The reduction of arterial tension produced by stevioside is dependent on nitric oxide synthase activity when the endothelium is intact

Abstract

Original T h e r e d u c t i o n o f a r t e r i a l t e n s i o n p r o d u c e d b AbstractIn endothelium-intact rat aortic ring preparations pre-contracted with norepinephrine or KCl, N G -nitro L-arginine (L-NOARG, 0.1 mM) and 1H-[1,2,4] oxidiazolo [4,3-a] quinoxalin-1-one (ODQ, 10 µM) antagonized the reduction of the vascular tone induced by stevioside, but this antagonism did not occur when the experiment was performed with endothelium-denuded aortic rings. The data indicates that the vasodilatation produced by stevioside is dependent on nitric oxide synthase and guanylate cyclase activities when the endothelium is not damaged.

Electrophysiological, Vasoactive, and Gastromodulatory Effects of Stevia in Healthy Wistar Rats

“…and endothelium-denuded tissues [20]. Nitric oxide synthase acts as a key mediator in stevia-induced vasorelaxation when the endothelium is intact, since pretreatment of the aorta with N G -nitro L-arginine (L-NAME) diminished the relaxation caused by stevia [20].…”

“…Nitric oxide synthase acts as a key mediator in stevia-induced vasorelaxation when the endothelium is intact, since pretreatment of the aorta with N G -nitro L-arginine (L-NAME) diminished the relaxation caused by stevia [20]. In endothelium-denuded aortic preparations, the suggested dilatory mechanism of stevia may be through the blockade of Ca 2+ channels [20]. In addition to vasodilatation, stevia reduced gastric mucosal damage induced by histamine in rainbow trout [21].…”

“…However, Wong et al (2004) indicated that the release of nitric oxide (NO) might not be the mechanism of action of stevia for aortic relaxation [29]. Interestingly, stevia was capable of relaxing aortic tissue both with and without endothelium, precontracted with either noradrenaline or potassium chloride [20]. This would indicate that in large vessels, part of the relaxation mechanisms of stevia is via the NO synthase/guanylate cyclase pathway, which only works when the endothelium is present.…”