Abstract
Muscle blood flow at rest and after exercise was measured by the clearance of injected 133Xe. When noradrenaline was mixed with the 133Xe solution, local vasoconstriction was produced at rest, during, and after exercise. The vasoconstriction was dose dependent in the range 1-100 μg noradrenaline base/ml. We conclude that in human muscle local noradrenaline effectively both reduces resting blood flow and antagonizes work-induced hyperemia.