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BioMed Research International
Volume 2014 (2014), Article ID 247054, 7 pages
http://dx.doi.org/10.1155/2014/247054
Research Article

Endothelium-Independent Vasorelaxant Effects of Hydroalcoholic Extract from Nigella sativa Seed in Rat Aorta: The Roles of Ca2+ and K+ Channels

1Cardiovascular Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad 9177948564, Iran
2Department of Physiology, School of Medicine, Mashhad University of Medical Sciences, Mashhad 9177948564, Iran
3Neurogenic Inflammation Research Centre, School of Medicine, Mashhad University of Medical Sciences, Mashhad 9177948564, Iran

Received 4 February 2014; Revised 13 April 2014; Accepted 21 April 2014; Published 12 May 2014

Academic Editor: Karim Bendjelid

Copyright © 2014 Saeed Niazmand 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

Objective. The aim of this study was to elucidate the mechanism(s) responsible for the vasorelaxant effect of Nigella sativa (N. sativa). Methods. The activity of different concentrations of N. sativa extract was evaluated on contractile responses of isolated aorta to KCl and phenylephrine (PE). Results. The extract (2–14 mg/mL) induced a concentration dependent relaxation both in endothelium-intact and endothelium-denuded aortic rings precontracted by PE (10−6 M) and KCl (6 × 10−2 M). Extract reduced PE- and KCl-induced contractions in presence of cumulative concentrations of calcium (10−5–10−2 M) significantly. L-NAME and indomethacin had no effect on vasorelaxation effect of extract in PE-induced contraction. Diltiazem and heparin reduced significantly this vasorelaxation at a concentration of 14 mg/mL of extract; however, N. sativa-induced relaxation was not affected by ruthenium red. Tetraethylammonium chloride reduced the extract-induced relaxation in concentrations of 2–6 mg/mL of extract significantly but glibenclamide reduced this relaxative effect in all concentrations of extract. Conclusions. The inhibitory effect of N. sativa seed extract on the contraction induced by PE and KCl was endothelium-independent. This relaxation was mediated mainly through the inhibition of Ca2+ and channels and also intracellular calcium release.