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Nikolaus S, Chao OY, Henke J, Beu M, Fazari B, Almeida FR, Abdel-Hafiz L, Antke C, Hautzel H, Mamlins E, Müller HW, Huston JP, von Gall C, Giesel FL. 5-HT 1A and 5-HT 2A receptor effects on recognition memory, motor/exploratory behaviors, emotionality and regional dopamine transporter binding in the rat. Behav Brain Res 2024; 469:115051. [PMID: 38777263 DOI: 10.1016/j.bbr.2024.115051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 05/16/2024] [Accepted: 05/16/2024] [Indexed: 05/25/2024]
Abstract
Both dopamine (DA) and serotonin (5-HT) play key roles in numerous functions including motor control, stress response and learning. So far, there is scarce or conflicting evidence about the effects of 5-HT1A and 5-HT2A receptor (R) agonists and antagonists on recognition memory in the rat. This also holds for their effect on cerebral DA as well as 5-HT release. In the present study, we assessed the effects of the 5-HT1AR agonist 8-OH-DPAT and antagonist WAY100,635 and the 5-HT2AR agonist DOI and antagonist altanserin (ALT) on rat behaviors. Moreover, we investigated their impact on monoamine efflux by measuring monoamine transporter binding in various regions of the rat brain. After injection of either 8-OH-DPAT (3 mg/kg), WAY100,635 (0.4 mg/kg), DOI (0.1 mg/kg), ALT (1 mg/kg) or the respective vehicle (saline, DMSO), rats underwent an object and place recognition memory test in the open field. Upon the assessment of object exploration, motor/exploratory parameters and feces excretion, rats were administered the monoamine transporter radioligand N-o-fluoropropyl-2b-carbomethoxy-3b-(4-[123I]iodophenyl)-nortropane ([123I]-FP-CIT; 8.9 ± 2.6 MBq) into the tail vein. Regional radioactivity accumulations in the rat brain were determined post mortem. Compared vehicle, administration of 8-OH-DPAT impaired memory for place, decreased rearing behavior, and increased ambulation as well as head-shoulder movements. DOI administration led to a reduction in rearing behavior but an increase in head-shoulder motility relative to vehicle. Feces excretion was diminished after ALT relative to vehicle. Dopamine transporter (DAT) binding was increased in the caudateputamen (CP), but decreased in the nucleus accumbens (NAC) after 8-OH-DPAT relative to vehicle. Moreover, DAT binding was decreased in the NAC after ALT relative to vehicle. Findings indicate that 5-HT1AR inhibition and 5-HT2AR activation may impair memory for place. Furthermore, results imply associations not only between recognition memory, motor/exploratory behavior and emotionality but also between the respective parameters and the levels of available DA in CP and NAC.
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MESH Headings
- Animals
- Dopamine Plasma Membrane Transport Proteins/metabolism
- Male
- Recognition, Psychology/drug effects
- Recognition, Psychology/physiology
- Exploratory Behavior/drug effects
- Exploratory Behavior/physiology
- Rats
- Receptor, Serotonin, 5-HT1A/metabolism
- Receptor, Serotonin, 5-HT1A/drug effects
- Receptor, Serotonin, 5-HT2A/metabolism
- Receptor, Serotonin, 5-HT2A/drug effects
- Motor Activity/drug effects
- Motor Activity/physiology
- Brain/metabolism
- Brain/drug effects
- Emotions/drug effects
- Emotions/physiology
- Serotonin 5-HT1 Receptor Agonists/pharmacology
- Serotonin 5-HT2 Receptor Agonists/pharmacology
- Rats, Wistar
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Affiliation(s)
- Susanne Nikolaus
- Clinic of Nuclear Medicine, Medical Faculty, Heinrich-Heine University, Moorenstr. 5, Düsseldorf D-40225, Germany.
