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Gargiulo API, Acuña A, Gargiulo MML, Gargiulo ÁJM, Gargiulo MCJ, Baiardi GC, Mora S, Lafuente JV, Romanowicz E, Landa AI, Guevara MA, Gargiulo PÁ. Effects of Cycloleucine in the Nucleus Accumbens Septi on the Elevated plus Maze Test in Rats. Neuropsychobiology 2021; 79:191-197. [PMID: 31927553 DOI: 10.1159/000505069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Accepted: 11/26/2019] [Indexed: 11/19/2022]
Abstract
INTRODUCTION In recent years, an important number of studies have emphasized the psychopharmacological actions of cycloleucine (1-aminocyclopentanecarboxylic acid) acting on the NR1 subunit (glycine allosteric site) of NMDA (N-methyl-D-aspartic acid) receptor. We studied the effects of its injection in an anxiety test. METHODS The elevated plus maze test was used. Male rats bilaterally cannulated into the nucleus accumbens septi (NAS) were employed. Rats were divided into 5 groups that received either 1 µL injections of saline or cycloleucine (0.5, 1, 2, or 4 µg) 15 min before testing. RESULTS Time spent in the open arm was significantly increased by cycloleucine treatment with all doses (1 and 2 µg, p < 0.05; 0.5 and 4 µg, p < 0.01), like number of extreme arrivals (0.5 and 1 µg, p < 0.05; 2 µg, p < 0.01; and 4 µg, p < 0.001). Open arm entries were increased by the highest dose only (4 µg, p < 0.01). DISCUSSION/CONCLUSION Present results show no difference between all doses in the time spent in the open arm, suggesting an indirect, noncompetitive action of the drug. The increase in extreme arrivals and open arm entries suggests a dose influence in these parameters. We conclude that cycloleucine influence on the NMDA receptors within NAS leads to anxiolytic-like effects and behavioral disinhibition, which once more confirms the involvement of NAS in anxiety processing.
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Affiliation(s)
- Augusto P I Gargiulo
- Laboratory of Neurosciences and Experimental Psychology, CONICET, Department of Pathology, Faculty of Medical Sciences, National University of Cuyo, Mendoza, Argentina
| | - Andrés Acuña
- Laboratory of Neurosciences and Experimental Psychology, CONICET, Department of Pathology, Faculty of Medical Sciences, National University of Cuyo, Mendoza, Argentina
| | - Mercedes M L Gargiulo
- Laboratory of Neurosciences and Experimental Psychology, CONICET, Department of Pathology, Faculty of Medical Sciences, National University of Cuyo, Mendoza, Argentina
| | - Ángel J M Gargiulo
- Laboratory of Neurosciences and Experimental Psychology, CONICET, Department of Pathology, Faculty of Medical Sciences, National University of Cuyo, Mendoza, Argentina
| | - Marcos C J Gargiulo
- Laboratory of Neurosciences and Experimental Psychology, CONICET, Department of Pathology, Faculty of Medical Sciences, National University of Cuyo, Mendoza, Argentina
| | - Gustavo C Baiardi
- Laboratory of Neuropharmacology, Institute of Biological and Technological Research (IIBYT-CONICET), National University of Córdoba, Faculty of Chemical Sciences, Catholic University of Córdoba, Córdoba, Argentina
| | - Sergio Mora
- Program of Molecular and Clinical Pharmacology, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago de Chile, Chile
| | - José Vicente Lafuente
- Laboratory of Clinical and Experimental Neurosciences (LaNCE), Department of Neuroscience, University of the Basque Country (UPV/EHU)-Barrio Sarriena, Leioa, Spain
| | - Esteban Romanowicz
- Laboratory of Neurosciences and Experimental Psychology, CONICET, Department of Pathology, Faculty of Medical Sciences, National University of Cuyo, Mendoza, Argentina
| | - Adriana I Landa
- Laboratory of Neurosciences and Experimental Psychology, CONICET, Department of Pathology, Faculty of Medical Sciences, National University of Cuyo, Mendoza, Argentina
| | - Manuel A Guevara
- Laboratory of Neurosciences and Experimental Psychology, CONICET, Department of Pathology, Faculty of Medical Sciences, National University of Cuyo, Mendoza, Argentina
| | - Pascual Ángel Gargiulo
- Laboratory of Neurosciences and Experimental Psychology, CONICET, Department of Pathology, Faculty of Medical Sciences, National University of Cuyo, Mendoza, Argentina,
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Fung T, Asiri YI, Taheri K, Wall R, Schwarz SKW, Puil E, MacLeod BA. Antinociception by intrathecal delivery of the novel non-opioid 1-amino-1-cyclobutanecarboxylic acid. Eur J Pain 2018; 23:260-271. [PMID: 30091274 DOI: 10.1002/ejp.1301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 08/02/2018] [Accepted: 08/03/2018] [Indexed: 11/11/2022]
Abstract
