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Qneibi M, Bdir S, Bdair M, Aldwaik SA, Sandouka D, Heeh M, Idais TI. AMPA receptor neurotransmission and therapeutic applications: A comprehensive review of their multifaceted modulation. Eur J Med Chem 2024; 266:116151. [PMID: 38237342 DOI: 10.1016/j.ejmech.2024.116151] [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: 12/14/2023] [Revised: 01/02/2024] [Accepted: 01/11/2024] [Indexed: 02/05/2024]
Abstract
The neuropharmacological community has shown a strong interest in AMPA receptors as critical components of excitatory synaptic transmission during the last fifteen years. AMPA receptors, members of the ionotropic glutamate receptor family, allow rapid excitatory neurotransmission in the brain. AMPA receptors, which are permeable to sodium and potassium ions, manage the bulk of the brain's rapid synaptic communications. This study thoroughly examines the recent developments in AMPA receptor regulation, focusing on a shift from single chemical illustrations to a more extensive investigation of underlying processes. The complex interplay of these modulators in modifying the function and structure of AMPA receptors is the main focus, providing insight into their influence on the speed of excitatory neurotransmission. This research emphasizes the potential of AMPA receptor modulation as a therapy for various neurological disorders such as epilepsy and Alzheimer's disease. Analyzing these regulators' sophisticated molecular details enhances our comprehension of neuropharmacology, representing a significant advancement in using AMPA receptors for treating intricate neurological conditions.
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Affiliation(s)
- Mohammad Qneibi
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine.
| | - Sosana Bdir
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
| | - Mohammad Bdair
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
| | - Samia Ammar Aldwaik
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
| | - Dana Sandouka
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
| | | | - Tala Iyad Idais
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
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2
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Scognamiglio PL, Vicidomini C, Roviello GN. Dancing with Nucleobases: Unveiling the Self-Assembly Properties of DNA and RNA Base-Containing Molecules for Gel Formation. Gels 2023; 10:16. [PMID: 38247739 PMCID: PMC10815473 DOI: 10.3390/gels10010016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 12/15/2023] [Accepted: 12/21/2023] [Indexed: 01/23/2024] Open
Abstract
Nucleobase-containing molecules are compounds essential in biology due to the fundamental role of nucleic acids and, in particular, G-quadruplex DNA and RNA in life. Moreover, some molecules different from nucleic acids isolated from different vegetal sources or microorganisms show nucleobase moieties in their structure. Nucleoamino acids and peptidyl nucleosides belong to this molecular class. Closely related to the above, nucleopeptides, also known as nucleobase-bearing peptides, are chimeric derivatives of synthetic origin and more rarely isolated from plants. Herein, the self-assembly properties of a vast number of structures, belonging to the nucleic acid and nucleoamino acid/nucleopeptide family, are explored in light of the recent scientific literature. Moreover, several technologically relevant properties, such as the hydrogelation ability of some of the nucleobase-containing derivatives, are reviewed in order to make way for future experimental investigations of newly devised nucleobase-driven hydrogels. Nucleobase-containing molecules, such as mononucleosides, DNA, RNA, quadruplex (G4)-forming oligonucleotides, and nucleopeptides are paramount in gel and hydrogel formation owing to their distinctive molecular attributes and ability to self-assemble in biomolecular nanosystems with the most diverse applications in different fields of biomedicine and nanotechnology. In fact, these molecules and their gels present numerous advantages, underscoring their significance and applicability in both material science and biomedicine. Their versatility, capability for molecular recognition, responsiveness to stimuli, biocompatibility, and biodegradability collectively contribute to their prominence in modern nanotechnology and biomedicine. In this review, we emphasize the critical role of nucleobase-containing molecules of different nature in pioneering novel materials with multifaceted applications, highlighting their potential in therapy, diagnostics, and new nanomaterials fabrication as required for addressing numerous current biomedical and nanotechnological challenges.
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Affiliation(s)
| | - Caterina Vicidomini
- Institute of Biostructures and Bioimaging, Italian National Council for Research (IBB-CNR), Area di Ricerca Site and Headquarters, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Giovanni N. Roviello
- Institute of Biostructures and Bioimaging, Italian National Council for Research (IBB-CNR), Area di Ricerca Site and Headquarters, Via Pietro Castellino 111, 80131 Naples, Italy
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3
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Chałupnik P, Szymańska E. Kainate Receptor Antagonists: Recent Advances and Therapeutic Perspective. Int J Mol Sci 2023; 24:1908. [PMID: 36768227 PMCID: PMC9916396 DOI: 10.3390/ijms24031908] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/06/2023] [Accepted: 01/16/2023] [Indexed: 01/21/2023] Open
Abstract
Since the 1990s, ionotropic glutamate receptors have served as an outstanding target for drug discovery research aimed at the discovery of new neurotherapeutic agents. With the recent approval of perampanel, the first marketed non-competitive antagonist of AMPA receptors, particular interest has been directed toward 'non-NMDA' (AMPA and kainate) receptor inhibitors. Although the role of AMPA receptors in the development of neurological or psychiatric disorders has been well recognized and characterized, progress in understanding the function of kainate receptors (KARs) has been hampered, mainly due to the lack of specific and selective pharmacological tools. The latest findings in the biology of KA receptors indicate that they are involved in neurophysiological activity and play an important role in both health and disease, including conditions such as anxiety, schizophrenia, epilepsy, neuropathic pain, and migraine. Therefore, we reviewed recent advances in the field of competitive and non-competitive kainate receptor antagonists and their potential therapeutic applications. Due to the high level of structural divergence among the compounds described here, we decided to divide them into seven groups according to their overall structure, presenting a total of 72 active compounds.
