Which receptor subtype is commonly targeted to treat asthma due to bronchodilation effect?

Which receptor subtype is commonly targeted to treat asthma due to bronchodilation effect?

• A. Beta-1 receptors
• B. Beta-2 receptors
• C. Alpha-1 receptors
• D. Alpha-2 receptors

Answer: (B)

Bronchodilation in asthma is achieved by stimulating beta-2 adrenergic receptors on airway smooth muscle. When these receptors are activated, they trigger a cascade that increases cyclic AMP, which relaxes the smooth muscle and widens the airways. That's why beta-2 agonists are used as treatments to relieve bronchospasm, delivered by inhalation for quick relief or as maintenance therapy. The other receptor types don’t produce this airway relaxation. Beta-1 receptors are mainly in the heart and increase heart rate and contractility if stimulated. Alpha-1 receptors cause vasoconstriction, which isn’t helpful for opening the airways. Alpha-2 receptors regulate neurotransmitter release rather than causing bronchial smooth muscle relaxation.

Bronchodilation in asthma is achieved by stimulating beta-2 adrenergic receptors on airway smooth muscle. When these receptors are activated, they trigger a cascade that increases cyclic AMP, which relaxes the smooth muscle and widens the airways. That's why beta-2 agonists are used as treatments to relieve bronchospasm, delivered by inhalation for quick relief or as maintenance therapy.

The other receptor types don’t produce this airway relaxation. Beta-1 receptors are mainly in the heart and increase heart rate and contractility if stimulated. Alpha-1 receptors cause vasoconstriction, which isn’t helpful for opening the airways. Alpha-2 receptors regulate neurotransmitter release rather than causing bronchial smooth muscle relaxation.