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Dalley JW, Fryer TD, Aigbirhio FI, Brichard L, Richards HK, Hong YT, Baron JC, Everitt BJ, Robbins TW. Modelling human drug abuse and addiction with dedicated small animal positron emission tomography. Neuropharmacology 2008; 56 Suppl 1:9-17. [PMID: 18614184 DOI: 10.1016/j.neuropharm.2008.05.029] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2008] [Revised: 05/16/2008] [Accepted: 05/24/2008] [Indexed: 11/19/2022]
Abstract
Drug addiction is a chronically relapsing brain disorder, which causes substantial harm to the addicted individual and society as a whole. Despite considerable research we still do not understand why some people appear particularly disposed to drug abuse and addiction, nor do we understand how frequently co-morbid brain disorders such as depression and attention-deficit hyperactivity disorder (ADHD) contribute causally to the emergence of addiction-like behaviour. In recent years positron emission tomography (PET) has come of age as a translational neuroimaging technique in the study of drug addiction, ADHD and other psychopathological states in humans. PET provides unparalleled quantitative assessment of the spatial distribution of radiolabelled molecules in the brain and because it is non-invasive permits longitudinal assessment of physiological parameters such as binding potential in the same subject over extended periods of time. However, whilst there are a burgeoning number of human PET experiments in ADHD and drug addiction there is presently a paucity of PET imaging studies in animals despite enormous advances in our understanding of the neurobiology of these disorders based on sophisticated animal models. This article highlights recent examples of successful cross-species convergence of findings from PET studies in the context of drug addiction and ADHD and identifies how small animal PET can more effectively be used to model complex psychiatric disorders involving at their core impaired behavioural self-control.
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Affiliation(s)
- Jeffrey W Dalley
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK.
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Vandenhende F, Renard D, Nie Y, Kumar A, Miller J, Tauscher J, Witcher J, Zhou Y, Wong DF. Bayesian Hierarchical Modeling of Receptor Occupancy in PET Trials. J Biopharm Stat 2008; 18:256-72. [DOI: 10.1080/10543400701697158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- F. Vandenhende
- a Global Statistics , Lilly Research Laboratories, Mont-Saint-Guibert , Belgium
| | - D. Renard
- a Global Statistics , Lilly Research Laboratories, Mont-Saint-Guibert , Belgium
| | - Y. Nie
- b Biostatistics Department , Universiteit Hasselt , Diepenbeek, Belgium
| | - A. Kumar
- c School of Medicine , PET Center, John Hopkins , Baltimore, USA
| | - J. Miller
- d Clinical Pharmacology , Lilly Research Laboratories , Indianapolis, USA
| | - J. Tauscher
- e Imaging Department , Lilly Research Laboratories , Indianapolis, USA
| | - J. Witcher
- f Global PK/PD , Lilly Research Laboratories , Indianapolis, USA
| | - Y. Zhou
- c School of Medicine , PET Center, John Hopkins , Baltimore, USA
| | - D. F. Wong
- c School of Medicine , PET Center, John Hopkins , Baltimore, USA
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Gallezot JD, Weinzimmer D, Nabulsi N, Lin SF, Fowles K, Maguire P, Carson R, Ding YS. Evaluation of [11C]MRB for receptor occupancy studies of norepinephrine transporters. Neuroimage 2008. [DOI: 10.1016/j.neuroimage.2008.04.223] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Biodistribution and radiation dosimetry of the norepinephrine transporter radioligand (S,S)-[18F]FMeNER-D2: a human whole-body PET study. Eur J Nucl Med Mol Imaging 2007; 35:630-6. [DOI: 10.1007/s00259-007-0622-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2007] [Accepted: 09/28/2007] [Indexed: 10/22/2022]
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Zeng F, Jarkas N, Stehouwer JS, Voll RJ, Owens MJ, Kilts CD, Nemeroff CB, Goodman MM. Synthesis, in vitro characterization, and radiolabeling of reboxetine analogs as potential PET radioligands for imaging the norepinephrine transporter. Bioorg Med Chem 2007; 16:783-93. [PMID: 17983754 DOI: 10.1016/j.bmc.2007.10.025] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2007] [Revised: 10/02/2007] [Accepted: 10/10/2007] [Indexed: 10/22/2022]
Abstract
Six new (S,S)-enantiomers of reboxetine derivatives were synthesized and their binding affinities were determined via competition binding assays in cells expressing the human norepinephrine transporter (NET), serotonin transporter (SERT) or dopamine transporter (DAT). All six compounds prepared exhibit high affinity for the NET (K(i)<or=2nM) and selectivity versus the SERT and DAT. Radiolabeling methods were also developed to prepare these ligands in moderate to high radiochemical yield with high radiochemical purity via O- or S-methylation with [(11)C]CH(3)I, or O-alkylation with [(18)F]fluoroethyl brosylate or [(18)F]fluoropropyl brosylate, and their logP(7.4) was measured. These new C-11- and F-18-labeled tracers will be utilized in comparative microPET studies to evaluate their potential as PET radioligands for imaging brain NET in nonhuman primates.
