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Weinstein AM. A brain imaging study of dopamine receptor D 2 availability in cannabis dependent users after recovery from cannabis-induced psychosis. Front Psychiatry 2023; 14:1230760. [PMID: 37965367 PMCID: PMC10641483 DOI: 10.3389/fpsyt.2023.1230760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 10/11/2023] [Indexed: 11/16/2023] Open
Abstract
There is increased risk of psychosis associated with cannabis use disorder and the interaction of THC with dopamine neurotransmission is complex. It is important to investigate the recovery from cannabis-induced psychosis and its effects on the brain's dopamine neurotransmission. This study was to evaluate dopamine receptor D2 availability in the striatum (caudate/putamen) in recently abstinent cannabis dependent users after recovery from psychosis in comparison with abstinent MDMA "ecstasy" abusers and healthy control participants. Participants were eight abstinent ex cannabis-dependent users who were treated for cannabis-induced psychosis with anti-psychotic medication and psychosocial support for 4 months in an inpatient treatment center for drug users. They were compared with nine abstinent ex MDMA "ecstasy" abusers who received medication and psycho-social treatment for 4 months at the same treatment facility and eight healthy control participants. All participants were scanned with bolus and constant infusion of [123I] Iodobenzamide (IBZM) in Single Photon Computed Tomography (SPECT). Cannabis abstinent users who were treated for cannabis-induced psychotic episodes showed no difference in dopamine D2 receptor availability in the caudate compared with abstinent MDMA "ecstasy" abusers and healthy control participants. This finding indicates minimal effects of cannabis-induced psychosis on dopamine reward mechanisms. There is evidence for reduced D2 receptor availability measures in the right putamen (uncorrected) which may indicate a residual effect of anti-psychotic medication.
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Affiliation(s)
- Aviv M. Weinstein
- Department of Psychology and Behavioral Science, Ariel University, Ariel, Israel
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Moustapha ME, Geesi MH, Farag ZR, Anouar EH. Electrophilic Aromatic Synthesis of Radioiodinated Aripiprazole: Experimental and DFT Investigations. Curr Org Synth 2020; 17:295-303. [PMID: 32271696 DOI: 10.2174/1570179417666200409145824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 02/06/2020] [Accepted: 02/07/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Aripiprazole is a quinolinone derivative. It shows a high affinity for neurotransmitters dopamine and serotonin receptors, which can overcome the blood-brain barrier (BBB) to reach the central nervous system (CNS) to exert therapeutic effects. Its radioiodination may lead to high radiochemical yield and improved its affinity. Aripiprazole radioiodination is an aromatic electrophilic substitution. OBJECTIVE Herein, we investigate the favorable atom site of the aromatic electrophilic substitution of aripiprazole by calculating the Fukui indices of heavy atoms and ESP charges of the parent molecule. METHODS The calculations have been carried out at the B3LYP/LanL2DZ level of theory. The iodinated aripiprazole structure is confirmed by comparing the experimental and the predicted 1H NMR chemical shifts of the parent molecule and its iodinated forms. RESULTS Finally, the electronic properties of aripiprazole and its iodinated form were calculated at the same level of theory. Nucleophilic Fukui indices and ESP charges calculations confirm that C8 is the most favorable site of the electrophilic substitution. The calculated electronic properties (e.g, gap energy, electron affinity, and electronegativity) of aripiprazole and its iodinated form reveal the higher reactivity of iodinated aripiprazole compared with aripiprazole. CONCLUSION This may explain the higher affinity of iodinated aripiprazole and the increase of its radiochemical yield.
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Affiliation(s)
- Moustapha E Moustapha
- Department of Chemistry, College of Science and Humanities in Al-Kharj, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia
| | - Mohammed H Geesi
- Department of Chemistry, College of Science and Humanities in Al-Kharj, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia
| | - Zeinab R Farag
- Chemistry Department, Faculty of Science, Fayoum University, Fayoum, Egypt
| | - El Hassane Anouar
- Department of Chemistry, College of Science and Humanities in Al-Kharj, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia
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Nikolaus S, Mamlins E, Hautzel H, Müller HW. Acute anxiety disorder, major depressive disorder, bipolar disorder and schizophrenia are related to different patterns of nigrostriatal and mesolimbic dopamine dysfunction. Rev Neurosci 2019; 30:381-426. [PMID: 30269107 DOI: 10.1515/revneuro-2018-0037] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 06/30/2018] [Indexed: 11/15/2022]
Abstract
Dopamine (DA) receptor and transporter dysfunctions play a major role in the pathophysiology of neuropsychiatric diseases including anxiety disorder (AD), major depressive disorder (MDD), bipolar disorder (BD) in the manic (BDman) or depressive (BDdep) state and schizophrenia (SZ). We performed a PUBMED search, which provided a total of 239 in vivo imaging studies with either positron emission tomography (PET) or single-proton emission computed tomography (SPECT). In these studies, DA transporter binding, D1 receptor (R) binding, D2R binding, DA synthesis and/or DA release in patients with the primary diagnosis of acute AD (n=310), MDD (n=754), BDman (n=15), BDdep (n=49) or SZ (n=1532) were compared to healthy individuals. A retrospective analysis revealed that AD, MDD, BDman, BDdep and SZ differed as to affected brain region(s), affected synaptic constituent(s) and extent as well as direction of dysfunction in terms of either sensitization or desensitization of transporter and/or receptor binding sites. In contrast to AD and SZ, in MDD, BDman and BDdep, neostriatal DA function was normal, whereas MDD, BDman, and BDdep were characterized by the increased availability of prefrontal and frontal DA. In contrast to AD, MDD, BDman and BDdep, DA function in SZ was impaired throughout the nigrostriatal and mesolimbocortical system with an increased availability of DA in the striatothalamocortical and a decreased availability in the mesolimbocortical pathway.
