行为学训练对海马损伤梗死大鼠齿状回区BrdU和Nestin表达的影响

目的 探讨行为学训练对海马损伤梗死大鼠齿状回区神经干细胞增殖的影响。方法 采用光化学法制成单侧海马损伤梗死模型大鼠72只,随机分为训练组（n=36）和自由活动组（n=36）,每个组设1、7、14、21、28及35d 6个亚组。另设正常对照组36只,与模型组对应分为1、7、14、21、28及35d 6个亚组。训练组大鼠于造模1d后给予水迷宫训练,自由活动组大鼠自由活动,不予水迷宫训练。免疫荧光双标记法观察各不同时间点大鼠海马齿状回区溴脱氧尿嘧啶核苷（Bromodeoxyuridine,BrdU）与巢蛋白（Nestin）的双标记表达情况。结果 正常对照组大鼠海马齿状回区有少量BrdU/Nestin双标记阳性细胞,训练组及自由活动组大鼠在7、14、21及28d海马损伤梗死侧齿状回区BrdU/Nestin双标记阳性细胞数量均有显著增多（P <0.01）;训练组大鼠7、14、21、28d时海马损伤梗死侧齿状回区的BrdU/Nestin双标记阳性细胞数量显著高于自由活动组（P <0.01）;至35d时,训练组及自由活动组大鼠海马损伤梗死侧齿状回区BrdU/Nestin双标记阳性细胞数量与正常对照组无明显差异（P >0.05）。结论 行为学训练能显著增强海马损伤梗死大鼠齿状回区神经干细胞的增殖,促进神经功能恢复。     

康复训练对血管性痴呆大鼠认知功能障碍的影响及其分子机制

目的探讨康复训练对血管性痴呆大鼠空间学习记忆能力的改善作用,并从分子学角度探讨其机制。方法选择Wistar雄性大鼠25只,随机分为正常对照组(5只)、血管性痴呆组(10只)和康复训练组(10只)。采用双侧颈总动脉阻断法制作血管性痴呆大鼠模型,康复训练组大鼠于手术后2d开始进行康复训练;用Westernblotting方法测定大鼠海马组织中N-甲基-D-天冬氨酸受体1含量,用长时程增强及Morris水迷宫试验评价大鼠空间学习记忆能力。结果Morris水迷宫试验显示,血管性痴呆组大鼠水迷宫隐匿平台逃避潜伏期明显延长,经康复训练后学习记忆能力有所改善,但与正常对照组相比差异仍有统计学意义(P<0.05)。发生血管性痴呆后,大鼠海马组织中N-甲基-D-天冬氨酸受体1含量明显降低,康复训练使其含量较训练前明显升高,但仍未能达到正常对照组水平(P<0.05);血管性痴呆大鼠的长时程增强诱导功能亦明显受到抑制,康复训练后虽明显改善但未恢复至正常水平(P<0.05)。结论康复训练可提高大鼠空间学习记忆能力,促进长时程增强的形成,其分子机制可能与海马组织中N-甲基-D-天冬氨酸受体1表达水平的增高有关。     

血管性痴呆大鼠学习记忆障碍及脑组织生长抑素的变化

目的探讨生长抑素（SS）参与血管性痴呆（VD）大鼠学习记忆障碍的作用机制。方法采用双侧颈总动脉结扎法制备慢性前脑缺血动物模型，随机分为假手术组（S）、模型组（M）。造模2月后进行水迷宫试验，观察2组大鼠空间学习记忆能力的差异，应用免疫组化方法检测造模2月后VD大鼠海马及颞叶皮层生长抑素表达变化。结果与假手术组比较，大鼠水迷宫学习记忆能力在造模2月后差异有显著性意义（P〈0．05），大鼠海马及颞叶皮层SS表达在造模2月后降低（P〈0．05）。结论脑组织SS表达降低，导致血管性痴呆大鼠学习记忆障碍。     

