Dietary flavonoid quercetin stimulates vasorelaxation in aortic vessels.
Considerable epidemiological evidence indicates that dietary consumption of moderate levels of polyphenols decreases both the incidence of cardiovascular disease and the mortality associated with myocardial infarction. Molecular mechanisms of this cardiovascular protection remain uncertain but can involve changes in rates of nitric oxide (NO) generation by endothelial nitric oxide synthase (eNOS). We examined the vascular responses to quercetin using a combination of biochemical and vessel function criteria. Quercetin treatment for 30min enhanced relaxation of rat aortic ring segments. Moreover, the addition of L-NAME (100muM) or charybdotoxin (ChTx) blocked quercetin-mediated vasorelaxation thus demonstrating the effect was partially dependent on NOS and endothelium-derived hyperpolarizing factor (EDHF). Additionally, bovine aortic endothelial cells (BAEC) treated with quercetin showed a rapid increase of intracellular Ca(2+) concentrations as well as a dose- and time-dependent stimulation of eNOS phosphorylation with a concomitant increase in NO production. These results demonstrate that quercetin-mediated stimulation of eNOS phosphorylation increases NO bioavailability in endothelial cells and can thus play a role in the vascular protective effects associated with improved endothelial cell function.
Khoo
Nicholas K H
NK
Department of Anesthesiology, The University of Alabama at Birmingham, Birmingham, AL 35294-2172, USA. nkhoo@pitt.edu
White
C Roger
CR
Pozzo-Miller
Lucas
L
Zhou
Fen
F
Constance
Chad
C
Inoue
Takafumi
T
Patel
Rakesh P
RP
Parks
Dale A
DA
D000818:Animals; D001011:Aorta / Q000187:drug effects* / Q000502:physiology; D001685:Biological Factors / Q000502:physiology; D002417:Cattle; D018999:Charybdotoxin / Q000494:pharmacology; D006152:Cyclic GMP / Q000378:metabolism*; D004032:Diet; D004730:Endothelium, Vascular / Q000187:drug effects; D066298:In Vitro Techniques; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010766:Phosphorylation; D011794:Quercetin / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014664:Vasodilation / Q000187:drug effects*
D001685:Biological Factors; C067410:endothelium-dependent hyperpolarization factor; D018999:Charybdotoxin; D011794:Quercetin; D052250:Nitric Oxide Synthase Type III; D006152:Cyclic GMP; D019331:NG-Nitroarginine Methyl Ester