Document Type: Original Research Article
Department of heart, School of Medicine, Gorgan University of Medical Sciences, Gorgan, Iran
Department of Physiology, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Department of Pharmacology, School of Pharmacy, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Objective: In a previous work, we showed that asafoetida essential oil (AEO), from oleo-gum resin of Ferula asafoetida L. from the Apiaceae family, has a vasodilatory effect. This effect was both endothelium-dependent and endothelium-independent. The present study was designed to determine whether potassium channels and intracellular calcium release contribute to AEO-induced vasodilation.
Materials and Methods: Rats' thoracic aorta were isolated and denuded. Following induction of contraction by potassium chloride (60 mM), concentration-response curve was plotted by the cumulative addition of AEO (0.625-80 µl/l to the medium of rings. The vasodilatory effect of AEO was assessed before and after addition of phenylephrine and potassium channel blockers (including barium chloride (BC), 4-aminopyridine (4A) and glibenclamide (Gl)).
Results: AEO relaxed the precontracted rings in a concentration-dependent manner (IC50=23 µl/l). All potassium channel blockers significantly attenuated the vasodilatory activity of AEO when they were added to rings medium before addition of KCl (p<0.01, 4A and Gl groups and p< 0.001, BC group vs. control group) but not after that. In contrast to K channel blockers, adding AEO before or after phenylephrine, the tension was reduced significantly (p<0.05 vs. the control group).
Conclusion: The findings of this study indicated that the vasodilatory effect of AEO on denuded-endothelium aortic ring was mediated through activation of potassium channels and reduced intracellular calcium release.