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Millevert C, Vidas-Guscic N, Vanherp L, Jonckers E, Verhoye M, Staelens S, Bertoglio D, Weckhuysen S. Resting-State Functional MRI and PET Imaging as Noninvasive Tools to Study (Ab)Normal Neurodevelopment in Humans and Rodents. J Neurosci 2023; 43:8275-8293. [PMID: 38073598 PMCID: PMC10711730 DOI: 10.1523/jneurosci.1043-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 06/09/2023] [Accepted: 09/13/2023] [Indexed: 12/18/2023] Open
Abstract
Neurodevelopmental disorders (NDDs) are a group of complex neurologic and psychiatric disorders. Functional and molecular imaging techniques, such as resting-state functional magnetic resonance imaging (rs-fMRI) and positron emission tomography (PET), can be used to measure network activity noninvasively and longitudinally during maturation in both humans and rodent models. Here, we review the current knowledge on rs-fMRI and PET biomarkers in the study of normal and abnormal neurodevelopment, including intellectual disability (ID; with/without epilepsy), autism spectrum disorder (ASD), and attention deficit hyperactivity disorder (ADHD), in humans and rodent models from birth until adulthood, and evaluate the cross-species translational value of the imaging biomarkers. To date, only a few isolated studies have used rs-fMRI or PET to study (abnormal) neurodevelopment in rodents during infancy, the critical period of neurodevelopment. Further work to explore the feasibility of performing functional imaging studies in infant rodent models is essential, as rs-fMRI and PET imaging in transgenic rodent models of NDDs are powerful techniques for studying disease pathogenesis, developing noninvasive preclinical imaging biomarkers of neurodevelopmental dysfunction, and evaluating treatment-response in disease-specific models.
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Affiliation(s)
- Charissa Millevert
- Applied & Translational Neurogenomics Group, Vlaams Instituut voor Biotechnology (VIB) Center for Molecular Neurology, VIB, Antwerp 2610, Belgium
- Department of Neurology, University Hospital of Antwerp, Antwerp 2610, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp 2610, Belgium
| | - Nicholas Vidas-Guscic
- Bio-Imaging Lab, University of Antwerp, Antwerp 2610, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp 2610, Belgium
| | - Liesbeth Vanherp
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp 2610, Belgium
| | - Elisabeth Jonckers
- Bio-Imaging Lab, University of Antwerp, Antwerp 2610, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp 2610, Belgium
| | - Marleen Verhoye
- Bio-Imaging Lab, University of Antwerp, Antwerp 2610, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp 2610, Belgium
| | - Steven Staelens
- Molecular Imaging Center Antwerp (MICA), University of Antwerp, Antwerp 2610, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp 2610, Belgium
| | - Daniele Bertoglio
- Bio-Imaging Lab, University of Antwerp, Antwerp 2610, Belgium
- Molecular Imaging Center Antwerp (MICA), University of Antwerp, Antwerp 2610, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp 2610, Belgium
| | - Sarah Weckhuysen
- Applied & Translational Neurogenomics Group, Vlaams Instituut voor Biotechnology (VIB) Center for Molecular Neurology, VIB, Antwerp 2610, Belgium
- Department of Neurology, University Hospital of Antwerp, Antwerp 2610, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp 2610, Belgium
- Translational Neurosciences, Faculty of Medicine and Health Science, University of Antwerp, Antwerp 2610, Belgium
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Hámor PU, Knackstedt LA, Schwendt M. The role of metabotropic glutamate receptors in neurobehavioral effects associated with methamphetamine use. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2023; 168:177-219. [PMID: 36868629 DOI: 10.1016/bs.irn.2022.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Metabotropic glutamate (mGlu) receptors are expressed throughout the central nervous system and act as important regulators of drug-induced neuroplasticity and behavior. Preclinical research suggests that mGlu receptors play a critical role in a spectrum of neural and behavioral consequences arising from methamphetamine (meth) exposure. However, an overview of mGlu-dependent mechanisms linked to neurochemical, synaptic, and behavioral changes produced by meth has been lacking. This chapter provides a comprehensive review of the role of mGlu receptor subtypes (mGlu1-8) in meth-induced neural effects, such as neurotoxicity, as well as meth-associated behaviors, such as psychomotor activation, reward, reinforcement, and meth-seeking. Additionally, evidence linking altered mGlu receptor function to post-meth learning and cognitive deficits is critically evaluated. The chapter also considers the role of receptor-receptor interactions involving mGlu receptors and other neurotransmitter receptors in meth-induced neural and behavioral changes. Taken together, the literature indicates that mGlu5 regulates the neurotoxic effects of meth by attenuating hyperthermia and possibly through altering meth-induced phosphorylation of the dopamine transporter. A cohesive body of work also shows that mGlu5 antagonism (and mGlu2/3 agonism) reduce meth-seeking, though some mGlu5-blocking drugs also attenuate food-seeking. Further, evidence suggests that mGlu5 plays an important role in extinction of meth-seeking behavior. In the context of a history of meth intake, mGlu5 also co-regulates aspects of episodic memory, with mGlu5 stimulation restoring impaired memory. Based on these findings, we propose several avenues for the development of novel pharmacotherapies for Methamphetamine Use Disorder based on the selective modulation mGlu receptor subtype activity.
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Affiliation(s)
- Peter U Hámor
- Department of Psychology, University of Florida, Gainesville, FL, United States; Center for Addiction Research and Education, University of Florida, Gainesville, FL, United States; Department of Pharmacology, Weill Cornell Medicine, Cornell University, New York, NY, United States
| | - Lori A Knackstedt
- Department of Psychology, University of Florida, Gainesville, FL, United States; Center for Addiction Research and Education, University of Florida, Gainesville, FL, United States
| | - Marek Schwendt
- Department of Psychology, University of Florida, Gainesville, FL, United States; Center for Addiction Research and Education, University of Florida, Gainesville, FL, United States.
