The beta-2 adrenergic receptor (ADRB2) is an important target for epinephrine, a neurotransmitter in pain signalling. ADRB2 haplotypes affect receptor expression and ligand response, and have been linked to painful non-GI disorders. The beta-2 adrenergic receptor (ADRB2) Arg16Gly polymorphism may alter the bronchodilation response to long-acting beta2-agonists, thereby influencing the clinical effectiveness of LABAs plus corticosteroids (ICS) treatment. The beta-2-adrenergic receptor (ADRB2) gene has an important impact on smooth muscle relaxation, including the smooth muscles of the uterus. In hypercholesterolemic hearts, the expression of Adrb2 mRNA was significantly decreased. The beta2-adrenergic receptor (ADRB2) is an important regulator of airway smooth muscle tone in chronic obstructive pulmonary disease (COPD). Variants that impair ADRB2 function could increase disease risk or reduce the response to endogenous and inhaled adrenergic agonists in COPD. Beta-2 adrenergic receptor (ADRB2) is the primary target of both short- and long-acting beta-agonist asthma medications. But (ADRB2) polymorphism on therapeutic responses to long-acting beta(2)-adrenergic agonists have not been evaluated in long-term COPD trials.