Hypoxia increases cytosolic free calcium in porcine pulmonary arterial endothelial cells

Summary Alteration of cytosolic free calcium (Ca²⁺ ₁]) in hypoxia was studied with fluorescent probe, Fura-2 in cultured porcine pulmonary arterial endothelial cells. It was found that hypoxia caused by bubbling the cell suspension with 100% N₂ increased Ca²⁺ ₂] in endothelial cells by 90±20% (n=8,P<0.05), but didn’t affect that in a Ca²⁺-free buffer, La³⁺ (2×10⁻⁵ mol/L) inhibited the hypoxia-induced increment in Ca²⁺]₁, whereas verapamil (10⁻⁸ mol/L) didn’t. These findings suggest that hypoxia could induce Ca²⁺ influx in pulmonary arterial endochelial cells, which might play an important role in vascular response to hypoxia.