LY-255283 is a tetrazole derivative that acts as the competitive antagonist of the Leukotriene B4 (LTB4) receptor 2 (BLT2). LY255283 shows potent inhibition of LTB4 binding to human neutrophils and of LTB4-induced aggregation of guinea-pig neutrophils. In guinea-pigs, this compound also suppressed both specific binding of LTB4 to lung membrane and LTB4-induced contraction of lung parenchyma. Intravenous and oral administration of LY255283 dose-dependently reduced airway obstruction in guinea-pigs induced by LTB4, but not by histamine and U- 46619. Antigen-induced lung eosinophilia in rats was inhibited by orally administered LY255283. LY255283 exhibited the ability to suppress the shock induced by endotoxin and splanchnic artery occlusion in rats. LY255283 (bolus i.v. and subsequent infusion) attenuated endotoxin-induced adult respira¬tory distress syndrome in the pig model. LY255283 is used in leukotriene receptor research along with other selective leukotriene receptor agonists and antagonist to identify and differentiate the physiological and cell signaling effects of the leukotriene B4 receptor on processes such as paclitaxel resistance in MCF-7/DOX breast cancer cells, monocyte-derived dendritic cell chemotaxis, and 5-lipoxygenase activity and interleukin-8 production in human neutrophils.