Effect of 7-chloro kynurenic acid on glycine modulation of the N-methyl-D-aspartate response in guinea-pig myenteric plexus.
The glycine modulation of the N-methyl-D-aspartate (NMDA) response in guinea-pig myenteric plexus was investigated by using D-serine and 7-chloro kynurenic acid as a glycine agonist and antagonist, respectively. D-serine caused a concentration-dependent enhancement of the NMDA response, an effect which was competitively inhibited by 7-chloro kynurenic acid (pA2 = 6.0). In addition, 7-chloro kynurenic acid induced a concentration-dependent, non-competitive inhibition of the NMDA response per se, even in the absence of added D-serine. This inhibition was fully reversed by exogenous D-serine, suggesting that this effect was also due to the occupancy of the glycine site. These results emphasize the usefulness of the guinea-pig myenteric plexus for studying the function of the NMDA receptor complex.
Reggiani
A
A
Glaxo Research Laboratories, Verona, Italy.
Maraia
G
G
Ceserani
R
R
Gaviraghi
G
G
D000818:Animals; D001224:Aspartic Acid / Q000494:pharmacology; D005998:Glycine / Q000037:antagonists & inhibitors* / Q000502:physiology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007736:Kynurenic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D008297:Male; D009197:Myenteric Plexus / Q000187:drug effects*; D016202:N-Methylaspartate; D012694:Serine / Q000494:pharmacology
D001224:Aspartic Acid; D012694:Serine; D016202:N-Methylaspartate; D007736:Kynurenic Acid; C057013:7-chlorokynurenic acid; D005998:Glycine