Response of the Neuromuscular Unit to Spaceflight: What Has Been Learned from the Rat Model

  title={Response of the Neuromuscular Unit to Spaceflight: What Has Been Learned from the Rat Model},
  author={Roland R. Roy and Kenneth M. Baldwin and V. Reggie Edgerton},
  journal={Exercise and Sport Sciences Reviews},
Despite the inherent limitations placed on spaceflight investigations, much has been learned about the adaptations of the neuromuscular system to weightlessness from studies of rats flown for relatively short periods (approximately 4-22 days). Below is a summary of the major effects of spaceflight observed in muscles of rats that are not in their rapid growth stage: 1. Skeletal muscles atrophy rapidly during spaceflight; significant atrophy is observed as early as after 4 days of flight. 2. The… 

Survey of studies on how spaceflight affects rodent skeletal muscle.

Recovery of neuromuscular junction morphology following 16 days of spaceflight

The results suggest that the neuromuscular system possesses a robust capacity to recover from spaceflight‐induced perturbations upon return to normal gravitational influences.

Neuromuscular adaptations to spaceflight are specific to postural muscles

The findings suggest that the deleterious effects of microgravity are most apparent among postural muscles, and are manifested both in myofibers and their synapses.

Effects of spaceflight on murine skeletal muscle gene expression.

It is demonstrated that spaceflight induces significant changes in mRNA expression of genes associated with muscle growth and fiber type, as well as a significant decrease in levels of the microRNA miR-206.

Effects of spaceflight on rhesus quadrupedal locomotion after return to 1G.

Adaptations in tendon force and EMG amplitude ratios indicate that the nervous system undergoes a reorganization of the recruitment patterns biased toward an increased recruitment of fast versus slow motor units and flexor versus extensor muscles.

Comparison of soleus muscles from rats exposed to microgravity for 10 versus 14 days

Comparing the effects of two different duration spaceflights on the extent of atrophy, fiber type composition, and myosin heavy chain (MHC) content of rat soleus muscles were compared suggested fast-to-faster transformations continued during the longer spaceflight.

Comparison of knee motion on Earth and in space: an observational study

Overall knee-joint motion is reduced, and there is a transformation in the type of muscle action compared to that seen on Earth, with more isometric action at the expense of concentric and particularly eccentric action.

Space travel directly induces skeletal muscle atrophy

Results show for the first time that skeletal muscle fibers are directly responsive to space travel and should be a target for countermeasure development.