Research Triangle Park, North Carolina (J.L.W.); and The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N.; B.F.C.)
| | - Mohammed Mustafa
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia (R.A.O., B.I.J., M.M., P.M.B., A.J., D.E.S., A.H.L.); RTI International, Research Triangle Park, North Carolina (J.L.W.); and The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N.; B.F.C.)
| | - Patrick M Beardsley
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia (R.A.O., B.I.J., M.M., P.M.B., A.J., D.E.S., A.H.L.); RTI International, Research Triangle Park, North Carolina (J.L.W.); and The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N.; B.F.C.)
| | - Jenny L Wiley
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia (R.A.O., B.I.J., M.M., P.M.B., A.J., D.E.S., A.H.L.); RTI International, Research Triangle Park, North Carolina (J.L.W.); and The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N.; B.F.C.)
| | - Abdulmajeed Jali
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia (R.A.O., B.I.J., M.M., P.M.B., A.J., D.E.S., A.H.L.); RTI International, Research Triangle Park, North Carolina (J.L.W.); and The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N.; B.F.C.)
| | - Dana E Selley
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia (R.A.O., B.I.J., M.M., P.M.B., A.J., D.E.S., A.H.L.); RTI International, Research Triangle Park, North Carolina (J.L.W.); and The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N.; B.F.C.)
| | - Micah J Niphakis
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia (R.A.O., B.I.J., M.M., P.M.B., A.J., D.E.S., A.H.L.); RTI International, Research Triangle Park, North Carolina (J.L.W.); and The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N.; B.F.C.)
| | - Benjamin F Cravatt
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia (R.A.O., B.I.J., M.M., P.M.B., A.J., D.E.S., A.H.L.); RTI International, Research Triangle Park, North Carolina (J.L.W.); and The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N.; B.F.C.)
| | - Aron H Lichtman
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia (R.A.O., B.I.J., M.M., P.M.B., A.J., D.E.S., A.H.L.); RTI International, Research Triangle Park, North Carolina (J.L.W.); and The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N.; B.F.C.)
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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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Lazenka MF, Blough BE, Negus SS. Preclinical Abuse Potential Assessment of Flibanserin: Effects on Intracranial Self-Stimulation in Female and Male Rats. J Sex Med 2016; 13:338-49. [PMID: 26831817 PMCID: PMC4779698 DOI: 10.1016/j.jsxm.2015.12.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 11/30/2015] [Accepted: 12/24/2015] [Indexed: 10/22/2022]
Abstract
INTRODUCTION Flibanserin is a serotonin receptor subtype 1A agonist and 2A antagonist that has been approved by the Food and Drug Administration for treating female sexual interest and arousal disorder. Little is known about the abuse potential of flibanserin. AIM To examine abuse-related effects of flibanserin in rats using an intracranial self-stimulation (ICSS) procedure previously used to evaluate the abuse potential of other drugs. METHODS Adult female and male Sprague-Dawley rats with electrodes implanted in the medial forebrain bundle were trained to press a lever for electrical brain stimulation under a "frequency-rate" ICSS procedure. In this procedure, increasing frequencies of brain stimulation maintain increasing rates of responding. Drugs of abuse typically increase (or "facilitate") ICSS rates and produce leftward and upward shifts in ICSS frequency-rate curves, whereas drugs that lack abuse potential typically do not alter or only decrease ICSS rates. Initial studies determined the potency and time course of effects on ICSS produced by acute flibanserin administration (1.0, 3.2 and 10.0 mg/kg). Subsequent studies determined the effects of flibanserin (3.2-18 mg/kg) before and after a regimen of repeated flibanserin administration (5.6 mg/kg/d for 5 days). Effects of the abused stimulant amphetamine (1.0 mg/kg) were examined as a positive control. MAIN OUTCOME MEASURES Flibanserin effects on ICSS frequency-rate curves in female and male rats were examined and compared with the effects of amphetamine. RESULTS Baseline ICSS frequency-rate curves were similar in female and male rats. Acute and repeated administrations of flibanserin produced only decreases in ICSS rates, and rate-decreasing effects of the highest flibanserin dose (10 mg/kg) were greater in female than in male rats. In contrast to flibanserin, amphetamine produced an abuse-related increase in ICSS rates that did not differ between female and male rats. CONCLUSION These results suggest that flibanserin has low abuse potential. In addition, this study suggests that female rats might be more sensitive than male rats to the rate-decreasing effects of high flibanserin doses.
