THE DIFFUSION OF POTASSIUM FROM RESTING SKELETAL MUSCLES FOLLOWING A REDUCTION IN THE BLOOD SUPPLY

Abstract

When the blood supply through the resting hind leg of a cat was reduced by hemorrhage, vasoconstriction, or temporary blocking of the arterial supply, the K content of the femoral venous blood plasma remained fairly constant until the rate of flow in the femoral vein was below 80% of its normal value. Further reduction beyond this critical point led to a rapid and marked increase in K, due to a diffusion of K from the muscles. There was, however, no marked decrease in the irritability of the resting muscle as measured by the height of occasional isotonic contractions. The reduction in blood flow led to a dilution of the blood with tissue fluid but the increase in K did not show any clear relation to the extent of dilution, and allowance for the dilution did not affect the results. Stimulation of the lower abdominal sympathetic chain caused an increase in the K, but this was no greater than could be accounted for by the reduction in blood flow due to the accompanying vasoconstriction.