Acetylcholine and its metabolic enzymes in developing antennae of the moth, Manduca sexta☆

[摘要] Antennaeofthemoth,Manducasexta,arethicklypopulatedwithsensoryneurons,whichsendaxonsthroughantennalnervestothebrain.Theseneuronsarisebycelldivisionsanddifferentiatesynchronouslyduringthe18daysofmetamorphosisfrompupatoadult.Biochemicalstudiessupportthehypothesisthatantennalneuronsuseacetylcholine(ACh)asaneurotransmitter:(1)Antennaeincubatedwith[14C]cholinesynthesizeandstore[14C]ACh;severalothertransmittercandidatesdonotaccumulatedetectablywhenappropriateradioactiveprecursorsaresupplied;(2)antennaeandantennalnervescontainendogenousACh;and(3)extractsofmatureantennaecontaincholineacetyltransferase(ChAc)andacetylcholinesterase(AChE)withpropertiessimilartothosereportedfortheenzymesfromotherarthropods.LevelsofACh,ChAc,andAChEbegintoincreaseinantennaesoonafterthesensoryneuronsare“born.”Levelsriseexponentiallyforoveraweekastheneuronsdifferentiateandthenreachaplateau,ataboutthetimetheneuronsreachmorphologicalmaturity,thatismaintainedintoadulthood.Incontrast,levelsofcarnitineacetyltransferase,cholinesterase,andsolubleprotein,presumablynotconfinedtonervoustissue,changelittleduringmetamorphosis.LevelsofACh,ChAc,andAChEriseinanintracranialsegmentofantennalnerveataboutthesametimeasintheantenna,indicatingthataxonscantransportneurotransmittermachineryatanearlystageintheirdevelopment.

[学科分类] 生物科学（综合）