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Affiliation(s)
| | - Ewa Szymańska
- Department of Technology and Biotechnology of Drugs, Jagiellonian University Medical College in Kraków, PL 30-688 Kraków, Poland
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Willardiine and Its Synthetic Analogues: Biological Aspects and Implications in Peptide Chemistry of This Nucleobase Amino Acid. Pharmaceuticals (Basel) 2022; 15:ph15101243. [PMID: 36297355 PMCID: PMC9611319 DOI: 10.3390/ph15101243] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 09/27/2022] [Accepted: 09/28/2022] [Indexed: 12/16/2022] Open
Abstract
Willardiine is a nonprotein amino acid containing uracil, and thus classified as nucleobase amino acid or nucleoamino acid, that together with isowillardiine forms the family of uracilylalanines isolated more than six decades ago in higher plants. Willardiine acts as a partial agonist of ionotropic glutamate receptors and more in particular it agonizes the non-N-methyl-D-aspartate (non-NMDA) receptors of L-glutamate: ie. the α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) and kainate receptors. Several analogues and derivatives of willardiine have been synthesised in the laboratory in the last decades and these compounds show different binding affinities for the non-NMDA receptors. More in detail, the willardiine analogues have been employed not only in the investigation of the structure of AMPA and kainate receptors, but also to evaluate the effects of receptor activation in the various brain regions. Remarkably, there are a number of neurological diseases determined by alterations in glutamate signaling, and thus, ligands for AMPA and kainate receptors deserve attention as potential neurodrugs. In fact, similar to willardiine its analogues often act as agonists of AMPA and kainate receptors. A particular importance should be recognized to willardiine and its thymine-based analogue AlaT also in the peptide chemistry field. In fact, besides the naturally-occurring short nucleopeptides isolated from plant sources, there are different examples in which this class of nucleoamino acids was investigated for nucleopeptide development. The applications are various ranging from the realization of nucleopeptide/DNA chimeras for diagnostic applications, and nucleoamino acid derivatization of proteins for facilitating protein-nucleic acid interaction, to nucleopeptide-nucleopeptide molecular recognition for nanotechnological applications. All the above aspects on both chemistry and biotechnological applications of willardine/willardine-analogues and nucleopeptide will be reviewed in this work.
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Platonova YB, Volov AN, Tomilova LG. The synthesis and antituberculosis activity of 5-alkynyl uracil derivatives. Bioorg Med Chem Lett 2020; 30:127351. [DOI: 10.1016/j.bmcl.2020.127351] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/10/2020] [Accepted: 06/12/2020] [Indexed: 12/25/2022]
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Ignatowska J, Mironiuk-Puchalska E, Grześkowiak P, Wińska P, Wielechowska M, Bretner M, Karatsai O, Rędowicz MJ, Koszytkowska-Stawińska M. New insight into nucleo α-amino acids - Synthesis and SAR studies on cytotoxic activity of β-pyrimidine alanines. Bioorg Chem 2020; 100:103864. [PMID: 32446118 DOI: 10.1016/j.bioorg.2020.103864] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 04/15/2020] [Accepted: 04/17/2020] [Indexed: 12/14/2022]
Abstract
Three series of the β-pyrimidine alanines, including willardiine - a naturally occurring amino acid, were prepared from the l-serine-derived sulfamidates. Compounds 3b, 4a and 4b demonstrated antiproliferative activity toward the studied cancer cell lines, albeit the effect of these compounds on human brain astrocytoma MOG-G-CCM cells was more significant than on human neuroblastoma SK-N-AS cells. The cytosine analog of willardiine, compound 4b, reduced viability of MOG-G-CCM cells with EC50 = 36 ± 2 μM, more effectively than AMPA antagonist GYKI 52466. Willardiine showed possible capability of affecting invasiveness of glioblastoma U251 MG cells with no effect on their viability and morphology. Compound 3d, the ethyl ester of willardiine, featured activity toward binding domain hHS1S2I of the GluR2 receptor. Docking analysis revealed that the location mode of compound 3d at the S1S2 domain of hGluR2 (PDB ID: 3R7X) might differ from that of willardiine.
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Affiliation(s)
- Jolanta Ignatowska
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Ewa Mironiuk-Puchalska
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Piotr Grześkowiak
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Patrycja Wińska
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Monika Wielechowska
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Maria Bretner
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Olena Karatsai
- Laboratory of Molecular Basis of Cell Motility, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland
| | - Maria Jolanta Rędowicz
- Laboratory of Molecular Basis of Cell Motility, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland
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7
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Silva AR, Grosso C, Delerue-Matos C, Rocha JM. Comprehensive review on the interaction between natural compounds and brain receptors: Benefits and toxicity. Eur J Med Chem 2019; 174:87-115. [PMID: 31029947 DOI: 10.1016/j.ejmech.2019.04.028] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 04/10/2019] [Accepted: 04/11/2019] [Indexed: 02/06/2023]
Abstract
Given their therapeutic activity, natural products have been used in traditional medicines throughout the centuries. The growing interest of the scientific community in phytopharmaceuticals, and more recently in marine products, has resulted in a significant number of research efforts towards understanding their effect in the treatment of neurodegenerative diseases, such as Alzheimer's (AD), Parkinson (PD) and Huntington (HD). Several studies have shown that many of the primary and secondary metabolites of plants, marine organisms and others, have high affinities for various brain receptors and may play a crucial role in the treatment of diseases affecting the central nervous system (CNS) in mammalians. Actually, such compounds may act on the brain receptors either by agonism, antagonism, allosteric modulation or other type of activity aimed at enhancing a certain effect. The current manuscript comprehensively reviews the state of the art on the interactions between natural compounds and brain receptors. This information is of foremost importance when it is intended to investigate and develop cutting-edge drugs, more effective and with alternative mechanisms of action to the conventional drugs presently used for the treatment of neurodegenerative diseases. Thus, we reviewed the effect of 173 natural products on neurotransmitter receptors, diabetes related receptors, neurotrophic factor related receptors, immune system related receptors, oxidative stress related receptors, transcription factors regulating gene expression related receptors and blood-brain barrier receptors.
