2.

Reduction of ATP+TNF-α-induced apoptotic cell death by P2 receptor antagonists

	Apoptosis (% of ATP+TNF-α set to 100%± S.E.M.)
ATP+TNF-α	100.00±5.64
+ Suramin (100 μM)	33.52±6.85*
+ PPADS (100 μM)	49.3±2.1*§
+ RB2 (100 μM)	42.11±7.69*§

Murine cardiomyocytes were exposed to ATP (500 μM) in combination with TNF-α (10 ng/ml), together with the various P2 receptor antagonists (which were added 30 min before). At the end of the incubation period, the percentage of apoptotic death was evaluated by isotonic PI staining of nuclei (see Materials and methods), followed by flow cytometric analysis. ATP+TNF-α-induced apoptosis was set to 100%. The three antagonists had no effect on cell survival when utilized alone (data not shown). Data represent the mean ± S.E.M of three independent experiments.^*P<0.05 versus ATP+TNF-α, and §P<0.05 versus control, by one-way ANOVA (Scheffe's F test).