Shear-dependent release of venular nitric oxide: effect on
arteriolar tone in rat striated muscle .
Boegehold, Matthew A.
Department of Physiology, West Virginia University School of
Medicine, Morgantown, West Virginia 26506-9229
APStracts 2:0570H, 1995.
This study was designed to determine if shear-dependent changes in
venular NO production can influence nearby arteriolar tone, and if
this mechanism contributes to functional arteriolar dilation in
contracting muscle. In resting spinotrapezius muscle of anesthetized
rats, occluding one branch of an arcade venule bifurcation with
divergent flow caused flow and wall shear rate in the parallel branch
to increase by an average of 99% and 72%, respectively. After 10-30
s, the paired arcade arteriole dilated by an average of 30%, with a
correlation between the increase in venule shear rate and the
magnitude of arteriolar dilation. During muscle contraction, arcade
arterioles dilated by 73-97% and arcade venule shear rate increased
by 48-83%. The NO synthase inhibitor NG-monomethyl L-arginine greatly
attenuated arteriolar dilation to increased venule shear rate in
resting muscle but did not affect arteriolar dilation in contracting
muscle. These findings suggest that a shear-dependent increase in
venular NO release can dilate nearby arterioles, but this mechanism
is not important for the sustained dilation of these arterioles
during functional hyperemia.
Received 20 September 1995; accepted in final form 11 December
1995.
APS Manuscript Number H889-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 December 95