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Affiliation(s)
- Ana R Silva
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology (DB), University of Minho (UM), Campus Gualtar, P-4710-057, Braga, Portugal
| | - Clara Grosso
- REQUIMTE/LAQV, Instituto Superior de Engenharia do Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida, 431, P-4249-015, Porto, Portugal.
| | - Cristina Delerue-Matos
- REQUIMTE/LAQV, Instituto Superior de Engenharia do Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida, 431, P-4249-015, Porto, Portugal
| | - João M Rocha
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology (DB), University of Minho (UM), Campus Gualtar, P-4710-057, Braga, Portugal; REQUIMTE/LAQV, Grupo de investigação de Química Orgânica Aplicada (QUINOA), Laboratório de polifenóis alimentares, Departamento de Química e Bioquímica (DQB), Faculdade de Ciências da Universidade do Porto (FCUP), Rua do Campo Alegre, s/n, P-4169-007, Porto, Portugal
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8
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Mironiuk-Puchalska E, Buchowicz W, Grześkowiak P, Wińska P, Wielechowska M, Karatsai O, Rędowicz MJ, Bretner M, Koszytkowska-Stawińska M. Potential bioisosteres of β-uracilalanines derived from 1H-1,2,3-triazole-C-carboxylic acids. Bioorg Chem 2018; 83:500-510. [PMID: 30453142 DOI: 10.1016/j.bioorg.2018.10.061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 10/16/2018] [Accepted: 10/29/2018] [Indexed: 11/19/2022]
Abstract
The 1H-1,2,3-triazole-originated derivatives of willardiine were obtained by: (i) construction of the 1H-1,2,3-triazole ring in 1,3-dipolar cycloaddition of the uracil-derived azides and the carboxylate-bearing alkynes or α-acylphosphorus ylide, or (ii) N-alkylation of the uracil derivative with the 1H-1,2,3-triazole-4-carboxylate-derived mesylate. The latter method offered: (i) reproducible results, (ii) a significant reduction of amounts of auxiliary materials, (iii) reduction in wastes and (iv) reduction in a number of manual operations required for obtaining the reaction product. Compound 6a exhibited significant binding affinity to hHS1S2I ligand-binding domain of GluR2 receptor (EC50 = 2.90 µM) and decreased viability of human astrocytoma MOG-G-CCM cells in higher extent than known AMPA antagonist GYKI 52466.
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Affiliation(s)
- Ewa Mironiuk-Puchalska
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Włodzimierz Buchowicz
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Piotr Grześkowiak
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Patrycja Wińska
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Monika Wielechowska
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Olena Karatsai
- Laboratory of Molecular Basis of Cell Motility, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland
| | - Maria Jolanta Rędowicz
- Laboratory of Molecular Basis of Cell Motility, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland
| | - Maria Bretner
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
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9
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Krogsgaard-Larsen N, Delgar CG, Koch K, Brown PMGE, Møller C, Han L, Huynh THV, Hansen SW, Nielsen B, Bowie D, Pickering DS, Kastrup JS, Frydenvang K, Bunch L. Design and Synthesis of a Series of l-trans-4-Substituted Prolines as Selective Antagonists for the Ionotropic Glutamate Receptors Including Functional and X-ray Crystallographic Studies of New Subtype Selective Kainic Acid Receptor Subtype 1 (GluK1) Antagonist (2S,4R)-4-(2-Carboxyphenoxy)pyrrolidine-2-carboxylic Acid. J Med Chem 2016; 60:441-457. [PMID: 28005385 DOI: 10.1021/acs.jmedchem.6b01516] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Ionotropic glutamate receptor antagonists are valuable tool compounds for studies of neurological pathways in the central nervous system. On the basis of rational ligand design, a new class of selective antagonists, represented by (2S,4R)-4-(2-carboxyphenoxy)pyrrolidine-2-carboxylic acid (1b), for cloned homomeric kainic acid receptors subtype 1 (GluK1) was attained (Ki = 4 μM). In a functional assay, 1b displayed full antagonist activity with IC50 = 6 ± 2 μM. A crystal structure was obtained of 1b when bound in the ligand binding domain of GluK1. A domain opening of 13-14° was seen compared to the structure with glutamate, consistent with 1b being an antagonist. A structure-activity relationship study showed that the chemical nature of the tethering atom (C, O, or S) linking the pyrrolidine ring and the phenyl ring plays a key role in the receptor selectivity profile and that substituents on the phenyl ring are well accommodated by the GluK1 receptor.