BACKGROUND Neuraxial opioids are widely used for intraoperative and post-operative analgesia. The risk of severe adverse effects including respiratory depression accompanies this analgesia, prompting the need for effective non-opioid alternatives. Systemic 1-amino-1-cyclobutanecarboxylic acid showed promise in preliminary studies to produce antinociception without observable toxicity. However, the effects of 1-amino-1-cyclobutanecarboxylic acid after intrathecal administration are unknown. The aim of this study was to determine whether intrathecal administration of 1-amino-1-cyclobutanecarboxylic acid produces antinociceptive effects in murine models and to elucidate its site and receptor mechanism of action. METHODS Female CD-1 mice were randomized to receive intrathecal, intraperitoneal and intraplantar injections of 1-amino-1-cyclobutanecarboxylic acid. Animals receiving intrathecal injections were anaesthetized and injected between L5 and L6. Animals then received an intraplantar injection of 10% hypertonic saline into the right hindpaw and were video-recorded for 30 min. Videos were analyzed by a blinded observer who determined the duration that animals exhibited nocifensive responses. RESULTS Intrathecal or intraperitoneal administration of 1-amino-1-cyclobutanecarboxylic acid reduced the time that animals exhibited nocifensive behaviour, whereas intraplantar administration produced no effect. The effects of intrathecal 1-amino-1-cyclobutanecarboxylic acid were restricted in dermatomal distribution, reversible and produced little or no depression of respiratory rate. An NMDA antagonist blocked antinociception, while mu-opioid or GABAB antagonists did not prevent ACBC antinociception. CONCLUSIONS Intrathecal 1-amino-1-cyclobutanecarboxylic acid in mice produces robust, brief antinociceptive effects with a dermatomal distribution corresponding to the lumbar site of administration. This amino acid merits further exploration as a non-opioid neuraxial analgesic with little or no respiratory side effects. SIGNIFICANCE The novel, non-opioid analgesic, 1-amino-1-cyclobutanecarboxylic acid, produced robust, reversible and localized antinociception in murine models of pain. This study provides evidence supporting further investigation and development of 1-amino-1-cyclobutanecarboxylic acid as a non-opioid spinal analgesic.
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Affiliation(s)
- Timothy Fung
- Hugill Anesthesia Research Centre, Department of Anesthesiology, Pharmacology & Therapeutics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Yahya I Asiri
- Hugill Anesthesia Research Centre, Department of Anesthesiology, Pharmacology & Therapeutics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Kamyar Taheri
- Cannevert Therapeutics Ltd, Vancouver, British Columbia, Canada
| | - Richard Wall
- Hugill Anesthesia Research Centre, Department of Anesthesiology, Pharmacology & Therapeutics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Stephan K W Schwarz
- Hugill Anesthesia Research Centre, Department of Anesthesiology, Pharmacology & Therapeutics, The University of British Columbia, Vancouver, British Columbia, Canada.,Department of Anesthesia, Providence Health Care/St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - Ernest Puil
- Hugill Anesthesia Research Centre, Department of Anesthesiology, Pharmacology & Therapeutics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Bernard A MacLeod
- Hugill Anesthesia Research Centre, Department of Anesthesiology, Pharmacology & Therapeutics, The University of British Columbia, Vancouver, British Columbia, Canada
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Ingle SV, Joshi KA. Exploring Quantum Chemical Descriptors and Molecular Docking Approach for Designing Antagonist Search Model for the Glycine/NMDA Receptor Site. ChemistrySelect 2017. [DOI: 10.1002/slct.201702291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Snehal V. Ingle
- Department of Chemistry; Institute of Chemical Technology, Nathalal Parekh Marg, Matunga; Mumbai 400019 India, Phone/Fax: +91-22-33612614/+91-22-33611020
| | - Kaustubh A. Joshi
- Department of Chemistry; Institute of Chemical Technology, Nathalal Parekh Marg, Matunga; Mumbai 400019 India, Phone/Fax: +91-22-33612614/+91-22-33611020
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Fung T, Asiri YI, Wall R, Schwarz SKW, Puil E, MacLeod BA. Variations of isovaline structure related to activity in the formalin foot assay in mice. Amino Acids 2017; 49:1203-1213. [PMID: 28432424 DOI: 10.1007/s00726-017-2421-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 04/10/2017] [Indexed: 01/25/2023]
Abstract
Current centrally acting analgesics such as opioids are associated with adverse effects that limit their use and threaten patient safety. Isovaline is a novel prototype analgesic that produces peripheral antinociception in several pain models with little or no effect on the central nervous system. The aim of this study was to establish a preliminary structure-activity relationship for isovaline derivatives by assaying efficacy in the formalin foot assay and central adverse effect profile in mice. Selected compounds were tested using the formalin foot assay to determine efficacy in reducing formalin-induced behaviors. Of the compounds tested, R-isovaline, S-isovaline, and 1-amino-1-cyclobutanecarboxylic acid reduced nocifensive behavior in phase II of the assay. These effects occurred without affecting performance on the rotarod, indicating that the reduction in nocifensive behaviors was not due to sedation or motor incoordination. Modifications to isovaline that increased its steric size without a cyclobutane ring formation produced compounds with no activity in the formalin foot assay. These findings indicate that the conformational stability of isovaline or the ability to form a cyclobutane ring is necessary for activity in the formalin foot assay.
