Open AccessEffects of the Novel Tricyclic Quinoxalinedione Derivatives, SM-18400 and Its Analogs, on N-Methyl-D-aspartate (NMDA) Receptor-Mediated Synaptic Transmission in the Isolated Neonatal Rat Spinal Cord In Vitro
Author(s) -
Yoshimi Maruoka,
Yukihiro Ohno,
Hiroyasu Tanaka,
H Yasuda,
Kenichi Otani,
Chika Tamamura,
Mitsutaka Nakamura
Publication year - 1998
Publication title -
japanese journal of pharmacology/japanese journal of pharmacology
Language(s) - English
Resource type - Journals
eISSN - 1347-3506
pISSN - 0021-5198
DOI - 10.1254/jjp.76.265
Subject(s) - nmda receptor , glycine receptor , glycine , agonist , neurotransmission , chemistry , tricyclic , pharmacology , receptor , inhibitory postsynaptic potential , spinal cord , stereochemistry , biochemistry , biology , amino acid , endocrinology , neuroscience
We examined the effects of novel tricyclic quinoxalinedione derivatives, SM-18400 ((S)-9-chloro-5-[p-aminomethyl-o-(carboxymethoxy)phenylcarbamoylmethy l]-6,7-dihydro-1H,5H-pyrido[1,2,3-de]quinoxaline-2,3-dione hydrochloride trihydrate) and its analogs (i.e., ID-17263 and ID-17332), on the N-methyl-D-aspartate (NMDA) receptor-mediated polysynaptic reflex (PSR) in the isolated spinal cord of neonatal rats in vitro. Application of SM-18400 selectively suppressed the PSR activity in a concentration-dependent manner without affecting the monosynaptic reflex (MSR). Differential suppression of the PSR was also obtained with ID-17263, ID-17332 and other known NMDA receptor glycine-binding site antagonists, 5,7-dichlorokynurenate (5,7-diClkyn) and L-689,560 (4-trans-2-carboxy-5,7-dichloro-4-phenylaminocarbonylamino-1,2,3,4 -tetrahydroquinoline). Relative potencies of the test drugs for inhibition of the PSR were as follows: SM-18400 >> L-689,560 > ID-17332 > ID-17263 > 5,7-diClkyn. In addition, the inhibitory effects of SM-18400 on PSR were markedly antagonized by simultaneous application of D-serine, an agonist for NMDA receptor glycine-binding sites. These findings suggest that SM-18400 is a potent NMDA receptor glycine-binding site antagonist and blocks the NMDA receptor-mediated synaptic neurotransmission in the spinal cord in vitro.