Postnatal maturation of nerve-muscle junctions in hindlimb muscles of the mouse
[摘要] Themorphologicalmaturationofnerve-musclejunctionsinhindlimbmusclesofthemousewasstudiedduringthefirstmonthafterbirth.Atbirththeadultpopulationofmusclefibersandmotoraxonsisnearlycompleteandthelatterareabouttobecomemyelinatedintheirextramuscularregion.Eachneonatalmusclefiberisinnervatedwithinawell-definedjunctionalzonebynumerousfineprocessesofseveralmotoraxons.Thiszoneisoccupiedroughlyuniformlybyahighdensityofacetylcholinereceptors(AChR,labeledwithafluorescentconjugateofα-bungarotoxin).Polyneuronalinnervationofindividualmusclefibersislostduringthesecondweekafterbirth.Followingtheeliminationofredundantsynapticcontactsthesurvivingpreterminalaxonsgrowandbecomemyelinatedandtheirterminalsexpandwithinthejunctionalzonewhichbeginstogrowmorerapidly.ThedistributionofAChRchangesmarkedlyduringthethirdweekafterbirth.SpotsoflowAChRdensityappearwhichenlargetoformthenonsynapticregionsofthematurejunctionalzoneasthereceptorsbecomecloselyassociatedwiththematuringbranchesofthemotoraxonterminals.Thesubsequentincreaseinareaofthejunctionalzonecloselyparallelsthatofthemusclefiberasawhole.
[发布日期] [发布机构]
[效力级别] [学科分类] 生物科学（综合）
[关键词] [时效性]
