慢性强直电刺激右侧尾壳核诱导大鼠癫痫样电图和行为发作特征

目的 :慢性强直电刺激右侧尾壳核 (CPu)诱导大鼠电图和行为癫痫点燃样现象 ,观察CPu或海马 (HPC)网络异常的靶向癫痫样行为表达特征。方法 :共用雄性SD大鼠 58只。强直电刺激 ( 60Hz ,0 .4～ 0 .6mA ,2s)大鼠右侧CPu或右侧前背HPC ,1time/d ,连续刺激 7～ 12d。结果 :①CPu电图节律性尖波样发放或HPC电图阵发性高幅失律。②CPu或HPC刺激组大鼠均可以出现原发性、继发性或点燃样湿狗样抖动 (wetdogshakes ,WEDS)、直立、洗面、好静、咀嚼和节律性点头等行为发作。③CPu刺激组大鼠原发性WEDS频率明显低于HPC刺激组大鼠( 2 .10± 0 .12和 2 .89± 0 .2 0times/min ,P <0 .0 1) ,继发性WEDS频率明显高于HPC刺激组大鼠 ( 1.2 3± 0 .11和0 .78± 0 .0 6times/min ,P <0 .0 1)。④CPu刺激组大鼠点燃样效应出现之前的行为静止天数较长。结论 :如同刺激HPC一样 ,慢性电刺激大鼠CPu可以出现类似的癫痫样行为发作。结果提示 :CPu功能异常有可能成为癫痫发作的起源病灶 ,与HPC类似 ,参与了颞叶癫痫电网络的重建 ,具有特征性的癫痫样靶行为表达     

海马胆囊收缩素对大鼠癫痫发作的影响及其机制

目的和方法：采用原位杂交技术,观察遗传性听源性癫痫易感大鼠海马内ＣＣＫｍＲＮＡ表达的改变及少我注射ＣＣＫ３及其受体阻断剂对大鼠癫痫发作的影响。结果：（１）癫痫发作大鼠海马内ＣＣＫｍＲＮＡ表达明显增强（Ｐ〈０．０５－０．０１）,但癫痫反复发作的大嫌海马内ＣＣＫｍＲＮＡ表达的较癫痫发作一次大鼠明显减少（Ｐ〈０．０５）,海马ＣＡ主射Ｌ３６５后,ＣＣＫ８压抑癫痫发作的作用消失（Ｐ〈０．０１）。结论：ＣＣＫ     

谷氨酸转运体对癫痫持续状态大鼠突触可塑性的影响

探讨了在大鼠癫痫持续状态模型,谷氨酸转运体功能改变对突触可塑性的影响.健康成年雄性Wistar大鼠((304.06±13.79)g)随机分为5组,短期癫痫实验组(SE)及其对照组(SC),长期癫痫实验组(LE)及其对照组(LC),健康对照组(Sham).匹鲁卡品皮下注射(25 mg/kg)建立癫痫模型,建模14天后SE和LE组大鼠右侧海马内注射谷氨酸转运体抑制剂TBOA(7.5 nmol,lμ1),SC和LC组注射相同剂量的人工脑脊液.注射药物2 h后,SE和SC组检测脑电图(EEG):药物注射后2周,LJ巳和LC组检测内嗅区前穿通纤维-海马齿状回(PP-DG)长时程增强(LTP)和EEG.电生理学检测后动物灌流取脑做Fluoro-Jade-B染色.结果表明:脑电功率谱分析,SE组theta波段能量较sc组明显下降(P＜0.05),LE组与其对照Lc组相比,EEG的也theta波段能量无明显差异(P＞0.05);LTP检测显示.LE组与对照LC组相比,兴奋性突触后电位(EPSP)斜率升高(P＜0.01);Fluoro-Jade-B染色显示,LE组与对照LC组相比,给予TBOA 2周后细胞变性明显增加.结果提示,癫痫持续状态后,海马神经元损伤,TBOA导致谷氨酸转运体功能障碍,加重癫痫所至神经元损伤,对海马区突触可塑性产生影响.     