| | - Owen Y Chao
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN 55812, USA
| | - Jan Henke
- Clinic of Nuclear Medicine, Medical Faculty, Heinrich-Heine University, Moorenstr. 5, Düsseldorf D-40225, Germany
| | - Markus Beu
- Clinic of Nuclear Medicine, Medical Faculty, Heinrich-Heine University, Moorenstr. 5, Düsseldorf D-40225, Germany
| | - Benedetta Fazari
- Institute of Anatomy II, Medical Faculty, Heinrich-Heine University, Universitätsstr. 1, Düsseldorf D-40225, Germany
| | - Filipe Rodrigues Almeida
- Institute of Anatomy II, Medical Faculty, Heinrich-Heine University, Universitätsstr. 1, Düsseldorf D-40225, Germany
| | - Laila Abdel-Hafiz
- Institute of Anatomy II, Medical Faculty, Heinrich-Heine University, Universitätsstr. 1, Düsseldorf D-40225, Germany
| | - Christina Antke
- Clinic of Nuclear Medicine, Medical Faculty, Heinrich-Heine University, Moorenstr. 5, Düsseldorf D-40225, Germany
| | - Hubertus Hautzel
- Clinic of Nuclear Medicine, University Hospital Essen, Hufelandstraße 55, Essen D-45122, Germany
| | - Eduards Mamlins
- Clinic of Nuclear Medicine, Medical Faculty, Heinrich-Heine University, Moorenstr. 5, Düsseldorf D-40225, Germany
| | - Hans-Wilhelm Müller
- Clinic of Nuclear Medicine, Medical Faculty, Heinrich-Heine University, Moorenstr. 5, Düsseldorf D-40225, Germany
| | - Joseph P Huston
- Center for Behavioural Neuroscience, Institute of Experimental Psychology, Heinrich-Heine University, Universitätsstr. 1, Düsseldorf D-40225, Germany
| | - Charlotte von Gall
- Institute of Anatomy II, Medical Faculty, Heinrich-Heine University, Universitätsstr. 1, Düsseldorf D-40225, Germany
| | - Frederik L Giesel
- Clinic of Nuclear Medicine, Medical Faculty, Heinrich-Heine University, Moorenstr. 5, Düsseldorf D-40225, Germany
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Nikolaus S, Chao OY, Beu M, Henke J, Antke C, Wang AL, Fazari B, Mamlins E, Huston JP, Giesel FL. The 5-HT 1A receptor agonist 8-OH-DPAT modulates motor/exploratory activity, recognition memory and dopamine transporter binding in the dorsal and ventral striatum. Neurobiol Learn Mem 2023; 205:107848. [PMID: 37865262 DOI: 10.1016/j.nlm.2023.107848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 10/09/2023] [Accepted: 10/18/2023] [Indexed: 10/23/2023]
Abstract
In the present studies, we assessed the effect of the 5-HT1A receptor (R) agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) on motor and exploratory behaviors, object and place recognition and dopamine transporter (DAT) and serotonin transporter (SERT) binding in the rat brain. In Experiment I, motor/exploratory behaviors were assessed in an open field after injection of either 8-OH-DPAT (0.1 and 3 mg/kg) or vehicle for 30 min without previous habituation to the open field. In Experiment II, rats underwent a 5-min exploration trial in an open field with two identical objects. After injection of either 8-OH-DPAT (0.1 and 3 mg/kg) or vehicle, rats underwent a 5-min test trial with one of the objects replaced by a novel one and the other object transferred to a novel place. Subsequently, N-o-fluoropropyl-2b-carbomethoxy-3b-(4-[123I]iodophenyl)-nortropane ([123I]FP-CIT; 11 ± 4 MBq) was injected into the tail vein. Regional radioactivity accumulations were determined post mortem with a well counter. In both experiments, 8-OH-DPAT dose-dependently increased ambulation and exploratory head-shoulder motility, whereas rearing was dose-dependently decreased. In the test rial of Experiment II, there were no effects of 8-OH-DPAT on overall activity, sitting and grooming. 8-OH-DPAT dose-dependently impaired recognition of object and place. 8-OH-DPAT (3 mg/kg) increased DAT binding in the dorsal striatum relative to both vehicle and 0.1 mg/kg 8-OH-DPAT. Furthermore, in the ventral striatum, DAT binding was decreased after 3 mg/kg 8-OH-DPAT relative to vehicle. Findings indicate that motor/exploratory behaviors, memory for object and place and regional dopamine function may be modulated by the 5-HT1AR. Since, after 8-OH-DPAT, rats exhibited more horizontal and less (exploratory) vertical motor activity, while overall activity was not different between groups, it may be inferred, that the observed impairment of object recognition was not related to a decrease of motor activity as such, but to a decrease of intrinsic motivation, attention and/or awareness, which are relevant accessories of learning. Furthermore, the present findings on 8-OH-DPAT action indicate associations not only between motor/exploratory behavior and the recognition of object and place but also between the respective parameters and the levels of available DA in dorsal and ventral striatum.
