不同底物对Sombati癫(癎)细胞模型整合素α2表达的影响

目的:探讨不同底物对经体外培养的Sombati癫(癎)细胞模型海马神经元整合素α2表达水平的影响及意义.方法:以层黏连蛋白和多聚L-赖氨酸作为底物于体外培养新生小鼠海马神经元,至第7天时行神经元纯度鉴定;无镁细胞外液继续培养3h后制备Sombati癫(癎)细胞模型,逆转录-聚合酶链反应检测小同处理组海马神经元整合素α2...     

不同底物对Sombati癫癎细胞模型整合素α2表达的影响

目的探讨不同底物对经体外培养的Sombati癫癎细胞模型海马神经元整合素α2表达水平的影响及意义。方法以层黏连蛋白和多聚L-赖氨酸作为底物于体外培养新生小鼠海马神经元,至第7天时行神经元纯度鉴定;无镁细胞外液继续培养3h后制备Sombati癫癎细胞模型,逆转录-聚合酶链反应检测不同处理组海马神经元整合素α2mRNA相对表达变化。结果模型制备前,经体外培养至第5天的层黏连蛋白组神经元胞体增大、饱满,突起连接紧密,神经网络形成,多聚L-赖氨酸组则体外培养至第7天时方出现上述表现;模型制备后24h,不同处理组神经元均可见迁移现象和神经网络“网格”样改变,但不同处理组神经元形态无明显差异。以整合素α2与β肌动蛋白光密度值之比值代表整合素α2mRNA相对表达量,多聚L．赖氨酸组、层黏连蛋白组和多聚L-赖氨酸＋层黏连蛋白组分别为0．25±0．03、0．37±0．05和0．48±0．09,后两组整合素α2mRNA表达水平高于多聚L-赖氨酸组,且差异有统计学意义（P=0．005,0．000）。结论与多聚L-赖氨酸组相比,层黏连蛋白对经体外培养的原代神经元贴壁及轴突连接具有较强的促进作用。添加外源性层黏连蛋白可诱导Sombati癫癎细胞模型海马神经元整合素α-mRNA表达上调。     

氟桂利嗪对青霉素致痈效应和海马神经元单位放电的影响

目的：探讨Ca^2＋拮抗剂氟桂利嗪对青霉素致效应和海马神经元单位放电的影响.方法：Wistar大鼠随机分成3组.正常对照组;癫癎模型组：用青霉素钠按6 000 000 U·kg^-1腹腔注射;癫癎预处理组：造模前用盐酸氟桂利嗪 20 mg·kg^-1每隔12 h灌胃,共2次,于第2次给药2 h后制作模型.观察癫癎发作并记录海马神经元单位放电.结果： ①正常对照组大鼠共记录到24个单位海马神经元放电;②癫癎模型组共记录到78个单位海马神经元放电,癫癎发作程度强,发作频率高;③癫癎预处理组共记录到47个单位海马神经元放电,癫癎发作程度减轻,发作频率减少.结论：氟桂利嗪可抑制青霉素致效应,减少海马神经元的单位放电.     

海马神经元癫癎样放电模型中神经元凋亡的研究

目的通过检测体外海马神经元癫癎样放电后的细胞凋亡,旨在探讨颞叶癫癎病人海马神经元丢失的机制.方法首先制备Sombati神经元癫癎样放电模型,然后采用Tunel标记、荧光染色以及流式细胞技术对模型中的凋亡神经元作了定性和定量检祆测.结果发现神经元癫癎样放电后出现细胞凋亡,且随着放电时间的延长,凋亡细胞增加.结论反复癫癎样放电导致神经元凋亡,其发生可能与癫癎样放电的兴奋性毒性有关.     