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Affiliation(s)
- Susanne Nikolaus
- Clinic of Nuclear Medicine, University Hospital Düsseldorf, Heinrich Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Eduards Mamlins
- Clinic of Nuclear Medicine, University Hospital Düsseldorf, Heinrich Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Hubertus Hautzel
- Clinic of Nuclear Medicine, University Hospital Düsseldorf, Heinrich Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Hans-Wilhelm Müller
- Clinic of Nuclear Medicine, University Hospital Düsseldorf, Heinrich Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
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Lopes Alves I, Willemsen AT, Dierckx RA, da Silva AMM, Koole M. Dual time-point imaging for post-dose binding potential estimation applied to a [ 11C]raclopride PET dose occupancy study. J Cereb Blood Flow Metab 2017; 37:866-876. [PMID: 27073203 PMCID: PMC5363466 DOI: 10.1177/0271678x16644463] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Receptor occupancy studies performed with PET often require time-consuming dynamic imaging for baseline and post-dose scans. Shorter protocol approximations based on standard uptake value ratios have been proposed. However, such methods depend on the time-point chosen for the quantification and often lead to overestimation and bias. The aim of this study was to develop a shorter protocol for the quantification of post-dose scans using a dual time-point approximation, which employs kinetic parameters from the baseline scan. Dual time-point was evaluated for a [11C]raclopride PET dose occupancy study with the D2 antagonist JNJ-37822681, obtaining estimates for binding potential and receptor occupancy. Results were compared to standard simplified reference tissue model and standard uptake value ratios-based estimates. Linear regression and Bland-Altman analysis demonstrated excellent correlation and agreement between dual time-point and the standard simplified reference tissue model approach. Moreover, the stability of dual time-point-based estimates is shown to be independent of the time-point chosen for quantification. Therefore, a dual time-point imaging protocol can be applied to post-dose [11C]raclopride PET scans, resulting in a significant reduction in total acquisition time while maintaining accuracy in the quantification of both the binding potential and the receptor occupancy.
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Affiliation(s)
- Isadora Lopes Alves
- 1 Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Antoon Tm Willemsen
- 1 Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Rudi A Dierckx
- 1 Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Ana Maria M da Silva
- 2 Laboratory of Medical Imaging, School of Physics, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Michel Koole
- 1 Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,3 Department of Nuclear Medicine and Molecular Imaging, KU Leuven, Leuven, Belgium
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Nakajima S, Uchida H, Bies RR, Caravaggio F, Suzuki T, Plitman E, Mar W, Gerretsen P, Pollock BG, Mulsant BH, Mamo DC, Graff-Guerrero A. Dopamine D2/3 Receptor Occupancy Following Dose Reduction Is Predictable With Minimal Plasma Antipsychotic Concentrations: An Open-Label Clinical Trial. Schizophr Bull 2016. [PMID: 26221049 PMCID: PMC4681559 DOI: 10.1093/schbul/sbv106] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Population pharmacokinetics can predict antipsychotic blood concentrations at a given time point prior to a dosage change. Those predicted blood concentrations could be used to estimate the corresponding dopamine D2/3 receptors (D2/3R) occupancy by antipsychotics based on the tight relationship between blood and brain pharmacokinetics. However, this 2-step prediction has never been tested. METHODS Two blood samples were collected at separate time points from 32 clinically stable outpatients with schizophrenia (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition; mean ± SD age: 60.1 ± 7.3 years) to measure plasma concentrations of olanzapine or risperidone at baseline. Then, subjects underwent a dose reduction of olanzapine or risperidone and completed a [(11)C]-raclopride positron emission tomography scan to measure D2/3R occupancy in the putamen. The plasma concentration at the time of the scan was predicted with the 2 samples based on population pharmacokinetic model, using NONMEM. D2/3R occupancy was then estimated by incorporating the predicted plasma concentration in a hyperbole saturation model. The predicted occupancy was compared to the observed value. RESULTS The mean (95% CI) prediction errors for the prediction of D2/3R occupancy were -1.76% (-5.11 to 1.58) for olanzapine and 0.64% (-6.18 to 7.46) for risperidone. The observed and predicted D2/3R occupancy levels were highly correlated (r = 0.67, P = .001 for olanzapine; r = 0.67, P = .02 for risperidone). CONCLUSIONS D2/3R occupancy levels can be predicted from blood drug concentrations collected prior to dosage change. Although this 2-step model is subject to a small degree of error, it could be used to select oral doses aimed at achieving optimal D2/3R occupancy on an individual basis.
