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Prasad K, de Vries EFJ, Sijbesma JWA, Garcia-Varela L, Vazquez-Matias DA, Moraga-Amaro R, Willemsen ATM, Dierckx RAJO, van Waarde A. Impact of an Adenosine A 2A Receptor Agonist and Antagonist on Binding of the Dopamine D 2 Receptor Ligand [ 11C]raclopride in the Rodent Striatum. Mol Pharm 2022; 19:2992-3001. [PMID: 35849844 PMCID: PMC9346611 DOI: 10.1021/acs.molpharmaceut.2c00450] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Adenosine A2A and dopamine D2 receptors in the basal ganglia form heterotetrameric structures that are involved in the regulation of motor activity and neuropsychiatric functions. The present study examines the A2A receptor-mediated modulation of D2 receptor binding in vivo using positron emission tomography (PET) with the D2 antagonist tracer [11C]raclopride. Healthy male Wistar rats (n = 8) were scanned (60 min dynamic scan) with [11C]raclopride at baseline and 7 days later following an acute administration of the A2A agonist CGS21680 (1 mg/kg), using a MicroPET Focus-220 camera. Nondisplaceable binding potential (BPND) values were calculated using a simplified reference tissue model (SRTM), with cerebellum as the reference tissue. SRTM analysis did not show any significant changes in [11C]raclopride BPND (p = 0.102) in striatum after CGS21680 administration compared to the baseline. As CGS21680 strongly affects hemodynamics, we also used arterial blood sampling and a metabolite-corrected plasma input function for compartment modeling using the reversible two-tissue compartment model (2TCM) to obtain the BPND from the k3/k4 ratio and from the striatum/cerebellum volume of distribution ratio (DVR) in a second group of animals. These rats underwent dynamic [11C]raclopride scans after pretreatment with a vehicle (n = 5), a single dose of CGS21680 (1 mg/kg, n = 5), or a single dose of the A2A antagonist KW6002 (1 mg/kg, n = 5). The parent fraction in plasma was significantly higher in the CGS21680-treated group (p = 0.0001) compared to the vehicle-treated group. GCS21680 administration significantly reduced the striatal k3/k4 ratio (p < 0.01), but k3 and k4 estimates may be less reliable. The BPND (DVR-1) decreased from 1.963 ± 0.27 in the vehicle-treated group to 1.53 ± 0.55 (p = 0.080) or 1.961 ± 0.11 (p = 0.993) after the administration of CGS21680 or KW6002, respectively. Our study suggests that the A2A agonist CGS21680, but not the antagonist KW6002, may reduce the D2 receptor availability in the striatum.
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Affiliation(s)
- Kavya Prasad
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9713 GZ Groningen, The Netherlands
| | - Erik F J de Vries
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9713 GZ Groningen, The Netherlands
| | - Jürgen W A Sijbesma
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9713 GZ Groningen, The Netherlands
| | - Lara Garcia-Varela
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9713 GZ Groningen, The Netherlands
| | - Daniel A Vazquez-Matias
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9713 GZ Groningen, The Netherlands
| | - Rodrigo Moraga-Amaro
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9713 GZ Groningen, The Netherlands
| | - Antoon T M Willemsen
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9713 GZ Groningen, The Netherlands
| | - Rudi A J O Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9713 GZ Groningen, The Netherlands
| | - Aren van Waarde
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9713 GZ Groningen, The Netherlands
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Mach RH, Luedtke RR. Challenges in the development of dopamine D2- and D3-selective radiotracers for PET imaging studies. J Labelled Comp Radiopharm 2017; 61:291-298. [PMID: 28857231 DOI: 10.1002/jlcr.3558] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 08/24/2017] [Accepted: 08/25/2017] [Indexed: 12/11/2022]
Abstract
The dopamine D2-like receptors (ie, D2/3 receptors) have been the most extensively studied CNS receptor with Positron Emission Tomography (PET). The 3 different radiotracers that have been used in these studies are [11 C]raclopride, [18 F]fallypride, and [11 C]PHNO. Because these radiotracers have a high affinity for both dopamine D2 and D3 receptors, the density of dopamine receptors in the CNS is reported as the D2/3 binding potential, which reflects a measure of the density of both receptor subtypes. Although the development of D2- and D3-selective PET radiotracers has been an active area of research for many years, this by and large presents an unmet need in the area of translational PET imaging studies. This article discusses some of the challenges that have inhibited progress in this area of research and the current status of the development of subtype selective radiotracers for imaging D3 and D2 dopamine receptors with PET.
