Absence of flow-mediated vasodilation in the rabbit femoral artery.
The purpose of this study was to determine if there is flow-mediated vasodilation of the femoral artery in response to progressive increases in flow within a physiological range observed in the in vivo experiments. Femoral artery blood flow was determined in conscious rabbits (n = 5) using chronically implanted flowprobes. Resting blood flow was 8.3 +/- 0.6 ml/min and increased to 39.9 +/- 5.4 ml/min during high intensity exercise. Femoral arteries (n = 12, 1705 +/- 43 microm outer diameter) harvested from a separate group of rabbits were mounted on cannulas and diameter was continuously monitored by video system. Functional integrity of the endothelium was tested with acetylcholine. The arteries were set at a transmural pressure of 100 mm Hg and preconstricted with phenylephrine to 73 +/- 3% of initial diameter. Using a roller pump with pressure held constant, the arteries were perfused intraluminally with warmed, oxygenated Krebs' solution (pH = 7.4) over a physiological range of flows up to 35 ml/min. As flow increased from 5 ml/min to 35 ml/min, diameter decreased significantly (p < 0.05) from 1285 +/- 58 microm to 1100 +/- 49 microm. Thus, in vessels with a functional endothelium, increasing intraluminal flow over a physiological range of flows produced constriction, not dilation. Based on these results, it seems unlikely that flow-mediated vasodilation in the rabbit femoral artery contributes to exercise hyperemia.
Clifford
P S
PS
Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, USA.
Madden
J A
JA
Hamann
J J
JJ
Buckwalter
J B
JB
Valic
Z
Z
D000109:Acetylcholine / Q000494:pharmacology; D000222:Adaptation, Physiological; D000818:Animals; D001783:Blood Flow Velocity; D001794:Blood Pressure; D005263:Femoral Artery / Q000187:drug effects / Q000503:physiopathology*; D006940:Hyperemia / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000098:blood supply*; D005082:Physical Exertion; D011817:Rabbits; D012039:Regional Blood Flow; D014661:Vasoconstriction; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
D014665:Vasodilator Agents; D000109:Acetylcholine