Figure 3. Probenecid shows minimal inhibition of ATP-induced dye uptake in HEK-rat P2X7 and HEK-mouse P2X7 cells.

Ethidium⁺ uptake was induced in (A) rat P2X7 and (B) mouse P2X7 stable cell lines by the addition of 1 mM ATP (denoted by the arrow) in a low divalent physiological solution. Control ethidium uptake to ATP is shown in black squares and ethidium uptake in the presence of 2.5 mM probenecid (pre-incubated for 10 minutes at 37°C) is shown in red shapes.