Expression of skeletal muscle sarcoplasmic reticulum calcium-ATPase is reduced in rats with postinfarction heart failure

Objective-To determine whether heart failure in rats is associated with alt ered expression of the skeletal muscle sarcoplasmic reticulum Ca2+-ATPase ( SERCA). Methods-SERCA protein and mRNA were examined in the soleus muscles of eight female rats with heart failure induced by coronary artery ligation, six we eks after the procedure (mean (SEM) left ventricular end diastolic pressure 20.4 (2.2) mm Hg) and in six sham operated controls by western and norther n analyses, respectively. Results-SERCA-2a isoform protein was reduced by 16% (112 000 (4000) v 134 0 00 (2000) arbitrary units, p < 0.001), and SERCA-2a messenger RNA was reduc ed by 59% (0.24 (0.06) v 0.58 (0.02) arbitrary units, p < 0.001). Although rats with heart failure had smaller muscles (0.54 mg/g v 0.66 mg/g body wei ght), no difference in locomotor activity was observed. Conclusions-These results may explain the previously documented abnormaliti es in calcium handling in skeletal muscle from animals with the same model of congestive heart failure, and could be responsible for the accelerated m uscle fatigue characteristic of patients with heart failure.