Metabolic stabilization of acetylcholine receptors at newly formed neuromuscular junctions in rat☆
[摘要] Theturnoverofacetylcholinereceptors(AChRs)wasstudiedatdevelopingmotorendplatesinembryonicratdiaphragmandatnewlyformedectopicendplatesinsoleusmusclesofadultrats.Afterthereceptorswerelabeledinsituwith125I-α-bungarotoxin,therateoflossofboundtoxinwasdeterminedbyautoradiographyofsinglemusclefibersandwasusedtocalculatetheturnovertimeofAChRs.Anew,convenientmethodforpreparinglargenumbersofsinglemusclefibersisdescribed.AChRsinextrajunctionalregionsofembryonicdiaphragmsturnoverwithashorthalf-time(24hr)similartothatofAChRsinculturedmyotubesandofextrajunctionalAChRsindenervatedadultmuscle.AChRsinnewlyformedclustersindevelopingmuscleandinectopicallyinnervatedadultmusclealsoturnoverwithshorthalf-times.Withinafewdays,however,theturnovertimeincreasestovaluescharacteristicofadultjunctionalreceptors(6–10days).Transectionofthenerveatnewlyformedectopicendplatespreventsthechange.ThemetabolicstabilizationofAChRsatmotorendplatesinratmusclesisthusarelativelyearlyeventinsynapseformation;itcoincidesneitherwiththeclusteringofreceptors,whichprecedesit,norwiththedecreaseinAChRchannelopentimewhichhasbeenshowntooccurpostnatally.
[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]