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Affiliation(s)
| | - Hiroyuki Uchida
- Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, Canada; Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan;
| | - Robert R. Bies
- Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, Canada;,Indiana University School of Medicine, Division of Clinical Pharmacology, Indianapolis, IN
| | - Fernando Caravaggio
- Multimodal Imaging Group - Research Imaging Centre and,Department of Psychiatry, University of Toronto, Toronto, Canada;,Institute of Medical Science, University of Toronto, Toronto, Canada
| | - Takefumi Suzuki
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Eric Plitman
- Multimodal Imaging Group - Research Imaging Centre and,Department of Psychiatry, University of Toronto, Toronto, Canada;,Institute of Medical Science, University of Toronto, Toronto, Canada
| | - Wanna Mar
- Multimodal Imaging Group - Research Imaging Centre and
| | - Philip Gerretsen
- Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Bruce G. Pollock
- Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, Canada;,Department of Psychiatry, University of Toronto, Toronto, Canada;,Campbell Research Institute, Centre for Addiction and Mental Health, Toronto, Canada
| | - Benoit H. Mulsant
- Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, Canada;,Department of Psychiatry, University of Toronto, Toronto, Canada;,Campbell Research Institute, Centre for Addiction and Mental Health, Toronto, Canada
| | - David C. Mamo
- Department of Psychiatry, University of Toronto, Toronto, Canada
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Vyas NS, Patel NH, Nijran KS, Al-Nahhas A, Puri BK. The use of PET imaging in studying cognition, genetics and pharmacotherapeutic interventions in schizophrenia. Expert Rev Neurother 2014; 11:37-51. [DOI: 10.1586/ern.10.160] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Gómez-Vallejo V, Vázquez N, Gona KB, Puigivila M, González M, Sebastián ES, Martin A, Llop J. Synthesis andin vivoevaluation of11C-labeled (1,7-dicarba-closo-dodecaboran-1-yl)-N-{[(2S)-1-ethylpyrrolidin-2-yl]methyl}amide. J Labelled Comp Radiopharm 2013; 57:209-14. [DOI: 10.1002/jlcr.3159] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 10/29/2013] [Indexed: 01/02/2023]
Affiliation(s)
- Vanessa Gómez-Vallejo
- Radiochemistry Department, Molecular Imaging Unit; CIC biomaGUNE; Parque Tecnológico de Miramón; San Sebastián Guipúzcoa Spain
| | - Naiara Vázquez
- Radiochemistry Department, Molecular Imaging Unit; CIC biomaGUNE; Parque Tecnológico de Miramón; San Sebastián Guipúzcoa Spain
| | - Kiran Babu Gona
- Radiochemistry Department, Molecular Imaging Unit; CIC biomaGUNE; Parque Tecnológico de Miramón; San Sebastián Guipúzcoa Spain
| | - Maria Puigivila
- Radiochemistry Department, Molecular Imaging Unit; CIC biomaGUNE; Parque Tecnológico de Miramón; San Sebastián Guipúzcoa Spain
| | - Mikel González
- Radiochemistry Department, Molecular Imaging Unit; CIC biomaGUNE; Parque Tecnológico de Miramón; San Sebastián Guipúzcoa Spain
| | - Eneko San Sebastián
- Image Analytics Department, Molecular Imaging Unit; CIC biomaGUNE; Parque Tecnológico de Miramón; San Sebastián Guipúzcoa Spain
| | - Abraham Martin
- Molecular Imaging Unit; CIC biomaGUNE; Parque Tecnológico de Miramón; San Sebastián Guipúzcoa Spain
| | - Jordi Llop
- Radiochemistry Department, Molecular Imaging Unit; CIC biomaGUNE; Parque Tecnológico de Miramón; San Sebastián Guipúzcoa Spain
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Abstract
RATIONALE Dose equivalents based on dopamine D₂ receptor occupancy can be used to compare antipsychotics on D₂ receptor-mediated (adverse) effects such as extrapyramidal symptoms and altered emotional experiences. Previous meta-analyses modeling the dose-occupancy relationship hardly addressed potential heterogeneity of the imaging data. OBJECTIVES To model the relationship between dose and D₂ receptor occupancy for a series of frequently prescribed antipsychotics while addressing the potential heterogeneity of the imaging data. METHODS We conducted a meta-analysis on published D₂ receptor occupancy data (positron emission tomography and single-photon emission computed tomography) in patients with schizophrenia treated with antipsychotics. A nonlinear mixed effects model estimated the median D₂ receptor occupancy for a given antipsychotic dose. Heterogeneity between studies was investigated by incorporating study as a random effect in the model, in addition to patient- and study-specific explanatory variables. RESULTS Included were 51 studies, describing 606 patients (mean ± SD age, 32.2 ±10.8 years; 25.7% female). The models described the dose-occupancy relationship with narrow confidence bands around the therapeutic dose range. Maximum occupancy (95% confidence interval[CI]) was estimated for haloperidol (91.9%; 95% CI, 86.1-97.8), risperidone(92.4%; 95% CI, 81.8-100), olanzapine (96.5%; 95% CI,85.8-100), clozapine (61.7%; 95% CI, 49.2-74.2), quetiapine (49.1%; 95% CI, 18.7-79.6), aripiprazole (86.9%; 95% CI, 78.2-95.7), ziprasidone (82.9%; 95% CI, 44.9-100), and amisulpride (85.0%; 95% CI, 68.5-100). Interindividual differences explained most of the variability in occupancy values, besides significant heterogeneity between studies. CONCLUSIONS Dose-occupancy functions estimated the median level of dopamine D₂ receptor occupancy for 8 frequently prescribed antipsychotics in patients with schizophrenia. These dose equivalents can be used to compare antipsychotic effects in epidemiological studies and clinical practice.
