Figure 5. Electric pulse stimulation of C2C12 myotubes alters the myosin heavy chain expression patterns.

A, C2C12 myotubes were EPS-stimulated for 24 consecutive hours. Three hours after stimulation, cells were harvested, RNA prepared and relative gene expression quantified by real-time PCR. The transcript levels were compared to unstimulated control cells. B, Mice were trained for 6 weeks. The animals were sacrificed 3 days after the last exercise bout, RNA isolated from gastrocnemius and relative gene expression determined by real-time PCR. Transcriptional induction was compared to the gene expression in sedentary control mice. C, Mice underwent one endurance trial and sacrificed 4 h later. RNA was isolated, relative gene expression quantified by real-time PCR and compared to that of sedentary control mice. Bars are average levels and error bars depict standard deviations. The data of the C2C12 study are from three independent experiments. In the animal studies, n = 8 animals per group were used except for the chronic exercise cohort with n = 7. *p<0.05. Abbreviations: MyHCI, myosin heavy chain I; MyHCIIa, myosin heavy chain IIa; MyHCIIx, myosin heavy chain IIx; MyHCIIb, myosin heavy chain IIb; EPS, electric pulse stimulation.