The GPIIbIIIa antagonist drugs eptifibatide and tirofiban do not induce activation of apoptosis executioner caspase-3 in resting platelets but inhibit caspase-3 activation in platelets stimulated with thrombin or calcium ionophore A23187.

Reagents and solutions Integrilin (eptifibatide, 0.75 mg/mL) was purchased from Millennium Pharmaceuticals Inc. (Cambridge, MA) and Aggrastat (tirofiban hydrochloride, 50 μg/mL) was from Medicure Pharma Inc. (Somerset, NJ). Gly-Pro-ArgPro (GPRP) peptide was purchased from Sigma (St. Louis, MO), human α-thrombin was from Haematologic Technologies Inc (Crossing, VT), A23187 was from Calbiochem (San Diego, CA) and FAM-DEVD-FMK (carboxyfluorescein-carbonyl-aspartyl-glutamyl-valyl-aspartic acid fluoromethyl ketone) was from Chemicon International (Temecula, CA). Control diluent buffer A was composed of phosphate buffered saline (Invitrogen, Carlsbad, CA) supplemented with 1 mM MgCl2, 5.6 mM glucose, 0.1% BSA and 10 mM HEPES, pH 7.4.