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Affiliation(s)
- Robert H Mach
- Department of Radiology, Perelman School Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Robert R Luedtke
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center-Fort Worth, Fort Worth, TX, USA
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Schain M, Fazio P, Mrzljak L, Amini N, Al-Tawil N, Fitzer-Attas C, Bronzova J, Landwehrmeyer B, Sampaio C, Halldin C, Varrone A. Revisiting the Logan plot to account for non-negligible blood volume in brain tissue. EJNMMI Res 2017; 7:66. [PMID: 28822101 PMCID: PMC5561763 DOI: 10.1186/s13550-017-0314-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 08/08/2017] [Indexed: 11/23/2022] Open
Abstract
Background Reference tissue-based quantification of brain PET data does not typically include correction for signal originating from blood vessels, which is known to result in biased outcome measures. The bias extent depends on the amount of radioactivity in the blood vessels. In this study, we seek to revisit the well-established Logan plot and derive alternative formulations that provide estimation of distribution volume ratios (DVRs) that are corrected for the signal originating from the vasculature. Results New expressions for the Logan plot based on arterial input function and reference tissue were derived, which included explicit terms for whole blood radioactivity. The new methods were evaluated using PET data acquired using [11C]raclopride and [18F]MNI-659. The two-tissue compartment model (2TCM), with which signal originating from blood can be explicitly modeled, was used as a gold standard. DVR values obtained for [11C]raclopride using the either blood-based or reference tissue-based Logan plot were systematically underestimated compared to 2TCM, and for [18F]MNI-659, a proportionality bias was observed, i.e., the bias varied across regions. The biases disappeared when optimal blood-signal correction was used for respective tracer, although for the case of [18F]MNI-659 a small but systematic overestimation of DVR was still observed. Conclusions The new method appears to remove the bias introduced due to absence of correction for blood volume in regular graphical analysis and can be considered in clinical studies. Further studies are however required to derive a generic mapping between plasma and whole-blood radioactivity levels. Electronic supplementary material The online version of this article (doi:10.1186/s13550-017-0314-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Martin Schain
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden.
| | - Patrik Fazio
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | | | - Nahid Amini
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Nabil Al-Tawil
- Karolinska Trial Alliance, Karolinska University Hospital, M62, SE-141-86, Stockholm, Sweden
| | | | | | | | | | - Christer Halldin
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Andrea Varrone
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
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Eisenstein SA, Bogdan R, Chen L, Moerlein SM, Black KJ, Perlmutter JS, Hershey T, Barch DM. Preliminary evidence that negative symptom severity relates to multilocus genetic profile for dopamine signaling capacity and D2 receptor binding in healthy controls and in schizophrenia. J Psychiatr Res 2017; 86:9-17. [PMID: 27886638 PMCID: PMC5272837 DOI: 10.1016/j.jpsychires.2016.11.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 10/07/2016] [Accepted: 11/15/2016] [Indexed: 12/31/2022]
Abstract
Deficits in central, subcortical dopamine (DA) signaling may underlie negative symptom severity, particularly anhedonia, in healthy individuals and in schizophrenia. To investigate these relationships, we assessed negative symptoms with the Schedule for the Assessment of Negative Symptoms and the Brief Negative Symptom Scale (BNSS) and self-reported anhedonia with the Scales for Physical and Social Anhedonia (SPSA), Temporal Experience of Pleasure Scale, and Snaith-Hamilton Pleasure Scale in 36 healthy controls (HC), 27 siblings (SIB) of individuals with schizophrenia, and 66 individuals with schizophrenia or schizoaffective disorder (SCZ). A subset of participants (N = 124) were genotyped for DA-related polymorphisms in genes for DRD4, DRD2/ANKK1, DAT1, and COMT, which were used to construct biologically-informed multi-locus genetic profile (MGP) scores reflective of subcortical dopaminergic signaling. DA receptor type 2 (D2R) binding was assessed among a second subset of participants (N = 23) using PET scans with the D2R-selective, non-displaceable radioligand (N-[11C]methyl)benperidol. Higher MGP scores, reflecting elevated subcortical dopaminergic signaling capacity, were associated with less negative symptom severity, as measured by the BNSS, across all participants. In addition, higher striatal D2R binding was associated with less physical and social anhedonia, as measured by the SPSA, across HC, SIB, and SCZ. The current preliminary findings support the hypothesis that subcortical DA function may contribute to negative symptom severity and self-reported anhedonia, independent of diagnostic status.
