Expression Of Gamma-aminobutyric Acid A Receptor Subunit Alpha1and Gamma2in Hippocampus And Effect Of Neuroethology After Recurrent Seizures Of Immature Rats

Objective: To explore the effects of recurrent seizures on the gamma-aminobutyricacid A receptor subunit alpha1and gamma2and the impact of long-term brain damage，inorder to understand the gamma-aminobutyric acid A receptor (GABA_Areceptor) subunitthe role of seizures in the immature brain.Methods：725-day-old(P5) Waster rats were divided randomly into two groups：recurrent seizure group(RS group)and the control group（CONT group）.Rats in RS groupdaily inhaled flurothyl induced seizures five times, each time interval2h,5consecutivedays; rats in l control group, the same but not inhaled flurothyl. Then to examined neuralreflex(Plane righting test, forelimb suspension test, cliff avoidance test, negative geotaxistest), open field test, balance beam experiments, Morris water maze test to evaluate theneurobehavioral. Western blot and fluorescence quantitative RT-PCR was employed todetermine GABA_A-R subunits α1and γ2expression at different times points(1d,25d,60d)after the last convulsions.Result:1、behavior analysis：(1) cliff avoidance: The time of cliff avoidance in RSwas longer than CONT(P<0.05),the difference was statistically significant.(2) Negativegeotaxis: the RS rats inverted180°C required time was significantly longer than in theCONT group (P <0.05), the difference was statistically significant.（3）Open-field test: thecentral grid residence time of RS group longer than the CONT group(P<0.05), thedifference was statistically significant; the across grid of RS group compared with theCONT group was significantly reduced (P <0.01), the difference was statisticallysignificant.（4）Balance beam test: the average score of the RS rats was significantly lowerthan the CONT group (P<0.05),the difference was statistically significant（5）Morris watermaze test：①The average latencies of all rats were reduced by degree from D1to D5.the Stage incubation period longer in RS group than that in CONT group at D3andD4(P<0.05);the difference was statistically significant， the Stage incubation periodsignificantly longer in RS group than that in CONT group at D5(P<0.01),the differencewas statistically significant.②S earch strategy:The CONT rats mainly use straight linesand tends strategy, RS rats is more of an edge and random type.③Rats in RS group thefrequency of through the platform was significantly reduced compared to the CONTgroup(P<0.05).2、Western blot analysis：With the growth of day-old,the protein expression levels ofGABA_Areceptor alpha1and gamma2subunit gradually increased. At After the lastconvulsions1d, the protein expression of GABA_Areceptor alpha1subunit of rats in RSgroup was no significant difference compared to CONT group, the protein expression ofGABA_Areceptor gamma2subunit in RS group was significantly lower than that in thecontrol group (P<0.01).At After the last convulsions25d and60d,the protein expression ofGABA_Areceptor alpha1and gamma2subunit in RS group was lower than that in thecontrol group (P<0.05).3、RT-PCR analysis：With the growth of day-old, the protein expression increased ofGABA_Areceptor alpha1and gamma2sub-unit mRNA. At After the last convulsions1d,Convulsions rats GABA_Areceptor alpha1subunit mRNA expression levels in thehippocampus was significantly lower than that in the control group (P<0.01),gamma2subunit mRNA expression in the hippocampus with the control group showed nosignificant difference (P>0.05).At After the last convulsions25d,Convulsions ratsGABA_A receptor alpha1and gamma2subunit mRNA expression levels in thehippocampus was significantly lower compared with the control group (P <0.05).At Afterthe last convulsions60d,The seizure group rat GABA_A receptor alpha1subunit mRNAexpression levels in the hippocampus compared with the control group was significantlylower (P <0.05), gamma2subunit mRNA expression levels in the hippocampus than in thecontrol group was significantly lower (P <0.01).Conclusions:(1) Flurothyl can induced Waster rats recurrent seizures, recurrentseizure will have some degree of brain damage in the neonatal rat, resulting in the ratgrowth retardation, reflex delay, and generates adulthood decreased ability to adapt newenvironment, as well as long-term learning and memory ability damage.(2) In hippocampalof immature newborn rats the GABA_Areceptor alpha1and gamma2subunits related genes be affected in Short term after recurrent seizures, the effect will long-term existenceand affect protein expression, which may be long-term impact on the brain development ofneuronal function.(3) Recurrent seizures of immature rat cause long-term neurobehavioralchanges and cognitive impairment, also changed adulthood GABA_Areceptor subunit alpha1and gamma2subunit expression; the long-term change of subunit expression participatein learning and memory impairment, and produce long-term effects on brain function.