Int. J. Mol. Sci. 2013, 14(11), 21328-21338; doi:10.3390/ijms141121328

Quinolinic Acid: Neurotoxin or Oxidative Stress Modulator?

1email, 2email and 1,* email
Received: 2 September 2013; in revised form: 2 October 2013 / Accepted: 22 October 2013 / Published: 25 October 2013
(This article belongs to the collection Molecular Research in Neurotoxicology)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: Quinolinic acid (2,3-pyridinedicarboxylic acid, QUIN) is a well-known neurotoxin. Consequently, QUIN could produce reactive oxygen species (ROS). ROS are generated in reactions catalyzed by transition metals, especially iron (Fe). QUIN can form coordination complexes with iron. A combination of differential pulse voltammetry, deoxyribose degradation and Fe(II) autoxidation assays was used for explorating ROS formation in redox reactions that are catalyzed by iron in QUIN-Fe complexes. Differential pulse voltammetry showed an anodic shift of the iron redox potential if iron was liganded by QUIN. In the H2O2/FeCl3/ascorbic acid variant of the deoxyribose degradation assay, the dose-response curve was U-shaped. In the FeCl3/ascorbic acid variant, QUIN unambiguously showed antioxidant effects. In the Fe(II) autoxidation assay, QUIN decreased the rate of ROS production caused by Fe(II) oxidation. Our study confirms that QUIN toxicity may be caused by ROS generation via the Fenton reaction. This, however, applies only for unnaturally high concentrations that were used in attempts to provide support for the neurotoxic effect. In lower concentrations, we show that by liganding iron, QUIN affects the Fe(II)/Fe(III) ratios that are beneficial to homeostasis. Our results support the notion that redox chemistry can contribute to explaining the hormetic dose-response effects.
Keywords: differential pulse voltammetry; Fenton reaction; hormesis; hydroxyl radical; inflammation; iron autoxidation; kynurenines; neuropathology; neurotoxicants; oxidative stress
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MDPI and ACS Style

Kubicova, L.; Hadacek, F.; Chobot, V. Quinolinic Acid: Neurotoxin or Oxidative Stress Modulator? Int. J. Mol. Sci. 2013, 14, 21328-21338.

AMA Style

Kubicova L, Hadacek F, Chobot V. Quinolinic Acid: Neurotoxin or Oxidative Stress Modulator? International Journal of Molecular Sciences. 2013; 14(11):21328-21338.

Chicago/Turabian Style

Kubicova, Lenka; Hadacek, Franz; Chobot, Vladimir. 2013. "Quinolinic Acid: Neurotoxin or Oxidative Stress Modulator?" Int. J. Mol. Sci. 14, no. 11: 21328-21338.

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