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Affiliation(s)
- Matthew F Lazenka
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA, USA.
| | - Bruce E Blough
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, NC, USA
| | - S Stevens Negus
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA, USA
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Molecular Mechanisms of Cannabis Signaling in the Brain. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 137:123-47. [PMID: 26810000 DOI: 10.1016/bs.pmbts.2015.10.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Cannabis has been cultivated and used by humans for thousands of years. Research for decades was focused on understanding the mechanisms of an illegal/addictive drug. This led to the discovery of the vast endocannabinoid system. Research has now shifted to understanding fundamental biological questions related to one of the most widespread signaling systems in both the brain and the body. Our understanding of cannabinoid signaling has advanced significantly in the last two decades. In this review, we discuss the state of knowledge on mechanisms of Cannabis signaling in the brain and the modulation of key brain neurotransmitter systems involved in both brain reward/addiction and psychiatric disorders. It is highly probable that various cannabinoids will be found to be efficacious in the treatment of a number of psychiatric disorders. However, while there is clearly much potential, marijuana has not been properly vetted by the medical-scientific evaluation process and there are clearly a range of potentially adverse side-effects-including addiction. We are at crossroads for research on endocannabinoid function and therapeutics (including the use of exogenous treatments such as Cannabis). With over 100 cannabinoid constituents, the majority of which have not been studied, there is much Cannabis research yet to be done. With more states legalizing both the medicinal and recreational use of marijuana the rigorous scientific investigation into cannabinoid signaling is imperative.
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Wiebelhaus JM, Walentiny DM, Beardsley PM. Effects of Acute and Repeated Administration of Oxycodone and Naloxone-Precipitated Withdrawal on Intracranial Self-Stimulation in Rats. J Pharmacol Exp Ther 2015; 356:43-52. [PMID: 26491062 DOI: 10.1124/jpet.115.228940] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 10/20/2015] [Indexed: 01/24/2023] Open
Abstract
Incidence of prescription opioid abuse and overdose, often led by oxycodone, continues to increase, producing twice as many overdose deaths as heroin. Surprisingly, preclinical reports relevant to oxycodone's abuse-related effects are relatively sparse considering its history and patient usage. The goal of this study was to characterize dose- and time-dependent effects of acute and repeated oxycodone administration in a frequency-rate intracranial self-stimulation (ICSS) procedure, an assay often predictive of drug-related reinforcing effects, in male Sprague-Dawley rats. We hypothesized that oxycodone would produce a biphasic profile of rate-increasing and rate-decreasing effects maintained by ICSS similar to μ-opioid receptor agonists. Oxycodone (0.03, 0.3, 1, and 3 mg/kg, s.c.) produced dose- and time-dependent alterations on ICSS, with the predicted biphasic profile of rate-increasing effects at lower stimulation frequencies followed by rate-decreasing effects at higher frequencies. Peak effects were observed between 30 and 60 minutes, which were reversed by naloxone pretreatment (30 minutes). Tolerance to rate-decreasing effects was observed over a 5-day period when rats were treated with 1 mg/kg oxycodone twice a day. Subsequently, the dosing regimen was increased to 3 mg/kg twice a day over 10 days, although further marked tolerance did not develop. When then challenged with 10 mg/kg naloxone, a significant suppression below baseline levels of ICSS-maintained responding occurred indicative of dependence that recovered to baseline within 5 hours. The results of this study provide the first report of acute and chronic effects of oxycodone on responding maintained by ICSS presentation and the use of ICSS-maintained responding to characterize its tolerance and dependence effects.
