F2R and endothelial dysfunction: PAR-1 is the most prominent receptor for thrombin in endothelial cells in both mice and humans (O'Brien et al., 2000; Minami et al., 2004; Kataoka et al., 2003), and signaling through PAR-1 is a well-studied cause of blood endothelial dysfunction (Colotta et al., 1994; Rabiet et al., 1994; Rabiet et al., 1996; Kaplanski et al., 1998; Marin et al., 2001; Miho et al., 2005; Okada et al., 2006).