17.01.4 Drugs to Treat

The drugs used to treat asthma or COPD are bronchodilators. On bronchial smooth muscle, adrenaline acts at β₂-adrenoceptors to cause bronchodilation, and this effect can mimiced by the β₂-adrenoceptor agonist, salbutamol (Figure 17.2).

Bronchial smooth muscle is contracted by acetylcholine acting at muscarinic M₂-receptors, and by leukotrienes acting at leukotriene receptors. The bronchoconstriction caused by acetylcholine can be reverses by the antimuscarinic agent, ipratropium, and that caused be leukotrienes by the leukotrience receptor antagonist, montelukast. Both ipratropium and montelukast effectively produce bronchodilation (Figure 17.2).

Figure 17.2 Receptors on Bronchial Smooth Muscle