大鼠螺旋神经节神经元r-氨基丁酸A受体及N-甲基-D-天门冬氨酸受体亚单位的表达

目的：研究大鼠耳蜗螺旋神经节神经元A型γ-氨基丁酸受体（Gamma-aminobutyric acid receptor GABAAR）和N—甲基—D—天门冬氨酸受体(N-methyl D-aspartat receptor,NMDAR)亚单位的表达及意义。方法：原代培养大鼠螺旋神经节神经元,采用RT-PCR检测大鼠螺旋神经节神经元GABAAR和NMDAR亚单位的mRNA表达。 结果：大鼠螺旋神经节神经元mRNA表达GABAAR亚单位有α1-6,β1-3,γ1-3,且在α亚单位族中, α1,α3表达较高,差别无统计学意义（P>0.05）, α1,α3的表达量与其余亚单位表达量以及其余GABAAR亚单位之间表达量的差异有统计学意义（P<0.05）,各亚单位表达量大小排列顺序是:α1/α3＞α6＞α5＞α4＞α2。β亚单位族中,β亚单位族中各亚单位表达量两两比较差异有统计学意义,表达量排列顺序β1＞β3＞β2（P<0.05）;γ亚单位族中各亚单位表达量两两比较差别有统计学意义（P<0.05）,表达量排列顺序是γ2＞γ1＞γ3;NMDAR表达的亚单位有NR1,NR2A,NR2B,NR2C,NR2D,NR3A,NR3B,其中NR1亚单位的表达最高(P<0.05)。结论：大鼠螺旋节神经元mRNA上表达GABAAR的主要亚单位α1-6,β1-3,γ1-3和NMDAR NR1,NR2-D,NR3A-B亚单位.     

血小板活化因子对神经细胞内游离钙离子作用的研究

目的观察脑损害时病理活性介质血小板活化因子（ｐｌａｔｅｌｅｔａｃｔｉｖａｔｉｎｇｆａｃｔｏｒ,ＰＡＦ）及其拮抗剂对神经细胞内游离钙离子（［Ｃａ２＋］ｉ）浓度的影响,探讨ＰＡＦ致使神经细胞内［Ｃａ２＋］ｉ超载的途径及其作用机制。方法采用ＡＲＣＭＭＩＣ阳离子检测系统,观察不同浓度的ＰＡＦ以及其特异性受体拮抗剂ＢＮ５２０２１和非特异性拮抗剂ＭＫ８０１对体外培养１４天的大鼠皮层神经元［Ｃａ２＋］ｉ浓度的影响。结果５×１０－６ｍｏｌ／Ｌ的ＰＡＦ可使培养神经细胞［Ｃａ２＋］ｉ浓度明显增高,与对照组比较差异有显著意义（Ｐ＜０．０１）;ＢＮ５２０２１可明显阻止ＰＡＦ所致的神经细胞内［Ｃａ２＋］ｉ超载,在此基础上加用ＭＫ８０１可使神经细胞内［Ｃａ２＋］ｉ水平下降的更为明显。结论ＰＡＦ可通过多种渠道致使神经细胞内钙离子超载。     

血小板活化因子通过N-甲基-D-天(门)冬氨酸/突触后密度蛋白93途径致神经元损伤

目的探讨血小板活化因子(PAF)所致的神经元损伤是否涉及N-甲基-D-天(门)冬氨酸／突触后密度蛋白93(NMDA／PSD93)信号通路。方法细胞培养系统培养原代野生型和PSD93基因敲除型小鼠皮质神经元;0．3umol／LPAF处理神经元24h或5umol／LPAF受体拮抗剂(BN52021),10umol／L非竞争性NMDA受体拈抗剂(MK-801)和60umol／L神经性一氧化氮合成酶(nNOS)抑制剂(L—NAMA)预处理,碘化物／钙黄绿素染色检测细胞凋亡;免疫印迹检测野生型和基因敲除型小鼠皮质神经元中的多种蛋白表达;细胞免疫组化和共聚焦显微镜观察在同一神经轴突上共同表达多种蛋白;放免法测定神经元细胞蛋白中环鸟苷磷酸(cGMP)活性。结果(1)PSD93基因敲除型神经元不表达PSD93外,与野生型一样表达PSD93N-甲基-D-天(门)冬氨酸受体(NR2A)和nNOS。(2)神经轴突共同表达PSD93、NR2A和nNOS。(3)PSD93基因敲除型小鼠皮质神经元减少PAF对神经的毒性作用,并降低其cGMP活性。结论PAF通过NMDA／PSD93途径致神经细胞损伤。     

