Fig. 5.

IVM potentiates the high-selectivity (I₁) but not the low-selectivity (I₂) state of the P2X₄ channel.A, Representative 3 μm ATP-evoked current from an oocyte expressing P2X₄ channels; the solid bar indicates the period of ATP application. B, Representative recording of a 3 μm ATP-evoked current during exposure to IVM (3 μm). C, Bar graph summarizing data from experiments such as those illustrated inA and B from seven cells; onlyI₁ is potentiated. D, Table showing reversal potentials for control and IVM-potentiatedI₁ in both Na⁺ and NMDG⁺ solutions, as well as the ratio of NMDG⁺ to Na⁺ permeability (n = 5). The NMDG⁺ reversal potential for I₂ is typically −30 mV (Khakh et al., 1999).