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Adenosine is known to play an important role in the regulation of coronary blood flow during metabolic stress. However, there is sparse information on the mechanism of adenosine-induced dilation at the microcirculatory levels. In the present study, we examined the role of endothelial nitric oxide (NO), G proteins, cyclic nucleotides, and potassium channels(More)
Adenosine is a potent vasodilator of the coronary microvessels and is implicated in the regulation of coronary blood flow during metabolic stress. However, the receptor subtypes and the vasodilatory mechanism responsible for the dilation of coronary microvessels to adenosine remain unclear. In the present study, using an isolated-vessel preparation we(More)
Angiotensin II (Ang II) is a potent vasoconstrictor in the peripheral circulation and has been implicated in many cardiovascular diseases associated with elevated oxidative stress. However, its direct vasomotor action and its linkage to oxidative stress-induced vascular dysfunction in the coronary microcirculation remain elusive. In this study, we directly(More)
Our previous studies implicated that oxidized low-density lipoprotein (oxLDL), a putative atherogenic agent, impairs endothelium-dependent, nitric oxide (NO)-mediated dilation of isolated coronary arterioles to pharmacological agonists. However, it is not known whether oxLDL specifically affects NO-mediated dilation or generally impairs(More)
Adenosine is a potent vasodilator that plays an important role in the regulation of coronary microvascular diameter. Although multiple adenosine receptor subtypes have been recently cloned, the specific adenosine receptor subtypes and the underlying mechanisms responsible for the vasodilation to adenosine in the coronary microcirculation remain unknown.(More)
PURPOSE Resveratrol, a polyphenolic phytoalexin found in grapes and red wine, has been shown to exert cardiovascular benefits, but its action in the retinal microcirculation remains unknown. In this study, the direct effect and the underlying mechanism of the vasomotor action of resveratrol were examined in retinal arterioles. METHODS Porcine retinal(More)
Integrin binding by Arg-Gly-Asp (RGD)-containing peptides has been shown to alter vascular tone in a variety of blood vessels and has been implicated as a mechanism of vasoregulation during tissue injury. However, the effect of these peptides in the coronary circulation has not been examined. Thus the purpose of our study was to test the hypothesis that(More)
Nitric oxide (NO) produced by the endothelium diffuses both into the lumen and to the smooth muscle cells according to the concentration gradient in each direction. The extremely high reaction rate between NO and hemoglobin (Hb), k(Hb)= 3-5 x 10(7) M(-1).s(-1), suggests that most of the NO produced would be consumed by Hb in the red blood cells (RBCs),(More)
OBJECTIVE Elevated levels of C-reactive protein (CRP), a proinflammatory marker, are associated with reduced systemic endothelium-dependent NO-mediated dilation in patients with coronary artery disease; however, the direct effect of CRP on coronary microvascular reactivity remains unknown. Herein, we examined whether CRP can modulate endothelium-dependent(More)
BACKGROUND AND OBJECTIVE Elevated C-reactive protein (CRP) levels are associated with increased cardiovascular events and endothelial dysfunction. We have previously shown that CRP decreases endothelial nitric oxide synthase (eNOS) activity in endothelial cells and inhibits endothelium-dependent nitric oxide (NO)-mediated vasodilation in vitro. Herein, we(More)