Parvalbumin expression is downregulated in rat fast-twitch skeletal muscles during aging

In this study, the protein expression profile of extensor digitorum longous (EDL) and Soleus (SOL) muscles, representing fast- and slow-twitch skeleta l muscles, respectively, was established using high resolution two-dimensio nal electrophoresis (2-DE). One protein spot was found uniquely expressed i n EDL muscle. N-terminal sequence analysis identified the protein as parval bumin. Parvalbumin is a high affinity calcium binding protein that regulate s muscle contraction and relaxation. Our experiments revealed that parvalbu min expression in EDL muscle was down-regulated during aging. In addition, high-intensity exercise could reverse this age-related change. Soleus muscl es do not normally express parvalbumin, but high-intensity exercise could e ctopically induce its expression in both young and old SOL muscles. We have also confirmed our 2-DE findings by immunohistochemistry on muscle section s. Our results suggest that high-intensity training could be used to improv e muscle functions during aging because parvalbumin play an important role in regulating skeletal muscle contraction and relaxation. (C) 2001 Academic Press.