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Affiliation(s)
- Susanne Nikolaus
- Department of Nuclear Medicine, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany.
| | - Owen Y Chao
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN 55812, USA
| | - Markus Beu
- Department of Nuclear Medicine, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Jan Henke
- Department of Nuclear Medicine, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Christina Antke
- Department of Nuclear Medicine, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - An-Li Wang
- Department of Pharmacology and Toxicology, Jacob School of Medicine and Biomedical Sciences, University at Buffalo, 1021 Main Street, Buffalo, NY 14203, USA
| | - Benedetta Fazari
- Institute of Anatomy II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Universitätsstr. 1, D-40225 Düsseldorf, Germany
| | - Eduards Mamlins
- Department of Nuclear Medicine, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Joseph P Huston
- Center for Behavioural Neuroscience, Institute of Experimental Psychology, Heinrich-Heine University, Universitätsstr. 1, D-40225 Düsseldorf, Germany
| | - Frederik L Giesel
- Department of Nuclear Medicine, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
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Pak K, Seok JW, Lee MJ, Kim K, Kim IJ. Dopamine receptor and dopamine transporter in obesity: A meta-analysis. Synapse 2023; 77:e22254. [PMID: 36099576 DOI: 10.1002/syn.22254] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 08/09/2022] [Accepted: 09/08/2022] [Indexed: 01/29/2023]
Abstract
The brain plays a major role in controlling the desire to eat. This meta-analysis aimed to assess the association between dopamine receptor (DR) availability and dopamine transporter (DAT) availability, measured using positron emission tomography, and obesity. We performed a systematic search of MEDLINE (from inception to November 2020) and EMBASE (from inception to November 2020) for articles published in English using the keywords "dopamine receptor," "dopamine transporter," "obesity," and "neuroimaging." Body mass index (BMI) and the corresponding binding potential (BPND ) were extracted from figures in each study using Engauge Digitizer, version 12.1, and plotted for radiopharmaceuticals and regions of interest (ROIs). Five studies involving 119 subjects with DR and five studies including 421 subjects with DAT were eligible for inclusion in this study. In overweight or obese subjects with BMI of 25 kg/m2 or higher, DR availability from 11 C-Racloprie was negatively associated with BMI. However, DR availability from 11 C-PHNO was positively associated with BMI. DAT ratio was calculated after dividing DAT availabilities of overweight/obese BMI with mean DAT availabilities of normal BMI. The association between DAT ratio and BMI was not significant regardless of radiopharmaceuticals. In conclusion, dopamine plays a main role in the reward system with regard to obesity. Overweight and obese subjects had negative association between DR availability from 11 C-Raclopride and BMI. However, the association of DR availability with BMI was dependent on radiopharmaceuticals. DAT availability did not show the significant relationship with BMI regardless of radiopharmaceuticals.
