豚鼠背侧海马锥体细胞自发放电特征

实验采用细胞外玻璃微电极采集豚鼠海马神经元放电信号,并将信号转化为峰峰间期(interspike interval,ISI)以研究麻醉和清醒状态海马锥体细胞自发放电线性和非线性特点。实验建立了豚鼠海马锥体细胞与中间神经元电生理鉴别标准;麻醉和清醒状态下豚鼠海马CA1和CA3区锥体细胞自发放电频率、时程、复杂度等无显著区别;麻醉组豚鼠海马锥体细胞ISI序列的复杂度小于清醒组,锥体细胞分型和ISI变异度等表现不同。实验表明,麻醉和清醒状态下豚鼠海马锥体细胞自发放电呈不同线性和非线性特征。传统和非线性研究手段的结合,可能较全面地反映海马锥体细胞自发放电特性。     

谷氨酸对海马CA1区锥体细胞A-电流特性的影响

利用全细胞膜片钳记录方法,在急性分离的大鼠海马CA1区锥体细胞上深入研究了谷氨酸对方波诱导的短暂性外向钾电流（IA）激活和失活特性的影响。结果发现：在谷氨酸灌流条件下,IA的激活时间常数没有明显改变（P＞0 ．05）,谷氨酸升高了A－通道稳态失活电压;谷氨酸延长了A－电流失活时间,并具有电压依赖性。实验结果说明了谷氨酸从不同的方面调控着A－通道,对A－通道稳态失活电压依赖性的改变可能是其调控A－通道的主要途径。     

大鼠海马CA1区锥体细胞的急性分离和鉴定

目的：建立一种适用膜片钳技术的大鼠海马ＣＡ１区锥体细胞的急性分离方法,并对其进行鉴定。方法：采用酶加机械分离法制备７～１０ｄ鼠龄的大鼠海马ＣＡ１区锥体细胞,用免疫荧光技术鉴定神经元,其电生理学特性测定用全细胞膜片钳技术。结果：分离的锥体细胞是海马ＣＡ１区锥体细胞,且具有正常的电生理学特性,并保存了某些主要的电压依赖性和受体依赖性离子通道特性。结论：成功地建立了一种简单、快速、高产的适用于膜片钳技术的大鼠海马ＣＡ１区锥体细胞的急性分离方法。     

慢性应激对大鼠学习记忆能力和海马LTP的影响

目的和方法：本研究采用一种多因素的２１ｄ慢性应激动物模型,以Ｙ迷宫和ＬＴＰ为指标,探讨慢性应激对运动学习记忆能力和海马神经突触可塑性的影响。结果：长期慢性应激使大鼠空间学习记忆能力下降,而且,使中枢海马齿状回ＬＴＰ的诱生受到抑制。结论：慢性应激可能使大鼠海马齿状回神经突触可塑性降低,并进一步影响到学习记忆的功能。     

人体海马CA1区锥体细胞胞体的发育

目的：探究人体海马CA1区神经元锥体细胞胞体发育的过程。方法：取19孕周（19GW）、20GW、26GW、35GW、38GW水囊引产胎儿和8岁（8Y）死亡儿童各1例,所有标本来源符合相关法律法规和伦理要求,采用Golgi染色技术,借助配备有＂Neurolu-cida＂软件的共聚焦显微镜观察CA1区锥体细胞胞体,分析细胞体的长度和面积。结果：19GW和20GW细胞体形态尚不明显。26Gw、35Gw、38Gw、8Y海马CA1区锥体神经元胞体长度分别为56．5±2．5（μm）、80．8±8．5（μm）、85．9±12．2（μm）、91．3±9．6（μm）;胞体面积分别为254．5±13．7（μm^2）、362．5±15．5（μm^2）、380．5±22．8（μm^2）、460．8±25．7（μm^2）。26GW锥体细胞胞体长度和面积与35GW、38GW、8Y相比差异明显（P〈0．05）;8岁胞体长度和面积与38GW相比有小幅度增大;细胞形态学：26GW、35GW、38GW锥体细胞胞体切面呈椭圆形或三角形,随胎龄增大,胞体长度和面积逐渐增长增大,特别是细胞基底部增宽。胞体形态由椭圆形逐渐转换为三角形;细胞底部的基树突数量也逐渐增加,到38GW时可以达到4—7个,8Y锥体细胞胞体在切面上基本上都呈三角形,细胞长度和面积与38GW相比稍微增大,相对趋于稳定。结论：人体在发育过程中,锥体细胞长度呈逐渐增长、面积呈逐渐增大趋势,26GW与35GW之间变化最大,38GW与8Y胞体面积差异不明显,整个变化趋势逐渐变慢并趋于稳定。     

