What are the functions of salbutamol?

Answer 1

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!

Answer 2

salbutamol is specifically indicated in the following conditions: * acute Asthma * symptom relief during maintenance therapy of asthma and other conditions with reversible airways obstruction (including COPD) * protection against exercise-induced asthma * hyperkalaemia, especially in patients with renal failure * can be aerosolized with a nebulizer for patients with cystic fibrosis, along with ipratropium bromide and pulmozyme. As a β2-agonist, salbutamol also finds use in obstetrics. Intravenous salbutamol can be used as a tocolytic to relax the uterine smooth muscle to delay premature labour. Whilst preferred over agents such as atosiban and ritodrine, its role has largely been replaced by the calcium-channel blocker nifedipine which is more effective, better tolerated and orally administered.[1] Salbutamol is taken by some as an alternative to Clenbuterol for purposes of fat burning As with other β2-adrenergic receptor agonists, salbutamol binds to β2-adrenergic receptors with a higher affinity than β1-receptors. In the airway, activation of β2-receptors results in relaxation of bronchial smooth muscle resulting in a widening of the airway (bronchodilation). Inhaled salbutamol sulfate has a rapid onset of action, providing relief within five to fifteen minutes of administration.

In tocolysis, the activation of β2-receptors results in relaxation of uterine smooth muscle, thus delaying labour.