Thrombin receptor antagonists: a work in progress.

The thrombin receptor and protease-activated receptor 2 (PAR-2) are the two currently known members of the large family of G protein-coupled receptors that are activated by proteases. Both receptors are located on cells in and around the vascular space, including platelets, endothelial cells, vascular smooth muscle cells, fibroblasts and some lymphocytes. This brief review summarizes current information on thrombin receptors and focuses on some of the issues that are relevant for ongoing efforts to develop thrombin receptor antagonists.