Leukotriene C4 (LTC4) is the parent cysteinyl-leukotriene produced by the LTC4 synthase-catalyzed conjugation of glutathione to LTA4. LTC4 is produced by neutrophils, macrophages, and mast cells, and by transcellular metabolism in platelets. It is one of the constituents of slow-reacting substance of anaphylaxis (SRS-A) and exhibits potent smooth muscle contracting activity. LTC4-induced bronchoconstriction and enhanced vascular permeability contribute to the pathogenesis of asthma and acute allergic hypersensitivity. The concentration of LTC4 required to produce marked contractions of lung parenchymal strips and isolated tracheal rings is about 1 nM. LTC4 methyl ester is a more lipid soluble form of LTC4. The biological activity of LTC4 methyl ester has not been reported.
The endocannabinoids, 2-arachidonoyl glycerol (2-AG) and arachidonoyl ethanolamide (AEA), are biologically active lipids that regulate diverse neurological and metabolic functions by activating the cannabinoid receptors, central cannabinoid (CB1) and peripheral cannabinoid (CB2). Monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH) hydrolyze 2-AG and AEA, respectively, thus terminating their biological function. IDFP is an organophosphorus compound that dually inhibits MAGL and FAAH with IC50 values of 0.8 and 3 nM, respectively. At 10 mg/kg, IDFP elevates brain levels of 2-AG and AEA more than 10-fold, and decreases levels of arachidonic acid by a similar magnitude.