低铅暴露对大鼠海马突触可塑性范围的影响

长时程增强(LTP)和长时程抑制(LTD),作为突触可塑性变化的两种主要形式,被认为是学习记忆的可能机制.突触可塑性范围可以定量的表征突触可塑性的变化.应用在体电生理技术,在同一只动物上记录LTP和LTD,研究了发育过程中慢性铅暴露对大鼠海马齿状回颗粒细胞突触可塑性范围和双脉冲易化的影响.对照组的LTP、LTD的幅度分别是187.9±6.2%(n＝7),85.2±1.6%(n＝7),而铅处理组分别为140.5±1.2%(n＝7),102.8±3.8%(n＝7).与对照组相比,铅处理组的LTP的幅度降低了47.4%,LTD的诱导几乎完全被铅损伤.先诱导出LTP后再通过低频刺激则可以在铅处理组诱导出LTD(81.5±2.2%(n＝7)),但远远小于对照组(66.8±4.3%(n＝7)).对照组突触可塑性范围是103.1±11.5%(n＝7),是铅处理组突触可塑性范围(37.7±9.6%(n＝7))的2.7倍.在对照组,双脉冲易化反应是从脉冲间隔20ms时开始,而铅处理组则是从50ms开始.当脉冲间隔为70ms时,两组的双脉冲易化幅度均达到最大值,但易化的强度有显著的差异,分别为211.6±32.2%(n＝7),11.1±26.9%(n＝7).结果表明铅显著地抑制了大鼠海马齿状回颗粒细胞的双脉冲易化效应,降低了双脉冲易化的间隔范围和突触可塑性范围.这可能是铅损伤学习记忆功能的机制之一.     

海马mu型阿片肽受体介导大鼠癫痫发作敏感性形成

为探讨海马mu型阿片肽受体介导癫痫发作敏感性形成的作用,实验采用微渗透泵技术,观察大鼠腹侧海马注射mu型阿片肽受体激动剂PL017(2.09、2.59、3.29μg/μ1)、拮抗剂β-funaltrexaminehydrochloride(β-FNA、0.88、1.10、1.35μg/μl)对红藻氨酸(kainic acid,KA)诱导癫痫发作的干预作用.PL017能够明显缩短癫痫发作潜伏期、增加癫痫发作级别(P＜0.05),β-FNA则可显著延长癫痫发作潜伏期、降低发作级别(P＜0.01);PL017和β-FNA的干预作用均表现出剂量依赖效应.结果表明,海马mu型阿片肽受体具有促进KA诱导的癫痫发作敏感性形成作用.     

胰岛素对阿尔茨海然病大鼠血浆血小板活化因子及海马突触可塑性的影响

目的：探讨胰岛素对阿尔茨海默病（AD）大鼠血浆血小板活化因子（PAF）及海马突触可塑性的影响。方法：将30只SD大鼠随机分为治疗组（10只）、模型组（10只）、假手术组（10只）,采用侧脑室注射链脲霉素（STZ）建立AD大鼠模型。治疗组大鼠皮下注射胰岛素（0．1U／kg）,模型组及假手术组大鼠皮下注射等体积的生理盐水（1mL／kg）。通过Morris’s水迷宫实验评估各组大鼠的认知功能,酶联免疫吸附法测定各组大鼠的血浆PAF含量,免疫印迹法检测大鼠海马突触素的表达。结果：治疗4周后,模型组大鼠连续4天水迷宫的潜伏期均显著长于假手术组大鼠（P〈0．05）,而治疗组大鼠第2、3、4天水迷宫潜伏期均较模型组显著缩短（P〈0．05）,但仍长于假手术组大鼠（P〈0．05）;模型组大鼠的血浆PAF含量和海马突触素的表达均显著高于假手术组,而治疗组大鼠的血浆PAF含量和海马突触素的表达均显著低于模型组（P〈0．05）,差异均有统计学意义（P〈0．05）。结论：皮下注射胰岛素可改善AD大鼠的认知功能,这可能与其下调AD大鼠血浆PAF水平以及保护突触的可塑性有关。     