血小板活化因子乙酰水解酶基因突变与脑血管病的相关性研究

目的研究血小板活化因子(PAF)乙酰水解酶基因突变与中国人脑血管病(CVD)的关系.方法对153例脑血管病患者及100名健康对照者分别用多聚酶链式反应分析基因组DNA的突变等位基因,用Stafforini等的方法测定血浆PAF乙酰水解酶的活性.结果脑梗死组与脑出血组突变基因型及突变等位基因的频率显著高于对照组(P<0.01),不同危险因素间基因突变的差别无统计学意义.结论血浆PAF乙酰水解酶基因突变所致的酶缺乏可能是我国脑血管病的遗传学危险因素之一.     

红藻氨酸致痫大鼠海马神经元凋亡及其与caspase-3关系的研究

目的　研究大鼠癫痫发作后海马神经元凋亡及其与天冬氨酸特异性半胱氨酸蛋白酶 -3 (cysteinylasparate-specific proteinase,caspase-3 )表达的关系。方法　采用红藻氨酸 (kainic acid,KA)诱导大鼠癫痫模型 ,以原位末端标记 (TUNEL)及透射电镜检测癫痫发作后 6h及 1、3、7d海马神经元凋亡 ;半定量 RT-PCR及免疫组化法检测 caspase-3 m RNA及 caspase-3阳性表达。结果　KA致痫后 1 d,海马 CA1、CA3及 CA4区开始出现凋亡细胞 ,3 d时明显增多 ,7d时最多。 3个时间组相应区域间凋亡神经元数比较差异均有显著性 (P<0 .0 0 1 )。透射电镜观察可见典型的凋亡细胞形态学改变。 RT-PCR结果显示 ,KA致痫后 6h,海马组织 caspase-3 m RNA表达较对照组显著增高 (P <0 .0 5 ) ,1、3、7d caspase-3 m RNA仍持续高水平表达 (P <0 .0 5 )。免疫组化结果显示 ,KA致痫后 1 d,海马 CA1、CA3、CA4区开始出现 caspase-3阳性表达 ,3 d时阳性表达进一步增强 ,7d时表达最强。结论　凋亡参与 KA致痫大鼠癫痫发作后海马神经元迟发性死亡过程 ,caspase-3可能在癫痫后神经元凋亡过程中具重要的作用。     

脂多糖诱导的大鼠脑急性炎性损伤及血小板活化因子受体拮抗剂的干预治疗效果

目的研究脂多糖（1ipopolysaccharide,LPS）诱导的脑内炎性损害以及银杏内脂B（BN52021）的干预治疗效果。方法Sprague—Dawley大鼠30只,随机分为对照组,模型组和治疗组（BN52021治疗）,每组10只。第Ⅳ脑室注射LPS造模,Morris水迷宫检测实验动物学习和记忆能力;透射电子显微镜观察海马神经元突触数量及亚细胞结构的变化;免疫组织化学法检测脑内OX-42在小胶质细胞内的表达。结果治疗组大鼠的水迷宫逃避潜伏期比模型组显著缩短,平台象限游泳距离百分比显著增加;治疗组大鼠海马神经元内质网和核糖体数量比模型组明显增加,突触数量则无明显变化;治疗组大鼠脑内的OX-42阳性小胶质细胞数量比模型组明显减少,染色灰度上升。结论LPS可诱导脑内炎性损害,血小板活化因子受体拮抗剂BN52021对LPS诱导的脑内炎性损害具有保护作用,提示血小板活化因子受体拮抗剂对以中枢炎症为病理特征的神经退行性变有治疗作用。     

