Potentiation of synaptic reflexes by D-serine in the rat spinal cord in vitro.
6-Cyano-7-nitroquinoxaline-2,3-dione (CNQX) (10 microM) depressed dorsal root-evoked ventral and dorsal root potentials of the in vitro immature rat spinal cord to 26.3 +/- 5.2 S.E.M. and 40.8 +/- 2.7% of control values respectively. These depressant effects of CNQX were partially reversed by D-serine (EC50 values 39.7 microM +/- 8.7 S.E.M. N = 6 and 34.9 +/- 12.5 microM, N = 5 for ventral root potential and dorsal root potential respectively). Under our experimental conditions, which included the presence of Mg2+ (0.75 mM) in the bathing medium, no measurable potentiation of these synaptic reflexes by D-serine was recorded in the absence of CNQX. These data indicate that CNQX, in addition to its depressant effect at non-NMDA receptors, depresses an NMDA receptor-mediated component of segmental transmission through its action at the glycine site of the NMDA receptor complex.
Siarey
R J
RJ
DUPHAR B.V., Weesp, The Netherlands.
Long
S K
SK
Evans
R H
RH
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D000818:Animals; D000831:Animals, Newborn; D066298:In Vitro Techniques; D008274:Magnesium / Q000494:pharmacology; D011810:Quinoxalines / Q000037:antagonists & inhibitors / Q000494:pharmacology; D012018:Reflex / Q000187:drug effects*; D012694:Serine / Q000008:administration & dosage / Q000494:pharmacology*; D013116:Spinal Cord / Q000187:drug effects*; D013569:Synapses / Q000187:drug effects*; D009435:Synaptic Transmission / Q000187:drug effects
D011810:Quinoxalines; D012694:Serine; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D008274:Magnesium