Exercise-induced fibre type transitions with regard to myosin, parvalbumin, and sarcoplasmic reticulum in muscles of the rat.

Effects of a long-term, high intensity training program upon histochemically assessed myofibrillar actomyosin ATPase, myosin composition, peptide pattern of sarcoplasmic reticulum (SR), and parvalbumin content were analysed in muscles from the same rats which were used in a previous study (Green et al. 1983). Following 15 weeks of extreme training, an increase in type I and type II A fibres and a decrease in type II B fibres occurred both in plantaris and extensor digitorum longus (EDL) muscles.

Relationships between early alterations in parvalbumins, sarcoplasmic reticulum and metabolic enzymes in chronically stimulated fast twitch muscle.

The present study compares the time courses of the early changes in parvalbumin content, in the properties of the sarcoplasmic reticulum (SR) and in activity and isozyme patterns of metabolic enzymes in chronically (12 h/day) stimulated fast twitch tibialis anterior (TA) muscle of the rabbit. Under the chosen conditions of stimulation, the first significant changes appeared after 6 days. Except for the delayed reduction in pyruvate kinase, the time course of the changes were the same.

The ratio between intrinsic 115 kDa and 30 kDa peptides as a marker of fibre type-specific sarcoplasmic reticulum in mammalian muscles.

Sarcoplasmic reticulum displays characteristic differences in Ca2+-uptake, Ca2+-ATPase and the pattern of membrane proteins in type I, IIA and IIB fibres. The ratio between the 115 kDa Ca2+-ATPase and a 30 kDa protein is of characteristic magnitude in the sarcoplasmic reticulum of the three fibre types in rat muscles. The slow-to-fast fibre type transformation observed in rabbits during chronic nerve stimulation is accompanied by predictable changes of this ratio.

Electrophoretic analyses of myofibrillar proteins from the body wall muscles of Ascaris suum.

A myofibrillar protein extract has been isolated from the muscle of Ascaris suum. Two-dimensional electrophoresis of this extract revealed that the myosin light chain 1 (ALC1) migrates as 3 components with approximate isoelectric points in the range of 5.3-5.