The change of vascular reactivity to angiotensin II and norepinephrine in the two-kidney, one-clip renovascular hypertensive rabbit.

The change of the response to angiotensin II (AII) and norepinephrine (NE) was evaluated in vivo and vitro in the chronic phase of two-kidney, one-clip renovascular hypertensive rabbits. In the constricted group, systemic blood pressure (BP) was significantly higher and plasma renin activity (PRA) was significantly lower than in the control group. Subpressor doses of AII and NE injections in the constricted group produced significant elevations of BP. In the aortic, renal and iliac arterial strips, the reactivity to AII (10(-10) to 10(-8) M) and NE (10(-10) to 10(-7) M) was significantly increased in the constricted group as compared to the control group. In the constricted group, sodium loading produced BP elevation with decreased PRA and shifted the dose-response curves by AII and NE to the left, whereas sodium restriction decreased BP and shifted the curves to the right. In the control group, altered sodium intake did not affect BP but affected only the dose-response curves by AII. These results suggested that in the chronic phase of renovascular hypertensive rabbits, the increased reactivity to AII and NE may contribute to the maintenance of hypertension.