海马齿状回神经再生对WKY大鼠抑郁样行为的影响*

目的:观察海马齿状回(DG)神经再生对成年Wistar Kyoto(WKY)大鼠抑郁样行为的影响。方法:实验共分三个组(n = 10):①正常对照(Wistar)组:选取 9 周龄Wistar大鼠,给予生理盐水 3 周(10 mg/kg, 灌胃);②抑郁模型(WKY)组:选取同龄WKY大鼠并经行为学测定后筛选出抑郁大鼠作为抑郁模型组,给予生理盐水 3 周(10 mg/kg, 灌胃);③阳性对照(AMI+WKY)组:选取同龄WKY抑郁大鼠,给予阿米替林(AMI) 3 周(10 mg/kg, 灌胃)。选用免疫荧光染色细胞增殖标记物Ki67、未成熟神经元标志物DCX检测大鼠的海马神经再生水平;应用糖水偏好实验(SPT)、旷场实验(OFT)和强迫游泳实验(FST)检测各组大鼠的抑郁样行为学变化。结果:①WKY抑郁大鼠海马DG区细胞增殖标志物Ki67⁺细胞数和未成熟神经元标志物DCX⁺细胞数较Wistar大鼠分别降低了 33.0%(P＜0.01)和39.2%(P＜0.01);阿米替林给药后使抑郁大鼠海马DG区Ki67⁺细胞数和DCX⁺细胞数分别增加了43.8%(P＜0.01)和46.7%(P＜0.01)。②与Wistar大鼠相比,WKY抑郁大鼠糖水偏好程度明显降低(P＜ 0.01),旷场实验中运动总距离显著缩短(P＜0.01)和中心停留时间显著减少(P＜0.01),强迫游泳实验中不动时间明显延长(P＜ 0.01);阿米替林治疗可显著改善WKY大鼠的上述抑郁样行为。结论:①成年WKY抑郁大鼠的海马神经干细胞的增殖和分化能力较正常对照组显著降低,提示成年WKY抑郁大鼠的神经再生受损;②改善海马受损的神经再生可以部分逆转成年WKY大鼠的抑郁样行为。     

红藻氨酸癫痫大鼠海马GFAP基因调控蛋白表达的变化

目的和方法：用Southwestern印迹从红藻氨酸（KA）癫痫大鼠海马结构中筛选调控胶质原纤维酸性蛋白（GFAP）基因表达的DNA结合蛋白;并观察其在海马内表达变化的规律,旨在从基因调控水平深入探讨癫痫反复发作形成的神经病理学机制。结果：Southwestern印迹的实验显示海马结构内有两种调控GFAP基因表达的序列特异的DNA结合蛋白,分子量分别为39kDa和35.5kDa;KA后1d,两种调控蛋白的表达即开始增加,5－7d时表达显著增加,3周时表达最多,3个月时表达仍很高。结论：KA通过上调调控GFAP基因表达的转录因子,使海马GFAP过量表达,提示该转录调控因子很可能参与一次KA后癫痫反复发作的形成。     

C57/BL6癫痫小鼠海马齿状回DCX和GFAP表达的时程变化

目的：观察C57/BL6癫痫小鼠海马神经元DCX和GFAP表达的时程变化,为神经元发生,发育和星形胶质细胞的变化提供理论基础。方法：应用海人藻酸建立小鼠癫痫模型,应用免疫荧光组织化学方法检测海马齿状回不同时间点双皮质醇,胶质纤维酸性蛋白的表达。结果：与对照组相比,癫痫发生后3天7、天,海马齿状回DCX阳性神经元的免疫荧光强度明显增强;GFAP阳性神经元的免疫荧光强度在癫痫发生后持续的一周内较对照组均见明显持续表达增强。结论：小鼠癫痫后会引起海马星形胶质细胞的活化,同时发病早期神经元已经出现再生标记物的增加。     