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Mo SJ, Larsson A, Johansson L, Stenlund H, Forsgren L, Riklund K. Cross-camera comparison of ROI-based semi-quantitative ¹²³I-IBZM SPECT data in healthy volunteers using an anthropomorphic phantom for calibration. Acta Radiol 2013; 54:549-56. [PMID: 23463862 DOI: 10.1177/0284185113477392] [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: 11/16/2022]
Abstract
BACKGROUND In (123)I-Iolopride (IBZM) SPECT reference values may diverge between camera systems. If multicenter pooling of normal material databases is needed, differences in measured semi-quantitative data due to equipment performance and reconstruction parameters have to be investigated in each instance to determine the comparability. PURPOSE To explore the differences in (123)I-IBZM measured uptake ratios between two different gamma cameras in healthy controls, the intra-rater reproducibility of the image evaluation method and the possibility to equalize uptake ratios by calibration through an anthropomorphic phantom. MATERIAL AND METHODS Differences in ROI-based semi-quantitative data from two different gamma camera systems, the three-headed brain dedicated Neurocam and the two-headed multipurpose hybrid system Infinia Hawkeye, were studied using image data from a group of healthy volunteers and an anthropomorphic brain-phantom scanned with both cameras. Several reconstruction methods and corrections were applied. To test the reliability of the ROI method, the intra-observer reproducibility was determined for the ROI method in this study. RESULTS The ROI method had a high reliability. Differences in mean measured uptake (123)I-IBZM ratios in healthy controls varied between 2.9% and 6.5% depending on reconstruction and correction for attenuation and scatter. After calibration, the differences decreased. There were no statistically significant differences between corrected ratios from the two camera systems in the study when images were reconstructed with attenuation correction. CONCLUSION The conformity of uptake ratios in attenuation corrected (123)I-IBZM images derived from the two different cameras was improved by using an anthropomorphic phantom for calibration.
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Affiliation(s)
- Susanna Jakobson Mo
- Department of Radiation Sciences, Diagnostic Radiology, Umeå University, Umeå
| | - Anne Larsson
- Department of Radiation Sciences, Radiation Physics, Umeå University, Umeå
| | - Lennart Johansson
- Department of Radiation Sciences, Radiation Physics, Umeå University, Umeå
| | - Hans Stenlund
- Department of Public Health and Clinical Medicine, Epidemiology and Global Health, Umeå University, Umeå, Sweden
| | - Lars Forsgren
- Department of Pharmacology and Clinical Neuroscience, Neurology, Umeå University, Umeå
| | - Katrine Riklund
- Department of Radiation Sciences, Diagnostic Radiology, Umeå University, Umeå
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Loebel A, Cucchiaro J, Sarma K, Xu L, Hsu C, Kalali AH, Pikalov A, Potkin SG. Efficacy and safety of lurasidone 80 mg/day and 160 mg/day in the treatment of schizophrenia: a randomized, double-blind, placebo- and active-controlled trial. Schizophr Res 2013; 145:101-9. [PMID: 23415311 DOI: 10.1016/j.schres.2013.01.009] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 01/09/2013] [Accepted: 01/11/2013] [Indexed: 12/22/2022]
Abstract
OBJECTIVE This study was designed to evaluate the short-term efficacy and safety of once-daily lurasidone (80 mg/day and 160 mg/day) in the treatment of an acute exacerbation of schizophrenia. METHODS Participants, who were recently admitted inpatients with schizophrenia with an acute exacerbation of psychotic symptoms, were randomly assigned to 6 weeks of fixed-dose, double-blind treatment with lurasidone 80 mg (n=125), lurasidone 160 mg (n=121), quetiapine XR 600 mg (QXR-600 mg; n=119; active control included to test for assay sensitivity), or placebo (n=121), all dosed once daily in the evening. Efficacy was evaluated using a mixed-model repeated-measures analysis of the change from Baseline to Week 6 in Positive and Negative Syndrome Scale (PANSS) total score (the primary efficacy measure) and Clinical Global Impressions severity (CGI-S) score (the key secondary efficacy measure). RESULTS Treatment with both doses of lurasidone or with QXR-600 mg was associated with significantly greater improvement at Week 6 on PANSS total score, PANSS positive and negative subscale scores, and CGI-S score compared with placebo. The endpoint responder rate (≥ 20% improvement in PANSS total score) was higher in subjects treated with lurasidone 80 mg (65%; p<0.001), lurasidone 160 mg (79%; p<0.001), and QXR-600 mg (79%; p<0.001) compared with placebo (41%). The proportion of patients experiencing ≥ 7% weight gain was 4% for each lurasidone group, 15% for the QXR-600 mg group, and 3% for the placebo group. Endpoint changes in levels of cholesterol, triglycerides, and low-density lipoprotein (LDL) cholesterol were comparable for both lurasidone groups and placebo, while the QXR-600 mg group showed a significant median increase compared with the placebo group in levels of cholesterol (p<0.001), LDL cholesterol (p<0.01), and triglycerides (p<0.05). CONCLUSIONS Lurasidone 80 mg and 160 mg doses administered once-daily in the evening, were safe and effective treatments for subjects with acute schizophrenia, with increased response rates observed at the higher dose. Dose-related adverse effects were limited, and both doses were generally well-tolerated.
