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BioMed Research International
Volume 2013 (2013), Article ID 530603, 8 pages
http://dx.doi.org/10.1155/2013/530603
Research Article

Modulation of Vasodilator Response via the Nitric Oxide Pathway after Acute Methyl Mercury Chloride Exposure in Rats

1School of Sciences, Indira Gandhi National Open University, New Delhi 110068, India
2Department of Physiology, V.P. Chest Institute, University of Delhi, New Delhi 110007, India
3Jamia Hamdard University, New Delhi 110062, India

Received 29 April 2013; Revised 14 June 2013; Accepted 13 July 2013

Academic Editor: M. Firoze Khan

Copyright © 2013 S. Omanwar et al. 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

Mercury exposure induces endothelial dysfunction leading to loss of endothelium-dependent vasorelaxation due to decreased nitric oxide (NO) bioavailability via increased oxidative stress. Our aim was to investigate whether acute treatment with methyl mercury chloride changes the endothelium-dependent vasodilator response and to explore the possible mechanisms behind the observed effects. Wistar rats were treated with methyl mercury chloride (5 mg/kg, po.). The methyl mercury chloride treatment resulted in an increased aortic vasorelaxant response to acetylcholine (ACh). In methyl-mercury-chloride-exposed rats, the % change in vasorelaxant response of ACh in presence of Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME;  M) was significantly increased, and in presence of glybenclamide (  M), the response was similar to that of untreated rats, indicating the involvement of NO and not of endothelium-derived hyperpolarizing factor (EDHF). In addition, superoxide dismutase (SOD) + catalase treatment increased the NO modulation of vasodilator response in methyl-mercury-chloride-exposed rats. Our results demonstrate an increase in the vascular reactivity to ACh in aorta of rats acutely exposed to methyl mercury chloride. Methyl mercury chloride induces nitric oxide synthase (NOS) and increases the NO production along with inducing oxidative stress without affecting the EDHF pathway.