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Bach P, de Timary P, Gründer G, Cumming P. Molecular Imaging Studies of Alcohol Use Disorder. Curr Top Behav Neurosci 2023. [PMID: 36639552 DOI: 10.1007/7854_2022_414] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Alcohol use disorder (AUD) is a serious public health problem in many countries, bringing a gamut of health risks and impairments to individuals and a great burden to society. Despite the prevalence of a disease model of AUD, the current pharmacopeia does not present reliable treatments for AUD; approved treatments are confined to a narrow spectrum of medications engaging inhibitory γ-aminobutyric acid (GABA) neurotransmission and possibly excitatory N-methyl-D-aspartate (NMDA) receptors, and opioid receptor antagonists. Molecular imaging with positron emission tomography (PET) and single-photon emission computed tomography (SPECT) can open a window into the living brain and has provided diverse insights into the pathology of AUD. In this narrative review, we summarize the state of molecular imaging findings on the pharmacological action of ethanol and the neuropathological changes associated with AUD. Laboratory and preclinical imaging results highlight the interactions between ethanol and GABA A-type receptors (GABAAR), but the interpretation of such results is complicated by subtype specificity. An abundance of studies with the glucose metabolism tracer fluorodeoxyglucose (FDG) concur in showing cerebral hypometabolism after ethanol challenge, but there is relatively little data on long-term changes in AUD. Alcohol toxicity evokes neuroinflammation, which can be tracked using PET with ligands for the microglial marker translocator protein (TSPO). Several PET studies show reversible increases in TSPO binding in AUD individuals, and preclinical results suggest that opioid-antagonists can rescue from these inflammatory responses. There are numerous PET/SPECT studies showing changes in dopaminergic markers, generally consistent with an impairment in dopamine synthesis and release among AUD patients, as seen in a number of other addictions; this may reflect the composite of an underlying deficiency in reward mechanisms that predisposes to AUD, in conjunction with acquired alterations in dopamine signaling. There is little evidence for altered serotonin markers in AUD, but studies with opioid receptor ligands suggest a specific up-regulation of the μ-opioid receptor subtype. Considerable heterogeneity in drinking patterns, gender differences, and the variable contributions of genetics and pre-existing vulnerability traits present great challenges for charting the landscape of molecular imaging in AUD.
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Affiliation(s)
- Patrick Bach
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health, Heidelberg University, Mannheim, Germany.
| | - Philippe de Timary
- Department of Adult Psychiatry, Cliniques Universitaires Saint-Luc and Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Gerhard Gründer
- Department of Molecular Neuroimaging, Central Institute of Mental Health, Heidelberg University, Mannheim, Germany
| | - Paul Cumming
- Department of Nuclear Medicine, Bern University Hospital, Bern, Switzerland
- School of Psychology and Counselling, Queensland University of Technology, Brisbane, QLD, Australia
- International Centre for Education and Research in Neuropsychiatry (ICERN), Samara State Medical University, Samara, Russia
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Oldehinkel M, Llera A, Faber M, Huertas I, Buitelaar JK, Bloem BR, Marquand AF, Helmich R, Haak KV, Beckmann CF. Mapping dopaminergic projections in the human brain with resting-state fMRI. eLife 2022; 11:71846. [PMID: 35113016 PMCID: PMC8843090 DOI: 10.7554/elife.71846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 01/26/2022] [Indexed: 12/02/2022] Open
Abstract
The striatum receives dense dopaminergic projections, making it a key region of the dopaminergic system. Its dysfunction has been implicated in various conditions including Parkinson’s disease (PD) and substance use disorder. However, the investigation of dopamine-specific functioning in humans is problematic as current MRI approaches are unable to differentiate between dopaminergic and other projections. Here, we demonstrate that ‘connectopic mapping’ – a novel approach for characterizing fine-grained, overlapping modes of functional connectivity – can be used to map dopaminergic projections in striatum. We applied connectopic mapping to resting-state functional MRI data of the Human Connectome Project (population cohort; N = 839) and selected the second-order striatal connectivity mode for further analyses. We first validated its specificity to dopaminergic projections by demonstrating a high spatial correlation (r = 0.884) with dopamine transporter availability – a marker of dopaminergic projections – derived from DaT SPECT scans of 209 healthy controls. Next, we obtained the subject-specific second-order modes from 20 controls and 39 PD patients scanned under placebo and under dopamine replacement therapy (L-DOPA), and show that our proposed dopaminergic marker tracks PD diagnosis, symptom severity, and sensitivity to L-DOPA. Finally, across 30 daily alcohol users and 38 daily smokers, we establish strong associations with self-reported alcohol and nicotine use. Our findings provide evidence that the second-order mode of functional connectivity in striatum maps onto dopaminergic projections, tracks inter-individual differences in PD symptom severity and L-DOPA sensitivity, and exhibits strong associations with levels of nicotine and alcohol use, thereby offering a new biomarker for dopamine-related (dys)function in the human brain.