学习记忆训练对全脑缺血大鼠认知能力的影响

目的探讨学习记忆训练对全脑缺血大鼠空间学习记忆能力的影响及检测脑源性神经营养因子的变化。方法选用健康雄性SD大鼠90只随机分为假手术组、对照组和训练组,采用改良Pulsinelli’s 4血管闭塞法(4-VO)制作全脑缺血大鼠模型,术后1周以Y型电迷宫训练大鼠,分别在训练7d、14d、21d后应用Y型电迷宫检测比较3组大鼠的空间学习记忆能力的差异;HE染色观察CA1区神经元变化;免疫组化检测脑源性神经营养因子的表达。结果训练21d后,对照组与假手术组和训练组比较,Y型电迷宫全天总反应时间和潜伏期明显延长(P<0.05),错误反应次数明显增多(P<0.05)。对照组CA1区脑源性神经营养因子的光密度值明显低于训练组(P<0.05)。结论学习记忆训练可以改善全脑缺血大鼠的空间学习记忆能力,提示应用学习记忆训练方法可以改善全脑缺血损伤后引起的学习记忆障碍。     

一氧化氮合酶抑制剂对大鼠学习记忆能力的影响及尼莫地平的作用研究

目的：研究一氧化氮合酶抑制剂对大鼠学习记忆障碍的影响，和其海马一氧化氮(NO)变化及尼莫地平的作用。方法：大鼠双侧海马注入N-ω-硝基—L精氨酸(LNA)建立学习记忆障碍模型，注完L-NA后再给大鼠腹腔内注射尼莫地平，用Y型电迷宫进行学习记忆能力测试。取大鼠海马部位组织检测N0含量。结果：模型组大鼠的学习记忆能力明显低于对照组大鼠，干预组大鼠的学习记忆能力与模型组无差异；模型组大鼠的海马N0含量明显低于对照组，干预组大鼠海马N0含量与模型组无显著差异。结论：双侧海马注入L-NA可使大鼠出现学习记忆障碍，海马N0浓度降低。尼莫地平对L-NA所致的学习记忆障碍无治疗作用。     

行为学训练对低剂量X线照射后SD大鼠认知能力的改善作用研究

目的 探讨行为学训练对低剂量X线照射后幼年SD大鼠学习记忆的影响及其相关机制. 方法 出生后35d的SD大鼠按抽签法随机分为训练组、照射组及对照组,每组各16只.照射组、训练组每天均接受1次低剂量[以临床中婴幼儿(0～6岁)所采用剂量为基准]X线照射,共7d.对照组接受假照射.通过Morris水迷宫训练其学习记忆能力,7.0T MR检测3组大鼠海马区N-乙酰-天门冬氨酸/肌酸(NAA/Cr)比值.荧光免疫组化法和Western blotting检测各组大鼠海马区细胞色素C氧化酶亚基Ⅳ(COXⅣ)蛋白表达的变化.HE染色观察海马CA1区神经元形态,透射电镜观察神经元线粒体形态. 结果 (1)照射组NAA/Cr值(1.611±0.013)较对照组(1.873±0.032)明显降低,训练组NAA/Cr值(1.870±0.018)较照射组明显升高,差异均有统计学意义(P＜0.05).(2)定位航行实验中照射组大鼠第1～4天逃避潜伏期均长于对照组大鼠,差异有统计学意义(P＜0.05);训练组大鼠第1～4天逃避潜伏期与对照组大鼠无明显区别,差异无统计学意义(P＞0.05).空间探索实验中,照射组大鼠穿越原站台次数、原站台象限停留时间均明显少于对照组,差异有统计学意义(P＜0.05);训练组大鼠穿越原站台次数、原站台象限停留时间与对照组大鼠无明显区别,差异无统计学意义(P＞0.05).(3)荧光免疫组化结果显示照射组大鼠海马CA1区COXⅣ蛋白表达减少,训练组COXⅣ表达增加.Western blotting结果显示照射组大鼠海马CA1区COXⅣ蛋白表达(0.298±0.049)较对照组(0.998±0.056)明显减少,差异有统计学意义(P＜0.05);训练组COXⅣ表达(0.987±0.053)接近训练组,差异无统计学意义(P＞0.05).(4)照射组大鼠可见核固缩及较多受损的线粒体,训练组大鼠仅见少量受损线粒体. 结论 行为学训练可能通过增加COXⅣ蛋白表达,改善线粒体形态及功能来恢复低剂量X线照射后幼年SD大鼠受损的学习记忆能力.     

