Cell experiment:

Vena8Fluoro+ Biochips are coated with collagen (200 μg/mL) at 4℃ overnight and thereafter blocked with bovine serum albumin (10 μg/mL) for 30 minutes at room temperature followed by washing steps. Whole blood collected in sodium citrate is incubated with 3, 3-dihexyloxacarbocyanine iodide (1 μM) in the dark for 10 minutes. PGD2 (30 nM), BW245c (3 nM) are added 10 min before the start of perfusion, and the DP antagonist BWA868c or Laropiprant (1 μM) are added 10 min before the agonists. In another set of experiments whole blood is treated with niacin (3 mM), acetylsalicylic acid (1 mM) or Laropiprant (1 μM and 10 μM) for 30 min. CaCl2 at a final concentration of 1 mM is added 2 minutes before the perfusion over the collagen-coated chip. Perfusion is carried out at a shear rate of 30 dynes cm2. Thrombus formation is recorded. Computerized image analysis is performed by DucoCell analysis software, where the area covered by the thrombus is calculated. Data are expressed as percent of area covered in a control sample[2].

Laropiprant is a potent, selective DP receptor antagonist with Ki values of 0.57 nM and 2.95 nM for DP receptor and TP Receptor, respectively.
Laropiprant is a potent, selective DP receptor antagonist with Ki values of 0.57 nM and 2.95 nM for DP receptor and TP Receptor, respectively.[1]. Laropiprant (1 μM) causes a significant inhibition of the aggregation but still counteractes the pronounced inhibition caused by PGD2 (30 nM) and BW245c (3 nM). Laropiprant blocks DP receptor-dependent increase in VASP phosphorylation, as well as inhibition of P-selectin expression, GPIIb/IIIa activation and in vitro thrombus formation. Laropiprant antagonizes the increased platelet aggregation by TP and EP3 receptor activation. Laropiprant (10 μM) and niacin inhibit in vitro thrombus formation[2].
Reference：
[1]. Sturino CF, et al. Discovery of a potent and selective prostaglandin D2 receptor antagonist, [(3R)-4-(4-chloro-benzyl)-7-fluoro-5-(methylsulfonyl)-1,2,3,4-tetrahydrocyclopenta[b]indol-3-yl]-acetic acid (MK-0524). J Med Chem. 2007 Feb 22;50(4):794-806.
[2]. Philipose S, et al. Laropiprant Attenuates EP3 and TP Prostanoid Receptor-Mediated Thrombus Formation. PLoS One. 2012;7(8):e40222.