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Chang NHS, Kumakura Y, Møller A, Linnet J, Bender D, Doudet DJ, Vafaee MS, Gjedde A. On the learning of addictive behavior: Sensation-seeking propensity predicts dopamine turnover in dorsal striatum. Brain Imaging Behav 2021; 16:355-365. [PMID: 34417966 PMCID: PMC8825434 DOI: 10.1007/s11682-021-00509-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/14/2021] [Indexed: 11/26/2022]
Abstract
We asked if sensation-seeking is linked to premorbid personality characteristics in patients with addictive disorders, or the characteristics follow the sensation-seeking activity. We interpreted the former as a state associated with normal rates of dopamine synthesis, and the latter as a trait of individuals with abnormally high rates of synthesis. We previously determined dopaminergic receptor density in striatum, and we now tested the hypothesis that an elevated dopaminergic condition with increased extracellular dopamine and receptor density follows increased dopamine synthesis capacity in highly sensation-seeking individuals, as measured by positron emission tomography of 18 men with tracer fluorodopa (FDOPA). We detected a site in left caudate nucleus where the volume of distribution of FDOPA-derived metabolites correlated negatively with FDOPA metabolite turnover, consistent with decreased metabolite breakdown in highly sensation-seeking subjects. High rates of sensation-seeking attenuated the dopamine turnover in association with a low rate of dopamine recycling, low dopamine oxidation, and elevated extracellular dopamine and receptors in caudate nucleus. In contrast, low rates of sensation-seeking were associated with rapid dopamine recycling, rapid dopamine oxidation, low extracellular dopamine, and low receptor density. We conclude that the modulation of dopaminergic neurotransmission associated with sensation-seeking is a state of sensation-seeking, rather than a trait of personality following abnormal regulation of dopaminergic neurotransmission.
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Affiliation(s)
- Natalie Hong Siu Chang
- Department of Clinical Research, University of Southern Denmark, Odense C, DK-5000 Denmark
| | - Yoshitaka Kumakura
- Department of Diagnostic Radiology and Nuclear Medicine, Saitama Medical University, 1981 Kamoda, Kawagoe, Saitama 350-8550 Japan
| | - Arne Møller
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, DK-8200 Aarhus N, Denmark
| | - Jakob Linnet
- Gambling Disorder & BED Clinic, Department of Occupational and Environmental Medicine, Odense University Hospital, Odense C, Dk-5000 Denmark
| | - Dirk Bender
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, DK-8200 Aarhus N, Denmark
| | - Doris J. Doudet
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, DK-8200 Aarhus N, Denmark
- Department of Medicine, Division of Neurology, University of British Columbia, Vancouver, B.C. V6T 2B5 Canada
| | - Manouchehr Seyedi Vafaee
- Department of Clinical Research, BRIDGE, University of Southern Denmark, Odense M, DK-5230 Denmark
| | - Albert Gjedde
- Department of Neuroscience, University of Copenhagen, Copenhagen, DK-2200 Denmark
- Department of Clinical Medicine, University of Southern Denmark, Odense C, DK-5000 Denmark
- Translational Neuropsychiatry Unit, Aarhus University, Aarhus, DK-8000 Denmark
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Clark L, Boileau I, Zack M. Neuroimaging of reward mechanisms in Gambling disorder: an integrative review. Mol Psychiatry 2019; 24:674-693. [PMID: 30214041 DOI: 10.1038/s41380-018-0230-2] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 07/28/2018] [Accepted: 08/02/2018] [Indexed: 12/14/2022]
Abstract
Gambling disorder (GD) was reclassified as a behavioral addiction in the DSM-5 and shares clinical and behavioral features with substance use disorders (SUDs). Neuroimaging studies of GD hold promise in isolating core features of the addiction syndrome, avoiding confounding effects of drug neurotoxicity. At the same time, a neurobiologically-grounded theory of how behaviors like gambling can become addictive remains lacking, posing a significant hurdle for ongoing decisions in addiction nosology. This article integrates research on reward-related brain activity (functional MRI) and neurotransmitter function (PET) in GD, alongside the consideration of structural MRI data as to whether these signals more likely reflect pre-existing vulnerability or neuroadaptive change. Where possible, we point to qualitative similarities and differences with established markers for SUDs. Structural MRI studies indicate modest changes in regional gray matter volume and diffuse reductions in white matter integrity in GD, contrasting with clear structural