发育期铅、铝共同暴露与单独铝暴露引起的大鼠海马突触可塑性损伤的差异

铝近年来被认为是一种神经毒,可以引起动物和人认知及行为的损伤。应用在位电生理技术发现慢性0,2％氯化铝暴露(从出生到成年)损伤了大鼠海马齿状回归一化群峰电位(Ps)的长时程增强(L1]P),明显降低了兴奋性突触后电位(fEPSP)LTP的去长时程增强(DP)和归一化PS LTP的DP幅度,而对fEPSP的LTP影响不大。铅是人们公认的神经毒,能造成中毒者智力、认知和行为的损伤。铅、铝作为常见的环境毒,在我们周围并存。探讨了发育期的铅、铝共同暴露和单独铝暴露所造成的突触可塑性损伤的差异。结果表明,发育期的铅、铝共同暴露明显比单独铝暴露引起的归一化PS LTP和PS LTP的DP的损伤要严重,并引起了fEPSP的LTP损伤。     

Lithium enhances long-term potentiation independently of hippocampal neurogenesis in the rat dentate gyrus

We measured the temporal and spatial profiles of neural precursor cells, hippocampal long-term potentiation (LTP), and signaling molecules in neurogenesis-induced adult rats. Chronic lithium treatment produced a significant 54% and 40% increase in the numbers of bromodeoxyuridine [BrdU(+)] cells after 12 h and 28 days, respectively, after treatment completion in the dentate gyrus (DG). Both LTP obtained from slices perfused with artificial cerebrospinal fluid (ACSF-LTP) and LTP recorded in the presence of bicuculline (bicuculline-LTP) were significantly greater in the lithium group than in the saline controls. Although the number of BrdU(+) cells, approximately 90% of which were double-labeled with a neural marker neuronal nuclear protein, were markedly increased in the granule cell layer (GCL) 28 days after the completion of the 28-day lithium treatment, the magnitude of LTP observed at this time was similar to that observed 12 h after completing the 28-day lithium treatment. However, protein levels of calcium and calmodulin-dependent protein kinase II, p-Elk and TrkB were highly elevated until 28 days after the 28-day lithium treatment. Acute lithium treatment for 2 days also enhanced LTP, which was accompanied by the elevated expression of p-CREB, but not by neurogenesis. Our results suggest that the enhancement of LTP is independent of the increased number of neurons per se and it is more closely associated with key molecules, which are probably involved in neurogenesis.     

Successive alterations of hippocampal gamma-aminobutyric acid B receptor subunits in a rat model of febrile seizure

Febrile seizure (FS) is a frequently encountered seizure type in childhood. Changes of brain function following FS have clinical importance. The recently identified gamma-aminobutyric acid B receptor (GABA(B)R) is a metabotropic receptor of GABA. In this study, we used a rat model of recurrent FS to investigate the changes of GABA(B)R1a and GABA(B)R2 subunits in hippocampus after recurrent FS by using Western blot, quantitative RT-PCR, double immunofluorescence, in situ hybridization and immunoprecipitation/Western blot. After treatment of hyperthermia and the presence of induced seizures once every 2 days for 10 times, GABA(B)R1a and GABA(B)R2 subunits in hippocampus were decreased after 24 h of the last treatment. The decrease of GABA(B)R1a lasted for 15 days but that of GABA(B)R2 persisted for more than 30 days. The binding of GABA(B)R1a to GABA(B)R2 in hippocampus was also decreased significantly after 24 h of the last treatment and lasted for more than 30 days. In situ hybridization showed that GABA(B)R1a mRNA was significantly decreased in dentate gyrus, and GABA(B)R2 mRNA was considerably reduced in CA3 region. In H10 and FS1 groups in which hyperthermia treatment was the same but no (H10 group) or only one seizure (FS(1) group) was induced, the decrease of GABA(B)R1a and GABA(B)R2 subunits and the reduced binding capability between GABA(B)R1a and GABA(B)R2 subunits were also detected but with less severity, and the time recovering from these abnormalities was shorter. We conclude that GABA(B)R1a and GABA(B)R2 subunits and the binding of the 2 subunits decrease in hippocampus for a relatively long period of time after recurrent FS in immature rats. These changes may result in long-lasting imbalance of excitation/inhibition function in hippocampus, and are derived from the consequences of recurrent febrile seizures.     