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11
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Delille HK, Mezler M, Marek GJ. The two faces of the pharmacological interaction of mGlu2 and 5-HT₂A - relevance of receptor heterocomplexes and interaction through functional brain pathways. Neuropharmacology 2013; 70:296-305. [PMID: 23466331 DOI: 10.1016/j.neuropharm.2013.02.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 02/01/2013] [Accepted: 02/04/2013] [Indexed: 11/28/2022]
Abstract
Important functional interactions between the metabotropic glutamate 2 (mGlu2) and 5-hydroxytryptamine2A (5-HT₂A) neurotransmitter receptors have been established based on electrophysiological, biochemical and behavioral evidence. Over the last several years, dimerization between 5-HT₂A and mGlu2 receptors has been proposed to account for the functional cross-talk between these two receptors in the prefrontal cortex. The pros and cons for the existence of a heteromeric complex between 5-HT₂A and mGlu2 receptors will be reviewed here. First, the fundamental criteria needing to establish evidence for heteromeric complexes will be reviewed. Then, the in vitro evidence for and against heteromeric complexes between 5-HT₂A and mGlu2 receptors will be discussed in regard to physical and functional interactions. Finally, the data with native in situ mGlu2 and 5-HT₂A receptors will be discussed with respect to whether heteromeric complexes or a simple functional interaction between two distinct GPCRs based on brain network activity is the more simple explanation for a range of in vivo data.
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Affiliation(s)
- Hannah K Delille
- Abbott Diagnostics Division, Max-Planck-Ring 2, 65205 Wiesbaden, Germany
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Antipsychotics, dopamine D₂ receptor occupancy and clinical improvement in schizophrenia: a meta-analysis. Schizophr Res 2012; 140:214-20. [PMID: 22795368 DOI: 10.1016/j.schres.2012.06.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 06/14/2012] [Accepted: 06/15/2012] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Treatment of schizophrenia (SCZ) was revolutionized with the development of the antipsychotic medications. Although imaging studies have linked antipsychotic D₂ receptor occupancy and clinical response in SCZ, heterogeneity between cohorts and methods has made it challenging to generalize findings across studies. The main objective of this meta-analysis was to analyze the relationship between in vivo estimation of typical and atypical antipsychotic D₂ receptor occupancy and treatment response in SCZ. METHODS Using the keywords "dopamine D₂ receptor occupancy," "schizophrenia," "PET/SPECT" and "antipsychotics," and further refining our search to journal articles with information on % striatal D₂ occupancy and % change in clinical symptoms as indexed by either the BPRS or the PANSS, our final analysis consisted of 16 imaging studies (20 cohorts; N=206). RESULTS The first step of the meta-analysis confirmed the positive relationship between antipsychotic medication and clinical improvement in SCZ (ES=1.36; 95% CI: 1.13-1.60). The second step of our analysis revealed that when D₂ occupancy was limited to less than 80% in order to control for the appearance of extrapyramidal symptoms, high D₂ occupancy was correlated with reduction in clinical scores (r=0.4, p<0.001) for medications other than clozapine or quetiapine. CONCLUSIONS Our results suggest that D₂ occupancy is a contributing factor for the mechanism of antipsychotic effect in SCZ for some but not all antipsychotic medications.
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13
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Aginagalde M, Gómez-Vallejo V, Vara Y, Cossío FP, Llop J. Synthesis of 11C-labeled Kendine 91, a histone deacetylase inhibitor. Appl Radiat Isot 2012; 70:2552-7. [PMID: 22871301 DOI: 10.1016/j.apradiso.2012.05.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 10/04/2011] [Accepted: 05/29/2012] [Indexed: 11/27/2022]
Abstract
In the present paper, the synthesis of (11)C-labeled Kendine 91 (a HDAC inhibitor which has shown in vitro and in vivo activity in HCT 116 and MOLT 4 human cancer cell lines) is described for the first time. The radiosynthesis has been approached by reaction of the non-radioactive precursor 6-((3-(4-hydroxyphenyl)-5-phenyl-1H-pyrrole-2-carboxamide))hexanehydroxamic acid with [(11)C]CH(3)I in basic media. Despite the presence of more than one reactive site in the chemical structure of the precursor, acceptable radiochemical yield (8.2±2.1%, decay corrected to the end of bombardment), specific activity (28.2±9.4 GBq/μmol) and radiochemical purity values (>95%) were obtained in reasonably short preparation times (~40 min). Despite the moderate radiochemical yield, final radioactivity and radioactivity concentration values (1.8±0.3 GBq and 180 MBq/ml, respectively) should be sufficient for putative in vivo studies in animals.
