The effect of calcium blocker activity on vasorelaxant of Nigella sativa extract on rat isolated aorta

Background: Nigella sativa (NS) is a plant that has been used as a natural remedy for number of illnesses such as headache, bronchitis, exema and influenza. NS has also been studied for its pharmacologic effects such as anti-diabetic, anti-inflammatory, anti-oxidant, anti-microbial and anti-cancer activities. There are some reports of cardiovascular effects of NS such as hypotensive and also negative inotropic effects. The aim of this study was to
investigate the activity of calcium channels on vasorelaxant extract of NS on isolated rat aorta.
Methods: In this experimental study, 28 male Wistar rats randomly divided into 4 groups (n= 7). In groups 1 and 2 the effect of the extract (5, 10 and 20 mg/ml) on contracted aorta by PE, (10- 6 M) in intact and denuded endothelium were investigated. In groups 3 the effect of the extract on contracted aorta by PE in thepresence of Diltiazem (Dil), (10-5 M) and In group 4 the effect of the extract on contracted aorta by PE in the presence of Heparin
(Hep), (50 mg/ml) were investigated. Statistical analysis was carried out by SPSS software version 13 and the results were analyzed by student t-test and ANOVA.
Results: The extract significantly relaxed the contracted aorta by PE in both intact and denuded endothelium in concentration dependent manner (P<0.001 ،P=0.002). All the extract concentrations significantly relaxed PE induced contraction in the presence of Dil and Hep (P<0.001, P<0.01).
Conclusion: The extract of NS have the relaxation effect on vascular smooth muscle. It seems, the relaxation was mediated by inhibition of voltage-and receptor-dependent Ca+2channels and may partly by inhibition the release of calcium from intracellular
stores in vascular smooth muscle cells.