Salt-induced hypertension in the dog

Abstract

Arterial hypertension was successfully induced in two groups of dogs by increasing the dietary intake of NaCl to 2 g/kg body wt/day and providing 0.9% saline instead of tap water to drink. In the first group the arterial pressure increased approximately 55% over a period of 26 days. Restriction of dietary K intake had no effect on this response. In the second group, catheters were chronically implanted in the right atrium and aorta, prior to salt feeding. Control animals were similarly catheterized. In these conscious, unrestrained animals, salt hypertension was found to be associated with a marked increase in blood volume and cardiac output. The latter was attributable to an increase in stroke volume rather than heart rate. Calculated peripheral resistance was not altered by salt feeding nor was the concentration of plasma Na. Total exchangeable Na, however, was approximately doubled.