DISTRIBUTION AND RELATIVE SIZES OF FIBER TYPES IN EXTENSOR DIGITORUM LONGUS AND SOLEUS MUSCLES OF ADULT RAT

  • 1 January 1977
    • journal article
    • research article
    • Vol. 123  (APR) , 467-486
Abstract
Histochemical fiber types classified in sections stained for succinic dehydrogenase (SDH) and myosin ATPase (pH 9.4) were distributed in a consistent manner within the extensor digitorum longus and soleus muscles of the adult rat. Simple morphometric methods based on total fiber counts and applied to complete transverse sections of both muscles showed that relative distributions and proportions along their deep to superificial and medial to lateral axes varied according to the particular histochemical method used for fiber typing. The discrepancies between distributions particularly concerned the Type 2A and Type 1 fiber populations. Similar differences occurred when the relative ranges of fiber size exhibited by each fiber type were compared in sections stained for SDH and ATPase. The variation in classifications were confirmed by a brief analysis of individual fibers in serial sections stained alternately for these 2 enzymes.