Effect of Potassium on the Resting Length of Vascular Smooth Muscle of the Rabbit Aorta and Its Response to L-norepinephrine.

The experiments described below were designed to study the effects of changes in extracellular potassium concentration [K]o on the basal tone, the contractile response to Z-norepinephrjne and the tissue concentration of potassium [K] t of helical rabbit aorta strips. The results suggest that in this preparation when [K]o is increased, the change in resting length due to the potassium change is more important than the changes in the response to J-norepinephrine. The changes in sensitivity to Z-norepinephrine may be related to the intracellular potassium concentration.