康复训练联合促红细胞生成素对脑出血大鼠神经 修复及海马胶质原纤维酸性蛋白表达的影响

目的 康复训练联合促红细胞生成素（EPO）对脑出血大鼠神经修复及海马组织胶质原纤 维酸性蛋白（GFAP）表达的影响。方法 健康雄性SD 大鼠30 只随机分成3 组：模型组、EPO 组和训练组， 每组各10 只大鼠。3 组均建立脑出血模型，EPO 组与训练组在造模成功24 h 后均腹腔注射EPO，训练组 大鼠给予康复训练，模型组注射与EPO 组及训练组所注射EPO等量的生理盐水。观察与检测大鼠神经 修复及海马GFAP表达情况。结果 所有大鼠均造模成功，EPO 组与训练组造模后7 d、14 d 和28 d 的 Tarlov 评分高于模型组（P＜ 0.05），训练组也显著高于EPO 组（P ＜ 0.05）。造模后28 d，EPO 组与训练组 的脑含水量、血清IL-6 和TNF-α 值、海马组织GFAP蛋白相对表达水平显著低于模型组（P＜ 0.05），训练 组也低于EPO 组（P ＜ 0.05）。结论 康复训练联合EPO在脑出血大鼠中的应用能抑制海马GFAP表达 与血清炎性因子的释放，减轻脑水肿，从而促进神经功能恢复正常。     

灵芝多糖对模拟AD学习记忆障碍大鼠海马白细胞介素-6表达的影响

目的 研究灵芝多糖对模拟AD学习记忆障碍大鼠脑组织白细胞介素-6表达（IL-6）的影响。方法 采用双侧海马内一次性注射β-淀粉样多肽25～35片段（Aβ25～35）制作模拟AD学习记忆障碍大鼠模型，造模24h后治疗组腹腔注射灵芝多糖注射液，其余各组分别注射等量的生理盐水，1次/d，疗程7d，并于第8d开始进行Morris水迷宫实验观察其学习记忆能力，行为学检测后再通过免疫组化SABC法检测各组大鼠海马IL-6表达水平。结果 模型组大鼠较对照组学习记忆能力降低，海马IL-6表达明显增强；治疗组大鼠较模型组学习记忆能力显著提高，海马IL-6表达显著下调。结论 灵芝多糖可提高Aβ25-35诱导的模拟AD学习记忆障碍大鼠的学习记忆能力，抑制海马IL-6表达。     

γ-氨基丁酸对慢性脑缺血致血管性痴呆大鼠学习记忆能力的影响

目的观察γ-氨基丁酸（GABA）对慢性脑缺血致血管性痴呆（VD）大鼠学习记忆能力及海马CA1区神经元形态学的影响。方法将SD大鼠随机分为假手术组、模型组、GABA组,采用双侧颈总动脉永久性结扎法建立VD模型。GABA组术后腹腔注射GABA0.5g.kg-1.d-1,连续注射60d;用Morris水迷宫实验检测大鼠空间学习记忆能力;Nissl染色观察大鼠海马CA1区神经元形态学变化。结果 GABA能明显改善VD大鼠学习记忆能力,也能减轻海马CA1区神经元损伤。结论 GABA能改善慢性脑缺血致VD大鼠的学习记忆能力,减轻海马神经元损伤可能是其机制之一。     

血管性痴呆大鼠认知功能及nNOS的表达

目的 探讨血管性痴呆(VD)大鼠认知功能、海马神经元结构及nNOS的表达.方法 采用双侧颈总动脉结扎法制备慢性前脑缺血动物模型,40只老龄大鼠随机分为假手术组(S)、模型组(M).应用水迷宫、透射电镜及免疫组化方法对2组大鼠学习记忆、神经元结构、nNOS表达进行观察.结果 与假手术组比较,大鼠水迷宫学习记忆能力在造模2个月后差异有统计学意义(P＜0.05),大鼠海马神经元在造模后变性水肿明显,大鼠海马及颞叶皮层nNOS在造模2个月后表达增加 (P＜0.05).结论 海马及颞叶皮层nNOS表达增加,神经元变性,可能导致血管性痴呆大鼠学习记忆障碍.     

