Fig. 5.
Loss of pinacidil sensitivity in Kir6.1/SUR2B[R1154Q Cantú mutant channels. (A) Representative whole-cell patch-clamp recordings from stably transfected WT and R1154Q mutant channels exposed to nonconducting (high Na), basal (high K), pinacidil-activated (Pin), and glibenclamide-inhibited (Glib) at concentrations indicated. (B) Nonstationary noise analysis (see Materials and Methods) for the two traces in (A), during exposure to basal, Pin, or Pin+Glib conditions as indicated by colored circles. (C) Number of channels per cell from experiments as in (A) and (B). (D) Open probability from experiments as in (A) and (B) during the final ∼30 seconds in each condition. (E) Ratio of the current in pinacidil to the basal current (IPin/IBasal), and (F) ratio of the current in pinacidil+glibenclamide to the current in pinacidil (IPin+Glib/IPin) from experiments as in (A) and (B). In each of graphs in (C)–(F), data from individual experiments are plotted together with mean ± S.D. Statistical significance compared with the WT under each condition is denoted by ***P < 0.001 or *P < 0.05, according to one-way ANOVA test with Tukey’s multiple comparisons.