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Affiliation(s)
- Jason M Wiebelhaus
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - D Matthew Walentiny
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - Patrick M Beardsley
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
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Korpi ER, den Hollander B, Farooq U, Vashchinkina E, Rajkumar R, Nutt DJ, Hyytiä P, Dawe GS. Mechanisms of Action and Persistent Neuroplasticity by Drugs of Abuse. Pharmacol Rev 2015; 67:872-1004. [DOI: 10.1124/pr.115.010967] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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Lazenka MF, Tomarchio AJ, Lichtman AH, Greengard P, Flajolet M, Selley DE, Sim-Selley LJ. Role of Dopamine Type 1 Receptors and Dopamine- and cAMP-Regulated Phosphoprotein Mr 32 kDa in Δ9-Tetrahydrocannabinol-Mediated Induction of ΔFosB in the Mouse Forebrain. J Pharmacol Exp Ther 2015; 354:316-27. [PMID: 26099530 DOI: 10.1124/jpet.115.224428] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 06/18/2015] [Indexed: 11/22/2022] Open
Abstract
Δ(9)-Tetrahydrocannabinol (THC), the main psychoactive component of marijuana, produces motor and motivational effects via interactions with the dopaminergic system in the caudate-putamen and nucleus accumbens. However, the molecular events that underlie these interactions after THC treatment are not well understood. Our study shows that pretreatment with dopamine D1 receptor (D1R) antagonists before repeated administration of THC attenuated induction of Δ FBJ murine osteosarcoma viral oncogene homolog B (ΔFosB) in the nucleus accumbens, caudate-putamen, amygdala, and prefrontal cortex. Anatomical studies showed that repeated THC administration induced ΔFosB in D1R-containing striatal neurons. Dopamine signaling in the striatum involves phosphorylation-specific effects of the dopamine- and cAMP-regulated phosphoprotein Mr 32 kDa (DARPP-32), which regulates protein kinase A signaling. Genetic deletion of DARPP-32 attenuated ΔFosB expression measured after acute, but not repeated, THC administration in both the caudate-putamen and nucleus accumbens. THC was then acutely or repeatedly administered to wild-type (WT) and DARPP-32 knockout (KO) mice, and in vivo responses were measured. DARPP-32 KO mice exhibited enhanced acute THC-mediated hypolocomotion and developed greater tolerance to this response relative to the WT mice. Agonist-stimulated guanosine 5'-O-(3-[(35)S]thio)triphosphate ([(35)S]GTPγS) binding showed that cannabinoid-stimulated G-protein activity did not differ between DARPP-32 KO and WT mice treated with vehicle or repeated THC. These results indicate that D1Rs play a major role in THC-mediated ΔFosB induction in the forebrain, whereas the role of DARPP-32 in THC-mediated ΔFosB induction and modulation of motor activity appears to be more complex.
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Affiliation(s)
- Matthew F Lazenka
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, Virginia (M.F.L., A.J.T., A.H.L., D.E.S., L.J.S.-S.); and Laboratory of Molecular and Cellular Neuroscience, Rockefeller University, New York, New York (P.G., M.F.)
| | - Aaron J Tomarchio
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, Virginia (M.F.L., A.J.T., A.H.L., D.E.S., L.J.S.-S.); and Laboratory of Molecular and Cellular Neuroscience, Rockefeller University, New York, New York (P.G., M.F.)
| | - Aron H Lichtman
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, Virginia (M.F.L., A.J.T., A.H.L., D.E.S., L.J.S.-S.); and Laboratory of Molecular and Cellular Neuroscience, Rockefeller University, New York, New York (P.G., M.F.)
