Scanning electron microscopy of nerve-muscle contacts in embryonic cell culture☆

[摘要] Scanningelectronmicroscopy(SEM)ofcellculturesofdissociatednerveandmusclefromchickembryoshasshownthatdevelopingmusclefiberscanbecontactedatmanysitesbyoneormorethanoneneuron,andthatasinglenervecansendbranchestoseveralmyofibers.Atthesecontactregionsofnervewithmuscle,theneuronssendoutterminalorlateralsproutswithfinetipswhichinitiallylackterminalswellings,butlateracquiresmall“bouton”-likestructuresincontactwiththesarcolemma,whichresembleembryonicsynapses.Atthesepoints,thesarcolemmadoesnotappeartodifferinultrastructurefromothersurfaceregionsofthemyofiber.Transmissionelectronmicroscopy(TEM)hasrevealedthepresenceofbothelectronlucentanddense-coredvesiclesatsomenerveterminals.However,fluorescencehistochemistry(Falck-Hillarptechnique)failedtodetectthepresenceofcatecholaminesinthesecultures.TheSEMpicturesatsubstantiallyhigherresolutionsthanthelightmicroscope,andtheenhancedthreedimensionalperspectiveofthistechnique,provideadditionalinformationaboutthedevelopmentalmorphologyofthenerve-musclecellculturesystem.Theresultsarecorrelatedwithpreviousfindingsbylightmicroscopy,TEMandelectrophysiology,anddiscussedinrelationshiptoproposedinnervationprocessesofskeletalmusclefibersinvivo.

[学科分类] 生物科学（综合）