人体海马CA1 区锥体细胞胞体的发育

目的:探究人体海马CA1区神经元锥体细胞胞体发育的过程。方法:取19孕周(19GW)、20GW、26GW、35GW、38GW水囊引产胎儿和8岁(8Y)死亡儿童各1例,所有标本来源符合相关法律法规和伦理要求,采用Golgi染色技术,借助配备有"Neurolu-cida"软件的共聚焦显微镜观察CA1区锥体细胞胞体,分析细胞体的长度和面积。结果:19GW和20GW细胞体形态尚不明显,26GW、35GW、38GW、8Y海马CA1区锥体神经元胞体长度分别为56.5±2.5(μm)、80.8±8.5(μm)、85.9±12.2(μm)、91.3±9.6(μm);胞体面积分别为254.5±13.7(μm2)、362.5±15.5(μm2)、380.5±22.8(μm2)、460.8±25.7(μm2)。26GW锥体细胞胞体长度和面积与35GW、38GW、8Y相比差异明显(P<0.05);8岁胞体长度和面积与38GW相比有小幅度增大;细胞形态学:26GW、35GW、38GW锥体细胞胞体切面呈椭圆形或三角形,随胎龄增大,胞体长度和面积逐渐增长增大,特别是细胞基底部增宽,胞体形态由椭圆形逐渐转换为三角形;细胞底部的基树突数量也逐渐增加,到38GW时可以达到4-7个,8Y锥体细胞胞体在切面上基本上都呈三角形,细胞长度和面积与38GW相比稍微增大,相对趋于稳定。结论:人体在发育过程中,锥体细胞长度呈逐渐增长、面积呈逐渐增大趋势,26GW与35GW之间变化最大,38GW与8Y胞体面积差异不明显,整个变化趋势逐渐变慢并趋于稳定。     

P物质抑制培养大鼠海马大锥体细胞GABA—激活电流

研究主要探讨P物质（SP）对GABA－激活电流的调制。实验在培养的新生大鼠海马大锥体细胞上进行。应用全细胞膜片箝技术记录GABA激活的内向电流。在被检的大锥体细胞中,有72％（66／92）的神经元对GABA和SP同时敏感,预后SP后,GABA激活电流明显地被抑制,此抑制作用是呈剂量依赖性的。在预加10^-8,10^-7,10^-6,10^-5mol/LSP后,GABA的激活电流分别降低18％,24．8％,25．9％和28％,用SP的拮抗剂 spantide能阻断此种抑制作用,在电极中灌注H7（PKC抑制剂）能取消此抑制作用,上述结果提示：SP对GABA激活电流的抑制作用是SP作用于SP受体,通过胞内第二信使,使GABAA受体通道复合体胞内磷酸化所致。     

体力运动减缓慢性应激对海马的损伤作用

为探讨体力运动对慢性应激引起的海马损伤的影响,在大鼠整体水平检测海马长时程增加（long-term potentiation,LTP）和血浆糖皮质激素（glucocorticoids,GCs）水平,结果发现,8周的跑轮运动（wheel running)会明显减缓随后21d的慢性束缚应激对海马齿状回（dentate gyrus,DG)LTP的抑制,且可维持血浆GCs水平正常,结果提示,长期体力运动对海马有保护作用,可减缓慢性应激引起的损伤。     

