Molecular adaptations of voltage-gated sodium ion channel related proteins after fatiguing stretch-shortening cycle exercise.
Dystrophin associated protein alpha-syntrophin is known to interact with voltage-gated sodium ion channel (NaCh). Dystrophin is known to be sensitive to eccentric muscle actions. For this reason, the function of the NaChs might also be affected. Molecular adaptations of dystrophin, alpha-syntrophin and NaChs were investigated after fatiguing stretch-shortening cycle (SSC) exercise, which consisted of unilateral jumps on a sledge apparatus. Muscle biopsies were taken from the vastus lateralis muscle of eight healthy subjects immediately after (IA) and 2 days after (2D) the exercise to analyze mRNA levels and immunohistochemical staining patterns. SSC exercise resulted in decreased isometric maximal voluntary contraction (IA: -31+/-9%, 2D: -14+/-16%) and a delayed increase of plasma creatine kinase activity (2D: +178+/-211%). Despite muscle soreness (P<0.001), no morphological damage was observed and no changes were found in the mRNA concentrations. However, the relative changes of the mRNA concentrations of alpha-syntrophin and NaChs were highly correlated (r=0.93, P<0.001) 2D after SSC exercise. This consistent pattern of mRNA regulation may imply a functional relationship between these two proteins. In addition, the current experiment emphasises high inter-individual variation in molecular responses to heavy exercise.
Piitulainen
H
H
Department of Biology of Physical Activity, Neuromuscular Research Center, University of Jyväskylä, Jyväskylä, Finland. harri.piitulainen@sport.jyu.fi
Kivelä
R
R
Komi
P
P
Kainulainen
H
H
Kyröläinen
H
H
D000222:Adaptation, Physiological; D000328:Adult; D002135:Calcium-Binding Proteins / Q000378:metabolism; D003404:Creatinine / Q000097:blood; D016189:Dystrophin / Q000378:metabolism; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D018763:Muscle Fatigue / Q000502:physiology*; D009124:Muscle Proteins / Q000378:metabolism; D053580:Muscle Strength / Q000502:physiology*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis / Q000502:physiology; D015222:Sodium Channels / Q000378:metabolism / Q000502:physiology*; D055815:Young Adult
D002135:Calcium-Binding Proteins; D016189:Dystrophin; D008565:Membrane Proteins; D009124:Muscle Proteins; D012333:RNA, Messenger; D015222:Sodium Channels; C091825:syntrophin alpha1; D003404:Creatinine