What is the therapeutic effect of angiotensin converting enzyme (ACE) inhibitors?

Angiotensin converting enzyme (ACE) inhibitors primarily work by reducing the constriction of blood vessels. They achieve this by inhibiting the enzyme that converts angiotensin I to angiotensin II, a potent vasoconstrictor. By decreasing the levels of angiotensin II, blood vessels relax and widen, leading to a reduction in blood pressure. This therapeutic effect is especially beneficial in treating conditions such as hypertension and heart failure.

The other choices do not accurately reflect the primary therapeutic effects of ACE inhibitors. For example, increasing heart rate or blood volume would not be desirable effects of a medication meant to lower blood pressure, nor does it relate to the mechanism of ACE inhibitors. Additionally, bronchial dilation is more commonly associated with medications such as bronchodilators rather than ACE inhibitors, which do not have a direct impact on airway smooth muscle.