Figure 7. β-AR blockers suppressed overactivation of Calmodulin Kinase II in rat failing hearts.
(A) Metoprolol alleviated ER stress and overactivation of CaMKII induced by tunicamycin (TM). Cells were pretreated with KN93 (KN, 0.5 µmol/L or 2 µmol/L), metoprolol (M, 10 µmol/L or 20 µmol/L) for 1 hour, and exposed to TM (5 µg/ml) for 24 hours. Cell lysates were then immunoblotted for phosphorylated CaMKII, phosphorylated PERK, GRP78 and CHOP, which were all normalized to β-actin. *P<0.05 vs. control, #P<0.05 vs. TM. (B) Metoprolol suppressed the overactivation of CaMKII in AAC rats. *P<0.05 vs. sham, #P<0.05 vs. AAC.