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Affiliation(s)
- Maialen Aginagalde
- Departamento de Química Orgánica I, Facultad de Química, Universidad del País Vasco--Euskal Herriko Unibertsitatea, Edificio Joxe Mari Korta, Sebastián, Spain
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Receptor targets for antidepressant therapy in bipolar disorder: an overview. J Affect Disord 2012; 138:222-38. [PMID: 21601292 DOI: 10.1016/j.jad.2011.04.043] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Accepted: 04/27/2011] [Indexed: 11/20/2022]
Abstract
The treatment of bipolar depression is one of the most challenging issues in contemporary psychiatry. Currently only quetiapine and the olanzapine-fluoxetine combination are officially approved by the FDA against this condition. The neurobiology of bipolar depression and the possible targets of bipolar antidepressant therapy remain relatively elusive. We performed a complete and systematic review to identify agents with definite positive or negative results concerning efficacy followed by a second systematic review to identify the pharmacodynamic properties of these agents. The comparison of properties suggests that the stronger predictors for antidepressant efficacy in bipolar depression were norepinephrine alpha-1, dopamine D1 and histamine antagonism, followed by 5-HT2A, muscarinic and dopamine D2 and D3 antagonism and eventually by norepinephrine reuptake inhibition and 5HT-1A agonism. Serotonin reuptake which constitutes the cornerstone in unipolar depression treatment does not seem to play a significant role for bipolar depression. Our exhaustive review is compatible with a complex model with multiple levels of interaction between the major neurotransmitter systems without a single target being either necessary or sufficient to elicit the antidepressant effect in bipolar depression.
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Uchida H, Takeuchi H, Graff-Guerrero A, Suzuki T, Watanabe K, Mamo DC. Dopamine D2 receptor occupancy and clinical effects: a systematic review and pooled analysis. J Clin Psychopharmacol 2011; 31:497-502. [PMID: 21694629 DOI: 10.1097/jcp.0b013e3182214aad] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Positron emission tomography (PET) studies proposed a therapeutic window of D2 receptor occupancy (65%-80%) of antipsychotics for the treatment of schizophrenia in young adults. However, this conclusion has been drawn from clinical PET studies using small sample sizes (<20). Prospective PET studies that measured D2 occupancy levels and assessed extrapyramidal side effects (EPS) and/or treatment response induced by antipsychotics (excluding partial agonists) were identified, using MEDLINE and EMBASE (last search: March 2010). Individual subjects were divided into 2 groups based on EPS status (ie, presence or lack of newly emergent EPS) and treatment response (ie, a ≥ 25% or ≥ 50% reduction in the Positive and Negative Syndrome Scale or Brief Psychiatric Rating Scale). To evaluate the performance of this binary classification, sensitivity, specificity, and accuracy of consecutive cutoff points in the D2 occupancy were calculated: Accuracy = (True Positive + True Negative) / Total N. Twelve studies, including a total of 82 subjects, were included in our analyses. The cutoff points associated with 0.5 or greater in both sensitivity and specificity with the greatest accuracy were 77% to 78% for EPS, 60% for a 25% or greater symptom reduction, and 72% for a 50% or greater symptom reduction. These findings support the presence of a therapeutic window of 60% to 78% D2 occupancy of antipsychotics in young adults with schizophrenia and may suggest the presence of a continuum of effectiveness with increasing occupancy within this therapeutic window.
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Affiliation(s)
- Hiroyuki Uchida
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan.
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Johnson M, Kozielska M, Pilla Reddy V, Vermeulen A, Li C, Grimwood S, de Greef R, Groothuis GMM, Danhof M, Proost JH. Mechanism-based pharmacokinetic-pharmacodynamic modeling of the dopamine D2 receptor occupancy of olanzapine in rats. Pharm Res 2011; 28:2490-504. [PMID: 21647790 PMCID: PMC3170473 DOI: 10.1007/s11095-011-0477-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Accepted: 05/09/2011] [Indexed: 01/16/2023]
Abstract
Purpose A mechanism-based PK-PD model was developed to predict the time course of dopamine D2 receptor occupancy (D2RO) in rat striatum following administration of olanzapine, an atypical antipsychotic drug. Methods A population approach was utilized to quantify both the pharmacokinetics and pharmacodynamics of olanzapine in rats using the exposure (plasma and brain concentration) and D2RO profile obtained experimentally at various doses (0.01–40 mg/kg) administered by different routes. A two-compartment pharmacokinetic model was used to describe the plasma pharmacokinetic profile. A hybrid physiology- and mechanism-based model was developed to characterize the D2 receptor binding in the striatum and was fitted sequentially to the data. The parameters were estimated using nonlinear mixed-effects modeling . Results Plasma, brain concentration profiles and time course of D2RO were well described by the model; validity of the proposed model is supported by good agreement between estimated association and dissociation rate constants and in vitro values from literature. Conclusion This model includes both receptor binding kinetics and pharmacokinetics as the basis for the prediction of the D2RO in rats. Moreover, this modeling framework can be applied to scale the in vitro and preclinical information to clinical receptor occupancy.
