大鼠海马神经元neurobasal无血清的原代培养方法

目的:建立纯度和活力较高的无血清原代培养海马神经元的方法。方法:新生SD大鼠海马,用neuro-basal培养基培养,免疫荧光鉴定神经元纯度,MTT法检测其活力。结果:神经元接种12~24 h后贴壁,并长出细小突起,3 d具有典型神经元形态特征,4 d突起形成稀疏的神经纤维网络,8 d后神经元5~10个聚集成团,突起密集,生长稳定,12 d后出现细胞碎片。Tubulin荧光染色显示清晰的神经元,突起绵长且相互交织,占细胞总数的66.7%;GFAP荧光染色的细胞数量少,突起短粗,占33.7%。培养1~5 d MTT代谢率逐渐上升,6~11 d处于平台期,11 d后下降。结论:neurobasal无血清培养获得的神经元纯度大于60%,6~11 d的细胞适于细胞学实验。     

Hippocampus＇s role in forming ＂task-related＂ associations： Flashing to the things you are looking for

Eichenbaum and colleagues observed that the same place did or did not activate the ＂goal-approach＂ cells in hippocampus depending on whether the place was the way for rats to approach specific goal. Parallel with this, the present neuroimage study revealed that, the same type of items could activate the hippocampus more when it was related to the task at hand than when it not. Participants were scanned by fMRI while they made judgments on the type of relationships contained in the word-pairs （e.g., Does the word pair, ＂furniture-table＂, contain a ＂category-exemplar＂ relationship？）. Event-related analysis revealed that the forming of ＂task-related＂ association activated hippocampus more than that of ＂task-unrelated＂, even if it was the same type of items, and, this hippocampal difference was not caused by the different judgment requirements, nor by the effects of ＂yes＂ response. Consistently, the post-judgment cued-recall test exhibited a better retrieval performance for ＂task-related＂ associations than for the same type but ＂task-unrelated＂ associations. Results also showed that, the semantic relatedness between the to-be-associated individual words （e.g., the related word pair ＂healthy-hospital＂ versus the unrelated word pair ＂price-way＂） was not enough to activate the hippocampus when it was ＂task-unrelated＂. Generally, we proposed that, through participating in forming of ＂task-related＂ associations and consolidating of episodic memory, hippocampus enabled the organism to keep the information that owned great survival values in mind for future usage.     

Making more synapses: a way to store information?

Although information may be stored in the brain as changes in the strength of existing synapses, formation of new synapses has long been thought of as an additional substrate for memory storage. The identification of subcellular structural changes following learning in mammals poses a serious ‘needle-in-the-haystack’ problem. In most attempts to demonstrate structural plasticity during learning, animals have been exposed for prolonged periods to complex environments, where they are confronted with a variety of sensory, motor and spatial challenges throughout the exposure period. These environments are thought to promote several forms of learning. Repeated exposure to such environments has been shown to increase the density of spines and dendritic complexity in relevant brain structures. The number of neurons has also been reported to increase in some areas. It is not clear, however, whether the new synapses emerging from these forms of plasticity mediate specific information storage, or whether they reflect a more general sophistication of the excited parts of the network.     

新型tacrine双联体对培养大鼠海马神经元NMDA受体作用位点的研究

目的：研究新型tacrine双联体bis（7）-tacrine对NMDA受体的作用位点.方法：大鼠海马神经元原代培养,全细胞膜片钳记录培养大鼠海马神经元上NMDA激活电流变化.结果：细胞外液pH值从8.1改变到6.7,在细胞外液中加入二硫苏糖醇（2 mmol/L）、精胺（10 mol/L）、镁离子（50～500 mol...     

运动训练大鼠长期停训后海马一氧化氮合成酶的表达变化

摘要：成酶((Nosynthetase,NOS)表达的影响。方法参照Bedford跑台训练方案．建立雄性sD大鼠有氧训练与疲劳训 练动物模型,停训28周。观察大鼠海马神经元NOS的表达变化。结果停训28周后,疲劳训练抑制了停训大鼠 海马NOS的表达。有氧训练促进了停训大鼠海马NOS的表达。结论早年长期有氧训练对改善大鼠海马组织细 胞机能．延缓其衰老,提高学习与记忆能力等方面有积极意义;而长期疲劳训练可能会对其包括学习与记忆能力等 方面的机能状态产生不利影响。     

