Glycine and kynurenate modulate the glutamate receptors in the myenteric plexus and in cortical membranes.
The responses evoked by stimulation of the N-methyl-D-aspartate receptors in the guinea-pig myenteric plexus were potentiated by micromolar concentrations of glycine and were non-competitively antagonized by kynurenate (IC50: 60 microM). The effects of kynurenate were competitively prevented by glycine. Furthermore, kynurenate displaced [3H]glycine from its binding sites on rat cortical membranes (IC50: 20 microM). Kynurenate and glycine, therefore, probably act at the same site, evoking opposite effects on the function of the ion channel complex of the N-methyl-D-aspartate receptor.
Moroni
F
F
Department of Preclinical and Clinical Pharmacology, Mario Aiazzi Mancini, University of Florence, Italy.
Pellegrini-Giampietro
D E
DE
Alesiani
M
M
Cherici
G
G
Mori
F
F
Galli
A
A
D015763:2-Amino-5-phosphonovalerate; D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D005998:Glycine / Q000494:pharmacology*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007736:Kynurenic Acid / Q000494:pharmacology*; D009197:Myenteric Plexus / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017470:Receptors, Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter / Q000378:metabolism*; D014633:Valine / Q000031:analogs & derivatives / Q000494:pharmacology
D000927:Anticonvulsants; D017470:Receptors, Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter; D015763:2-Amino-5-phosphonovalerate; D007736:Kynurenic Acid; D014633:Valine; D005998:Glycine