Essential fatty acid interactions: Difference between revisions

Revision as of 16:29, 31 January 2007

Revision as of 16:33, 31 January 2007

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Eicosanoid signaling paths are complex.

It is therefor difficult to characterize the action any particular eicosanoid.

For example, PGE₂ binds four receptors, dubbed EP1EP_1–4.

Each is coded by a separate gene, and some exist in multiple [[isoform]]s.

Each EP receptor in turn couplecouples to a [[G protein]].

The EP₂, EP₄ and one isoform of the EP₃ receptors couple to G_s.

This increases intracellular [[Cyclic adenosine monophosphate|cAMP]] and is anti-inflammatory.
EP₁ and other EP₃ isoforms couple to G_q.

This leads to increased intracellular calcium and is pro-inflammatory.

Finally, yet another EP₃ isoform couples to G_i, which both decreases cAMP and increases calcium.
Many immune-system cells express multiple receptors that couple these apparently opposing pathways.<ref name=Tilley />

Presumably, EPA-derived PGE3PGE₃ has a somewhat different effect of on this system, but it is not well-characterized.

==The arachidonic acid cascade in the central nervous system (CNS)==