[Hemodynamic changes in the acute phase of experimental hypertension]

The arterial pressure, heart rate, cardiac output, stroke volume, total peripheral resistance and plasma angiotensin II were measured in Wistar rats and 24 hours after arterial renal constriction by a clip (0.20 mm d.i.). The results were compared with those obtained in a sham operated group. The experimental group showed an increase in arterial pressure and total peripheral resistance without changes in heart rate, cardiac output and stroke volume. In hypertensive animals there was a greater level of plasma angiotensin II than in control group. These studies have demonstrated that 24 hours after renal arterial stenosis the increase in arterial pressure can be mediated by an increased activity of the renin-angiotensin system.