The prostacyclin receptor, also termed the prostaglandin I 2 receptor or just IP, is a receptor belonging to the prostaglandin (PG) group of receptors. IP binds to and mediates the biological actions of prostacyclin (also termed prostaglandin I 2, PGI 2, or when used as a drug, epoprostenol). IP is encoded in humans by the PTGIR gene.

A long-acting and highly selective prostacyclin receptor agonist prodrug, 2-{4-[(5,6-diphenylpyrazin-2-yl) (isopropyl)amino]butoxy}-N-(methylsulfonyl)acetam ide (NS-304), ameliorates rat pulmonary hypertension with unique relaxant responses of its active form, {4-[(5,6-diphenylpyrazin-2-yl) (isopropyl)amino]butoxy}acetic acid (MRE-269), on rat ...

Combined with molecular docking and functional studies, our structures provide insight into agonist selectivity, ligand recognition, receptor activation, and G protein coupling. Our results provide a structural template for further improving IP-targeting drugs to reduce off-target activation of prostanoid receptors and adverse effects.

In a phase 2 trial, selexipag, an oral selective IP prostacyclin-receptor agonist, was shown to be beneficial in the treatment of pulmonary arterial hypertension.

Their binding profile and corresponding biochemical cellular responses on human prostanoid receptors expressed in cell lines, have now been compared. Iloprost had high binding affinity for EP1 and IP receptors (Ki 1.1 and 3.9 nM, respectively), low affinity for FP, EP3 or EP4 receptors, and very low affinity for EP2, DP1 or TP receptors.