Prostanoid Receptors

Prostanoid receptors are activated by the endogenous ligands prostaglandin (PG) D₂, PGE₂, PGF_2α, PGH₂, prostacyclin (PGI₂) and thromboxane A₂. Cyclooxygenase (COX) converts arachidonic acid to PGH₂, from which the other prostaglandins are synthesized. Prostanoid receptors are a family of nine G-protein-coupled receptors that have distinct tissue distributions and actions.

1. DP receptors (DP_1-2) are coupled to G_αs. They are expressed in the small intestine, lung, stomach and uterus. Activation of DP₁ results in inhibition of platelet activation and vasodilation; they are also involved in sleep regulation. DP₂ activation leads to immune cell activation.
2. EP receptors (EP_1-4) are a diverse group of prostanoid receptors. EP₁ receptors are restricted to the kidney, lung and stomach, and induce smooth muscle contraction. EP₂ and EP₄ couple to G_αs and induce smooth muscle relaxation. EP₃ is an inhibitory receptor that prevents smooth muscle relaxation.
3. FP receptors are coupled to G_αq. They are abundant in the corpus luteum, where they are involved in luteolysis.
4. IP receptors are coupled to G_αs and are involved in pain mediation, relaxation of vascular smooth muscle, inhibition of platelet aggregation and they contribute to cardiovascular health.
5. TP receptors can be coupled to both G_αq and G_αi. They are expressed abundantly in highly vascular tissues such as the kidney and heart, and immune-related organs such as the thymus and spleen. They mediate smooth muscle contraction and platelet aggregation.

External sources of pharmacological information for Prostanoid Receptors :

• IUPHAR Receptor Code

• BJP Guide

Prostanoid Receptor Gene Data

Pathway of Prostanoid Production

Prostanoid Receptor Pharmacological Data

References

IUPHAR Compendium of receptor characterization and classification. (2000) 2nd Edition. IUPHAR Media. Breyer et al (2001) Prostanoid receptors: subtypes and signaling. Ann.Rev.Pharmacol.Toxicol. 41 661.