The Location of Muscle Calcium with Respect to the Myofibrils

Abstract

Autoradiographs have been prepared from frog toe muscles soaked in Ca45 and fixed with an osmium-oxalate solution. A majority of the grains over the A-bands were over the myofibrils. The grain density over the I-bands was greatest over the space between the myofibrils. The significance of this distribution is discussed in the light of previous information about the longitudinal distribution of Ca45 in skeletal muscle.