Sodium and potassium shifts associated with peripheral resistance changes in the dog.

Abstract

The relation of changes in peripheral vascular resistance to blood sodium and potassium activity was studied in the dog hind limb. Arterial inflow was controlled by a constant output pump in the femoral artery line. Cations were monitored with glass-to-silver cannula electrodes in the venous outflow. Vasoactive drugs were administered intra-arterially in amounts sufficient only to affect the limb vasculature. Vasoconstrietion induced by norepinephrine or epinephrine was associated with a fall in blood (Na + ) and often with a rise of (K + ). Larger doses tended to produce a biphasic response in (Na + ), a transient initial rise preceding the fall. Vasoconstrietion induced by serotonin or angio-tensin was associated with a fall in blood (Na + ) unaccompanied by any consistent change in (K + ). Vasoconstrietion induced by small amounts of pitressin (small series) produced a larger fall in (Na + ) and rise in (K + ) than with other agents producing an equal degree of vasoconstrietion. Vasodilatation induced by isoproterenol, acetylcholine, or histamine was accompanied by a rise in blood (Na + ) without any consistent change in (K + ).