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Yamasaki T, Ishii H, Hiraishi A, Kumata K, Wakizaka H, Zhang Y, Kurihara Y, Ogawa M, Nengaki N, Chen J, Li Y, Liang S, Zhang MR. Small-animal PET study for noninvasive quantification of transmembrane AMPA receptor regulatory protein γ-8 (TARP γ-8) in the brain. J Cereb Blood Flow Metab 2023; 43:893-904. [PMID: 36655318 DOI: 10.1177/0271678x231152025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Transmembrane AMPA receptor regulatory protein γ-8 (TARP γ-8) mediates various AMPA receptor functions. Recently, [11C]TARP-2105 was developed as a PET ligand for TARP γ-8 imaging. We performed a full kinetic analysis of [11C]TARP-2105 using PET with [11C]TARP-2105 for the first time. The distribution volume (VT), which is a macro parameter consisting of the K1-k4 rate constants in the two-tissue compartment model analysis, exhibited the following rank order: hippocampus (1.4 ± 0.3) > amygdala (1.0 ± 0.2) > frontal cortex (0.9 ± 0.2) > striatum (0.8 ± 0.2) ≫ cerebellum (0.5 ± 0.1) ≈ thalamus (0.5 ± 0.1) > pons (0.4 ± 0.1 mL/cm3). These heterogenous VT values corresponded with the order of biological distribution of TARP γ-8 in the brain. To validate the reference tissue model, the binding potential (BPND) of [11C]TARP-2105 for TARP γ-8 was estimated using general methods (SRTM, MRTM0, Logan reference model, and ratio method). These BPNDs based on reference models indicated excellent correlation (R2 > 0.9) to the indirect BPNDs based on 2TCM with moderate reproducibility (%variability ≈ 10). PET with [11C]TARP-2105 enabled noninvasive BPND estimation and visual mapping of TARP γ-8 in the living rat brain.
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Affiliation(s)
- Tomoteru Yamasaki
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, Chiba, Japan
| | - Hideki Ishii
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, Chiba, Japan
| | - Atsuto Hiraishi
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, Chiba, Japan
| | - Katsushi Kumata
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, Chiba, Japan
| | - Hidekatsu Wakizaka
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, Chiba, Japan
| | - Yiding Zhang
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, Chiba, Japan
| | - Yusuke Kurihara
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, Chiba, Japan.,SHI Accelerator Service Ltd., Tokyo, Japan
| | - Masanao Ogawa
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, Chiba, Japan.,SHI Accelerator Service Ltd., Tokyo, Japan
| | - Nobuki Nengaki
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, Chiba, Japan.,SHI Accelerator Service Ltd., Tokyo, Japan
| | - Jiahui Chen
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital and Department of Radiology, Harvard Medical School, Boston, MA, USA.,Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, USA
| | - Yinlong Li
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital and Department of Radiology, Harvard Medical School, Boston, MA, USA.,Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, USA
| | - Steven Liang
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital and Department of Radiology, Harvard Medical School, Boston, MA, USA.,Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, USA
| | - Ming-Rong Zhang
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, Chiba, Japan
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Yamasaki T, Kumata K, Hiraishi A, Zhang Y, Wakizaka H, Kurihara Y, Nengaki N, Zhang MR. Synthesis of [ 11C]carbonyl-labeled cyclohexyl (5-(2-acetamidobenzo[d]thiazol-6-yl)-2-methylpyridin-3-yl)carbamate ([ 11C-carbonyl]PK68) as a potential PET tracer for receptor-interacting protein 1 kinase. EJNMMI Radiopharm Chem 2022; 7:4. [PMID: 35290562 PMCID: PMC8924334 DOI: 10.1186/s41181-022-00156-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 03/02/2022] [Indexed: 11/28/2022] Open
Abstract
Background Receptor-interacting protein 1 kinase (RIPK1) is a key enzyme in the regulation of cellular necroptosis. Recently, cyclohexyl (5-(2-acetamidobenzo[d]thiazol-6-yl)-2-methylpyridin-3-yl)carbamate (PK68, 5) has been developed as a potent inhibitor of RIPK1. Herein, we synthesized [11C]carbonyl-labeled PK68 ([11C-carbonyl]PK68, [11C]PK68) as a potential PET tracer for imaging RIPK1 and evaluated its brain uptake in vivo. Results We synthesized [11C]PK68 by reacting amine precursor 14 with [11C]acetyl chloride. At the end of synthesis, we obtained [11C]PK68 of 1200–1790 MBq with a radiochemical yield of 9.1 ± 5.9% (n = 10, decay-corrected to the end of irradiation) and radiochemical purity of > 99%, and a molar activity of 37–99 GBq/μmol starting from 18–33 GBq of [11C]CO2. The fully automated synthesis took 30 min from the end of irradiation. In a small-animal PET study, [11C]PK68 was rapidly distributed in the liver and kidneys of healthy mice after injection, and subsequently cleared from their bodies via hepatobiliary excretion and the intestinal reuptake pathway. Although there was no obvious specific binding of RIPK1 in the PET study, [11C]PK68 demonstrated relatively high stability in vivo and provided useful structural information further candidate development. Conclusions In the present study, we successfully radiosynthesized [11C]PK68 as a potential PET tracer and evaluated its brain uptake. We are planning to optimize the chemical structure of [11C]PK68 and conduct further PET studies on it using pathological models.
