Figure 4. The imbalance of SERCA2 and NCX1 in TAC mice is blocked by a calmodulin antagonist.

Immunoblotting was carried out using antibodies that recognized SERCA2 or NCX1 in the indicated groups. Top panels: representative immunoblots of SERCA2 (A) and NCX1 (B) in the indicated groups. Bottom panels: densitometric analysis of relative SERCA2 (A) and NCX1 (B) levels. Densitometry values were normalized to the average of all sham values, which corresponded to 100% (mean ± SEM, n = 6). ^* P<0.05, ^** P<0.01 vs. sham-operated mice; ^# P<0.05, ^## P<0.01 vs. TAC-treated mice. (C) Original traces of the current in either sham or TAC adult cardiomyocytes after the application of 10 mmol/L caffeine, either with or without DY-9836 treatment (20 mg/kg) treatment. The arrow indicates the time of caffeine administration. The amplitude of the caffeine-induced Ca²⁺ transient current can be used as an index of SR Ca²⁺ content. (D) Mean amplitudes of Ca²⁺ transients in TAC adult cardiomyocytes after treatment either with or without DY-9836 treatment (20 mg/kg). F/F0; fluorescence intensity/background fluorescence levels; ^** P<0.01 vs. sham cells, ^## P<0.01 vs. TAC cells.