Tetrazolyl isoxazole amino acids as ionotropic glutamate receptor antagonists: Synthesis, modelling and molecular pharmacology

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• 作者：Bente Frø ; lund ; Jeremy R. Greenwood ; Mai M. Holm ; Jan Egebjerg ; Ulf Madsen ; Birgitte Nielsen ; Hans Brä ; uner-Osborne ; Tine B. Stensbø ; l and Povl Krogsgaard-Larsen
• 关键词：Ionotropic Glu receptors ; Antagonists ; AMOA ; Tetrazole group
• 刊名：Bioorganic and Medicinal Chemistry
• 出版年：2005
• 期刊代码：9_09680896
• 类别：ch
• 出版时间：2005
• 卷：13
• 期：18
• 页码：5391-5398
• 文件大小：901 K

摘要

Two 3-(5-tetrazolylmethoxy) analogues, 1a and 1b, of (RS)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA), a selective AMPA receptor agonist, and (RS)-2-amino-3-(5-tert-butyl-3-hydroxy-4-isoxazolyl)propionic acid (ATPA), a GluR5-preferring agonist, were synthesized. Compounds 1a and 1b were pharmacologically characterized in receptor binding assays, and electrophysiologically on homomeric AMPA receptors (GluR1-4), homomeric (GluR5 and GluR6) and heteromeric (GluR6/KA2) kainic acid receptors, using two-electrode voltage-clamped Xenopus laevis oocytes expressing these receptors. Both analogues proved to be antagonists at all AMPA receptor subtypes, showing potencies (K_b = 38–161 μM) similar to that of the AMPA receptor antagonist (RS)-2-amino-3-[3-(carboxymethoxy)-5-methyl-4-isoxazolyl]propionic acid (AMOA) (K_b = 43–76 μM). Furthermore, the AMOA analogue, 1a, blocked two kainic acid receptor subtypes (GluR5 and GluR6/KA2), showing sevenfold preference for GluR6/KA2 (K_b = 19 μM). Unlike the iGluR antagonist (S)-2-amino-3-[5-tert-butyl-3-(phosphonomethoxy)-4-isoxazolyl]propionic acid [(S)-ATPO], the corresponding tetrazolyl analogue, 1b, lacks kainic acid receptor effects. On the basis of docking to a crystal structure of the isolated extracellular ligand-binding core of the AMPA receptor subunit GluR2 and a homology model of the kainic acid receptor subunit GluR5, we were able to rationalize the observed structure–activity relationships.