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1.
本文研究人参总皂甙在海马齿状回颗粒细胞层诱发LTP效应和促进大鼠记忆保持能力时,对海马神经元核仁组织者区和苔藓纤维末梢出芽的影响。给人参总皂甙第7天可显著提高群峰电位(PS)幅度,缩短PS起始和峰潜伏期,并可显著提高大鼠记忆保持能力。此时人参总皂甙可使海马CA3区锥体细胞和齿状回颗粒细胞Ag-NOR数较盐水组大鼠的平均提高66.17±2.32%和72.07±0.93%(P<0.01);同时还可使大鼠的海马苔藓纤维末梢出芽级分平均较生理盐水组大鼠的平均堤高1-3倍(P<0.01)。提示人参总皂甙可提高神经元内rDNA的转录活性促进蛋白质合成,同时还可促进海马苔藓纤维末梢出芽以提高海马突触的传递功效。  相似文献   

2.
心房钠尿肽对大鼠主动脉弓压力感受器活动的影响   总被引:2,自引:0,他引:2  
在隔离灌流的大鼠主动脉弓-主动脉神经标本上,观察了心房肽Ⅲ(atriopeptinⅢ,APⅢ)对主动脉弓压力感受器活动的影响。主动脉弓内压保持13.3kPa条件下向灌流液中加入APⅢ(2.0μg/ml)后,主动脉神经传入放电较对照值增加64±27%(P<0.001);升降灌流压时,主动脉神经传入放电随之增减,饱和压(SP)由22.5±0.5降至21.3±0.5kPa(P<0.05),工作范围(OR)由12.1±0.4降至10.6±0.4kPa(P<0.05),阈压(TP)无明显变化;压力感受器机能曲线向左上方移位,曲线的最大积分值(PIV)由508±66%增至730±52%(P<0.05),曲线最大斜率(PS)由55.6±7.5增至93.2±6.8%·kPa-1(P<0.05);冲洗掉APⅢ后,主动脉神经传入放电基本恢复至对照水平.主动脉弓内压保持在13.3kPa条件下,向灌流液中加入硝普钠(NP,1.0μg/ml),主动脉神经传入放电虽有所减少,但无统计学意义(P>0.05);升降灌流压时,TP,SP,OR均无明显变化,对压力感受器机能曲线及PS也无显著影响,而PIV由667±78降至502±74%(P<  相似文献   

3.
目的 探讨将维生素A缺乏(VAD)胎鼠作为先天性心脏病动物模型的可行性。方法取11-19d不同胎龄正常及VAD胎鼠心脏经石蜡包埋、切片及 HE染色观察其发育情况。结果 1.实验组饲料含维生素A(VA)7μg/100g,经VAD饮食喂养后实验组大鼠血清VA水平明显低于对照组[(0.168±0.059)μmol/L Vs(2.18±0.23)μmol/L,t=32.88, P<0.001]。 2.大鼠死亡百分比:饲养于屏障系统的VAD大鼠死亡百分比较饲养于开放系统中的要低4.6倍(10% Vs 45.83%.x 2=16.64, P<0.001),对照组为0。 3.实验组大鼠受孕百分比及每只孕鼠产仔数均低于对照组[58.33% Vs 81.5%, x 2=4.37,P<0.05:(6.97±2.79) Vs(13 ±1.05),t=7.16, P<0.001]。 4.经切片观察11~15 d胎龄胎鼠实验组心脏出现明显发育延迟的占36.67%, 16~19 d胎龄胎鼠实验组心脏畸形占41.43%,血管异常占18.57%。结论VAD胎鼠可用来作为先天性心脏病动物模型,但需改进饲养环境以减少异常死亡。  相似文献   

4.
本文利用放射自显影方法结合神经毒对海马神经元的选择性损毁观察AVP(4-8)结合点在大鼠海马内的分布和定位;利用外源性AVP(4-8)对新生大鼠的处理,观察海马AVP(4-8)结合点的发育调节。在成年大鼠海马内,AVP(4-8)结合点集中分布在整个海马的锥体细胞层和齿回的颗粒细胞层。秋水仙碱处理后,齿回颗粒细胞层消失,齿回区的AVP(4-8)结合点也消失。红藻氨酸(Kainicacid)处理后海马CA3-CA4的锥体细胞层消失,该区的AVP(4-8)结合点也消失。新生大鼠海马锥体细胞层的AVP(4-8)结合点在出生后第6天开始出现,齿回颗粒细胞层的AVP(4-8)结合点在出生后第7天开始出现。然而,新生大鼠每天经外源性AVP(4-8)处理,海马锥体细胞层和齿回颗粒细胞层的结合点均在出生后第5天已变得十分稠密。本文就大鼠海马AVP(4-8)结合点的特异性分布和AVP(4-8)处理促进海马AVP(4-8)结合点的发育与成年后大鼠学习能力的提高的相互关系作了讨论。  相似文献   

