Alterations in contractility and intracellular Ca2+ transients in isolated bundles of skeletal muscle fibers from rats with chronic heart failure

Abstract

To determine if chronic heart failure (CHF) leads to functional or structural alterations of skeletal muscle, we compared intracellular Ca2+ signaling, contractility, and the rate of fatigue development, together with electron microscopy (EM), in skeletal muscle preparations from rats with myocardial infarction-induced CHF versus sham-operated control rats. Bundles of 100 to 200 cells were dissected from the extensor digitorum longus (EDL) muscle of control (n=13) and CHF (n=19) rats and were either loaded with aequorin or fixed for EM. Muscles from CHF rats exhibited depressed tension development compared with control muscles during twitches (1.4±0.2 versus 2.8±0.7 g/mm2, P