β2-Adrenoceptors are mainly postsynaptic receptors. They are expressed on a number of tissues including blood vessels, bronchi, gastrointestinal tract (GIT), skeletal muscle, liver and mast cell.Functional β2-Adrenoceptors were also found on lymphocytes, macrophages and neutrophils.They are also the only β-Adrenoceptor subtype expressed in keratinocytes, fibroblasts and melanocytes. Activation of β2-Adrenoceptors results in vasodilation, relaxation of the GIT, inhibition of histamine release from mast cells and bronchodilation. Selective agonists of β2-Adrenoceptors are used to treat asthma and other related bronchospastic conditions such as Chronic obstructive pulmonary disease (COPD).