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Affiliation(s)
- Sarah A. Eisenstein
- Psychiatry Department, Washington University School of Medicine, St. Louis, MO, USA,Radiology Department, Washington University School of Medicine, St. Louis, MO, USA,Corresponding author, Sarah A. Eisenstein, Psychiatry Department, Campus Box 8225, Washington University School of Medicine, St. Louis, MO 63110, Phone: (314) 362-7107, Fax: (314) 362-0168,
| | - Ryan Bogdan
- Psychological & Brain Sciences Department, Washington University in St. Louis, St. Louis, MO, USA.
| | - Ling Chen
- Division of Biostatistics, Washington University School of Medicine, St. Louis, MO, USA.
| | - Stephen M. Moerlein
- Radiology Department, Washington University School of Medicine, St. Louis, MO, USA,Biochemistry Department, Washington University School of Medicine, St. Louis, MO, USA
| | - Kevin J. Black
- Psychiatry Department, Washington University School of Medicine, St. Louis, MO, USA,Radiology Department, Washington University School of Medicine, St. Louis, MO, USA,Neurology Department, Washington University School of Medicine, St. Louis, MO, USA,Neuroscience Department, Washington University School of Medicine, MO, USA
| | - Joel S. Perlmutter
- Radiology Department, Washington University School of Medicine, St. Louis, MO, USA,Biochemistry Department, Washington University School of Medicine, St. Louis, MO, USA,Programs in Physical Therapy and Occupational Therapy, Washington University School of Medicine, St. Louis, MO, USA
| | - Tamara Hershey
- Psychiatry Department, Washington University School of Medicine, St. Louis, MO, USA; Radiology Department, Washington University School of Medicine, St. Louis, MO, USA; Psychological & Brain Sciences Department, Washington University in St. Louis, St. Louis, MO, USA; Neurology Department, Washington University School of Medicine, St. Louis, MO, USA.
| | - Deanna M. Barch
- Psychiatry Department, Washington University School of Medicine, St. Louis, MO, USA,Radiology Department, Washington University School of Medicine, St. Louis, MO, USA,Psychological & Brain Sciences Department, Washington University in St. Louis, St. Louis, MO, USA
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Schain M, Zanderigo F, Mann J, Ogden R. Estimation of the binding potential BPND without a reference region or blood samples for brain PET studies. Neuroimage 2017; 146:121-131. [PMID: 27856316 DOI: 10.1016/j.neuroimage.2016.11.035] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 11/13/2016] [Indexed: 02/02/2023] Open
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6
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Eisenstein SA, Bogdan R, Love-Gregory L, Corral-Frías NS, Koller JM, Black KJ, Moerlein SM, Perlmutter JS, Barch DM, Hershey T. Prediction of striatal D2 receptor binding by DRD2/ANKK1 TaqIA allele status. Synapse 2016; 70:418-31. [PMID: 27241797 DOI: 10.1002/syn.21916] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 05/26/2016] [Accepted: 05/27/2016] [Indexed: 01/04/2023]
Abstract
In humans, the A1 (T) allele of the dopamine (DA) D2 receptor/ankyrin repeat and kinase domain containing 1 (DRD2/ANKK1) TaqIA (rs1800497) single nucleotide polymorphism has been associated with reduced striatal DA D2/D3 receptor (D2/D3R) availability. However, radioligands used to estimate D2/D3R are displaceable by endogenous DA and are nonselective for D2R, leaving the relationship between TaqIA genotype and D2R specific binding uncertain. Using the positron emission tomography (PET) radioligand, (N-[(11) C]methyl)benperidol ([(11) C]NMB), which is highly selective for D2R over D3R and is not displaceable by endogenous DA, the current study examined whether DRD2/ANKK1 TaqIA genotype predicts D2R specific binding in two independent samples. Sample 1 (n = 39) was composed of obese and nonobese adults; sample 2 (n = 18) was composed of healthy controls, unmedicated individuals with schizophrenia, and siblings of individuals with schizophrenia. Across both samples, A1 allele carriers (A1+) had 5 to 12% less striatal D2R specific binding relative to individuals homozygous for the A2 allele (A1-), regardless of body mass index or diagnostic group. This reduction is comparable to previous PET studies of D2/D3R availability (10-14%). The pooled effect size for the difference in total striatal D2R binding between A1+ and A1- was large (0.84). In summary, in line with studies using displaceable D2/D3R radioligands, our results indicate that DRD2/ANKK1 TaqIA allele status predicts striatal D2R specific binding as measured by D2R-selective [(11) C]NMB. These findings support the hypothesis that DRD2/ANKK1 TaqIA allele status may modify D2R, perhaps conferring risk for certain disease states.
