Abstract
The vascular reactivities to injected angiotensin II and D, L-norepinephrine have been compared before and during the administration of spironolactone, hydrochlorothiazide and potassium chloride. The vascular reactivity was increased by spironolactone or potassium chloride, while it was decreased by chlorothiazide. The changes of vascular reactivity paralleled the concentra-tion of potassium in serum. The initial level of blood pressure did not influence the response to pressor substances.
These findings support the view that the extracellular distribution of potassium is causally involved in the maintenance of vascular tone.
