title: Synthesis, binding affinity at glutamic acid receptors, neuroprotective effects, and molecular modeling investigation of novel dihydroisoxazole amino acids.
abstract: The four stereoisomers of 5-(2-amino-2-carboxyethyl)-4,5-dihydroisoxazole-3-carboxylic acid(+)-4, (-)-4, (+)-5, and (-)-5 were prepared by stereoselective synthesis of two pairs of enantiomers, which were subsequently resolved by enzymatic procedures. These four stereoisomers and the four stereoisomers of the bicyclic analogue 5-amino-4,5,6,6a-tetrahydro-3aH-cyclopenta[d]isoxazole-3,5-dicarboxylic acid (+)-2, (-)-2, (+)-3, and (-)-3 were tested at ionotropic and metabotropic glutamate receptor subtypes. The most potent NMDA receptor antagonists [(+)-2, (-)-4, and (+)-5] showed a significant neuroprotective effect when tested in an oxygen glucose deprivation (OGD) cell culture test. The same compounds were preliminarily assayed using Xenopus oocytes expressing cloned rat NMDA receptors containing the NR1 subunit in combination with either NR2A, NR2B, NR2C, or NR2D subunit. In this assay, all three derivatives showed high antagonist potency with preference for the NR2A and NR2B subtypes, with derivative (-)-4 behaving as the most potent antagonist. The biological data are discussed on the basis of homology models reported in the literature for NMDA receptors and mGluRs.
authors.affiliation: Istituto di Chimica Farmaceutica e Tossicologica, Università degli Studi di Milano, Viale Abruzzi 42, 20131 Milano, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Conti
authors.forename: Marco
authors.initials: M
authors.lastname: De Amici
authors.forename: Giovanni
authors.initials: G
authors.lastname: Grazioso
authors.forename: Gabriella
authors.initials: G
authors.lastname: Roda
authors.forename: Andrea
authors.initials: A
authors.lastname: Pinto
authors.forename: Kasper Bø
authors.initials: KB
authors.lastname: Hansen
authors.forename: Birgitte
authors.initials: B
authors.lastname: Nielsen
authors.forename: Ulf
authors.initials: U
authors.lastname: Madsen
authors.forename: Hans
authors.initials: H
authors.lastname: Bräuner-Osborne
authors.forename: Jan
authors.initials: J
authors.lastname: Egebjerg
authors.forename: Valentina
authors.initials: V
authors.lastname: Vestri
authors.forename: Domenico E
authors.initials: DE
authors.lastname: Pellegrini-Giampietro
authors.forename: Pauline
authors.initials: P
authors.lastname: Sibille
authors.forename: Francine C
authors.initials: FC
authors.lastname: Acher
authors.forename: Carlo
authors.initials: C
authors.lastname: De Micheli
mesh_terms: D000596:Amino Acids / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D001665:Binding Sites; D016466:CHO Cells; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D005260:Female; D066298:In Vitro Techniques; D007555:Isoxazoles / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D051379:Mice; D008958:Models, Molecular; D018696:Neuroprotective Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D009865:Oocytes / Q000187:drug effects / Q000502:physiology; D018408:Patch-Clamp Techniques; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011869:Radioligand Assay; D051381:Rats; D017470:Receptors, Glutamate / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D018094:Receptors, Metabotropic Glutamate / Q000819:agonists / Q000737:chemistry / Q000235:genetics; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics; D015290:Second Messenger Systems / Q000187:drug effects; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D014982:Xenopus laevis
chemical_list: D000596:Amino Acids; D007555:Isoxazoles; C120997:NR2A NMDA receptor; D018696:Neuroprotective Agents; D021122:Protein Subunits; D017470:Receptors, Glutamate; D018094:Receptors, Metabotropic Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; C108822:metabotropic glutamate receptor 2