FIGURE 6.

Arg substitutions in the palm domain reduce the response to successive stimulations. A, representative recordings of experiments performed with oocytes expressing control (C70L) and mutant channels. B, upper panel, Q278R and L280R channels show reduced responses to successive stimulations. The relative response represents the ratio of the pH-elicited peak currents from two consecutive stimulations (n = 18–22). Statistically significant differences with the control are indicated: +, p < 0.001 (Kruskal-Wallis test followed by Dunn's multiple comparison test). Oocytes expressing C70L channels served as controls. Lower panel, time constants of desensitization of ASIC1a mutant channels. Whole-cell currents were fitted to a single exponential function as described under “Experimental Procedures” (n = 17–23).