红藻氨酸致癫痫大鼠不同时点神经生长因子变化研究

摘要: 目的 探讨红藻氨酸( Kainic Acid,KA) 致癫痫大鼠癫痫发作过程中海马组织神经生长因子( nerve growth factor,NGF) 不同时间点表达量的变化。方法 腹腔注射 KA 建立大鼠癫痫模型。采用 TaqMan 探针实时定量 PCＲ ( Ｒeal-time quantitative PCＲ) 技术,检测注射 KA 后不同时点大鼠海马组织中 NGF 表达量的变化。结果 与 NGF 表达量与生理盐水对照组( NS) 相比,6 ～ 12 h NGF 表达量明显低于 NS 组( P ＜ 0. 05) 、48 ～ 72 h NGF 表达量开始升高并高于 NS 组,在 24、72 h 时其表达量显著高于 NS 组( P ＜ 0. 05) 。结论 NGF 对致癫大鼠的海马具有修复与保护作用。     

不同致惊药物对小鼠不同脑区~3H-GABA与GABA_A受体结合的影响

用放射配体受体结合分析法,测定致惊药物红藻氨酸（ｋａｉｎｉｃ, Ｋ Ａ）和印防己毒素（ｐｉｃｒｏｔｏｘｉｎ, Ｐｉｃ）对小白鼠下丘脑、大脑皮层、海马、小脑四个脑区３ Ｈ Ｇ Ａ Ｂ Ａ 和 Ｇ Ａ Ｂ Ａ Ａ 受体结合的影响。结果显示, Ｋ Ａ、 Ｐｉｃ均能明显降低各脑区３ Ｈ Ｇ Ａ Ｂ Ａ和 Ｇ Ａ Ｂ Ａ Ａ 受体的结合量,除 Ｐｉｃ 对下丘脑无显著差异外,其余均有显著性差异（ Ｐ＜０．０５ 或 Ｐ＜ ０．０１）。实验结果提示： Ｋ Ａ 和 Ｐｉｃ均能降低 Ｇ Ａ Ｂ Ａ Ａ 受体的结合量,但是它们是通过不同的途径间接或直接地影响 Ｇ Ａ Ｂ Ａ 能系统活动的     

孕烯醇酮和孕烯醇酮硫酸盐对小鼠不同脑区^3H—GABA与GABAB受体结合的影响

采用放射配体受体结合分析法,研究了孕烯醇酮（Pe）和孕烯醇酮（Pes)对小鼠不同脑区^3H-GABA与GABAB受体结合的影响。结果显示,Pe对小鼠下丘脑、大脑皮层、海马、小脑GABAB受体的结合均有抑制效应,且能被GABAB受体激动剂巴氯芬（Bac)所阻断并翻转。Pes对大脑皮层、海马、小脑GABAB受体的结合有抑制作用,而对下丘脑则有促进作用。Bac能阻断Pes的抑制作用（海马除外）,加强Pes的促进作用。实验结果提示,Pe,Pes对各脑区GABAB受体的结合具有一定的影响作用,且多为抑制效应。     

~3H—GABA在小白鼠脑中的积聚

应用同位素示踪法,对~3H-GABA在小鼠脑各不同脑区(皮层、海马、下丘脑和尾核)中的积聚进行了研究。~3H-GABA的积聚以海马为最多,皮层和下丘脑次之,尾核较少,脑室注射1.25×10~(-5)μmole/kg体重的~3H-GABA 1小时的积聚量为10~(-7)μmole/mg脑重。~3H-GABA可少量通过血脑屏障,透过量在12小时内为10~(-8)μmole/mg脑重。氨氧乙酸(AOAA)使~3H-GABA在脑中的积聚明显增加,木防已苦毒(Picrotoxin)和海人酸(Kainic acid)使积聚减少,谷氨酸对积聚无明显影响。     

小白鼠全脑切片^3H—GABA的摄取以及抑制物对摄取的影响

在36℃培育的小白鼠脑切片对~3H-GABA的摄取是浓度依赖性的、可饱和的,当2ml培育液中注入100μl浓度为215×10~(-4)mol/L的~3H-GABA时,脑片对~3H-GABA的摄取达到饱和。3℃时切制脑片能获得较好的~3H-GABA摄取效果。苄青霉素钾(PG)7.6×10~(-4)mol/L、苯巴比妥钠(PhB)9.8×10~(-4)mol/L、Gabaculline 4.0mol/L各100μl均使脑片对~3H-GABA的摄取明显下降,荷包牡丹碱(BiC)0.25×10~(-4)mol/L、氨氧乙酸(AOAAA)1.0×10~(-4)mol/L可使脑片对~3H-GABA的摄取明显上升。     

