Neuritic guidance by polyornithine-attached materials of ganglionic origin☆

Developmental Biology

Ruben Adler¹  Silvio Varon¹ 

[1] Department of Biology, School of Medicine, University of California, San Diego, La Jolla, California 92093 USA

关键词: CG;    ciliary ganglion;    CNTF;    ciliary neuronotrophic factor;    EE;    embryo extract;    HCM;    heart-conditioned medium;    HEBM;    modified Eagle's basal medium;    NPF;    neurite-promoting factor;    CG-NPF;    ciliary ganglion-derived NPF;    CM-NPF;    conditioned medium-derived NPF;    PAM;    polyornithine-attached material;    PORN;    polyornithine;   

DOI  :  10.1016/0012-1606(81)90342-0

学科分类：生物科学（综合）

来源: Academic Press

【 摘 要 】

Dissociatedciliaryganglionicneuronsdonotsurviveincultureunlesssuppliedwithanappropriatesourceofciliaryneuronotrophicfactors(CNTF).Moreover,previousworkfromthisandotherlaboratorieshasshownthatpolyornithine(PORN)substratapersedonotallowneuriticdevelopmentfromsuchCNTF-supportedneurons.Neuriticformation,however,wouldtakeplaceifthePORNsubstratumiscoatedwithaneurite-promotingfactor(NPF)fromheartconditionedmedium.UndissociatedchickembryociliarygangliaexplantedonPORNsubstratawillalsoproducealavishradialneuriticoutgrowthonlyiftheyareCNTFsupportedandthesubstratumiscoatedwithNPF.IntheabsenceofexogenousNPFneuritesgrowradiallybutonlytoalimitedextent.Atadistanceofapproximately120μmfromtheexplant,neuritesswitchfromaradialtoacircularortangentialgrowthpattern,thusgivingrisetoaneuriticringalmostconcentricwithrespecttotheexplant.Time-lapsestudiesshowthattheneuriticringisgeneratedthroughacombinationofseveralbehaviorsthatneuritesdisplayuponreachingtheradial-to-circular“transitionzone,”includingbranchingandturningeitherclock-orcounterclockwise.Contributionsarealsomadebyinterneuriticbridgesarisingfromfusionoftangentialfilopodiafromadjacentgrowthcones.Theoverallbehaviorofneuriticoutgrowthsuggeststhattheexplantedciliarygangliaareabletoproducematerialsendowedwithneurite-promotingproperties,whichcoatthePORNsubstratumintheimmediatevicinityoftheganglia.Autoradiographicexperimentsusinggangliaprelabeledwitheither[3H]glucosamineor[14C]leucinedemonstratedtheexistenceofthesematerials.AperiganglionicterritoryofPORN-attachedmaterials(PAMs)ofganglionicorigincanberecognizedafewhoursafterexplantation,beforetheonsetofneuriticemergencefromtheganglion.ThisPAMterritorygrosslycorrespondstotheareathatafewhourslaterwillbeoccupiedbytheneuriticring.IftwogangliaareexplantedatadistanceapproximatelyequaltotwicethedistancenormallycoveredbyadenseperiganglionicPAMhalo,acontinuitybetweenthePAMterritoriesofbothgangliaisestablishedbeforetheonsetofneuriticoutgrowth.Thisoverlappinggeneratesan“avenueofpreferentialterrain”thatprovidesguidancetoneuritesbetweentheneighboringganglia.Thepossibilityisconsideredthatasimilarmechanismofneuriticguidancecouldalsooccurinvivo.

【 授权许可】

Unknown