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Effect of whole wild blueberries on endothelium‐dependent (ED) vasodilation in spontaneously hypertensive rats (SHR)
Author(s) -
Clark Kateryna,
Kalea Anastasia Z.,
Schuschke Dale A.,
Harris Patrick D.,
KlimisZacas Dorothy J.
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.lb87-a
Subject(s) - vasodilation , vasoconstriction , phenylephrine , chemistry , nitric oxide , contraction (grammar) , endocrinology , medicine , acetylcholine , endothelium , nitric oxide synthase , pharmacology , blood pressure
We examined the effect of wild blueberries on vasodilation pathways of SHR. Weanling male SHR were fed a control (HC) or a blueberry‐enriched (HB) diet for 8wks. Aortas were excised and 3mm rings were prepared. After equilibration and preconditioning, rings were precontracted with l ‐Phenylephrine 3x10 −7 M. A concentration response curve (CRC) was produced using Acetylcholine (Ach, 10 −9 to 3x10 −6 M), to obtain endothelium‐dependent (ED‐) vasodilation. After a 30min washout period, a second Ach CRC was obtained in the presence of the inhibitors of nitric oxide (NO) synthase ( l ‐NMMA, 10 −4 M) and cyclo‐oxygenase (COX) (MFA, 10 −5 M). The percent of relaxation to the initial contraction was used to determine vessel sensitivity ( p D 2 ) to agonists. A two‐way ANOVA test showed that Ach‐induced vasodilation was significantly increased in HB rats ( p< 0.05). Inhibition of the NOS pathway significantly reduced maximum vasodilation in both diet groups (93% in HC and 83% in HB aortas). COX inhibition attenuated ED‐vasodilation in HB aortas (112%) but caused a 1.5% vasoconstriction in HC aortas, suggesting the presence of vasoconstrictor(s) in HC rats. Thus, blueberries in the SHR may operate through the COX pathway either by reducing the synthesis of vasoconstrictor and/or enhancing the synthesis of vasodilator prostanoids, with implications on NO bioavailability. This work was supported by a USDA/CSREES (WBANA) Grant.