孕烯醇酮和孕烯醇酮硫酸盐对小鼠不同脑区~3H-GABA与GABA_B 受体结合的影响

采用放射配体受体结合分析法 ,研究了孕烯醇酮 (Pe)和孕烯醇酮硫酸盐 (Pes)对小鼠不同脑区3H GABA与GABAB 受体结合的影响 .结果显示 ,Pe对小鼠下丘脑、大脑皮层、海马、小脑GABAB 受体的结合均有抑制效应 ,且能被GABAB 受体激动剂巴氯芬 (Bac)所阻断并翻转 .Pes对大脑皮层、海马、小脑GABAB 受体的结合有抑制作用 ,而对下丘脑则有促进作用 .Bac能阻断Pes的抑制作用 (海马除外 ) ,加强Pes的促进作用 .实验结果提示 ,Pe ,Pes对各脑区GABAB 受体的结合具有一定的影响作用 ,且多为抑制效应     

东亚钳蝎提取物对致痫小鼠大脑GABAA受体活性的影响

目的:研究东亚钳蝎提取物对戊四氮致痫小鼠发作潜伏期的作用并探讨其机理。方法:采用戊四氮致痫小鼠模型,给予实验动物东亚钳蝎提取物灌胃,并以丙戊酸钠为对照,观察其对致痫小鼠发作潜伏期和大脑GABAA受体结合活性的影响。结果:东亚钳蝎提取物中剂量组(500 mg/kg)的惊厥潜伏期比模型鼠明显延长(p<0.05),大脑皮层GABAA受体的结合活性显著提高(p<0.001)。低剂量(250 mg/kg)和高剂量(1 000 mg/kg)治疗组与阳性对照药的作用相当。结论:东亚钳蝎提取物的抗癫痫作用机理可能与提高大脑皮层GABAA受体的结合活性有关。     

孕烯醇酮和孕烯醇酮硫酸盐对小鼠全脑切片摄取3H-γ-氨基丁酸的影响

用离体脑片培养和同位素示踪法 ,研究了不同浓度 ( 0 .0 1～ 10 0μmol/L )的孕烯醇酮 ( Pe)和孕烯醇酮硫酸盐( Pes)对小鼠全脑切片摄取 3 H-γ-氨基丁酸 ( 3 H-GABA)的影响 .结果表明 :0 .0 1～ 0 .0 5 μmol/L Pe使 3 H-GABA的摄取量增加 ,而 10～ 10 0μmol/L Pe使摄取量降低 ( P均 <0 .0 0 1) .0 .0 1～ 10μm ol/L Pes对 3 H -GABA的摄取无显著影响 ,而 10 0 μmol/L 的 Pes使摄取量显著增加 ( P<0 .0 0 1) .用印防己毒素、荷包牡丹碱、戊巴比妥钠和巴氯芬分别与 0 .0 1μm ol/L Pe共同使用 ,均能明显增加脑片对 3 H-GABA的摄取 ( P<0 .0 5或 P<0 .0 0 1) .以上结果提示 ,Pe、Pes均能通过影响 GABA的摄取而调节 GABA能系统的活动 ,其影响效应与 Pe、Pes的浓度密切相关 .     

酒精对大鼠外侧穿通纤维-CA3区LTP诱导的影响

目的:研究酒精对大鼠外侧穿通纤维(lateral perforant path,LPP)-CA3区(LPP-CA3)长时程增强(long-term potentiation,LTP)诱导阶段的影响及可能的机制.方法:用细胞外电生理记录方法,通过向海马CA3区分别微量注射酒精(Alcohol)、阿片受体拮抗剂纳洛酮(naloxone)和GABAA受体拮抗剂荷包牡丹碱(bicucul-line,BIC),以海马CA3区群体兴奋性突触后电位(field excitory postsynaptic potentials,fEPSP)斜率改变为指标,观察高频刺激引起的LTP诱导的变化.结果:①酒精剂量依赖性地抑制LTP的诱导;②纳洛酮和BIC均可以部分减轻酒精对LTP诱导的抑制作用.结论:内源性阿片系统和GABA能系统参与了酒精对LPP-CA3通路LTP诱导的调制.     

