[Ca2+]i measurements based on the fura-2 AM ratiometric dye (i) in control conditions, (ii) during 8 min chemically induced hypoxia (CIH), and (iii) following 8 min reoxygenation. KB-R7943 (5 μm), a Na+–Ca2+ exchanger inhibitor, was applied during CIH and reoxygenation or during reoxygenation only. All solutions contained 5 mm [K+]o. * P < 0.05 vs. Control, n = 6 experiments, 2–5 cells per experiment.