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Moon SH, El Fakhri G, Zhang Z, Brownell AL, Wang J. Fully Automated Radiosynthesis of [ 18F]mG4P027 for mGluR4 Imaging. IRADIOLOGY 2023; 1:120-127. [PMID: 37496513 PMCID: PMC10371389 DOI: 10.1002/ird3.25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Accepted: 05/18/2023] [Indexed: 07/28/2023]
Abstract
Fluorine-18 labeled N-(4-chloro-3-(((fluoro-18F)methyl-d2)thio)phenyl)picolinamide, [18F]mG4P027, is a potent positron emission tomography (PET) radiotracer for metabotropic glutamate receptor 4 (mGluR4). Our previous in vitro and in vivo evaluations have demonstrated that this tracer is promising for further translational studies. To automate the radiosynthesis of [18F]mG4P027, significant modifications were made to the manual process by carefully examining this process and addressing the root causes of the challenges associated with its automation. We successfully implemented its automated radiosynthesis using the TRACERlab FX2N module and consequently, obtained a high-purity radiolabeled [18F]mG4P027 in high yield, meeting the requirements for future human studies.
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Affiliation(s)
- Sung-Hyun Moon
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114 (USA)
| | - Georges El Fakhri
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114 (USA)
| | - Zhaoda Zhang
- Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114 (USA)
| | - Anna-Liisa Brownell
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114 (USA)
| | - Junfeng Wang
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114 (USA)
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Wang J, Moon SH, Cleary MB, Shoup TM, El Fakhri G, Zhang Z, Brownell AL. Detailed radiosynthesis of [ 18 F]mG4P027 as a positron emission tomography radiotracer for mGluR4. J Labelled Comp Radiopharm 2023; 66:34-40. [PMID: 36593743 PMCID: PMC9985952 DOI: 10.1002/jlcr.4011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/25/2022] [Accepted: 12/29/2022] [Indexed: 01/04/2023]
Abstract
We report here the detailed radiosynthesis of [18 F]mG4P027, a metabotropic glutamate receptor 4 (mGluR4) PET radiotracer, which showed superior properties to the currently reported mGluR4 radiotracers. The radiosynthesis in the automated system has been challenging, therefore we disclose here the major limiting factors for the synthesis via step-by-step examination. And we hope this thorough study will help its automation for human use in the future.
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Affiliation(s)
| | | | - Michael B. Cleary
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA 02114 (USA)
| | | | | | - Zhaoda Zhang
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA 02114 (USA)
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Bian Y, Jun JJ, Cuyler J, Xie XQ. Covalent allosteric modulation: An emerging strategy for GPCRs drug discovery. Eur J Med Chem 2020; 206:112690. [PMID: 32818870 PMCID: PMC9948676 DOI: 10.1016/j.ejmech.2020.112690] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/10/2020] [Accepted: 07/24/2020] [Indexed: 12/13/2022]
Abstract
Designing covalent allosteric modulators brings new opportunities to the field of drug discovery towards G-protein-coupled receptors (GPCRs). Targeting an allosteric binding pocket can allow a modulator to have protein subtype selectivity and low drug resistance. Utilizing covalent warheads further enables the modulator to increase the binding potency and extend the duration of action. This review starts with GPCR allosteric modulation to discuss the structural biology of allosteric binding pockets, the different types of allosteric modulators, as well as the advantages of employing allosteric modulation. This is followed by a discussion on covalent modulators to clarify how covalent ligands can benefit the receptor modulation and to illustrate moieties that can commonly be used as covalent warheads. Finally, case studies are presented on designing class A, B, and C GPCR covalent allosteric modulators to demonstrate successful stories on combining allosteric modulation and covalent binding. Limitations and future perspectives are also covered.