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Affiliation(s)
- Timothy Fung
- Department of Anesthesiology, Pharmacology & Therapeutics, Hugill Anesthesia Research Centre, The University of British Columbia, 2176 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Yahya I Asiri
- Department of Anesthesiology, Pharmacology & Therapeutics, Hugill Anesthesia Research Centre, The University of British Columbia, 2176 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Richard Wall
- Department of Anesthesiology, Pharmacology & Therapeutics, Hugill Anesthesia Research Centre, The University of British Columbia, 2176 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Stephan K W Schwarz
- Department of Anesthesiology, Pharmacology & Therapeutics, Hugill Anesthesia Research Centre, The University of British Columbia, 2176 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada.,Department of Anesthesia, Providence Health Care/St. Paul's Hospital, Vancouver, BC, V6Z 1Y6, Canada
| | - Ernest Puil
- Department of Anesthesiology, Pharmacology & Therapeutics, Hugill Anesthesia Research Centre, The University of British Columbia, 2176 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Bernard A MacLeod
- Department of Anesthesiology, Pharmacology & Therapeutics, Hugill Anesthesia Research Centre, The University of British Columbia, 2176 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada.
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Molecular electrostatic potentials in aromatic substituted 4-hydroxyquino-2-lones: glycine/NMDA receptor antagonists. J Mol Model 2008; 15:383-90. [PMID: 19066992 DOI: 10.1007/s00894-008-0411-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Accepted: 07/15/2008] [Indexed: 10/21/2022]
Abstract
Hydroxyquinolone derivatives have proven to be useful for inhibition at the glycine binding site of N-methyl-D-aspartate (NMDA) receptor. In this work the electronic structure, molecular electrostatic potential (MESP) and vibrational characteristics of a set of C(3) substituted 4-hydroxyquino-2-lone (HQ) derivatives, which act as Glycine/NMDA receptor antagonists, have been investigated using the density functional calculations. In the optimized structures a substituent at the C(3) site of HQ tends to adopt a helical structure. MESP investigations reveal that the ligands showing better inhibition activity should possess electron-rich regions extending over the substituent and carbonyl group of HQ. A correlation of inhibitory activity to the molecular electrostatic potential topography at the carbonyl oxygen as well as to the molecular electron density topography turns out to be a significant output of the investigation.
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Inanobe A, Furukawa H, Gouaux E. Mechanism of Partial Agonist Action at the NR1 Subunit of NMDA Receptors. Neuron 2005; 47:71-84. [PMID: 15996549 DOI: 10.1016/j.neuron.2005.05.022] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2004] [Revised: 03/22/2005] [Accepted: 05/20/2005] [Indexed: 11/22/2022]
Abstract
Partial agonists produce submaximal activation of ligand-gated ion channels. To address the question of partial agonist action at the NR1 subunit of the NMDA receptor, we performed crystallographic and electrophysiological studies with 1-aminocyclopropane-1-carboxylic acid (ACPC), 1-aminocyclobutane-1-carboxylic acid (ACBC), and 1-aminocyclopentane-1-carboxylic acid (cycloleucine), three compounds with incrementally larger carbocyclic rings. Whereas ACPC and ACBC partially activate the NMDA receptor by 80% and 42%, respectively, their cocrystal structures of the NR1 ligand binding core show the same degree of domain closure as found in the complex with glycine, a full agonist, illustrating that the NR1 subunit provides a new paradigm for partial agonist action that is distinct from that of the evolutionarily related GluR2, AMPA-sensitive receptor. Cycloleucine behaves as an antagonist and stabilizes an open-cleft conformation. The NR1-cycloleucine complex forms a dimer that is similar to the GluR2 dimer, thereby suggesting a conserved mode of subunit-subunit interaction in AMPA and NMDA receptors.