deterioration in SUDs. Functional MRI studies consistently identify dysregulation in reward-related circuitry (primarily ventral striatum and medial prefrontal cortex), but evidence is mixed as to the direction of these effects. The need for further parsing of reward sub-processes is emphasized, including anticipation vs outcome, gains vs. losses, and disorder-relevant cues vs natural rewards. Neurotransmitter PET studies indicate amplified dopamine (DA) release in GD, in the context of minimal differences in baseline DA D2 receptor binding, highlighting a distinct profile from SUDs. Preliminary work has investigated further contributions of opioids, GABA and serotonin. Neuroimaging data increasingly highlight divergent profiles in GD vs. SUDs. The ability of gambling to perpetually activate DA (via maximal uncertainty) may contribute to neuroimaging similarities between GD and SUDs, whereas the supra-physiological DA effects of drugs may partly explain differences in the neuroimaging profile of the two syndromes. Coupled with consistent observations of correlations with gambling severity and related clinical variables within GD samples, the overall pattern of effects is interpreted as a likely combination of shared vulnerability markers across GD and SUDs, but with further experience-dependent neuroadaptive processes in GD.
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Affiliation(s)
- Luke Clark
- Centre for Gambling Research, University of British Columbia (UBC), Vancouver, BC, Canada.,Department of Psychology, University of British Columbia, Vancouver, BC, Canada
| | - Isabelle Boileau
- Addiction Imaging Research Group, Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada.,Vivian M. Rakoff PET Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Addictions Program, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Schizophrenia Program, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Martin Zack
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada. .,Clinical Neuroscience Program, Centre for Addiction and Mental Health, Toronto, ON, Canada. .,Department of Pharmacology & Toxicology, University of Toronto, Toronto, ON, Canada. .,Department of Public Health Sciences, University of Toronto, Toronto, ON, Canada.
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3
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Jauhar S, Veronese M, Rogdaki M, Bloomfield M, Natesan S, Turkheimer F, Kapur S, Howes OD. Regulation of dopaminergic function: an [ 18F]-DOPA PET apomorphine challenge study in humans. Transl Psychiatry 2017; 7:e1027. [PMID: 28170002 PMCID: PMC5438020 DOI: 10.1038/tp.2016.270] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 07/25/2016] [Accepted: 08/02/2016] [Indexed: 02/08/2023] Open
Abstract
Dopaminergic function has a key role in normal brain function, dopaminergic dysfunction being implicated in numerous neuropsychiatric disorders. Animal studies show that dopaminergic stimulation regulates dopaminergic function, but it is not known whether this exists in humans. In the first study (study 1), we measured dopamine synthesis capacity (indexed as Kicer) to identify the relationship between baseline and change in Kicer under resting conditions for comparison with effects of dopaminergic stimulation. In the second study (study 2), we used a within-subjects design to test effects of dopaminergic stimulation on dopamine synthesis capacity. In study 1, eight volunteers received two 18F-DOPA scans on separate days, both at rest. In study 2, 12 healthy male volunteers received two 18F-DOPA positron emission tomographic (PET) scans after treatment with either the dopamine partial agonist apomorphine (0.03 or 0.005 mg kg-1) or placebo. In study 1, no significant correlation was found between baseline and change in dopamine synthesis capacity between scans (r=-0.57, n=8, P=0.17, two-tailed). In study 2, a significant negative correlation was found between baseline dopamine synthesis capacity and percentage change in dopamine synthesis capacity after apomorphine challenge (r=-0.71, n=12, P=0.01, two-tailed). This correlation was significantly different (P<0.01) from the correlation between baseline and change in dopamine synthesis capacity under unstimulated conditions. One-way repeated-measures analysis of variance showed a significant group (study 1/study 2) × time interaction (F(1,18)=11.5, P=0.003). Our findings suggest that regulation of dopamine synthesis capacity by apomorphine depends on baseline dopamine function, consistent with dopamine stimulation stabilizing dopaminergic function. Loss of this autoregulation may contribute to dopaminergic dysfunction in brain disorders such as schizophrenia, substance dependence, and Parkinson's disease.
