Mechanism of Action of Long-Acting BronchodilatorsDeBellis, Ronald J. PharmD, FCCPClinical Pulmonary Medicine: July 2005 - Volume 12 - Issue 4 - p S10-S12 doi: 10.1097/01.cpm.0000170112.09340.1a Supplement Article Abstract In Brief Author Information It has been suggested that the pathophysiology of chronic obstructive pulmonary disease is characterized by a centrally mediated increase in cholinergic tone. β-Agonists act by binding to adrenergic receptors, which stimulate bronchodilation through the mediation of the cyclic AMP (cAMP) second messenger system. Theophylline is postulated to stimulate bronchodilation by inhibiting phosphodiesterase and adenosine. Phosphodiesterase inhibition prolongs the actions of cAMP and results in bronchodilation. Inhaled long-acting anticholinergics work by antagonizing the actions of acetylcholine, producing relaxation of airway smooth muscle. Describes mechanism of action of agents used to treat chronic obstructive pulmonary disease. From the Massachusetts College of Pharmacy and Health Sciences-Worcester, Worcester, MA. Correspondence: Ronald J. DeBellis, PharmD, Massachusetts College of Pharmacy and Health Sciences-Worcester, 19 Foster Street, Worcester, MA 01608. © 2005 Lippincott Williams & Wilkins, Inc.