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Caravaggio F, Porco N, Kim J, Torres-Carmona E, Brown E, Iwata Y, Nakajima S, Gerretsen P, Remington G, Graff-Guerrero A. Measuring amphetamine-induced dopamine release in humans: A comparative meta-analysis of [ 11 C]-raclopride and [ 11 C]-(+)- PHNO studies. Synapse 2021; 75:e22195. [PMID: 33471400 DOI: 10.1002/syn.22195] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/02/2021] [Accepted: 01/13/2021] [Indexed: 02/06/2023]
Abstract
The radiotracers [11 C]-raclopride and [11 C]-(+)-PHNO are commonly used to measure differences in amphetamine-induced dopamine release between healthy persons and persons with neuropsychiatric diseases. As an agonist radiotracer, [11 C]-(+)-PHNO should theoretically be roughly 2.7 times more sensitive to displacement by endogenous dopamine than [11 C]raclopride. To date, only one study has been published comparing the sensitivity of these two radiotracers to amphetamine-induced dopamine release in healthy persons. Unfortunately, conflicting findings in the literature suggests that the dose of amphetamine they employed (0.3 mg/kg, p.o.) may not reliably reduce [11 C]-raclopride binding in the caudate. Thus, it is unclear whether the preponderance of evidence supports the theory that [11 C]-(+)-PHNO is more sensitive to displacement by amphetamine in humans than [11 C]-raclopride. In order to clarify these issues, we conducted a comparative meta-analysis summarizing the effects of amphetamine on [11 C]-raclopride and [11 C]-(+)-PHNO binding in healthy humans. Our analysis indicates that amphetamine given at 0.3 mg/kg, p.o. does not reliably reduce [11 C]-raclopride binding in the caudate. Second, the greater sensitivity of [11 C]-(+)-PHNO is evidenced at 0.5 mg/kg, p.o., but not at lower doses of amphetamine. Third, our analysis suggests that [11 C]-(+)-PHNO may be roughly 1.5 to 2.5 times more sensitive to displacement by amphetamine than [11 C]-raclopride in healthy persons. We recommend that future displacement studies with these radiotracers employ 0.5 mg/kg, p.o. of amphetamine with a dose, post-scan interval of at least 3 hr. Using this dose of amphetamine, [11 C]-raclopride studies should employ at least n = 34 participants per group, while [11 C]-(+)-PHNO studies should employ at least n = 6 participants per group, in order to be sufficiently powered (80%) to detect changes in radiotracer binding within the caudate.
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Affiliation(s)
- Fernando Caravaggio
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Natasha Porco
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Julia Kim
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Edgardo Torres-Carmona
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Eric Brown
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Yusuke Iwata
- Department of Neuropsychiatry, University of Yamanashi, Chuo, Japan
| | | | - Philip Gerretsen
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Gary Remington
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Ariel Graff-Guerrero
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada
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Bini J, Sanchez-Rangel E, Gallezot JD, Naganawa M, Nabulsi N, Lim K, Najafzadeh S, Shirali A, Ropchan J, Matuskey D, Huang Y, Herold KC, Harris PE, Sherwin RS, Carson RE, Cline GW. PET Imaging of Pancreatic Dopamine D 2 and D 3 Receptor Density with 11C-(+)- PHNO in Type 1 Diabetes. J Nucl Med 2019; 61:570-576. [PMID: 31601695 DOI: 10.2967/jnumed.119.234013] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Type 1 diabetes mellitus (T1DM) has traditionally been characterized by a complete destruction of β-cell mass (BCM); however, there is growing evidence of possible residual BCM present in T1DM. Given the absence of in vivo tools to measure BCM, routine clinical measures of β-cell function (e.g., C-peptide release) may not reflect BCM. We previously demonstrated the potential utility of PET imaging with the dopamine D2 and D3 receptor agonist 3,4,4a,5,6,10b-hexahydro-2H-naphtho[1,2-b][1,4]oxazin-9-ol (11C-(+)-PHNO) to differentiate between healthy control (HC) and T1DM individuals. Methods: Sixteen individuals participated (10 men, 6 women; 9 HCs, 7 T1DMs). The average duration of diabetes was 18 ± 6 y (range, 14-30 y). Individuals underwent PET/CT scanning with a 120-min dynamic PET scan centered on the pancreas. One- and 2-tissue-compartment models were used to estimate pancreas and spleen distribution volume. Reference region approaches (spleen as reference) were also investigated. Quantitative PET measures were correlated with clinical outcome measures. Immunohistochemistry was performed to examine colocalization of dopamine receptors with endocrine hormones in HC and T1DM pancreatic tissue. Results: C-peptide release was not detectable