Leukotriene

[4] One of their roles (specifically, leukotriene 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.

[6] The name leukotriene, introduced by Swedish biochemist Bengt Samuelsson in 1979, comes from the words leukocyte and triene (indicating the compound's three conjugated double bonds).

What would be later named leukotriene C, "slow reaction smooth muscle-stimulating substance" (SRS) was originally described between 1938 and 1940 by Feldberg and Kellaway.

[7][8][9] The researchers isolated SRS from lung tissue after a prolonged period following exposure to snake venom and histamine.

Its primary function is to recruit neutrophils to areas of tissue damage, though it also helps promote the production of inflammatory cytokines by various immune cells.

The catalytic mechanism involves the insertion of an oxygen moiety at a specific position in the arachidonic acid backbone.

[citation needed] The cysteinyl-leukotrienes act at their cell-surface receptors CysLT1 and CysLT2 on target cells to contract bronchial and vascular smooth muscle, to increase permeability of small blood vessels, to enhance secretion of mucus in the airway and gut, and to recruit leukocytes to sites of inflammation.

The levels of cysteinyl leukotrienes, along with 8-isoprostane, have been reported to be increased in the EBC of patients with asthma, correlating with disease severity.

[21] Leukotrienes are found to play an important role in the later stages of Alzheimer's disease and related dementias in studies with animals.