Effects of obesity on endothelium-dependent reactivity during acute nitric oxide synthase inhibition: modulatory role of endothelin.
This study investigated vascular reactivity in response to acetylcholine, in the presence of acute inhibition of nitric oxide synthase, in the carotid artery and aorta of obese C57Bl6/J mice fed on a high-fat diet for 30 weeks, and of control mice. A subgroup of obese animals was also treated with the ET(A) receptor antagonist darusentan (50 mg x kg(-1) x day(-1)). In vascular rings from control animals, acetylcholine caused endothelium-dependent contractions in the carotid artery, but not in the aorta. In vascular rings from obese mice, contractility to acetylcholine was also evident in the aorta, and that in the carotid artery was increased compared with control mice. ET(A) receptor blockade by darusentan treatment of the obese mice prevented enhanced vasoconstriction to acetylcholine, resulting in mild vasodilatation. Thus obesity increases endothelium-dependent vasoconstriction in the absence of endothelial nitric oxide. This effect can be completely prevented by chronic ET(A) receptor blockade, suggesting that endothelin modulates increased endothelium-dependent vasoconstriction in obesity.
Traupe
Tobias
T
Department of Internal Medicine and Medical Policlinic, University Hospital Zürich, CH-8091 Zürich, Switzerland.
D'Uscio
Livius V
LV
Muenter
Klaus
K
Morawietz
Henning
H
Vetter
Wilhelm
W
Barton
Matthias
M
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001011:Aorta; D002339:Carotid Arteries; D065128:Endothelin Receptor Antagonists; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D009765:Obesity / Q000378:metabolism*; D010666:Phenylpropionates / Q000494:pharmacology*; D011743:Pyrimidines / Q000494:pharmacology*; D044022:Receptor, Endothelin A; D014665:Vasodilator Agents / Q000494:pharmacology
D065128:Endothelin Receptor Antagonists; D010666:Phenylpropionates; D011743:Pyrimidines; D044022:Receptor, Endothelin A; D014665:Vasodilator Agents; C107831:darusentan; D019001:Nitric Oxide Synthase; D000109:Acetylcholine; D019331:NG-Nitroarginine Methyl Ester