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Affiliation(s)
- Yuemin Bian
- Department of Pharmaceutical Sciences and Computational Chemical Genomics Screening Center, School of Pharmacy,NIH National Center of Excellence for Computational Drug Abuse Research
| | - Jaden Jungho Jun
- Department of Pharmaceutical Sciences and Computational Chemical Genomics Screening Center, School of Pharmacy,NIH National Center of Excellence for Computational Drug Abuse Research
| | - Jacob Cuyler
- Department of Pharmaceutical Sciences and Computational Chemical Genomics Screening Center, School of Pharmacy,NIH National Center of Excellence for Computational Drug Abuse Research
| | - Xiang-Qun Xie
- Department of Pharmaceutical Sciences and Computational Chemical Genomics Screening Center, School of Pharmacy, Pittsburgh, PA, 15261, United States; NIH National Center of Excellence for Computational Drug Abuse Research, Pittsburgh, PA, 15261, United States; Drug Discovery Institute, Pittsburgh, PA, 15261, United States; Departments of Computational Biology and Structural Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15261, United States.
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Doller D, Bespalov A, Miller R, Pietraszek M, Kalinichev M. A case study of foliglurax, the first clinical mGluR4 PAM for symptomatic treatment of Parkinson's disease: translational gaps or a failing industry innovation model? Expert Opin Investig Drugs 2020; 29:1323-1338. [PMID: 33074728 DOI: 10.1080/13543784.2020.1839047] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
INTRODUCTION Approximately 40% of Parkinson's disease (PD) patients that take mostly dopamine receptor agonists for motor fluctuations, experience the return of symptoms between regular doses. This is a phenomenon known as 'OFF periods.' Positive allosteric modulators (PAMs) of metabotropic glutamate receptor 4 (mGluR4) are a promising non-dopaminergic mechanism with potential to address the unmet need of patients suffering from OFF periods. Foliglurax is the first mGluR4 PAM that has advanced into clinical testing in PD patients. AREAS COVERED We summarize the chemistry, pharmacokinetics, and preclinical pharmacology of foliglurax. Translational PET imaging studies, clinical efficacy data, and a competitive landscape analysis of available therapies are presented to the readers. In this Perspective article, foliglurax is used as a case study to illustrate the inherent R&D challenges that companies face when developing drugs. These challenges include the delivery of drugs acting through novel mechanisms, long-term scientific investment, and commercial success and shorter-term positive financial returns. EXPERT OPINION Failure to meet the primary and secondary endpoints in a Phase 2 study led Lundbeck to discontinue the development of foliglurax. Understanding the evidence supporting compound progression into Phase 2 will enable the proper assessment of the therapeutic potential of mGluR4 PAMs.
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Affiliation(s)
| | - Anton Bespalov
- Partnership for Assessment and Accreditation of Scientific Practice , Heidelberg, Germany.,Valdman Institute of Pharmacology, Pavlov Medical University , St. Petersburg, Russia
| | - Rob Miller
- Ventral Stream Consulting LLC ., IL, USA
| | - Malgorzata Pietraszek
- Partnership for Assessment and Accreditation of Scientific Practice , Heidelberg, Germany
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Wang J, Qu X, Shoup TM, Yuan G, Afshar S, Pan C, Zhu A, Choi JK, Kang HJ, Poutiainen P, ElFakhri G, Zhang Z, Brownell AL. Synthesis and Characterization of Fluorine-18-Labeled N-(4-Chloro-3-((fluoromethyl- d2)thio)phenyl)picolinamide for Imaging of mGluR4 in Brain. J Med Chem 2020; 63:3381-3389. [PMID: 32081008 PMCID: PMC7261135 DOI: 10.1021/acs.jmedchem.0c00201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We have synthesized and characterized [18F]-N-(4-chloro-3-((fluoromethyl-d2)thio)phenyl)-picolinamide ([18F]15) as a potential ligand for the positron emission tomography (PET) imaging of mGluR4 in the brain. Radioligand [18F]15 displays central nervous system drug-like properties, including mGluR4 affinity, potent mGluR4 PAM activity, and selectivity against other mGluRs, as well as sufficient metabolic stability. Radiosynthesis was carried out in two steps. The radiochemical yield of [18F]15 was 11.6 ± 2.9% (n = 7, decay corrected) with a purity of 99% and a molar activity of 84.1 ± 11.8 GBq/μmol. Ex vivo biodistribution studies showed reversible binding of [18F]15 in all investigated tissues including the brain, liver, heart, lungs, and kidneys. PET imaging studies in male Sprague Dawley rats showed that [18F]15 accumulates in the brain regions known to express mGluR4. Pretreatment with the unlabeled mGluR4 PAM compounds 13 (methylthio analogue) and 15 showed significant dose-dependent blocking effects. These results suggest that [18F]15 is a promising radioligand for PET imaging mGluR4 in the brain.