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Affiliation(s)
- Tomoteru Yamasaki
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Katsushi Kumata
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Atsuto Hiraishi
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Yiding Zhang
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Hidekatsu Wakizaka
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Yusuke Kurihara
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.,SHI Accelerator Service Co. Ltd., 1-17-6 Osaki, Shinagawa-ku, Tokyo, 141-0032, Japan
| | - Nobuki Nengaki
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.,SHI Accelerator Service Co. Ltd., 1-17-6 Osaki, Shinagawa-ku, Tokyo, 141-0032, Japan
| | - Ming-Rong Zhang
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.
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D'Elia A, Schiavi S, Soluri A, Massari R, Soluri A, Trezza V. Role of Nuclear Imaging to Understand the Neural Substrates of Brain Disorders in Laboratory Animals: Current Status and Future Prospects. Front Behav Neurosci 2020; 14:596509. [PMID: 33362486 PMCID: PMC7759612 DOI: 10.3389/fnbeh.2020.596509] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 11/23/2020] [Indexed: 12/18/2022] Open
Abstract
Molecular imaging, which allows the real-time visualization, characterization and measurement of biological processes, is becoming increasingly used in neuroscience research. Scintigraphy techniques such as single photon emission computed tomography (SPECT) and positron emission tomography (PET) provide qualitative and quantitative measurement of brain activity in both physiological and pathological states. Laboratory animals, and rodents in particular, are essential in neuroscience research, providing plenty of models of brain disorders. The development of innovative high-resolution small animal imaging systems together with their radiotracers pave the way to the study of brain functioning and neurotransmitter release during behavioral tasks in rodents. The assessment of local changes in the release of neurotransmitters associated with the performance of a given behavioral task is a turning point for the development of new potential drugs for psychiatric and neurological disorders. This review addresses the role of SPECT and PET small animal imaging systems for a better understanding of brain functioning in health and disease states. Brain imaging in rodent models faces a series of challenges since it acts within the boundaries of current imaging in terms of sensitivity and spatial resolution. Several topics are discussed, including technical considerations regarding the strengths and weaknesses of both technologies. Moreover, the application of some of the radioligands developed for small animal nuclear imaging studies is discussed. Then, we examine the changes in metabolic and neurotransmitter activity in various brain areas during task-induced neural activation with special regard to the imaging of opioid, dopaminergic and cannabinoid receptors. Finally, we discuss the current status providing future perspectives on the most innovative imaging techniques in small laboratory animals. The challenges and solutions discussed here might be useful to better understand brain functioning allowing the translation of preclinical results into clinical applications.
