Abstract
Quinolinic acid (QA) induced clonic and tonic convulsions in mice when it was injected into the cerebral ventricle. Pretreatment with L-arginine (L-Arg), a substrate of nitric oxide (NO) synthase (NOS), and/or 5,6,7,8-tetrahydrobiopterin (THB), cofactor of NOS, tended to potentiate QA-induced convulsion. NG-monomethyl-L-arginine (NMMA), a competitive NOS inhibitor, diminished QA-induced convulsion. This effect of NMMA was attenuated by coadministration of L-Arg or THB. Sodium nitroprusside (SNP), which spontaneously releases NO, did not potentiate, but diminished QA-induced convulsion. These findings suggest that an endogenous NO may be involved, at least in part, in QA-induced convulsion in mice, and that an exogenous NO released from SNP may cause downregulation of N-methyl-D-aspartate (NMDA) receptor activity, and thereby prevent the excessive excitation of NMDA receptors and subsequent convulsion caused by QA.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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2-Amino-5-phosphonovalerate* / analogs & derivatives*
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Amino Acids / pharmacology
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Animals
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Anticonvulsants / pharmacology
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Arginine / analogs & derivatives
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Arginine / pharmacology
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Biopterins / analogs & derivatives
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Biopterins / pharmacology
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Dizocilpine Maleate / pharmacology
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Dose-Response Relationship, Drug
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Injections, Intraventricular
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Kynurenic Acid / analogs & derivatives
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Kynurenic Acid / pharmacology
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Male
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Mice
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Mice, Inbred Strains
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Nitric Oxide / antagonists & inhibitors
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Nitric Oxide / physiology*
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Nitroprusside / pharmacology
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Piperazines / pharmacology
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Quinolinic Acid* / administration & dosage
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Receptors, N-Methyl-D-Aspartate / antagonists & inhibitors
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Seizures / chemically induced
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Seizures / physiopathology*
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omega-N-Methylarginine
Substances
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Amino Acids
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Anticonvulsants
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Piperazines
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Receptors, N-Methyl-D-Aspartate
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Nitroprusside
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Biopterins
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omega-N-Methylarginine
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Nitric Oxide
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Dizocilpine Maleate
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2-Amino-5-phosphonovalerate
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Arginine
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3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid
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sapropterin
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Quinolinic Acid
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Kynurenic Acid
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2-amino-7-phosphonoheptanoic acid
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7-chlorokynurenic acid