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Affiliation(s)
| | | | | | - Patricia M G E Brown
- Bowie Lab, Department of Pharmacology & Therapeutics, Faculty of Medicine, McGill University , Montreal, Quebec H3G 0B1, Canada
| | | | | | | | | | | | - Derek Bowie
- Bowie Lab, Department of Pharmacology & Therapeutics, Faculty of Medicine, McGill University , Montreal, Quebec H3G 0B1, Canada
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10
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Weckenmann NM, Nachtsheim BJ. Enantioselective Synthesis ofD-α-(Uracil-5-yl)glycine Derivatives and Their Racemization-Free Incorporation into a Model Peptide. European J Org Chem 2015. [DOI: 10.1002/ejoc.201500914] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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11
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Synthesis and inhibitory effects of novel pyrimido-pyrrolo-quinoxalinedione analogues targeting nucleoproteins of influenza A virus H1N1. Eur J Med Chem 2015; 102:477-86. [PMID: 26310893 DOI: 10.1016/j.ejmech.2015.08.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 08/05/2015] [Accepted: 08/07/2015] [Indexed: 11/22/2022]
Abstract
The influenza nucleoprotein (NP) is a single-strand RNA-binding protein and the core of the influenza ribonucleoprotein (RNP) particle that serves many critical functions for influenza replication. NP has been considered as a promising anti-influenza target. A new class of anti-influenza compounds, nucleozin and analogues were reported recently in several laboratories to inhibit the synthesis of influenza macromolecules and prevent the cytoplasmic trafficking of the influenza RNP. In this study, pyrimido-pyrrolo-quinoxalinedione (PPQ) analogues as a new class of novel anti-influenza agents are reported. Compound PPQ-581 was identified as a potential anti-influenza lead with EC50 value of 1 μM for preventing virus-induced cytopathic effects. PPQ produces similar anti-influenza effects as nucleozin does in influenza-infected cells. Treatment with PPQ at the beginning of H1N1 infection inhibited viral protein synthesis, while treatment at later times blocked the RNP nuclear export and the appearance of cytoplasmic RNP aggregation. PPQ resistant H1N1 (WSN) viruses were isolated and found to have a NPS377G mutation. Recombinant WSN carrying the S377G NP is resistant to PPQ in anti-influenza and RNA polymerase assays. The WSN virus with the NPS377G mutation also is devoid of the PPQ-mediated RNP nuclear retention and cytoplasmic aggregation. The NPS377G expressing WSN virus is not resistant to the reported NP inhibitors nucleozin. Similarly, the nucleozin resistant WSN viruses are not resistant to PPQ, suggesting that PPQ targets a different site from the nucleozin-binding site. Our results also suggest that NP can be targeted through various binding sites to interrupt the crucial RNP trafficking, resulting in influenza replication inhibition.
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12
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Lima Neto JX, Fulco UL, Albuquerque EL, Corso G, Bezerra EM, Caetano EWS, da Costa RF, Freire VN. A quantum biochemistry investigation of willardiine partial agonism in AMPA receptors. Phys Chem Chem Phys 2015; 17:13092-103. [DOI: 10.1039/c4cp05630b] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We employ quantum biochemistry methods based on the Density Functional Theory (DFT) approach to unveil detailed binding energy features of willardiines co-crystallized with the AMPA receptor.
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Affiliation(s)
- José X. Lima Neto
- Departamento de Biofísica e Farmacologia
- Universidade Federal do Rio Grande do Norte
- Natal-RN
- Brazil
| | - Umberto L. Fulco
- Departamento de Biofísica e Farmacologia
- Universidade Federal do Rio Grande do Norte
- Natal-RN
- Brazil
| | | | - Gilberto Corso
- Departamento de Biofísica e Farmacologia
- Universidade Federal do Rio Grande do Norte
- Natal-RN
- Brazil
| | - Eveline M. Bezerra
- Departamento de Biofísica e Farmacologia
- Universidade Federal do Rio Grande do Norte
- Natal-RN
- Brazil
| | | | - Roner F. da Costa
- Departamento de Física
- Universidade Federal Rural do Semi-Árido
- 59780-000 Caraúbas-RN
- Brazil
| | - Valder N. Freire
- Departamento de Física
- Universidade Federal do Ceará
- Fortaleza-CE
- Brazil
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13
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Juknaitė L, Sugamata Y, Tokiwa K, Ishikawa Y, Takamizawa S, Eng A, Sakai R, Pickering DS, Frydenvang K, Swanson GT, Kastrup JS, Oikawa M. Studies on an (S)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptor antagonist IKM-159: asymmetric synthesis, neuroactivity, and structural characterization. J Med Chem 2013; 56:2283-93. [PMID: 23432124 PMCID: PMC4485398 DOI: 10.1021/jm301590z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
IKM-159 was developed and identified as a member of a new class of heterotricyclic glutamate analogues that act as AMPA receptor-selective antagonists. However, it was not known which enantiomer of IKM-159 was responsible for its pharmacological activities. Here, we report in vivo and in vitro neuronal activities of both enantiomers of IKM-159 prepared by enantioselective asymmetric synthesis. By employment of (R)-2-amino-2-(4-methoxyphenyl)ethanol as a chiral auxiliary, (2R)-IKM-159 and the (2S)-counterpart were successfully synthesized in 0.70% and 1.5% yields, respectively, over a total of 18 steps. Both behavioral and electrophysiological assays showed that the biological activity observed for the racemic mixture was reproduced only with (2R)-IKM-159, whereas the (2S)-counterpart was inactive in both assays. Racemic IKM-159 was crystallized with the ligand-binding domain of GluA2, and the structure revealed a complex containing (2R)-IKM-159 at the glutamate binding site. (2R)-IKM-159 locks the GluA2 in an open form, consistent with a pharmacological action as competitive antagonist of AMPA receptors.
