The characterization of the substitution-normal mutants of P2X4R. a Example records of 10 μM ATP-induced currents in the presence of 3 μM IVM for the Y195A/S, F200A/S, and F330A/S mutants. b Concentration–response curves of IVM deactivation for the WT (n = 10), Y195A (n = 6), F200A (n = 7), and F330A (n = 5) receptor. c Concentration–response curves of IVM potentiation for the WT (n = 10), Y195A (n = 6), F200A (n = 7), and F330A (n = 5) receptor