Glycogen in Crustacean Fast and Slow Muscles

Abstract

SYNOPSIS. Ultrastructural examination of crayfish superficial (tonic) and deep (phasic) abdominal extensor muscles reveals a distribution and quantitative difference in glycogen between these muscles. Both superficial and deep fibers have a dense accumulation of glycogen in the interfibrillar sarcoplasm. In addition, the superficial extensors, but not the deep extensors, contain glycogen in the I band region. The glycogen granules are of the j3 type and can be removed enzymatically. The superficial medial and lateral fibers contain more glycogen than the medial and lateral deep fibers. A possible functional role for this difference is suggested.