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Affiliation(s)
- S Jauhar
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College, London, UK
| | - M Veronese
- Centre for Neuroimaging Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College, London, UK
| | - M Rogdaki
- MRC London Institute of Medical Sciences, London, UK
| | - M Bloomfield
- MRC London Institute of Medical Sciences, London, UK
| | - S Natesan
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College, London, UK
| | - F Turkheimer
- Centre for Neuroimaging Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College, London, UK
| | - S Kapur
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College, London, UK
| | - O D Howes
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College, London, UK
- MRC London Institute of Medical Sciences, London, UK
- Institute of Clinical Sciences, Department of Medicine, Imperial College London, London, UK
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4
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Volkow ND, Wiers CE, Shokri-Kojori E, Tomasi D, Wang GJ, Baler R. Neurochemical and metabolic effects of acute and chronic alcohol in the human brain: Studies with positron emission tomography. Neuropharmacology 2017; 122:175-188. [PMID: 28108358 DOI: 10.1016/j.neuropharm.2017.01.012] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 12/20/2016] [Accepted: 01/14/2017] [Indexed: 02/07/2023]
Abstract
The use of Positron emission tomography (PET) to study the effects of acute and chronic alcohol on the human brain has enhanced our understanding of the mechanisms underlying alcohol's rewarding effects, the neuroadaptations from chronic exposure that contribute to tolerance and withdrawal, and the changes in fronto-striatal circuits that lead to loss of control and enhanced motivation to drink that characterize alcohol use disorders (AUD). These include studies showing that alcohol's reinforcing effects may result not only from its enhancement of dopaminergic, GABAergic and opioid signaling but also from its caloric properties. Studies in those suffering from an AUD have revealed significant alterations in dopamine (DA), GABA, cannabinoids, opioid and serotonin neurotransmission and in brain energy utilization (glucose and acetate metabolism) that are likely to contribute to compulsive alcohol taking, dysphoria/depression, and to alcohol-associated neurotoxicity. Studies have also evaluated the effects of abstinence on recovery of brain metabolism and neurotransmitter function and the potential value of some of these measures to predict clinical outcomes. Finally, PET studies have started to provide insights about the neuronal mechanisms by which certain genes contribute to the vulnerability to AUD. These findings have helped identify new strategies for prevention and treatment of AUD. This article is part of the Special Issue entitled "Alcoholism".
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Affiliation(s)
- Nora D Volkow
- National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD 20892, United States; National Institute on Alcohol Abuse and Alcoholism, Laboratory of Neuroimaging, National Institutes of Health, Bethesda, MD 20892, United States.