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Affiliation(s)
- Kyoungjune Pak
- Department of Nuclear Medicine and Biomedical Research Institute, Pusan National University Hospital, Busan, Republic of Korea
| | - Ju Won Seok
- Department of Nuclear Medicine, Chung-Ang University College of Medicine, Seoul, Republic of Korea
| | - Myung Jun Lee
- Department of Neurology and Biomedical Research Institute, Pusan National University Hospital, Busan, Republic of Korea
| | - Keunyoung Kim
- Department of Nuclear Medicine and Biomedical Research Institute, Pusan National University Hospital, Busan, Republic of Korea
| | - In Joo Kim
- Department of Nuclear Medicine and Biomedical Research Institute, Pusan National University Hospital, Busan, Republic of Korea
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Pak K, Seo S, Lee MJ, Kim K, Suh S, Lee J, Kim SJ, Kim IJ. Hedonic Rating of Sucrose Is Sub-Regionally Associated with Striatal Dopamine Transporter in Humans. Neuroendocrinology 2021; 112:338-344. [PMID: 34034262 DOI: 10.1159/000517319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 05/20/2021] [Indexed: 11/19/2022]
Abstract
BACKGROUND Eating behavior is determined by both homeostatic and hedonic values. OBJECTIVE We investigated the association of hedonic value with striatal dopamine transporter (DAT) availability sub-regionally. METHOD An intravenous bolus injection of 18F-FP-CIT was administered after the infusion of glucose or placebo, and the emission data were acquired over 90 min. DAT availability and binding potential (BPND) were measured via the simplified reference tissue method. Subjects were assessed with sensory taste test of sucrose solutions. The "most liked" sucrose concentration (%) was determined as the hedonic rating for sucrose. RESULTS Twenty healthy males participated in this study. After glucose loading, BPNDs of putamen significantly increased, and those of caudate nucleus showed the increasing trend, while those of ventral striatum were not significantly different. After glucose loading, the "most liked" sucrose concentration (%) was negatively associated with BPNDs of caudate nucleus and showed the trend of positive association with those from ventral striatum. Slopes of regression lines were significantly different according to the sub-regions of striatum. CONCLUSION We have highlighted that striatal DAT increased after glucose loading in dorsal striatum, not in ventral striatum. These changes of striatal DAT were sub-regionally associated with the hedonic rating of sucrose from each subject.
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Affiliation(s)
- Kyoungjune Pak
- Department of Nuclear Medicine and Biomedical Research Institute, Pusan National University Hospital and School of Medicine, Pusan National University, Busan, Republic of Korea
| | - Seongho Seo
- Department of Electronic Engineering, Pai Chai University, Daejeon, Republic of Korea
| | - Myung Jun Lee
- Department of Neurology, Pusan National University Hospital, Busan, Republic of Korea
| | - Keunyoung Kim
- Department of Nuclear Medicine and Biomedical Research Institute, Pusan National University Hospital and School of Medicine, Pusan National University, Busan, Republic of Korea
| | - Sunghwan Suh
- Department of Internal Medicine, Dong-A University College of Medicine, Busan, Republic of Korea
| | - Jeehyun Lee
- Department of Food Science and Nutrition, Pusan National University, Busan, Republic of Korea
| | - Seong-Jang Kim
- Department of Nuclear Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea
| | - In Joo Kim
- Department of Nuclear Medicine and Biomedical Research Institute, Pusan National University Hospital and School of Medicine, Pusan National University, Busan, Republic of Korea
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Pak K, Seo S, Kim K, Lee MJ, Shin MJ, Suh S, Im HJ, Park JJ, Kim SJ, Kim IJ. Striatal dopamine transporter changes after glucose loading in humans. Diabetes Obes Metab 2020; 22:116-122. [PMID: 31478329 DOI: 10.1111/dom.13872] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 08/20/2019] [Accepted: 08/28/2019] [Indexed: 12/31/2022]
Abstract
AIMS The dopamine transporter (DAT) actively translocates dopamine that is released from the presynaptic neurons across the membranes of nerve terminals into the extracellular space. We hypothesized that glucose loading-induced changes in striatal DAT levels could be associated with food intake in humans. MATERIALS AND METHODS An intravenous bolus injection of 18 F-FP-CIT was administered after infusion of glucose or placebo (normal saline), and emission data were acquired over 90 minutes in 33 healthy males. For a volume-of-interest-based analysis, an atlas involving sub-striatal regions of ventral striatum (VST), caudate nucleus and putamen was applied. DAT availability and binding potential (BPND ) were measured using a simplified reference tissue method with cerebellum as the reference. RESULTS The glucose-loaded BPND from the VST negatively correlated with body mass index (BMI), whereas the placebo-loaded BPND from the VST did not. After loading with glucose, there were substantial increases in BPND s: 18.3%, 71.7% and 34.0% on average in the VST, caudate nucleus and putamen, respectively. CONCLUSION Striatal DAT changes after glucose loading, and BMI is associated with glucose-loaded DAT availability, not with placebo-loaded DAT availability. DAT might have a role in the reward system of eating behavior.
