P2X7 purinoceptor expression in <i>Xenopus</i> 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.