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Affiliation(s)
- Annunziata D'Elia
- Institute of Biochemistry and Cell Biology, National Research Council of Italy (CNR), Rome, Italy.,Section of Biomedical Sciences and Technologies, Department of Science, University "Roma Tre", Rome, Italy
| | - Sara Schiavi
- Section of Biomedical Sciences and Technologies, Department of Science, University "Roma Tre", Rome, Italy
| | - Andrea Soluri
- Institute of Biochemistry and Cell Biology, National Research Council of Italy (CNR), Rome, Italy
| | - Roberto Massari
- Institute of Biochemistry and Cell Biology, National Research Council of Italy (CNR), Rome, Italy
| | - Alessandro Soluri
- Institute of Biochemistry and Cell Biology, National Research Council of Italy (CNR), Rome, Italy
| | - Viviana Trezza
- Section of Biomedical Sciences and Technologies, Department of Science, University "Roma Tre", Rome, Italy
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Yamasaki T, Ohya T, Mori W, Zhang Y, Wakizaka H, Nengaki N, Fujinaga M, Kikuchi T, Zhang MR. Development of an In Vivo Method to Estimate Effective Drug Doses and Quantify Fatty Acid Amide Hydrolase in Rodent Brain using Positron Emission Tomography Tracer [ 11C]DFMC. J Pharmacol Exp Ther 2020; 373:353-360. [PMID: 32241809 DOI: 10.1124/jpet.119.263772] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 03/27/2020] [Indexed: 11/22/2022] Open
Abstract
Fatty acid amide hydrolase (FAAH) is a key enzyme in the endocannabinoid system. N-(3,4-Dimethylisoxazol-5-yl)piperazine-4-[4-(2-fluoro-4-[11C]methylphenyl)thiazol-2-yl]-1-carboxamide ([11C]DFMC) was developed as an irreversible-type positron emission tomography (PET) tracer for FAAH. Here, we attempted to noninvasively estimate rate constant k3 (rate of transfer to the specifically-bound compartment) as a direct index for FAAH in the rat brain. First, the two-tissue compartment model analysis including three parameters [K1-k3, two-tissue compartment model for the irreversible-type radiotracer (2TCMi)] in PET study with [11C]DFMC was conducted, which provided 0.21 ± 0.04 ml·cm-3·min-1 of the net uptake value (Ki), an indirect index for FAAH, in the FAAH-richest region (the cingulate cortex). Subsequently, to noninvasively estimate Ki value, the reference model analysis (Patlak graphical analysis reference model) was tried using a time-activity curve of the spinal cord. In that result, the noninvasive Ki value (KREF) was concisely estimated with high correlation (r > 0.95) to Ki values based on 2TCMi. Using estimated KREF value, we tried to obtain calculated-k3 based on previously defined equations. The calculated k3 was successfully estimated with high correlation (r = 0.95) to direct k3 in 2TCMi. Finally, the dose relationship study using calculated k3 demonstrated that in vivo ED50 value of [3-(3-carbamoylphenyl)phenyl] N-cyclohexylcarbamate, a major inhibitor of FAAH, was 66.4 µg/kg in rat brain. In conclusion, we proposed the calculated k3 as an alternative index corresponding to regional FAAH concentrations and suggested that PET with [11C]DFMC enables occupancy study for new pharmaceuticals targeting FAAH. SIGNIFICANCE STATEMENT: In the present study, we proposed calculated k3 as an alternative index corresponding with fatty acid amide hydrolase concentration. By using calculated k3, in vivo ED50 of [3-(3-carbamoylphenyl)phenyl] N-cyclohexylcarbamate was successfully estimated to be 66.4 µg/kg for rats. Thus, we demonstrated the pharmacological utility of positron emission tomography with N-(3,4-dimethylisoxazol-5-yl)piperazine-4-[4-(2-fluoro-4-[11C]methylphenyl)thiazol-2-yl]-1-carboxamide.
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Affiliation(s)
- Tomoteru Yamasaki
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Tomoyuki Ohya
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Wakana Mori
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Yiding Zhang
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Hidekatsu Wakizaka
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Nobuki Nengaki
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Masayuki Fujinaga
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Tatsuya Kikuchi
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Ming-Rong Zhang
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
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Evaluation of drug effects on cerebral blood flow and glucose uptake in un-anesthetized and un-stimulated rats: application of free-moving apparatus enabling to keep rats free during PET/SPECT tracer injection and uptake. Nucl Med Commun 2018; 39:753-760. [PMID: 29771718 PMCID: PMC6075887 DOI: 10.1097/mnm.0000000000000863] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Objectives The purpose of this study is the development of novel fluorine-18-fluorodeoxyglucose (18F-FDG)-PET and 99mTc-hexamethylpropylene amine oxime (HMPAO) SPECT methods with free-moving apparatus on conscious rats to investigate brain activity without the effects of anesthesia and tactual stimulation. We also assessed the sensitivity of the experimental system by an intervention study using fluoxetine as a reference drug. Materials and methods A catheter was inserted into the femoral vein and connected to a free-moving cannula system. After fluoxetine administration, the rats were given an injection of 18F-FDG or 99mTc-HMPAO via the intravenous cannula and released into a free-moving cage. After the tracer was trapped in the brain, the rats were anesthetized and scanned with PET or SPECT scanners. Then a volume of interest analysis and statistical parametric mapping were performed. Results We could inject the tracer without touching the rats, while keeping them conscious until the tracers were distributed and trapped in the brain using the developed system. The effects of fluoxetine on glucose uptake and cerebral blood flow were perceptively detected by volume of interest and statistical parametric mapping analysis. Conclusion We successfully developed free-moving 18F-FDG-PET and 99mTc-HMPAO-SPECT imaging systems and detected detailed glucose uptake and cerebral blood flow changes in the conscious rat brain with fluoxetine administration. This system is expected to be useful to assess brain activity without the effects of anesthesia and tactual stimulation to evaluate drug effect or animal brain function.
