Figure 5.

Hesperetin (HSP) decreases cell Na⁺ load. (a,b) Effects of hesperetin (100 μmol·L⁻¹) on the inactivation time course of I _Na in the wild‐type (WT) and R1623Q channels. Current traces were normalized to peak amplitude in order to get a better comparison of the effects on I _Na inactivation. For the sake of clarity, only the first 20 ms of the current traces is shown. The dotted lines represent the fit of the inactivation phase of the current with a double‐exponential function with fast and slow components. (c,d) Effects of different concentrations of hesperetin on inactivation time constants of I _Na. *P < 0.05 compared with its own control and with WT, n = 12, two‐way ANOVA with Tukey's post hoc test. (e) Concentration‐dependent effects of hesperetin on the relative amplitude of the slow component of I _Na in the WT and R1623Q channels. Hesperetin significantly decreased the relative amplitude of the slow inactivation component. *P < 0.05 with respect to its own control, n = 12, one‐way ANOVA with Tukey's post hoc test. (f) hesperetin (100 μmol·L⁻¹) reduced the amount of transported Na⁺, during the flow of I _Na, in R1623Q to the same level as in WT under control condition. Current traces were integrated, and data were expressed as charge normalized to membrane capacitance (pC·pF⁻¹). *P < 0.05 with respect to its own control; ^§ P < 0.05 with respect to WT, n = 32, two‐way ANOVA with Tukey's post hoc test