Abstract
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.
MeSH terms
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2-Amino-5-phosphonovalerate
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Animals
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Anticonvulsants / pharmacology
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Cerebral Cortex / drug effects
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Cerebral Cortex / metabolism*
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Glycine / pharmacology*
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Guinea Pigs
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In Vitro Techniques
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Kynurenic Acid / pharmacology*
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Myenteric Plexus / drug effects
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Myenteric Plexus / metabolism*
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Rats
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Receptors, Glutamate
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Receptors, N-Methyl-D-Aspartate
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Receptors, Neurotransmitter / metabolism*
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Valine / analogs & derivatives
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Valine / pharmacology
Substances
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Anticonvulsants
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Receptors, Glutamate
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Receptors, N-Methyl-D-Aspartate
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Receptors, Neurotransmitter
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2-Amino-5-phosphonovalerate
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Kynurenic Acid
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Valine
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Glycine