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Asch RH, Hillmer AT, Baldassarri SR, Esterlis I. The metabotropic glutamate receptor 5 as a biomarker for psychiatric disorders. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2023; 168:265-310. [PMID: 36868631 DOI: 10.1016/bs.irn.2022.10.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The role of glutamate system in the etiology and pathophysiology of psychiatric disorders has gained considerable attention in the past two decades, including dysregulation of the metabotropic glutamatergic receptor subtype 5 (mGlu5). Thus, mGlu5 may represent a promising therapeutic target for psychiatric conditions, particularly stress-related disorders. Here, we describe mGlu5 findings in mood disorders, anxiety, and trauma disorders, as well as substance use (specifically nicotine, cannabis, and alcohol use). We highlight insights gained from positron emission tomography (PET) studies, where possible, and discuss findings from treatment trials, when available, to explore the role of mGlu5 in these psychiatric disorders. Through the research evidence reviewed in this chapter, we make the argument that, not only is dysregulation of mGlu5 evident in numerous psychiatric disorders, potentially functioning as a disease "biomarker," the normalization of glutamate neurotransmission via changes in mGlu5 expression and/or modulation of mGlu5 signaling may be a needed component in treating some psychiatric disorders or symptoms. Finally, we hope to demonstrate the utility of PET as an important tool for investigating mGlu5 in disease mechanisms and treatment response.
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Affiliation(s)
- Ruth H Asch
- Department of Psychiatry, Yale University, New Haven, CT, United States.
| | - Ansel T Hillmer
- Department of Psychiatry, Yale University, New Haven, CT, United States; Department of Radiology and Biomedical Imaging, New Haven, CT, United States
| | - Stephen R Baldassarri
- Yale Program in Addiction Medicine, Yale University, New Haven, CT, United States; Department of Internal Medicine, Yale University, New Haven, CT, United States
| | - Irina Esterlis
- Department of Psychiatry, Yale University, New Haven, CT, United States; Department of Psychology, Yale University, New Haven, CT, United States; Clinical Neurosciences Division, U.S. Department of Veterans Affairs National Center for Posttraumatic Stress Disorder, Veterans Affairs Connecticut Healthcare System, West Haven, CT, United States
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4
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Mecca AP, Rogers K, Jacobs Z, McDonald JW, Michalak HR, DellaGioia N, Zhao W, Hillmer AT, Nabulsi N, Lim K, Ropchan J, Huang Y, Matuskey D, Esterlis I, Carson RE, van Dyck CH. Effect of age on brain metabotropic glutamate receptor subtype 5 measured with [ 18F]FPEB PET. Neuroimage 2021; 238:118217. [PMID: 34052464 PMCID: PMC8378132 DOI: 10.1016/j.neuroimage.2021.118217] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 04/08/2021] [Accepted: 05/26/2021] [Indexed: 12/31/2022] Open
Abstract
OBJECTIVE Metabotropic glutamate receptor subtype 5 (mGluR5) is integral to the brain glutamatergic system and cognitive function. This study investigated whether aging is associated with decreased brain mGluR5 availability. METHODS Cognitively normal participants (n = 45), aged 18 to 84 years, underwent [18F]FPEB positron emission tomography scans to quantify brain mGluR5. Distribution volume (VT) was computed using a venous or arterial input function and equilibrium modeling from 90 to 120 min. In the primary analysis, the association between age and VT in the hippocampus and association cortex was evaluated using a linear mixed model. Exploratory analyses assessed the association between age and VT in multiple brain regions. The contribution of gray matter tissue alterations and partial volume effects to associations with age was also examined. RESULTS In the primary analysis, older age was associated with lower [18F]FPEB binding to mGluR5 (P = 0.026), whereas this association was not significant after gray matter masking or partial volume correction to account for age-related tissue loss. Post hoc analyses revealed an age-related decline in mGluR5 availability in the hippocampus of 4.5% per decade (P = 0.007) and a non-significant trend in the association cortex (P = 0.085). An exploratory analysis of multiple brain regions revealed broader inverse associations of age with mGluR5 availability, but not after partial volume correction. CONCLUSION Reductions in mGluR5 availability with age appear to be largely mediated by tissue loss. Quantification of [18F]FPEB binding to mGluR5 may expand our understanding of age-related molecular changes and the relationship with brain tissue loss.
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Affiliation(s)
- Adam P Mecca
- Alzheimer's Disease Research Unit, Yale University School of Medicine, One Church Street, 8th Floor, New Haven, CT, 06514, USA; Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA.
