An essential, unsaturated, 20 carbon fatty acid that humans use to synthesize regulatory molecules such as prostaglandins and thromboxanes.
As the mast cell is activated, several other events occur that contribute to the pathophysiology of allergic diseases. One such event is the activation of a membrane enzyme called phospholipase A2 , which breaks down membrane components to arachidonic acid . Arachidonic acid is further metabolized by one of two enzyme pathways into various prostaglandins (by cyclooxygenase) or leukotrienes (by lipooxygenase). Both prostaglandins and leucotrienes are highly pro-inflammatory, bronchospastic and vasodilatory .