in any T1DM individuals, whereas proinsulin was detectable in 3 of 5 T1DM individuals. Pancreas SUV ratio minus 1 (SUVR-1) (20-30 min; spleen as reference region) demonstrated a statistically significant reduction (-36.2%) in radioligand binding (HCs, 5.6; T1DMs, 3.6; P = 0.03). Age at diagnosis correlated significantly with pancreas SUVR-1 (20-30 min) (R 2 = 0.67, P = 0.025). Duration of diabetes did not significantly correlate with pancreas SUVR-1 (20-30 min) (R 2 = 0.36, P = 0.16). Mean acute C-peptide response to arginine at maximal glycemic potentiation did not significantly correlate with SUVR-1 (20-30 min) (R 2 = 0.57, P = 0.05), nor did mean baseline proinsulin (R 2 = 0.45, P = 0.10). Immunohistochemistry demonstrated colocalization of dopamine D3 receptor and dopamine D2 receptor in HCs. No colocalization of the dopamine D3 receptor or dopamine D2 receptor was seen with somatostatin, glucagon, or polypeptide Y. In a separate T1DM individual, no immunostaining was seen with dopamine D3 receptor, dopamine D2 receptor, or insulin antibodies, suggesting that loss of endocrine dopamine D3 receptor and dopamine D2 receptor expression accompanies loss of β-cell functional insulin secretory capacity. Conclusion: Thirty-minute scan durations and SUVR-1 provide quantitative outcome measures for 11C-(+)-PHNO, a dopamine D3 receptor-preferring agonist PET radioligand, to differentiate BCM in T1DM and HCs.
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Affiliation(s)
- Jason Bini
- PET Center, Yale University School of Medicine, New Haven, Connecticut
| | - Elizabeth Sanchez-Rangel
- Department of Internal Medicine, Division of Endocrinology, Yale University School of Medicine, New Haven, Connecticut; and
| | | | - Mika Naganawa
- PET Center, Yale University School of Medicine, New Haven, Connecticut
| | - Nabeel Nabulsi
- PET Center, Yale University School of Medicine, New Haven, Connecticut
| | - Keunpoong Lim
- PET Center, Yale University School of Medicine, New Haven, Connecticut
| | | | - Anupama Shirali
- PET Center, Yale University School of Medicine, New Haven, Connecticut
| | - Jim Ropchan
- PET Center, Yale University School of Medicine, New Haven, Connecticut
| | - David Matuskey
- PET Center, Yale University School of Medicine, New Haven, Connecticut
| | - Yiyun Huang
- PET Center, Yale University School of Medicine, New Haven, Connecticut
| | - Kevan C Herold
- Department of Internal Medicine, Division of Endocrinology, Yale University School of Medicine, New Haven, Connecticut; and
| | - Paul E Harris
- Department of Medicine, Division of Endocrinology, Columbia University, New York, New York
| | - Robert S Sherwin
- Department of Internal Medicine, Division of Endocrinology, Yale University School of Medicine, New Haven, Connecticut; and
| | - Richard E Carson
- PET Center, Yale University School of Medicine, New Haven, Connecticut
| | - Gary W Cline
- Department of Internal Medicine, Division of Endocrinology, Yale University School of Medicine, New Haven, Connecticut; and
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Caravaggio F, Worhunsky P, Graff-Guerrero A, Matuskey D. Further in vivo characterization of [ 11 C]-(+)- PHNO uptake into a retina-like region of interest in humans. Synapse 2019; 74:e22135. [PMID: 31553807 DOI: 10.1002/syn.22135] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 09/20/2019] [Indexed: 11/12/2022]
Abstract
The neurotransmitter dopamine is present in the retina and is involved in several modulatory functions. Unlike in rodents, dopamine D3 receptors are expressed in the retina of humans. Recently, uptake of the D3 receptor-preferring radiotracer [11 C]-(+)-PHNO has been observed in a retina-like region of interest (ROI) in humans. Here, we attempted to quantify [11 C]-(+)-PHNO uptake into this ROI using an independent sample, employing an extended scan acquisition time (120 min) and arterial kinetic modeling. Data from 14 healthy controls were analyzed (Mean Age: 38.41 ± 9.55, 3 female), 8 of which provided arterial line input function data (Mean Age: 41.07 ± 7.82, 3 female). Using Ichise's multilinear analysis (MA1) method, it was possible to quantify the volume of distribution (VT ) of [11 C]-(+)-PHNO in this retina-like region (Mean VT = 13.56 ± 3.52; Mean χ2 = 2.08 ± 2.20). Notably, the shape of the time activity curve resembled closely that of the globus pallidus. Moreover, the VT values in the retina correlated well with binding potential (BPND ) values calculated using the simplified reference tissue model (Mean BPND = 2.11 ± .94; Mean χ2 = 5.76 ± 2.56), employing the cerebellum as the reference region (r = .76, r2 = .58). In summary, we provide evidence that the in vivo uptake of [11 C]-(+)-PHNO into a retina-like ROI in humans can be quantified using both arterial blood sampling (VT ) and simplified reference tissue methods (BPND ).
