[Sensitivity of a small artery of the muscular type to blood flow velocity: self-adjustment reaction of the artery's lumen].

The external diameter of the artery predominantly supplying the gracilis muscle was recorded by contact inductive transducer in anesthetized dogs. Blood flow from this artery was directed via an A--V shunt straight into the vein. An increase in blood flow from 4.9+/-0.7 to 45.5+/-6.6 ml/min with a latency of 11.3+/-1.3 sec evoked an increase of 12.6+/-1.3% in the diameter of this artery. Dilatation was independent of whether intravascular pressure at the recording site increased, decreased, or remained unchanged. The smooth arterial muscles seem to be able to "sense" the deformation and, as a result their arteries can automatically change their lumen in response to changes in blood flow velocity.