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Affiliation(s)
- Kyoungjune Pak
- Department of Nuclear Medicine and Biomedical Research Institute, Pusan National University Hospital, Busan, Republic of Korea
| | - Seongho Seo
- Department of Neuroscience, College of Medicine, Gachon University, Incheon, Republic of Korea
- Neuroscience Research Institute, Gachon University, Incheon, Republic of Korea
| | - Keunyoung Kim
- Department of Nuclear Medicine and Biomedical Research Institute, Pusan National University Hospital, Busan, Republic of Korea
| | - Myung Jun Lee
- Department of Neurology, Pusan National University Hospital, Busan, Republic of Korea
| | - Myung Jun Shin
- Department of Rehabilitation Medicine, Pusan National University Hospital, Busan, Republic of Korea
| | - Sunghwan Suh
- Department of Internal Medicine, Dong-A University College of Medicine, Busan, Republic of Korea
| | - Hyung-Jun Im
- Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Republic of Korea
| | - Jung-Jun Park
- Division of Sport Science, Pusan National University, Busan, Republic of Korea
| | - Seong-Jang Kim
- Department of Nuclear Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea
| | - In Joo Kim
- Department of Nuclear Medicine and Biomedical Research Institute, Pusan National University Hospital, Busan, Republic of Korea
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Park SH, Song YS, Moon BS, Lee BC, Park HS, Kim SE. Combination of In Vivo [ 123I]FP-CIT SPECT and Microdialysis Reveals an Antipsychotic Drug Haloperidol-induced Synaptic Dopamine Availability in the Rat Midbrain and Striatum. Exp Neurobiol 2019; 28:602-611. [PMID: 31698552 PMCID: PMC6844836 DOI: 10.5607/en.2019.28.5.602] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 10/25/2019] [Accepted: 10/29/2019] [Indexed: 12/19/2022] Open
Abstract
Synaptic dopamine (DA) is mainly regulated by the presynaptic DA transporter (DAT). Single-photon emission computerized tomography (SPECT) with the DAT radiotracer [123I]FP-CIT assesses changes in synaptic DA availability when endogenous DA displaces [123I]FP-CIT or competes for DAT. Here, we investigated the effects of haloperidol (HAL) and clozapine (CLZ) on [123I]FP-CIT binding in the rat striatum and midbrain to assess the utility of [123I]FP-CIT SPECT to quantify changes in synaptic DA availability. Rats underwent [123I]FP-CIT SPECT after intraperitoneal administration of normal saline (vehicle), HAL (1 and 7 mg/kg), CLZ (10 and 54 mg/kg) and bupropion (BUP, a DAT blocker, 20 and 100 mg/kg). In the striatum and midbrain, percent differences in the nondisplaceable binding potential (BPND) of [123I]FP-CIT compared to the vehicle were calculated for the various drugs and doses. In another experiment, changes in endogenous striatal DA concentration were measured by in vivo microdialysis under the conditions used in the SPECT study. BUP dose-dependently occupied DAT at considerable levels. Compared to the vehicle, HAL decreased [123I]FP-CIT BPND in the striatum (−25.29% and −2.27% for 1 and 7 mg/kg, respectively) and to a greater degree in the midbrain (−58.74% and −49.64% for 1 and 7 mg/kg, respectively), whereas the CLZ-treated group showed a decrease in the midbrain (−38.60% and −40.38% for 10 and 54 mg/kg, respectively) but an increase in the striatum (18.85% and 38.64% for 10 and 54 mg/kg, respectively). Antipsychotic-induced changes in endogenous striatal DA concentrations varied across drugs and doses. The data demonstrate that [123I]FP-CIT SPECT may be a useful preclinical technique for detecting increases in synaptic DA availability in the midbrain and striatum in response to HAL, with results comparable to those of in vivo microdialysis.