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Affiliation(s)
- Fernando Caravaggio
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Patrick Worhunsky
- Department of Psychiatry, Yale University, New Haven, Connecticut, USA
| | - Ariel Graff-Guerrero
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - David Matuskey
- Department of Psychiatry, Yale University, New Haven, Connecticut, USA.,PET Center, Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut, USA.,Department of Neurology, Yale University, New Haven, Connecticut, USA
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Dahoun T, Nour MM, Adams RA, Trossbach S, Lee SH, Patel H, Curtis C, Korth C, Howes OD. Disrupted-in-schizophrenia 1 functional polymorphisms and D 2 /D 3 receptor availability: A [ 11 C]-(+)- PHNO imaging study. Genes Brain Behav 2019; 18:e12596. [PMID: 31264367 DOI: 10.1111/gbb.12596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 06/17/2019] [Accepted: 06/17/2019] [Indexed: 11/28/2022]
Abstract
The disrupted-in-schizophrenia 1 (DISC1) protein has been implicated in a range of biological mechanisms underlying chronic mental disorders such as schizophrenia. Schizophrenia is associated with abnormal striatal dopamine signalling, and all antipsychotic drugs block striatal dopamine 2/3 receptors (D2/3 Rs). Importantly, the DISC1 protein directly interacts and forms a protein complex with the dopamine D2 receptor (D2 R) that inhibits agonist-induced D2 R internalisation. Moreover, animal studies have found large striatal increases in the proportion of D2 R receptors in a high affinity state (D2 high R) in DISC1 rodent models. Here, we investigated the relationship between the three most common polymorphisms altering the amino-acid sequence of the DISC1 protein (Ser704Cys (rs821616), Leu607Phe (rs6675281) and Arg264Gln (rs3738401)) and striatal D2/3 R availability in 41 healthy human volunteers, using [11 C]-(+)-PHNO positron emission tomography. We found no association between DISC1 polymorphisms and D2/3 R availability in the striatum and D2 R availability in the caudate and putamen. Therefore, despite a direct interaction between DISC1 and the D2 R, none of its main functional polymorphisms impact striatal D2/3 R binding potential, suggesting DISC1 variants act through other mechanisms.