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Affiliation(s)
- Sarah A Eisenstein
- Department of Psychiatry, Washington University in St. Louis, St. Louis, MO, 63110.,Department of Radiology, Washington University in St. Louis, St. Louis, MO, 63110
| | - Ryan Bogdan
- Department of Psychological & Brain Sciences, Washington University in St. Louis, St. Louis, MO, 63130
| | - Latisha Love-Gregory
- Department of Medicine, Washington University in St. Louis, St. Louis, MO, 63110
| | - Nadia S Corral-Frías
- Department of Psychiatry, Washington University in St. Louis, St. Louis, MO, 63110
| | - Jonathan M Koller
- Department of Psychiatry, Washington University in St. Louis, St. Louis, MO, 63110
| | - Kevin J Black
- Department of Psychiatry, Washington University in St. Louis, St. Louis, MO, 63110.,Department of Radiology, Washington University in St. Louis, St. Louis, MO, 63110.,Department of Neurology, Washington University in St. Louis, St. Louis, MO, 63110.,Department of Neuroscience, Washington University in St. Louis, St. Louis, MO, 63110
| | - Stephen M Moerlein
- Department of Radiology, Washington University in St. Louis, St. Louis, MO, 63110.,Department of Biochemistry, Washington University in St. Louis, St. Louis, MO, 63110
| | - Joel S Perlmutter
- Department of Radiology, Washington University in St. Louis, St. Louis, MO, 63110.,Department of Neurology, Washington University in St. Louis, St. Louis, MO, 63110.,Programs in Physical Therapy and Occupational Therapy, Washington University in St. Louis, St. Louis, MO, 63110
| | - Deanna M Barch
- Department of Psychiatry, Washington University in St. Louis, St. Louis, MO, 63110.,Department of Radiology, Washington University in St. Louis, St. Louis, MO, 63110.,Department of Psychological & Brain Sciences, Washington University in St. Louis, St. Louis, MO, 63130
| | - Tamara Hershey
- Department of Psychiatry, Washington University in St. Louis, St. Louis, MO, 63110.,Department of Radiology, Washington University in St. Louis, St. Louis, MO, 63110.,Department of Psychological & Brain Sciences, Washington University in St. Louis, St. Louis, MO, 63130.,Department of Neurology, Washington University in St. Louis, St. Louis, MO, 63110
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Eisenstein SA, Gredysa DM, Antenor–Dorsey JA, Green L, Arbeláez AM, Koller JM, Black KJ, Perlmutter JS, Moerlein SM, Hershey T. Insulin, Central Dopamine D2 Receptors, and Monetary Reward Discounting in Obesity. PLoS One 2015; 10:e0133621. [PMID: 26192187 PMCID: PMC4507849 DOI: 10.1371/journal.pone.0133621] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 06/30/2015] [Indexed: 12/19/2022] Open
Abstract
Animal research finds that insulin regulates dopamine signaling and reward behavior, but similar research in humans is lacking. We investigated whether individual differences in body mass index, percent body fat, pancreatic β-cell function, and dopamine D2 receptor binding were related to reward discounting in obese and non-obese adult men and women. Obese (n = 27; body mass index>30) and non-obese (n = 20; body mass index<30) adults were assessed for percent body fat with dual-energy X-ray absorptiometry and for β-cell function using disposition index. Choice of larger, but delayed or less certain, monetary rewards relative to immediate, certain smaller monetary rewards was measured using delayed and probabilistic reward discounting tasks. Positron emission tomography using a non-displaceable D2-specific radioligand, [11C](N-methyl)benperidol quantified striatal D2 receptor binding. Groups differed in body mass index, percent body fat, and disposition index, but not in striatal D2 receptor specific binding or reward discounting. Higher percent body fat in non-obese women related to preference for a smaller, certain reward over a larger, less likely one (greater probabilistic discounting). Lower β-cell function in the total sample and lower insulin sensitivity in obese related to stronger preference for an immediate and smaller monetary reward over delayed receipt of a larger one (greater delay discounting). In obese adults, higher striatal D2 receptor binding related to greater delay discounting. Interestingly, striatal D2 receptor binding was not significantly related to body mass index, percent body fat, or β-cell function in either group. Our findings indicate that individual differences in percent body fat, β-cell function, and striatal D2 receptor binding may each contribute to altered reward discounting behavior in non-obese and obese individuals. These results raise interesting questions about whether and how striatal D2 receptor binding and metabolic factors, including β-cell function, interact to affect reward discounting in humans.