托吡酯对戊四氮致癫癎大鼠海马AQP4表达水平的影响

目的探讨托吡酯对戊四氮致癫癎大鼠海马AQP4表达水平的影响。方法将30只Wistar大鼠随机分为戊四氮致癫癎组、托吡酯干预组和正常对照组，每组各10只；癫癎模型点燃后在不同时相点灌注取材，通过HE染色观察大鼠海马神经元的变化，并应用免疫组化法检测大鼠海马AQP4表达水平。结果HE染色显示托吡酯干预组神经元变性和坏死较戊四氮致癫癎组明显减轻；免疫组化显示戊四氮致癫癎组在致癫癎后12hAQP4的表达显著增强，致癫癎后24h达高峰，托吡酯干预组在致癫癎后12h～36h各时相点AQP4表达水平均分别低于戊四氮致癫癎组相应时间点（P〈0．05）。结论托吡酯通过下调大鼠海马AQP4的表达可能参与了对大鼠海马神经元的保护过程。     

匹罗卡品致癎大鼠海马γ-氨基丁酸能中间神经元生长抑素和微清蛋白mRNA表达研究

目的观察匹罗卡品致癎大鼠海马γ-氨基丁酸能中间神经元生长抑素（SS）mRNA和微清蛋白（PV）mRNA表达水平变化,拟从基因水平探讨其表达阳性叮一氨基丁酸能中间神经元在颞叶癫癎发生发展中的作用。方法建立匹罗卡品致癎大鼠模型,采用原位杂交法检测各观察时间点海马SSmRNA和PVmRNA表达阳性神经元数目。结果模型组大鼠海马各区吖．氨基丁酸能中间神经元SSmRNA表达水平均于出现癫癎持续状态后3d降低最为显著（均P=0．000）,随后逐渐升高;至发病后60d,海马CA3区SSmRNA表达水平高于对照组（t=1．021,P=0．005）,海马门区（t=3．211,P=0．009）和CA1区（t=1．902,JP=0．048）则仍低于对照组。模型组大鼠海马门区γ-氨基丁酸能中间神经元PVmRNA表达水平于出现癫癎持续状态后6h开始降低,至发病后60d降低最为显著（均P：0．000）;海马CA1区PVmRNA表达水平于发病后3d降低最为显著（均p=0．000）,随后逐渐升高但仍低于对照组（t=2．216,尸：0．048）;癫癎持续状态早期,海马CA3区PVmRNA表达水平无明显变化,至发病后7d逐渐升高且高于对照组（t=1．021,P=0．005）。结论γ-氨基丁酸能中间神经元SSmRNA和PVmRNA表达水平的下调可能在颞叶癫癎的发生中起重要作用,至慢性期γ-氨基丁酸能中间神经元SSmRNA和PVmRNA表达水平的恢复或上调可能与颞叶癫癎的发展或修复有关。γ-氨基丁酸能中间神经元数目的变化,部分是由于其标志物mRNA表达水平的调节所致,并非神经元数目变化的唯一因素。     

他莫昔芬对SHG-44胶质瘤细胞氯通道的抑制作用

目的研究氯通道阻断剂他莫昔芬（tamoxifen）对SHG-44胶质瘤细胞电压依赖性氯通道电流的作用。方法采用全细胞膜片钳方法记录SHG-44细胞的电压依赖性氯通道电流，并观察施用不同浓度的他莫昔芬后电流的变化。结果该电流特性为外向整流、不失活，他莫昔芬能够明显阻断该电流，该阻断具有剂量依赖性及电压依赖性。在＋100mV时，1μM及5μM他莫昔芬对氯电流抑制率分别为48％及89％。结论他莫昔芬可明显阻断SHG-44胶质瘤细胞上的电压依赖性氯通道。     

生酮饮食对海人酸点燃癫癎模型大鼠海马神经元保护作用研究

目的探讨生酮饮食对海人酸点燃癫癎模型大鼠海马神经元的保护作用。方法经海人酸制备SD大鼠癫癎模型,分别给予生理盐水+正常膳食(C组)、生理盐水+生酮饮食(K组)、海人酸+正常膳食(E组)和海人酸+生酮饮食(EK组),连续观察21 d后记录不同处理组大鼠体重、观察Ⅳ或Ⅴ级癫癎发作频率和持续时间,并通过HE染色和Nissl染色计数E组和EK组大鼠海马CA3区正常锥体神经元数目。结果 C组和K组大鼠均无癫癎发作,且海马CA3区锥体神经元数目正常。E组和EK组大鼠在观察过程中均出现Ⅳ或Ⅴ级癫癎发作,但EK组大鼠在饲养第21天时与E组相比,癫癎发作频率减少[(17.90±4.12)次对(30.50±4.40)次,P=0.000]、发作持续时间缩短[(212.70±17.75)s对(335.00±14.21)s,P=0.000],差异有统计学意义;EK组海马CA3区正常锥体神经元数目与E组相比增加[(117.67±7.51)个对(71.33±6.11)个,P=0.000],差异亦有统计学意义。结论生酮饮食对海人酸点燃癫癎模型大鼠海马神经元具有保护作用。     

