FIGURE 5.

Activation of wild type and mutant β₂ARs induces distinct responses in contraction rates in cardiac myocytes. A, the β₁β₂AR-KO cardiac myocytes expressing β₂AR, PKAmut β₂AR, or GRKmut β₂AR were stimulated with 10 μm Iso for contraction rate measurement. The base-line levels of contraction rates (B) and the maximal increases in contraction rate after stimulation (C) were plotted. ***, p < 0.001 when compared with the wild type β₂AR by two-way ANOVA. *, p < 0.05 by Student's t test.