Hypertension caused by salt loading. II: Fluid volume and tissue pressure changes

Abstract

Experimental hypertension was produced in dogs by increasing their dietary intake of sodium chloride after removing approximately 70% of their renal tissue. The changes in mean arterial pressure, interstitial fluid pressure, blood volume, and sodium space were observed during the development and maintenance of the hypertension. During the periods of increased salt intake, the arterial pressure increased from a mean of 114.6 mm Hg to a mean of 150.6 mm Hg, and there were concomitant increases of 19.8% in blood volume, 16% in sodium space, and 4 cm H2O in interstitial fluid pressure. However, the increases in all the paramteers studied except arterial pressure were transient. The blood volume remained elevated above control values for a longer period of time than the sodium space and interstitial fluid pressure, but it reapproached normal after approximately 16–20 days.