RESUMO
INTRODUCTION: Exercise training induces significant changes in the performance of skeletal muscle. PURPOSE: To determine whether changes in the gene expression of rat hind-limb muscle sarcoplasmic reticulum Ca2+ -ATPase isoforms (SERCA1a and SERCA2a) in response to either moderate- or high-intensity exercise training underlie the functional remodeling. METHODS: SERCA1a and SERCA2a isoform mRNA expression was determined in predominantly fast-twitch, gastrocnemius muscle and predominantly slow-twitch, soleus muscle with northern analysis. SERCA mRNA was normalized by the 18S rRNA measured in the same sample. RESULTS: Significant increases in the gastrocnemius SERCA2a mRNA expression were observed after both moderate- and high-intensity training. No significant change in SERCA1a expression was found under any conditions. CONCLUSION: These results indicate that both moderate and high intensity exercise increase the relative SERCA2a expression in the gastrocnemius.