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Affiliation(s)
- Tarik Dahoun
- Psychiatric Imaging Group, Robert Steiner MRI Unit, MRC London Institute of Medical Sciences, Hammersmith Hospital, London, UK.,Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, UK.,Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
| | - Matthew M Nour
- Psychiatric Imaging Group, Robert Steiner MRI Unit, MRC London Institute of Medical Sciences, Hammersmith Hospital, London, UK.,Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, UK.,Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience (IoPPN), King's College London, London, UK.,Max Planck UCL Centre for Computational Psychiatry and Ageing Research, University College London, Russell Square House, London, UK.,Wellcome Centre for Human Neuroimaging (WCHN), University College London, London, UK
| | - Rick A Adams
- Psychiatric Imaging Group, Robert Steiner MRI Unit, MRC London Institute of Medical Sciences, Hammersmith Hospital, London, UK.,Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, UK.,Division of Psychiatry, University College London, London, UK.,Institute of Cognitive Neuroscience, University College London, London, UK
| | - Svenja Trossbach
- Department Neuropathology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Sang H Lee
- Department of Biostatistics and Health Informatics, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.,NIHR BioResource Centre Maudsley, NIHR Maudsley Biomedical Research Centre (BRC) at South London and Maudsley NHS Foundation Trust (SLaM) & Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, London, UK.,Social Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, London, UK
| | - Hamel Patel
- Department of Biostatistics and Health Informatics, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.,NIHR BioResource Centre Maudsley, NIHR Maudsley Biomedical Research Centre (BRC) at South London and Maudsley NHS Foundation Trust (SLaM) & Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, London, UK.,Social Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, London, UK
| | - Charles Curtis
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, UK.,Department of Biostatistics and Health Informatics, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.,NIHR BioResource Centre Maudsley, NIHR Maudsley Biomedical Research Centre (BRC) at South London and Maudsley NHS Foundation Trust (SLaM) & Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, London, UK
| | - Carsten Korth
- Department Neuropathology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Oliver D Howes
- Psychiatric Imaging Group, Robert Steiner MRI Unit, MRC London Institute of Medical Sciences, Hammersmith Hospital, London, UK.,Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, UK.,Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience (IoPPN), King's College London, London, UK
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Malik S, Jacobs M, Cho SS, Boileau I, Blumberger D, Heilig M, Wilson A, Daskalakis ZJ, Strafella AP, Zangen A, Le Foll B. Deep TMS of the insula using the H-coil modulates dopamine release: a crossover [ 11C] PHNO-PET pilot trial in healthy humans. Brain Imaging Behav 2018; 12:1306-17. [PMID: 29170944 DOI: 10.1007/s11682-017-9800-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Modulating the function of the insular cortex could be a novel therapeutic strategy to treat addiction to a variety of drugs of abuse as this region has been implicated in mediating drug reward and addictive processes. The recent advent of the H-coil has permitted the targeting of deeper brain structures which was not previously feasible. The goal of this study was to bilaterally target the insular region using the H-coil with repetitive Transcranial Magnetic Stimulation (rTMS) and subsequently measure changes in dopamine levels using Positron Emission Tomography (PET) with [11C]-(+)-propyl-hexahydro-naphtho-oxazin (PHNO). This was a within-subject, crossover, blinded and sham-controlled pilot study. Eight healthy, right-handed subjects, aged 19-45, participated in the investigation. All subjects underwent 3 PHNO-PET scans preceded by rTMS (sham, 1 Hz or 10 Hz), on 3 separate days. Low frequency rTMS (1 Hz), targeting the insular cortex, significantly decreased dopamine levels in the substantia nigra, sensorimotor striatum and associative striatum. Replicating this study in tobacco smokers or alcoholics would be a logical follow-up to assess whether H-coil stimulation of the bilateral insula can be employed as a treatment option for addiction. Trial registration: NCT02212405.
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Bini J, Naganawa M, Nabulsi N, Huang Y, Ropchan J, Lim K, Najafzadeh S, Herold KC, Cline GW, Carson RE. Evaluation of PET Brain Radioligands for Imaging Pancreatic β-Cell Mass: Potential Utility of 11C-(+)- PHNO. J Nucl Med 2018; 59:1249-1254. [PMID: 29371405 DOI: 10.2967/jnumed.117.197285] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 12/07/2017] [Indexed: 12/21/2022] Open
Abstract
Type 1 diabetes mellitus (T1DM) is characterized by a loss of β-cells in the islets of Langerhans of the pancreas and subsequent deficient insulin secretion in response to hyperglycemia. Development of an in vivo test to measure β-cell mass (BCM) would greatly enhance the ability to track diabetes therapies. β-cells and neurologic tissues have common cellular receptors and transporters, therefore, we screened brain radioligands for their ability to identify β-cells. Methods: We examined a β-cell gene atlas for endocrine pancreas receptor targets and cross-referenced these targets with brain radioligands that were available at our institution. Twelve healthy control subjects and 2 T1DM subjects underwent dynamic PET/CT scans with 6 tracers. Results: The D2/D3 receptor agonist radioligand 11C-(+)-4-propyl-9-hydroxynaphthoxazine (PHNO) was the only radioligand to demonstrate sustained uptake in the pancreas with high contrast versus abdominal organs such as the kidneys, liver, and spleen, based on the first 30 min of data. Mean SUV from 20 to 30 min demonstrated high uptake of 11C-(+)-PHNO in healthy controls (SUV, 13.8) with a 71% reduction in a T1DM subject with undetectable levels of C-peptide (SUV, 4.0) and a 20% reduction in a T1DM subject with fasting C-peptide level of 0.38 ng/mL (SUV, 11.0). SUV in abdominal organs outside the pancreas did not show measurable differences between the control and T1DM subjects, suggesting that the changes in SUV of 11C-(+)-PHNO may be specific to changes in the pancreas between healthy controls and T1DM subjects. When D3 and D2 antagonists were used in nonhuman primates, specific pancreatic binding (SUVR-1) of 11C-PHNO was reduced by 57% and 38%, respectively. Conclusion:11C-(+)-PHNO is a potential marker of BCM, with 2:1 binding of D3 receptors over D2 receptors. Further in vitro and in vivo studies to establish D2/D3 receptor specificity to β-cells is warranted to characterize 11C-(+)-PHNO as a candidate for clinical measurement of BCM in healthy control and diabetic subjects.
