Jerome Coste website

MASTER Master 2 (Cellular and Molecular Biology) | + | J. Fourier University, Master 2

Relations between metabolism and regulation of the intracellular oxygen partial pressure.

Toward an intracellular mapping of oxygen. ≡

(Laboratory of Fondamental and Applicated Biology, Molecular Electrophysiology Group; Grenoble 1 University - 2000).

Abstract

We have developed a new phosphorescent probe, PdTCPPNa4, whose luminescence properties are affected by local variations of intracellular oxygen tension (PO₂).

Spectrofluorometric measurements on living human umbilical venous endothelial cells loaded with this molecule show that a decrease in extracellular oxygen tension induces a decrease of PO₂, illustrating the phenomenon of oxygen diffusion and validating the use of this probe in living cells. Moreover, KCN- or 2,4-dinitrophenol-induced modifications of respiration do not lead to detectable PO₂ variations, probably because O₂ diffusion is sufficient to allow oxygen supply.

On the contrary, activation by acetylcholine or endothelial nitric oxide synthase (eNOS), which produces NO while consuming oxygen, induces a significant decrease in PO₂, whose amplitude is dependent on the acetylcholine dose, i.e., the eNOS activity level. Hence, activated cytosolic enzymes could consume high levels of oxygen which cannot be supplied by diffusion, leading to PO₂ decrease.

Other cell physiology mechanisms leading to PO₂ variations can now be studied in living cells with this probe.