Blood Pressure and Vascular Design in Renal Hypertension in Rats after Prolonged Propranolol Treatment

To study the effect of β‐adrenergic blockade on the development of renal hypertension, propranolol was given by administration in the drinking water to 4 week old normotensive male Wistar rats. After 3 weeks of treatment the left renal artery was constricted by a silver clip in order to induce renal hypertension, the same procedure being performed in a group of matched untreated controls. ‐ The incidence and degree of hypertension 4 weeks after renal artery constriction was about the same in both groups, but heart rate was considerably‐lower in the propranolol‐treated animals, and heart rate responses to isoprenaline were diminished. Treatment was continued until 4 weeks after constriction, when quantitative hemodynamic analysis of the hindquarter vascular beds revealed the same degree of structural vascular changes in both treated and untreated renal hypertensive rats. ‐ Another group of rats, in which renal hypertension and hypertensive cardiovascular changes were already established, was treated with propranolol for 3 months. No effect on arterial pressure was noticed, but heart rate was considerably reduced. Thus, renal hypertension appears to be unaffected by adrenergic β‐receptor blockade, in contrast to the situation in early phases of hypertension in spontaneously hypertensive rats (Folkow, Lundgren and Weiss 1972).