Prostaglandin E2 (PGE2) activates four E prostanoid (EP) receptors, EP1-4. EP4 is a Gs protein-coupled receptor that, by elevating the second messenger cAMP, plays important roles in bone formation and resorption, cancer, and atherosclerosis. CJ-023423 is a potent and selective antagonist of the EP4 receptor (Ki = 13 and 20 nM for human and rat EP4, respectively). It inhibits PGE2-evoked elevation in intracellular cAMP in cells and, in vivo, reduces thermal hyperalgesia induced by intraplantar injection of PGE2. CJ-023423 reduces acute and chronic inflammatory pain in different mouse models.