| | - Kelly Rogers
- Alzheimer's Disease Research Unit, Yale University School of Medicine, One Church Street, 8th Floor, New Haven, CT, 06514, USA; Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Zachary Jacobs
- Alzheimer's Disease Research Unit, Yale University School of Medicine, One Church Street, 8th Floor, New Haven, CT, 06514, USA; Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Julia W McDonald
- Alzheimer's Disease Research Unit, Yale University School of Medicine, One Church Street, 8th Floor, New Haven, CT, 06514, USA; Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Hannah R Michalak
- Alzheimer's Disease Research Unit, Yale University School of Medicine, One Church Street, 8th Floor, New Haven, CT, 06514, USA; Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Nicole DellaGioia
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Wenzhen Zhao
- Alzheimer's Disease Research Unit, Yale University School of Medicine, One Church Street, 8th Floor, New Haven, CT, 06514, USA; Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Ansel T Hillmer
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA; Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Nabeel Nabulsi
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Keunpoong Lim
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Jim Ropchan
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Yiyun Huang
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - David Matuskey
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA; Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA; Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
| | - Irina Esterlis
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Richard E Carson
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Christopher H van Dyck
- Alzheimer's Disease Research Unit, Yale University School of Medicine, One Church Street, 8th Floor, New Haven, CT, 06514, USA; Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA; Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA; Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
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Zoccatelli G, Alessandrini F, Rimondo C, Beltramello A, Serpelloni G, M Ciceri EF. Magnetic Resonance Spectroscopy in Adolescent Cannabis Users: Metabolites in the Anterior Cingulate Cortex Reflects Individual Differences in Personality Traits and can Affect Rehabilitation Compliance. Neurol India 2021; 68:640-647. [PMID: 32643678 DOI: 10.4103/0028-3886.288984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Introduction The anterior cingulate cortex (ACC) has shown to play a role in impulsivity, fear, and anxiety. Considering, its high glutamate receptor density, it was chosen as a region of interest to investigate the role of glutamate transmission in drug dependance. We investigated the correlations between personality trait scores and glutamate-to-glutamine (Glx) ratio concentrations in the ACC in order to evaluate if (1) personality traits may increase the probability of drug use and (2) drug use can modify cerebral metabolic pattern contributing to addictive behaviors. Materials and Methods Glx ratio concentrations in the ACC region were measured with high-resolution multivoxel proton magnetic resonance spectroscopy (1H-MRS). Personality traits were evaluated utilizing Cloninger's TCI-revised test. Bivariate correlations between personality scores of 28 teens cannabis users (males, mean age = 18.54 ± 2.80) were evaluated. Results In the ACC, we observed negative correlation between GG concentrations (r = -0.44, P = 0.05) and co-operativeness values (CO), choline (cho), and novelty seeking (NS) values (r = -0,45, P = 0.05). Low levels of glutamate and high levels of cho in the ACC were closely related to the CO and NS personality traits. Conclusions Metabolic and personality patterns seems to be related to the risk of substance predisposition in adolescents. Our data contribute a possible support to the "top-down" control of the ACC on brain metabolism, due to the particular cerebral metabolic pattern found in "drug-using" adolescents.
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Affiliation(s)
- Giada Zoccatelli
- Department of Diagnostics and Pathology, University Hospital of Verona, Verona, Italy
| | - Franco Alessandrini
- Department of Diagnostics and Pathology, University Hospital of Verona, Verona, Italy
| | - Claudia Rimondo
- Italian Early Warning System on Drugs, Presidency of the Council of Ministers, Rome, Italy
| | | | - Giovanni Serpelloni
- Department of Psychiatry, College of Medicine, University of Florida- Drug Policy Institute, Gainesville, FL, United States
| | - Elisa F M Ciceri
- Department of Diagnostics and Pathology, University Hospital of Verona, Verona; IRCCS Fondazione Istituto Neurologico "C.Besta", Milan, Italy
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Müller Herde A, Mihov Y, Krämer SD, Mu L, Adamantidis A, Ametamey SM, Hasler G. Chronic Nicotine Exposure Alters Metabotropic Glutamate Receptor 5: Longitudinal PET Study and Behavioural Assessment in Rats. Neurotox Res 2019; 36:806-816. [PMID: 31119680 DOI: 10.1007/s12640-019-00055-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 03/22/2019] [Accepted: 04/26/2019] [Indexed: 12/13/2022]
Abstract
Using positron emission tomography (PET), a profound alteration of the metabotropic glutamate receptor 5 (mGluR5) was found in human smoking addiction and abstinence. As human PET data either reflect the impact of chronic nicotine exposure or a pre-existing vulnerability to nicotine addiction, we designed a preclinical, longitudinal study to investigate the effect of chronic nicotine exposure on mGluR5 with the novel radiotracer [18F]PSS232 using PET. Twelve male dark Agouti rats at the age of 6 weeks were assigned randomly to three groups. From day 0 to day 250 the groups received 0 mg/L, 4 mg/L, or 8 mg/L nicotine solution in the drinking water. From day 250 to 320 all groups received nicotine-free drinking water. PET scans with [18F]PSS232 were performed in all animals on days 0, 250, and 320. To assess locomotion, seven tests in square open field arenas were carried out 72 days after the last PET scan. During the first four tests, rats received 0 mg/L nicotine and for the last three tests 4 mg/L nicotine in the drinking water. After 250 days of nicotine consumption [18F]PSS232 binding was reduced in the striatum, hippocampus, thalamus, and midbrain. At day 320, after nicotine withdrawal, [18F]PSS232 binding increased. These effects were more pronounced in the 4 mg/L nicotine group. Chronic administration of nicotine through the drinking water reduced exploratory behaviour. This preliminary longitudinal PET study demonstrates that chronic nicotine administration alters behaviour and mGluR5 availability. Chronic nicotine administration leads to decreased [18F]PSS232 binding which normalizes after prolonged nicotine withdrawal.
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Affiliation(s)
- Adrienne Müller Herde
- Center for Radiopharmaceutical Sciences of ETH, PSI, and USZ, Department of Chemistry and Applied Biosciences of ETH, 8093, Zurich, Switzerland
| | - Yoan Mihov
- Translational Research Center, University Hospital of Psychiatry, University of Bern, 3000, Bern 60, Switzerland
| | - Stefanie D Krämer
- Center for Radiopharmaceutical Sciences of ETH, PSI, and USZ, Department of Chemistry and Applied Biosciences of ETH, 8093, Zurich, Switzerland
| | - Linjing Mu
- Department of Nuclear Medicine, University Hospital Zurich, Center for Radiopharmaceutical Sciences of ETH, PSI, and USZ, 8091, Zurich, Switzerland
| | - Antoine Adamantidis
- Department of Biomedical Research, Inselspital University Hospital, University of Bern, 3000, Bern, Switzerland
- Centre for Experimental Neurology, Department of Neurology, Inselspital University Hospital, University of Bern, Bern, Switzerland
| | - Simon M Ametamey
- Center for Radiopharmaceutical Sciences of ETH, PSI, and USZ, Department of Chemistry and Applied Biosciences of ETH, 8093, Zurich, Switzerland
| | - Gregor Hasler
- Psychiatry Research Unit, University of Fribourg, Chemin du Cardinal-Journet 3, Villars-sur-Glâne, 1752, Fribourg, Switzerland.
