TY - JOUR T1 - Identification and Characterization of Novel NMDA Receptor Antagonists Selective for NR2A- over NR2B-Containing Receptors JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 636 LP - 644 DO - 10.1124/jpet.110.172544 VL - 335 IS - 3 AU - Ezio Bettini AU - Anna Sava AU - Cristiana Griffante AU - Corrado Carignani AU - Alberto Buson AU - Anna Maria Capelli AU - Michele Negri AU - Filippo Andreetta AU - Sergio A. Senar-Sancho AU - Lorena Guiral AU - Francesca Cardullo Y1 - 2010/12/01 UR - http://jpet.aspetjournals.org/content/335/3/636.abstract N2 - NR1/NR2A is a subtype of N-methyl-d-aspartate receptors (NMDARs), which are glutamate and glycine-gated Ca2+-permeable channels highly expressed in the central nervous system. A high-throughput screening (HTS) campaign using human osteosarcoma (U-2 OS) cells transiently transduced with NR1/NR2A NMDAR subunits, tested in a specifically designed fluorometric imaging plate reader (FLIPR)/Ca2+ assay, identified sulfonamide derivative series, exemplified by 3-chloro-4-fluoro-N-[(4-{[2-(phenylcarbonyl)hydrazino]carbonyl}phenyl)methyl]benzenesulfonamide (compound 1) and thiodiazole derivative N-(cyclohexylmethyl)-2-({5-[(phenylmethyl)amino]-1,3,4-thiadiazol-2-yl}thio)acetamide (compound 13) as novel NR1/NR2A receptor antagonists. Compounds 1 and 13 displayed submicromolar and micromolar potency at NR1/NR2A receptor, respectively, although they did not show activity at NR2B-containing receptor up to 50 μM concentration. Addition of 1 mM glycine, but not 1 mM l-glutamate, was able to surmount compound 1 and 13 inhibitory effects in FLIPR NR1/NR2A assay. However, compounds 1 and 13 displaced a glutamate site antagonist [3H]d,l-(E)-2-amino-4-propyl-5-phosphono-3-pentenoic acid ([3H]CGP 39653) to a greater extent than the glycine site antagonist [3H]3-[(E)-2-carboxy-2-phenylethenyl]-4,6-dichloro-1H-indole-2-carboxylic acid ([3H]MDL 105,519), in rat brain cortex binding assay. Results of FLIPR cell-based, electrophysiological, and biochemical binding assays suggest that compounds 1 and 13 are the prototypes of novel classes of NMDAR ligands, which to the best of our knowledge are the first selective antagonists at NR1/NR2A over NR1/NR2B receptor, and might constitute useful tools able to elucidate the relative role of the NR2A subunit in physiological and pathological conditions. ER -