FIGURE 3.

Activation of ASIC3 channels by AMI is determined by residues (Glu-79 and Glu-423) of the nonproton ligand sensing domain. A, representative current traces illustrating the effects of E79A and E423A mutations on 1 and 3 mm AMI-induced currents. B, pooled data from experiments as in A and similar results from other mutations of Glu-79 or Glu-423. Data points are means ± S.E. of four to seven measurements normalized to the pH 5.0-induced peak currents. Note: for most mutations, the maximal pH 5.0-induced currents were generated following pH 9.0 pretreatment to restore the steady-state desensitization of acid-dependent currents at pH 7.4. *, p < 0.05 versus wild-type (WT). The dashed line represents the current amplitude induced by AMI (3 mm) from WT ASIC3 channels. C, ratio of current amplitude induced by 1 mm AMI to that by 3 mm AMI. The data were generated from B and are means ± S.E. *, p < 0.05 versus WT (dashed line).