Figure 4. Effect of ATP synthase blockade on [Ca²⁺]_i in type I cells.

Effects of hypoxia and oligomycin on [Ca²⁺]_i (measured using indo-1) in type I cells. A, effect of removing extracellular calcium after application of oligomycin. B, effect of removing extracellular calcium prior to and during the application of oligomycin. Note that in the presence of extracellular calcium oligomycin induced a large rise in [Ca²⁺]_i that was maintained following oligomycin removal. Removal of extracellular calcium prevented or reversed this oligomycin induced rise in [Ca²⁺]_i.