Distribution of adrenergic nerves and changes in neuromuscular transmission in the mouse vas deferens during postnatal development
[摘要] Fluorescenceduetocatecholaminesisfirstobservedinlongitudinallyorientatednervebundlesduringthefirstpostnatalday.Finefluorescentnervesarepresentwithinthecircularmusclecoatbythepostnatalday5andinthelongitudinalcoatfromaboutday9.Thedensityofthisinnervationincreasesrapidlywiththedevelopmentofthemusclecoats.Therestingmembranepolarizationofthesmoothmusclecellsincreasedwithage,from67mVat10daysto74mVat6months.Excitatoryjunctionpotentials(EJP's)inresponsetointrinsicnervestimulationwerenotobservedformiceoflessthan18days.TheEJP'sevokedinvasafrommiceoffrom18daysto25–30daysdecayedfrompeakamplitudeinupto160msec,comparedtoabout60msecinvasafromadultmice.Incontrast,therisetimeoftheEJPandthesynapticdelayfortransmissionwerethesameforEJP'sinvasafrommiceofallages.IthasbeenshownthatthetimeofdecayoftheEJPisnotdeterminedbyinactivationoftransmitterbyuptakeintoperipheralnervefibers.TheconfigurationoftheEJP'swasconsistentfrom30days,whichcorrespondswiththeonsetofpubertyinmice.Thepresenceofnervefiberscontainingcatecholamines,observedeitherbyfluorescenthistochemicalmethodsorassmallgranularvesiclesinelectronmicroscopicstudies,doesnotnecessarilyindicatethepresenceofafunctionaltransmissionprocessindevelopingtissue.
[发布日期] [发布机构]
[效力级别] [学科分类] 生物科学（综合）
[关键词] [时效性]
