Morphological peculiarities of neuromuscular junctions among different fiber types: Effect of exercise


Submitted: 15 March 2017
Accepted: 30 May 2017
Published: 27 June 2017
Abstract Views: 1340
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Authors

  • Teet Seene Institute of Exercise Biology and Physiotherapy, University of Tartu, Estonia.
  • Maria Umnova Institute of Exercise Biology and Physiotherapy, University of Tartu, Estonia.
  • Priit Kaasik Institute of Exercise Biology and Physiotherapy, University of Tartu, Estonia.
The aim of our research was to examine whether there are differences in the morphology of neuromuscular junctions of different types of muscle fibers in rodents, and after their adaptation to six weeks endurance exercise training. After 5-day acclimation, Wistar rats were subjected to run with the speed 35 m/min during 6 week, 5 days per week and the training volume reached 60 min per day. Muscle samples for ultrastructural studies were fixed, dehydrated and embedded in Epon-812. Ultra-thin sections were cut from longitudinally and transversely oriented blocs, using 4 blocks from each animal. The area of axon terminals on fast- twitch fibers is 1.5 time large (p<0.001) and the perimeter of terminals is 1.7 time large in comparison with slow- twitch oxidative fibers (p<0.001) in control group. There are correlation between cross-sectional area of different muscle fibers and length of axon terminals (r=0.72), between cross-sectional area and with of axon terminal (r=-0.62), and between turnover rate of contractile proteins and length of axon terminal (r=0.75). Fast remodeling of synapse on oxidative and oxidative-glycolytic muscle fibers during endurance training seems to guarantees the intensive renewal of the structures of muscle fibers with higher oxidative capacity.

Teet Seene, Institute of Exercise Biology and Physiotherapy, University of Tartu
Institute of Sport Sciences and Physiotherapy

Supporting Agencies

the Estoninan Research Council, research project number TMVSF14058I

Seene, T., Umnova, M., & Kaasik, P. (2017). Morphological peculiarities of neuromuscular junctions among different fiber types: Effect of exercise. European Journal of Translational Myology, 27(3). https://doi.org/10.4081/ejtm.2017.6708

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