FIG. 1.

Canonical and noncanonical mechanisms of traumatic brain injury induced pulmonary dysfunction. The canonical pathway (green rectangles) described for traumatic brain injury-induced effects in the lung depends on the release of catecholamines, which enter the bloodstream and cause elevated pulmonary capillary pressures and permeability. Fluid is able to cross capillary endothelial cells causing pulmonary edema. The noncanonical pathway (blue rectangles) for the effects of traumatic brain injury on pulmonary function involves the release of damage-associated molecular patterns (DAMPs) by injured or dead neurons, which then enter venous blood in the lungs via the pulmonary circulation and cause pulmonary injury and dysfunction. To see this illustration in color, the reader is referred to the web version of this article at www.liebertpub.com/ars