简介：Prestinhasbeenidentifiedasamotorproteinresponsibleforouterhaircell(OHC)electromotilityandisexpressedontheOHCsurface.PreviousstudiesrevealedthatOHCelectromotilityanditsassociatednonlinearcapacitanceweremainlylocatedattheOHClateralwallandabsentattheapicalcuticularplateandthebasalnucleusregion.ImmunofluorescentstainingforprestinalsofailedtodemonstrateprestinexpressionattheOHCbasalendsinwhole-mountpreparationoftheorganofCorti.However,therelacksadefinitivedemonstrationofthepatternofprestindistribution.TheOHClateralwallhasatrilaminateorganizationandiscomposedoftheplasmamembrane,corticallattice,andsubsurfacecisternae.Inthisstudy,thelocationofprestinproteinsindissociatedOHCswasexaminedusingimmunofluorescentstainingandconfocalmicroscopy.Wefoundthatprestinwasuniformlyexpressedonthebasolateralsurface,includingthebasalpole.Nostainingwasseenonthecuticularplateandstereocilia.Whenco-stainedwithamembranemarkerdi-8-ANEPPS,prestin-labelingwasfoundtobeintheouterlayeroftheOHClateralwall.Afterseparatingtheplasmamembranefromtheunderlyingsubsurfacecisternaeusingahypotonicextracellularsolution,prestin-labelingwasfoundtobeintheplasmamembrane,notthesubsurfacecisternae.ThedatashowthatprestinisexpressedintheplasmamembraneontheentireOHCbasolateralsurface.

简介：ObjectiveUsingopticalimaginginbrainstemslices,westudiedevokedresponsesinthemousecochlear(CN)andvestibular(VN)nuclei.MethodsTheuseofopticalimagingallowedustovisualizethespatiotemporalpatternsofexcitatorypropagationintheCNandVN.OpticalrecordingscandifferentiateexcitatorypropagationintheventralCN(VCN)fromthatinthedorsalCN(DCN).Furthermore,weassessedtherelativedistributionofNMDAandnon-NMDAreceptorsintheseregionsusingtheglutamateantagonistsAPV(NMDAreceptorantagonist)andCNQX(non-NMDAreceptorantagonist)inmousebrainstemslicesduringpostnataldays1to3.ResultsTheaveragesensitivitytoAPVwas99.1%intheVCN,76.0%intheDCNand64.9%intheVN.TheaveragesensitivitytoCNQXwas0.9%intheVCN,24.0%intheDCNand35.1%intheVN.TheseresultsindicatethattheeffectofAPVdominatedintheVCN,whilebothAPVandCNQXwereeffectiveantagonistsintheDCNandVN.IntheVN,thedistributionofAPV-andCNQX-sensitivecellswasalmostcompletelyuniform.However,intheDCNthedistributionofAPV-andCNQX-sensitivecellswashighlycomplex.TheareathatwasmoresensitivetoCNQXwaslocatedinthesuperficiallayeroftheDCNwhiletheareawithahighersensitivitytoAPVwaslocatedprogressivelyinthedeeplayer.ConclusionThisopticalrecordingdatasuggeststhatthereisadifferentialdistributionofNMDAandnon-NMDAreceptormediatedneurotransmissionintheVCN,DCNandVN.

简介：Postauricalinjectionoftherapeuticswasrecentlyappliedinclinicalpracticetotreatinnereardiseasesbasedonsupposedexistenceofadirectchannelfromthepostauricalareatotheinnerear.Doubtingontheassociatedreportsandaimingtoprovideevidenceontheinnerearuptakemechanism,thepresentstudytrackedthedynamicdistributionofgadolinium-tetra-azacyclo-dodecane-tetra-aceticacid(Gd-DOTA)inratinnerearsafterpostauricalinjectionusingMRI.Atargetedtympanicmedialwalldeliverywasutilizedascontrol.Theresultsshowedthat,attheearlytimepointsafterpostauricalinjection,Gd-DOTAdistributedmainlyintissuessurroundingthebulla,temporalboneandskullandneckspace.Intheinnerear,therewasgradualuptakeofGd-DOTAonboththeipsilateralandcontralateralsideswithequalsignalintensities.Therewasnosignofdirectchannelcarryingtheagentfromthepostauricalareatotheinnerear.TargetedtympanicmedialwalldeliveryinducedsignificantlygreateruptakeofGd-DOTAintheinnerearthandidpostauricalinjection.At30minpost-administration,targetedtympanicmedialwalldeliveryyielded4.6-foldshighersignalintensitythandidpostauricalinjection.ThetotaldoseofGd-DOTAdeliveredbythetargetedtympanicmedialwallapproachwasonly0.1%ofthatdeliveredbypostauricalinjection.Inconclusion,postauricalinjectionisasystemicadministration,whichissimilartohypodermicinjection,ratherthanafocaldeliverymethod.Bycontraries,targetedtympanicmedialwalldeliveryinducesfastandabundantuptakeofGd-DOTAintheipsilateralinnerearwithoutsignificantdistributioninunwantedareas.