Effects of arachidonic acid metabolites on airway sensors

Arachidonic acid (AA) in the cell membrane produces a variety of metabolites by different enzymatic pathways. These lipid metabolites, along with other mediators, play an important role in the inflammatory processes. Many of them can bind directly to the receptors on the sensory endings and initiate electrical impulses to be transmitted to the central nervous system, causing reflex responses. These bioactive AA metabolites may also alter the lung mechanics (mechanical environment of the sensory ending), and in turn, stimulate sensory afferents. In addition, some metabolites may sensitize the sensory endings and make them more responsive to other mechanical or chemical stimulation. These metabolites may also induce other mediators and modulators to cause physiological effects. Furthermore, some of them may attract inflammatory cells to produce a localized effect. In short, AA metabolites may come from different sources and act through multiple pathways to stimulate airway sensors. This brief review is intended to illustrate the underlying mechanisms and help elucidate the inflammatory process in the airways.