慢性应激抑郁大鼠学习记忆及海马非对称性超微结构的改变

目的：探讨慢性不可预见性应激抑郁模型大鼠大脑海马非对称性超微结构与学习记忆能力的改变。方法：SD雄性大鼠20只,随机分为正常对照组与抑郁模型组,每组10只。采用慢性轻度不可预见性应激21d及单笼饲养方法建立抑郁模型,应激前以及应激21d末对两组大鼠进行旷场实验、液体消耗实验及体重测量,对大鼠进行避暗穿梭实验,测试其学习记忆能力,之后活杀动物,取出大鼠左右海马,制作常规电镜标本,观察海马超微结构的改变。结果：在穿梭变实验中抑郁大鼠学习记忆潜伏期减少,进入暗箱错误积分增多。抑郁大鼠左右侧海马超微结构中左侧海马较正常对照组神经细胞及胶质细胞变化明显,表现为内质网扩张,溶酶体增多。而右侧海马远不及左侧损伤严重。结论：慢性不可预见性应激抑郁大鼠学习记忆能力显著下降,其可能与海马组织在应激过程受到的累积损伤有关,且抑郁大鼠海马损伤呈非对称表现。     

慢性应激大鼠海马的比较蛋白质组学研究

慢性应激可造成海马神经细胞丢失、树突萎缩等损伤,但有关其损伤机制仍有很多问题不甚明了.为了寻找应激致海马损伤相关的重要蛋白质、从蛋白质水平揭示应激致海马损伤的分子机制,应用双向凝胶电泳(2-DE)技术分离对照组和束缚应激组大鼠海马组织总蛋白质,图像分析检测差异表达的蛋白质点,基质辅助激光解析电离飞行时间质谱(MALDI-TOF-MSS)和数据库检索对差异表达的蛋白质点进行鉴定,并采用半定量的RT-PCR在mRNA水平验证2-DE结果.得到了分辨率较高、重复性较好的对照和束缚应激大鼠海马2-DE图谱,质谱分析和数据库检索鉴定了14个差异表达蛋白质点中的11个蛋白质,大多数差异蛋白的功能涉及能量代谢、信号传递等过程.研究结果为揭示应激致海马损伤的机制、提高机体的应激适应能力提供了理论依据.     

海马区锥体神经元轴突高频电刺激对胞体的影响

目的 深部脑刺激（deep brain stimulation,DBS）利用持续的电脉冲高频刺激（high-frequency stimulation,HFS）调控神经元的活动，可望用于治疗更多脑疾病。为了深入了解HFS的作用机制，促进DBS的发展，本文研究轴突HFS在引起轴突阻滞期间神经元胞体的改变。方法 在麻醉大鼠海马CA1区的锥体神经元轴突上施加脉冲频率为100 Hz的1 min逆向高频刺激（antidromic high-frequency stimulation,A-HFS）。为了研究胞体的响应，利用线性垂直排列的多通道微电极阵列，记录刺激位点上游CA1区锥体神经元胞体附近各结构分层上的诱发电位，包括A-HFS脉冲诱发的逆向群峰电位（antidromic population spike,APS）以及A-HFS期间施加的顺向测试脉冲诱发的顺向群峰电位（orthodromic population spike,OPS），并计算诱发电位的电流源密度（current-source density,CSD），用于分析A-HFS期间锥体神经元胞体附近动作电位的生成和传导。结果 锥体神经...     