| | - Corinde E Wiers
- National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD 20892, United States
| | - Ehsan Shokri-Kojori
- National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD 20892, United States
| | - Dardo Tomasi
- National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD 20892, United States
| | - Gene-Jack Wang
- National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD 20892, United States
| | - Ruben Baler
- National Institute on Alcohol Abuse and Alcoholism, Laboratory of Neuroimaging, National Institutes of Health, Bethesda, MD 20892, United States
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Common Variation in the DOPA Decarboxylase (DDC) Gene and Human Striatal DDC Activity In Vivo. Neuropsychopharmacology 2016; 41:2303-8. [PMID: 26924680 PMCID: PMC4946061 DOI: 10.1038/npp.2016.31] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 01/26/2016] [Accepted: 01/26/2016] [Indexed: 12/24/2022]
Abstract
The synthesis of multiple amine neurotransmitters, such as dopamine, norepinephrine, serotonin, and trace amines, relies in part on DOPA decarboxylase (DDC, AADC), an enzyme that is required for normative neural operations. Because rare, loss-of-function mutations in the DDC gene result in severe enzymatic deficiency and devastating autonomic, motor, and cognitive impairment, DDC common genetic polymorphisms have been proposed as a source of more moderate, but clinically important, alterations in DDC function that may contribute to risk, course, or treatment response in complex, heritable neuropsychiatric illnesses. However, a direct link between common genetic variation in DDC and DDC activity in the living human brain has never been established. We therefore tested for this association by conducting extensive genotyping across the DDC gene in a large cohort of 120 healthy individuals, for whom DDC activity was then quantified with [(18)F]-FDOPA positron emission tomography (PET). The specific uptake constant, Ki, a measure of DDC activity, was estimated for striatal regions of interest and found to be predicted by one of five tested haplotypes, particularly in the ventral striatum. These data provide evidence for cis-acting, functional common polymorphisms in the DDC gene and support future work to determine whether such variation might meaningfully contribute to DDC-mediated neural processes relevant to neuropsychiatric illness and treatment.
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Rademacher L, Prinz S, Winz O, Henkel K, Dietrich CA, Schmaljohann J, Mohammadkhani Shali S, Schabram I, Stoppe C, Cumming P, Hilgers RD, Kumakura Y, Coburn M, Mottaghy FM, Gründer G, Vernaleken I. Effects of Smoking Cessation on Presynaptic Dopamine Function of Addicted Male Smokers. Biol Psychiatry 2016; 80:198-206. [PMID: 26803340 DOI: 10.1016/j.biopsych.2015.11.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 10/25/2015] [Accepted: 11/11/2015] [Indexed: 10/22/2022]
Abstract
BACKGROUND There is evidence of abnormal cerebral dopamine transmission in nicotine-dependent smokers, but it is unclear whether dopaminergic abnormalities are due to acute nicotine abuse or whether they persist with abstinence. We addressed this question by conducting longitudinal positron emission tomography (PET) examination of smokers before and after 3 months of abstinence. METHODS We obtained baseline 6-[(18)F]fluoro-L-DOPA (FDOPA)-PET scans in 15 nonsmokers and 30 nicotine-dependent smokers, who either smoked as per their usual habit or were in acute withdrawal. All smokers then underwent cessation treatment, and successful abstainers were re-examined by FDOPA-PET after 3 months of abstinence (n = 15). Uptake of FDOPA was analyzed using a steady-state model yielding estimates of the dopamine synthesis capacity (K); the turnover of tracer dopamine formed in living brain (kloss); and the tracer distribution volume (Vd), which is an index of dopamine storage capacity. RESULTS Compared with nonsmokers, K was 15% to 20% lower in the caudate nuclei of consuming smokers. Intraindividual comparisons of consumption and long-term abstinence revealed significant increases in K in the right dorsal and left ventral caudate nuclei. Relative to acute withdrawal, Vd significantly decreased in the right ventral and dorsal caudate after prolonged abstinence. Severity of nicotine dependence significantly correlated with dopamine synthesis capacity and dopamine turnover in the bilateral ventral putamen of consuming smokers. CONCLUSIONS The results suggest a lower dopamine synthesis capacity in nicotine-dependent smokers that appears to normalize with abstinence. Further investigations are needed to clarify the role of dopamine in nicotine addiction to help develop smoking prevention and cessation treatments.