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Affiliation(s)
- Sarah A. Eisenstein
- Psychiatry Department, Washington University in St. Louis, St. Louis, MO, United States of America
- Radiology Department, Washington University in St. Louis, St. Louis, MO, United States of America
| | - Danuta M. Gredysa
- Psychology Department, Washington University in St. Louis, St. Louis, MO, United States of America
| | - Jo Ann Antenor–Dorsey
- Psychiatry Department, Washington University in St. Louis, St. Louis, MO, United States of America
| | - Leonard Green
- Psychology Department, Washington University in St. Louis, St. Louis, MO, United States of America
| | - Ana Maria Arbeláez
- Pediatrics Department, Washington University in St. Louis, St. Louis, MO, United States of America
| | - Jonathan M. Koller
- Psychiatry Department, Washington University in St. Louis, St. Louis, MO, United States of America
| | - Kevin J. Black
- Psychiatry Department, Washington University in St. Louis, St. Louis, MO, United States of America
- Radiology Department, Washington University in St. Louis, St. Louis, MO, United States of America
- Neurology Department, Washington University in St. Louis, St. Louis, MO, United States of America
- Anatomy and Neurobiology Department, Washington University in St. Louis, St. Louis, MO, United States of America
| | - Joel S. Perlmutter
- Radiology Department, Washington University in St. Louis, St. Louis, MO, United States of America
- Neurology Department, Washington University in St. Louis, St. Louis, MO, United States of America
- Anatomy and Neurobiology Department, Washington University in St. Louis, St. Louis, MO, United States of America
- Programs in Physical Therapy and Occupational Therapy, Washington University in St. Louis, St. Louis, MO, United States of America
| | - Stephen M. Moerlein
- Radiology Department, Washington University in St. Louis, St. Louis, MO, United States of America
- Biochemistry and Molecular Biophysics Department, Washington University in St. Louis, St. Louis, MO, United States of America
| | - Tamara Hershey
- Psychiatry Department, Washington University in St. Louis, St. Louis, MO, United States of America
- Radiology Department, Washington University in St. Louis, St. Louis, MO, United States of America
- Neurology Department, Washington University in St. Louis, St. Louis, MO, United States of America
- * E-mail:
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8
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Eisenstein SA, Antenor-Dorsey JAV, Gredysa DM, Koller JM, Bihun EC, Ranck SA, Arbeláez AM, Klein S, Perlmutter JS, Moerlein SM, Black KJ, Hershey T. A comparison of D2 receptor specific binding in obese and normal-weight individuals using PET with (N-[(11)C]methyl)benperidol. Synapse 2013; 67:748-56. [PMID: 23650017 PMCID: PMC3778147 DOI: 10.1002/syn.21680] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 04/20/2013] [Accepted: 04/27/2013] [Indexed: 01/11/2023]
Abstract
Previous PET imaging studies have demonstrated mixed findings regarding dopamine D2/D3 receptor availability in obese relative to nonobese humans. Nonspecific D2/D3 radioligands do not allow for separate estimation of D2 receptor (D2R) and D3 receptor (D3R) subtypes of the D2 receptor family, which may play different roles in behavior and are distributed differently throughout the brain. These radioligands are also displaceable by endogenous dopamine, confounding interpretation of differences in receptor availability with differing levels of dopamine release. The present study used PET imaging with the D2R-selective radioligand (N-[(11)C] methyl)benperidol ([(11)C]NMB), which is nondisplaceable by endogenous dopamine, to estimate D2R specific binding (BPND) and its relationship to body mass index (BMI) and age in 15 normal-weight (mean BMI = 22.6 kg/m(2)) and 15 obese (mean BMI = 40.3 kg/m(2)) men and women. Subjects with illnesses or taking medications that interfere with dopamine signaling were excluded. Striatal D2R BPND was calculated using the Logan graphical method with cerebellum as a reference region. D2R BPND estimates were higher in putamen and caudate relative to nucleus accumbens, but did not differ between normal-weight and obese groups. BMI values did not correlate with D2R BPND . Age was negatively correlated with putamen D2R BPND in both groups. These results suggest that altered D2R specific binding is not involved in the pathogenesis of obesity per se and underscore the need for additional studies evaluating the relationship between D3R, dopamine reuptake, or endogenous dopamine release and human obesity.