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Affiliation(s)
- Jason Bini
- PET Center, Yale University School of Medicine, New Haven, CT .,Department of Biomedical Engineering, Yale University, New Haven, CT; and
| | - Mika Naganawa
- PET Center, Yale University School of Medicine, New Haven, CT
| | - Nabeel Nabulsi
- PET Center, Yale University School of Medicine, New Haven, CT
| | - Yiyun Huang
- PET Center, Yale University School of Medicine, New Haven, CT
| | - Jim Ropchan
- PET Center, Yale University School of Medicine, New Haven, CT
| | - Keunpoong Lim
- PET Center, Yale University School of Medicine, New Haven, CT
| | | | - Kevan C Herold
- Department of Immunobiology and Internal Medicine, Yale University School of Medicine, New Haven, CT
| | - Gary W Cline
- Department of Immunobiology and Internal Medicine, Yale University School of Medicine, New Haven, CT
| | - Richard E Carson
- PET Center, Yale University School of Medicine, New Haven, CT.,Department of Biomedical Engineering, Yale University, New Haven, CT; and
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Di Ciano P, Cormick PM, Stefan C, Wong E, Kim A, Remington G, Le Foll B. The effects of buspirone on occupancy of dopamine receptors and the rat gambling task. Psychopharmacology (Berl) 2017; 234:3309-3320. [PMID: 28825117 DOI: 10.1007/s00213-017-4715-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 08/04/2017] [Indexed: 11/27/2022]
Abstract
BACKGROUND The dopamine D3 receptor (DRD3) has been proposed as a target for drug development for the treatment of addictive disorders. Recently, the anxiolytic buspirone has been shown to have affinity for DRD3 and DRD4, and interest in repurposing it for addictive disorders has grown. METHODS Binding of [3H]-(+)-PHNO in the rat cerebellum and striatum was used to measure occupancy by buspirone of DRD3 or DRD2, respectively. Effects of buspirone in the rat gambling task (rGT) and the five-choice serial reaction time task (5-CSRTT) were examined. RESULTS Buspirone occupied both the DRD2 and DRD3 at high doses and the DRD3, but not the DRD2, in the narrow dose range of 3 mg/kg. At 10 mg/kg, a disruption of performance on rGT was observed. All measures of performance on the rGT, except for perseverations, were affected at 3 mg/kg. On the 5-CSRTT, omissions were increased. Impairments in the rGT were not mimicked by the effects induced by satiation. Further, buspirone did not impair food-maintained responding under a progressive ratio schedule of reinforcement at any dose, suggesting that the effects of buspirone on the rGT cannot be explained by non-selective actions. CONCLUSIONS Although buspirone had effects on the rGT at the dose that selectively occupied the DRD3, the effects found do not parallel those found in previous studies of the effects of selective DRD3 antagonists on the rGT. Thus, buspirone may impair performance on the rGT through actions at multiple receptor sites.
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Affiliation(s)
- Patricia Di Ciano
- Translational Addiction Research Laboratory, Centre for Addiction and Mental Health (CAMH), University of Toronto, 33 Russell Street, Toronto, M5S 2S1, Canada
| | | | - Cristiana Stefan
- Clinical Laboratory and Diagnostic Services, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Ernest Wong
- Clinical Laboratory and Diagnostic Services, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Aaron Kim
- Translational Addiction Research Laboratory, Centre for Addiction and Mental Health (CAMH), University of Toronto, 33 Russell Street, Toronto, M5S 2S1, Canada
| | - Gary Remington
- Translational Addiction Research Laboratory, Centre for Addiction and Mental Health (CAMH), University of Toronto, 33 Russell Street, Toronto, M5S 2S1, Canada
- Addiction Medicine Service, Acute Care Program, CAMH, Toronto, ON, Canada
- CAMH, Campbell Family Mental Health Research Institute, Toronto, ON, Canada
- Division of Brain and Therapeutics, Department of Psychiatry, University of Toronto, Toronto, ON, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | - Bernard Le Foll
- Translational Addiction Research Laboratory, Centre for Addiction and Mental Health (CAMH), University of Toronto, 33 Russell Street, Toronto, M5S 2S1, Canada.