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Affiliation(s)
- Fanxing Zeng
- Department of Radiology, Division of Radiological Sciences, Emory University, Atlanta, GA 30322, USA
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Takano A, Gulyás B, Varrone A, Karlsson P, Schou M, Airaksinen AJ, Vandenhende F, Tauscher J, Halldin C. Imaging the norepinephrine transporter with positron emission tomography: initial human studies with (S,S)-[18F]FMeNER-D2. Eur J Nucl Med Mol Imaging 2007; 35:153-7. [PMID: 17909794 DOI: 10.1007/s00259-007-0598-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2007] [Accepted: 08/02/2007] [Indexed: 11/29/2022]
Abstract
INTRODUCTION (S,S)-[(18)F]FMeNER-D(2) is a recently developed positron emission tomography (PET) ligand for in vivo quantification of norepinephrine transporter. A monkey occupancy study with the radioligand indicated that (S,S)-[(18)F]FMeNER-D(2) can be useful for quantitative PET analysis. In this preliminary study, regional distributions in the living human brain were evaluated. MATERIALS AND METHODS Brain PET measurements were performed for a total of 255 min after the injection of 188.3 +/- 5.7 MBq of (S,S)-[(18)F]FMeNER-D(2) in four healthy male subjects. Regions of interests were drawn on the thalamus and the caudate in the coregistered MRI/PET images. RESULTS (S,S)-[(18)F]FMeNER-D(2) displayed good brain penetration and selective retention in regions rich in norepinephrine reuptake sites. The transient peak equilibrium was reached during the PET measurements. The ratios of radioactivity uptake in the thalamus to that in the caudate were 1.50 +/- 0.06 for the time period of 90-255 min. CONCLUSION The present preliminary investigation indicates that (S,S)-[(18)F]FMeNER-D(2) has suitable characteristics for probing the norepinephrine reuptake system with PET in the human brain.
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Affiliation(s)
- Akihiro Takano
- Psychiatry Section, Department of Clinical Neuroscience, Karolinska Institutet, 171 76, Stockholm, Sweden.
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Huang Y, Williams WA. Enhanced selective serotonin re-uptake inhibitors as antidepressants: 2004 – 2006. Expert Opin Ther Pat 2007; 17:889-907. [DOI: 10.1517/13543776.17.8.889] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Logan J, Wang GJ, Telang F, Fowler JS, Alexoff D, Zabroski J, Jayne M, Hubbard B, King P, Carter P, Shea C, Xu Y, Muench L, Schlyer D, Learned-Coughlin S, Cosson V, Volkow ND, Ding YS. Imaging the norepinephrine transporter in humans with (S,S)-[11C]O-methyl reboxetine and PET: problems and progress. Nucl Med Biol 2007; 34:667-79. [PMID: 17707807 DOI: 10.1016/j.nucmedbio.2007.03.013] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2007] [Revised: 03/03/2007] [Accepted: 03/27/2007] [Indexed: 11/22/2022]
Abstract
UNLABELLED Results from human studies with the PET radiotracer (S,S)-[(11)C]O-methyl reboxetine ([(11)C](S,S)-MRB), a ligand targeting the norepinephrine transporter (NET), are reported. Quantification methods were determined from test/retest studies, and sensitivity to pharmacological blockade was tested with different doses of atomoxetine (ATX), a drug that binds to the NET with high affinity (K(i)=2-5 nM). METHODS Twenty-four male subjects were divided into different groups for serial 90-min PET studies with [(11)C](S,S)-MRB to assess reproducibility and the effect of blocking with different doses of ATX (25, 50 and 100 mg, po). Region-of-interest uptake data and arterial plasma input were analyzed for the distribution volume (DV). Images were normalized to a template, and average parametric images for each group were formed. RESULTS [(11)C](S,S)-MRB uptake was highest in the thalamus (THL) and the midbrain (MBR) [containing the locus coeruleus (LC)] and lowest for the caudate nucleus (CDT). The CDT, a region with low NET, showed the smallest change on ATX treatment and was used as a reference region for the DV ratio (DVR). The baseline average DVR was 1.48 for both the THL and MBR with lower values for other regions [cerebellum (CB), 1.09; cingulate gyrus (CNG) 1.07]. However, more accurate information about relative densities came from the blocking studies. MBR exhibited greater blocking than THL, indicating a transporter density approximately 40% greater than THL. No relationship was found between DVR change and plasma ATX level. Although the higher dose tended to induce a greater decrease than the lower dose for MBR (average decrease for 25 mg=24+/-7%; 100 mg=31+/-11%), these differences were not significant. The different blocking between MBR (average decrease=28+/-10%) and THL (average decrease=17+/-10%) given the same baseline DVR indicates that the CDT is not a good measure for non-NET binding in both regions. Threshold analysis of the difference between the average baseline DV image and the average blocked image showed the expected NET distribution with the MBR (LC) and