Effects of Ginkgo Biloba Extract Constituents on Glycine-Activated Strychnine-Sensitive Receptors in Hippocampal Pyramidal Neurons of the Rat

Active compounds of Ginkgo biloba extract (ginkgolides A, B, C, and J) were tested on the main ligand-operated conductances in rat neurons using a patch-clamp technique in the whole-cell configuration and a concentration-clamp technique. It was found that all ginkgolides reduced glycine-activated currents in concentration- and use-dependent manners, whereas they did not affect other tested ligand-gated receptors (NMDA- and GABA-activated ones). The IC₅₀ values calculated from dose-response curves were as follows: 1.97, 0.273, 0.267, and 2.0 M for ginkgolides A, B, C, and J, respectively (200 M Gly ).The Hill coefficient in all cases was close to 1.0, which indicates a single site of the drug binding to the glycine-activated receptor.     

乌拉坦对大鼠海马CA1区锥体神经元自发放电的抑制作用

为了深入研究麻醉药乌拉坦对大鼠海马CA1锥体神经元自发放电的作用及其机制,分析了10 mmol/L乌拉坦对自发放电、电压门控钠通道、电压门控钾通道的作用．从自发放电信号中计算了放电频率、提取了峰峰间隔序列(ISI)并利用样品熵和去趋势波动法对ISI进行了非线性分析．结果表明,乌拉坦不仅抑制了自发放电的频率,而且降低了自发放电ISI序列的复杂度并弱化了其长时程相关性．离子通道研究结果表明,乌拉坦显著地抑制了钠通道电流(I_Na),对延迟整流钾通道电流(I_K)和瞬时外向钾通道电流(I_A)虽然也有抑制作用但无统计学意义．由于乌拉坦不影响突触传递,因此它可能通过抑制I_Na使自发放电的阈值升高而降低放电频率,同时,由于参与的通道数量或活性降低而使得ISI的复杂度下降,长时程相关性弱化．     

Hippocampal CA1 Pyramidal Cell Size is Reduced in Bipolar Disorder

1. Schizophrenia and bipolar disorder are neurodevelopmental disorders with significant genetic vulnerabilities. Several trophic genes and/or proteins have been implicated in the causation for both disorders. 2. We hypothesized that these genes and/or proteins may impact neuronal growth in both disorders. 3. Hippocampal tissue sections from CA1 area of schizophrenic, bipolar, depressed, and controls subjects, matched for age, sex, PMI, drug exposure, and brain pH were prepared for cell size determination using the Stanley Medical Research Foundation postmortem brain collection. 4. Quantification of hippocampal CA1 pyramidal neuron size showed a significant 12% reduction in cell size (p < 0.05) in bipolar subjects vs. controls. There were nonsignificant trends for reduction in cell size in both schizophrenic and depressed subjects vs. controls. 5. These results indicate for the first time that pyramidal cell atrophy is present in hippocampus of subjects with bipolar disorder.     

Medial and Lateral Entorhinal Cortex Differentially Excite Deep versus Superficial CA1 Pyramidal Neurons

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Calcium Channels in the Nuclear Envelope of Pyramidal Neurons of the Rat Hippocampus

As is known, an increase in the concentration of Са²⁺ in the nuclei of nerve cells leads to activation of genes responsible for the formation of long-lasting postsynaptic changes; mechanisms of memory and learning are based on such changes. The pathways necessary for the entry of calcium into the nuclei of hippocampal pyramidal neurons remained unstudied. Using a patch-clamp technique, we studied what types of calcium channels exist in the membranes of isolated nuclei of pyramidal neurons of the hippocampal СА1 area. In the inner nuclear membrane of these cells, we, for the first time, found inositol trisphosphate receptors (IP₃Rs) activated by inositol trisphosphate applied in the concentration of ≥0.1 μM. The conductivity of single channels of such receptors was, on average, 366 pS; these channels were permeable for both monovalent and bivalent cations. Our data indicate that the nuclear envelope of pyramidal neurons of the hippocampal СА1 area can play the role of the calcium store from which Са²⁺ enter the cell nucleus directly. Neirofiziologiya/Neurophysiology, Vol. 40, No. 4, pp. 288–292, July–August, 2008.     