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Affiliation(s)
- Lina Juknaitė
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen Ø, Denmark
| | - Yutaro Sugamata
- Graduate School of Nanobioscience, Yokohama City University, Seto 22-2, Kanazawa-ku, Yokohama 236-0027, Japan
| | - Kazuya Tokiwa
- Graduate School of Nanobioscience, Yokohama City University, Seto 22-2, Kanazawa-ku, Yokohama 236-0027, Japan
| | - Yuichi Ishikawa
- Graduate School of Nanobioscience, Yokohama City University, Seto 22-2, Kanazawa-ku, Yokohama 236-0027, Japan
| | - Satoshi Takamizawa
- Graduate School of Nanobioscience, Yokohama City University, Seto 22-2, Kanazawa-ku, Yokohama 236-0027, Japan
| | - Andrew Eng
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Feinberg School of Medicine, 303 East Chicago Avenue, Chicago, Illinois 60611, United States
| | - Ryuichi Sakai
- Faculty of Fisheries Sciences, Hokkaido University, Hakodate 041-8611, Japan
| | - Darryl S. Pickering
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen Ø, Denmark
| | - Karla Frydenvang
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen Ø, Denmark
| | - Geoffrey T. Swanson
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Feinberg School of Medicine, 303 East Chicago Avenue, Chicago, Illinois 60611, United States
| | - Jette S. Kastrup
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen Ø, Denmark
| | - Masato Oikawa
- Graduate School of Nanobioscience, Yokohama City University, Seto 22-2, Kanazawa-ku, Yokohama 236-0027, Japan
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14
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Ahmed AH, Wang S, Chuang HH, Oswald RE. Mechanism of AMPA receptor activation by partial agonists: disulfide trapping of closed lobe conformations. J Biol Chem 2011; 286:35257-66. [PMID: 21846932 PMCID: PMC3186401 DOI: 10.1074/jbc.m111.269001] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 07/08/2011] [Indexed: 11/06/2022] Open
Abstract
The mechanism by which agonist binding to an ionotropic glutamate receptor leads to channel opening is a central issue in molecular neurobiology. Partial agonists are useful tools for studying the activation mechanism because they produce full channel activation with lower probability than full agonists. Structural transitions that determine the efficacy of partial agonists can provide information on the trigger that begins the channel-opening process. The ligand-binding domain of AMPA receptors is a bilobed structure, and the closure of the lobes is associated with channel activation. One possibility is that partial agonists sterically block full lobe closure but that partial degrees of closure trigger the channel with a lower probability. Alternatively, full lobe closure may be required for activation, and the stability of the fully closed state could determine efficacy with the fully closed state having a lower stability when bound to partial relative to full agonists. Disulfide-trapping experiments demonstrated that even extremely low efficacy ligands such as 6-cyano-7-nitroquinoxaline-2,3-dione can produce a full lobe closure, presumably with low probability. The results are consistent the hypothesis that the efficacy is determined at least in part by the stability of the state in which the lobes are fully closed.
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Affiliation(s)
| | - Shu Wang
- Biomedical Sciences, Cornell University, Ithaca, New York 14853
| | - Huai-Hu Chuang
- Biomedical Sciences, Cornell University, Ithaca, New York 14853
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15
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Larsen AM, Bunch L. Medicinal chemistry of competitive kainate receptor antagonists. ACS Chem Neurosci 2011; 2:60-74. [PMID: 22778857 DOI: 10.1021/cn1001039] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Accepted: 11/27/2010] [Indexed: 01/06/2023] Open
Abstract
Kainic acid (KA) receptors belong to the group of ionotropic glutamate receptors and are expressed throughout in the central nervous system (CNS). The KA receptors have been shown to be involved in neurophysiological functions such as mossy fiber long-term potentiation (LTP) and synaptic plasticity and are thus potential therapeutic targets in CNS diseases such as schizophrenia, major depression, neuropathic pain and epilepsy. Extensive effort has been made to develop subtype-selective KA receptor antagonists in order to elucidate the physiological function of each of the five subunits known (GluK1-5). However, to date only selective antagonists for the GluK1 subunit have been discovered, which underlines the strong need for continued research in this area. The present review describes the structure-activity relationship and pharmacological profile for 10 chemically distinct classes of KA receptor antagonists comprising, in all, 45 compounds. To the medicinal chemist this information will serve as reference guidance as well as an inspiration for future effort in this field.
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Affiliation(s)
- Ann M. Larsen
- Department of Medicinal Chemistry, Faculty of Pharmaceutical
Sciences, University of Copenhagen, Universitetsparken 2, DK-2100
Copenhagen, Denmark
| | - Lennart Bunch
- Department of Medicinal Chemistry, Faculty of Pharmaceutical
Sciences, University of Copenhagen, Universitetsparken 2, DK-2100
Copenhagen, Denmark
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16
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Abstract
Glutamate receptors are key mediators of brain communication. Among ionotropic glutamate receptors, kainate receptors (KARs) have been least explored and their relevance to pathophysiology is relatively obscure. This is in part due to the relatively low abundance of KARs, the regulatory function in network activity they play, the lack of specific agonists and antagonists for this receptor subtype, as well as to the absence of striking phenotypes in mice deficient in KAR subunits. Nonetheless, it is now well established that KARs are located presynaptically whereby they regulate glutamate and GABA release, and thus, excitability and participate in short‐term plasticity. In turn, KARs are also located postsynaptically and their activation contributes to synaptic integration. The development of specific novel ligands is helping to further investigate the contribution of KARs to health and disease. In this review, I summarize current knowledge about KAR physiology and pharmacology, and discuss their involvement in cell death and disease. In addition, I recapitulate the available data about the use of KAR antagonists and receptor subunit deficient mice in experimental paradigms of brain diseases, as well as the main findings about KAR roles in human CNS disorders. In sum, subunit specific antagonists have therapeutic potential in neurodegenerative and psychiatric diseases as well as in epilepsy and pain. Knowledge about the genetics of KARs will also help to understand the pathophysiology of those and other illnesses.
