Submitted on June 4, 2007
Revised on August 15, 2007
Alveolar Epithelial 
2-Adrenergic Receptors
Gokhan M Mutlu1* and Phillip Factor2
1 Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA,
2 Department of Pulmonary, Allergy and Critical Care Medicine, Columbia University College of Physicians and Surgeons, New York, NY, USA
* To whom correspondence should be addressed. E-mail: g-mutlu{at}northwestern.edu.
2-adrenergic receptors are present throughout the lung including the alveolar airspace where they play an important role for regulation of the active Na+ transport needed for clearance of excess fluid out of alveolar airspace. 2-adrenergic receptor signaling is required for upregulation of alveolar epithelial active ion transport in the setting of excess alveolar edema. The positive, protective effects of 2-adrenergic receptor signaling on alveolar active Na+ transport in normal and injured lungs provide substantial support for the use of 2-adrenergic agonists to accelerate alveolar fluid clearance in patients with cardiogenic and non-cardiogenic pulmonary edema. In this review, we summarize the role of 2-adrenergic receptors in the alveolar epithelium with emphasis on their role in regulation of alveolar active Na+ transport in normal and injured lungs.
