Effects of Ginkgo biloba extract on blood pressure and vascular endothelial response by acetylcholine in spontaneously hypertensive rats
- 18 February 2006
- journal article
- Published by Oxford University Press (OUP) in Journal of Pharmacy and Pharmacology
- Vol. 58 (2), 243-249
- https://doi.org/10.1211/jpp.58.2.0012
Abstract
We previously demonstrated that Ginkgo biloba extract (Ginkgo) produced vasodilation via the nitric oxide pathway in aortic segments isolated from Wistar rats. In this study, we have analysed the effects of daily long‐term oral Ginkgo treatment on blood pressure, vascular tone, and calcium mobilization to evaluate the clinical availability. Spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY) were fed either a control diet or a diet containing 0.05%–0.5% Ginkgo for 30 days. Administration of Ginkgo did not change systolic blood pressure in WKY, but significantly decreased systolic blood pressure in SHR. In thoracic aortic preparations isolated from SHR, diminished relaxation in response to acetylcholine was improved by a Ginkgo‐containing diet. This diet significantly decreased the EC50 value and significantly increased maximum relaxation in response to acetylcholine in SHR. In aortic segments isolated from WKY, acetylcholine‐induced relaxation was not affected by a Ginkgo‐containing diet. Sodium nitroprusside‐induced relaxation was unchanged by a Ginkgo‐containing diet in SHR and WKY. We also examined the effects of a Ginkgo‐containing diet on the intracellular calcium level of aortic endothelium using a fluorescent confocal microscopic imaging system. Calcium Green 1/AM preloading indicated that acetylcholine significantly increased the endothelial intracellular calcium level. The Ginkgo‐containing diet significantly enhanced this increase in the aortic endothelium of SHR, but did not change that of WKY. The results suggested that Ginkgo enhanced endothelium‐dependent vasodilation and elevation of the endothelial intracellular Ca2+ level in SHR, resulting in hypotension. This accelerative effect of Ginkgo on Ca2+ mobilization seemed to be associated with restoration of impaired dilatory function induced by acetylcholine in endothelial cells.Keywords
This publication has 27 references indexed in Scilit:
- Reactive Oxygen Species in the VasculatureHypertension, 2003
- Effects of the Flavonoid Quercetin and its Methylated Metabolite Isorhamnetin in Isolated Arteries from Spontaneously Hypertensive RatsPlanta Medica, 2003
- Herbal RemediesNew England Journal of Medicine, 2002
- Antihypertensive effects of the flavonoid quercetin in spontaneously hypertensive ratsBritish Journal of Pharmacology, 2001
- Cardioprotective and Anti-oxidant Effects of the Terpenoid Constituents ofGinkgo bilobaExtract (EGb 761)Journal of Molecular and Cellular Cardiology, 1997
- Effects of natural antioxidant Ginkgo biloba extract (EGB 761) on myocardial ischemia-reperfusion injuryFree Radical Biology & Medicine, 1994
- Ginkgo bilobaThe Lancet, 1992
- Flavonoids are scavengers of superoxide anionsBiochemical Pharmacology, 1988
- Calcium and Activation of the Release of Endothelium‐Derived Relaxing FactorAnnals of the New York Academy of Sciences, 1988
- Involvement of platelet-activating factor (PAF) in cerebral post-ischemic phase in Mongolian gerbilsProstaglandins, 1987