Document Type : Original Article
PHYSIOLOGY DEPARTMENT, MEDICAL SCIENCES SCHOOL, MEDICINE IRAN UNIVERSITY, TEHRAN, IRAN
Introduction: Garlic is considered to be one of the best diseaseتpreventive foods because of its potent and widespread effects. On the other hand, some cardiovascular disorders including hypertension are accompanied with altered responsiveness of vascular alpha-adrenergic receptors. The purpose of this study was to investigate the effect of aqueousgarlic extract on alpha1-adrenoceptor agonist-induced contraction of rat aorta, aorta ring from rats pretreated with aqueousgarlic extract were used as a model in this study.
Materials and Methods: Four and eight weeks after treatment with garlic extract, aortic rings were studied for contractile and relaxation response to phenylephrine (PE) and acetylcholine, respectively. Results: The results showed that the contractile response of aortic rings to PE in garlic treated rats for 4 and 8 weeks decreased (P<0.05), and their endothelium-dependent relaxation response increased in comparison with the controls (P<0.05). The relaxing activity of garlic on rat aorta was time-dependent and this effect was attenuated following endothelium removal.
Conclusion: These data suggest that alpha1-adrenoceptor antagonistic action of garlic on rat aorta involves at least two different mechanisms: one is direct relaxing action of garlic on smooth muscle, and the other is indirect and dependent on garlic effect onalpha1-adrenoceptors signal transduction cascade.