Effects of aging and physical training on the neuromuscular junction of the mouse.
The effects of age and physical exercise on synaptic function were studied in the neuromuscular junctions of three skeletal muscles of C57BL/6J mice subjected to a regimen of 10 weeks of physical training (30 min/day, 3.5 m/min). Synaptic function was found to be considerably reduced in old age, as revealed by the activity of the cholinergic enzymes choline acetyltransferase (CAT) and acetylcholinesterase (AChE). However, the number of acetylcholine receptors, as judged by specific bungarotoxin binding, was found to be unchanged with either age or exercise. The regimen of training employed did not further reduce CAT and AChE activities beyond the age-dependent changes observed. It is quite possible though that the age-associated decrement in enzyme activities can account for the reduced adaptability of the muscle to exercise in old age.
D000110:Acetylcholinesterase / Q000378:metabolism; D000375:Aging / Q000378:metabolism*; D000818:Animals; D002038:Bungarotoxins / Q000378:metabolism; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D005260:Female; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D009469:Neuromuscular Junction / Q000201:enzymology* / Q000378:metabolism; D010805:Physical Conditioning, Animal; D011950:Receptors, Cholinergic / Q000378:metabolism; D013569:Synapses / Q000201:enzymology / Q000378:metabolism
D002038:Bungarotoxins; D011950:Receptors, Cholinergic; D005954:Glucosephosphate Dehydrogenase; D002795:Choline O-Acetyltransferase; D000110:Acetylcholinesterase