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Ceccarini J, Leurquin-Sterk G, Crunelle CL, de Laat B, Bormans G, Peuskens H, Van Laere K. Recovery of Decreased Metabotropic Glutamate Receptor 5 Availability in Abstinent Alcohol-Dependent Patients. J Nucl Med 2019; 61:256-262. [PMID: 31481578 DOI: 10.2967/jnumed.119.228825] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 07/19/2019] [Indexed: 12/21/2022] Open
Abstract
Animal models of alcohol dependence and relapse demonstrate an important role of the glutamatergic system, in particular, cerebral metabotropic glutamate receptor 5 (mGluR5). 18F-3-fluoro-5-[(pyridin-3-yl)ethynyl]benzonitrile (18F-FPEB) PET has revealed that chronic alcohol use leads to decreased limbic mGluR5 availability, which was associated with less craving. Here, we tested whether the state of decreased mGluR5 availability in alcohol-dependent patients normalizes during abstinence (at 2 and 6 mo of detoxification) and whether initial mGluR5 imaging parameters can predict individual relapse. Methods: 18F-FPEB scans were performed for 16 recently detoxified alcohol-dependent patients (baseline condition), 2 mo after detoxification (n = 10), and 6 mo after detoxification (n = 8); 32 age- and sex-matched controls were included for comparison. mGluR5 availability was quantified by the 18F-FPEB total distribution volume using both voxel-by-voxel and volume-of-interest analyses. During follow-up, craving was assessed using the Desire for Alcohol Questionnaire, and alcohol consumption was assessed using the timeline follow-back method and monitored by hair ethyl glucuronide analysis. Results: During abstinence, alcohol-dependent patients showed sustained recovered mGluR5 availability in cortical and subcortical regions compared with the baseline, up to the levels observed in controls, after 6 mo in most areas except for the hippocampus, nucleus accumbens, and thalamus. Higher striatopallidal mGluR5 availability was observed at the baseline in patients who had a relapse during the 6-mo follow-up period (+25.1%). Also, normalization of striatal mGluR5 to control levels was associated with reduced craving ("desire and intention to drink" and "negative reinforcement"; r = 0.72-0.94). Conclusion: Reduced cerebral mGluR5 availability in alcohol-dependent patients recovers during abstinence and is associated with reduced craving. Higher striatal mGluR5 availability in alcohol-dependent users may be associated with long-term relapse.
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Affiliation(s)
- Jenny Ceccarini
- Department of Nuclear Medicine and Molecular Imaging, UZ Leuven, Leuven, Belgium .,Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Gil Leurquin-Sterk
- Department of Nuclear Medicine and Molecular Imaging, UZ Leuven, Leuven, Belgium.,Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Cleo Lina Crunelle
- Toxicological Center, University of Antwerp, Wilrijk, Belgium.,Department of Psychiatry, Universitair Ziekenhuis Brussel, Brussels, Belgium
| | - Bart de Laat
- Department of Nuclear Medicine and Molecular Imaging, UZ Leuven, Leuven, Belgium.,Department of Imaging and Pathology, KU Leuven, Leuven, Belgium.,MoSAIC, Molecular Small Animal Imaging Center, KU Leuven, Leuven, Belgium
| | - Guy Bormans
- Laboratory for Radiopharmacy, KU Leuven, Leuven, Belgium
| | - Hendrik Peuskens
- University Psychiatric Center, KU Leuven, Kortenberg, Belgium; and.,Kliniek Broeders Alexianen, Tienen, Belgium
| | - Koen Van Laere
- Department of Nuclear Medicine and Molecular Imaging, UZ Leuven, Leuven, Belgium.,Department of Imaging and Pathology, KU Leuven, Leuven, Belgium.,MoSAIC, Molecular Small Animal Imaging Center, KU Leuven, Leuven, Belgium
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Laukkanen V, Kärkkäinen O, Kautiainen H, Tiihonen J, Storvik M. Increased [³H]quisqualic acid binding density in the dorsal striatum and anterior insula of alcoholics: A post-mortem whole-hemisphere autoradiography study. Psychiatry Res Neuroimaging 2019; 287:63-69. [PMID: 30991250 DOI: 10.1016/j.pscychresns.2019.04.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 04/05/2019] [Accepted: 04/07/2019] [Indexed: 01/28/2023]
Abstract
The function of group I metabotropic glutamate receptors mGluR1 and mGluR5 is involved in the hyperglutamatergic state caused by chronic alcohol. Preclinical studies suggest that group I mGluR modulation could serve as a novel treatment of alcoholism. Considering the wide role of glutamatergic neurochemistry in addiction, group I mGluR binding was studied in brain areas involved in decision-making, learning and memory. Post-mortem whole hemisphere autoradiography was used to study the binding density of [³H]quisqualic acid, a potent group I mGluR agonist, in 9 Cloninger type 1 alcoholics, 8 Cloninger type 2 alcoholics and 10 controls. Binding was studied in the dorsal striatum, hippocampus and cortex. Alcoholics displayed a trend towards increased [³H]quisqualic acid binding in all brain areas. The most robust findings were in the putamen (p = 0.006) and anterior insula (p = 0.005), where both alcoholic subtypes displayed increased binding compared to the controls. These findings suggest altered group I mGluR function in alcoholic subjects in the dorsal striatum, which is involved in habitual learning, and in the anterior insula, which has a pivotal role in the perception of bodily sensations. Increased [³H]quisqualic acid binding might suggest a beneficial impact of mGluR1/5 modulators in the treatment of alcoholism.
