Osmosis video - Adrenergic antagonists: Alpha blockers

Adrenergic antagonists are a type of drug that blocks the action of adrenaline in the body. Adrenaline is a hormone that is released in response to stress or excitement, and it causes the heart rate to speed up and the blood vessels to narrow.

Alpha-blockers are a type of adrenergic antagonist that blocks the action of adrenaline on the alpha receptors. The alpha receptors are found in the muscles around the blood vessels, and when they are activated, they cause the blood vessels to narrow. Alpha-blockers, therefore, cause the blood vessels to widen, which lowers blood pressure and improves symptoms of congestive heart failure.