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Affiliation(s)
- Carlos Matute
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED) and Departamento de Neurociencias, Universidad del País Vasco, 48940-Leioa, Spain.
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17
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Pøhlsgaard J, Frydenvang K, Madsen U, Kastrup JS. Lessons from more than 80 structures of the GluA2 ligand-binding domain in complex with agonists, antagonists and allosteric modulators. Neuropharmacology 2010; 60:135-50. [PMID: 20713069 DOI: 10.1016/j.neuropharm.2010.08.004] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 07/22/2010] [Accepted: 08/07/2010] [Indexed: 11/24/2022]
Abstract
Ionotropic glutamate receptors (iGluRs) constitute a family of ligand-gated ion channels that are essential for mediating fast synaptic transmission in the central nervous system. These receptors play an important role for the development and function of the nervous system, and are essential in learning and memory. However, iGluRs are also implicated in or have causal roles for several brain disorders, e.g. epilepsy, Alzheimer's disease, Parkinson's disease and schizophrenia. Their involvement in neurological diseases has stimulated widespread interest in their structure and function. Since the first publication in 1998 of the structure of a recombinant soluble protein comprising the ligand-binding domain of GluA2 extensive studies have afforded numerous crystal structures of wildtype and mutant proteins including different ligands. The structural information obtained combined with functional data have led to models for receptor activation and desensitization by agonists, inhibition by antagonists and block of desensitization by positive allosteric modulators. Furthermore, the structural and functional studies have formed a powerful platform for the design of new selective compounds.
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Affiliation(s)
- Jacob Pøhlsgaard
- Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
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18
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Robust short-latency perisomatic inhibition onto neocortical pyramidal cells detected by laser-scanning photostimulation. J Neurosci 2009; 29:7413-23. [PMID: 19515909 DOI: 10.1523/jneurosci.6098-08.2009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Inhibitory connectivity onto neocortical pyramidal cells was mapped using LSPS (laser-scanning photostimulation/glutamate uncaging). The average onset latency of IPSCs was shorter than that of EPSCs recorded in the same cells, indicating a specific mechanism for rapid network recruitment of inhibition. The majority of strong inhibitory synaptic inputs originated within 300 mum of the recorded cell's soma, had onset latencies between 4 and 10 ms, and high amplitude [short-latency IPSCs (slIPSCs)]. slIPSCs were GABA(A) receptor- mediated chloride currents that were evoked in an all-or-none manner. We tested whether slIPSCs resulted from somatic depolarization of presynaptic interneurons or from direct excitation of inhibitory presynaptic terminals via kainate receptors. Our evidence supports the former hypothesis: (1) slIPSCs had similar sensitivity to kainate and AMPA receptor blockers as electrically evoked EPSCs. (2) slIPSCs frequently had an notched rising phase suggestive of summated IPSCs resulting from repetitive firing of presynaptic neurons. (3) Latencies and interevent intervals were consistent with spike latencies and interspike intervals in fast-spiking (FS) interneurons. (4) slIPSCs were frequently evoked at spots where the recorded cell was also excited directly, but approximately 15% of spots from which slIPSCs were evoked did not overlap with the recorded neuron's cell body. We propose that slIPSCs from FS interneurons represent a pool of powerful inhibitory signals that can be recruited by local excitation. Because of their magnitude, progressive recruitment, and short latency, slIPSCs are a effective mechanism of regulating excitability in neocortical circuits.
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19
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Dargan SL, Clarke VRJ, Alushin GM, Sherwood JL, Nisticò R, Bortolotto ZA, Ogden AM, Bleakman D, Doherty AJ, Lodge D, Mayer ML, Fitzjohn SM, Jane DE, Collingridge GL. ACET is a highly potent and specific kainate receptor antagonist: characterisation and effects on hippocampal mossy fibre function. Neuropharmacology 2009; 56:121-30. [PMID: 18789344 PMCID: PMC2637447 DOI: 10.1016/j.neuropharm.2008.08.016] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Revised: 08/04/2008] [Accepted: 08/07/2008] [Indexed: 11/24/2022]
Abstract
Kainate receptors (KARs) are involved in both NMDA receptor-independent long-term potentiation (LTP) and synaptic facilitation at mossy fibre synapses in the CA3 region of the hippocampus. However, the identity of the KAR subtypes involved remains controversial. Here we used a highly potent and selective GluK1 (formerly GluR5) antagonist (ACET) to elucidate roles of GluK1-containing KARs in these synaptic processes. We confirmed that ACET is an extremely potent GluK1 antagonist, with a Kb value of 1.4+/-0.2 nM. In contrast, ACET was ineffective at GluK2 (formerly GluR6) receptors at all concentrations tested (up to 100 microM) and had no effect at GluK3 (formerly GluR7) when tested at 1 microM. The X-ray crystal structure of ACET bound to the ligand binding core of GluK1 was similar to the UBP310-GluK1 complex. In the CA1 region of hippocampal slices, ACET was effective at blocking the depression of both fEPSPs and monosynaptically evoked GABAergic transmission induced by ATPA, a GluK1 selective agonist. In the CA3 region of the hippocampus, ACET blocked the induction of NMDA receptor-independent mossy fibre LTP. To directly investigate the role of pre-synaptic GluK1-containing KARs we combined patch-clamp electrophysiology and 2-photon microscopy to image Ca2+ dynamics in individual giant mossy fibre boutons. ACET consistently reduced short-term facilitation of pre-synaptic calcium transients induced by 5 action potentials evoked at 20-25Hz. Taken together our data provide further evidence for a physiological role of GluK1-containing KARs in synaptic facilitation and LTP induction at mossy fibre-CA3 synapses.