Amyloid precursor protein expression in the rat hippocampal dentate gyrus modulates during memory consolidation

Despite advances in our understanding of the basic biology of amyloid precursor protein (APP), the normal physiological function(s) of APP in learning and memory remains unclear. Here we show increased APP degradation in the hippocampus to be associated with the consolidation of a passive avoidance response. Neurone-specific APP695 expression became transiently reduced 2-4 h post-training through association with endosomal adaptin proteins and enhanced internalization. By contrast, internalization of glial-associated APP containing a Kunitz protease inhibitor-like domain (APP-KPI) was dependent on the low-density lipoprotein receptor-related protein (LRP). In addition, LRP expression and association with apolipoprotein E increased in the 2-4 h post-training period. The LRP antagonist receptor-associated protein prevented the APP-KPI internalization and LRP-apolipoprotein E association and this resulted in amnesia. Degradation of APP695 and APP-KPI did not appear to be related to alpha-secretase activity, as no learning-associated increase of secreted APP was observed in the CSF. Moreover, as internalization of APP isoforms was observed only in dentate gyrus, it probably relates to the learning-associated restructuring of the perforant path terminals. Memory-associated APP processing in both neuronal and glial compartments points to a role for glial unsheathing of synaptic connections, an event required for the synaptic restructuring that accompanies memory consolidation. These observations may have a direct relevance to understanding the pathophysiology of Alzheimer's disease as beta/gamma-secretase-derived beta-amyloid is formed following internalization of cell surface APP into the endosomal compartment.     

低频刺激后海马CA1区场兴奋性突触后电位与群体锋电位的变化

在大鼠海马脑片上使用双电极在CA1区进行细胞外记录 ,观察低频刺激 (LFS)诱发同突触长时程抑制 (LTD)时场兴奋性突触后电位 (fEPSP)的斜率 (S EPSP)和群体锋电位 (PS)的幅值 (A PS)的变化。给予 90 0脉冲 1HzLFS后 ,S EPSP和A PS降低的幅度分别是 35 4± 5 3%和 6 8 0± 7 2 % ;而给予 4 5 0脉冲 1HzLFS后 ,S EPSP和A PS分别降低 14 3± 2 3%和 36 8± 6 7%。上述两组中A PS的变化率均显著大于S EPSP (P <0 0 1) ,而 90 0脉冲数组中两个指标的变化率均大于 4 5 0脉冲数组 (P <0 0 5 )。高Mg2 + (4mmol/L)使突触的传递活动减弱 ,但不影响LTD的诱发 ,在高Mg2 + 介质中 ,LFS引起的A PS变化率仍显著大于S EPSP (P <0 0 1)。结果表明 ,由LFS诱发同突触LTD的水平不仅与LFS的脉冲数有关 ,还与评价指标的选择有关     

Age-related effects of the neuromodulator D-serine on neurotransmission and synaptic potentiation in the CA1 hippocampal area of the rat

The effects of the co-agonist of the N-methyl-D-aspartate receptor (NMDAr) D-serine on glutamatergic neurotransmission and synaptic potentiation were studied in the CA1 hippocampal field of young (3-5 months old) and aged (25-27 months old) Sprague-Dawley rats using ex vivo extracellular electrophysiological recording techniques. Exogenous d-serine depressed fast neurotransmission mediated by the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/kainate subtype of glutamate receptors in young but not in aged rats by acting on inhibitory glycinergic interneurons. In contrast, D-serine dose-dependently enhanced NMDAr-mediated synaptic responses in both groups of animals, but with a larger magnitude in aged rats, thus preventing the age-related decrease in NMDAr activation. D-serine also increased the magnitude of long-term potentiation in aged but not in young rats. Finally, D-serine levels were dramatically reduced in hippocampal tissues of aged rats. Taken together, these results indicate a weaker activation of the NMDAr glycine modulatory site by endogenous D-serine in aged animals, which accounts for a reduced NMDAr contribution to synaptic plasticity in ageing.     

