The relative responsiveness of the wild type (WT) and selected rP2X4R mutants to P2XR agonist analogs.

ATP and agonists were applied in 100 µM concentrations for 2 s with a washing interval of 60 s. The data are the mean ± SEM, relative to ATP efficacy (100%), from 26 to 37 measurements for the WT receptor and from 3 to 18 measurements per mutant. Group I: Mutants that exhibited changes in ATP potency/efficacy, deactivation kinetics, and changes in the relative responsiveness to orthosteric analog agonists. Group II: Mutants that exhibited changes in ATP potency/efficacy and deactivation, but no changes in the relative responsiveness to analog agonists. Group III: Mutants that showed no significant changes in ATP potency/efficacy. The statistical significance was determined by an ANOVA comparing the responsiveness to agonists between WT and mutant receptors: **, pThe relative responsiveness of the wild type (WT) and selected rP2X4R mutants to P2XR agonist analogs.