P2X7 purinoceptor expression in Xenopus oocytes is not sufficient to produce a pore-forming P2Z-like phenotype

Abstract The purinergic rP2X7 receptor expressed in a number of heterologous systems not only functions as a cation channel but also gives rise to a P2Z-like response, i.e. a reversible membrane permeabilization that allows the passage of molecules with molecular masses of ≥300 Da. We investigated the properties of rP2X7 receptors expressed in Xenopus oocytes. In two-electrode voltage-clamp experiments, ATP or BzATP caused inward currents that were abolished or greatly diminished when NMDG + or choline + replaced Na + as the principal external cation. In fluorescent dye experiments, BzATP application did not result in entry of the fluorophore YO-PRO-1 2+ . Thus, rP2X7 expression in Xenopus oocytes does not by itself give rise to the pore-forming P2Z phenotype, suggesting that ancillary factors are involved.