5.
用外径4mm,内径2.50mm的硅胶管制成长25mm,管内填入DOCA100mg,管壁钻有10一14个直径约300μm微孔的药管,埋入雄性SD大鼠(140±9g)右下腹皮下,摘除一侧肾脏,术后喂1%盐水。埋管后3周即可形成高血压,埋管后8周大鼠的收缩压达23.3±0.37kPa。而DOCA皮下注射组大鼠(10mg/周)术后5周形成高血压,术后13周大鼠的收缩压达23.3±0.66kPa。两组升压曲线回归系数(1.295和0.692)之间的差异有极显著性意义(P<0.001)。对照鼠的收缩压一直保持在正常水平(16±0.16kPa)。与DOCA皮下注射法相比,皮下埋管法具有两个显著优点:(1)升压速率较快,升压幅度较大;(2)方法简便可靠,重复性好。  相似文献   

6.
电磁脉冲对大鼠学习和脑内神经递质的影响   总被引:9,自引:0,他引:9  
探讨电磁脉冲(EMP)对大鼠神经系统的效应。实验采用Wistar大鼠,EMP辐照后不同时间用Y-型迷宫测其学习能力,高效液相色谱法检测脑不同部位的神经递质含量。与假照射组(对照组)相比,照后三天内各测定组大鼠学习能力降低(P<0.05),其中照射后第1天组的海马内5-羟色胺(5-HT)和多巴酸(DOPAC)含量升高(P<0.05),下丘脑多巴胺(Dopamine)含量升高(P<0.05),肾上腺素(Adr)含量降低;照后2天组海马Adr含量降低(P<0.05),海马5-HT含量升高(P<0.05);照后3天组海马内Adr含量降低(P<0.05)。EMP能够改变大鼠不同脑区神经递质的含量,降低大鼠学习能力  相似文献   

7.
高钙引起的学习记忆障碍与突触界面结构参数的变化   总被引:2,自引:0,他引:2  
本研究选用1月龄小鼠,观察了海马内注射CaCl2造成高钙水平对小鼠学习和记忆行为的影响,并对海马CA3区进行突触超微结构定量分析。结果表明,与对照组相比:(1)CaCl2组小鼠一次性被动回避反应的步入潜伏期有缩短的趋势,说明该组小鼠记忆减弱;同时Y-迷宫分辨学习能力也显著下降(P〈0.01);(2)CaCl2组海马CA3区突触后致密物质极显著变薄(P〈0.001),而突触间隙宽度显著增大(P〈0.  相似文献   

8.
褐黑素对大鼠海马神经元谷氨酸所致毒性的拮抗作用   总被引:2,自引:0,他引:2  
Gao HX  Zhang LX 《生理学报》1999,51(4):430-434
在大鼠海马脑片上电刺激Schaffer侧支纤维,胞外记录CA1区锥体细胞层诱发群体锋电位,观察灌流谷氨酸和褪黑素对PS的影响。结果显示:5.0mmol/L浓度的Glu可使PS值下降至对照值的4.1%;ME(0.4、0.5和0.6μmol/L)一5.0mmol/L浓度的Glu可使PS值下降至对照值的14.7%、105.2%、24.3%;MEL、Glu,与赛庚啶混合给药,PS值下降至0。上述结果提示。  相似文献   

9.
目的和方法:采用核团微量注射、光化学分析等实验方法,观察大鼠脑内SOD和MDA在CCK-8调节癫痫发作中的变化。结果:①与下沉大鼠比较,遗传性听源性癫痫易感大鼠皮层、海马、下丘脑及垂体内SODF活性、MDA含量无显著差异(P>0.05);②大鼠癫痫发作后,上述区域内SOD活性明显降低(P<0.05),而MDA含量明显增加(P<0.05),若癫痫发作次数增加,该变化愈显著(P<0.01);③大鼠海马  相似文献   

