A canine hind-limb exercise model is described that permits study of pressure and flow changes through an area of arterial stenosis before, during, and after exercise.
Following creation of a critical stenosis in the external iliac artery (50% reduction in flow), exercise alone resulted in an increase in flow over the stenosis related to the degree of exercise produced, accompanied by a widening of the arteriovenous oxygen difference and an increase in oxygen consumption.
Infusion of an intra-arterial vasodilator (tolazoline hydrochloride) during the exercise period resulted in only a negligible change in flow over the stenosis, but a marked narrowing of the arteriovenous difference (30%) with a resulting reduction in limb oxygen consumption.
These findings suggest that this intraarterial vasodilator opens arteriovenous shunts, apparently bypassing the capillary bed.