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Affiliation(s)
- Marianne Oldehinkel
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Alberto Llera
- Donders Institute for Brain, Cognition and Behaviour, Radboud, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Myrthe Faber
- Donders Institute for Brain, Cognition and Behaviour, Radboud, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Ismael Huertas
- Institute of Biomedicine of Seville (IBiS), Seville, Spain
| | - Jan K Buitelaar
- Donders Institute for Brain, Cognition and Behaviour, Radboud, Radboud University Medical Center, Nijmegen, Netherlands
| | - Bastiaan R Bloem
- Department of Neurology, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Andre F Marquand
- Donders Institute for Brain, Cognition and Behaviour, Radboud, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Rick Helmich
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Koen V Haak
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Christian F Beckmann
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, Netherlands
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Xu S, Jeong SJ, Li G, Koo JW, Kang UG. Repeated ethanol exposure influences key enzymes in cholesterol and lipid homeostasis via the AMPK pathway in the rat prefrontal cortex. Alcohol 2020; 85:49-56. [PMID: 31734306 DOI: 10.1016/j.alcohol.2019.11.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/24/2019] [Accepted: 11/07/2019] [Indexed: 11/25/2022]
Abstract
Cholesterol homeostasis has been proposed to be implicated in the development of addiction. However, the effects of ethanol on cholesterol homeostasis within the brain are not well understood. One of the most important regulators of cholesterol homeostasis is HMG-CoA reductase (HMG-CoAR), the rate-limiting enzyme of cholesterol biosynthesis. We examined the phosphorylation of HMG-CoAR and the other key regulator of lipid synthesis, acetyl-CoA carboxylase (ACC), following acute or chronic treatment with ethanol (0.5, 1, or 2 g/kg) in the rat prefrontal cortex. The phosphorylation of AMP-activated protein kinase (AMPK), which regulates the HMG-CoAR activity, and its well-known upstream regulators, was also studied. The phosphorylation of HMG-CoAR and ACC were transiently increased by ethanol treatment only in animals previously treated chronically with ethanol. Acute administration to naïve animals did not induce the phosphorylation, regardless of dosage. Similarly, the phosphorylation of AMPK and the upstream regulators, LKB1 and CaMK4, were transiently increased only in chronically ethanol-treated animals. In naïve animals, a high dose (2 g/kg) of ethanol decreased phosphorylation. The phosphorylation of TAK1, another upstream kinase of AMPK, was increased only from 30 min to 24 h after the chronic treatment with ethanol. Together, these results indicate that repeated exposure is required for the activating effect of ethanol on HMG-CoAR and ACC. This effect seems to be mediated by the AMPK system, and may contribute to the long-lasting neuroadaptation involved in the development of alcohol dependence.
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Hansson AC, Gründer G, Hirth N, Noori HR, Spanagel R, Sommer WH. Dopamine and opioid systems adaptation in alcoholism revisited: Convergent evidence from positron emission tomography and postmortem studies. Neurosci Biobehav Rev 2019; 106:141-164. [DOI: 10.1016/j.neubiorev.2018.09.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 09/08/2018] [Accepted: 09/14/2018] [Indexed: 12/20/2022]
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Nikolaus S, Mamlins E, Hautzel H, Müller HW. Acute anxiety disorder, major depressive disorder, bipolar disorder and schizophrenia are related to different patterns of nigrostriatal and mesolimbic dopamine dysfunction. Rev Neurosci 2019; 30:381-426. [PMID: 30269107 DOI: 10.1515/revneuro-2018-0037] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 06/30/2018] [Indexed: 11/15/2022]
Abstract
Dopamine (DA) receptor and transporter dysfunctions play a major role in the pathophysiology of neuropsychiatric diseases including anxiety disorder (AD), major depressive disorder (MDD), bipolar disorder (BD) in the manic (BDman) or depressive (BDdep) state and schizophrenia (SZ). We performed a PUBMED search, which provided a total of 239 in vivo imaging studies with either positron emission tomography (PET) or single-proton emission computed tomography (SPECT). In these studies, DA transporter binding, D1 receptor (R) binding, D2R binding, DA synthesis and/or DA release in patients with the primary diagnosis of acute AD (n=310), MDD (n=754), BDman (n=15), BDdep (n=49) or SZ (n=1532) were compared to healthy individuals. A retrospective analysis revealed that AD, MDD, BDman, BDdep and SZ differed as to affected brain region(s), affected synaptic constituent(s) and extent as well as direction of dysfunction in terms of either sensitization or desensitization of transporter and/or receptor binding sites. In contrast to AD and SZ, in MDD, BDman and BDdep, neostriatal DA function was normal, whereas MDD, BDman, and BDdep were characterized by the increased availability of prefrontal and frontal DA. In contrast to AD, MDD, BDman and BDdep, DA function in SZ was impaired throughout the nigrostriatal and mesolimbocortical system with an increased availability of DA in the striatothalamocortical and a decreased availability in the mesolimbocortical pathway.
