All of the following are true regarding about Arachidonic acid (AA) pathway, except:
Cellular phospholipases, mainly phospholipase A2, release arachidonic acid (AA) from membrane phospholipids. Activation of phospholipase A2 is triggered by increase in cytosolic Ca2+ and activation of various kinases in response to external stimuli. Cyclo-oxygenase inhibitors such as aspirin, indomethacin inhibit activity of cyclo-oxygenase involved in conversion of AA into prostaglandins. Leukotriene A4, B4 cause chemotaxis. Leukotrienes C4 and D4 cause vasoconstriction and increase vascular permeability. Leukotrienes C4, D4, E4 are SLOW REACTING SUBSTANCE OF ANAPHYLAXIS (SRS-A). Action Examples Vasodilation PGI2, PGE1, PGE2, PGD2 Vasoconstriction Thromboxane A2, leukotriene C4, D4, E4 Increase vascular permeability Leukotriene C4, D4, E4 Chemotaxis, leukocyte adhesion Leukotriene B4 Smooth muscle contraction PGC4, PGD4, PGE4
Aspirin inhibits arachidonic acid pathway
Cytosolic Ca2+ leads to activation of membrane phospholipase A2
Action of phospholipase A2 causes synthesis of arachidonic acid
Leukotrienes C4, D4 cause vasodilation
Arachidonic acid metabolites