蓝布正总提取物对高血糖动物降血糖作用的研究

目的:研究蓝布正对几种物质诱导高血糖动物血糖的影响.方法:用葡萄糖及肾上腺素致小鼠高血糖模型、四氧嘧啶致糖尿病小鼠模型,分别观察蓝布正对小鼠血糖、体重、饮水量和饮食量的影响.结果:蓝布正低、高剂量组都能降低葡萄糖性高血糖小鼠的血糖水平(P＜0.05).高剂量组能显著降低肾上腺素性高血糖小鼠的血糖水平(P＜0.05):低剂量组对肾上腺素性高血糖模型无明显降低作用(P＞0.05);低高剂量组均能显著降低四氧嘧啶致糖尿病小鼠的血糖水平(P＜0.05,P＜0.01),且呈一定的剂量依赖关系;还能减少动物的饮食及饮水量.结论:蓝布正对多种原因引起的高血糖均有一定的降糖作用.     

孕酮对小鼠不同脑区和卵巢、子宫中[~3H]-GABA 与 GABA_A 受体结合的影响

采用放射配体受体结合分析的方法，研究了小鼠大脑皮层、小脑、海马、下丘脑四个脑区和卵巢、子宫中孕酮对外源性［３Ｈ］－ＧＡＢＡ与ＧＡＢＡＡ受体结合的影响，结果表明：１）孕酮使中枢四个脑区和子宫中外源性［３Ｈ］－ＧＡＢＡ的结合量显著下降；２）ＧＡＢＡＡ受体拮抗剂Ｐｉｃｒｏ－ｔｏｘｉｎ与孕酮＋Ｐｉｃｒｏｔｏｘｉｎ对［３Ｈ］－ＧＡＢＡ结合的影响无明显差别；３）在卵巢中孕酮对［３Ｈ］－ＧＡＢＡ与ＧＡＢＡＡ受体的结合无明显影响。这表明中枢和子宫存在的孕酮，能降低ＧＡＢＡＡ受体对外源性［３Ｈ］－ＧＡＢＡ的结合，而且可被Ｐｉｃｒｏｔｏｘｉｎ所拮抗，提示孕酮可能通过影响ＧＡＢＡＡ的功能，发挥巴比妥样效应，并且其作用位点可能与Ｐｉｃｒｏｔｏｘｉｎ的位点靠近。     

药物对小白鼠不同脑区GABA_A受体与外源性GABA_A结合的影响

用同位素示踪法测定药物对小鼠四个不同脑区的GABA_A受体与外源性GABA结合的影响。GABA_A受体颉颃剂Picrotoxin,bicuculline,青霉素,和GABA-T抑制剂AOAA均使大脑皮层的受体结合显著增加,中枢兴奋剂戊四唑使之显著地减少。AOAA使海马的受体结合显著增加,戊四唑及安定使之显著减少。蝎毒使下丘脑的受体结合显著增加,而戊四唑使之显著减少。AOAA、蝎毒、bicuculline、picrotoxin使小脑的受体结合显著增加。     

青霉素惊厥与脑中GABA_A和GABA_B受体亲和力的关系

脑室微量注射青霉素（１１．９ｍｇ·ｍｌ－１，１５μｌ）制作小白鼠惊厥模型；并以同位素示踪法研究大脑皮层、小脑、海马、下丘脑四个脑区ＧＡＢＡＡ和ＧＡＢＡＢ受体亲和力的变化。结果显示，青霉素惊厥时大脑皮层和小脑ＧＡＢＡＡ受体亲和力显著减弱，而海马、下丘脑ＧＡＢＡＡ受体亲和力无变化；青霉素惊厥使四个脑区中ＧＡＢＡＢ受体均显著下降。提示，除了海马和下丘脑的ＧＡＢＡＡ受体以外，四个脑区的ＧＡＢＡＡ和ＧＡＢＡＢ受体均参与了青霉素的致惊厥过程。青霉素可能通过竞争内源性ＧＡＢＡ与ＧＡＢＡＡ和ＧＡＢＡＢ受体的结合，阻断了ＧＡＢＡ介导的突触前和突触后抑制效应并增加了兴奋性递质的释放，显示了惊厥效应。     

Co-localization of GABA receptors and benzodiazepine receptors in the brain shown by monoclonal antibodies

The most abundant inhibitory neurotransmitter in the central nervous system, gamma-aminobutyric acid (GABA), exerts its main effects via a GABAA receptor that gates a chloride channel in the subsynaptic membrane. These receptors can contain a modulatory unit, the benzodiazepine receptor, through which ligands of different chemical classes can increase or decrease GABAA receptor function. We have now visualized a GABAA receptor in mammalian brain using monoclonal antibodies. The protein complex recognized by the antibodies contained high- and low-affinity binding sites for GABA as well as binding sites for benzodiazepines, indicative of a GABAA receptor functionally associated with benzodiazepine receptors. As the pattern of brain immunoreactivity corresponds to the autoradiographical distribution of benzodiazepine binding sites, most benzodiazepine receptors seem to be part of GABAA receptors. Two constituent proteins were identified immunologically. Because the monoclonal antibodies cross-react with human brain, they provide a means for elucidating those CNS disorders which may be linked to a dysfunction of a GABAA receptor.     

