Activity-independent modulation of acetylcholine receptor levels in rat skeletal muscle following neonatal denervation.
Following denervation of adult muscle, levels of acetylcholine receptor (AChR) increase; normal, low levels are restored only after muscle reinnervation. After neonatal denervation, we found a large initial increase in AChR levels during the first days postsurgery, as in adult denervated muscle. However, 1 week after denervation, total AChR levels decreased in the absence of any sign of reinnervation. By 3 weeks after surgery, near-normal levels of AChR were restored and extrajunctional AChR had disappeared. Thus, in sharp contrast to adult muscle, in young denervated muscle a down-regulation of AChR occurs without recovery of innervation and normal muscle contractile activity. These results suggest that different mechanisms regulate the levels of AChR in developing and adult skeletal muscle.
Blondet
B
B
INSERM U. 153-CNRS URA 614, Développement, Pathologie, Régénération du Système Neuromusculaire, Paris, France.
Rieger
F
F
Verdière-Sahugué
M
M
D000110:Acetylcholinesterase / Q000378:metabolism; D000818:Animals; D002038:Bungarotoxins / Q000378:metabolism; D009121:Muscle Denervation; D009132:Muscles / Q000294:innervation / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011950:Receptors, Cholinergic / Q000378:metabolism*; D013997:Time Factors
D002038:Bungarotoxins; D011950:Receptors, Cholinergic; D000110:Acetylcholinesterase