Lipidic mitochondrial inclusions in experimentally-induced in vitro myopathy of mouse diaphragm.

1. Treatment of murine skeletal muscle with the Ca2(+)-channel agonist, Bay K 8644, induces myopathic changes including configurational changes of the mitochondria. 2. During the progression of the myopathy the mitochondria apparently engulf neighboring lipid droplets. 3. Mitochondrial changes are most marked when damage to the muscle is most severe, are prevented under conditions that should reduce Bay K 8644-induced Ca2(+)-influx, and are not modified by various maneuvers designed to prevent the generation of free radical species.