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Affiliation(s)
- Sheila L Dargan
- MRC Centre for Synaptic Plasticity, University of Bristol, Bristol BS8 1TD, UK.
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20
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Kainate receptors: Pharmacology, function and therapeutic potential. Neuropharmacology 2009; 56:90-113. [DOI: 10.1016/j.neuropharm.2008.08.023] [Citation(s) in RCA: 203] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2008] [Revised: 08/04/2008] [Accepted: 08/07/2008] [Indexed: 01/28/2023]
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21
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Kadieva MG, Oganesyan ÉT, Zefirova OH. Antagonists of AMPA/KA and NMDA (glycine site) glutamate receptors. Pharm Chem J 2008. [DOI: 10.1007/s11094-008-0063-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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22
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Ren M, Yoshimura Y, Takada N, Horibe S, Komatsu Y. Specialized inhibitory synaptic actions between nearby neocortical pyramidal neurons. Science 2007; 316:758-61. [PMID: 17478724 DOI: 10.1126/science.1135468] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
We found that, in the mouse visual cortex, action potentials generated in a single layer-2/3 pyramidal (excitatory) neuron can reliably evoke large, constant-latency inhibitory postsynaptic currents in other nearby pyramidal cells. This effect is mediated by axo-axonic ionotropic glutamate receptor-mediated excitation of the nerve terminals of inhibitory interneurons, which connect to the target pyramidal cells. Therefore, individual cortical excitatory neurons can generate inhibition independently from the somatic firing of inhibitory interneurons.
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Affiliation(s)
- Ming Ren
- Department of Neuroscience, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan
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23
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Abstract
Glutamic acid (Glu) is the major excitatory neurotransmitter in the mammalian central nervous system (CNS) where it is involved in the physiological regulation of different processes. It has been well established that excessive endogenous Glu is associated with many acute and chronic neurodegenerative disorders such as cerebral ischaemia, epilepsy, amiotrophic lateral sclerosis, Parkinson's, and Alzheimer's disease. These data have consequently added great impetus to the research in this field. In fact, many Glu receptor antagonists acting at the N-methyl-D-aspartic acid (NMDA), 2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA), and/or kainic acid (KA) receptors have been developed as research tools and potential therapeutic agents. Ligands showing competitive antagonistic action at the AMPA type of Glu receptors were first reported in 1988, and the systemically active 2,3-dihydroxy-6-nitro-7-sulphamoyl-benzo[f]quinoxaline (NBQX) was first shown to have useful therapeutic effects in animal models of neurological disease in 1990. Since then, the quinoxaline template has represented the backbone of various competitive AMPA receptor antagonists belonging to different classes which had been developed in order to increase potency, selectivity and water solubility, but also to prolong the "in vivo" action. Compounds that present better pharmacokinetic properties and less serious adverse effects with respect to the others previously developed are undergoing clinical evaluation. In the near future, the most important clinical application for the AMPA receptor antagonists will probably be as neuroprotectant in neurodegenerative diseases, such as epilepsy, for the treatment of patients not responding to current therapies. The present review reports the history of competitive AMPA receptor antagonists from 1988 up to today, providing a systematic coverage of both the open and patent literature.
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Affiliation(s)
- Daniela Catarzi
- Dipartimento di Scienze Farmaceutiche, Universita' degli Studi di Firenze, Polo Scientifico, Via U. Schiff, 6-50019 Sesto Fiorentino (Firenze), Italy.
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24
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Greenwood JR, Mewett KN, Allan RD, Martín BO, Pickering DS. 3-Hydroxypyridazine 1-oxides as carboxylate bioisosteres: A new series of subtype-selective AMPA receptor agonists. Neuropharmacology 2006; 51:52-9. [PMID: 16631211 DOI: 10.1016/j.neuropharm.2006.02.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2005] [Revised: 01/28/2006] [Accepted: 02/24/2006] [Indexed: 11/19/2022]
Abstract
Three positional isomers (compounds 1, 2, and 3) of 1-uracilylalanine (willardiine) based on a 3-hydroxypyridazine 1-oxide scaffold with an alanine side-chain at positions 4 (1), 5 (2) or 6 (3) were tested for binding to recombinant homomeric AMPA receptor (AMPA-R) subtypes GluR1-4, as well for excitatory activity on the rat cortical wedge preparation. 1 had approximately 30 times higher affinity than willardiine while showing a similar selectivity profile, i.e. 22-fold selectivity for GluR1/2 over GluR3/4. The GluR1-4 affinities of 3 were similar to 1, however, its 31-fold selectivity for GluR1/2 over GluR3/4 is the highest yet observed among azine-based glutamate analogues. The non-isosteric congener 2 showed weaker binding to AMPA-Rs. In the cortical wedge, 1 evokes similar responses to AMPA, while 3 and 2 are 10- and 100-fold weaker, respectively. Dose-response curves on Xenopus laevis oocytes expressing GluR1-4(flip) confirmed that 1 and 3 are potent GluR1/2 receptor agonists (EC(50)s from 0.26 to 1.7microM) but are 10- to 160-fold less potent at GluR3/4. The structures, potencies and selectivities of this new class of AMPA agonists are compared with those of willardiine, 5-fluorowillardiine and azawillardiine, referring to the binding mode observed in the crystal structure of willardiine bound to GluR2-S1S2. The results indicate that the 3-hydroxypyridazine 1-oxide moiety can function as an outstanding carboxylate mimic at AMPA-Rs, leading the way to further fine-tuning of subtype selectivity. This little-explored molecular motif may find wider application in medicinal chemistry.