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Affiliation(s)
- Lena Rademacher
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen; Department of Psychiatry and Psychotherapy, Social Neuroscience Laboratory, University of Lübeck, Lübeck, Germany.
| | - Susanne Prinz
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen; Department of Psychiatry and Psychotherapy, Centre for Integrative Psychiatry, University of Zürich, Rheinau, Switzerland
| | - Oliver Winz
- Department of Nuclear Medicine, RWTH Aachen University, Aachen
| | - Karsten Henkel
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen
| | - Claudia A Dietrich
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen
| | | | | | - Ina Schabram
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen
| | - Christian Stoppe
- Department of Anesthesiology, RWTH Aachen University, Aachen; Institute of Biochemistry and Molecular Cell Biology, RWTH Aachen University, Aachen
| | - Paul Cumming
- Department of Neuropsychiatry and Psychosomatic Medicine, Oslo University Hospital, Oslo, Norway; School of Psychology and Counselling, Queensland University of Technology, Brisbane, Queensland, Australia
| | | | - Yoshitaka Kumakura
- Department of Pharmacology and Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Mark Coburn
- Department of Anesthesiology, RWTH Aachen University, Aachen
| | - Felix M Mottaghy
- Department of Nuclear Medicine, RWTH Aachen University, Aachen; Jülich/Aachen Research Alliance, Aachen, Germany; Department of Nuclear Medicine, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Gerhard Gründer
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen; Jülich/Aachen Research Alliance, Aachen, Germany
| | - Ingo Vernaleken
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen; Jülich/Aachen Research Alliance, Aachen, Germany
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Feltmann K, Fredriksson I, Wirf M, Schilström B, Steensland P. The monoamine stabilizer (-)-OSU6162 counteracts downregulated dopamine output in the nucleus accumbens of long-term drinking Wistar rats. Addict Biol 2016; 21:438-49. [PMID: 26464265 PMCID: PMC5057338 DOI: 10.1111/adb.12304] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 08/09/2015] [Accepted: 08/14/2015] [Indexed: 11/29/2022]
Abstract
We recently established that the monoamine stabilizer (−)‐OSU6162 (OSU6162) decreased voluntary alcohol‐mediated behaviors, including alcohol intake and cue/priming‐induced reinstatement, in long‐term drinking rats, while blunting alcohol‐induced dopamine output in the nucleus accumbens (NAc) of alcohol‐naïve rats. Therefore, we hypothesized that OSU6162 attenuates alcohol‐mediated behaviors by blunting alcohol's rewarding effects. Here, we evaluated the effects of long‐term drinking and OSU6162 treatment (30 mg/kg, sc) on basal and alcohol‐induced (2.5 g/kg, ip) NAc dopamine outputs in Wistar rats after 10 months of intermittent access to 20% alcohol. The results showed that basal and alcohol‐induced NAc dopamine outputs were significantly lower in long‐term drinking rats, compared with alcohol‐naïve rats. In the long‐term drinking rats, OSU6162 slowly increased and maintained the dopamine output significantly elevated compared with baseline for at least 4 hours. Furthermore, OSU6162 pre‐treatment did not blunt the alcohol‐induced output in the long‐term drinking rats, a finding that contrasted with our previous results in alcohol‐naïve rats. Finally, OSU6162 did not induce conditioned place preference (CPP) in either long‐term drinking or alcohol‐naïve rats, indicating that OSU6162 has no reinforcing properties. To verify that the CPP results were not due to memory acquisition impairment, we demonstrated that OSU6162 did not affect novel object recognition. In conclusion, these results indicate that OSU6162 attenuates alcohol‐mediated behaviors by counteracting NAc dopamine deficits in long‐term drinking rats and that OSU6162 is not rewarding on its own. Together with OSU6162's beneficial side‐effect profile, the present study merits evaluation of OSU6162's clinical efficacy to attenuate alcohol use in alcohol‐dependent patients.