Distribution of polysialylated neural cell adhesion molecule in rat septal nuclei and septohippocampal pathway: transient increase of polysialylated interneurons in the subtriangular septal zone during memory consolidation

During memory consolidation neuroplastic events in the mediotemporal corticohippocampal pathway are accompanied by transient increases in the frequency of neurons expressing polysialylated neural cell adhesion molecule (NCAM PSA), a posttranslational modification associated with morphofunctional change. As a bidirectional pathway between the hippocampus and the septal nuclei also influences memory processing, we have determined the distribution of NCAM PSA within this system before and after learning in the adult Wistar rat. The most intense NCAM PSA immunoreactivity was observed in the medial and triangular septal nuclei, regions that regulate hippocampal theta rhythm during memory consolidation. Within the fimbria, NCAM PSA was expressed only in a subpopulation of fibres, most likely cholinergic projections from the medial septum to the hippocampus. Grey level analysis or direct cell counting revealed no learning-specific change in NCAM PSA expression in these septal subregions after avoidance conditioning or spatial training. A population of discrete polysialylated neurons in the subtriangular septal zone, however, exhibited a transient twofold frequency increase at 12 hr after training in either task. Immunohistochemical analysis revealed these cells to be gamma-aminobutyric acid (GABAergic) interneurons co-expressing vasoactive intestinal peptide. The unique location of these interneurons is proposed to provide a natural plexus by which bidirectional communication between the septum and hippocampus may be modified during memory consolidation.     

Hippocampal up-regulation of NCAM expression and polysialylation plays a key role on spatial memory

Memory formation has been associated with structural and functional modifications of synapses. Cell adhesion molecules are prominent modulators of synaptic plasticity. Here, we investigated the involvement of the cell adhesion molecules, NCAM, its polysialylated state (PSA-NCAM) and L1 in spatial learning-induced synaptic remodeling and memory storage. A differential regulation of these adhesion molecules was found in the hippocampus of rats submitted to one training session in the spatial, but not cued, version of the Morris water maze. Twenty-four hours after training, synaptic expression of NCAM and PSA-NCAM was increased, whereas L1 appeared markedly decreased. The regulation of these molecules was spatial learning-specific, except for L1 reduction, which could be attributed to swimming under stressful conditions rather than to learning. Subsequent psychopharmacological experiments were performed to address the functional role of NCAM and PSA-NCAM in the formation of spatial memories. Rats received an intracerebroventricular injection of either a synthetic peptide (C3d) aimed to interfere with NCAM function, or endoneuraminidase, an enzyme that cleaves polysialic acid from NCAM. Both treatments affected acquisition of spatial information and lead to impaired spatial memory abilities, supporting a critical role of the observed learning-induced up-regulation of synaptic NCAM expression and polysialylation on spatial learning and memory. Therefore, our findings highlight NCAM as a learning-modulated molecule critically involved in the hippocampal remodeling processes underlying spatial memory formation.     

托吡酯对癫痫大鼠认知功能及海马组织中NCAM的mRNA表达影响

目的研究托吡酯（TPM）对癫痫大鼠认知功能的影响以及使用TPM后大鼠海马组织中神经细胞粘附分子（NCAM）的mRNA表达变化。方法将大鼠随机分成生理盐水（NS）组、癫痫（EP）组、癫痫＋托吡酯治疗1周（TPM1周）组和癫痫＋托吡酯治疗4周（TPM4周）组,建立匹罗卡品诱导癫痫大鼠模型和TPM干预模型,观察大鼠的行为学改变,通过Morris水迷宫实验测试大鼠的学习记忆能力,并通过Real—TimePCR检测大鼠海马组织中NCAM的mRNA表达水平。结果EP组大鼠的逃避潜伏期大于NS组,原平台象限游泳时间百分比小于NS组,海马NCAM的mRNA表达水平高于NS组（P〈0．01）;TPM1周组和TPM4周组大鼠的逃避潜伏期大于EP组,原平台象限游泳时间百分比小于EP组,海马NCAM的mRNA表达水平低于EP组（P〈0.01）;TPM4周组大鼠的逃避潜伏期大于TPM1周组,原平台象限游泳时间百分比小于TPM1周组,海马NCAM的mRNA表达水平低于TPMI周组（P〈0.05）。结论大鼠产生癫痫持续状态后认知功能明显下降,海马NCAM的mRNA表达上调;使用大剂量TPM短期治疗后其认知功能进一步下降,海马NCAM的mRNA表达受抑,且下降与受抑程度与TPM的持续使用时间有关。     

