ApplicationNotes | Immunohistochemistry:1:250-1:2500byPAP(seesuggestedprotocolbelow).
Optimalworkingdilutionsmustbedeterminedbytheenduser.
PROTOCOLforAcetylcholineDetectionbyImmunohisto/cytochemistry.Exampleforaratbrain.
1.SOLUTIONSTOBEPREPARED-Solutionmustbepreparedasneeded.
SolutionA:0.5Mglutaraldehyde,0.1M2-nitrobenzylalcohol,10g/LsodiummetABIsulfite,0.1Mcacodylate,0.01Msodiumbromide,pH10.7.
SometimesaprecipitatemayformwhilemakingsolutionA.Toavoidthis,firstprepareamixturewith1.0Mglutaraldehydeand0.2M2-nitrobenzylalcohol.Prepareasecondmixturewith20g/Lsodiummetabisulfiteand0.2Mcacodylate;addsodiumbromidetoobtainpH10.7.Thencombinethetwomixturesinequalpartswhilestirring.
SolutionB:0.05MTris,10.0g/Lsodiummetabisulfite,pH7.4.(*)
2.RATPERFUSION-TheratisanaesthetizedwithsodiumpentobarbitalorNembutalandperfusedintracardiallythroughtheaortausingapumpwithSolutionA(200-300mL/min).
3.POSTFIXATION:2hoursin0.5Mglutaraldehydesolution,(pH7.5)withoutthe2-nitrobenzylalcohol,then4softwashesinsolutionB.
4.TISSUESECTIONING:Vibratomeorcryostatsectionscanbeused.
Thesectionsarewashed4timesinsolutionB,andincubatedfor1hourat37°CinsolutionBcontaining0.2%TritonX100,plus1%nonspecificserum.
5.APPLICATIONOFACETYLCHOLINEANTIBODY:Useafinaldilutionof1:500-1:2,500inSolutionBcontaining0.2%TritonX100and1%non-specificserum.Incubate12sectionsper2mLdilutedantibodyovernight,+4°C.Thenwashthesectionsthreetimesfor10minuteseachinSolutionB.(Notethattheantibodymaybeusableatahigherdilution.Thisshouldbeexploredtominimizethepossibilityofhighbackground.Additionally,notethatachangeinthebufferingsystemasindicatedintheprotocolmaychangethebackgroundandantibodyrecognition).ThespecificreactionisthenrevealedbyPAPprocedure.
6.SECONDANTIBODY:Incubatethesectionswitha1:50to1:200dilutionofgoatanti-rabbitinSolutionBcontaining1%non-specificserumforeither3hrsat20°Cor2hrat37°C.Thenwashthesections,3times,for10minuteseachwithSolutionB.
7.PAP:Incubatethesectionswiththeappropriatedilutionofperoxidaseanti-peroxidase(forfreefloatingmethod)inSolutionBcontaining1%non-specificserumfor1-2hoursat37°C.Thenwashsections3timesfor10mineachinsolutionB.
8.VISUALIZATION:Theantigen-antibodycomplexesarevisualizedusingDAB-4-HCl(25mg/100mL)(orotherchromogen)in0.05MTrisandfiltrated;0.05%hydrogenperoxideisadded.Incubatethesectionsfor10minutesatroomtemp.Stopthereactionbytransferringthesectionsto5mL0.05MTris.WashtissuewithsolutionDusing2,10minwashes.Mountsectionsonchrome-alumcoatedslides.Dryovernightat37°C.Rehydratesectionsusingconventionalhistologicalprocedures.Coverslipusingrapidmountingmedia. |