Related Experiment Video
Updated: May 26, 2026

In vitro Measurements of Tracheal Constriction Using Mice
Published on: June 25, 2012
Muscarinic receptor antagonists: effects on pulmonary function
Kalmia S Buels1, Allison D Fryer
1Oregon Health and Science University, 3181 SW Sam Jackson Park Road, UHN67, Portland, OR 97239, USA. buelsk@ohsu.edu
Abstract:
In healthy lungs, muscarinic receptors control smooth muscle tone, mucus secretion, vasodilation, and inflammation. In chronic obstructive pulmonary disease (COPD) and asthma, cholinergic mechanisms contribute to increased bronchoconstriction and mucus secretion that limit airflow. This chapter reviews neuronal and nonneuronal sources of acetylcholine in the lung and the expression and role of M₁, M₂, and M₃ muscarinic receptor subtypes in lung physiology. It also discusses the evidence for and against the role of parasympathetic nerves in asthma, and the current use and therapeutic potential of muscarinic receptor antagonists in COPD and asthma.
Related Concept Videos
Antiasthma Drugs: Muscarinic Receptor Antagonists
Antimuscarinic agents compete with ACh for the same binding site on the muscarinic receptors. By binding to these receptors, they inhibit the downstream effects of ACh and block the parasympathetic...
Cholinergic Antagonists: Pharmacological Actions
Gastrointestinal Effects: Antimuscarinics reduce gut contractions, increase gastric emptying, and slow intestinal transit. They partly inhibit gastric acid secretion...
Cholinergic Antagonists: Therapeutic Uses
Respiratory Tract: Ipratropium, aclidinium, and tiotropium treat asthma, chronic bronchitis, and chronic obstructive pulmonary disease (COPD). They protect against bronchoconstriction caused by irritants like cigarette smoke, sulfur dioxide, and ozone. They also help reduce nasopharyngeal secretions in common...
Cholinergic Antagonists: Pharmacokinetics
Direct-Acting Cholinergic Agonists: Pharmacological Actions
Cholinergic Antagonists: Chemistry and Structure-Activity Relationship

