Figure 4.

Influence of Ir-3 on cytotoxicity, LDH release and cyclic nucleotide formation in human platelets. (A) Washed platelets were pre-incubated with the solvent control (0.1% DMSO) or Ir-3 (100 µM) for 10 min and subsequently washed two times with Tyrode's solution. Collagen (1 µg/ml) was then added to trigger platelet aggregation. (B) Washed platelets (3.6×10⁸/ml) were pre-incubated with the solvent control (0.1% DMSO) or Ir-3 (20, 50, and 100 µM) for 20 min, and a 10-µl aliquot of the supernatant was deposited on a Fuji Dri-Chem slide LDH-PIII. For other experiments, washed platelets (3.6×10⁸ cells/ml) were pre-incubated with (C) 1 µM PGE₁, (D) 10 µM NTG, or Ir-3 (20 µM) in the absence or presence of 100 µM SQ22536 or 10 µM ODQ, and were subsequently treated with 1 µg/ml collagen to induce platelet aggregation. Data are presented as the mean ± standard error of the mean (n=3). Profiles in sections A, C and D represent the four independent experiments. LDH, lactate dehydrogenase; PGE₁, prostaglandin E₁; NTG, nitroglycerin; ODQ, 1H-[1,2,4] oxadiazolo[4,3-a]quinoxalin-1-one.