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Arteriolar Dilation Produced by Venule Endothelium‐Derived Nitric Oxide
Author(s) -
Falcone Jeff C.,
Meininger Gerald A.
Publication year - 1997
Publication title -
microcirculation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.793
H-Index - 83
eISSN - 1549-8719
pISSN - 1073-9688
DOI - 10.3109/10739689709146793
Subject(s) - venule , arteriole , bradykinin , vasodilation , microcirculation , chemistry , nitric oxide , acetylcholine , endothelium , anatomy , perfusion , medicine , endocrinology , biochemistry , receptor
Objective: We conducted bioassay experiments to determine whether nitric oxide produced by endothelial cells (endothelial‐derived nitric oxide, or EDNO) within large venules could act to dilate arterioles. Methods: In these experiments, parallel segments of first‐order arterioles and venules were isolated from skeletal muscle and were cannulated in series with a glass connecting tube (length: 300–500 μm). Arterioles were mechanically denuded of endothelium by a delicate yet abrasive rubbing technique. Venular endothelium remained intact. Endothelial denudation of arterioles was confirmed by the absence of dilation during exposure to acetylcholine (10 −6 mol/L). The cannulated vessels were pressurized to 30 cm H 2 O and the arterioles preconstricted by approximately 50% with norepinephrine (10 −10 mol/L). Results: Topical applications of acetylcholine (10 −6 mol/L) or bradykinin (10 −9 mol/L) during luminal perfusion from venule to arteriole produced significant arteriolar dilation. In contrast, a slight arteriolar constriction was observed when the direction of flow was reversed (i.e., arteriole to venule) in the presence of either acetylcholine (10 −6 mol/L) or bradykinin (10 −9 mol/L). Inhibition of venular EDNO with; N C ‐monomethyl‐L‐arginine (L‐NMMA; 10 −5 mol/L; 1 hour) completely abolished the arteriolar dilation observed in response to acetylcholine or bradykinin during venule to arteriole perfusion. Conclusions: These results demonstrate that venular‐derived EDNO can relax arteriolar vascular smooth muscle.