What are the functions of salbutamol?

Salbutamol is a beta 2 adrenoceptor agonist. It binds therefore to Beta 2 receptors found particularly in the bronchioles of the respiratory system. In binding to these receptors it activates the Gs protein that the receptor is associated with and GDP is exchanged for GTP. This then activates the enzyme adenylate cyclase that coverts ATP into cAMP (a secondary messenger). Increased intracellular cyclic AMP (cAMP) increases the activity of cAMP dependent protein kinase A, which alters the phosphorylation of myosin and lowers intracellular calcium levels within the muscle. Lower levels of calcium cause relaxation of the smooth muscle and therefore bronchodilatation.

Bingo! The airways dilate and everyones happy!