- Addiction Medicine Service, Acute Care Program, CAMH, Toronto, ON, Canada.
- CAMH, Campbell Family Mental Health Research Institute, Toronto, ON, Canada.
- Department of Family and Community Medicine, University of Toronto, Toronto, ON, Canada.
- Department of Pharmacology, University of Toronto, Toronto, ON, Canada.
- Division of Brain and Therapeutics, Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada.
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Caravaggio F, Ku Chung J, Plitman E, Boileau I, Gerretsen P, Kim J, Iwata Y, Patel R, Chakravarty MM, Remington G, Graff-Guerrero A. The relationship between subcortical brain volume and striatal dopamine D 2/3 receptor availability in healthy humans assessed with [ 11 C]-raclopride and [ 11 C]-(+)- PHNO PET. Hum Brain Mapp 2017; 38:5519-5534. [PMID: 28752565 DOI: 10.1002/hbm.23744] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 06/21/2017] [Accepted: 07/16/2017] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Abnormalities in dopamine (DA) and brain morphology are observed in several neuropsychiatric disorders. However, it is not fully understood how these abnormalities may relate to one another. For such in vivo findings to be used as biomarkers for neuropsychiatric disease, it must be understood how variability in DA relates to brain structure under healthy conditions. We explored how the availability of striatal DA D2/3 receptors (D2/3 R) is related to the volume of subcortical brain structures in a sample of healthy humans. Differences in D2/3 R availability measured with an antagonist radiotracer ([11 C]-raclopride) versus an agonist radiotracer ([11 C]-(+)-PHNO) were examined. METHODS Data from 62 subjects scanned with [11 C]-raclopride (mean age = 38.98 ± 14.45; 23 female) and 68 subjects scanned with [11 C]-(+)-PHNO (mean age = 38.54 ± 14.59; 25 female) were used. Subcortical volumes were extracted from T1-weighted images using the Multiple Automatically Generated Templates (MAGeT-Brain) algorithm. Partial correlations were used controlling for age, gender, and total brain volume. RESULTS For [11 C]-(+)-PHNO, ventral caudate volumes were positively correlated with BPND in the dorsal caudate and globus pallidus (GP). Ventral striatum (VS) volumes were positively correlated with BPND in the VS. With [11 C]-raclopride, BPND in the VS was negatively correlated with subiculum volume of the hippocampus. Moreover, BPND in the GP was negatively correlated with the volume of the lateral posterior nucleus of the thalamus. CONCLUSION Findings are purely exploratory and presented corrected and uncorrected for multiple comparisons. We hope they will help inform the interpretation of future PET studies where concurrent changes in D2/3 R and brain morphology are observed. Hum Brain Mapp 38:5519-5534, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Fernando Caravaggio
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario, M5T 1R8, Canada.,Department of Psychiatry, University of Toronto, 250 College Street, Toronto, Ontario, M5T 1R8, Canada
| | - Jun Ku Chung
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario, M5T 1R8, Canada
| | - Eric Plitman
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario, M5T 1R8, Canada
| | - Isabelle Boileau
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario, M5T 1R8, Canada.,Department of Psychiatry, University of Toronto, 250 College Street, Toronto, Ontario, M5T 1R8, Canada
| | - Philip Gerretsen
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario, M5T 1R8, Canada.,Department of Psychiatry, University of Toronto, 250 College Street, Toronto, Ontario, M5T 1R8, Canada
| | - Julia Kim
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario, M5T 1R8, Canada
| | - Yusuke Iwata
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario, M5T 1R8, Canada.,Department of Psychiatry, University of Toronto, 250 College Street, Toronto, Ontario, M5T 1R8, Canada
| | - Raihaan Patel
- Department of Biological & Biomedical Engineering, McGill University, Montreal, Quebec, H4H 1R3, Canada.,Cerebral Imaging Centre, Douglas Mental Health Institute, McGill University, Montreal, Quebec, H4H 1R3, Canada
| | - M Mallar Chakravarty
- Department of Biological & Biomedical Engineering, McGill University, Montreal, Quebec, H4H 1R3, Canada.,Cerebral Imaging Centre, Douglas Mental Health Institute, McGill University, Montreal, Quebec, H4H 1R3, Canada.,Department of Psychiatry, McGill University, Montreal, Quebec, H4H 1R3, Canada