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Modeling of PET data in CNS drug discovery and development. J Pharmacokinet Pharmacodyn 2013; 40:267-79. [PMID: 23660778 DOI: 10.1007/s10928-013-9320-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 04/26/2013] [Indexed: 12/22/2022]
Abstract
Positron emission tomography (PET) is increasingly used in drug discovery and development for evaluation of CNS drug disposition and for studies of disease biomarkers to monitor drug effects on brain pathology. The quantitative analysis of PET data is based on kinetic modeling of radioactivity concentrations in plasma and brain tissue compartments. A number of quantitative methods of analysis have been developed that allow the determination of parameters describing drug pharmacokinetics and interaction with target binding sites in the brain. The optimal method of quantification depends on the properties of the radiolabeled drug or radioligand and the binding site studied. We here review the most frequently used methods for quantification of PET data in relation to CNS drug discovery and development. The utility of PET kinetic modeling in the development of novel CNS drugs is illustrated by examples from studies of the brain kinetic properties of radiolabeled drug molecules.
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Evaluation of dopamine D₂/D₃ and serotonin 5-HT₂A receptor occupancy for a novel antipsychotic, lurasidone, in conscious common marmosets using small-animal positron emission tomography. Psychopharmacology (Berl) 2013; 225:329-39. [PMID: 22868411 DOI: 10.1007/s00213-012-2815-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 07/17/2012] [Indexed: 12/13/2022]
Abstract
RATIONALE Lurasidone is a novel antipsychotic drug with potent binding affinity for dopamine D(2) and serotonin (5-hydroxytryptamine, 5-HT)(2A), 5-HT(7), and 5-HT(1A) receptors. Previous pharmacological studies have revealed that lurasidone exhibits a preferable profile (potent antipsychotic activity and lower incidence of catalepsy) to other antipsychotic drugs, although the contribution of receptor subtypes to this profile remains unclear. OBJECTIVES To compare target engagements of lurasidone with those of an atypical antipsychotic, olanzapine, we performed evaluation of dopamine D(2)/D(3) and serotonin 5-HT(2A) receptor occupancy in vivo by positron emission tomography (PET) with conscious common marmosets. METHODS We measured brain receptor occupancies in conscious common marmosets after oral administrations of lurasidone or olanzapine by PET with [(11)C]raclopride and [(11)C]R-(+)-α-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenylethyl)]-4-piperidine methanol (MDL 100907) for D(2)/D(3) and 5-HT(2A) receptors, respectively. RESULTS Increases in brain D(2)/D(3) receptor occupancies of both lurasidone and olanzapine, which reached >80 % at maximum, were observed in the striatum with significant correlations to plasma drug levels. However, lurasidone showed lower 5-HT(2A) receptor occupancy in the frontal cortex within the same dose range, while olanzapine showed broadly comparable 5-HT(2A) and D(2)/D(3) receptor occupancies. CONCLUSIONS Compared with olanzapine, lurasidone preferentially binds to D(2)/D(3) receptors rather than 5-HT(2A) receptors in common marmosets. These results suggest that the contribution of in vivo 5-HT(2A) receptor blocking activity to the pharmacological profile of lurasidone might differ from olanzapine in terms of the low risk of extrapyramidal syndrome and efficacy against negative symptoms.