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Affiliation(s)
- Virpi Laukkanen
- Department of Forensic Psychiatry, University of Eastern Finland, Niuvanniemi Hospital, Niuvankuja 65, FI-70240 Kuopio, Finland; Department of Psychiatry, Kuopio University Hospital, P.O. Box 100, FI-70029 Kuopio, Finland.
| | - Olli Kärkkäinen
- Department of Pharmacology and Toxicology, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland
| | - Hannu Kautiainen
- Unit of Primary Health Care, Helsinki University Central Hospital, P.O. Box 705, FI-00029 HUS, Helsinki, Finland; Department of General Practice, Helsinki University, P.O. Box 20, FI-00014 Helsinki, Finland
| | - Jari Tiihonen
- Department of Forensic Psychiatry, University of Eastern Finland, Niuvanniemi Hospital, Niuvankuja 65, FI-70240 Kuopio, Finland; Department of Clinical Neuroscience, Karolinska Institutet, Karolinska Hospital, 17176 Stockholm, Sweden
| | - Markus Storvik
- Department of Psychiatry, Kuopio University Hospital, P.O. Box 100, FI-70029 Kuopio, Finland
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Dickson PE, Roy TA, McNaughton KA, Wilcox TD, Kumar P, Chesler EJ. Systems genetics of sensation seeking. GENES BRAIN AND BEHAVIOR 2018; 18:e12519. [PMID: 30221471 PMCID: PMC6399063 DOI: 10.1111/gbb.12519] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 09/09/2018] [Accepted: 09/11/2018] [Indexed: 02/06/2023]
Abstract
Sensation seeking is a multifaceted, heritable trait which predicts the development of substance use and abuse in humans; similar phenomena have been observed in rodents. Genetic correlations among sensation seeking and substance use indicate shared biological mechanisms, but the genes and networks underlying these relationships remain elusive. Here, we used a systems genetics approach in the BXD recombinant inbred mouse panel to identify shared genetic mechanisms underlying substance use and preference for sensory stimuli, an intermediate phenotype of sensation seeking. Using the operant sensation seeking (OSS) paradigm, we quantified preference for sensory stimuli in 120 male and 127 female mice from 62 BXD strains and the C57BL/6J and DBA/2J founder strains. We used relative preference for the active and inactive levers to dissociate preference for sensory stimuli from locomotion and exploration phenotypes. We identified genomic regions on chromosome 4 (155.236‐155.742 Mb) and chromosome 13 (72.969‐89.423 Mb) associated with distinct behavioral components of OSS. Using publicly available behavioral data and mRNA expression data from brain regions involved in reward processing, we identified (a) genes within these behavioral QTL exhibiting genome‐wide significant cis‐eQTL and (b) genetic correlations among OSS phenotypes, ethanol phenotypes and mRNA expression. From these analyses, we nominated positional candidates for behavioral QTL associated with distinct OSS phenotypes including Gnb1 and Mef2c. Genetic covariation of Gnb1 expression, preference for sensory stimuli and multiple ethanol phenotypes suggest that heritable variation in Gnb1 expression in reward circuitry partially underlies the widely reported relationship between sensation seeking and substance use.
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Affiliation(s)
- Price E. Dickson
- Center for Systems Neurogenetics of AddictionThe Jackson LaboratoryBar HarborMaine
| | - Tyler A. Roy
- Center for Systems Neurogenetics of AddictionThe Jackson LaboratoryBar HarborMaine
| | | | - Troy D. Wilcox
- Center for Systems Neurogenetics of AddictionThe Jackson LaboratoryBar HarborMaine
| | - Padam Kumar
- Center for Systems Neurogenetics of AddictionThe Jackson LaboratoryBar HarborMaine
| | - Elissa J. Chesler
- Center for Systems Neurogenetics of AddictionThe Jackson LaboratoryBar HarborMaine
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Havlík M, Mladá K, Fajnerová I, Horáček J. Do Personality Features Influence Our Intuitions of the Mind-Body Problem? A Pilot Study. Front Psychol 2018; 9:1219. [PMID: 30079041 PMCID: PMC6062648 DOI: 10.3389/fpsyg.2018.01219] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 06/27/2018] [Indexed: 11/13/2022] Open
Abstract
The elusive relationship between the mental domain and the physical brain, known as the mind-body problem, is still a hot topic of discussion among philosophers and neuroscientists. Rather than solving this problem, our pilot study addresses the question as to whether personality features could influence intuitions of the mind-body problem, or more precisely, whether it is possible to identify a person’s intuitive inclinations toward dualism or materialism and their inclinations toward reduction of the mind to the brain. For the purposes of this pilot study, we developed a questionnaire, which employed several theories of analytic philosophy of the mind, in order to determine which category the participants would belong to. These main categories were dualism, non-reductive materialism and reductive materialism. To test whether personality features affect preferences for these categories, the participants were investigated by Cloninger’s Temperament and Character Inventory (TCI). We found significant differences in the self-transcendence dimension of the TCI between participants who were evaluated as dualists and those who were assessed as reductive materialists. Our data show that the personality dimension of self-transcendence correlates with intuitive inclination toward reductive materialism or dualism. In addition, our results suggest that ideas, theories, and hypothetical solutions of the mind-body problem and possibly even conclusions, acceptance, and disputations of thought experiments of philosophy of the mind can be biased by personality traits. This fact should be taken into account in future discussions of the philosophy of the mind and may also be important for empirical research and an empirical understanding of the mind.