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Affiliation(s)
- Martin Johnson
- Department of Pharmacokinetics, Toxicology and Targeting, University of Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
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Predicting dopamine D₂ receptor occupancy from plasma levels of antipsychotic drugs: a systematic review and pooled analysis. J Clin Psychopharmacol 2011; 31:318-25. [PMID: 21508857 DOI: 10.1097/jcp.0b013e318218d339] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Measuring dopamine D₂ receptor occupancy levels using positron emission tomography (PET) is still widely unavailable. The objective of this study was to evaluate the accuracy of predicting D2 occupancy from the antipsychotic plasma level in patients with schizophrenia. Positron emission tomographic studies that measured plasma levels of antipsychotics and their corresponding D₂ occupancy levels were identified, using MEDLINE and EMBASE (last search: March 2010). Antipsychotics that were investigated in a total of 20 subjects or more were included. All data points for each antipsychotic were fit to a one-site binding model to estimate the total plasma concentration of each antipsychotic associated with a 50% occupancy (ED₅₀) of brain D₂ receptors. The mean prediction error and the root mean squared prediction error were used to measure the predictive performance of individual D₂ receptor occupancies from plasma drug levels derived from a one-site occupancy model using an ED₅₀ value calculated for each data point. A total of 34 treatment arms from 23 studies involving 281 subjects were included. The mean (95% confidence interval) prediction errors and root squared prediction errors were as low as 0.0 (-1.8 to 1.8) and 8.9 (7.6-10.2) for risperidone (n = 98); 0.0 (-3.5 to 3.5) and 15.1 (12.9-17.3) for clozapine (n = 75); -0.1 (-1.2 to 1.2), 0.0 (-1.9 to 1.9), and 4.6 (3.5-5.8) for olanzapine (n = 42); 0.1 (-3.4 to 3.5) and 9.9 (7.3-12.5) for haloperidol (n = 35); and -0.1 (-3.3 to 3.1) and 12.3 (8.8-15.7) for ziprasidone (n = 31), respectively. These findings suggest that D₂ occupancy of antipsychotics could be estimated with a high degree of accuracy using widely available plasma levels.
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Catafau AM, Bullich S, Nucci G, Burgess C, Gray F, Merlo-Pich E. Contribution of SPECT Measurements of D2 and 5-HT2A Occupancy to the Clinical Development of the Antipsychotic SB-773812. J Nucl Med 2011; 52:526-34. [DOI: 10.2967/jnumed.110.081885] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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Abstract
In psychiatry, neuroimaging facilitates the diagnosis of psychiatric disorders and the development of new medications. It is used to detect structural lesions causing psychosis and to differentiate depression from neurodegenerative disorders or brain tumors. Functional neuroimaging, mostly in the form of molecular neuroimaging with positron emission tomography or single photon emission tomography, facilitates the identification of therapeutic targets, the determination of the dose of a new drug needed to occupy its target in the brain, and the selection of patients for clinical trials.
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Affiliation(s)
- Joseph C Masdeu
- Section on Integrative Neuroimaging, Intramural Research Program, National Institutes of Health (NIH/NIMH-CBDB), Bethesda, Maryland 20892-1365, 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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Spiros A, Carr R, Geerts H. Not all partial dopamine D(2) receptor agonists are the same in treating schizophrenia. Exploring the effects of bifeprunox and aripiprazole using a computer model of a primate striatal dopaminergic synapse. Neuropsychiatr Dis Treat 2010; 6:589-603. [PMID: 20856922 PMCID: PMC2938308 DOI: 10.2147/ndt.s12460] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Species differences in physiology and unique active human metabolites contribute to the limited predictive value of preclinical rodent models for many central nervous system (CNS) drugs. In order to explore possible drivers for this translational disconnect, we developed a computer model of a dopaminergic synapse that simulates the competition among three agents and their binding to pre- and postsynaptic receptors, based on the affinities for their targets and their actual concentrations. The model includes presynaptic autoreceptor effects on neurotransmitter release and modulation by presynaptic firing frequency and is calibrated with actual experimental data on free dopamine levels in the striatum of the rodent and the primate. Using this model, we simulated the postsynaptic dopamine D(2) receptor activation levels of bifeprunox and aripiprazole, two relatively similar dopamine D(2) receptor agonists. The results indicate a substantial difference in dose-response for the two compounds when applying primate calibration parameters as opposed to rodent calibration parameters. In addition, when introducing the major human and rodent metabolites of aripiprazole with their specific pharmacological activities, the model predicts that while bifeprunox would result in a higher postsynaptic D(2) receptor antagonism in the rodent, aripiprazole would result in a higher D(2) receptor antagonism in the primate model. Furthermore, only the highest dose of aripiprazole, but not bifeprunox, reaches postsynaptic functional D(2) receptor antagonism similar to 4 mg haloperidol in the primate model. The model further identifies a limited optimal window of functionality for dopamine D(2) receptor partial agonists. These results suggest that computer modeling of key CNS processes, using well-validated calibration paradigms, can increase the predictive value in the clinical setting of preclinical animal model outcomes.
