Pharmacology · single question
Increased mucous secretions during acute asthma are caused by:
Show answer and explanation
Correct answer: C. Acetylcholine release (parasympathetic stimulation)
- A. Incorrect. Serotonin (5-HT) plays a minor role in bronchoconstriction but is not the primary cause of increased mucous secretion in acute asthma.
- B. Incorrect. Norepinephrine (adrenergic) stimulation causes bronchodilation and reduced secretions — it is therapeutically beneficial in asthma.
- C. Correct. Parasympathetic (cholinergic) stimulation via ACETYLCHOLINE acting on muscarinic receptors is the PRIMARY cause of increased mucus secretion and bronchospasm in asthma. This is why anticholinergic drugs (ipratropium) are used as bronchodilators — they block ACh-mediated mucus secretion and bronchospasm.
- D. Incorrect. Histamine causes bronchoconstriction and vasodilation, but the primary driver of mucus hypersecretion specifically is cholinergic (parasympathetic) stimulation.