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Affiliation(s)
- Sarah A. Eisenstein
- Department of Psychiatry, Washington University School of Medicine in St. Louis, 660 S. Euclid Ave., St. Louis, MO 63110
| | - Jo Ann V. Antenor-Dorsey
- Department of Psychiatry, Washington University School of Medicine in St. Louis, 660 S. Euclid Ave., St. Louis, MO 63110
| | - Danuta M. Gredysa
- Department of Psychiatry, Washington University School of Medicine in St. Louis, 660 S. Euclid Ave., St. Louis, MO 63110
| | - Jonathan M. Koller
- Department of Psychiatry, Washington University School of Medicine in St. Louis, 660 S. Euclid Ave., St. Louis, MO 63110
| | - Emily C. Bihun
- Department of Psychiatry, Washington University School of Medicine in St. Louis, 660 S. Euclid Ave., St. Louis, MO 63110
| | - Samantha A. Ranck
- Department of Psychiatry, Washington University School of Medicine in St. Louis, 660 S. Euclid Ave., St. Louis, MO 63110
| | - Ana Maria Arbeláez
- Department of Pediatrics, Washington University School of Medicine in St. Louis, 660 S. Euclid Ave., St. Louis, MO 63110
| | - Samuel Klein
- Department of Internal Medicine, Washington University School of Medicine in St. Louis, 660 S. Euclid Ave., St. Louis, MO 63110
| | - Joel S. Perlmutter
- Department of Neurology, Washington University School of Medicine in St. Louis, 660 S. Euclid Ave., St. Louis, MO 63110
- Department of Radiology, Washington University School of Medicine in St. Louis, Mallinckrodt Institute of Radiology, 660 S. Euclid Ave., St. Louis, MO 63110
- Department of Anatomy and Neurobiology, Washington University School of Medicine in St. Louis, 660 S. Euclid Ave., St. Louis, MO 63110
- Program in Physical Therapy, Washington University School of Medicine in St. Louis, 4444 Forest Park Blvd., St. Louis, MO 63108
- Program in Occupational Therapy, Washington University School of Medicine in St. Louis, 4444 Forest Park Blvd., St. Louis, MO 63108
| | - Stephen M. Moerlein
- Department of Radiology, Washington University School of Medicine in St. Louis, Mallinckrodt Institute of Radiology, 660 S. Euclid Ave., St. Louis, MO 63110
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine in St. Louis, 660 S. Euclid Ave., St. Louis, MO 63110
| | - Kevin J. Black
- Department of Psychiatry, Washington University School of Medicine in St. Louis, 660 S. Euclid Ave., St. Louis, MO 63110
- Department of Neurology, Washington University School of Medicine in St. Louis, 660 S. Euclid Ave., St. Louis, MO 63110
- Department of Radiology, Washington University School of Medicine in St. Louis, Mallinckrodt Institute of Radiology, 660 S. Euclid Ave., St. Louis, MO 63110
- Department of Anatomy and Neurobiology, Washington University School of Medicine in St. Louis, 660 S. Euclid Ave., St. Louis, MO 63110
| | - Tamara Hershey
- Department of Psychiatry, Washington University School of Medicine in St. Louis, 660 S. Euclid Ave., St. Louis, MO 63110
- Department of Neurology, Washington University School of Medicine in St. Louis, 660 S. Euclid Ave., St. Louis, MO 63110
- Department of Radiology, Washington University School of Medicine in St. Louis, Mallinckrodt Institute of Radiology, 660 S. Euclid Ave., St. Louis, MO 63110
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Eisenstein SA, Koller JM, Piccirillo M, Kim A, Antenor-Dorsey JAV, Videen TO, Snyder AZ, Karimi M, Moerlein SM, Black KJ, Perlmutter JS, Hershey T. Characterization of extrastriatal D2 in vivo specific binding of [¹⁸F](N-methyl)benperidol using PET. Synapse 2012; 66:770-80. [PMID: 22535514 DOI: 10.1002/syn.21566] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 04/16/2012] [Accepted: 04/17/2012] [Indexed: 12/25/2022]
Abstract