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Affiliation(s)
- Athan Spiros
- In Silico Biosciences, Berwyn Inc, 686 Westwind, Berwyn, PA,USA
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In Vitro and Initial In Vivo Evaluation of 68Ga-Labeled Transferrin Receptor (TfR) Binding Peptides as Potential Carriers for Enhanced Drug Transport into TfR Expressing Cells. Mol Imaging Biol 2010; 13:332-41. [DOI: 10.1007/s11307-010-0329-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Bullich S, Cot A, Gallego J, Gunn R, Suárez M, Pavía J, Ros D, Laruelle M, Catafau A. Impact of scatter correction on D2 receptor occupancy measurements using 123I-IBZM SPECT: Comparison to 11C-Raclopride PET. Neuroimage 2010; 50:1511-8. [DOI: 10.1016/j.neuroimage.2010.01.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Revised: 12/28/2009] [Accepted: 01/07/2010] [Indexed: 10/20/2022] Open
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Willeit M, Praschak-Rieder N. Imaging the effects of genetic polymorphisms on radioligand binding in the living human brain: A review on genetic neuroreceptor imaging of monoaminergic systems in psychiatry. Neuroimage 2010; 53:878-92. [PMID: 20399868 DOI: 10.1016/j.neuroimage.2010.04.030] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Revised: 04/08/2010] [Accepted: 04/12/2010] [Indexed: 12/16/2022] Open
Abstract
Imaging genetics is a research field that describes the impact of genetic risk variants on brain structure and function. While magnetic resonance based imaging techniques are able to provide complex information on a system level, positron emission tomography (PET) and single photon emission computer tomography (SPECT) allow for determination of distribution and density of single receptor molecules in the human brain. Major psychiatric disorders are highly heritable, and have been associated with a dysregulation in brain dopamine and serotonin systems. Understanding the role of genetic polymorphisms within these neurotransmitter systems on brain phenotype is essential. This review tries to cover the literature on the impact of gene variants implicated in psychiatric disorders on serotonin, dopamine, and MAO-A radioligand binding in living humans. The majority of PET and SPECT studies investigated the role of polymorphisms within genes coding for the serotonin and dopamine transporters, the serotonin 1A receptor, and the dopamine D2 receptor on G protein coupled receptors or transporter proteins critically involved in serotonin or dopamine neurotransmission. Other studies investigated the impact of variants in genes for monoamine oxidase-A (MAO-A) or brain derived neurotrophic factor on monoamine transporters, receptors, or MAO-A activity. Two main findings in healthy subjects emerge from the current literature: one is an increased binding of the selective ligand [(11)C]DASB to serotonin transporters in subjects homozygous for the triallelic 5-HTTLPR LA allele. The other one is decreased binding of the radioligand [(11)C]raclopride to dopamine D2 receptors in D2 Taq1 A1 allele carriers. Other findings reported are highly interesting but require independent replication.
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Affiliation(s)
- Matthäus Willeit
- Division of Biological Psychiatry, Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria.
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Measurement of the pharmacokinetics and pharmacodynamics of neuroactive compounds. Neurobiol Dis 2010; 37:38-47. [DOI: 10.1016/j.nbd.2009.09.025] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2009] [Revised: 09/29/2009] [Accepted: 09/30/2009] [Indexed: 11/24/2022] Open
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Thompson JL, Urban N, Abi-Dargham A. How have developments in molecular imaging techniques furthered schizophrenia research? ACTA ACUST UNITED AC 2009; 1:135-153. [PMID: 21243081 DOI: 10.2217/iim.09.22] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Molecular imaging techniques have led to significant advances in understanding the pathophysiology of schizophrenia and contributed to knowledge regarding potential mechanisms of action of the drugs used to treat this illness. The aim of this article is to provide a review of the major findings related to the application of molecular imaging techniques that have furthered schizophrenia research. This article focuses specifically on neuroreceptor imaging studies with PET and SPECT. After providing a brief overview of neuroreceptor imaging methodology, we consider relevant findings from studies of receptor availability, and dopamine synthesis and release. Results are discussed in the context of current hypotheses regarding neurochemical alterations in the illness. We then selectively review pharmacological occupancy studies and the role of neuroreceptor imaging in drug development for schizophrenia.
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Affiliation(s)
- Judy L Thompson
- Department of Psychiatry, Columbia University and New York State Psychiatric Institute, 1051 Riverside Drive, Unit 31, New York, NY 10032, USA
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