What neurotransmitter is blocked by anticholinergic drugs to prevent bronchial constriction?

Anticholinergic drugs work primarily by blocking the action of acetylcholine, a neurotransmitter that plays a critical role in the parasympathetic nervous system, particularly in smooth muscle contraction and gland secretion.

In the context of bronchial constriction, acetylcholine is responsible for promoting airway narrowing by binding to muscarinic receptors on bronchial smooth muscle cells. By blocking these receptors, anticholinergic drugs effectively prevent bronchoconstriction and promote bronchodilation, making the airways more open. This mechanism is particularly useful in treating conditions like asthma and chronic obstructive pulmonary disease (COPD), where airway constriction can significantly impede breathing.

Understanding this interaction helps clarify the importance of acetylcholine in respiratory physiology and why targeting it with specific medications can alleviate symptoms associated with bronchial constriction.