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MESH Headings
- Amino Acids, Cyclic/pharmacology
- Animals
- Binding, Competitive/drug effects
- Crystallography, X-Ray
- Cycloleucine/pharmacology
- Electrophysiology
- Excitatory Amino Acid Agonists/pharmacology
- Female
- Kinetics
- Ligands
- Models, Molecular
- Mutation
- Oocytes/metabolism
- Patch-Clamp Techniques
- Protein Conformation
- Rats
- Receptors, AMPA/metabolism
- Receptors, Glycine/drug effects
- Receptors, Glycine/metabolism
- Receptors, N-Methyl-D-Aspartate/agonists
- Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors
- Receptors, N-Methyl-D-Aspartate/genetics
- Xenopus
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Affiliation(s)
- Atsushi Inanobe
- Department of Biochemistry and Molecular Biophysics, Columbia University, 650 West 168th Street, New York, NY 10032, USA
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Karcz-Kubicha M, Jessa M, Nazar M, Plaznik A, Hartmann S, Parsons CG, Danysz W. Anxiolytic activity of glycine-B antagonists and partial agonists--no relation to intrinsic activity in the patch clamp. Neuropharmacology 1997; 36:1355-67. [PMID: 9423923 DOI: 10.1016/s0028-3908(97)00130-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
On the basis of animal models, anxiety was one of the first suggested clinical applications of partial agonists of the glycineB site coupled to the NMDA receptor. It is not certain, however, whether these findings can be extended to full glycineB antagonists and what is the relation between intrinsic activity (degree of NMDA receptor antagonism) and anxiolytic effect. In the present study several NMDA receptor antagonists, including several glycineB antagonists/partial agonists, were tested for anxiolytic activity in the Vogel conflict test and the elevated plus-maze. Additionally, the intrinsic activities of the glycineB partial agonists used [ACPC, (R,+)-HA-966 and D-cycloserine] were compared in patch-clamp experiments in cultured neurones. In the plus-maze the most striking increase in the time spent in open arms (index of anxiolytic effect) was seen after diazepam and D-cycloserine (at doses that did not change locomotion). Also reliable (dose-dependent), although weaker, anxiolytic activity was produced by the uncompetitive NMDA receptor antagonist (+)MK-801 and the competitive antagonist CGP 39551. Modest anxiolytic-like effect in the plus-maze was also observed after the glycineB antagonist L-701,324 and the partial agonist (+,R)-HA-966. Uncompetitive antagonists memantine and amantadine, the glycineB partial agonist ACPC (up to 600 mg/kg) or the full antagonists MRZ 2/570, MRZ 2/571 and MRZ 2/576 had no effect. In the Vogel conflict test neither memantine, nor any of the full glycineB antagonists tested (L-701,324 and MRZ 2/576), showed anxiolytic activity. Patch-clamp studies revealed that the intrinsic activity of (+,R)-HA-966, D-cycloserine and ACPC was 13, 57 and 92%, respectively, as compared to that of glycine itself (100%). In conclusion, for the agents tested there is no clear relation between the levels of intrinsic activity, i.e. degree of NMDA receptor inhibition, and anxiolytic activity. Moreover, L-701,324 and MRZ-type glycineB full antagonists do not exchibit anxiolytic activity in the elevated plus-maze and Vogel conflict test.
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Affiliation(s)
- M Karcz-Kubicha
- Department of Pharmacology, Merz & Co., Frankfurt am Main, Germany
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Rao SN, Chan MF, Balaji VN. Conformational Studies Using Molecular Mechanics on Model Peptides with 1-Aminocycloalkane 1-Carboxylic Acid Residues. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1997. [DOI: 10.1246/bcsj.70.293] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Bisaga A, Krzascik P, Jankowska E, Palejko W, Kostowski W, Danysz W. Effect of glutamate receptor antagonists on N-methyl-D-aspartate- and (S)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-induced convulsant effects in mice and rats. Eur J Pharmacol 1993; 242:213-20. [PMID: 7506658 DOI: 10.1016/0014-2999(93)90244-c] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Selected antagonists of N-methyl-D-aspartate (NMDA) and (S)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonists, acting through different recognition sites were studied in three in vivo experimental procedures: systemic administration of NMDA or AMPA to mice and 7-day-old rats or i.c.v. injection in adult rats. Antagonists were given i.p. before the agonists. Of the substances tested (+)-5-methyl-10,11- dihydro-5H-dibenzocyclohepten-5,10-imine maleate ((+)-MK-801, an uncompetitive NMDA receptor antagonist) and DL-(E)-2-amino-4-methyl-5- phosphono-3-pentanoic acid (CGP-37849, a competitive NMDA receptor antagonist) were the most potent and selective NMDA receptor antagonists, having ED50s below 1 mg/kg in all three tests. 