Quantitative histochemistry of three mouse hind-limb muscles: the relationship between calcium-stimulated myofibrillar ATPase and succinate dehydrogenase activities.

A quantitative modification of Meijer 's calcium-lead capture method, for the demonstration of calcium-stimulated myofibrillar ATPase activity at physiological pH, is described. A range of myofibrillar ATPase activities has been found among fast muscle fibres in two mouse hind-limb muscles. The myofibrillar ATPase activity of fast muscle fibres is 1.5-3 times higher than the myofibrillar ATPase activity of slow muscle fibres. Myofibrillar ATPase activities and succinate dehydrogenase activities of individual muscle fibres have been determined in serial sections. Activities of the two enzymes are correlated positively in soleus (fast and slow fibres), and negatively in plantaris (almost all fast) and extensor digitorum longus muscle (all fast). However, this correlation is not significant among the oxidative fibres in the extensor digitorum longus. The fibres of the latter muscle cannot be classified satisfactorily into two sub-types.