Blood-borne vasodilating agent from ischemic tissues

Abstract

Plethysmographic measurements of forearm blood flow show a drop to minimal values immediately after release of arterial occlusion of a leg; this is soon followed by a somewhat greater and more sustained increase to values above the control. Prepacking the leg with blood before arterial occlusion, or exercise before occlusion, or a combination of these procedures does not significantly alter the response. Calculated peripheral resistance in the forearm follows the pattern implied by the blood flow changes. It is suggested that the initial vasoconstriction is a reflex whereas the later vasodilatation is due to a stable, circulating agent from the previously ischemic leg. Submitted on April 29, 1960