神经元癫癇模型miRNA-212对BDNF/TrkB信号转导通路影响的研究

目的探讨海马神经元癫癇模型转染微小RNA（mi RNA）-212对脑源性神经营养因子（BDNF）/酪氨酸蛋白激酶B（Trk B）信号转导通路的影响。方法经体外培养7 d的大鼠海马神经元（正常对照组）,通过无镁离子细胞外液处理（3 h）方法建立癫癇神经元模型（癫癇模型组）,继而以含镁离子正常细胞外液与慢病毒稀释液转染构建mi RNA-212慢病毒表达载体;免疫荧光双染法、膜片钳技术和免疫印迹法观察转染mi RNA-212对BDNF/Trk B信号转导通路的影响。结果无论是正常海马神经元或癫癇神经元模型,与BDNF共培养后其磷酸化Trk B（p Trk B）/Trk B比值均显著升高（P=0.001）,表明BDNF/Trk B信号转导通路被激活;转染mi RNA-212后,癫癇神经元模型p Trk B/Trk B比值降低并低于未转染者（P=0.001）,提示BDNF/Trk B信号转导通路受到抑制。结论 BDNF具有激活海马神经元BDNF/Trk B信号转导通路作用,而转染mi RNA-212可抑制BDNF/Trk B信号转导通路。     

托吡酯对癫痫大鼠海马细胞外液氨基酸和神经元凋亡的影响

目的研究托吡酯对癫癎大鼠海马区细胞外液氨基酸和神经元凋亡的影响.方法采用戊四氮(PTZ)致癎模型,大鼠癫癎发作后连续给予托吡酯(TPM)80 mg·kg-1·d-1和卡马西平40 mg·kg-1·d-1,共14 d.以TUNEL方法标记DNA片段,原位检测海马凋亡的神经细胞.脑内微透析技术采集大鼠海马细胞外液,反相高效液相色谱技术测定氨基酸类神经递质的含量.结果TPM组、卡马西平组与对照组比较,凋亡细胞数存在显著差异(P＜0.001),TPM组与卡马西平组相比无显著差异(P＞0.05).TPM可明显升高海马细胞外液γ-氨基丁酸(GABA)水平,并降低谷氨酸(Glu)浓度.结论TPM可减轻大鼠癫癎发作后的神经元损伤,这种作用可能是氨基酸变化的结果;但在我们的实验中,没有发现TPM对癫癎后脑损伤比卡马西平有更明显的神经保护作用.     

Fluoxetine inhibits A-type potassium currents in primary cultured rat hippocampal neurons

The effects of fluoxetine (Prozac) on the transient A-currents (IA) in primary cultured hippocampal neurons were examined using the whole-cell patch clamp technique. Fluoxetine did not significantly decrease the peak amplitude of whole-cell K+ currents, but it accelerated the decay rate of inactivation, and thus decreased the current amplitude at the end of the pulse. For further analysis, IA and delayed rectifier K+ currents (IDR) were isolated from total K+ currents. Fluoxetine decreased IA (the integral of the outward current) in a concentration-dependent manner with an IC50 of 5.54 microM. Norfluoxetine, the major active metabolite of fluoxetine, was a more potent inhibitor of IA than was fluoxetine, with an IC50 of 0.90 microM. Fluoxetine (3 microM) inhibited IA in a voltage-dependent manner over the whole range of membrane potentials tested. Analysis of the time dependence of inhibition gave estimates of 34.72 microM(-1) s(-1) and 116.39 s(-1) for the rate constants of association and dissociation, respectively. The resulting apparent Kd was 3.35 microM, similar to the IC50 value obtained from the concentration-response curve. In current clamp configuration, fluoxetine (3 microM) induced depolarization of resting membrane potential and reduced the rate of action potential. Our results indicate that fluoxetine produces a concentration- and voltage-dependent inhibition of IA, and that this effect could affect the excitability of hippocampal neurons.     

