Abnormal ion and water composition of veins and normotensive arteries in coarctation hypertension in rats.

Abstract

The water, Na and K composition of the thoracic aorta, abdominal aorta (plus iliac arteries) and veins (vena cava and portal vein) from rats with aortic coarctation were examined. The aortas of 10 rats (group A) were coarcted above the renal arteries to produce hypertension. Control groups consisted of 10 rats sham-coarcted above and 10 rats coarcted below the renal arteries. In group A rats, heart weights and carotid artery pressures were elevated over controls (P < 0.01), whereas there were no significant differences in femoral arterial pressures. In group A rats, both the hypertensive thoracic aorta and the normotensive abdominal aorta contained about 20% more water per unit of wet weight, and about 35% and 60% more Na and K, respectively, per unit of dry weight than did the corresponding portions of aorta from control rats (P < 0.01). In group A rats, water (P < 0.01), Na (P < 0.02) and K (P < 0.05) contents of veins also were increased. There were no significant correlations between level of carotid arterial pressure and magnitude of changes in arterial and venous composition, nor were there significant differences between the magnitude of changes in the normotensive and hypertensive portions of the aorta. In rats abnormalities in vascular wall salt and water content are not necessarily a direct effect of the elevated pressure in hypertension.