1-Amino-3,5-dimethyladamantane (memantine, an uncompetitive NMDA receptor antagonist) was less potent and, additionally, inhibited AMPA-induced seizures in adult rats. Aminocyclopropane carboxylic acid--a partial agonist at the glycine site coupled to NMDA receptors (GlyB)--was a weak antagonist (ED50 > 150 mg/kg) in mice. Other partial GlyB receptor agonists, aminocyclobutane carboxylic acid, (+,R)-3-amino-1-hydroxy-2-pyrrolidine ((+,R)-HA-966) and d-cycloserine, and antagonists, 5,7-dinitroquinoxaline-2,3-dione (MNQX) and 5,7-dichlorokynurenic acid, were ineffective in mice after systemic administration. The last two agents however were active in adult rats when given i.c.v. Thus affinity, intrinsic activity (GlyB receptor partial agonists) and/or penetration into the brain (GlyB receptor antagonists) seem to be important factors in determining the effectiveness of these agents.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- A Bisaga
- Department of Pharmacology, Institute of Psychiatry and Neurology, Warsaw, Poland
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Yoneda Y, Suzuki T, Ogita K, Han D. Support for radiolabeling of a glycine recognition domain on the N-methyl-D-aspartate receptor ionophore complex by 5,7-[3H]dichlorokynurenate in rat brain. J Neurochem 1993; 60:634-45. [PMID: 8419541 DOI: 10.1111/j.1471-4159.1993.tb03195.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Pretreatment with Triton X-100 more than doubled the binding of radiolabeled 5,7-dichlorokynurenic acid (DCKA), a proposed antagonist at a glycine (Gly) recognition domain on the N-methyl-D-aspartate (NMDA) receptor ionophore complex, in rat brain synaptic membranes. The binding exhibited an inverse temperature dependency, reversibility, and saturability, the binding sites consisting of a single component with a high affinity (27.5 nM) and a relatively low density (2.87 pmol/mg of protein). The binding of both [3H]DCKA and [3H]Gly was similarly displaced by numerous putative agonists and antagonists at the Gly domain in a concentration-dependent manner at a concentration range of 100 nM to 0.1 mM. Among the 24 putative ligands tested, DCKA was the second most potent displacer of the binding of both radioligands with no intrinsic affinity for the binding of [3H]kainic acid and alpha-amino-3-hydroxy-5- [3H]methylisoxazole-4-propionic acid (AMPA) to the non-NMDA receptors. In contrast, the other proposed potent Gly antagonist, 5,7-dinitroquinoxaline-2,3-dione, was active in displacing the binding of [3H]glutamic ([3H]Glu) and D,L-(E)-2-amino-4-[3H]propyl-5-phosphono-3-pentenoic acids to the NMDA recognition domain with a relatively high affinity for the non-NMDA receptors. In addition, the proposed antagonist at the AMPA-sensitive receptor, 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(F)quinoxaline, not only displaced weakly the binding of both [3H]-Gly and [3H]DCKA, but also inhibited the binding of (+)-5-[3H]methyl-10,11- dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine ([3H]MK-801) to an ion channel associated with the NMDA-sensitive receptor in the presence of added Glu alone in a manner sensitive to antagonism by further added Gly. Clear correlations were seen between potencies of the displacers to displace [3H]DCKA binding and [3H]Gly binding, in addition to between the potencies to displace [3H]-DCKA or [3H]Gly binding and to potentiate or inhibit [3H]MK-801 binding. All quinoxalines tested were invariably more potent displacers of [3H]DCKA binding than [3H]Gly binding, whereas kynurenines were similarly effective in displacing the binding of both [3H]Gly and [3H]DCKA. These results undoubtedly give support to the proposal that [3H]DCKA is one useful radioligand available in terms of its high selectivity and affinity for the Gly domain in the brain. Possible multiplicity of the Gly domain is suggested by the differential pharmacological profiles between the binding of [3H]Gly and [3H]DCKA.
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Affiliation(s)
- Y Yoneda
- Department of Pharmacology, Setsunan University, Osaka, Japan
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Lawlor BA, Davis KL. Does modulation of glutamatergic function represent a viable therapeutic strategy in Alzheimer's disease? Biol Psychiatry 1992; 31:337-50. [PMID: 1348429 DOI: 10.1016/0006-3223(92)90227-q] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Although glutamate dysfunction has been implicated in the pathogenesis of Alzheimer's disease (AD), it is unclear which direction a glutamatergic strategy should take in this illness. Increasing glutamate function may enhance excitotoxicity and neuronal death, whereas decreasing activity in this excitatory amino acid pathway may impair memory processes. Pharmacological modulation of the different NMDA and nonNMDA receptor sites, together with the concept of an agonist versus antagonist approach, are discussed in this review. It would appear that a glutamatergic approach may represent a new and exciting option to pursue in the experimental pharmacotherapeutics of AD.
