Beta blockers are a category of drugs used to treat various heart disorders. They work by reducing stress on the heart, regulating heart rate and lowering blood pressure. Their mechanism of action is the targeting and antagonizing the signaling of beta receptors primarily in the heart and blood vessels. Examples of beta blockers are propranolol, metoprolol, acebutolol, bisoprolol and esmolol.
Beta Receptors
Beta receptors are protein molecules, found at high levels in the heart and blood vessels, which send signals to the body through the central nervous system and hormones. When stimulated, this signaling can cause an increase in blood pressure and heart rate. The three types of beta receptors are beta 1, beta 2, and beta 3. Beta 1 receptors are located in the heart and kidneys. When stimulated, beta 1 can promote an increase in heart rate and release of renin from the kidneys. Beta 2 receptors are found in the smooth and skeletal muscles, uterus, GI tract, liver and lungs. When stimulated, beta 2 can induce relaxation of smooth muscles, tremors in skeletal muscles and break down glycogen in the liver and skeletal muscle. Beta 3 receptors are found in the fat cells and can induce lipolysis when stimulated. Beta blockers work to inhibit and control the body's response to beta receptors.
Treatment of High Blood Pressure
The four types of beta blockers are nonselective, beta 1 selective, beta 2 selective and mixed alpha/beta adrenergic antagonist. Beta blockers used to lower blood pressure are usually beta 1, beta 2 or nonselective. In the event of high blood pressure, beta blockers reduce or block the binding of norepinephrine and epinephrine (adrenaline) to beta 1 and beta 2 receptors. This blocking inhibits the body's heightened response to the receptor signals which will reduce and control heart rate and blood pressure.
Tags: heart rate, Beta receptors, beta beta, beta beta, Beta blockers, beta blockers, beta receptors