Two populations of mitochondria were observed upon ultrastructural examination of cardiac
muscle tissue, one located directly beneath the sarcolemma (subsarcolemmal mitochondria)
and another between the myofibrils (interfibrillar mitochondria). Subsarcolemmal
mitochondria were released by treatment of heart muscle with a Polytron tissue processor,
while interfibrillar mitochondria were released by nagarse digestion of the remaining tissue.
These results were supported by electron microscopy of Polytron-treated heart tissue …