北大神经生物学课件2神经元和神经胶质细胞-神经元.ppt

CellularNeurobiology,NeuroscienceResearchInstitutePekingUniversityDepartmentofNeurobiologyPekingUniversityHealthScienceCenter,AlbertCheung-HoiYU于常海,北京大學神經科學研究所,achy,OneoftheCajalsmanydrawingsofBraincircuity,TheletterslabelthedifferentelementsCajalidentifiedinanareaofthehumancerebralcortexthatcontrolsvoluntarymovement.,Neurons:Excitablecells“wiring”“SignalSenders”Neuroglia:Support,Nurturing,Insulation,CellularComponents,NerveCells,Neurons,Neuroglia,Cellbody(soma;perikaryon)Axon:onlyone(branchesarecollaterals;terminalsareendfeet)Dendrites:muchshorter;oneormorethanone;branchextensivelyintodendritictrees,StructureofNeurons,AxonHillock,(Axonalendfeet),TheAxonandAxonCollaterals,CellBody(Soma):LifeSupportProteinSynthesisSingleNucleus,RER(NisslBodies)Axon:LongestprocesstransmitsmessagesawayfromcellbodyDendrites:Multipleprocessesoffcellbodyreceivemessages,NeuronsStructurereceivestimuliandtransmitafferentimpulsestoCNSInterneuronscommunicatingbetweenneurons;formcircuitsintheCNSMotorneuronfromCNStoeffectorcells;deliverefferentimpulsesoutthroughthePNStotheeffectorstocarryouttheactionsdirectedbytheCNS,FunctionalClassificationofNeuron,EXCITABLEMembrane:Abletoregulatethemovementofions(charges)acrossandalongmembraneSIGNALTRANSDUCTIONDONOTReplicate:Damagedcellscannotbereplaced!,ImportantFeaturesofNeurons,ActionPotential,FourFunctionalRegionsofModelNeurons,Impulsetransmission:electricalchemicalMorphology:axodendriticaxonsomaticaxoaxonicdendrodendritic,ClassificationofSynapses,synapse,4,VesiclesreleaseNeurotransmitters,Chemicalsynapse:presynapticknob(presynapticcomponent)synapticvesiclessynapticcleftpostsynapticmembrane(postsynapticcomponent)Electricalsynapse:gapjunctions,SynapseStructures,DistinguishingPropertiesofElectricalandChemicalSynapses,Atachemicalsynapse,neuronstransmitinformationacrossacleft.,SmallMoleculeNeurotransmitterSubstancesAcetylcholine(ACh);Dopamine(DA);Norepinephrine(NE);Serotonin(5-HT);HistamineAminoAcidsGamma-aminobutyricacid(GABA);Glycine;Glutamate;AspartateNeuroactivePeptides-partiallist!Bradykinin;beta-endorphin;calcitonin;cholecystokinin;enkephalin;dynorphin;insulin;gastrin;substanceP;glucagon;secretin;vasopressin;oxytocin,etc.,ListofSomeNeurotransmitters,Axonaltransport:intracellularcommunicationBidirectionalmechanism:anterogradetransportretrogradetransportClassifiedbytransportrates:slowtransportsystem(0.2to1mm/day)fasttransportsystem(200to400mm/day),AxonalTransportSystems,HitchingaRideon“Retrorail”,Membranesoforganellesinvolvedinsynaptictransmissionarereturnedtothecellbodyforreuseordegradation,Nucleus,Cytoskeleton,(Anterogradetransport),MajorRateComponentsofAxonalTransport,1.Neuronshavespecializedprojectionscalleddendritesandaxons.Dendritestakeinformationtothecellbodyandaxonstakeinformationawayfromthecellbody2.Neuronscommunicatewitheachotherthroughanelectrochemicalprocess3.Neuronscontainsomespecializedstructures(likesynapses)andchemicals(likeneurotransmitters)4.NisslBodies5.DONOTReplicate:Damagedcellscannotbereplaced!,NeuronsdifferfromOtherCells,Neuron:Supportingcells:CNS:neuroglia(glia)PNS:SchwanncellsandsatellitecellsFunctions:physicalsupportelectricalinsulationmetabolicexchangeblood-brainbarrier,CompositionofNervousTissue,NeurogliaintheCNS,Abletoreplicate!ImportanceinnervoussystemfunctionisVASTLYunderestimated!Evidenceismounting:NurturingroleSignalingrole(Memory?)InflammationPainManymoretocome!,Neuroglia:DistinguishingFeatures,PresenceoftightjunctionsbetweentheendothelialcellsOneofthenotablefeaturesofendothelialcellsincomparisontoothercellisthelackofpinocyticvesiclesSelectivepermeabilitytomoleculesbasedontheirmolecularweightandlipidsolubilityPresenceofspecificmarkersRichintwoenzymes:gammaglutamyltranspeptidase(GGTP)(foraminoacidtransport)andalkalinephosphatase(transportofphsopahteions)usedasmarkerforBBB.Others:glucosetransporter(GLUT-1);endothelialbarrierantigen(EBA;unknownfunction)andantigenrecognizedbytheMRCOX-47monoclonalantibody(importantforcell-to-celladhesion);transferrinreceptor(transportofferricions).,PropertiesofBloodBrainBarriers,BBB,1.NeuronshaveTWOprocessescalledaxonsanddendrites.GlialcellsonlyhaveONE.2.NeuronsCANgenerateactionpotentials.GlialcellsCANNOT,however,dohavearestingpotential.3.NeuronsHAVEsynapsesthatuseneurotransmitters.GlialcellsdoNOThavechemicalsynapses.4.NeuronsdoNOTcontinuetodivide.GlialcellsDOcontinuetodivide.5.TherearemanyMORE(10-50timesmore)glialcellsinthebraincomparedtothenumberofneurons.,Gliaaredifferentfromneurons:,NerveCells,Neurons,Glia,ExtracellularSpace,andBlood,BidirectionalCommunicationPartnersintheCNS,ReceivingsignalsfromneighboringneuronsandrespondingtothemwithreleaseofneuroactivesubstancesExpressreceptorsforalmostallneurotransmittersandneuromodulatorsIncreaseofintracellularcalciumconcentrationMembranedepolarizationinastrocytesarecommonresponsestoneuralactivityMetabolicallycoupledtoneuralactivity,MetabolismofAstrocytesandtheirMetabolicCooperationwithNeurons,GlucoseAminoacidmetabolismEnzymes:glutaminesynthetase(glutamate-glutaminecycle);glycogenphosphorylatase(glycogenmobilization);pyruvatecarboxylase(anapleroticsynthesisofoxaloacetate);cysteinesulfinatedecarboxylase(synthesisoftaurine