Fig. 5.

Carvedilol-mediated enhanced skeletal muscle tetanic force requires β-arrestin 1. The absolute forces at 160 Hz (A) and at 300 Hz (B) of EDL muscles from βarr1Flox and βarr1smKO mice were examined after 2 wk of carvedilol (1 mg/kg/day), metoprolol (10 mg/kg/day), and clenbuterol (1 mg/kg/day) in the vehicle (10% DMSO, 300 mM ascorbic acid in saline solution). Data represent the mean ± SEM for n independent EDL muscles as marked in the figure. Statistical comparison was performed by using a one-way ANOVA with Tukey’s multiple comparison test (vs. vehicle treatment).