10.
目的 应用体外细胞培养观察人参多糖对低温应激大鼠卵巢卵母细胞发育与颗粒细胞蛋白合成的影响,为研究人参多糖对低温应激大鼠卵巢功能的变化,提高机体耐寒能力提供科学实验解释.方法 培养Wistar大鼠卵巢卵母细胞与颗粒细胞,设37℃对照组,0、-15、-25与-35℃低温应激实验组,观察细胞计数.采用放免分析法测定3H-TdR与3H-Leu CPM值.结果 带卵泡卵母细胞低温应激实验组与对照组比较,生发泡破裂百分率57.14%/36.70%,人参多糖组68.97%/41.13%;带卵丘卵母细胞低温应激实验组与对照组比较,生发泡破裂百分率75.71%/41.14%,人参多糖组71.21%/39.28%,P<0.05.3H-TdR掺入量人参多糖为参照与对照组比较,人参多糖实验组为1279±191与913±212,低温人参多糖实验组均值为651±211与499±116.低温应激为参照与对照组比较低温实验组均值为499±116与913±212,低温人参多糖实验组均值为651±211与1279±191,P<0.05.3H-Leu掺入量人参多糖为参照与对照组比较,人参多糖实验组为889±153与617±119,低温人参多糖实验组均值为431±1144与300±119.低温应激为参照与对照组比较低温实验组均值为300±119与617±119,低温人参多糖实验组均值为431±144与889±153,P<0.05.结论 低温应激抑制卵母细胞发育与颗粒细胞蛋白合成,人参多糖能促进卵母细胞成熟,能使低温应激大鼠卵巢颗粒细胞蛋白合成增加,而对带卵丘的卵母细胞无作用.  相似文献   

11.
慢性复合应激增强大鼠空间学习和记忆能力   总被引:23,自引:0,他引:23  
Liu NB  Li H  Liu XQ  Sun CY  Cheng SR  Zhang MH  Liu SC  Wang WX 《生理学报》2004,56(5):615-619
本文观察了慢性复合应激对大鼠学习与记忆功能的影响。实验采用成年 Wistar 大鼠, 将其随机分成应激组和对照组。采用垂直旋转、睡眠剥夺、噪音刺激和夜间光照4 种应激原, 无规律地交替刺激动物 6 周, 每天6 h, 制作慢性复合应激动物模型。采用 Morris 水迷宫和 Y- 迷宫测试大鼠学习与记忆成绩,并用 Cresyl violet 染色法对大鼠海马结构进行神经细胞计数。结果显示,应激组动物慢性复合应激后, 在 Morris 水迷宫内寻找隐蔽平台所需的时间(潜伏期)比对照组的明显地短(P<0.05), 表明应激鼠的空间记忆能力明显强于对照鼠;在 Y- 迷宫内寻找安全区的正确率比对照组的明显地高(P<0.05), 表明应激鼠的明暗分辨学习能力明显强于对照鼠; 应激鼠慢性复合应激后, 其海马结构齿状回、CA3 和CA1 区神经细胞密度极明显地高于对照鼠(P<0.001)。这些结果提示, 慢性复合应激可增强大鼠空间记忆能力和明暗分辨学习能力。本文并对慢性复合应激模式增强大鼠学习和记忆能力的可能原因进行了讨论。  相似文献   

12.
Li Q  Bian S  Hong J  Kawase-Koga Y  Zhu E  Zheng Y  Yang L  Sun T 《PloS one》2011,6(10):e26000
The adult hippocampus consists of the dentate gyrus (DG) and the CA1, CA2 and CA3 regions and is essential for learning and memory functions. During embryonic development, hippocampal neurons are derived from hippocampal neuroepithelial cells and dentate granular progenitors. The molecular mechanisms that control hippocampal progenitor proliferation and differentiation are not well understood. Here we show that noncoding microRNAs (miRNAs) are essential for early hippocampal development in mice. Conditionally ablating the RNAase III enzyme Dicer at different embryonic time points utilizing three Cre mouse lines causes abnormal hippocampal morphology and affects the number of hippocampal progenitors due to altered proliferation and increased apoptosis. Lack of miRNAs at earlier stages causes early differentiation of hippocampal neurons, in particular in the CA1 and DG regions. Lack of miRNAs at a later stage specifically affects neuronal production in the CA3 region. Our results reveal a timing requirement of miRNAs for the formation of specific hippocampal regions, with the CA1 and DG developmentally hindered by an early loss of miRNAs and the CA3 region to a late loss of miRNAs. Collectively, our studies indicate the importance of the Dicer-mediated miRNA pathway in hippocampal development and functions.  相似文献   

13.
The hippocampal formation (the hippocampus and the dentate fascia) of the rabbit was studied by histochemical fluorescent method of Falk to determine localization of monoaminergic terminals containing biogenic amines: noradrenalin, dophamine and serotonin. It was shown that monoaminenergic terminals in the hippocampus were in two zones of afferent terminations: in the zone of ending of the perforating way (str. lacunosum-moleculare of fields CA1 and CA2; str. moleculare of the dentate fascia) and in the subgranular zone of the hilum where a part of septofimbrial way terminated on granular neurons of the dentate fascia, the main cellular elements of the hipocampus (pyramidal, granular and basket cells of the hippocampus) did not contain biogenic amines.  相似文献   

