FIGURE 3.

Selective inhibition of P2X1 receptors by lipid raft disruption. Effects of lipid raft disruption by filipin (10 μm for 20 min) and mβ-CD (10 mm for 1h) were tested for currents mediated by P2X1, P2X2, P2X3, and P2X4 receptors expressed in HEK293 cells (panels a–d), respectively). α-CD (10 mm for 1 h) was used as an inactive analog of mβ-CD. Currents were evoked by fast application of ATP (100 μm) for 3 s with a U-tube application system. We compared the densities of the first currents in treated and nontreated cells (histograms on the right side of panels). Surface biotinylation revealed that treatment with filipin, α-CD, or mβ-CD does not change the surface expression of P2X1 receptors (panel a). **, p < 0.01; ***, p < 0.001.