| | - Paul Greengard
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, Virginia (M.F.L., A.J.T., A.H.L., D.E.S., L.J.S.-S.); and Laboratory of Molecular and Cellular Neuroscience, Rockefeller University, New York, New York (P.G., M.F.)
| | - Marc Flajolet
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, Virginia (M.F.L., A.J.T., A.H.L., D.E.S., L.J.S.-S.); and Laboratory of Molecular and Cellular Neuroscience, Rockefeller University, New York, New York (P.G., M.F.)
| | - Dana E Selley
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, Virginia (M.F.L., A.J.T., A.H.L., D.E.S., L.J.S.-S.); and Laboratory of Molecular and Cellular Neuroscience, Rockefeller University, New York, New York (P.G., M.F.)
| | - Laura J Sim-Selley
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, Virginia (M.F.L., A.J.T., A.H.L., D.E.S., L.J.S.-S.); and Laboratory of Molecular and Cellular Neuroscience, Rockefeller University, New York, New York (P.G., M.F.)
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Grim TW, Wiebelhaus JM, Negus SS, Lichtman AH, Lichtman AH. Effects of acute and repeated dosing of the synthetic cannabinoid CP55,940 on intracranial self-stimulation in mice. Drug Alcohol Depend 2015; 150:31-7. [PMID: 25772438 PMCID: PMC4601922 DOI: 10.1016/j.drugalcdep.2015.01.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 01/19/2015] [Accepted: 01/21/2015] [Indexed: 01/19/2023]
Abstract
BACKGROUND Synthetic cannabinoids have emerged as a significant public health concern. To increase the knowledge of how these molecules interact on brain reward processes, we investigated the effects of CP55,940, a high efficacy synthetic CB1 receptor agonist, in a frequency-rate intracranial self-stimulation (ICSS) procedure. METHODS The impact of acute and repeated administration (seven days) of CP55,940 on operant responding for electrical brain stimulation of the medial forebrain bundle was investigated in C57BL/6J mice. RESULTS CP55,940 attenuated ICSS in a dose-related fashion (ED50 (95% C.L.)=0.15 (0.12-0.18)mg/kg). This effect was blocked by the CB1 receptor antagonist rimonabant. Tolerance developed quickly, though not completely, to the rate-decreasing effects of CP55,940 (0.3mg/kg). Abrupt discontinuation of drug did not alter baseline responding for up to seven days. Moreover, rimonabant (10mg/kg) challenge did not alter ICSS responding in mice treated repeatedly with CP55,940. CONCLUSIONS The finding that CP55,940 reduced ICSS in mice with no evidence of facilitation at any dose is consistent with synthetic cannabinoid effects on ICSS in rats. CP55,940-induced ICSS depression was mediated through a CB1 receptor mechanism. Additionally, tolerance and dependence following repeated CP55,940 administration were dissociable. Thus, CP55,940 does not produce reward-like effects in ICSS under these conditions.
