Effect of agonist on gamma-aminobutyric acid B receptor subunit expression in the hippocampus of epileptic rats

(整期优先)网络出版时间:2009-08-18
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BACKGROUND:Anaminoacidimbalancehasbeenconsideredtoberesponsibleforepilepsypathogenesis.Gamma-aminobutyricacid-Breceptor(GABA_BR)inhibitsvoltage-sensitivecalciumionchannelsandGABAorglutamicacid(Glu)neurotransmitterrelease,whichpromotesorinhibitsonsetanddevelopmentofepilepsy.OBJECTIVE:ToexploretheeffectofbaclofenonGBR1aandGBR2mRNAexpressioninthehippocampusofepilepticratsfollowingkainicacid(KA)induction,andtostudytheadaptabilityofGABA_BRsubunits.DESIGN,TIMEANDSETTING:Arandomized,controlled,animalexperimentbasedonmolecularbiologywasperformedattheLaboratoryResearchCenterofSecondHospitalAffiliatedtoSoochowUniversityfromNovember2005toMarch2006.MATERIALS:KAwasprovidedbySigma,USA.InsituhybridizationdetectionkitofGBR1aandGBR2wasprovidedbyWuhanBosterBiologicalTechnology,China.GABA_BRagonist(baclofen)wasprovidedbySigma,USA.METHODS:Forty-fourepilepticratswererandomlyallocatedtoepileptic(n=28)anddrugintervention(n=16)groups.Theepilepticgroupwasfurtherpidedintopost-epilepticsubgroupsatdifferenttimepoints:6,12hours,1,3,7,15,and30days(n=4).Thedruginterventiongroupwasfurtherpidedintointerventioncontrolssubgroupsatvarioustimepoints:6hours,1day,and3days(n=4).Fouradditionalratswereconsideredthenormalcontrolgroupandnotmodeled,butwereinjectedwithsalineinthehippocampalCA3region.MAINOUTCOMEMEASURES:GBR1aandGBRmRNAexpressionwasdetectedintherighthippocampalCA1,CA3,anddentategyrus(DG)areasofthecontrol,epileptic,andinterferencegroupsatvarioustimeintervalsaccordingtoinsituhybridizationresults.RESULTS:(1)Duringtheearlystageofepilepsy(6and12hours),GBR1aandGBR2mRNAexpressionwasdecreased,andexpressionwaslessthanthecontrolgroupatonedayafterKAinduction(P<0.05).mRNAexpressionwasincreasedintheDG,butwasgreaterthanthecontrolgroupatday3(P<0.05).ExpressioninthehippocampalCA1andCA3regi