Exercise selectively increases G4 AChe activity in fast-twitch muscle.
Acetylcholinesterase (AChe) molecular forms were studied in hindlimb skeletal muscles from adult male Fischer 344 rats subjected to treadmill exercise for periods ranging between 1 and 30 days. Groups of three animals were exercised for 1 h/day at a treadmill speed of 8.5 m/min, with 1-min sprints at 15 m/min every 10 min. This exercise protocol led to a significant increase in the activity of G4 AChe in fast-twitch (gracilis and tibialis) but not in slow-twitch (soleus) muscles. Other AChe forms and muscle protein content remained unaltered. Such a selective enzymatic change was detected after a single exercise session, became more apparent after three daily sessions, and persisted for at least 30 days of exercise. A larger increment in G4 AChe activity was observed in gracilis muscle end-plate vs. non-end-plate regions. These findings show a specific adaptive reaction of fast-twitch muscles to enhanced motor activity, suggest that individual AChe forms in motor end plates are regulated through separate mechanisms, and support the hypothesis that membrane-bound G4 AChe plays an essential role in neuro-muscular transmission.
Fernandez
H L
HL
Neuroscience Research laboratory, Veterans Administration Medical Center, Kansas City, Missouri 64128.
Donoso
J A
JA
D000110:Acetylcholinesterase / Q000378:metabolism*; D000818:Animals; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction; D009132:Muscles / Q000201:enzymology*; D005082:Physical Exertion; D011487:Protein Conformation; D051381:Rats; D011916:Rats, Inbred F344
D000110:Acetylcholinesterase