Vasorelaxant effect of quercetin on cerebral basilar artery in vitro and the underlying mechanisms study

Abstract

The aim of this study is to investigate the vasorelaxant effect of quercetin on cerebral basilar artery in vitro and provide a preliminary discussion concerning the underlying mechanisms. Using a DMT-isolated micro vessel system, quercetin was found to exhibit a vasodilatory effect on basilar arteries contracted by potassium chloride (KCl), endothelin-1 (ET-1), and 5-hydroxytryptamine (5-HT). The vasorelaxant effect of quercetin was partially attenuated when endothelium cells were removed. L-NAME, indomethacin, and ODQ treatment also decreased the potency of quercetin. In endothelium-denuded rings, the vasorelaxant effect of quercetin was not influenced by K channel inhibitors. However, quercetin inhibited KCl induced extracellular calcium influx and ET-1 induced transient intracellular calcium release in a Ca-free solution. In conclusion, quercetin induced relaxation of the basilar artery in vitro is partially dependent on endothelium, which is mainly related to NO and COX pathways. It also induces relaxation through blockage of calcium channels.

Polyphenolic compounds of Euphorbia umbellata (Pax) Bruyns (Euphorbiaceae) improved endothelial dysfunction through arginase inhibition

“…However, this would not be sufficient to explain the pattern of relaxation obtained ex vivo (138%). These observations endorse the hypothesis that quercetin exhibits a vasodilator potential that is partially mediated by the endothelium through endotheliumderived NO (Yuan et al, 2018), since in conductance vessels (aorta) vascular reactivity relies almost entirely on the endothelial release of NO (Sánchez et al, 2006). This is supported, at least in part, by the well-known antioxidant properties of the polyphenolic compounds with protective actions regarding the bioavailability of NO.…”

“…This is supported, at least in part, by the well‐known antioxidant properties of the polyphenolic compounds with protective actions regarding the bioavailability of NO. It has also been recognised that quercetin leads to a reduction in the release of constrictive factors such as thromboxane A 2 , and also it might be involved in the cyclooxygenase‐prostacyclin signalling pathway in an endothelium‐dependent fashion, which can contribute to the relaxation effect that was observed (Duarte et al, 2002; Yuan et al, 2018).…”

The Effect of Dietary Polyphenols on Vascular Health and Hypertension: Current Evidence and Mechanisms of Action

“…Flavonoids, such as anthocyanins [ 65 , 66 ], flavones (i.e., luteolin) [ 67 ], flavanones (i.e., naringin) [ 68 ], flavan-3-ols (i.e., epicatechin) [ 69 ], flavonols (i.e., kaempferol) [ 70 ] and isoflavones [ 71 ], and resveratrol [ 72 , 73 ] may play a direct role in improving the bioavailability in the bloodstream of NO by increasing the activation of inducible NO synthase (iNOS) and endothelial NO synthase (eNOS) provided by modulation of signal transduction, for instance through the phosphatidylinositol 3-kinase (PI3K)/Akt or the adenosine monophosphate-activated protein kinase (AMPK) pathways [ 67 ]. Together with other polyphenols, such as caffeic acid [ 74 ], kaempferol [ 75 ], quercetin [ 76 ], luteolin [ 77 ], and biochanin A [ 78 ], these compounds may exert vasorelaxing effects also by acting on vascular smooth muscle cells directly (through activation of BK channels or inhibition of Ca 2+ channels) or indirectly (through activation of Ca 2+ -activated K + channels in endothelial cells, leading to hyperpolarization and inhibition of Ca 2+ influx to vascular smooth muscle cells), eventually limiting construction and leading to vasorelaxation [ 79 ]. However, some polyphenols, such as resveratrol, have been shown to act through more than one of the aforementioned mechanisms [ 80 ].…”

Quercetin Exerts Age-Dependent Beneficial Effects on Blood Pressure and Vascular Function, But Is Inefficient in Preventing Myocardial Ischemia-Reperfusion Injury in Zucker Diabetic Fatty Rats

“…Antihypertensive effect of QCT has been documented also in woman with diabetes type 2 [29] and obese Zucker rats [30]. In addition to blood pressure-lowering effects, QCT has been shown to exert vasorelaxant effects [31][32][33][34] as well as endothelium-protective and anti-atherosclerotic effects [35] in different experimental models, including direct vasoprotective effects in isolated aortas from streptozotocin-induced diabetic rats [36][37][38]. However, effects of QCT on vascular reactivity in diabetes type 2 have still to be explored.…”