Fig. 4.

Sensitivity of P2X₄₊₆ receptors to the agonist αβmATP. A, Differential αβmATP responsiveness measured in peak current amplitudes betweenXenopus oocytes expressing either P2X₄₊₆channels or P2X₄ at day 3 after injection; see Figure1B for comparison of ATP-induced peak currents.B, Normalized dose–response curves of P2X₄₊₆ and P2X₄ receptor species for αβmATP. Values are normalized to the response to 100 μm ATP; double asterisks denote significant difference; p < 0.01 (averages ± SEM from 5 to 8 oocytes per point in 2 independent experiments).