Figure 1.

Mice lacking Kvβ2 exhibit reduced baseline exercise capacity. (A,B) Summary plots showing body weight at baseline (pre-training; A) and lean and fat mass body compositions (B) measured in wild-type (wt) and β2^−/− mice. (A) p = 0.10, unpaired t-test, n = 20 mice each; (B) ns: p > 0.05, Kruskal-Wallis test with Dunn's multiple comparisons test. (C) Total activity (sum of beam break counts over 10 min intervals for 24 h) during light and dark phases, as indicated, measured in wt and β2^−/− mice; ns: p > 0.05, one-way ANOVA with Šídák's multiple comparisons test. (D) Summary plot showing mean respiratory exchange ratios (VCO₂:VO₂) measured in wt and β2^−/− mice during light and dark phases. ns: p > 0.05, Brown-Forsythe ANOVA test with Dunnett's multiple comparisons test; n = 8 mice each. (E) Schematic (top) showing exercise capacity test protocol in which mice are subjected to increasing grade and speed on a treadmill to exhaustion (see Methods); and, horizontal plot showing time of exhaustion for wt and β2^−/− mice. *p < 0.05, unpaired t-test, n = 19–20 mice. (F) Blood lactate concentration measured before capacity test (baseline) and immediately upon fatigue in wt and β2^−/− mice. **p < 0.01, ns: p > 0.05, two-way ANOVA with Šídák's multiple comparisons test, n = 12–16 mice. (G) Summary of distance (top) and work performed (bottom) at exhaustion in wt and β2^−/− mice. *p < 0.05; n = 15–20 mice.