| | - Gary Remington
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario, M5T 1R8, Canada.,Department of Psychiatry, University of Toronto, 250 College Street, Toronto, Ontario, M5T 1R8, Canada
| | - Ariel Graff-Guerrero
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario, M5T 1R8, Canada.,Department of Psychiatry, University of Toronto, 250 College Street, Toronto, Ontario, M5T 1R8, Canada
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Weidenauer A, Bauer M, Sauerzopf U, Bartova L, Praschak-Rieder N, Sitte HH, Kasper S, Willeit M. Making Sense of: Sensitization in Schizophrenia. Int J Neuropsychopharmacol 2016; 20:1-10. [PMID: 27613293 PMCID: PMC5604613 DOI: 10.1093/ijnp/pyw081] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 09/07/2016] [Indexed: 12/12/2022] Open
Abstract
Sensitization is defined as a process whereby repeated intermittent exposure to a given stimulus results in an enhanced response at subsequent exposures. Next to robust findings of an increased dopamine synthesis capacity in schizophrenia, empirical data and neuroimaging studies support the notion that the mesolimbic dopamine system of patients with schizophrenia is more reactive compared with healthy controls. These studies led to the conceptualization of schizophrenia as a state of endogenous sensitization, as stronger behavioral response and increased dopamine release after amphetamine administration or exposure to stress have been observed in patients with schizophrenia. These findings have also been integrated into the neurodevelopmental model of the disorder, which assumes that vulnerable neuronal circuits undergo progressive changes during puberty and young adulthood that lead to manifest psychosis. Rodent and human studies have made an attempt to identify the exact mechanisms of sensitization of the dopaminergic system and its association with psychosis. Doing so, several epigenetic and molecular alterations associated with dopamine release, neuroplasticity, and cellular energy metabolism have been discovered. Future research aims at targeting these key proteins associated with sensitization in schizophrenia to enhance the knowledge of the pathophysiology of the illness and pave the way for an improved treatment or even prevention of this severe psychiatric disorder.
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Affiliation(s)
- Ana Weidenauer
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria (Drs Weidenauer, Bauer, Sauerzopf, Bartova, Praschak-Rieder, Kasper, and Willeit); Department of Clinical Pharmacology (Dr Bauer), and Institute of Pharmacology, Medical University of Vienna, Austria (Dr Sitte)
| | - Martin Bauer
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria (Drs Weidenauer, Bauer, Sauerzopf, Bartova, Praschak-Rieder, Kasper, and Willeit); Department of Clinical Pharmacology (Dr Bauer), and Institute of Pharmacology, Medical University of Vienna, Austria (Dr Sitte)
| | - Ulrich Sauerzopf
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria (Drs Weidenauer, Bauer, Sauerzopf, Bartova, Praschak-Rieder, Kasper, and Willeit); Department of Clinical Pharmacology (Dr Bauer), and Institute of Pharmacology, Medical University of Vienna, Austria (Dr Sitte)
| | - Lucie Bartova
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria (Drs Weidenauer, Bauer, Sauerzopf, Bartova, Praschak-Rieder, Kasper, and Willeit); Department of Clinical Pharmacology (Dr Bauer), and Institute of Pharmacology, Medical University of Vienna, Austria (Dr Sitte)
| | - Nicole Praschak-Rieder
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria (Drs Weidenauer, Bauer, Sauerzopf, Bartova, Praschak-Rieder, Kasper, and Willeit); Department of Clinical Pharmacology (Dr Bauer), and Institute of Pharmacology, Medical University of Vienna, Austria (Dr Sitte)
| | - Harald H. Sitte
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria (Drs Weidenauer, Bauer, Sauerzopf, Bartova, Praschak-Rieder, Kasper, and Willeit); Department of Clinical Pharmacology (Dr Bauer), and Institute of Pharmacology, Medical University of Vienna, Austria (Dr Sitte)
| | - Siegfried Kasper
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria (Drs Weidenauer, Bauer, Sauerzopf, Bartova, Praschak-Rieder, Kasper, and Willeit); Department of Clinical Pharmacology (Dr Bauer), and Institute of Pharmacology, Medical University of Vienna, Austria (Dr Sitte).