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Affiliation(s)
- Jeremy R Greenwood
- Department of Medicinal Chemistry, Danish University of Pharmaceutical Sciences, Universitetsparken 2, DK 2100 Copenhagen, Denmark
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25
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Shen Y, Linden DJ. Long-term potentiation of neuronal glutamate transporters. Neuron 2005; 46:715-22. [PMID: 15924858 DOI: 10.1016/j.neuron.2005.04.033] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2004] [Revised: 02/02/2005] [Accepted: 04/28/2005] [Indexed: 01/21/2023]
Abstract
Persistent, use-dependent modulation of synaptic strength has been demonstrated for fast synaptic transmission mediated by glutamate and has been hypothesized to underlie persistent behavioral changes ranging from memory to addiction. Glutamate released at synapses is sequestered by the action of excitatory amino acid transporters (EAATs) in glia and postsynaptic neurons. So, the efficacy of glutamate transporter function is crucial for regulating glutamate spillover to adjacent presynaptic and postsynaptic receptors and the consequent induction of plastic or excitotoxic processes. Here, we report that tetanic stimulation of cerebellar climbing fiber-Purkinje cell synapses results in long-term potentiation (LTP) of a climbing fiber-evoked glutamate transporter current recorded in Purkinje cells. This LTP is postsynaptically expressed and requires activation of an mGluR1/PKC cascade. Together with a simultaneously induced long-term depression (LTD) of postsynaptic AMPA receptors, this might reflect an integrated antiexcitotoxic cellular response to strong climbing fiber synaptic activation, as occurs following an ischemic episode.
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Affiliation(s)
- Ying Shen
- Department of Neuroscience, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205, USA
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26
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27
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Sharifullina E, Ostroumov K, Nistri A. Metabotropic glutamate receptor activity induces a novel oscillatory pattern in neonatal rat hypoglossal motoneurones. J Physiol 2004; 563:139-59. [PMID: 15611018 PMCID: PMC1665569 DOI: 10.1113/jphysiol.2004.079509] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Tongue muscles innervated by the hypoglossal nerves play a crucial role to ensure airway patency and milk suckling in the neonate. Using a slice preparation of the neonatal rat brain, we investigated the electrophysiological characteristics of hypoglossal motoneurones in the attempt to identify certain properties potentially capable of synchronizing motor commands to the tongue. Bath-applied DHPG, a selective agonist of group I metabotropic glutamate receptors (mGluRs), generated persistent, regular electrical oscillations (4-8 Hz) recorded from patch-clamped motoneurones. Under voltage clamp, oscillations were biphasic events, comprising large outward slow currents alternated with fast, repeated inward currents. Electrical oscillations had amplitude and period insensitive to cell membrane potential, and required intact glutamatergic transmission via AMPA receptors. Oscillations were mediated by subtype 1 receptors of group I mGluRs (mGluR1s), and were routinely observed during pharmacological block of glycinergic and GABAergic inhibition, although they could also be recorded in standard saline. Simultaneous recordings from pairs of motoneurones within the same hypoglossal nucleus demonstrated that oscillations were due to their strong electrical coupling and were blocked by the gap junction blocker carbenoxolone. Pacing of slow oscillations apparently depended on the operation of K(ATP) channels in view of the block by tolbutamide or glibenclamide. Under current clamp, oscillations generated more regular spike firing of motoneurones and facilitated glutamatergic excitatory inputs. These data suggest that neonatal motoneurones of the nucleus hypoglossus possess a formerly undisclosed ability to express synchronous electrical oscillations, unveiled by activation of mGluR1s.
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Affiliation(s)
- Elina Sharifullina
- Neurobiology Sector and INFM Unit, International School for Advanced Studies (SISSA), Trieste, Italy
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28
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More JCA, Nistico R, Dolman NP, Clarke VRJ, Alt AJ, Ogden AM, Buelens FP, Troop HM, Kelland EE, Pilato F, Bleakman D, Bortolotto ZA, Collingridge GL, Jane DE. Characterisation of UBP296: a novel, potent and selective kainate receptor antagonist. Neuropharmacology 2004; 47:46-64. [PMID: 15165833 DOI: 10.1016/j.neuropharm.2004.03.005] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2003] [Revised: 02/23/2004] [Accepted: 03/01/2004] [Indexed: 10/26/2022]
Abstract
Willardiine derivatives with an N3-benzyl substituent bearing an acidic group have been synthesized with the aim of producing selective antagonists for GLUK5-containing kainate receptors. UBP296 was found to be a potent and selective antagonist of native GLUK5-containing kainate receptors in the spinal cord, with activity residing in the S enantiomer (UBP302). In cells expressing human kainate receptor subunits, UBP296 selectively depressed glutamate-induced calcium influx in cells containing GLUK5 in homomeric or heteromeric forms. In radioligand displacement binding studies, the willardiine analogues displaced [3H]kainate binding with IC50 values >100 microM at rat GLUK6, GLUK2 or GLUK6/GLUK2. An explanation of the GLUK5 selectivity of UBP296 was obtained using homology models of the antagonist bound forms of GLUK5 and GLUK6. In rat hippocampal slices, UBP296 reversibly blocked ATPA-induced depressions of synaptic transmission at concentrations subthreshold for affecting AMPA receptor-mediated synaptic transmission directly. UBP296 also completely blocked the induction of mossy fibre LTP, in medium containing 2 mM (but not 4 mM) Ca2+. These data provide further evidence for a role for GLUK5-containing kainate receptors in mossy fibre LTP. In conclusion, UBP296 is the most potent and selective antagonist of GLUK5-containing kainate receptors so far described.
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Affiliation(s)
- Julia C A More
- Department of Pharmacology, MRC Centre for Synaptic Plasticity, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK
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