binding to and stimulating TP are TXA2=PGH2>>PGD2=PGE2=PGF2α=PGI2 (http://www.guidetopharmacology.org/GRAC/ObjectDisplayForward?objectId=346&familyId=58&familyType=GPCR). In addition to PGH2, several isoprostanes have been found to be potent stimulators of and to act in part through TP. The TP receptor is expressed in most human cells types as two alternatively spliced isoforms, TP receptor-α and TP receptor β, which differ in the length of their C-terminus tail; these isoforms communicate with different G proteins, undergo heterodimerization, and thereby result in different changes in intracellular signaling (only the TP receptor α is expressed in mice). Activation of TP by TXA2 or isoprostanes is associated with pro-inflammatory responses in cells, tissues, and animal models. TP activation is also associated with the promotion of platelet aggregation and thereby blood clotting and thrombosis. References External links G protein-coupled receptors