Effects of Activities on Expression of Nicotinic Acetylcholine Receptor on Neuromuscular Junction of Skeletal Muscles in Growth Stage

Objective:To describe the development process of skeletal neuromuscular junction(NMJ) in growth stage as well as the effects of activities in this process through the analysis of N acetylcholine receptor(nAChR) subunits expressions.Methods:3-week-old male SD rats have undergone activity increasing(treadmill training,group T) and activity decreasing(tail suspension,group H) intervention respectively.The expressions of γ-,ε-,δ-nAchR mRNA were detected during 3⁸ weeks after birth.Results:1) γ-,ε-,δ-nAChR expressions in rat gastrocnemius decreased rapidly in 3⁵ weeks after birth and only presented trace amounts of expression at 5-week-old stage;2) the expression of γ-nAChR was higher in group H at 5-week-old stage and lower in group T at 8-week-old stage compared with control group.There were no significant differences of ε-and δ-nAChR expressions between groups.Conclusion:The development of NMJ in postnatal stage has a typical sensitive period;exercise training can promote the recession of embryonic γ-nAChR,restriction on movements can significantly delay this process instead.The NMJ has certain structural stability after getting mature.