Action of oxygen and potassium on vascular resistance of dog skeletal muscle

Abstract

The effects of various combina-tions of O2 and K in perfused blood on vascular resistance to blood flow through the isolated, perfused (constant flow) gracilis muscle were examined. These studies revealed that as long as the O2 delivery to the muscle was within the normal range, a reductiqn of the K concentration produced vasoconstriction, whereas substantial elevations of the concentration of this ion produced minimal to moderate, but never maximal, vasodilatation. Conversely, minimal to moderate elevations of the K concentration of O2 -deficient blood resulted in substantial reductions of vascular resistance. The higher the K concentration, the greater and the more rapid was the decrease in vascular resistance which occurred during the perfusion of O2 -deficient blood. These data indicate that the O2 and the associated K concentration of blood are importantly related to the tone maintained by the resistance vessels and that these substances interrelate and reinforce each other in determining blood flow through the resting and contracting skeletal muscle.