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Affiliation(s)
- Marek Havlík
- National Institute of Mental Health, Klecany, Czechia
| | | | | | - Jiří Horáček
- National Institute of Mental Health, Klecany, Czechia.,Third Faculty of Medicine, Charles University, Prague, Czechia
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11
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Esterlis I, Holmes SE, Sharma P, Krystal JH, DeLorenzo C. Metabotropic Glutamatergic Receptor 5 and Stress Disorders: Knowledge Gained From Receptor Imaging Studies. Biol Psychiatry 2018; 84:95-105. [PMID: 29100629 PMCID: PMC5858955 DOI: 10.1016/j.biopsych.2017.08.025] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 08/24/2017] [Accepted: 08/28/2017] [Indexed: 12/28/2022]
Abstract
The metabotropic glutamatergic receptor subtype 5 (mGluR5) may represent a promising therapeutic target for stress-related psychiatric disorders. Here, we describe mGluR5 findings in stress disorders, particularly major depressive disorder (MDD), highlighting insights from positron emission tomography studies. Positron emission tomography studies report either no differences or lower mGluR5 in MDD, potentially reflecting MDD heterogeneity. Unlike the rapidly acting glutamatergic agent ketamine, mGluR5-specific modulation has not yet shown antidepressant efficacy in MDD and bipolar disorder. Although we recently showed that ketamine may work, in part, through significant mGluR5 modulation, the specific role of mGluR5 downregulation in ketamine's antidepressant response is unclear. In contrast to MDD, there has been much less investigation of mGluR5 in bipolar disorder, yet initial studies indicate that mGluR5-specific treatments may aid in both depressed and manic mood states. The direction of modulation needed may be state dependent, however, limiting clinical feasibility. There has been relatively little study of posttraumatic stress disorder or obsessive-compulsive disorder to date, although there is evidence for the upregulation of mGluR5 in these disorders. However, while antagonism of mGluR5 may reduce fear conditioning, it may also reduce fear extinction. Therefore, studies are needed to determine the role mGluR5 modulation might play in the treatment of these conditions. Further challenges in modulating this prevalent neurotransmitter system include potential induction of significant side effects. As such, more research is needed to identify level and type (positive/negative allosteric modulation or full antagonism) of mGluR5 modulation required to translate existing knowledge into improved therapies.
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Affiliation(s)
- Irina Esterlis
- Department of Psychiatry, Yale University, New Haven, Connecticut; US Department of Veterans Affairs National Center for Posttraumatic Stress Disorder, Clinical Neurosciences Division, Veteran's Affairs Connecticut Healthcare System, West Haven, Connecticut.
| | | | - Priya Sharma
- Department of Psychiatry, Schulich School of Medicine and Dentistry; Western University- London, Ontario, Canada; London Health Sciences Centre- Victoria Hospital
| | - John H. Krystal
- Yale University, Department of Psychiatry,Yale University, Department of Neuroscience,U.S. Department of Veterans Affairs National Center for Posttraumatic Stress Disorder, Clinical Neurosciences Division, VA Connecticut Healthcare System
| | - Christine DeLorenzo
- Stony Brook University, Department of Psychiatry,Stony Brook University, Department of Biomedical Engineering
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12
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Leurquin-Sterk G, Ceccarini J, Crunelle CL, Weerasekera A, de Laat B, Himmelreich U, Bormans G, Van Laere K. Cerebral dopaminergic and glutamatergic transmission relate to different subjective responses of acute alcohol intake: an in vivo multimodal imaging study. Addict Biol 2018; 23:931-944. [PMID: 28884874 DOI: 10.1111/adb.12542] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 06/14/2017] [Accepted: 07/03/2017] [Indexed: 12/21/2022]
Abstract
Converging preclinical evidence links extrastriatal dopamine release and glutamatergic transmission via the metabotropic glutamate receptor 5 (mGluR5) to the rewarding properties of alcohol. To date, human evidence is lacking on how and where in the brain these processes occur. Mesocorticolimbic dopamine release upon intravenous alcohol administration and mGluR5 availability were measured in 11 moderate social drinkers by single-session [18 F]fallypride and [18 F]FPEB positron emission tomography, respectively. Additionally, baseline and postalcohol glutamate and glutamine levels in the anterior cingulate cortex (ACC) were measured by using proton-magnetic resonance spectroscopy. To investigate differences in reward domains linked to both neurotransmitters, regional imaging data were related to subjective alcohol responses. Alcohol induced significant [18 F]fallypride displacement in the prefrontal cortex (PFC), temporal and parietal cortices and thalamus (P < 0.05, corrected for multiple comparisons). Dopamine release in the ACC and orbitofrontal and ventromedial PFCs were correlated with subjective 'liking' and 'wanting' effects (P < 0.05). In contrast, baseline mGluR5 availability was positively correlated with the 'high' effect of alcohol in dorsolateral, ventrolateral and ventromedial PFCs and in the medial temporal lobe, thalamus and caudate nucleus (P < 0.05). Although neither proton-magnetic resonance spectroscopy glutamate nor glutamine levels were affected by alcohol, baseline ACC glutamate levels were negatively associated with the alcohol 'liking' effect (P < 0.003). These data reveal new mechanistic understanding and differential neurobiological underpinnings of the effects of acute alcohol consumption on human behavior. Specifically, prefrontal dopamine release may encode alcohol 'liking' and 'wanting' effects in specific areas underlying value processing and motivation, whereas mGluR5 availability in distinct prefrontal-temporal-subcortical regions is more related to the alcohol 'high' effect.
