title: Effects of ischemia and hemoglobin on vascular function in isolated rabbit aortas.
abstract: The vascular endothelium is important in the modulation of vascular tone via production of endothelium-derived relaxing and contracting factors. The abdominal aortas of five groups of rabbits were subjected to varying lengths of ischemia (0, 1, 2, 3, or 4 hours), removed, sectioned into transverse rings, and placed in tissue baths containing Krebs' buffer at 37 degrees C and aerated with 95% O2/5% CO2. After equilibration the rings were tested for endothelium-dependent vasodilation with methacholine and nonendothelium-dependent vasodilation with nitroprusside. Endothelium-dependent relaxation as elicited by methacholine was impaired at 3 and 4 hours of ischemia but was not significantly different at 1 and 2 hours as compared to control, whereas endothelium-independent vasodilation remained normal throughout the different periods of ischemia. The addition of 1 x 10(-6) mol/L rabbit hemoglobin reduced the time needed to demonstrate significant impairment of endothelial function to 2 hours. Endothelium-independent vasodilation was not affected by hemoglobin. We conclude that hemoglobin exacerbates ischemia vascular dysfunction in the rabbit aorta.
authors.affiliation: Department of Surgery, University of Virginia Health Sciences Center, Charlottesville 22908.
authors.forename: A J
authors.initials: AJ
authors.lastname: Ruiz
authors.forename: B B
authors.initials: BB
authors.lastname: Chan
authors.forename: T A
authors.initials: TA
authors.lastname: Meyerhoefer
authors.forename: D R
authors.initials: DR
authors.lastname: Buck
authors.forename: P C
authors.initials: PC
authors.lastname: Farley
authors.forename: T L
authors.initials: TL
authors.lastname: Flanagan
authors.forename: I L
authors.initials: IL
authors.lastname: Kron
mesh_terms: D000818:Animals; D001012:Aorta, Abdominal / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology*; D006454:Hemoglobins / Q000008:administration & dosage / Q000494:pharmacology*; D007511:Ischemia / Q000473:pathology / Q000503:physiopathology*; D016210:Methacholine Chloride / Q000008:administration & dosage / Q000494:pharmacology; D009569:Nitric Oxide / Q000037:antagonists & inhibitors*; D009599:Nitroprusside / Q000008:administration & dosage / Q000494:pharmacology; D011817:Rabbits; D013997:Time Factors; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*
chemical_list: D006454:Hemoglobins; D016210:Methacholine Chloride; D009599:Nitroprusside; D009569:Nitric Oxide