The reported effects of tiotropium on airway smooth muscle mass suggest that in addition to relieving functional obstruction, anticholinergics may play an important role in reversing airways remodeling.
Evidence suggesting that nitrergic parasympathetic nerves are dysfunctional in airways disease is circumstantial but compelling.
In humans and in many animal species, adrenergic nerves are sparse or absent in the airways and
without apparent influence over airway smooth muscle tone .