Competition at silent synapses in reinnervated skeletal muscle.
Synaptic connections are made and broken in an activity-dependent manner in diverse regions of the nervous system. However, whether activity is strictly necessary for synapse elimination has not been resolved directly. Here we report that synaptic terminals occupying motor endplates made electrically silent by tetrodotoxin and alpha-bungarotoxin block were frequently displaced by regenerating axons that were also both inactive and synaptically ineffective. Thus, neither evoked nor spontaneous activation of acetylcholine receptors is required for competitive reoccupation of neuromuscular synaptic sites by regenerating motor axons.
Costanzo
E M
EM
Department of Neuroscience, University of Edinburgh Medical School, Edinburgh EH8 9LE, UK.
Barry
J A
JA
Ribchester
R R
RR
D000818:Animals; D001369:Axons / Q000187:drug effects / Q000502:physiology; D002038:Bungarotoxins / Q000494:pharmacology; D005260:Female; D009045:Motor Endplate / Q000187:drug effects / Q000502:physiology*; D009121:Muscle Denervation; D018485:Muscle Fibers, Skeletal / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation*; D009409:Nerve Crush; D009416:Nerve Regeneration; D017729:Presynaptic Terminals / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013569:Synapses / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology
D002038:Bungarotoxins; D013779:Tetrodotoxin