title: Endothelium-dependent vasodilation effects ofPanax notoginsengand its main components are mediated by nitric oxide and cyclooxygenase pathways.
abstract: Panax notoginseng, a traditional Chinese herbal medicine, has been used for the treatment of cardiovascular diseases. The main bioactive components of this species arePanax notoginsengsaponins (PNS). The present study aimed to investigate the effects of PNS and five of its main components (ginsenosides Rg1, Re, Rb1 and Rd, and notoginsenoside R1) on rat aorta rings pre-contracted with norepinephrine (NE) and to determine the underlying mechanism of action. Isolated aorta rings (with or without intact endothelium) from adult male Wistar rats were stimulated with NE to induce vasoconstriction, and subsequently treated with different concentrations of PNS and its five main components (Rg1, Re, Rb1, R1 and Rd) separately. This procedure was repeated after pre-incubation with the nitric oxide (NO) synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME), the guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) and the cyclooxygenase (COX) inhibitor indomethacin (INDO), in order to elucidate the mechanism of action of PNS and its components. The results demonstrated that PNS and the components Rg1, Re, Rb1 and R1, but not Rd, induced vessel relaxation in a concentration-dependent manner when the endothelium lining was intact. NO synthase inhibitor L-NAME and guanylate cyclase inhibitor ODQ attenuated the diastolic effects of PNS, Rg1, Re, Rb1 and R1 in aortic rings with intact endothelium. By contrast, INDO, a known COX inhibitor weakened the vasodilation effects of PNS, Re and Rb1 but demonstrated no effect on Rg1 and R1. In conclusion, PNS and two of its main components (Re and Rb1) exert vasodilating effects through the NO and COX pathways.
authors.affiliation: Institute of Traditional Chinese Medicine Research, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China; Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin Medical University, Tianjin 300070, P.R. China.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Institute of Traditional Chinese Medicine Research, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China; Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin Medical University, Tianjin 300070, P.R. China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Ren
authors.affiliation: Institute of Traditional Chinese Medicine Research, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China; Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin Medical University, Tianjin 300070, P.R. China.
authors.forename: Leilei
authors.initials: L
authors.lastname: Xing
authors.affiliation: Institute of Traditional Chinese Medicine Research, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China; Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin Medical University, Tianjin 300070, P.R. China.
authors.forename: Xiangdong
authors.initials: X
authors.lastname: Dai
authors.affiliation: Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin 300070, P.R. China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Liu
authors.affiliation: Institute of Traditional Chinese Medicine Research, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China; Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin Medical University, Tianjin 300070, P.R. China.
authors.forename: Bin
authors.initials: B
authors.lastname: Yu
authors.affiliation: Institute of Traditional Chinese Medicine Research, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China; Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin Medical University, Tianjin 300070, P.R. China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
keywords: Panax notoginseng saponins; aortic ring; cyclooxygenase; ginsenoside Rb1; ginsenoside Rd; ginsenoside Re; ginsenoside Rg1; nitric oxide; notoginsenoside R1