Table 1 Mechanisms of airway narrowing and hyper-responsiveness in asthma2
From: Is there a rationale and role for long-acting anticholinergic bronchodilators in asthma?
Process | Consequence |
|---|---|
Increased volume and/or contractility of airway smooth muscle cells | Excessive contractility of airway smooth muscle |
Secretion of multiple bronchoconstriction mediators such as histamine, prostaglandin D2 and neurotransmitters | Airway smooth muscle contraction |
Uncoupling of airway smooth muscle contraction as a result of inflammatory changes in the airway wall | Excessive narrowing of the airways; loss of maximum plateau of contraction when a bronchodilator is administered |
Oedema due to microvascular leakage in response to inflammatory mediators and structural changes to airway smooth muscle | Thickening of airway wall; amplification of airway narrowing due to contraction of airway smooth muscle for geometric reasons |
Sensitisation of sensory nerves leading to afferent activity and autonomic reflex | Increased parasympathetic, cholinergic and airway smooth muscle tone, with consequent exaggerated bronchoconstriction in response to sensory stimuli |
