Target-Independent Specification of Proprioceptive Sensory Neurons

Developmental Biology

Robert A Oakley¹  Beverly A Karpinski¹ 

[1] Department of Anatomy and Cell Biology, The George Washington University Medical Center, Washington, DC, 20037

关键词: neurotrophins;    neurotrophin-3;    sensory neurons;    cutaneous afferents;    muscle afferents;    proprioceptive afferents;    motor neurons;    spinal cord projections;    fate specification;    differentiation;   

DOI  :  10.1006/dbio.2002.0775

学科分类：生物科学（综合）

来源: Academic Press

【 摘 要 】

Previousstudiesinthechickembryohaveshownthatsensoryneuronsfailtoinnervatemuscleintheabsenceofmotorneurons.Instead,motorneurondeletioncausesmoresensoryaxonstoprojecttotheskin.Weusedthisexperimentalparadigmtodeterminewhensensoryneuronsarespecifiedtobecomeproprioceptiveafferents.Experimentalembryosweretreatedwitheithersalineorexogenousneurotrophin-3(NT-3)topromotethesurvivalofproprioceptiveafferents.Insaline-treatedembryos,motorneurondeletioncausedanincreaseinsensoryneuronapoptosisonthedeletedside,aneffectreversedbyNT3.Motorneurondeletionalsoeliminatedthesartoriousmusclenerve,aspreviouslyreported.InNT3-treatedembryos,thisalterednervepatternwasaccompaniedbytheenlargementoftheadjacentcutaneousnerve.TheseembryoswerefurtheranalyzedbyusingimmunohistochemistryfortrkC(areceptorforNT3)retrogradeandtransganglioniclabeling.Ourresultsshowthat,followingmotorneurondeletion,moretrkC+afferentsprojectincutaneousnervesonthedeletedsideofNT3-treatedembryos.Transganglioniclabelingdemonstratedthatatleastsomeoftheseneuronsmadespinalprojectionsthataretypicalofproprioceptiveafferents.Theseresultsthereforeindicatethattheproprioceptivephenotypeisspecifiedpriortotargetinnervationandthattheseneuronscanretaintheiridentitydespiteprojectingtoinappropriate(cutaneous)targets.

【 授权许可】

Unknown