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Affiliation(s)
- So Hyeon Park
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Korea
| | - Yoo Sung Song
- Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Byung Seok Moon
- Department of Nuclear Medicine, Ewha Woman's University Seoul Hospital, Ewha Womans University College of Medicine, Seoul 07804, Korea
| | - Byung Chul Lee
- Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Hyun Soo Park
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Korea.,Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Sang Eun Kim
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Korea.,Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seoul 03080, Korea.,Advanced Institutes of Convergence Technology, Suwon 16229, Korea
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Nikolaus S, Antke C, Hautzel H, Mueller HW. Pharmacological treatment with L-DOPA may reduce striatal dopamine transporter binding in in vivo imaging studies. Nuklearmedizin 2015; 55:21-8. [PMID: 26642370 DOI: 10.3413/nukmed-0764-15-08] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 11/20/2015] [Indexed: 11/20/2022]
Abstract
Numerous neurologic and psychiatric conditions are treated with pharmacological compounds, which lead to an increase of synaptic dopamine (DA) levels. One example is the DA precursor L-3,4-dihydroxyphenylalanine (L-DOPA), which is converted to DA in the presynaptic terminal. If the increase of DA concentrations in the synaptic cleft leads to competition with exogenous radioligands for presynaptic binding sites, this may have implications for DA transporter (DAT) imaging studies in patients under DAergic medication. This paper gives an overview on those findings, which, so far, have been obtained on DAT binding in human Parkinson's disease after treatment with L-DOPA. Findings, moreover, are related to results obtained on rats, mice or non-human primates. Results indicate that DAT imaging may be reduced in the striata of healthy animals, in the unlesioned striata of animal models of unilateral Parkinson's disease and in less severly impaired striata of Parkinsonian patients, if animal or human subjects are under acute or subchronic treatment with L-DOPA. If also striatal DAT binding is susceptible to alterations of synaptic DA levels, this may allow to quantify DA reuptake in analogy to DA release by assessing the competition between endogenous DA and the administered exogenous DAT radioligand.
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Affiliation(s)
- S Nikolaus
- Susanne Nikolaus, Clinic of Nuclear Medicine, University Hospital, Moorenstr. 5, 40225 Düsseldorf, Germany, Tel. +49/(0)211/811 70-48, Fax -41,
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Huang C, Ouyang J, Reese TG, Wu Y, El Fakhri G, Ackerman JL. Continuous MR bone density measurement using water- and fat-suppressed projection imaging (WASPI) for PET attenuation correction in PET-MR. Phys Med Biol 2015; 60:N369-81. [PMID: 26405761 PMCID: PMC4607313 DOI: 10.1088/0031-9155/60/20/n369] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Due to the lack of signal from solid bone in normal MR sequences for the purpose of MR-based attenuation correction, investigators have proposed using the ultrashort echo time (UTE) pulse sequence, which yields signal from bone. However, the UTE-based segmentation approach might not fully capture the intra- and inter-subject bone density variation, which will inevitably lead to bias in reconstructed PET images. In this work, we investigated using the water- and fat-suppressed proton projection imaging (WASPI) sequence to obtain accurate and continuous attenuation for bones. This approach is capable of accounting for intra- and inter-subject bone attenuation variations. Using data acquired from a phantom, we have found that that attenuation correction based on the WASPI sequence is more accurate and precise when compared to either conventional MR attenuation correction or UTE-based segmentation approaches.
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Affiliation(s)
- C Huang
- Center for Advanced Medical Imaging Sciences, Department of Imaging, Massachusetts General Hospital, Boston, MA 02114, USA. Department of Radiology, Harvard Medical School, Boston, MA 02115, USA. Departments of Radiology, Psychiatry, Stony Brook Medicine, Stony Brook, NY 11794, USA
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Bakker G, Vingerhoets WA, Wieringen JV, de Bruin K, Eersels J, de Jong J, Chahid Y, Rutten BP, DuBois S, Watson M, Mogg AJ, Xiao H, Crabtree M, Collier DA, Felder CC, Barth VN, Broad LM, Bloemen OJ, van Amelsvoort TA, Booij J. 123I-Iododexetimide Preferentially Binds to the Muscarinic Receptor Subtype M1 In Vivo. J Nucl Med 2015; 56:317-22. [DOI: 10.2967/jnumed.114.147488] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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