Abstract
The role of wild blueberries (WB) on key signaling steps of nitric oxide (NO) and cyclooxygenase (COX) pathways was examined in spontaneously hypertensive rats (SHRs) after eight weeks on a control (C) or an 8% w/w WB diet. Aortic rings from SHRs were stimulated with phenylephrine (Phe) in the absence or presence of inhibitors of: soluble guanylyl cyclase (sGC), phosphodiesterase-5 (PDE(5)), prostaglandin I(2) (PGI(2)) synthase and thromboxane A(2) (TXA(2)) synthase. Additionally, enzymatic activities in these pathways were determined by the concentration of NO, cyclic guanosine monophosphate (cGMP), PGI(2) and TXA(2). In the WB-fed SHR, attenuation of Phe-induced vasoconstriction was mediated by an increased synthesis or preservation of cGMP. Despite an increased release of PGI(2) in the WB group, neither inhibition of PGI(2) or TXA(2) synthase resulted in a different response to Phe between the control and the WB rings. Hence, in the SHR, WB decrease Phe-mediated vasoconstriction under basal conditions by enhancing NO-cGMP signaling without a significant involvement of the COX pathway.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adrenergic alpha-1 Receptor Agonists / pharmacology
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Animals
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Aorta / drug effects
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Blueberry Plants*
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Cyclic GMP / metabolism*
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Cytochrome P-450 Enzyme Inhibitors
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Cytochrome P-450 Enzyme System / metabolism
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Diet*
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Enzyme Inhibitors / pharmacology
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Epoprostenol / metabolism
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Fruit*
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Hypertension / diet therapy*
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Hypertension / metabolism
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Intramolecular Oxidoreductases / antagonists & inhibitors
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Intramolecular Oxidoreductases / metabolism
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Male
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Nitric Oxide / metabolism*
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Nitric Oxide Synthase / metabolism
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Phenylephrine / pharmacology
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Plant Preparations / pharmacology
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Plant Preparations / therapeutic use
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Prostaglandin-Endoperoxide Synthases / metabolism
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Rats
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Rats, Inbred SHR
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Signal Transduction
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Thromboxane A2 / metabolism
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Thromboxane-A Synthase / antagonists & inhibitors
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Thromboxane-A Synthase / metabolism
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Vasoconstriction / drug effects*
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Vasodilator Agents / pharmacology
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Vasodilator Agents / therapeutic use
Substances
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Adrenergic alpha-1 Receptor Agonists
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Cytochrome P-450 Enzyme Inhibitors
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Enzyme Inhibitors
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Plant Preparations
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Vasodilator Agents
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Phenylephrine
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Nitric Oxide
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Thromboxane A2
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Cytochrome P-450 Enzyme System
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Epoprostenol
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Nitric Oxide Synthase
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Prostaglandin-Endoperoxide Synthases
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Intramolecular Oxidoreductases
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prostacyclin synthetase
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Thromboxane-A Synthase
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Cyclic GMP