PET imaging studies of the role of the dopamine D2 receptor family in movement and neuropsychiatric disorders are limited by the use of radioligands that have near-equal affinities for D2 and D3 receptor subtypes and are susceptible to competition with endogenous dopamine. By contrast, the radioligand [¹⁸F]N-methylbenperidol ([¹⁸F]NMB) has high selectivity and affinity for the D2 receptor subtype (D2R) and is not sensitive to endogenous dopamine. Although [¹⁸F]NMB has high binding levels in striatum, its utility for measuring D2R in extrastriatal regions is unknown. A composite MR-PET image was constructed across 14 healthy adult participants representing average NMB uptake 60 to 120 min after [¹⁸F]NMB injection. Regional peak radioactivity was identified using a peak-finding algorithm. FreeSurfer and manual tracing identified a priori regions of interest (ROI) on each individual's MR image and tissue activity curves were extracted from coregistered PET images. [¹⁸F]NMB binding potentials (BP(ND) s) were calculated using the Logan graphical method with cerebellum as reference region. In eight unique participants, extrastriatal BP(ND) estimates were compared between Logan graphical methods and a three-compartment kinetic tracer model. Radioactivity and BP(ND) levels were highest in striatum, lower in extrastriatal subcortical regions, and lowest in cortical regions relative to cerebellum. Age negatively correlated with striatal BP(ND) s. BP(ND) estimates for extrastriatal ROIs were highly correlated across kinetic and graphical methods. Our findings indicate that PET with [¹⁸F]NMB measures specific binding in extrastriatal regions, making it a viable radioligand to study extrastriatal D2R levels in healthy and diseased states.
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Affiliation(s)
- Sarah A Eisenstein
- Department of Psychiatry, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110, USA
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Karimi M, Moerlein SM, Videen TO, Luedtke RR, Taylor M, Mach RH, Perlmutter JS. Decreased striatal dopamine receptor binding in primary focal dystonia: a D2 or D3 defect? Mov Disord 2010; 26:100-6. [PMID: 20960437 DOI: 10.1002/mds.23401] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Revised: 06/22/2010] [Accepted: 07/25/2010] [Indexed: 11/11/2022] Open
Abstract
Dystonia is an involuntary movement disorder characterized by repetitive patterned or sustained muscle contractions causing twisting or abnormal postures. Several lines of evidence suggest that abnormalities of dopaminergic pathways contribute to the pathophysiology of dystonia. In particular, dysfunction of D2-like receptors that mediate function of the indirect pathway in the basal ganglia may play a key role. We have demonstrated with positron emission tomography that patients with primary focal cranial or hand dystonia have reduced putamenal specific binding of [(18)F]spiperone, a nonselective D2-like radioligand with nearly equal affinity for serotonergic 5-HT(2A) sites. We then repeated the study with [(18)F]N-methyl-benperidol (NMB), a more selective D2-like receptor radioligand with minimal affinity for 5-HT(2A). Surprisingly, there was no decrease in NMB binding in the putamen of subjects with dystonia. Our findings excluded reductions of putamenal uptake greater than 20% with 95% confidence intervals. The analysis of the in vitro selectivity of NMB and spiperone demonstrated that NMB was highly selective for D2 receptors relative to D3 receptors (200-fold difference in affinity), whereas spiperone has similar affinity for all three of the D2-like receptor subtypes. These findings when coupled with other literature suggest that a defect in D3, rather than D2, receptor expression may be associated with primary focal dystonia.
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Affiliation(s)
- Morvarid Karimi
- Department of Neurology, Washington University School of Medicine, Saint Louis, Missouri 63110-1093, USA.
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