快速老化小鼠海马神经元电压门控离子通道特点

目的：观察快速老化小鼠（Senescence-accelerated mouse,SAM)海马神经元的基本离子通道特点，并对抗快速老化亚系（SAM－resistance/1,SAMR1)与快速老化亚系（SAM－prone/8,SMAP8)的基本离子通道特点进行了比较，探讨了离子通道变化在衰老中的可能角度，方法：应用全细胞记录方式，观察并比较原代培养SAMR1和SAMP8海马神经元的电压门控离子通道及膜参数。结果：原代培养SAMR1和SAMP8海马神经元电压门控Na^2 通道电流（INa)和电压门控延迟整流K^ 通道电流（IK）的电学特点和幅度基本一致。SAMP8的电压门控Ca^2 通道电流（ICa)和瞬时外向K^ 通道电流（IA）的幅值则大于相同培养天数的SAMR1。经膜电容校正所得的ICa电流密度也表现出增大的变化规律。结论：SAMP8与SAMR1神经元间IA和ICa的差异可能与其神经系统变异而产生的学习记忆功能下降有关。     

以膜片钳技术急性分离新生大鼠尾核神经元

背景：许多离子通道研究需要单个分散的神经元。人工原代培养的神经细胞受环境的影响,自身特性改变较大,而急性分离的神经元却能相对保持完好的生理特性。 目的：建立急性分离尾核神经元的方法,用膜片钳技术研究尾核神经元离子通道及其信号转到机制,利于深入了解尾核的功能。 设计、时间及地点：以细胞为对象的观察实验,于2008-02/12在三峡大学医学院实验中心完成。 材料：新生7~10 d Wistar乳鼠12只,雌雄不限。 方法：取7~10 d的大鼠,采用酶和机械分离法制备分散的单个尾核神经元,利用全细胞膜片钳技术记录电压依赖性钙电流。 主要观察指标：用全细胞膜片钳急性分离大鼠尾核神经元的形态学视察和电生理特性。 结果：用链蛋白酶(Protease)消化及机械分离法,急性分离的新生大鼠尾核神经元,表面光洁,胞膜完整,有较长的突起,形态和生理特性良好。利用急性分离的新生大鼠尾核神经元观察L-钙离子通道电流,所记录的电学参数在正常生理范围内,较好地保存电压依赖性钙离子通道活性。 结论：分离出的神经元形态正常,有较长的轴突;保存了主要的离子通道活性,成功建立了一种适用于膜片钳技术的大鼠尾核神经元急性分离方法。     

Expression of membrane currents in rat diencephalic neurons in serum-free culture

The whole-cell gigaseal voltage clamp technique has been used to investigate the timing of expression and type of voltage-dependent ionic currents in dissociated primary cultures of fetal rat (E17) diencephalic neurons grown in a serum-free defined medium. The expression of membrane currents varied among cells at any particular time in culture. Despite this variability, certain characteristics of the appearance of ionic currents emerge from this study. These are: (i) the earliest appearing membrane current is a voltage-dependent outward current carried by K+. In some cells, it is the classical delayed rectifier current, whereas in others it is the transient outward current (IA). (ii) The earliest appearing inward current is carried by Na+. In some cells the channels are first expressed in the neurites and then in or near the cell body. The early neuritic Na+ channels are blocked by cobalt or cadmium as well as by tetrodotoxin (TTX). In others, the early Na+ channels appear in or near the cell body and are only blocked by TTX. (iii) With additional time in culture, a majority of cells exhibit a Ca2+ current at the time of Na+ channel appearance in or near the cell body as well as a transient Ca2+-dependent outward current. The Ca2+ current is only a small fraction of the total inward current. These inward currents show the classical pharmacologic profile. The complex pattern of expression of ionic current may reflect multiple populations of neurons with different developmental sequences resulting from differences in cell age and lineage.     