14.
Accumulating evidence points to an important role of intraneuronal Abeta as a trigger of the pathological cascade of events leading to neurodegeneration and eventually to Alzheimer's disease (AD) with its typical clinical symptoms, like memory impairment and change in personality. As a new concept, intraneuronal accumulation of Abeta instead of extracellular Abeta deposition has been introduced to be the disease-triggering event in AD. The present review compiles current knowledge on the amyloid precursor protein (APP)/PS1KI mouse model with early and massive intraneuronal Abeta42 accumulation: (1) The APP/PS1KI mouse model exhibits early robust brain and spinal cord axonal degeneration and hippocampal CA1 neuron loss. (2) At the same time-point, a dramatic, age-dependent reduced ability to perform working memory and motor tasks is observed. (3) The APP/PS1KI mice are smaller and show development of a thoracolumbar kyphosis, together with an incremental loss of body weight. (4) Onset of the observed behavioral alterations correlates well with robust axonal degeneration in brain and spinal cord and with abundant hippocampal CA1 neuron loss.  相似文献   

15.
Accumulating evidence points to an important role of intraneuronal Aβ as a trigger of the pathological cascade of events leading to neurodegeneration and eventually to Alzheimer's disease (AD) with its typical clinical symptoms, like memory impairment and change in personality. As a new concept, intraneuronal accumulation of Aβ instead of extracellular Aβ deposition has been introduced to be the disease-triggering event in AD. The present review compiles current knowledge on the amyloid precursor protein (APP)/PS1KI mouse model with early and massive intraneuronal Aβ42 accumulation: (1) The APP/PS1KI mouse model exhibits early robust brain and spinal cord axonal degeneration and hippocampal CA1 neuron loss. (2) At the same time-point, a dramatic, age-dependent reduced ability to perform working memory and motor tasks is observed. (3) The APP/PS1KI mice are smaller and show development of a thoracolumbar kyphosis, together with an incremental loss of body weight. (4) Onset of the observed behavioral alterations correlates well with robust axonal degeneration in brain and spinal cord and with abundant hippocampal CA1 neuron loss.  相似文献   

16.
The earliest stages of Alzheimer''s disease (AD) are characterized by deficits in memory and cognition indicating hippocampal pathology. While it is now recognized that synapse dysfunction precedes the hallmark pathological findings of AD, it is unclear if specific hippocampal synapses are particularly vulnerable. Since the mossy fiber (MF) synapse between dentate gyrus (DG) and CA3 regions underlies critical functions disrupted in AD, we utilized serial block-face electron microscopy (SBEM) to analyze MF microcircuitry in a mouse model of familial Alzheimer''s disease (FAD). FAD mutant MF terminal complexes were severely disrupted compared to control – they were smaller, contacted fewer postsynaptic spines and had greater numbers of presynaptic filopodial processes. Multi-headed CA3 dendritic spines in the FAD mutant condition were reduced in complexity and had significantly smaller sites of synaptic contact. Significantly, there was no change in the volume of classical dendritic spines at neighboring inputs to CA3 neurons suggesting input-specific defects in the early course of AD related pathology. These data indicate a specific vulnerability of the DG-CA3 network in AD pathogenesis and demonstrate the utility of SBEM to assess circuit specific alterations in mouse models of human disease.  相似文献   

17.
Fueta Y  Fukunaga K  Ishidao T  Hori H 《Life sciences》2002,72(4-5):521-529
Chronic inhalation of 1-bromopropane (1-BP), a substitute of ozone-depleting chlorofluorocarbons, has been suspected of having central neurotoxicity (Clinical Neurology and Neurosurgery 101 (1999) 199; Journal of Occupational Health 44 (2002) 1) for humans. In animal experiments, 1-BP inhalation (1500 ppm) caused hyperexcitability in the CA1 and the dentate gyrus (DG) [Journal of Occupational Health 42 (2000) 149, Journal of Occupational Health 44 (2002) 156]. We studied whether the hyperexcitability is associated with changes of Ca2+/calmodulin-dependent kinase II (CaMKII), mitogen-activated protein kinase (MAPK), and protein kinase C (PKC). Male Wistar rats were exposed to 1-BP for 6 hours in a day in an exposure chamber with a concentration of 700 ppm for 8 weeks. After the inhalation, paired-pulse ratios of field excitatory postsynaptic potentials and population spikes (PSs) were analyzed in the CA1 and DG of hippocampal slices. Control rats were then given fresh air in the inhalation chamber. Semiquantitative immunoblotting analyses of protein kinases using antibodies against active and conventional protein kinases were done using the whole hippocampus. A paired-pulse ratio of PS was increased at the 5 ms interpulse interval in the CA1 and at the 10-20 ms interpulse intervals in the DG. The amount of active MAPK and total amount of CaMKIIalpha and beta were significantly increased by 28, 29, and 46% compared to control, respectively, without any change in PKC activity. In contrast, the amount of active CaMKIIbeta was decreased to 78%. These results suggest that modifications of intracellular signaling cascades are associated with hyperexcitability that occurred in the hippocampal formation of rats exposed to the chronic inhalation of 1-BP.  相似文献   

