Fig. 2.

The N-termini P2X₁ receptor minigene blocks the potentiating effects of PMA and mGluR1α receptor stimulation on P2X₁ receptor currents. A minigene encoding the N-terminal sequence of the P2X₁ receptor was co-expressed with wild type P2X₁ and mGluR1α receptors in the Xenopus oocytes. (a) Upper left panels show representative currents evoked by a maximal concentration of ATP (100 μM, indicated by bar) at control oocytes (WT P2X₁) and those following 10 min incubation with PMA (100 nM). Right upper panels show the effects of co-expression of the amino terminal minigene (NH₂ minigene) on the effects of PMA. The bar chart shows summary data, n=6–7. (b) Upper panels show sample traces for a given oocyte co-expressing P2X₁ and mGluR1α receptors (left) or P2X₁ receptors, mGluR1α receptors and the P2X₁ receptor amino terminal minigene (right traces). Responses to a maximal concentration of ATP (100 μM, indicated by bar) are shown before and after the application of glutamate (100 μM). Glutamate evoked an inward calcium activated chloride current and potentiated subsequent ATP evoked responses. This potentiation was reduced by co-expression of the P2X₁ receptor N-terminal minigene. The bar chart shows a summary of the data, n=6–7. ***p< 0.001.