text: Yo, we peeped the changes in neurotrophin-3 (NT-3)
  And its tyrosine kinase C (TrkC) receptor, you see?
  In the neuromuscular system, we got it all mapped
  From voluntary physical activity, that's a fact
  
  We checked the mRNAs and proteins real tight
  NT-3 and TrkC, in the spinal cord's light
  After 3 and 7 days of wheel running, we saw
  Quantitative Taqman RT-PCR, no flaw
  
  mRNA measured, protein levels assessed
  NT-3 in the spinal cord, it progressed
  7 days of exercise, it increased in a spree
  Statistical significance, yeah, that's the key
  
  Immunohistochemical analyses revealed the game
  NT-3 was poppin' in the substantia gelatinosa, no shame
  And the dorsal horn's nucleus, it was there too
  NT-3 was makin' moves, that's what it do
  
  TrkC mRNA levels, they were on the rise
  In the spinal cord, after 3 and 7 days' tries
  In the soleus muscle, things were gettin' real
  NT-3 mRNA levels went up, that's the deal
  
  TrkC receptor, it joined the party as well
  After 3 days of running, you could really tell
  But NT-3 protein levels, they stayed the same
  No effect on them, they played no game
  
  So there you have it, voluntary exercise in the mix
  Differential effects, ain't that a fix?
  NT-3 and TrkC, neural and muscular components
  Voluntary activity's role, that's the main event