LXR ligands diminished platelet aggregation and calcium mobilization stimulated by thrombin. Washed platelets were preincubated with GW3965, T0901317, or vehicle (DMSO 0.04% volume/volume) for 10 minutes and stimulated with thrombin for 360 seconds (A-C). (Ai,Bi) Representative aggregation traces of platelets treated with GW3965 (1-20μM) (Ai), T0901317 (10-50μM) (Bi), or vehicle followed by thrombin stimulation (0.03 U/mL). (Aii,Bii) Data are plotted as percentage of aggregation and represent mean values. (C) Aggregation traces of platelets stimulated by 0.04 U/mL (Ci) or 0.1 U/mL (Cii) thrombin after pretreatment with 20μM of GW3965 or DMSO. (Ciii) Inhibition of aggregation by 20μM GW3965 was measured over a range (0.03-1 U/mL) of thrombin. (D) Fluo-4NW-loaded platelets were incubated with GW3965 (20μM) or DMSO for 10 minutes and then stimulated with thrombin (0.08 U/mL) for 200 seconds, and intracellular mobilization of calcium measured by spectrofluorimetry. n ≥ 3. *P < .05. **P < .01.