Maximum effect of bronchodilatation in asthma is caused by -

Ans. is 'd' i.e., b2-Agonist b-agonists in Asthmao Bronchi have b2-adrenergic receptors which cause bronchodilatation - So, the adrenergic drugs used in asthma are selective b2 agonists.o b2-agonists are the most effective bronchodilatorso b2-agonists have some other effects also on airways (other than bonrchodilatation), that are responsible for beneficial effects in asthma:Inhibition of release of mast cells mediators -mast cells stabilizing action.Inhibition of exudation and airway edema.Increased mucociliary clearanceDecreased cougho b2-agonists have no effect on inflammation - no antiinflammatory action.