What is the mechanism of action of ACE inhibitors?

ACE inhibitors work by inhibiting the angiotensin-converting enzyme, which plays a crucial role in the renin-angiotensin-aldosterone system (RAAS). This action prevents the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor. As a result, the vasodilation that follows leads to a decrease in blood pressure and reduced workload on the heart.

Additionally, by decreasing angiotensin II levels, ACE inhibitors reduce the secretion of aldosterone, leading to decreased sodium and water retention, further contributing to lower blood pressure. This mechanism makes ACE inhibitors effective for treating conditions such as hypertension, heart failure, and certain kidney disorders.

The other mechanisms of drug action listed in the options don't apply to ACE inhibitors. Blockade of beta-adrenergic receptors pertains to a different class of medications, and increasing insulin sensitivity or stimulating the release of norepinephrine relates to entirely separate pathways and therapeutic uses.