Skeletal muscle fibre types: detection methods and embryonic determinants

M. Zhang, K. Koishi and I.S. McLennan

Department of Anatomy and Structural Biology, University of Otago, Dunedin, New Zealand

Offprint requests to: Dr. Ian S. McLennan, Department of Anatomy and Structural Biology, University of Otago, PO Box 913, Dunedin, New Zealand

Summary. Muscle fibres used to be simply classified as either type I, IIa or IIb. Advances in molecular and histological techniques have, however, lead to the realisation that the phenotypes of muscles are more varied than this. An additional fibre type (IIX/IID) has been discovered, fibres with intermediate fibre types have been described and there is accumulating evidence that the fibres types described from the study of limb muscles are not necessarily applicable to other skeletal muscles, such as the jaw and extra-ocular muscles. Further to this has been the discovery that diversity occurs at all stages of muscle development. There are subpopulations of myoblasts and myotubes as well as various types of muscle fibres. The relationships between the different stages of development is still under study. However, it is clear that each stage of muscle development is influenced to a certain degree by prior events. Consequently, the characteristics of mature fibres reflect both their developmental origins and influences from the adult environment, such as their patterns of muscle activation. Histol Histopathol 13, 201-207 (1998)

Key words: Myoblast, Myosin heavy chain, Myotube, Immunohistochemistry

DOI: 10.14670/HH-13.201