Effect of a 2-h hypoxia on endothelial cells. Extracellular ATP (A) and adenosine (B) concentrations are expressed in nM, during hypoxia (T0–T120) and at re-oxygenation (T135–T240). Overexpression of mRNA for P2Y6 (C) and P2Y11 (D) receptors, adenosine receptors A2A (E), A2B (F), and ectonucleotidases CD39 (G) and CD73 (H) expressed with normalized mRNA levels using the following formula: 2−ΔΔCT as a function of time. Relative expression of cleaved caspase 3 by immunoblotting during hypoxia (I). Results are expressed as means ± sem (n = 6/group). #: p < 0.05, ##: p < 0.01, ###: p < 0.001 compared to T0 group.