beta2receptorn

The beta-2 adrenergic receptor, also known as ADRB2, is a protein that in humans is encoded by the ADRB2 gene. This gene is part of the adrenergic receptor gene family, which are G protein-coupled receptors that bind to catecholamines like epinephrine and norepinephrine. The beta-2 adrenergic receptor is primarily activated by epinephrine, and to a lesser extent by norepinephrine.

This receptor plays a crucial role in the sympathetic nervous system's "fight or flight" response. Upon activation, it triggers a cascade of intracellular events, leading to various physiological effects. These include relaxation of smooth muscle in the airways (bronchodilation), which is why beta-2 agonists are commonly used to treat asthma and other respiratory conditions. It also contributes to glycogenolysis in the liver, increasing blood glucose levels, and can affect heart rate and contractility, though its effects on the heart are less pronounced than beta-1 receptors.

The beta-2 adrenergic receptor is widely distributed throughout the body, found in significant amounts in the lungs, smooth muscle, liver, and heart. Genetic variations in the ADRB2 gene can influence an individual's response to certain medications, particularly beta-2 agonists, and may also be associated with differences in metabolic regulation and athletic performance.