Development of sympathetic neurons in compartmentalized cultures: I. Local control of neurite growth by nerve growth factor

[摘要] Sympatheticneuronsfromthesuperiorcervicalgangliaofnewbornratswereplatedinthecentercompartmentsofthree-compartmentdishesandtheeffectsofthelocalconcentrationof7Snervegrowthfactor(NGF)onneuriteextensionanddensityinthesidecompartmentswereobserved.Omissionofratserumandascorbatefromtheculturemediuminthesidecompartmentsprovedfavorablefortheobservationofneuritegrowththere,whiletheseingredientsweresuppliedtotheneuronsviathecentercompartments.Undertheseconditions,7SNGFconcentrationsranging0.01–10μg/mlproducedlittledifferenceintherateofneuriteextension(about1mm/day).However,asubstantialinfluenceonfiberdensitywasobserved,withhigherdensitiesproducedinsidecompartmentsgiven1–10μgNGF/mlthaninoppositesidecompartmentsofthesameculturesgiven0.1μg/mlorless.Thiswasobservedirrespectiveofwhetherthecentercompartmentcontainingthecellbodieswasprovidedwith1μg/NGF/mlornoNGF.Furthermore,neuritegrowthwasnotapparentinNGF-deprivedcentercompartments,whileneuritesexposedtoNGFregeneratedafterneuritotomyinthesidecompartments.ThissuggeststhatthepromotionofgrowthbyNGFwaslargely(perhapsentirely)confinedtothedistalneuriteregionsdirectlyexposedtoextracellularNGF,whilethegrowthofmoreproximalneuriteregions(whichmaybepresumedtocontainNGFenroutetothesomaviaretrogradetransport)waspromotedlittleornotatallintheabsenceofextracellularNGF.TheresultsofthisworkshowthattheNGFconcentrationinthelocalenvironmentoftheneuritesexertsimportantcontrolovertheirlocalgrowthandstronglysupportsthehypothesisthattissueNGFlevelsregulatesympatheticinnervationinvivo.

[学科分类] 生物科学（综合）