苯妥英对缺氧大鼠大脑皮质神经元钙激活钾通道的影响

目的 :研究苯妥英对缺氧大鼠大脑皮质神经元钙激活钾 [K(Ca) ]通道的影响。方法 :应用膜片钳单通道技术记录苯妥英对缺氧大鼠大脑皮质神经元上K(Ca)通道电流活动。电流信号经放大、滤波及转换后输入微机进行采样、储存和分析。结果 :苯妥英对缺氧大脑皮质神经元K(Ca)通道具有明显的激活作用 ,主要是增加通道的开放概率 (openprobability,Po)。结论 :苯妥英激活大脑皮质神经元K(Ca)通道 ,产生超极化电位 ,从而稳定细胞膜 ,降低细胞兴奋性 ,延缓缺氧除极的发生 ,这可能是苯妥英抗缺血脑损伤的另一个重要机制     

Development of the fast, transient outward K current in embryonic sympathetic neurones

Voltage-activated outward potassium (K+) currents in developing sympathetic neurones, dissociated from the rat superior cervical ganglion (SCG), were studied using the whole-cell patch clamp recording technique. In voltage-clamped neonatal SCG cells, two voltage-dependent K+ currents were measured: the fast, transient K+ current, IA; and, the slower activating, non-inactivating delayed rectifier, IK. Only IK, however, appeared to be present in SCG neurones isolated from early embryonic (E14.5-16.5) rat pups; IA was not observed in these cells. When these embryonic neurones were maintained in cell culture, IA developed over a time course (approximately 4-6 days) similar to that seen in vivo. IA, therefore, which appears to facilitate the fast repolarization phase of the action potential in rat SCG neurones, is the last voltage-activated current to develop in these cells.     

Expression of membrane currents in rat neocortical neurons in serum-free culture. I. Inward currents

The gigaseal whole-cell voltage clamp technique has been used to investigate the timing of expression and properties of voltage-dependent inward currents in cultured neocortical pyramidal-shaped neurons. The dissociated primary cultures of synchronized (same cell cycle), growth arrested (G1-phase) and birth-dated neurons from fetal rat (E18) were maintained in a serum-free medium. The earliest inward current is expressed within 24 h. This current is carried by Na+ and the channels are located in distal neurites at discrete sites. The Na+ channels near the cell body are expressed after 5 days in culture, at which time the neuritic Na+ current persists. The magnitude of the current near the soma increases with age of the neuron. The Na+ current is blocked by both tetrodotoxin (TTX) and nitrendipine. The sensitivity to nitrendipine changes with age of the culture. The results suggest that Na channels expressed early during neuronal development have some structural component common also to Ca2+ channels.     

皮质酮对体外培养的大鼠海马神经元膜电位的影响

为探讨应激激素－皮质酮以违法乱纪 马神经细胞膜电位的影响,采用膜片钳全细胞记录的方法,测量了原代培养的大鼠马神经细胞膜的静脉电位。结果发现,在皮质酮的作用下,海马神经静息电位幅值明显降低,细胞膜呈去极化。     

Interleukin-1 beta depresses calcium currents in CA1 hippocampal neurons at pathophysiological concentrations.

Interleukin-1 is present in the central nervous system (CNS) during acute and chronic pathological processes. In the present study, we examined the interaction between recombinant human interleukin-1 beta (rhIL-1 beta) and the voltage-dependent calcium (Ca2+) current using the whole-cell patch clamp technique. RhIL-1 beta depressed the voltage-gated Ca2+ current in acutely dissociated guinea pig hippocampal CA1 neurons. This depression is rapid and is observed at pathophysiological concentrations (greater than or equal to 1.97 pg/10 microliters). Concomitant application of rhIL-1 beta and rhIL-1 receptor antagonist had no effect indicating neuroactive specificity of rhIL-1 beta. The depression of the inward Ca2+ current by IL-1 beta may play a role in: 1) the regulation of neuronal excitability; 2) the induction of neurological manifestations during disease; and 3) in the induction and/or progression of neurodegenerative processes.