脂多糖诱导的大鼠脑急性炎性损伤及血小板活化因子受体拮抗剂的干预治疗效果(英文)

目的研究脂多糖(lipopolysaccharide,LPS)诱导的脑内炎性损害以及银杏内脂B(BN52021)的干预治疗效果。方法Sprague-Dawley大鼠30只,随机分为对照组,模型组和治疗组(BN52021治疗),每组10只。第Ⅳ脑室注射LPS造模,Morris水迷宫检测实验动物学习和记忆能力;透射电了显微镜观察海马神经元突触数量及亚细胞结构的变化;免疫组织化学法检测脑内OX-42在小胶质细胞内的表达。结果治疗组大鼠的水迷宫逃避潜伏期比模型组显著缩短,平台象限游泳距离百分比显著增加;治疗组大鼠海马神经元内质网和核糖体数量比模型组明显增加,突触数量则无明显变化;治疗组大鼠脑内的OX-42阳性小胶质细胞数量比模型组明显减少,染色灰度上升。结论LPS可诱导脑内炎性损害,血小板活化因子受体拮抗剂BN52021对LPS诱导的脑内炎性损害具有保护作用,提示血小板活化因子受体拮抗剂对以中枢炎症为病理特征的神经退行性变有治疗作用。     

血小板活化因子乙酰水解酶基因突变(Val279-Phe)与急性脑出血的相关性研究

目的　探讨血小板活化因子乙酰水解酶基因突变 (Val2 79-Phe)与急性脑出血的关系。方法　对 10 2例急性脑出血患者、174例原发性高血压患者及 2 2 5例健康对照者 ,分别用多聚酶链式反应分析基因组DNA的突变等位基因 ,用Stafforini等的方法测定血浆PAF乙酰水解酶的活性。结果　脑出血组突变的发生率 (4 7.1% )显著高于对照组 (P <0 .0 1)。高血压组突变的发生率(32 .7% )与对照组 (2 4 .4 % )之间无显著差异 (P >0 .0 5 )。结论　血浆中血小板活化因子乙酰水解酶基因突变所致的酶缺乏可能是急性脑出血的独立危险因素。     

抑制p38 MAPK信号通路对海马神经元毒性损伤的保护作用

目的通过观察细胞表面形态的三维构像变化,探讨抑制p38 MAPK通路对减轻红藻氨酸(KA)毒性作用引起大鼠海马神经元所造成损害的作用和机制。方法原代培养10 d的海马神经元给予SB203580(0.2μmol/L),p38MAPK特异性抑制剂)预处理.30min后再予不同浓度(0μmol/L,25μmol/L和250μmol/L)KA分别作用10 min和100 min,利用原子力显微镜(AFM)对细胞表面结构进行纳米级水平扫描和观测。结果正常海马神经元表面光滑,起伏均匀、规律;KA作用后神经元呈退行性改变,表现为胞体肿胀,胞膜表面粗糙,出现隆起和“孔洞”样胞膜破裂结构,并且其变化程度分别与作用时间和KA浓度呈量-效关系;预先给予SB203580处理,以上变化有所减轻。结论KA毒性作用后海马神经元胞膜表面超微结构所产生明显变化;p38MAPK信号通路参与这种损害过程;抑制该信号转导通路,对海马神经元的毒性损害起一定保护作用。     

