Acetylcholine receptor organization at the dystrophic extraocular muscle neuromuscular junction.
Spared extraocular muscles of dystrophic mice are not subjected to regeneration process and can be used to verify whether the lack of dystrophin per se could cause changes in acetylcholine receptor (AChR) distribution. In the present study, rectus and oblique (spared) and retractor bulbi (nonspared) muscles were dissected from adult control (C57Bl/10) and mdx mice. AChRs and nerve terminals were labeled with rhodamine-alpha-bungarotoxin and anti-NF200-IgG-FITC, respectively, and visualized by confocal microscopy. Rectus and oblique muscles presented 0.5% central nucleation, while retractor bulbi had central nucleation in 45% of muscle fibers. In mdx rectus, AChRs were distributed in branches in 99% of the junctions examined (n = 200), similar to that observed for controls. Nerve terminals covered the AChR branches in 100% of the junctions examined. In control retractor bulbi, AChRs were distributed in regular branches. In mdx retractor bulbi, multiple fragmented islands of receptors were seen in 56% of the endplates examined (n = 200). These results suggest that the lack of dystrophin per se does not influence the distribution of acetylcholine receptors at the neuromuscular junction of spared extraocular muscles.
Marques
Maria Julia
MJ
Departamento de Anatomia, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, São Paulo 13083-970, Brazil. marques@.unicamp.br
Pertille
Adriana
A
Carvalho
Candida Luiza T
CL
Santo Neto
Humberto
H
D000818:Animals; D002038:Bungarotoxins; D004195:Disease Models, Animal; D016189:Dystrophin / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D005456:Fluorescent Dyes; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018101:Mice, Inbred mdx; D018613:Microscopy, Confocal; D018482:Muscle, Skeletal / Q000294:innervation* / Q000378:metabolism / Q000473:pathology; D009137:Muscular Dystrophy, Animal / Q000378:metabolism* / Q000473:pathology; D020388:Muscular Dystrophy, Duchenne / Q000378:metabolism* / Q000473:pathology; D016900:Neurofilament Proteins / Q000378:metabolism; D009469:Neuromuscular Junction / Q000378:metabolism*; D017729:Presynaptic Terminals / Q000378:metabolism*; D011950:Receptors, Cholinergic / Q000378:metabolism*; D012038:Regeneration; D012235:Rhodamines
D002038:Bungarotoxins; D016189:Dystrophin; D005456:Fluorescent Dyes; D016900:Neurofilament Proteins; D011950:Receptors, Cholinergic; D012235:Rhodamines; C494031:rhodamine-alpha-bungarotoxin; C051774:neurofilament protein H