大鼠脑组织腺苷含量的HPLC分析

用高效液相色谱（ＨＰＬＣ）配紫外检测器，分离测定大鼠脑组织中腺苷含量。经实验确定以甲醇（１０％～６２％）、磷酸缓冲液（９０％～３８％）为流动相梯度洗脱，样品液中腺苷含量在２ｍｇ／Ｌ～１０ｍｇ／Ｌ范围内线性关系良好。加入标准样品的平均回收率为（９６６±２０）％。对６ｍｇ／Ｌ样品１０次重复测定结果的标准偏差为０１４，变异系数为３１％。对大鼠脑组织样品测定结果发现：与３～６月龄成龄鼠比较，１８～２０月龄老龄大鼠大脑皮层、海马、纹状体中腺苷含量分别增加了６６７％、３７２％和２７３％，不同脑区腺苷含量也有明显差异。结果提示不同脑区腺苷含量的随龄增加可作为研究衰老的一项指标；而中枢神经系统中随龄增长腺苷的堆积使Ａｃｈ释放受到抑制可能是出现记忆衰退等常见老年性功能障碍的一个重要原因     

马桑内酯致痫大鼠海马IL-2免疫反应性的变化

目的:探求细胞因子中的白细胞介素2(Interleukin-2,IL-2)与癫痫发病之间的关系。方法:将Wistar大鼠分成三组,第一组侧脑室注入马桑内酯(Coriari Lactone,CL)2μL,第二组注入等量的生理盐水,第三组不做任何处理。然后运用免疫组织化学方法,对大鼠海马IL-2的免疫反应性进行分析;同时对实验中大鼠的行为及脑电图(eletroencepalograph,EEG)进行观察和记录。结果:第一组大鼠侧脑室注射CL过程中即诱发癫痫,且测到痫性脑电图,第二组、第三组无癫痫症状且未记录到痫性脑电图;第一组大鼠海马IL-2免疫反应性较第二组及第三组显著增强(P<0.01),表现在其海马CA_1、CA_2、CA_3区细胞数目增多,突起及其分支增多,着色明显加深;而第二、三组之间无明显差别(P>0.05)。结论:IL-2参与癫痫的发病过程,二者之间存在着一定的联系。     

中枢兴奋性传递的突触后电位小波熵分析研究

采用细胞内记录方法提取了离体大鼠海马脑片CA1区锥体神经元兴奋性突触后电位(EPSP)；应用小波熵研究了EPSP所包含的信息．在计算了EPSP的小波熵、幅度、上升和下降相速率等参数并对其进行相关矩阵分析后，发现EPSP小波熵与其幅度、上升和下降相速率等参数均具有较强的正相关关系，是EPSP最具代表性的一个特征参数．进而分析了大黄酸对中枢兴奋性传递的作用，发现神经元在灌流大黄酸前后小波熵参数值变化显著．研究表明，小波熵能较全面地表征EPSP信号特征，比传统参数更具代表性，并能较灵敏地反映神经元兴奋性改变，较好地反映神经元间的信息传递．     

Stimulation parameters determine role of GABAB receptors in long-term potentiation

Blockade of GABA_B receptors was reported to improve cognitive performance in mammals. The physiological basis of this effect is poorly understood. We investigated the effect of the GABA_B receptor antagonist CGP 35348 on long-term potentiation (LTP) in the CA1 area of the hippocampus in vitro and in vivo. In vitro the effect of CGP 35348 on LTP, induced either by two non-primed tetanic stimulations or by two primed bursts of stimuli, was investigated. In the presence of 1 mM CGP 35348 LTP was significantly facilitated following two non-primed tetanic trains, but was impaired following two primed burst stimulations. In vivo LTP was induced by applying non-primed trains of stimuli of increasing duration to the Schaffer collateral/commissural fibers. The potentiation of the population spike recorded in CA1 was significantly facilitated by CGP 35348 (100 mg/kg i.v.). In conclusion these findings demonstrate that the GABA_B antagonist CGP 35348 facilitates LTP in vitro and in vivo if induced by non-primed tetanic stimulation. In vitro, the mode of stimulation determines the effect of the GABA_B antagonist on LTP.     

Transitional function of DG to CA3 in the hippocampus

Using single cell channel model, the transmission features of CA3-DG network in the hippocampus are investigated. The influence of the stimulation on discharge pattern of pyramidal neurons is analyzed, which shows that it starts with period spiking discharges, followed by period-doubling bifurcation to chaos, and period 3 discharge evolving into chaos, and ultimately a period of bursting discharges. By the synaptic model, the CA3-DG network model is constructed, which analyzes the summation of postsynaptic currents in the network, the influence of postsynaptic current on discharge rhythm as well as the mechanism of bursting discharges. The strong capacity of spatiotemporal encoding in the network indicates the features of CA3 network during the information transmission process in the hippocampus. The modeling result with time delay of the synaptic transmission is in accordance with the experimental phenomena of action potential in the hippocampus.