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Modulation of striatal quinolinate neurotoxicity by elevation of endogenous brain kynurenic acid.
Br J Pharmacol. 1998 May; 124(2):391-9.BJ

Abstract

1. Nicotinylalanine, an inhibitor of kynurenine metabolism, has been shown to elevate brain levels of endogenous kynurenic acid, an excitatory amino acid receptor antagonist. This study examined the potential of nicotinylalanine to influence excitotoxic damage to striatal NADPH diaphorase (NADPH-d) and gamma-aminobutyric acid (GABA)ergic neurones that are selectively lost in Huntington's disease. 2. A unilateral injection of the N-methyl-D-aspartate (NMDA) receptor agonist, quinolinic acid, into the rat striatum produced an 88% depletion of NADPH-d neurones. Intrastriatal infusion of quinolinic acid also produced a dose-dependent reduction in striatal GABA content. 3. Nicotinylalanine (2.3, 3.2, 4.6, 6.4 nmol 5 microl(-1), i.c.v.) administered with L-kynurenine (450 mg kg(-1)), a precursor of kynurenic acid, and probenecid (200 mg kg(-1)), an inhibitor of organic acid transport, 3 h before the injection of quinolinic acid (15 nmol) produced a dose-related attenuation of the quinolinic acid-induced loss of NADPH-d neurones. Nicotinylalanine (5.6 nmol 5 microl(-1)) in combination with L-kynurenine and probenecid also attenuated quinolinic acid-induced reductions in striatal GABA content. 4. Nicotinylalanine (4.6 nmol, i.c.v.), L-kynurenine alone or L-kynurenine administered with probenecid did not attenuate quinolinic acid-induced depletion of striatal NADPH-d neurones. However, combined administration of kynurenine and probenecid did prevent quinolinic acid-induced reductions in ipsilateral striatal GABA content. 5. Injection of nicotinylalanine, at doses (4.6 nmol and 5.6 nmol i.c.v.) which attenuated quinolinic acid-induced striatal neurotoxicity, when combined with L-kynurenine and probenecid produced increases in both whole brain and striatal kynurenic acid levels. Administration of L-kynurenine and probenecid without nicotinylalanine also elevated kynurenic acid, but to a lesser extent. 6. The results of this study demonstrate that nicotinylalanine has the potential to attenuate quinolinic acid-induced striatal neurotoxicity. It is suggested that nicotinylalanine exerts its effect by increasing levels of endogenous kynurenic acid in the brain. The results of this study suggest that agents which influence levels of endogenous excitatory amino acid antagonists such as kynurenic acid may be useful in preventing excitotoxic damage to neurones in the CNS.

Authors+Show Affiliations

Department of Pharmacology and Toxicology, Queen's University, Kingston, Ontario, Canada.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

9641558

Citation

Harris, C A., et al. "Modulation of Striatal Quinolinate Neurotoxicity By Elevation of Endogenous Brain Kynurenic Acid." British Journal of Pharmacology, vol. 124, no. 2, 1998, pp. 391-9.
Harris CA, Miranda AF, Tanguay JJ, et al. Modulation of striatal quinolinate neurotoxicity by elevation of endogenous brain kynurenic acid. Br J Pharmacol. 1998;124(2):391-9.
Harris, C. A., Miranda, A. F., Tanguay, J. J., Boegman, R. J., Beninger, R. J., & Jhamandas, K. (1998). Modulation of striatal quinolinate neurotoxicity by elevation of endogenous brain kynurenic acid. British Journal of Pharmacology, 124(2), 391-9.
Harris CA, et al. Modulation of Striatal Quinolinate Neurotoxicity By Elevation of Endogenous Brain Kynurenic Acid. Br J Pharmacol. 1998;124(2):391-9. PubMed PMID: 9641558.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Modulation of striatal quinolinate neurotoxicity by elevation of endogenous brain kynurenic acid. AU - Harris,C A, AU - Miranda,A F, AU - Tanguay,J J, AU - Boegman,R J, AU - Beninger,R J, AU - Jhamandas,K, PY - 1998/6/26/pubmed PY - 1998/6/26/medline PY - 1998/6/26/entrez SP - 391 EP - 9 JF - British journal of pharmacology JO - Br J Pharmacol VL - 124 IS - 2 N2 - 1. Nicotinylalanine, an inhibitor of kynurenine metabolism, has been shown to elevate brain levels of endogenous kynurenic acid, an excitatory amino acid receptor antagonist. This study examined the potential of nicotinylalanine to influence excitotoxic damage to striatal NADPH diaphorase (NADPH-d) and gamma-aminobutyric acid (GABA)ergic neurones that are selectively lost in Huntington's disease. 2. A unilateral injection of the N-methyl-D-aspartate (NMDA) receptor agonist, quinolinic acid, into the rat striatum produced an 88% depletion of NADPH-d neurones. Intrastriatal infusion of quinolinic acid also produced a dose-dependent reduction in striatal GABA content. 3. Nicotinylalanine (2.3, 3.2, 4.6, 6.4 nmol 5 microl(-1), i.c.v.) administered with L-kynurenine (450 mg kg(-1)), a precursor of kynurenic acid, and probenecid (200 mg kg(-1)), an inhibitor of organic acid transport, 3 h before the injection of quinolinic acid (15 nmol) produced a dose-related attenuation of the quinolinic acid-induced loss of NADPH-d neurones. Nicotinylalanine (5.6 nmol 5 microl(-1)) in combination with L-kynurenine and probenecid also attenuated quinolinic acid-induced reductions in striatal GABA content. 4. Nicotinylalanine (4.6 nmol, i.c.v.), L-kynurenine alone or L-kynurenine administered with probenecid did not attenuate quinolinic acid-induced depletion of striatal NADPH-d neurones. However, combined administration of kynurenine and probenecid did prevent quinolinic acid-induced reductions in ipsilateral striatal GABA content. 5. Injection of nicotinylalanine, at doses (4.6 nmol and 5.6 nmol i.c.v.) which attenuated quinolinic acid-induced striatal neurotoxicity, when combined with L-kynurenine and probenecid produced increases in both whole brain and striatal kynurenic acid levels. Administration of L-kynurenine and probenecid without nicotinylalanine also elevated kynurenic acid, but to a lesser extent. 6. The results of this study demonstrate that nicotinylalanine has the potential to attenuate quinolinic acid-induced striatal neurotoxicity. It is suggested that nicotinylalanine exerts its effect by increasing levels of endogenous kynurenic acid in the brain. The results of this study suggest that agents which influence levels of endogenous excitatory amino acid antagonists such as kynurenic acid may be useful in preventing excitotoxic damage to neurones in the CNS. SN - 0007-1188 UR - https://www.unboundmedicine.com/medline/citation/9641558/Modulation_of_striatal_quinolinate_neurotoxicity_by_elevation_of_endogenous_brain_kynurenic_acid_ L2 - https://doi.org/10.1038/sj.bjp.0701834 DB - PRIME DP - Unbound Medicine ER -