Anatomical distributions of four pharmacologically distinct 3H-L-glutamate binding sites

Glutamate is thought to serve as a major excitatory neurotransmitter throughout the central nervous system (CNS); electrophysiological studies indicate that its action is mediated by multiple receptors. Four receptors have been characterized by their selective sensitivity to N-methyl-D-aspartate (NMDA), kainic acid (KA), quisqualic acid (QA) and 2-amino-4-phosphonobutyric acid (APB). Electrophysiological evidence indicates that these receptors are all present in the rat hippocampus and that the anatomically discrete synaptic fields within the hippocampus exhibit differential sensitivity to the selective excitatory amino acid agents. Thus, we have used the hippocampus as a model system to investigate possible subpopulations of 3H-L-glutamate binding sites. By using quantitative autoradiography, the pharmacological specificity of 3H-L-glutamate binding in discrete terminal fields was determined. We report here that there are at least four distinct classes of 3H-L-glutamate binding sites which differ in their anatomical distribution, pharmacological profile and regulation by ions. Two of these sites seem to correspond to the KA and NMDA receptor classes, and a third site may represent the QA receptor. The fourth binding site does not conform to present receptor classifications. None of these binding sites corresponds to the major glutamate binding site observed in biochemical studies.     

实验性癫痫大鼠补体C3b受体的表达

目的：建立大鼠的实验性癫痫模型，探讨实验性癫痫大鼠补体C3b受体的表达，进一步揭示癫痫的免疫炎症机制．方法：采用皮下注射海仁酸方法建立实验性癫痫大鼠模型；采用免疫组织化学染色方法观察实验性癫痫大鼠补体C3b受体的表达．结果：给大鼠皮下注射海仁酸可成功地建立实验性癫痫大鼠模型，其大脑海马锥状细胞层可见到神经元的变性，并可见补体C3b受体的明显表达．结论：实验性癫痫大鼠大脑海马硬化发生过程中，存在着补体系统参与的免疫反应发生，并引起炎症反应、     

A site for the potentiation of GABA-mediated responses by benzodiazepines

The benzodiazepines have been well characterised as minor tranquillizers and attempts to explain their unique spectrum of activity have included suggestions that they may interact with a variety of neurotransmitter systems. Recently, a possible interaction with the gamma-aminobutyric acid (GABA) system has received most attention. Benzodiazepines potentiate the actions of both synaptically released and exogenously administered GABA on mammalian neuronal preparations but the site of action within the GABA response mechanism has not been determined. Binding studies suggest that benzodiazepines combine with highly specific sites in the neuronal membrane and that these sites have some indirect association with GABA receptors. To investigate this association further in a functioning GABA system, quantitative studies have been made in vitro on neuronal depolarisations mediated by GABA receptor activation. Evidence has already been presented that bicuculline is most probably a competitive antagonist at the GABA receptor while picrotoxin acts as an antagonist at a separate site. Here flurazepam is shown to attenuate preferentially the action of picrotoxin rather than bicuculline and a model is suggested for the site of action of these drugs within the GABA response mechanism.     

3H-baclofen and 3H-GABA bind to bicuculline-insensitive GABA B sites in rat brain

The presence of a novel receptor for the neurotransmitter gamma-aminobutyric acid (GABA) on peripheral autonomic nerve terminals and in mammalian brain slices has been described recently. This receptor differs from the classical GABA site as it is unaffected by recognized GABA antagonists such as bicuculline and is not sensitive to the majority of accepted GABA-mimetics such as 3-aminopropanesulphonic acid (3-APS) or isoguvacine. We propose to designate the classical site as the GABA A and the novel site as the GABA B receptor. The beta-p-chlorophenyl derivative of GABA, baclofen, is stereospecifically active at the GABA B site whereas it is devoid of activity at the classical GABA A3 site. We now report that high-affinity saturable binding of 3H-baclofen and 3H-GABA to the GABA B site can be detected in fragments of crude synaptic membranes prepared from rat brain. The results support the concept of a novel GABA receptor within the mammalian brain and show that GABA and baclofen can compete for the same recognition site.