Mitigating the Effects of Adrenaline
Beta blockers are designed to keep norepinephrine and epinephrine, also known as adrenaline, from binding to the beta receptors. Norepinephrine and adrenaline are hormones that stimulate the "fight or flight" response, which elevates heart rate and blood pressure.
Beta receptors are molecules that receive and process signals from the nervous system. Beta 1 receptors are located in the heart, eyes and kidneys. Beta 2 receptors are located in the gastrointestinal tract, the lungs, the liver, the uterus and in skeletal muscles. Beta 3 receptors are located in the fat cells. Beta blockers block beta 1 and beta 2 receptors. When they bind to the receptor site, it is the biological equivalent to stealing the parking space of the norepinephrine and epinephrine. By preventing these hormones from binding to the beta-receptor site, they are unable to cause their usual adverse effects.
Slowing Nerve Impulses
Blocking adrenaline and norepinephrine slows the nerve impulses that travel through the heart. This eases the workload on the heart. As heart rate slows down, stress is reduced.
Dilation of Blood Vessels
Beta blockers can also dilate blood vessels, which can in turn help lower blood pressure. Constricted blood vessels impede blood flow, which causes blood pressure to rise. By dilating the blood vessels, blood flow is improved and blood pressure is lowered.
Slowing Renin Production
The beta 1 receptors in the kidneys may produce a protein called renin. The release of renin can cause the release of a blood vessel constrictor known as angiotensin II, which makes it difficult for blood to flow through the arteries. Beta blockers prevent the production of renin in the kidneys.