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Affiliation(s)
- Junfeng Wang
- Gordon Center for Medical Imaging, Massachusetts General Hospital and Harvard Medical School, 125 Nashua Street, Suite 660, Boston, MA 02114
| | - Xiying Qu
- Gordon Center for Medical Imaging, Massachusetts General Hospital and Harvard Medical School, 125 Nashua Street, Suite 660, Boston, MA 02114
| | - Timothy M. Shoup
- Gordon Center for Medical Imaging, Massachusetts General Hospital and Harvard Medical School, 125 Nashua Street, Suite 660, Boston, MA 02114
| | - Gengyang Yuan
- Gordon Center for Medical Imaging, Massachusetts General Hospital and Harvard Medical School, 125 Nashua Street, Suite 660, Boston, MA 02114
| | - Sepideh Afshar
- Gordon Center for Medical Imaging, Massachusetts General Hospital and Harvard Medical School, 125 Nashua Street, Suite 660, Boston, MA 02114
| | - Chuzhi Pan
- Gordon Center for Medical Imaging, Massachusetts General Hospital and Harvard Medical School, 125 Nashua Street, Suite 660, Boston, MA 02114
- The Third Affiliated Hospital of Sun Yat-sen University, 510630, China
| | - Aijun Zhu
- Gordon Center for Medical Imaging, Massachusetts General Hospital and Harvard Medical School, 125 Nashua Street, Suite 660, Boston, MA 02114
| | - Ji-Kyung Choi
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, 149 Thirteenth Street, Suite 2301 Charlestown, MA 02129
| | - Hye Jin Kang
- Department of Pharmacology, University of North Carolina Chapel Hill School of Medicine, Chapel Hill, North Carolina 27514, United States
| | | | - Georges ElFakhri
- Gordon Center for Medical Imaging, Massachusetts General Hospital and Harvard Medical School, 125 Nashua Street, Suite 660, Boston, MA 02114
| | - Zhaoda Zhang
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, 149 Thirteenth Street, Suite 2301 Charlestown, MA 02129
| | - Anna-Liisa Brownell
- Gordon Center for Medical Imaging, Massachusetts General Hospital and Harvard Medical School, 125 Nashua Street, Suite 660, Boston, MA 02114
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Wang J, Shoup TM, Brownell AL, Zhang Z. Improved Synthesis of the Thiophenol Precursor N-(4-Chloro-3-mercaptophenyl)picolinamide for Making the mGluR4 PET Ligand. Tetrahedron 2019; 75:3917-3922. [PMID: 32831413 PMCID: PMC7442123 DOI: 10.1016/j.tet.2019.06.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Recently [11C]mG4P012 (previously [11C]KALB012 and presently named as [11C]PXT012253 by Prexton Therapeutics) had been used as a biomarker during the preclinical development of a potential therapeutic drug, PXT0002331 (an mGluR4 PAM), for PD and L-dopa-induced dyskinesia. [11C]mG4P012 was shown to be a promising PET radioligand for mGluR4 in the monkey brain and for further development in human subjects. However, the previously reported multi-step synthesis of the thiophenol precursor suffered from low yields and difficult workup procedures. To support the translational research of [11C]mG4P012 and the other potential applications, we have developed a new route for synthesis of the thiophenol precursor and optimized the reaction conditions. The synthesis of N-(4-chloro-3-mercaptophenyl)picolinamide from 1-chloro-4-nitrobenzene has been greatly improved from 8% to 52% total yield with easy handling and in gram scales.
