Ecosanoids

1. It includes prostaglandins, prostacyclin, thrombaxne, leukotriens and lipoxins.

2. They are derived from 20 carbon polyunsaturated fatty acids called eicosanoic acids which are essential fatty acids or their derivatives. Eg. Linoleic acid, Arachidonic acid, linoleic acid.

3. In human body group-2 eicosanoids derived directly from arachidonic acid are most prevalent.

Functions of eicosanoids:

1.      Excess prostaglandin causes pain, inflammation, fever, nausea, vomiting.

2.      TX A₂ causes platelet aggregation, vasoconstriction, smooth muscle contraction.

3.      PG I₂ causes inhibition of platelet aggregation, vasodilation.

4.      PG E₂ causes vasodilatation,  smooth muscle relaxation, uterine contraction, inhibition of HCL secretion by parietal cell, renal vasodilatation and natriuresis.

5.      PG F₂ causes vasoconstriction, smooth muscle contraction, uterine contraction.

6.      Leukotrienes causes regulation of the events of inflammation, hypersensitivity and anaphylaxis, Vasoconstriction and smooth muscle contraction, increased vascular permeability and chemotaxis., increased vascular permeability and chemotaxis.