| | - Matthäus Willeit
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria (Drs Weidenauer, Bauer, Sauerzopf, Bartova, Praschak-Rieder, Kasper, and Willeit); Department of Clinical Pharmacology (Dr Bauer), and Institute of Pharmacology, Medical University of Vienna, Austria (Dr Sitte)
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Girgis RR, Xu X, Gil RB, Hackett E, Ojeil N, Lieberman JA, Slifstein M, Abi-Dargham A. Antipsychotic binding to the dopamine-3 receptor in humans: A PET study with [(11)C]-(+)- PHNO. Schizophr Res 2015; 168:373-6. [PMID: 26190300 PMCID: PMC4591174 DOI: 10.1016/j.schres.2015.06.027] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 06/25/2015] [Accepted: 06/29/2015] [Indexed: 11/29/2022]
Abstract
BACKGROUND All currently available antipsychotic medications bind to both the dopamine-2 (D2) and dopamine-3 (D3) receptors in vitro. However, there is conflicting evidence from in vivo studies about whether or not antipsychotic medications bind to the D3 receptor (D3R). The purpose of this study was to determine whether acute doses of risperidone bind to the D3R in humans. METHODS We performed PET scans on an mCT scanner with [(11)C]-(+)-PHNO injected as a bolus, before and after a 2mg oral dose of risperidone in five medication free subjects with schizophrenia. The subjects were scanned for 120min and underwent an MRI scan for region of interest delineation and coregistration. Cerebellum was used as a reference region. Simplified reference tissue modeling (SRTM) was used to calculate BPND. RESULTS We observed binding to the D3R receptor by risperidone as evidenced by observable occupancy in regions in which the [(11)C]-(+)-PHNO signal is almost exclusively from the D3R (i.e., substantia nigra/ventral tegmental area). Using a regression model to estimate D2R:D3R selectivity, we observed a D2R:D3R selectivity of 2.1 for risperidone. CONCLUSION Our preliminary results provide further support that acute doses of antipsychotic medications bind to the D3R and provide additional support for the further development of this receptor as a treatment target in schizophrenia.
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Affiliation(s)
- Ragy R. Girgis
- Corresponding author, Tel. +1 646 774 5553; fax: +1 212 568 6171.
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Maggio R, Scarselli M, Capannolo M, Millan MJ. Novel dimensions of D3 receptor function: Focus on heterodimerisation, transactivation and allosteric modulation. Eur Neuropsychopharmacol 2015; 25:1470-9. [PMID: 25453482 DOI: 10.1016/j.euroneuro.2014.09.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 09/24/2014] [Indexed: 02/08/2023]
Abstract
The brain׳s complexity derives not only from the way the intricate network of neurons is wired, but also by protein complexes that recognize and decode chemical information. G protein-coupled receptors (GPCRs) represent the most abundant family of proteins mediating neurotransmission in the brain, and their ability to form homo- and heteromers which amplifies the scope for synaptic communication and fine-tuning. Dopamine receptors are important drug targets and members of both the D1/D5 and D2/D3/D4 receptor families form homo- and heteromers. The present article focuses on D3 receptor homo- and heteromers, in particular, those formed in association with their D2 counterparts. We highlight the binding profiles and mechanisms of interaction with D3-D3 homomers and D3-D2 heteromers of: first, the PET ligand and potent agonist [(11)C]-(+)-PHNO; second, the novel, bitopic/allosteric dopamine D3 receptor antagonist, SB269,652; and third, diverse partial agonists like antipsychotic and aripiprazole. Molecular mechanisms of interplay between the two protomers of heteromeric D3-D2 complexes are likewise discussed: for example, "transactivation", whereby recruitment of one member of a heteromer harnesses signalling pathways is normally coupled to the other protomer. Finally, D1 receptor heteromers are also taken into consideration in deciphering the nature of interfaces required to stabilize dimeric assemblies and permit their interaction with G proteins. Improved understanding of D3 as well as D2 and D1 receptor complexes should yield important insights into their physiological roles and pathological significance, and permit the development of novel drug classes with potentially distinctive functional profiles and improved therapeutic windows.
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