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Affiliation(s)
- Susanne Nikolaus
- Clinic of Nuclear Medicine, University Hospital Düsseldorf, Heinrich Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Eduards Mamlins
- Clinic of Nuclear Medicine, University Hospital Düsseldorf, Heinrich Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Hubertus Hautzel
- Clinic of Nuclear Medicine, University Hospital Düsseldorf, Heinrich Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Hans-Wilhelm Müller
- Clinic of Nuclear Medicine, University Hospital Düsseldorf, Heinrich Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
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Coppens V, Morrens M, Destoop M, Dom G. The Interplay of Inflammatory Processes and Cognition in Alcohol Use Disorders-A Systematic Review. Front Psychiatry 2019; 10:632. [PMID: 31572234 PMCID: PMC6751886 DOI: 10.3389/fpsyt.2019.00632] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 08/06/2019] [Indexed: 12/12/2022] Open
Abstract
Rationale: Of late, evidence emerges that the pathophysiology of psychiatric diseases and their affiliated symptomatologies are at least partly contributable to inflammatory processes. Also in alcohol use disorders (AUD), this interaction is strongly apparent, with severely immunogenic liver cirrhosis being one of the most critical sequelae of chronic abusive drinking. This somatic immune system activation negatively impacts brain functioning, and additionally, alcohol abuse appears to have a direct detrimental effect on the brain by actively stimulating its immune cells and responses. As cognitive decline majorly contributes to AUD's debility, it is important to know to what extent impairment of cognitive functioning is due to these (neuro-)inflammatory aberrations. Method: We hereby summarize the current existing literature on the interplay between AUD, inflammation, and cognition in a systematic review according to the PRISMA-P guidelines for the systematic review. Main findings: Although literature on the role of inflammation in alcohol use-related cognitive deficiency remains scarce, current findings indicate that pro-inflammatory processes indeed result in exacerbation of several domains of cognitive deterioration. Interestingly, microglia, the immune cells of the brain, appear to exert initial compensatory neuroprotective functionalities upon acute ethanol exposure while chronic alcohol intake seems to attenuate these responses and overall microglial activity. Conclusion: As these results indicate inflammation to be of importance in cognitive impairment following alcohol consumption and might as such provide alternate therapeutic avenues, a considerable increase in research efforts in this domain is urgently required.
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Affiliation(s)
- Violette Coppens
- Faculty of Medicine and Health Sciences, Collaborative Antwerp Psychiatric Research Institute (CAPRI), University of Antwerp, Antwerp, Belgium.,Scientific Initiative of Neuropsychiatric and Psychopharmacological Studies (SINAPS), University Department of Psychiatry, Duffel, Belgium
| | - Manuel Morrens
- Faculty of Medicine and Health Sciences, Collaborative Antwerp Psychiatric Research Institute (CAPRI), University of Antwerp, Antwerp, Belgium.,Scientific Initiative of Neuropsychiatric and Psychopharmacological Studies (SINAPS), University Department of Psychiatry, Duffel, Belgium
| | - Marianne Destoop
- Faculty of Medicine and Health Sciences, Collaborative Antwerp Psychiatric Research Institute (CAPRI), University of Antwerp, Antwerp, Belgium.,Department of Addiction, Psychiatric Hospital Multiversum, Boechout, Belgium
| | - Geert Dom
- Faculty of Medicine and Health Sciences, Collaborative Antwerp Psychiatric Research Institute (CAPRI), University of Antwerp, Antwerp, Belgium.,Department of Addiction, Psychiatric Hospital Multiversum, Boechout, Belgium
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Siciliano CA, Karkhanis AN, Holleran KM, Melchior JR, Jones SR. Cross-Species Alterations in Synaptic Dopamine Regulation After Chronic Alcohol Exposure. Handb Exp Pharmacol 2018; 248:213-238. [PMID: 29675581 PMCID: PMC6195853 DOI: 10.1007/164_2018_106] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Alcohol use disorders are a leading public health concern, engendering enormous costs in terms of both economic loss and human suffering. These disorders are characterized by compulsive and excessive alcohol use, as well as negative affect and alcohol craving during abstinence. Extensive research has implicated the dopamine system in both the acute pharmacological effects of alcohol and the symptomology of alcohol use disorders that develop after extended alcohol use. Preclinical research has shed light on many mechanisms by which chronic alcohol exposure dysregulates the dopamine system. However, many of the findings are inconsistent across experimental parameters such as alcohol exposure length, route of administration, and model organism. We propose that the dopaminergic alterations driving the core symptomology of alcohol use disorders are likely to be relatively stable across experimental settings. Recent work has been aimed at using multiple model organisms (mouse, rat, monkey) across various alcohol exposure procedures to search for commonalities. Here, we review recent advances in our understanding of the effects of chronic alcohol use on the dopamine system by highlighting findings that are consistent across experimental setting and species.
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Affiliation(s)
- Cody A Siciliano
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Anushree N Karkhanis
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Katherine M Holleran
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - James R Melchior
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Sara R Jones
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA.
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