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Affiliation(s)
- Junfeng Wang
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, 149 Thirteenth Street, Suite 2301 Charlestown, MA 02129
- Gordon Center for Medical Imaging, Massachusetts General Hospital and Harvard Medical School, 125 Nashua Street, Suite 660, Boston, MA 02114
| | - Timothy M. Shoup
- Gordon Center for Medical Imaging, Massachusetts General Hospital and Harvard Medical School, 125 Nashua Street, Suite 660, Boston, MA 02114
| | - Anna-Liisa Brownell
- Gordon Center for Medical Imaging, Massachusetts General Hospital and Harvard Medical School, 125 Nashua Street, Suite 660, Boston, MA 02114
| | - Zhaoda Zhang
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, 149 Thirteenth Street, Suite 2301 Charlestown, MA 02129
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Coughlin Q, Hopper AT, Blanco MJ, Tirunagaru V, Robichaud AJ, Doller D. Allosteric Modalities for Membrane-Bound Receptors: Insights from Drug Hunting for Brain Diseases. J Med Chem 2019; 62:5979-6002. [PMID: 30721063 DOI: 10.1021/acs.jmedchem.8b01651] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Medicinal chemists are accountable for embedding the appropriate drug target profile into the molecular architecture of a clinical candidate. An accurate characterization of the functional effects following binding of a drug to its biological target is a fundamental step in the discovery of new medicines, informing the translation of preclinical efficacy and safety observations into human trials. Membrane-bound proteins, particularly ion channels and G protein-coupled receptors (GPCRs), are biological targets prone to allosteric modulation. Investigations using allosteric drug candidates and chemical tools suggest that their functional effects may be tailored with a high degree of translational alignment, making them molecular tools to correct pathophysiological functional tone and enable personalized medicine when a causative target-to-disease link is known. We present select examples of functional molecular fine-tuning of allosterism and discuss consequences relevant to drug design.
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Rovira X, Trapero A, Pittolo S, Zussy C, Faucherre A, Jopling C, Giraldo J, Pin JP, Gorostiza P, Goudet C, Llebaria A. OptoGluNAM4.1, a Photoswitchable Allosteric Antagonist for Real-Time Control of mGlu4 Receptor Activity. Cell Chem Biol 2016; 23:929-34. [PMID: 27478159 DOI: 10.1016/j.chembiol.2016.06.013] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Revised: 06/06/2016] [Accepted: 06/07/2016] [Indexed: 11/17/2022]
Abstract
OptoGluNAM4.1, a negative allosteric modulator (NAM) of metabotropic glutamate receptor 4 (mGlu4) contains a reactive group that covalently binds to the receptor and a blue-light-activated, fast-relaxing azobenzene group that allows reversible receptor activity photocontrol in vitro and in vivo. OptoGluNAM4.1 induces light-dependent behavior in zebrafish and reverses the activity of the mGlu4 agonist LSP4-2022 in a mice model of chronic pain, defining a photopharmacological tool to better elucidate the physiological roles of the mGlu4 receptor in the nervous system.
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Affiliation(s)
- Xavier Rovira
- Institut de Génomique Fonctionnelle, CNRS, UMR-5203, Université de Montpellier, 34000 Montpellier, France; INSERM, U1191, 34000 Montpellier, France
| | - Ana Trapero
- Laboratory of Medicinal Chemistry, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), 08034 Barcelona, Spain; Institute for Bioengineering of Catalonia (IBEC), 08028 Barcelona, Spain
| | - Silvia Pittolo
- Institute for Bioengineering of Catalonia (IBEC), 08028 Barcelona, Spain
| | - Charleine Zussy
- Institut de Génomique Fonctionnelle, CNRS, UMR-5203, Université de Montpellier, 34000 Montpellier, France; INSERM, U1191, 34000 Montpellier, France
| | - Adèle Faucherre
- Institut de Génomique Fonctionnelle, CNRS, UMR-5203, Université de Montpellier, 34000 Montpellier, France; INSERM, U1191, 34000 Montpellier, France
| | - Chris Jopling
- Institut de Génomique Fonctionnelle, CNRS, UMR-5203, Université de Montpellier, 34000 Montpellier, France; INSERM, U1191, 34000 Montpellier, France
| | - Jesús Giraldo
- Laboratory of Molecular Neuropharmacology and Bioinformatics, Institut de Neurociències and Unitat de Bioestadística, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle, CNRS, UMR-5203, Université de Montpellier, 34000 Montpellier, France; INSERM, U1191, 34000 Montpellier, France
| | - Pau Gorostiza
- Institute for Bioengineering of Catalonia (IBEC), 08028 Barcelona, Spain; Network Biomedical Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Poeta Mariano Esquillor s/n, Zaragoza 50018, Spain; ICREA, Pg. Lluís Companys, 23, Barcelona 08010, Spain.
| | - Cyril Goudet
- Institut de Génomique Fonctionnelle, CNRS, UMR-5203, Université de Montpellier, 34000 Montpellier, France; INSERM, U1191, 34000 Montpellier, France.
| | - Amadeu Llebaria
- Laboratory of Medicinal Chemistry, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), 08034 Barcelona, Spain.