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Affiliation(s)
- Gil Leurquin-Sterk
- Department of Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology; University Hospitals Leuven; Belgium
| | - Jenny Ceccarini
- Department of Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology; University Hospitals Leuven; Belgium
| | - Cleo Lina Crunelle
- Toxicological Center, University of Antwerp, Department of Psychiatry; University Hospital Brussels; Belgium
| | | | - Bart de Laat
- Department of Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology; University Hospitals Leuven; Belgium
- MoSAIC, Molecular Small Animal Imaging Center; Belgium
| | - Uwe Himmelreich
- Department of Imaging and Pathology; Biomedical MRI/MoSAIC; Belgium
| | | | - Koen Van Laere
- Department of Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology; University Hospitals Leuven; Belgium
- MoSAIC, Molecular Small Animal Imaging Center; Belgium
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13
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Pakri Mohamed RM, Mokhtar MH, Yap E, Hanim A, Abdul Wahab N, Jaffar FHF, Kumar J. Ethanol-Induced Changes in PKCε: From Cell to Behavior. Front Neurosci 2018; 12:244. [PMID: 29706864 PMCID: PMC5907685 DOI: 10.3389/fnins.2018.00244] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 03/28/2018] [Indexed: 11/20/2022] Open
Abstract
The long-term binge intake of ethanol causes neuroadaptive changes that lead to drinkers requiring higher amounts of ethanol to experience its effects. This neuroadaptation can be partly attributed to the modulation of numerous neurotransmitter receptors by the various protein kinases C (PKCs). PKCs are enzymes that control cellular activities by regulating other proteins via phosphorylation. Among the various isoforms of PKC, PKCε is the most implicated in ethanol-induced biochemical and behavioral changes. Ethanol exposure causes changes to PKCε expression and localization in various brain regions that mediate addiction-favoring plasticity. Ethanol works in conjunction with numerous upstream kinases and second messenger activators to affect cellular PKCε expression. Chauffeur proteins, such as receptors for activated C kinase (RACKs), cause the translocation of PKCε to aberrant sites and mediate ethanol-induced changes. In this article, we aim to review the following: the general structure and function of PKCε, ethanol-induced changes in PKCε expression, the regulation of ethanol-induced PKCε activities in DAG-dependent and DAG-independent environments, the mechanisms underlying PKCε-RACKε translocation in the presence of ethanol, and the existing literature on the role of PKCε in ethanol-induced neurobehavioral changes, with the goal of creating a working model upon which further research can build.
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Affiliation(s)
| | - Mohd H. Mokhtar
- Department of Physiology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Ernie Yap
- Department of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Athirah Hanim
- Department of Physiology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Norhazlina Abdul Wahab
- Department of Physiology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Farah H. F. Jaffar
- Department of Physiology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Jaya Kumar
- Department of Physiology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
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14
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Stam D, Huang YA, Van den Stock J. Gray Matter Volume of a Region in the Thalamic Pulvinar Is Specifically Associated with Novelty Seeking. Front Psychol 2018. [PMID: 29535659 PMCID: PMC5835093 DOI: 10.3389/fpsyg.2018.00203] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Personality reflects the set of psychological traits and mechanisms characteristic for an individual. Geno-neuro-biologically inspired personality accounts have proposed a set of temperaments and characters that jointly compose personality profiles. The present study addresses the link between neurobiology and personality and investigates the association between temperament traits and regional gray matter volume. Furthermore, the specificity of these associations as well as the underlying components that drive the association are addressed. One hundred and four participants completed the Temperament and Character Inventory (TCI) and underwent structural magnetic resonance brain imaging. The participants included premanifest carriers of Huntington's disease, as this population is associated with temperament-related neuropsychiatric symptoms. Whole brain voxel-based multiple regression analyses on gray matter volume revealed a significant specific positive correlation between a region in the left thalamic pulvinar and novelty seeking score, controlled for the other traits (Pheight < 0.05, FWE-corrected). No significant associations were observed for the other temperament traits. Region of interest analyses showed that this association is driven by the subscale NS2: impulsiveness. The results increase the knowledge of the structural neurobiology of personality and indicate that individual differences in novelty seeking reflect the structural differences observed in the brain in an area that is widely and densely connected, which is in line with the typically domain-general behavioral influence of personality traits on a wide range of affective, perceptual, mnemotic, executive, and other cognitive functions.
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Affiliation(s)
- Daphne Stam
- Laboratory for Translational Neuropsychiatry, Department of Neuroscience, KU Leuven, Leuven, Belgium
| | - Yun-An Huang
- Laboratory for Translational Neuropsychiatry, Department of Neuroscience, KU Leuven, Leuven, Belgium
| | - Jan Van den Stock
- Laboratory for Translational Neuropsychiatry, Department of Neuroscience, KU Leuven, Leuven, Belgium.,Old Age Psychiatry, University Psychiatric Center KU Leuven, Leuven, Belgium.,Brain and Emotion Laboratory, Maastricht University, Maastricht, Netherlands
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15
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Leurquin-Sterk G, Ceccarini J, Crunelle CL, de Laat B, Verbeek J, Deman S, Neels H, Bormans G, Peuskens H, Van Laere K. Lower Limbic Metabotropic Glutamate Receptor 5 Availability in Alcohol Dependence. J Nucl Med 2018; 59:682-690. [PMID: 29348321 DOI: 10.2967/jnumed.117.199422] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 10/30/2017] [Indexed: 01/18/2023] Open
Abstract
Animal studies suggest an important role for the metabotropic glutamate receptor subtype 5 (mGlu5) in the pathophysiology of alcohol dependence, but direct human evidence is lacking. The goal of this study was to investigate cerebral mGlu5 availability in alcohol-dependent subjects versus controls using 18F-3-fluoro-5-[(pyridin-3-yl)ethynyl]benzonitrile (18F-FPEB) PET. Methods: Dynamic 90-min 18F-FPEB scans combined with arterial blood sampling were acquired for 16 recently abstinent alcohol-dependent subjects and 32 age-matched controls. Regional mGlu5 availability was quantified by the 18F-FPEB total distribution volume using both a voxel-by-voxel and a volume-of-interest analysis with partial-volume effect correction. Alcohol consumption within the last 3 mo was assessed by questionnaires and by hair ethyl glucuronide analysis. Craving was assessed using the Desire for Alcohol Questionnaire. Results: mGlu5 availability was lower in mainly limbic regions of alcohol-dependent subjects than in controls (P < 0.05, familywise error-corrected), ranging from 14% in the posterior cingulate cortex to 36% in the caudate nucleus. Lower mGlu5 availability was associated with higher hair ethyl glucuronide levels for most regions and was related to a lower level of craving specifically in the middle frontal gyrus, cingulate cortex, and inferolateral temporal lobe. Conclusion: These findings provide human in vivo evidence that limbic mGlu5 has a role in the pathophysiology of alcohol dependence, possibly involved in a compensatory mechanism helping to reduce craving during abstinence.