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Affiliation(s)
- B A Lawlor
- Department of Psychiatry, Mount Sinai School of Medicine, New York, NY
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Abstract
The N-methyl-D-aspartic acid (NMDA)-sensitive subclass of brain excitatory amino acid receptors is supposed to be a receptor-ionophore complex consisting of at least 3 different major domains including an NMDA recognition site, glycine (Gly) recognition site and ion channel site. Biochemical labeling of the NMDA domain using [3H]L-glutamic acid (Glu) as a radioactive ligand often meets with several critical methodological pitfalls and artifacts that cause a serious misinterpretation of the results. Treatment of brain synaptic membranes with a low concentration of Triton X-100 induces a marked disclosure of [3H]Glu binding sensitive to displacement by NMDA with a concomitant removal of other several membranous constituents with relatively high affinity for the neuroactive amino acid. The NMDA site is also radiolabeled by the competitive antagonist (+/-)-3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid that reveals possible heterogeneity of the site. The Gly domain is sensitive to D-serine and D-alanine but insensitive to strychnine, and this domain seems to be absolutely required for an opening of the NMDA channels by agonists. The ionophore domain is radiolabeled by a non-competitive type of NMDA antagonist that is only able to bind to the open but not closed channels. The binding of these allosteric antagonists is markedly potentiated by NMDA agonists in a manner sensitive to antagonism by isosteric antagonists in brain synaptic membranes and additionally enhanced by further inclusion of Gly agonists through the Gly domain. Furthermore, physiological and biochemical responses mediated by the NMDA receptor complex are invariably potentiated by several endogenous polyamines, suggesting a novel polyamine site within the complex. At any rate, activation of the NMDA receptor complex results in a marked influx of Ca2+ as well as Na+ ions, which subsequently induces numerous intracellular metabolic alterations that could be associated with neuronal plasticity or excitotoxicity. Therefore, any isosteric and allosteric antagonists would be of great benefit for the therapy and treatment of neurodegenerative disorders with a risk of impairing the acquisition and formation process of memories.
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Affiliation(s)
- Y Yoneda
- Department of Pharmacology, Setsunan University, Hirakata, Osaka, Japan
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14
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Procter AW, Stratmann GC, Francis PT, Lowe SL, Bertolucci PH, Bowen DM. Characterisation of the glycine modulatory site of the N-methyl-D-aspartate receptor-ionophore complex in human brain. J Neurochem 1991; 56:299-310. [PMID: 1670955 DOI: 10.1111/j.1471-4159.1991.tb02596.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
[3H]Glycine binding and glycine modulation of [3H]MK-801 binding have been used to study the glycine allosteric site associated with the N-methyl-D-aspartate receptor complex in postmortem human brain. The effect of glycine on [3H]MK-801 binding appeared sensitive to duration of terminal coma, and possibly postmortem delay. Thirty percent of the binding occurred in a subfraction of brain tissue and did not show enhancement by glycine and glutamic acid. [3H]Glycine binding to a subfraction free from this component was studied and showed high specific binding. KD and Bmax values showed considerable intersubject variability which did not appear to be due to demographic features or to tissue content of amino acids with an affinity for this site. The pharmacological characteristics of binding in this subfraction and a correlation between Bmax values and the maximal enhancement of [3H]MK-801 binding by glycine are consistent with [3H]glycine binding occurring to an N-methyl-D-aspartate receptor complex associated site. Further support for this is provided by a significantly lower Bmax value for [3H]glycine binding in subjects with Alzheimer's disease and reduced glycine enhancement of [3H]MK-801 binding. However, the effect of perimortem factors makes it difficult to confidently attribute this solely to a disease-related change in the receptor. The possible role of the glycine allosteric site in the treatment of neuropsychiatric disorders is discussed.