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Affiliation(s)
- Kristin Feltmann
- Department of Clinical Neuroscience Karolinska Institutet Solna Stockholm Sweden
| | - Ida Fredriksson
- Department of Clinical Neuroscience Karolinska Institutet Solna Stockholm Sweden
| | - Malin Wirf
- Department of Clinical Neuroscience Karolinska Institutet Solna Stockholm Sweden
| | - Björn Schilström
- Sahlgrenska Academy University of Gothenburg Gothenburg Sweden
- Department of Physiology and Pharmacology Karolinska Institutet Solna Stockholm Sweden
| | - Pia Steensland
- Department of Clinical Neuroscience Karolinska Institutet Solna Stockholm Sweden
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Wiers CE, Cabrera E, Skarda E, Volkow ND, Wang GJ. PET imaging for addiction medicine: From neural mechanisms to clinical considerations. PROGRESS IN BRAIN RESEARCH 2015; 224:175-201. [PMID: 26822359 DOI: 10.1016/bs.pbr.2015.07.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Positron emission tomography (PET) has been shown to be an effective imaging technique to study neurometabolic and neurochemical processes involved in addiction. That is, PET has been used to research neurobiological differences in substance abusers versus healthy controls and the pharmacokinetics and pharmacodynamics of abused drugs. Over the past years, the research scope has shifted to investigating neurobiological effects of abstinence and treatment, and their predictive power for relapse and other clinical outcomes. This chapter provides an overview of PET methodology, recent human PET studies on drug addiction and their implications for clinical treatment.
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Affiliation(s)
- Corinde E Wiers
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA.
| | - Elizabeth Cabrera
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Emily Skarda
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Nora D Volkow
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA; National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD, USA
| | - Gene-Jack Wang
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
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Hillmer AT, Mason GF, Fucito LM, O'Malley SS, Cosgrove KP. How Imaging Glutamate, γ-Aminobutyric Acid, and Dopamine Can Inform the Clinical Treatment of Alcohol Dependence and Withdrawal. Alcohol Clin Exp Res 2015; 39:2268-82. [PMID: 26510169 DOI: 10.1111/acer.12893] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 08/29/2015] [Indexed: 12/29/2022]
Abstract
Neuroimaging studies have dramatically advanced our understanding of the neurochemical basis of alcohol dependence, a major public health issue. In this paper, we review the research generated from neurochemical specific imaging modalities including magnetic resonance spectroscopy, positron emission tomography, and single-photon emission computed tomography in studies of alcohol dependence and withdrawal. We focus on studies interrogating γ-aminobutyric acid (GABA), glutamate, and dopamine, as these are prominent neurotransmitter systems implicated in alcohol dependence. Highlighted findings include diminished dopaminergic functioning and modulation of the GABA system by tobacco smoking during alcohol withdrawal. Then, we consider how these findings impact the clinical treatment of alcohol dependence and discuss directions for future experiments to address existing gaps in the literature, for example, sex differences and smoking comorbidity. These and other considerations provide opportunities to build upon the current neurochemistry imaging literature of alcohol dependence and withdrawal, which may usher in improved therapeutic and relapse prevention strategies.