An Ibotenate-Selective Metabotropic Glutamate Receptor: Mediates Protein Phosphorylation in Cultured Hippocampal Pyramidal Neurons

Abstract: Previous results showed that within 30 s after glutamate stimulation of cultured rat hippocampal pyramidal neurons there occurred an elevation of Ca²⁺ and diacylglycerol, and the phosphorylation of three acidic protein kinase C substrates, i.e., an 87-kDa protein known as myristoylated alanine-rich C kinase substrate and a 120-and a 48-kDa protein. In addition, it was suggested that a metabotropic-type glutamate receptor might be responsible for the phosphorylation observed. This work examines the ability of metabotropic and ionotropic glutamate receptor agonists to quickly activate phospholipases in 1.26 mM versus 50 nM extracellular Ca²⁺ by measuring the generation of inositol phosphates. NMDA, quisqualate, and trans-(±)-1-amino-1,3-cyclopentanedicarboxylic acid did not stimulate the generation of inositol phosphates in the presence of normal or low extracellular Ca²⁺ in pyramidal neurons. Kainate stimulated the production of inositol phosphates in the presence of 1.26 mM extracellular Ca²⁺ but not in 50 nM extracellular Ca²⁺. Other than glutamate, only ibotenate was able to stimulate the generation of inositol phosphates in both normal and low extracellular Ca²⁺. The maximal response to ibotenate was approximately equal to that of glutamate, when pyramidal neurons were stimulated in 50 nM extracellular Ca²⁺. The generation of inositol phosphates by glutamate and ibotenate could be partially blocked (50–60% reduction) by pretreatment of neurons with pertussis toxin (250 ng/ml),-suggesting that a GTP-binding protein might be involved. In addition, ibotenate stimulated the immediate phosphorylation of the same three protein kinase C substrates as glutamate. The NMDA receptor blocker MK-801 had no effect on this phosphorylation. These results suggest that the stimulation of phosphorylation in pyramidal neurons by glutamate occurs predominantly through the activation of an ibotenate-selective metabotropic glutamate receptor.     

束缚应激对大鼠同型半胱氨酸代谢的影响

为了探讨束缚应激对大鼠血清含硫氨基酸代谢的影响,根据同型半胱氨酸(Hcy)水平,将32只雄性Wistar大鼠分为对照组(control)、束缚应激组(RS)、1%蛋氨酸组(1%Met)和1%蛋氨酸+束缚应激组(1%Met+RS)。采用高压液相色谱法检测血清中的Hcy、半胱氨酸(Cys)和还原型谷胱甘肽(GSH)含量,采用全自动氨基酸分析仪测定血清中蛋氨酸(Met)和牛磺酸(Tau)含量。结果显示,RS组大鼠血清Hcy、Cys和GSH含量随着束缚时间延长而降低,且较对照组和1%蛋氨酸组有显著性差异(p<0.05);RS组大鼠血清Met和Tau含量较对照组和1%蛋氨酸组则显著升高(p<0.05)。束缚应激可能降低血清抗氧化能力和总Hcy水平。     

钾通道在培养大鼠海马神经元凋亡性容积减少中的作用

为探讨钾通道参与神经元凋亡的可能机制,在星形孢菌素（STS)诱导的培养海马神经元凋亡模型上,研究了凋亡时神经细胞容积的动态变化及钾通道在其中的作用.实验结果显示,钾通道阻断剂四乙铵或升高细胞外K⁺均能够明显抑制STS诱导的神经元凋亡,并且大电导钙激活钾通道（BK）选择性阻断剂iberiotoxin和paxilline具有同样程度的抗细胞凋亡作用,表明钾通道（可能主要是BK通道）参与了STS诱导的培养海马神经元凋亡.在STS诱导神经元凋亡的早期就出现了细胞容积的显著减少,而钾通道阻断剂或升高细胞外K⁺均可阻断该细胞容积减少.研究结果提示细胞内钾离子的外流可能参与了凋亡性细胞容积减少,这也可能是钾通道介导细胞凋亡的重要机制之一.