18.
The developing brain is particularly sensitive to exposures to environmental contaminants. In contrast to the adult, the developing brain contains large numbers of dividing neuronal precursors, suggesting that they may be vulnerable targets. The postnatal day 7 (P7) rat hippocampus has populations of both mature neurons in the CA1–3 region as well as neural stem cells (NSC) in the dentate gyrus (DG) hilus, which actively produce new neurons that migrate to the granule cell layer (GCL). Using this well‐characterized NSC population, we examined the impact of low levels of methylmercury (MeHg) on proliferation, neurogenesis, and subsequent adolescent learning and memory behavior. Assessing a range of exposures, we found that a single subcutaneous injection of 0.6 µg/g MeHg in P7 rats induced caspase activation in proliferating NSC of the hilus and GCL. This acute NSC death had lasting impact on the DG at P21, reducing cell numbers in the hilus by 22% and the GCL by 27%, as well as reductions in neural precursor proliferation by 25%. In contrast, non‐proliferative CA1–3 pyramidal neuron cell number was unchanged. Furthermore, animals exposed to P7 MeHg exhibited an adolescent spatial memory deficit as assessed by Morris water maze. These results suggest that environmentally relevant levels of MeHg exposure may decrease NSC populations and, despite ongoing neurogenesis, the brain may not restore the hippocampal cell deficits, which may contribute to hippocampal‐dependent memory deficits during adolescence. © 2013 Wiley Periodicals, Inc. Develop Neurobiol 73: 936–949, 2013  相似文献   

19.
The marginal division (MrD) is a spindled-neurons consisted zone at the caudal border of the neostriatum in the mammalian brain and has been verified as contributing to associative learning and declarative memory in the rat and human with behavior and functional magnetic resonance imaging methods. It was proved to have functional connections with the limbic system. Whether the MrD has influence on the hippocampal long-term potentiation (LTP) was investigated in this study. LTP was induced from the dentate gyrus (DG) in the hippocampus by high-frequency stimulation (HFS) to the perforant path (PP). The amplitude of the population spike (PS) and the slope of the excitatory postsynaptic potential (EPSP) increased significantly to form LTP in the DG of the hippocampus after HFS of PP in normal and saline-injected control groups of rats. Lesions introduced in the MrD reduced significantly both the amplitude of PS and the slope of the EPSP following HFS of the PP. The results indicated that lesions in the MrD could attenuate LTP formation in the hippocampus. Our data suggest that the MrD might very possibly have excitatory functional influence on the hippocampus and therefore might influence the function of the hippocampus.  相似文献   

20.
为研究肉苁蓉苯乙醇苷对阿尔茨海默病模型小鼠海马β淀粉样蛋白表达的影响。实验选用6月龄APP/PS1双转基因AD模型小鼠60只,随机分为模型组、多奈哌齐组(0.65mg/kg)、肉苁蓉苯乙醇总苷剂量组(250,125,62.5mg/kg)、肉苁蓉毛蕊花糖苷组(125mg/kg),正常组为同窝非转基因小鼠10只,分别给予药物和蒸馏水灌胃3个月,于9月龄时通过Morris水迷宫法检测行为学改变,采用HE染色法观察小鼠脑部海马病变,采用免疫组化法和Western-blot法考察海马Aβ1-42和Aβ1-40蛋白表达。实验结果发现肉苁蓉苯乙醇苷明显改善小鼠学习与记忆能力和脑部海马神经元的损伤,减少Aβ1-42、Aβ1-40阳性细胞数,并下调蛋白表达。肉苁蓉苯乙醇苷通过下调小鼠海马脑区Aβ1-42、Aβ1-40蛋白表达,从而影响Aβ级联反应以保护神经元,发挥拮抗AD作用。本研究明确了苯乙醇苷是肉苁蓉发挥抗AD活性的主要药效物质基础,为后续将其开发为抗AD新药提供了理论支撑。  相似文献   

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