Thromboxane A2 (TXA2) is a potent vasoconstrictor and activator of platelet aggregation. TXA2 elicits its effects via a 7-transmembrane domain G protein-coupled receptor, the TP receptor.{3168} The TP receptor is highly expressed in platelets and is relatively less abundant in tissues such as lung, kidney, brain, spleen, thymus, monocytes, uterus, and placenta.{3167,11368,2061,4311} The apparent molecular weight for TP receptors has been reported from 37 kDa to 70 kDa, depending on different degrees of glycosylation.{4311,8380,7235} However Cayman’s antibody consistently detects the TP receptor at 55 and 64 kDa in platelet, kidney, and Cos-7 cell samples. Cayman Chemical’s TP receptor polyclonal antibody can be used for western blot and immunocytochemical analysis for both the TPA and TPB splice variants of the receptor on samples of human, murine, rat, and COS-7 (African green monkey) origin.