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Affiliation(s)
- A W Procter
- Miriam Marks Department of Neurochemistry, UMDS-Guy's Hospital Campus, London, England
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15
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Chapter 2. Recent Advances In Excitatory Amino Acid Research. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 1991. [DOI: 10.1016/s0065-7743(08)61189-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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16
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Monahan JB, Hood WF, Compton RP, Cordi AA, Williams RM. Identification of a novel structural class of positive modulators of the N-methyl-D-aspartate receptor, with actions mediated through the glycine recognition site. Eur J Pharmacol 1990; 189:373-9. [PMID: 1963601 DOI: 10.1016/0922-4106(90)90034-u] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
This study describes a new structural class of compounds which interact at the N-methyl-D-aspartate (NMDA) receptor-associated glycine recognition site. These E-gamma-substituted vinylglycine derivatives were active in displacing [3H]glycine binding from the NMDA receptor-associated recognition site in rat forebrain synaptic plasma membranes, with Ki values in the range of 0.24-8.7 microM. Functional analyses of these compounds indicate that they positively modulate basal [3H](+)-5-methyl-10,11-dihydro-5H- [a,d]cyclohepaten-5,10-imine ([3H]MK-801) binding, consistent with their having agonist characteristics. Little stereospecificity is observed with the gamma-substituted methyl and propyl derivatives while the L-isomer of the hexyl analog is significantly more potent than the D-isomer. The D- and L-hydroxyethyl gamma-substituted vinylglycines were the most potent inhibitors of [3H]glycine binding with Ki values of 0.75 +/- 0.06 microM and 0.24 +/- 0.02 microM, respectively. The 3,4-double bond was necessary for activity in that the saturated hexyl derivative (2-aminodecanoate) was inactive. Based on the results reported herein, the hypothesis that there is a distinct size restriction for functional agonists which interact with the glycine recognition site, should be altered to include these larger extensions of vinylglycine.
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Affiliation(s)
- J B Monahan
- Searle Research and Development, Division of G.D. Searle & Co., St. Louis, MO 63198
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17
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Lanthorn TH, Hood WF, Watson GB, Compton RP, Rader RK, Gaoni Y, Monahan JB. Cis-2,4-methanoglutamate is a potent and selective N-methyl-D-aspartate receptor agonist. Eur J Pharmacol 1990; 182:397-404. [PMID: 2146136 DOI: 10.1016/0014-2999(90)90036-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cis- and trans-2,4-methanoglutamate were compared with L-glutamate as acidic amino acid ligands. Cis-2,4-methanoglutamate had a Ki of 0.052 microM against N-methyl-D-aspartate (NMDA)-specific L-[3H]glutamate binding compared with 0.050 microM for L-glutamate. Cis-2,4-methanoglutamate exhibited no significant affinity against [3H]kainate or [3H]alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate ([3H]AMPA) binding. Trans-2,4-methanoglutamate had no significant affinity for any of these sites. Cis-2,4-methanoglutamate increased [3H]N-1[2-thienyl]cyclohexyl-3,4-piperidine [( 3H]TCP) binding with EC50 of 0.35 +/- 0.14 microM. It produced an inward current in rat brain mRNA-injected Xenopus oocytes which was blocked by the NMDA antagonist, D-2-amino-7-phosphonoheptanoate (D-AP7). Cis-2,4-methanoglutamate (EC50 = 15.9 microM) was 100-fold more potent than L-glutamate (EC50 = 1,584 microM) in reducing the excitatory postsynaptic potential in CA1 of hippocampal slices. Cis-2,4-methanoglutamate is the most potent, selective NMDA agonist known.
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Affiliation(s)
- T H Lanthorn
- CNS Diseases Research, G.D. Searle & Co., St. Louis, MO
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18
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Watson GB, Monaghan DT, Lanthorn TH. Selective activation of oscillatory currents by trans-ACPD in rat brain mRNA-injected Xenopus oocytes and their blockade by NMDA. Eur J Pharmacol 1990; 179:479-81. [PMID: 1694771 DOI: 10.1016/0014-2999(90)90194-b] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- G B Watson
- CNS Diseases Research, G.D. Searle & Company, Chesterfield, MO 63198
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19
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Rao TS, Cler JA, Compton RP, Emmett MR, Mick S, Sun ET, Iyengar S, Wood PL. Neuropharmacological characterization of 1-aminocyclopropane-1-carboxylate and 1-aminocyclobutane-1-carboxylate, ligands of the N-methyl-D-aspartate-associated glycine receptor. Neuropharmacology 1990; 29:305-9. [PMID: 2158004 DOI: 10.1016/0028-3908(90)90018-m] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Following intravenous administration, 1-aminocyclobutane-1-carboxylate (ACBC, 100 mg/kg), a N-methyl-D-aspartate (NMDA)-associated glycine receptor antagonist, was eliminated with a T1/2 of 5 min in mouse brain and 4 min in rat cerebrospinal fluid (CSF). 1-Aminocyclopropane-1-carboxylate (ACC), a NMDA-associated glycine receptor agonist, was found to have a T1/2 of less than 5 min in mouse brain. ACC and ACBC did not alter basal cerebellar cGMP. Glycine and D-serine increased cGMP, and 1-hydroxy-3-aminopyrrolidone-2 (HA-966), a glycine antagonist, reversed the D-serine-induced increases in cGMP. In contrast, ACBC did not reverse the D-serine-induced increases in cGMP. These data suggest that despite their brain bioavailability and marked potency at the glycine receptor in vitro, ACC and ACBC are rapidly inactivated and thus have limited in vivo utility.
