Attenuation of endothelium-dependent hyperpolarizing factor by bacterial lipopolysaccharides.
Endothelium-dependent hyperpolarizing factor (EDHF) is an important contributor to agonist-induced vascular dilation. Recent studies suggest that bacterial lipopolysaccharides attenuate endothelium-dependent dilation. Whether or not this effect is mediated through inhibition of EDHF is not known. We studied the in vitro influence of Escherichia coli lipopolysaccharides on endothelium-dependent smooth muscle dilation and hyperpolarization in porcine coronary arteries. Endothelium-intact porcine coronary arterial rings were examined after 20 h of incubation with either saline or E. coli lipopolysaccharides (100 microg/ml). Endothelium-dependent dilation elicited by increasing concentrations of bradykinin was significantly attenuated by lipopolysaccharides. Baseline values of smooth muscle membrane potential were not influenced by lipopolysaccharides. However, lipopolysaccharides significantly attenuated bradykinin-induced smooth muscle membrane hyperpolarization. Our results suggest that attenuation of EDHF is an important mechanism through which lipopolysaccharides influence vascular dilation in severe sepsis.
Kristof
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AS
Critical Care and Respiratory Division, Royal Victoria Hospital, McGill University, Montreal, Québec, Canada.
Noorhosseini
H
H
Hussain
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SN
D000704:Analysis of Variance; D000818:Animals; D001685:Biological Factors / Q000378:metabolism*; D001920:Bradykinin / Q000494:pharmacology*; D003331:Coronary Vessels / Q000187:drug effects / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D066298:In Vitro Techniques; D008070:Lipopolysaccharides / Q000633:toxicity*; D008564:Membrane Potentials / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009569:Nitric Oxide / Q000378:metabolism; D013552:Swine; D014664:Vasodilation / Q000187:drug effects*
D001685:Biological Factors; D008070:Lipopolysaccharides; C067410:endothelium-dependent hyperpolarization factor; D009569:Nitric Oxide; D001920:Bradykinin