托吡酯对戊四氮点燃慢性癫(癎)大鼠海马神经细胞黏附分子的影响

目的:探讨神经元活化在癫发生、发展中的作用及托吡酯对其的影响。方法:采用戊四氮制备慢性癫模型,利用托吡酯干扰,选取不同时间点,观察大鼠行为学变化及神经细胞黏附分子在海马回的表达(免疫组织化学染色)。结果:托吡酯组点燃率在27d明显低于模型组;模型组及托吡酯组神经细胞黏附分子表达增加,并随时间延长明显;而不同时间点该表达的增加程度,托吡酯组均低于模型组。结论:神经细胞黏附分子表达的增加,说明出现了神经元活化及脑可塑性变化,而托吡酯明显地抑制了该表达的增加。     

Olfactory learning-related NCAM expression is state, time, and location specific and is correlated with individual learning capabilities

The notion that long-term synaptic plasticity is generated by activity-induced molecular modifications is widely accepted. It is well established that neural cell adhesion molecule (NCAM) is one of the prominent modulators of synaptic plasticity. NCAM can be polysialylated (PSA-NCAM), a reaction that provides it with anti-adhesion properties. In this study we have focused on NCAM and on its polysialylated state, and their relation to learning of an olfactory discrimination task, which depends on both the piriform (olfactory) cortex and hippocampus. We trained rats to distinguish between pairs of odors until rule learning was achieved, a process that normally lasts 6-8 days. At four time points, during training and after training completion, synaptic NCAM and PSA-NCAM expression were assessed in the piriform cortex and hippocampus. We report that NCAM modulation is specific to PSA-NCAM, which is upregulated in the hippocampus one day after training completion. We also report a correlation between the performance of individual rats in an early training stage and their NCAM expression, both in the piriform cortex and hippocampus. Since individual early performance in our odor discrimination task is correlated with the performance throughout the training period, we conclude that early NCAM expression is associated with odor learning capability. We therefore suggest that early synaptic NCAM expression may be one of the factors determining the capability of rats to learn.     

Causal evidence for the involvement of the neural cell adhesion molecule,NCAM, in chronic stress‐induced cognitive impairments

In rodents, chronic stress induces long‐lasting structural and functional alterations in the hippocampus, as well as learning and memory impairments. The neural cell adhesion molecule (NCAM) was previously hypothesized to be a key molecule in mediating the effects of stress due to its role in neuronal remodeling and since chronic stress diminishes hippocampal NCAM expression in rats. However, since most of the evidence for these effects is correlative or circumstantial, we tested the performance of conditional NCAM‐deficient mice in the water maze task to obtain causal evidence for the role of NCAM. We first validated that exposure to chronic unpredictable stress decreased hippocampal NCAM expression in C57BL/6 wild‐type mice, inducing deficits in reversal learning and mild deficits in spatial learning. Similar deficits in water maze performance were found in conditional NCAM‐deficient mice that could not be attributed to increased anxiety or enhanced corticosterone responses. Importantly, the performance of both the conditional NCAM‐deficient mice and chronically stressed wild‐type mice in the water maze was improved by post‐training injection of the NCAM mimetic peptide, FGLs. Thus, these findings support the functional involvement of NCAM in chronic stress‐induced alterations and highlight this molecule as a potential target to treat stress‐related cognitive disturbances. © 2009 Wiley‐Liss, Inc.     

