[3H]5,7-dichlorokynurenic acid recognizes two binding sites in rat cerebral cortex membranes.
J Recept Signal Transduct Res
; 18(2-3): 91-112, 1998.
Article
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| MEDLINE
| ID: mdl-9651880
Binding of [3H]5,7-dichlorokynurenic acid ([3H]DCKA), a competitive antagonist of the strychnine-insensitive glycine site of the N-methyl-D-aspartate (NMDA) receptor channel complex, was characterized in synaptic plasma membranes from rat cerebral cortex. Non linear curve fitting of [3H]DCKA saturation and homologous displacement isotherms indicated the existence of two binding sites: a specific, saturable, high affinity site, with a pKD value of 7.24 (KD = 57.5 nmol/l) and a maximum binding value (Bmax) of 6.9 pmol/mg of protein and a second site, with micromolar affinity. The pharmacological profile of both binding components was determined by studying the effect on [3H]DCKA and [3H]glycine binding of a series of compounds known to interact with different excitatory and inhibitory amino acid receptors. These studies confirmed the identity of the high affinity site of [3H]DCKA binding with the strychnine-insensitive glycine site of the NMDA receptor channel complex. 3-[2-(Phenylaminocarbonyl)ethenyl]-4,6-dichloroindole-2-carb oxylic acid sodium salt (GV 150526A), a new, high affinity, selective glycine site antagonist (1), was the most potent inhibitor of this component of binding (pKi = 8.24, Ki = 5.6 nmol/l). The low affinity component of [3H]DCKA binding was insensitive to the agonists glycine and D-serine and the partial agonist (+/-)-3-amino-1-hydroxy-2-pyrrolidone (HA 966), though recognised by glycine site antagonists. The precise nature of this second, low affinity [3H]DCKA binding site remains to be elucidated.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Corteza Cerebral
/
Receptores de N-Metil-D-Aspartato
/
Receptores de Glicina
/
Antagonistas de Aminoácidos Excitadores
/
Ácido Quinurénico
Límite:
Animals
Idioma:
En
Revista:
J Recept Signal Transduct Res
Asunto de la revista:
BIOQUIMICA
/
FISIOLOGIA
Año:
1998
Tipo del documento:
Article
País de afiliación:
Italia
Pais de publicación:
Reino Unido