Wild blueberry‐enriched diet affects α1‐adrenergic induced vasoconstrictor response in the aorta of obese Zucker rats

Abstract

This study investigates the effects of wild blueberry (WB, Vaccinium angustifolium) on arterial contractile response to the α1‐adrenergic agonist phenylephrine (Phe) in 8 week old obese Zucker rats (OZR). Twenty OZR were randomly assigned to a control (C) or an 8% WB diet for 8 weeks. Vascular studies were conducted in isolated aortic ring preparations to measure vasoconstriction induced by Phe, 10–8 to 3×10–6M. Plasma nitric oxide (NO) and aortic concentration of prostacyclin (PGI2) and thromboxane A2 (TXA2) in the effluent was determined.Obese Zucker rats exhibited a reduced response to Phe‐induced vasoconstriction, possibly due to a compensatory overproduction of NO under inflammatory conditions. The WB diet partially restored Phe‐induced constrictor responses, compared to their lean littermates, by increasing the maximal force developed (0.55±0.02 g WB vs 0.43±0.02 g C, p≤0.05)Plasma NO was significantly attenuated (22.1±1.1 μmol/L, WB vs 25.6±1.4 μmol/L, C, p≤0.05) with the WB diet. Aortic effluent TXA2 levels were not significantly altered, while PGI2 concentration significantly increased (766.5±92.2 pg/mg WB vs 571.7±37.8 pg/g C aorta, p≤0.05).In conclusion, WB consumption significantly altered vasomotor tone in response to an α1‐adrenergic agonist in the OZR aorta and modulated plasma NO and aortic effluent PGI2.Grant Funding Source: Wild Blueberry Association of North America