Aspirin Intolerance: Experimental Models for Bed-to-Bench

Yamashita, Masamichi

Arachidonic acid is also metabolized to leukotriene A 4 (LTA 4 ) by another pathway involving 5-lipoxygenase (5-LOX), after which LTA 4 is converted to LTB 4 and LTC 4 . Then LTC 4 is metabolized to LTD 4 , and LTE 4 as shown in Fig. (2) . LTC 4 , LTD 4 , and E 4 contain cysteine residues, and thus are called cysteinyl leukotrienes (cysLTs). Cysteinyl LTs were originally discovered as slow reacting substance of anaphylaxis (SRS-A), which was extracted from the lung tissues of antigen-sensitized guinea pigs, and was shown to constrict airway smooth muscle from these animals more potently, slowly, and continuously than histamine via an antihistamine-resistant mechanism [37] .