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Synthesis and evaluation of N-(methylthiophenyl)picolinamide derivatives as PET radioligands for metabotropic glutamate receptor subtype 4. Bioorg Med Chem Lett 2015; 26:133-9. [PMID: 26602273 DOI: 10.1016/j.bmcl.2015.11.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 11/03/2015] [Accepted: 11/05/2015] [Indexed: 12/19/2022]
Abstract
In recent years, mGlu4 has received great research attention because of the potential benefits of mGlu4 activation in treating numerous brain disorders, such as Parkinson's disease (PD). A specific mGlu4 PET radioligand could be an important tool in understanding the role of mGlu4 in both healthy and disease conditions, and also for the development of new drugs. In this study, we synthesized four new N-(methylthiophenyl)picolinamide derivatives 11-14. Of these ligands, 11 and 14 showed high in vitro binding affinity for mGlu4 with IC50 values of 3.4nM and 3.1nM, respectively, and suitable physicochemical parameters. Compound 11 also showed enhanced metabolic stability and good selectivity to other mGluRs. [(11)C]11 and [(11)C]14 were radiolabeled using the [(11)C]methylation of the thiophenol precursors 20a and 20c with [(11)C]CH3I in 19.0% and 34.8% radiochemical yields (RCY), and their specific activities at the end of synthesis (EOS) were 496±138GBq/μmol (n=6) and 463±263GBq/μmol (n=4), respectively. The PET studies showed that [(11)C]11 accumulated fast into the brain and had higher uptake, slower washout and 25% better contrast than [(11)C]2, indicating improved imaging characteristics as PET radiotracer for mGlu4 compared to [(11)C]2. Therefore, [(11)C]11 will be a useful radioligand to investigate mGlu4 in different biological applications.
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Wierońska JM, Zorn SH, Doller D, Pilc A. Metabotropic glutamate receptors as targets for new antipsychotic drugs: Historical perspective and critical comparative assessment. Pharmacol Ther 2015; 157:10-27. [PMID: 26549541 DOI: 10.1016/j.pharmthera.2015.10.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In this review, we aim to present, discuss and clarify our current understanding regarding the prediction of possible antipsychotic effects of metabotropic glutamate (mGlu) receptor ligands. The number of preclinical trials clearly indicates, that this group of compounds constitutes an excellent alternative to presently used antipsychotic therapy, being effective not only to positive, but also negative and cognitive symptoms of schizophrenia. Although the results of clinical trials that were performed for the group of mGlu2/3 agonists were not so enthusiastic as in animal studies, they still showed that mGlu ligands do not induced variety of side effects typical for presently used antipsychotics, and were generally well tolerated. The lack of satisfactory effectiveness towards schizophrenia symptoms of mGlu2/3 activators in humans could be a result of variety of uncontrolled factors and unidentified biomarkers different for each schizophrenia patient, that should be taken into consideration in the future set of clinical trials. The subject is still open for further research, and the novel classes of mGlu5 or mGlu2/3 agonists/PAMs were recently introduced, including the large group of compounds from the third group of mGlu receptors, especially of mGlu4 subtype. Finally, more precise treatment based on simultaneous administration of minimal doses of the ligands for two or more receptors, seems to be promising in the context of symptoms-specific schizophrenia treatment.
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Affiliation(s)
- Joanna M Wierońska
- Institute of Pharmacology, Polish Academy of Sciences, 31-343 Krakow, Poland
| | | | | | - Andrzej Pilc
- Institute of Pharmacology, Polish Academy of Sciences, 31-343 Krakow, Poland.
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