<unk> A4 Note the four double bonds, three of them conjugated. This is a common property of A4, B4, C4, D4, and E4.<unk> B4<unk> C4 is a cysteinyl<unk> , as are D4 and E4.<unk> D4<unk> E4<unk> s are a family of eicosanoid inflammatory mediators produced in leukocytes by the oxidation of arachidonic acid (AA) and the essential fatty acid eicosapentaenoic acid (EPA) by the enzyme arachidonate 5-lipoxygenase.<unk> s use lipid signaling to convey information to either the cell producing them (autocrine signaling) or neighboring cells (paracrine signaling) in order to regulate immune responses. The production of<unk> s is usually accompanied by the production of histamine and prostaglandins, which also act as inflammatory mediators. One of their roles (specifically,<unk>  D4) is to trigger contractions in the smooth muscles lining the bronchioles; their overproduction is a major cause of inflammation in asthma and allergic rhinitis.<unk>  antagonists are used to treat these disorders by inhibiting the production or activity of<unk> s.
Leukotriene
Antileukotriene
Tocotrienol
Histamine
Nitric oxide
Interleukin
Prostaglandin
Allethrins