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Yamasaki T, Fujinaga M, Kawamura K, Yui J, Hatori A, Ohya T, Xie L, Wakizaka H, Yoshida Y, Fukumura T, Zhang MR. In Vivo Measurement of the Affinity and Density of Metabotropic Glutamate Receptor Subtype 1 in Rat Brain Using 18F-FITM in Small-Animal PET. J Nucl Med 2012; 53:1601-7. [DOI: 10.2967/jnumed.112.105908] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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Saijo T, Maeda J, Okauchi T, Maeda JI, Morio Y, Kuwahara Y, Suzuki M, Goto N, Fukumura T, Suhara T, Higuchi M. Presynaptic selectivity of a ligand for serotonin 1A receptors revealed by in vivo PET assays of rat brain. PLoS One 2012; 7:e42589. [PMID: 22880045 PMCID: PMC3413639 DOI: 10.1371/journal.pone.0042589] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 07/10/2012] [Indexed: 11/19/2022] Open
Abstract
A novel investigational antidepressant with high affinity for the serotonin transporter and the serotonin 1A (5-HT(1A)) receptor, called Wf-516 (structural formula: (2S)-1-[4-(3,4-dichlorophenyl)piperidin-1-yl]-3-[2-(5-methyl-1,3,4-oxadiazol-2-yl)benzo[b]furan-4-yloxy]propan-2-ol monohydrochloride), has been found to exert a rapid therapeutic effect, although the mechanistic basis for this potential advantage remains undetermined. We comparatively investigated the pharmacokinetics and pharmacodynamics of Wf-516 and pindolol by positron emission tomographic (PET) and autoradiographic assays of rat brains in order to elucidate their molecular interactions with presynaptic and postsynaptic 5-HT(1A) receptors. In contrast to the full receptor occupancy by pindolol in PET measurements, the binding of Wf-516 to 5-HT(1A) receptors displayed limited capacity, with relatively high receptor occupancy being achieved in regions predominantly containing presynaptic receptors. This selectivity was further proven by PET scans of neurotoxicant-treated rats deficient in presynaptic 5-HT(1A) receptors. In addition, [(35)S]guanosine 5'-O-[γ-thio]triphosphate autoradiography indicated a partial agonistic ability of Wf-516 for 5-HT(1A) receptors. This finding has lent support to reports that diverse partial agonists for 5-HT(1A) receptors exert high sensitivity for presynaptic components. Thus, the present PET data suggest a relatively high capacity of presynaptic binding sites for partial agonists. Since our in vitro and ex vivo autoradiographies failed to illustrate these distinct features of Wf-516, in vivo PET imaging is considered to be, thus far, the sole method capable of pharmacokinetically demonstrating the unique actions of Wf-516 and similar new-generation antidepressants.
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Affiliation(s)
- Takeaki Saijo
- Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
- Department of Molecular Neuroimaging, Tohoku University School of Medicine, Sendai, Japan
- DMPK Research Laboratory, Mitsubishi Tanabe Pharma Corporation, Kisarazu, Japan
| | - Jun Maeda
- Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Takashi Okauchi
- Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Jun-ichi Maeda
- Research Quality Assurance Department, Mitsubishi Tanabe Pharma Corporation, Yokohama, Japan
| | - Yasunori Morio
- Development Project Management Department, Mitsubishi Tanabe Pharma Corporation, Tokyo, Japan
| | - Yasuhiro Kuwahara
- Advanced Medical Research Laboratory, Mitsubishi Tanabe Pharma Corporation, Yokohama, Japan
| | - Masayuki Suzuki
- DMPK Research Laboratory, Mitsubishi Tanabe Pharma Corporation, Kisarazu, Japan
| | - Nobuharu Goto
- Early Stage Clinical Research Center, Mitsubishi Tanabe Pharma Corporation, Tokyo, Japan
| | - Toshimitsu Fukumura
- Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Tetsuya Suhara
- Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
- Department of Molecular Neuroimaging, Tohoku University School of Medicine, Sendai, Japan
| | - Makoto Higuchi
- Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
- Department of Molecular Neuroimaging, Tohoku University School of Medicine, Sendai, Japan
- * E-mail:
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Translational CNS medicines research. Drug Discov Today 2012; 17:1068-78. [PMID: 22580061 DOI: 10.1016/j.drudis.2012.05.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 03/22/2012] [Accepted: 05/02/2012] [Indexed: 12/31/2022]
Abstract
The major imperative of the pharmaceutical industry is to effectively translate insights gained from basic research into new medicines. This task is toughest for CNS disorders. Compared with non-CNS drugs, CNS drugs take longer to get to market and their attrition rate is greater. This is principally because of the complexity of the human brain (the cause of many brain disorders remains unknown), the liability of CNS drugs to cause CNS side effects (which limits their use) and the requirement of CNS medicines to cross the blood-CNS barrier (BCNSB) (which restricts their ability to interact with their CNS target). In this review we consider the factors that are important in translating neuroscience research into CNS medicines.
