Leukotriene D4-Induced Signalling Events in Human Epithelial Cells: Gαi3 Activation and Translocation
Leukotrienes (LTs) are arachidonic acid derivatives that are known to mediate inflammatory reactions1, 2. LTs have been recognized as potent mediators of vaso- and bronchoconstriction, mucus secretion and smooth muscle contraction3, and they have been implicated in the pathogenesis of several conditions, e. g. chron’s disease, ulcerative colitis and bronchial asthma3–5. LTs exert their effects by binding to receptors on the plasma membranes of their target cells1, 2, 6. Radioligand experiments6 and functional analyses using specific inhibitors have revealed the presence of LT receptors on a large number of cell types. The functional analyses have indicated the existence of at least two subsets of cysteinyl leukotriene receptors (CysLT receptors), for which a classification was quite recently published7. It has been shown that LTD4 induces a rise in the cytosolic free Ca2+ concentration in different types of cells8, 9, and we found that that effect can be blocked by pretreating cells with ICI-198,615 (unpublished data). The G-protein responsible for the influx of Ca2+ is sensitive to pertussis toxin (PTX), whereas the one responsible for mobilisation of intracellular Ca2+ is rho dependent10.
KeywordsPertussis Toxin Human Epithelial Cell Guanosine Triphosphate CysLT Receptor Guanosine Diphosphate
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