M. Cabel et al., ATTENUATION OF BLOOD FLOW-INDUCED DILATION IN ARTERIOLES AFTER MUSCLE-CONTRACTION, The American journal of physiology, 266(5), 1994, pp. 80002114-80002121
The response of third-order arterioles (n = 15) in rat-cremaster muscl
e to increased luminal flow was studied after brief (20-30 s) occlusio
n of a neighboring arteriole in pentobarbital-anesthetized rats. Red c
ell velocity increased almost fivefold (485 +/- 54% of control) during
occlusion, and vessel diameter increased 63 +/- 11%. Initially, the c
alculated wall shear rate increased to 430 +/- 40% of control during o
cclusion but then decreased to 308 +/- 35% of control as a consequence
of arteriolar dilation. The muscle was subsequently stimulated to con
tract for 1 min, and the occlusion procedure was repeated after arteri
olar diameter and red cell velocity had returned to control levels. In
this instance the vessel dilation was 34 +/- 10% or about one-half of
that seen during the previous occlusion, although velocity and shear
rate rose to a similar degree (474 +/- 54 and 397 +/- 35%, respectivel
y). Dilation during a third occlusion 2-7 min after the vessel recover
ed from the second occlusion was as great as during the first occlusio
n (77 +/- 20%). The results indicate that flow-induced dilation in art
erioles of rat cremaster muscle is transiently attenuated after muscle
contraction.