Angiotensin II causes muscles in most arteries, including the arteries of the heart, to contract, thereby narrowing the arteries and elevating
blood pressure. ACE inhibitors such as
ramipril lower
blood pressure by reducing the production of angiotensin II, thereby relaxing arterial muscle and enlarging arteries.
In the kidneys, the narrowing of the arteries by angiotensin II decreases blood flow. ACE inhibitors enlarge and reduce the blood pressure in the arteries going to the kidney.