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Affiliation(s)
| | | | | | | | - Aron H Lichtman
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, PO Box 980613, Richmond, 23298-0613, VA U.S.A
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Hruba L, Seillier A, Zaki A, Cravatt BF, Lichtman AH, Giuffrida A, McMahon LR. Simultaneous inhibition of fatty acid amide hydrolase and monoacylglycerol lipase shares discriminative stimulus effects with Δ9-tetrahydrocannabinol in mice. J Pharmacol Exp Ther 2015; 353:261-8. [PMID: 25711338 DOI: 10.1124/jpet.115.222836] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH) inhibitors exert preclinical effects indicative of therapeutic potential (i.e., analgesia). However, the extent to which MAGL and FAAH inhibitors produce unwanted effects remains unclear. Here, FAAH and MAGL inhibition was examined separately and together in a Δ(9)-tetrahydrocannabinol (Δ(9)-THC; 5.6 mg/kg i.p.) discrimination assay predictive of subjective effects associated with cannabis use, and the relative contribution of N-arachidonoyl ethanolamine (AEA) and 2-arachidonoylglycerol (2-AG) in the prefrontal cortex, hippocampus, and caudate putamen to those effects was examined. Δ(9)-THC dose-dependently increased Δ(9)-THC appropriate responses (ED50 value = 2.8 mg/kg), whereas the FAAH inhibitors PF-3845 [N-3-pyridinyl-4-[[3-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenyl]methyl]-1-piperidinecarboxamide] and URB597 [(3'-(aminocarbonyl)[1,1'-biphenyl]-3-yl)-cyclohexylcarbamate] or a MAGL inhibitor JZL184 [4-nitrophenyl-4-(dibenzo[d][1,3]dioxol-5-yl(hydroxy)methyl)piperidine-1-carboxylate] alone did not substitute for the Δ(9)-THC discriminative stimulus. The nonselective FAAH/MAGL inhibitors SA-57 [4-[2-(4-chlorophenyl)ethyl]-1-piperidinecarboxylic acid 2-(methylamino)-2-oxoethyl ester] and JZL195 [4-nitrophenyl 4-(3-phenoxybenzyl)piperazine-1-carboxylate] fully substituted for Δ(9)-THC with ED50 values equal to 2.4 and 17 mg/kg, respectively. Full substitution for Δ(9)-THC was also produced by a combination of JZL184 and PF-3845, but not by a combination of JZL184 and URB597 (i.e., 52% maximum). Cannabinoid receptor type 1 antagonist rimonabant attenuated the discriminative stimulus effects of Δ(9)-THC, SA-57, JZL195, and the combined effects of JZL184 and PF-3845. Full substitution for the Δ(9)-THC discriminative stimulus occurred only when both 2-AG and AEA were significantly elevated, and the patterns of increased endocannabinoid content were similar among brain regions. Overall, these results suggest that increasing both endogenous 2-AG and AEA produces qualitatively unique effects (i.e., the subjective effects of cannabis) that are not obtained from increasing either 2-AG or AEA separately.
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Affiliation(s)
- Lenka Hruba
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, Texas (L.H., A.S., A.Z., A.G., L.R.M.); Department of Chemical Physiology, Skaggs Institute for Chemical Biology, Scripps Research Institute, La Jolla, California (B.F.C.); and Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia (A.H.L.)
| | - Alexandre Seillier
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, Texas (L.H., A.S., A.Z., A.G., L.R.M.); Department of Chemical Physiology, Skaggs Institute for Chemical Biology, Scripps Research Institute, La Jolla, California (B.F.C.); and Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia (A.H.L.)
| | - Armia Zaki
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, Texas (L.H., A.S., A.Z., A.G., L.R.M.); Department of Chemical Physiology, Skaggs Institute for Chemical Biology, Scripps Research Institute, La Jolla, California (B.F.C.); and Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia (A.H.L.)
| | - Benjamin F Cravatt
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, Texas (L.H., A.S., A.Z., A.G., L.R.M.); Department of Chemical Physiology, Skaggs Institute for Chemical Biology, Scripps Research Institute, La Jolla, California (B.F.C.); and Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia (A.H.L.)
| | - Aron H Lichtman
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, Texas (L.H., A.S., A.Z., A.G., L.R.M.); Department of Chemical Physiology, Skaggs Institute for Chemical Biology, Scripps Research Institute, La Jolla, California (B.F.C.); and Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia (A.H.L.)
| | - Andrea Giuffrida
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, Texas (L.H., A.S., A.Z., A.G., L.R.M.); Department of Chemical Physiology, Skaggs Institute for Chemical Biology, Scripps Research Institute, La Jolla, California (B.F.C.); and Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia (A.H.L.)
| | - Lance R McMahon
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, Texas (L.H., A.S., A.Z., A.G., L.R.M.); Department of Chemical Physiology, Skaggs Institute for Chemical Biology, Scripps Research Institute, La Jolla, California (B.F.C.); and Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia (A.H.L.)
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