[THE INDICATORS OF GROWTH AND MYOGENESIS IN THE GLYCOLYTIC AND OXIDATIVE MUSCLES OF THE RAT AFTER INDIRECT...

A comparative analysis of the signaling pathways activity and gene expression in the red (RG) and white (WG) parts of the gastrocnemius muscle of rat after a series of short (1 s) tetanic contractions induced by motor nerve stimulation at a frequency of 100 Hz and with an amplitude that provides activation of all motor units of the muscle. WG compared to RG demonstrated a marked increase in the phosphorylation level of ERK1/2, although the increase in the phosphorylation of AMPK was not different in two muscles 2 h after the stimulation. Along with that, content of MyoD and myogenin mRNA in WG increased much higher than in RG, whereas the effect of stimulation on IGF-1, MaFbx and MuRF genes expression was weak and comparable in WG and RG. There was an increase of myostatin mRNA in RG. Thus, glycolytic muscle fibers of WG exhibit more pronounced regulatory shifts of hypertrophic character than oxidative muscle fibers of RG.