维生素E对应激大鼠海马齿状回长时程增强的保护作用

目的：探讨维生素E对应激大鼠海马齿状回长时程增强的保护作用。方法：束缚应激条件下,通过补充维生素E（VE）,观察大鼠在应激过程中的行为效应。结果：接受应激大鼠在旷场实验中的穿行格数明显增加;长时程增强（LTP）诱发率降低,突触传递功能减弱;血浆糖皮质激素水平明显升高。而应激同时适量补充VE的大鼠未出现上述异常变化。结论：适当补充维生素E可减轻应激性海马突触传递功能障碍,提高机体应激适应能力。     

Chronic lithium enhances hippocampal long-term potentiation,but not neurogenesis,in the aged rat dentate gyrus

We investigated the hippocampal long-term potentiation (LTP), neurogenesis, and the activation of signaling molecules in the 20-month-old aged rats following chronic lithium treatment. Chronic lithium treatment produced a significant 79% increase in the numbers of BrdU(+) cells after treatment completion in the dentate gyrus (DG). Both LTP obtained from slices perfused with artificial cerebrospinal fluid (ACSF-LTP), and LTP recorded in the presence of bicuculline (bicuculline-LTP) were significantly greater in the lithium group than in the saline controls. Our results show that as with young rats, chronic lithium can substantially increase LTP and the number of BrdU(+) cells in the aged rats. However, neurogenesis, assessed by colocalization of NeuN and BrdU, was not detected in the aged rat DG subjected to chronic lithium treatment. Therefore, it is concluded that the increase in LTP and the number of BrdU(+) cells might not be associated with increases in neurogenesis in the granule cell layer of the DG. Lithium might has a beneficial effects through other signaling pathways in the aged brain.     

诱导成年大鼠海马CA1区长时程压抑的强直刺激型式

标准低频率连续刺激(1～2 Hz,15 min)能够诱导幼年大鼠(＜4周)海马CA1区同突触长时程压抑(long-term depression,LTD),而只有较高频率且持续时间较长的连续刺激才能诱导出成年动物该部位稳定的LTD.本研究采用成年大鼠海马脑片标本,电刺激Schaffer侧枝传入纤维,在CA1区锥体细胞层记录群体锋电位,选用两种新的刺激参数以观测不同刺激型式在诱导成年大鼠LTD中的作用.诱导LTD的刺激参数为(1)2 Hz,5串,串长60 s,串间隔60 s;(2)5 Hz,5串,串长24 s,串间隔96 s;(3)对照组参数2 Hz,300 s.结果显示,对照参数未能诱导出LTD;而两种频率不同但脉冲总数与刺激总时程相同的多串刺激,即参数(1)与参数(2),均在成年大鼠海马CA1区诱导产生了LTD.两种参数所诱导的LTD特征具有参数特异性,该特征主要表现为LTD诱导潜伏期和LTD的幅度参数(1)、(2)诱导的LTD的潜伏期分别为15～25 min和30～40 min;强直刺激后80 min时LTD的幅度分别为(57.5±2.8)%和(67.7±3.4)%.以上结果表明特定型式的低频率刺激能够诱导成年大鼠海马CA1区的LTD,提示LTD的诱导与刺激的组合型式相关,并且2 Hz较5 Hz的多串刺激在诱导LTD中更为有效.     

Contribution of Postsynaptic AMPA Receptor Channels to the Short- and Long-Term Synaptic Plasticity

The author briefly summarizes his own experimental data obtained earlier and reports evidence in favor of the contribution of postsynaptic AMPA receptor channels to the mechanisms underlying modifications of excitatory synaptic transmission in the CNS (in particular, in neocortical and hippocampal neuronal circuits).