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Higuchi M, Maeda J, Ji B, Tokunaga M, Zhang MR, Maruyama M, Ono M, Fukumura T, Suhara T. PET applications in animal models of neurodegenerative and neuroinflammatory disorders. Curr Top Behav Neurosci 2012; 11:45-64. [PMID: 22016108 DOI: 10.1007/7854_2011_167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Studies on hereditary neurological disorders such as familial Alzheimer's disease (AD) have revealed abnormalities of pathogenic proteins causative of neurodegeneration, while molecular initiators of sporadic neuropsychiatric conditions remain unidentified. Such disorders are characterized by collections of molecular abnormalities that may be critically involved in synaptic dysfunctions and other deteriorations in neurons. Diverse classes of radiochemicals designed for positron emission tomographic (PET) imaging facilitate delineation of mechanistic links among key molecules in these processes by tracking their spatiotemporal correlations. This assay technique is of particular utility when applied to rodent and nonhuman primate models given their suitability for invasive genetic and pharmacological interventions. In addition, the detection of neurochemical and neuropathological changes by PET can be examined in laboratory animals when combined with invasive antemortem and postmortem investigations such as in vivo microdialysis, electrophysiological and histopathological techniques. This review primarily covers the use of small animal models of brain disorders using PET to elucidate etiological molecular cascades to facilitate in turn the search for diagnostic and therapeutic agents applicable to AD and related disorders in humans.
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Affiliation(s)
- Makoto Higuchi
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan,
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Sekine M, Maeda J, Shimada H, Nogami T, Arakawa R, Takano H, Higuchi M, Ito H, Okubo Y, Suhara T. Central nervous system drug evaluation using positron emission tomography. CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE 2011; 9:9-16. [PMID: 23431048 PMCID: PMC3568655 DOI: 10.9758/cpn.2011.9.1.9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2010] [Revised: 01/18/2011] [Accepted: 01/19/2011] [Indexed: 12/20/2022]
Abstract
In conventional pharmacological research in the field of mental disorders, pharmacological effect and dose have been estimated by ethological approach and in vitro data of affinity to the site of action. In addition, the frequency of administration has been estimated from drug kinetics in blood. However, there is a problem regarding an objective index of drug effects in the living body. Furthermore, the possibility that the concentration of drug in blood does not necessarily reflect the drug kinetics in target organs has been pointed out. Positron emission tomography (PET) techniques have made progress for more than 20 years, and made it possible to measure the distribution and kinetics of small molecule components in living brain. In this article, we focused on rational drug dosing using receptor occupancy and proof-of-concept of drugs in the drug development process using PET.
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Affiliation(s)
- Mizuho Sekine
- Molecular Neuroimaging Group, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan. ; Department of Neuropsychiatry, Nippon Medical School, Tokyo, Japan
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Xi W, Tian M, Zhang H. Molecular imaging in neuroscience research with small-animal PET in rodents. Neurosci Res 2011; 70:133-43. [PMID: 21241748 DOI: 10.1016/j.neures.2010.12.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 12/21/2010] [Accepted: 12/24/2010] [Indexed: 10/18/2022]
Abstract
Cognitive neuroscience, which studies the biological basis of mental processes, widely uses neuroimaging technologies like functional magnetic resonance imaging and positron emission tomography (PET) to study the human brain. Small laboratory animals, like rodents, are commonly used in brain research and provide abundant models of human brain diseases. The development of high-resolution small-animal PET and various radiotracers together with sophisticated methods for analyzing functional brain imaging data have accelerated research on brain function and neurotransmitter release during behavioral tasks in rodents. In this review, we first summarize advances in the methodology of cognitive research brought about by the development of sophisticated methods for whole-brain imaging analysis and improvements in neuroimaging protocols. Then, we discuss basic mechanisms related to metabolic changes and the expression of neurotransmitters in various brain areas during task-induced neural activity. In particular, we discuss glucose metabolism imaging and brain receptor imaging for various receptor systems. Finally, we discuss the current status and future perspectives. Mechanisms of neurotransmitter expression will probably become an increasingly important field of study in the future, leading to more collaboration between investigators in fields such as computational and theoretical neuroscience.
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Affiliation(s)
- Wang Xi
- Department of Nuclear Medicine, Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, China
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