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Affiliation(s)
- Ansel T Hillmer
- Departments of Psychiatry and Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut
| | - Graeme F Mason
- Departments of Psychiatry and Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut
| | - Lisa M Fucito
- Departments of Psychiatry and Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut
| | - Stephanie S O'Malley
- Departments of Psychiatry and Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut
| | - Kelly P Cosgrove
- Departments of Psychiatry and Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut
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Acute and sustained effects of methylphenidate on cognition and presynaptic dopamine metabolism: an [18F]FDOPA PET study. J Neurosci 2015; 34:14769-76. [PMID: 25355228 DOI: 10.1523/jneurosci.1560-14.2014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Methylphenidate (MPH) inhibits the reuptake of dopamine and noradrenaline. PET studies with MPH challenge show increased competition at postsynaptic D2/3-receptors, thus indirectly revealing presynaptic dopamine release. We used [(18)F]fluorodopamine ([(18)F]FDOPA)-PET in conjunction with the inlet-outlet model (IOM) of Kumakura et al. (2007) to investigate acute and long-term changes in dopamine synthesis capacity and turnover in nigrostriatal fibers of healthy subjects with MPH challenge. Twenty healthy human females underwent two dynamic [(18)F]FDOPA PET scans (124 min; slow bolus-injection; arterial blood sampling), with one scan in untreated baseline condition and the other after MPH administration (0.5 mg/kg, p.o.), in randomized order. Subjects underwent cognitive testing at each PET session. Time activity curves were obtained for ventral putamen and caudate and were analyzed according to the IOM to obtain the regional net-uptake of [(18)F]FDOPA (K; dopamine synthesis capacity) as well as the [(18)F]fluorodopamine washout rate (kloss, index of dopamine turnover). MPH substantially decreased kloss in putamen (-22%; p = 0.003). In the reversed treatment order group (MPH/no drug), K was increased by 18% at no drug follow-up. The magnitude of K at the no drug baseline correlated with cognitive parameters. Furthermore, individual kloss changes correlated with altered cognitive performance under MPH. [(18)F]FDOPA PET in combination with the IOM detects an MPH-evoked decrease in striatal dopamine turnover, in accordance with the known acute pharmacodynamics of MPH. Furthermore, the scan-ordering effect on K suggested that a single MPH challenge persistently increased striatal dopamine synthesis capacity. Attenuation of dopamine turnover by MPH is linked to enhanced cognitive performance in healthy females.
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11
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Deserno L, Beck A, Huys QJM, Lorenz RC, Buchert R, Buchholz HG, Plotkin M, Kumakara Y, Cumming P, Heinze HJ, Grace AA, Rapp MA, Schlagenhauf F, Heinz A. Chronic alcohol intake abolishes the relationship between dopamine synthesis capacity and learning signals in the ventral striatum. Eur J Neurosci 2014; 41:477-86. [PMID: 25546072 DOI: 10.1111/ejn.12802] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 11/12/2014] [Indexed: 11/28/2022]
Abstract
Drugs of abuse elicit dopamine release in the ventral striatum, possibly biasing dopamine-driven reinforcement learning towards drug-related reward at the expense of non-drug-related reward. Indeed, in alcohol-dependent patients, reactivity in dopaminergic target areas is shifted from non-drug-related stimuli towards drug-related stimuli. Such 'hijacked' dopamine signals may impair flexible learning from non-drug-related rewards, and thus promote craving for the drug of abuse. Here, we used functional magnetic resonance imaging to measure ventral striatal activation by reward prediction errors (RPEs) during a probabilistic reversal learning task in recently detoxified alcohol-dependent patients and healthy controls (N = 27). All participants also underwent 6-[(18) F]fluoro-DOPA positron emission tomography to assess ventral striatal dopamine synthesis capacity. Neither ventral striatal activation by RPEs nor striatal dopamine synthesis capacity differed between groups. However, ventral striatal coding of RPEs correlated inversely with craving in patients. Furthermore, we found a negative correlation between ventral striatal coding of RPEs and dopamine synthesis capacity in healthy controls, but not in alcohol-dependent patients. Moderator analyses showed that the magnitude of the association between dopamine synthesis capacity and RPE coding depended on the amount of chronic, habitual alcohol intake. Despite the relatively small sample size, a power analysis supports the reported results. Using a multimodal imaging approach, this study suggests that dopaminergic modulation of neural learning signals is disrupted in alcohol dependence in proportion to long-term alcohol intake of patients. Alcohol intake may perpetuate itself by interfering with dopaminergic modulation of neural learning signals in the ventral striatum, thus increasing craving for habitual drug intake.
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Affiliation(s)
- Lorenz Deserno
- Department of Psychiatry and Psychotherapy, Charité-Universitätsmedizin Berlin, Campus Mitte, Charitéplatz 1, 10117, Berlin, Germany; Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany
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