hypothalamus>THL>CNG and CB, as well as a significant change in the supplementary motor area. DVR reproducibility for the different brain regions was approximately 10%, but intersubject variability was large. CONCLUSIONS The highest density of NETs was found in the MBR where the LC is located, followed by THL, whereas the lowest density was found in basal ganglia (lowest in CDT), consistent with the regional localization of NETs in the nonhuman primate brain. While all three doses of ATX were found to block most regions, no significant differences between doses were found for any region, although the average percent change across subjects of the MBR did correlate with ATX dose. The lack of a dose effect could reflect a low signal-to-noise ratio coupled with the possibility that a sufficient number of transporters were blocked at the lowest dose and further differences could not be detected. However, since the lowest (25 mg) dose is less than the therapeutic doses used in children for the treatment of attention-deficit/hyperactivity disorder ( approximately 1.0 mg/kg/day), this would suggest that there may be additional targets for ATX's therapeutic actions.
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Affiliation(s)
- Jean Logan
- Medical Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
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Severance AJ, Milak MS, Kumar JSD, Prabhakaran J, Majo VJ, Simpson NR, Van Heertum RL, Arango V, Mann JJ, Parsey RV. In vivo assessment of [11C]MRB as a prospective PET ligand for imaging the norepinephrine transporter. Eur J Nucl Med Mol Imaging 2006; 34:688-693. [PMID: 17180600 DOI: 10.1007/s00259-006-0312-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2006] [Accepted: 10/12/2006] [Indexed: 11/28/2022]
Abstract
PURPOSE Antagonism of norepinephrine reuptake is now an important pharmacological strategy in the treatment of anxiety and depressive disorders, and many antidepressants have substantial potential occupancy of the norepinephrine transporter (NET) at recommended dosages. Despite the importance of understanding this transporter's role in psychiatric disease and treatment, a suitable radioligand for studying NET has been slow to emerge. (S,S)-Methylreboxetine (MRB) is among the more promising ligands recently adapted for positron emission tomography (PET), and the present study aimed to evaluate its potential for use in higher primates. METHODS Affinities for various brain targets were determined in vitro. PET studies were conducted in baboon under both test-retest and blocking conditions using 1 mg/kg nisoxetine. RESULTS MRB has sixfold higher affinity for NET than the serotonin transporter, and negligible affinity for other sites. PET studies in baboons showed little regional heterogeneity in binding and were minimally affected by pretreatment with the NET antagonist nisoxetine. CONCLUSION Despite improvement over previous ligands for imaging NET in vivo, the low signal to noise ratio indicates [(11)C]MRB lacks sensitivity and reliability as a PET radiotracer in humans.
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Affiliation(s)
- Alin J Severance
- Division of Brain Imaging, Department of Neuroscience, New York State Psychiatric Institute, 1051 Riverside Drive, P.O. Box #42, New York, NY, 10032, USA
| | - Matthew S Milak
- Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA
- Division of Brain Imaging, Department of Neuroscience, New York State Psychiatric Institute, 1051 Riverside Drive, P.O. Box #42, New York, NY, 10032, USA
| | - J S Dileep Kumar
- Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA
- Division of Brain Imaging, Department of Neuroscience, New York State Psychiatric Institute, 1051 Riverside Drive, P.O. Box #42, New York, NY, 10032, USA
| | - Jaya Prabhakaran
- Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Vattoly J Majo
- Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Norman R Simpson
- Department of Radiology, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Ronald L Van Heertum
- Department of Radiology, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Victoria Arango
- Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA
- Division of Brain Imaging, Department of Neuroscience, New York State Psychiatric Institute, 1051 Riverside Drive, P.O. Box #42, New York, NY, 10032, USA
| | - J John Mann
- Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA
- Department of Radiology, Columbia University College of Physicians and Surgeons, New York, NY, USA
- Division of Brain Imaging, Department of Neuroscience, New York State Psychiatric Institute, 1051 Riverside Drive, P.O. Box #42, New York, NY, 10032, USA
| | - Ramin V Parsey
- Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA.
- Division of Brain Imaging, Department of Neuroscience, New York State Psychiatric Institute, 1051 Riverside Drive, P.O. Box #42, New York, NY, 10032, USA.
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