Pluronic® F-68 inhibits agonist-induced platelet aggregation in human whole blood in vitro

The effects have been studied of Pluronic(R) F-68 at 0.04% (w/v) on platelet aggregation in hirudin (50 mu g ml(-1))-anticoagulated, human whole blood in vitro in response to the following aggregation agonists: (i) phorbol 12-myristate 13-acetate (PMA; 0.05, 0.1 or 0.15 mu g,,ml(-1)), (ii) collagen (0.125, 0.25 or 0.5 mu g ml(-1)), or (iii) ristocetin (0.3, 0.6 or 1.2 mu g ml(-1)). Pluronic(R) F-68 significantly (P<0.05) inhibited platelet aggregation that followed the addition of all agonists at their lowest concentration tested. Pluronic(R) F-68 had markedly less pronounced inhibitory effects on the platelet aggregation that occurred in response to 0.15 mu g ml(-1) PMA, where the mean % aggregation after 8 min was 67% of control (P<0.05). Pluronic(R) F-68 did not alter platelet aggregation in blood treated with 0.25 or 0.5 mu g ml(-1) of collagen.