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Affiliation(s)
- T S Rao
- CNS Diseases Research, G. D. Searle & Company, St. Louis, MO 63198
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20
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Watson GB, Bolanowski MA, Baganoff MP, Deppeler CL, Lanthorn TH. D-cycloserine acts as a partial agonist at the glycine modulatory site of the NMDA receptor expressed in Xenopus oocytes. Brain Res 1990; 510:158-60. [PMID: 2157524 DOI: 10.1016/0006-8993(90)90745-w] [Citation(s) in RCA: 127] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In the Xenopus oocyte preparation, D-cycloserine (DCS) had the profile of a partial agonist at the glycine modulatory site of the NMDA receptor. Maximal NMDA responses in the presence of DCS were only 40-50% of those in the presence of glycine. Glycine and D-serine were agonists at this site. The actions of DCS were competitively antagonized by HA-966, a known glycine antagonist.
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Affiliation(s)
- G B Watson
- CNS Diseases Research, G.D. Searle & Company St. Louis, MO 63198
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21
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Wood PL, Rao TS, Iyengar S, Lanthorn T, Monahan J, Cordi A, Sun E, Vazquez M, Gray N, Contreras P. A review of the in vitro and in vivo neurochemical characterization of the NMDA/PCP/glycine/ion channel receptor macrocomplex. Neurochem Res 1990; 15:217-30. [PMID: 2159127 DOI: 10.1007/bf00972212] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- P L Wood
- CNS Disease Research, G.D. Searle & Co., Monsanto Co., St. Louis, MO 63198
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22
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Compton RP, Hood WF, Monahan JB. Evidence for a functional coupling of the NMDA and glycine recognition sites in synaptic plasma membranes. Eur J Pharmacol 1990; 188:63-70. [PMID: 2155123 DOI: 10.1016/0922-4106(90)90248-v] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Activation of the N-methyl-D-aspartate (NMDA) receptor complex is subject to modulation via interactions at a coupled [3H]glycine recognition site in rat brain synaptic plasma membranes (SPM). We examined the effect of the potent and specific glycine site antagonists, 1-hydroxy-3-amino-2-pyrrolidone (HA-966) and 1-aminocyclobutane-1-carboxylate (ACBC), on the NMDA recognition site. These glycine analogs were found to significantly stimulate the binding of the competitive NMDA antagonist, [3H]3-(2-carboxypiperazin-4-y1)propyl-1-phosphonate ([3H]CPP) in a dose-dependent fashion, whereas both compounds inhibited NMDA-specific L-[3H]glutamate (agonist) binding. Additionally, both glycine antagonists reduced the binding of [3H]1-[1-(2-thienyl)cyclohexyl]piperidine ([3H]TCP) to SPM, a functional assessment of activation of the NMDA receptor-channel complex. The glycine site agonists, glycine and serine reversed these effects in a dose-dependent manner, with the serine reversal being stereospecific for D-serine. The relative potencies of these compounds in reversing the glycine antagonist effects on the NMDA recognition site corresponded with their ability to competitively displace strychnine-insensitive [3H]glycine binding. These results provide evidence for a functional coupling between the glycine and NMDA recognition sites and further, may provide a mechanism by which compounds interacting at the glycine recognition site may modulate NMDA receptor activity.
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Affiliation(s)
- R P Compton
- CNS Diseases Research, G. D. Searle and Company, St. Louis, MO 63198
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23
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Leonard JP, Kelso SR. Apparent desensitization of NMDA responses in Xenopus oocytes involves calcium-dependent chloride current. Neuron 1990; 4:53-60. [PMID: 1690016 DOI: 10.1016/0896-6273(90)90443-j] [Citation(s) in RCA: 108] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
N-Methyl-D-aspartate (NMDA) receptors were expressed and studied in Xenopus oocytes injected with rat brain RNA. NMDA application elicits a rapid inward current that decays in several seconds to a relatively stable level. This decay is reportedly due to desensitization. However, we found the early transient component could be evoked more than once during a single application of NMDA, suggesting that the receptor did not actually desensitize. Removal of external Ca2+, replacement of Ca2+ with Ba2+, or intracellular injection of EGTA abolished the transient component. Furthermore, a variety of Cl- channel blockers nearly eliminated the transient component and inhibited the plateau current as well. We propose that a significant portion of the NMDA current recorded in oocytes is carried by a transient inward Cl- current triggered by Ca2+ influx through the NMDA receptor/channel.
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Affiliation(s)
- J P Leonard
- Department of Biological Sciences, University of Illinois, Chicago 60607
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