Regulation of hippocampal cell adhesion molecules NCAM and L1 by contextual fear conditioning is dependent upon time and stressor intensity

Cell adhesion molecules (CAMs) of the immunoglobulin superfamily, NCAM and L1, as well as the post-translational addition of alpha-2, 8-linked polysialic acid (PSA) homopolymers to NCAM (PSA-NCAM), have been implicated in the neural mechanisms underlying memory formation. Given that the degree of stress elicited by the training situation is one of the key factors that influence consolidation processes, this study questioned whether training rats under different stressor intensities (0.2, 0.4, or 1 mA shock intensity) in a contextual fear conditioning task might regulate subsequent expression of NCAM, PSA-NCAM and L1 in the hippocampus, as evaluated immediately after testing rats for conditioning at 12 and 24 h after training. Behavioural inhibition (evaluated as a 'freezing' index) at testing and post-testing plasma corticosterone levels were also assessed. The results showed that 12 h post-training, conditioned animals displayed reduced NCAM, but increased L1, expression. At this time point, the group trained at the highest shock intensity (1 mA) also presented decreased PSA-NCAM expression. Analyses performed 24 h post-training indicated that the 1 mA group exhibited increased NCAM and L1 expression, but decreased expression of PSA-NCAM levels. In addition, L1 values that presented a shock intensity-dependent U-shaped pattern were also increased in the group trained at the lowest shock condition (0.2 mA) and remained unchanged in the intermediate shock condition (0.4 mA). Freezing and corticosterone values at both testing times were positively related with shock intensity experienced at training. Therefore, our results show a complex regulation of CAMs of the immunoglobulin superfamily in the hippocampus that depends upon stressor intensity and time factors. In addition, the pattern of CAMs expression found in the 1 mA group (which is the one that shows higher post-training corticosterone levels and develops the stronger and longer-lasting levels of fear conditioning) supports the view that, after a first phase of synaptic de-adherence during consolidation, NCAM and L1 might participate in the stabilization of selected synapses underlying the establishment of long-term memory for contextual fear conditioning, and suggests that glucocorticoids might play a role in the observed regulation of CAMs.     

步长脑心通对血管性痴呆大鼠学习记忆及血管内皮细胞生长因子作用的影响

目的观察步长脑心通对VD模型学习记忆能力、海马区血管内皮细胞生长因子(VEGF)的影响。方法将50只大鼠随机分为正常组、假手术组、模型组、西药(喜德镇)组及步长脑心通组,建立实验动物模型。分别于制模后、30d后进行跳台实验进行大鼠行为学检测;应用免疫组化法分析大鼠海马部位VEGF分布情况。结果步长脑心通组学习记忆成绩优于模型组,其大鼠海马组织内VEGF明显增加。结论步长脑心通能改善模型大鼠的学习记忆能力,能明显增强VD模型大鼠海马组织VEGF表达,从而减轻VD模型大鼠的缺血性损伤。     

The effects of antiepileptic drugs on spatial learning and hippocampal protein kinase C gamma in immature rats

This study was conducted to determine if alterations in hippocampal protein kinase C (PKC) gamma is one of the cellular mechanisms by which conventional antiepileptic drugs affect learning and memory. Wistar Rats (21-day-old) were divided into five groups: (1) control (no training and drugs); (2) training group (no drugs); (3) phenobarbital (PB) group; (4) carbamazepine (CBZ) group; and (5) valproate (VPA) group. A hippocampus dependent learning task (spatial changing learning) was used in the latter four groups lasting a total of 10 days. Correct responding rate of training group was significantly higher (P < 0.05) than in the PB, CBZ and VPA group. The PKC gamma staining intensity in hippocampal CA1-2 region of training group was significant greater than that of the control and PB group. There was no difference in staining intensities between the CBZ, VPA group or training group. The amount of PKC gamma located in plasma membrane of hippocampal neurons was significantly higher in the training group (P < 0.05) than the control, PB and VPA groups. No differences were found between the training and CBZ group. Lastly, the amount of PKC gamma in cytosol of hippocampus did not significantly differ between any of the five groups. These results indicate that the three antiepileptic drugs used in this study all disturbed the spatial learning of immature rats. Spatial learning was concomitant with activation of PKC gamma in hippocampal neurons. PB and VPA likely adversely affect learning and memory by interfering with PKC gamma activation, whereas CBZ may act by a different mechanism, possibly in the post-translocation process or by a PKC gamma independent pathway.