Properties of electrotonic junctions between embryonic cells of Fundulus☆
[摘要] CellsisolatedfromblastulaeoftheteleostFunduluscanbereaggregatedinpairsinphysiologicalsaltsolution.Thecellpairsusuallybecomeelectricallycoupled.Unlikemanycoupledcellsofadulttissues,injectedfluoresceindoesnotpassbetweenthesecellsindetectableamounts,althoughitcanenterthecellswhenexternallyapplied.Glutaraldehydefixationrapidlyandgreatlyincreasescouplingresistance,butcausesonlymoderateincreasesincellresistanceexclusiveofthecouplingpathway;thusfixationdecouplescells.Electricalmeasurementsdemonstratethatfixationdoesnotdisruptzonulaeoccludentesinblastulaeorgastrulae.ElectronmicroscopyrevealsthattheappositionalregionbetweenreaggregatedcellpairsispenetratedbyLa(OH)3appliedwiththefixative.Therearealsoextensiveregionsofcloseappositionbetweenthecellmembranes.Thecombineddataindicatethattheseembryoniccellsarecoupledbywayofspecialized,electrotonicjunctionsratherthanaregionofextracellularspacebetweenthemthatiswalledoffbyazonulaoccludens.Amorphologicalsubstrateforthesejunctionsisprovidedbythecloseappositionsseenelectronmicroscopically.Therelativelyrestrictivepermeabilityoftheelectrotonicjunctionsbetweenembryoniccellsmayallowsmallionstofunctionasintercellularsignalingmoleculeswhilerestrictingmovementoflargermoleculesinvolvedinintracellularcontrols.
[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]
