Figure 7.

Ablation of β2-ARs both delays and attenuates the progression of heart failure after transverse aortic constriction. (A) WT mice showed a significant decrease in cardiac function 1 week after TAC with further deterioration at 2 and 4 weeks. In contrast, β2−/− showed preserved function until 4 weeks after TAC and at that time point, cardiac function is significantly higher in β2−/− compared to WT. n=10 mice, *p<0.05 vs WT. (B) Sarcomeric shortening, (C) velocity of contraction, and (D) relaxation were all decreased in WT after TAC (n=4, *p<0.05 vs sham). However, in β2−/−, % shortening was preserved and the decrease in velocity of contraction was significantly less than WT (#p<0.05 vs. WT). (E) Peak Ca²⁺ and (F) rate of Ca²⁺ release were decreased in WT after TAC compared to sham but not in β2−/−, n=4 mice, *p<0.05 vs WT.