Figure 7.

The function of the Na⁺, K⁺ ATPase, following pump reactivation, between experimental groups

A, when the Na⁺,K⁺‐ATPase was inhibited by superfusion of the cells in K⁺‐free solution, the [Na⁺]_i is expected to increase. After 2 min the superfusate was switched to NT containing 6 mm K⁺ to reactivate the Na⁺,K⁺‐ATPase. Reactivation extrudes the accumulated Na⁺ from the cell and this rate of extrusion was used to assess the function of the Na⁺,K⁺‐ATPase. B, pump current measured in myocytes isolated from hearts at 150 days post‐AC (150AC) had reduced Na⁺ extrusion rates compared with the sham group. There was no change in Na⁺ extrusion rates in the age‐matched sham myocytes so these data were combined. One‐way ANOVA with a Sidak post hoc test ^** P < 0.01; n = 18, 15 and 7 for sham, 60AC and 150AC, respectively from 4–8 hearts. Scatter plots show mean (95% CI).