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Affiliation(s)
- Gil Leurquin-Sterk
- Division of Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Jenny Ceccarini
- Division of Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Cleo L Crunelle
- Toxicological Center, University of Antwerp, Wilrijk, Belgium.,Department of Psychiatry, University Hospital Brussels, Brussels, Belgium
| | - Bart de Laat
- Division of Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium.,MoSAIC: Molecular Small Animal Imaging Center, KU Leuven, Leuven, Belgium
| | - Jef Verbeek
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Stephanie Deman
- Genomics Core, UZ Leuven, and Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Hugo Neels
- Toxicological Center, University of Antwerp, Wilrijk, Belgium
| | - Guy Bormans
- Laboratory for Radiopharmacy, KU Leuven, Leuven, Belgium; and
| | - Hendrik Peuskens
- University Psychiatric Center, KU Leuven, Kortenberg, and Kliniek Broeders Alexianen, Tienen, Belgium
| | - Koen Van Laere
- Division of Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium.,MoSAIC: Molecular Small Animal Imaging Center, KU Leuven, Leuven, Belgium
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16
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Altered metabotropic glutamate receptor 5 markers in PTSD: In vivo and postmortem evidence. Proc Natl Acad Sci U S A 2017; 114:8390-8395. [PMID: 28716937 DOI: 10.1073/pnas.1701749114] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Posttraumatic stress disorder (PTSD) is a prevalent and highly disabling disorder, but there is currently no targeted pharmacological treatment for it. Dysfunction of the glutamate system has been implicated in trauma and stress psychopathology, resulting in a growing interest in modulation of the glutamate system for the treatment of PTSD. Specifically, the metabotropic glutamate receptor 5 (mGluR5) represents a promising treatment target. We used [18F]FPEB, a radioligand that binds to the mGluR5, and positron emission tomography (PET) to quantify in vivo mGluR5 availability in human PTSD vs. healthy control (HCs) subjects. In an independent sample of human postmortem tissue, we investigated expression of proteins that have a functional relationship with mGluR5 and glucocorticoids in PTSD. We observed significantly higher cortical mGluR5 availability in PTSD in vivo and positive correlations between mGluR5 availability and avoidance symptoms. In the postmortem sample, we observed up-regulation of SHANK1, a protein that anchors mGluR5 to the cell surface, as well as decreased expression of FKBP5, implicating aberrant glucocorticoid functioning in PTSD. Results of this study provide insight into molecular mechanisms underlying PTSD and suggest that mGluR5 may be a promising target for mechanism-based treatments aimed at mitigating this disorder.
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17
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Chiamulera C, Marzo CM, Balfour DJK. Metabotropic glutamate receptor 5 as a potential target for smoking cessation. Psychopharmacology (Berl) 2017; 234:1357-1370. [PMID: 27847973 DOI: 10.1007/s00213-016-4487-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 11/07/2016] [Indexed: 12/21/2022]
Abstract
RATIONALE Most habitual smokers find it difficult to quit smoking because they are dependent upon the nicotine present in tobacco smoke. Tobacco dependence is commonly treated pharmacologically using nicotine replacement therapy or drugs, such as varenicline, that target the nicotinic receptor. Relapse rates, however, remain high, and there remains a need to develop novel non-nicotinic pharmacotherapies for the dependence that are more effective than existing treatments. OBJECTIVE The purpose of this paper is to review the evidence from preclinical and clinical studies that drugs that antagonise the metabotropic glutamate receptor 5 (mGluR5) in the brain are likely to be efficacious as treatments for tobacco dependence. RESULTS Imaging studies reveal that chronic exposure to tobacco smoke reduces the density of mGluR5s in human brain. Preclinical results demonstrate that negative allosteric modulators (NAMs) at mGluR5 attenuate both nicotine self-administration and the reinstatement of responding evoked by exposure to conditioned cues paired with nicotine delivery. They also attenuate the effects of nicotine on brain dopamine pathways implicated in addiction. CONCLUSIONS Although mGluR5 NAMs attenuate most of the key facets of nicotine dependence, they potentiate the symptoms of nicotine withdrawal. This may limit their value as smoking cessation aids. The NAMs that have been employed most widely in preclinical studies of nicotine dependence have too many "off-target" effects to be used clinically. However, newer mGluR5 NAMs have been developed for clinical use in other indications. Future studies will determine if these agents can also be used effectively and safely to treat tobacco dependence.
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Affiliation(s)
- Cristiano Chiamulera
- Neuropsychopharmacology Lab., Section Pharmacology, Department Diagnostic and Public Health, University of Verona, P.le Scuro 10, 37134, Verona, Italy.
| | - Claudio Marcello Marzo
- Neuropsychopharmacology Lab., Section Pharmacology, Department Diagnostic and Public Health, University of Verona, P.le Scuro 10, 37134, Verona, Italy
| | - David J K Balfour
- Division of Neuroscience, University of Dundee Medical School, Mailbox 6, Ninewells Hospital, Dundee, DD1 9SY, UK
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