Water and Electrolyte Content of Normal and Hypertensive Arteries in Dogs

This study was designed to establish values for the water and electrolyte content along the arterial tree in the dog under normal conditions and to determine how the normal electrolyte pattern was altered in renal hypertension. Determinations of vessel wall water, potassium, sodium, and chloride contents have shown that the water and electrolyte contents from the various sites along the arterial tree differ significantly from each other. Total water and potassium contents decrease progressively from the ascending aorta to the femoral and carotid sites, while the sodium and chloride contents showed the opposite trend. These differences were significant statistically. These trends may not persist along the entire vascular tree to very small arteries, as indicated by analysis of mesenteric arterial samples. Studies of vessel wall inulin space supported the view that these differences result from the relative distribution of cellular and noncellular material; thus the proximal aorta contains a relatively greater proportion of cellular (smooth muscle) material than more distal sites such as the femoral and carotid arteries. A review of the literature further supports these findings. In experimentally induced renal hypertension the same trends persist along the aorta, but the total water and sodium contents are significantly elevated at all sites.