Acetylcholine receptors in extrajunctional regions of innervated muscle have a slow degradation rate.
Scanning EM autoradiography was used to determine the degradation rate of extrajunctional ACh receptors (AChRs) in innervated sternomastoid muscles of the mouse. We report that in innervated muscles, extrajunctional AChRs have a slow degradation rate (t1/2, approximately 8 d), similar to that seen at the neuromuscular junction. We conclude that slowly degrading AChRs (Rs) need not be localized at the specialized structure of the nerve-muscle junction. Degradation of extrajunctional as well as junctional AChRs may depend primarily on the state of innervation of the muscle.
Salpeter
M M
MM
Department of Neurobiology and Behavior, Cornell University, Ithaca, New York 14853.
Marchaterre
M
M
D000818:Animals; D001345:Autoradiography; D006207:Half-Life; D007700:Kinetics; D051379:Mice; D008855:Microscopy, Electron, Scanning; D009132:Muscles / Q000294:innervation*; D009469:Neuromuscular Junction / Q000378:metabolism; D011950:Receptors, Cholinergic / Q000378:metabolism*
D011950:Receptors, Cholinergic