血小板活化因子乙酰水解酶基因多态性V279F与缺血性卒中易感性及复发的相关性研究

目的  评价血小板活化因子（platelet-activating factor,PAF）乙酰水解酶（acetylhydrolase,AH）基因多态性位点V279F与缺血性卒中易感性及复发的关系。 方法  本研究连续选取2008年11月～2014年11月山东省潍坊市人民医院神经内科住院的386首发急性TOAST分型[5]中大动脉粥样硬化（large-artery atherosclerosis,LAA）性卒中和小动脉闭塞（small-artery occlusion,SAO）性卒中患者共386例为试验组和386例健康体检者,作为对照组,采用酶联免疫吸附法（enzyme linked immunosorbent assay,ELISA）测定血清PAF-AH浓度,聚合酶链反应（polymerase chain reaction,PCR）及基因直接测序法测定V279F基因位点多态性,对缺血性卒中患者平均随访4.5年,通过多元生存分析,探讨基因多态性与缺血性卒中复发的相关性。 结果  缺血性卒中患者血清PAF-AH浓度［（4.78±1.28）μg/L］高于对照组［（4.11±1.34）μg/L］,V279F位点中FF+VF基因型频率（44.6%）,VF基因型频率（28.8%）和F等位基因频率（16.5%）在缺血性卒中组及LAA性卒中组均高于对照组（30.4%,22.3%,12.2%）,差异有显著性（P=0.023,P=0.031,P=0.022）。卒中亚组分析显示V279F多态性与LAA性卒中相关性更强。随访结果提示,25.8%患者缺血性卒中复发,将高血压、糖尿病、高血脂、吸烟史、既往短暂性脑缺血发作病史及基因型分布进行多元回归分析显示,VF+FF基因型与缺血性卒中及LAA性卒中复发相关［风险比（hazard ratio,HR）1.75,95%可信区间（confidence interval,CI）1.03～2.29,P=0.041;HR?1.84,95%CI?1.13～2.41,P=0.037）］。 结论  缺血性卒中患者Lp-pla2水平升高,LAA性卒中升高最明显;V279F基因多态性可能与LAA性卒中的易感性相关,与缺血性卒中及LAA性卒中复发相关。     

Recombinant plasma-type platelet-activating factor acetylhydrolase attenuates NMDA-induced hippocampal neuronal apoptosis

The bioactive lipid platelet-activating factor (PAF) accumulates in brain during injury, seizures and ischemia and may, in addition, be significant in AIDS dementia and in other neurodegenerative diseases. We have used plasma-type recombinant PAF acetylhydrolase (rPAF-AH) to test the hypothesis that PAF accumulation is involved in early events leading to neuronal apoptosis during excitotoxic neuronal injury. Neuronal cultures were labeled with FITC-12-dUTP (TUNEL technique) and propidium iodide, digitized using fluorescence microscopy and a chilled 3CCD color camera, and analyzed with 2D graphics analysis software. N-methyl-D-aspartate (NMDA) (50 μM, 2 hr) induced a 2.5-fold increase in apoptosis of hippocampal neurons compared with controls when analyzed 24 hr after NMDA treatment. Hippocampal neurons receiving rPAF-AH (20 μg/ml) before, during, and after NMDA treatment demonstrated a concentration-dependent neuroprotective effect which resulted in 47% and 30% neuroprotection against 50 and 100 μM NMDA, respectively. The noncompetitive NMDA receptor antagonist MK-801(300 nM) completely inhibited apoptosis caused by NMDA. The neuroprotective effect of rPAF-AH against NMDA-induced apoptosis was confirmed using as additional criteria, histone release, electron microscopy, and DNA laddering. Neuroprotection elicited by rPAF-AH demonstrates that PAF is an injury mediator in NMDA-induced neuronal apoptosis and that the recombinant protein is potentially useful as a therapeutic approach. J. Neurosci. Res. 53:677–684, 1998. © 1998 Wiley-Liss, Inc.     

Involvement of the NMDA receptor/nitric oxide signal pathway in platelet-activating factor-induced neurotoxicity

Platelet-activating factor (PAF), a bioactive phospholipid implicated in neuronal excitotoxic death, augments the presynaptic release of glutamate. Excessive activation of postsynaptic glutamate receptors and subsequent downstream signals leads to excitotoxicity. The present study proposed that the NMDA receptor/nitric oxide (NO) signal pathway might be involved in PAF-induced neurotoxicity. After the cultured neurons were exposed to PAF for 24 h the percentage of neuronal death increased in a dose-dependent manner. The PAF effects were significantly prevented not only by BN52021, a PAF antagonist, but also by MK-801, an NMDA antagonist, and L-NAME, an NO synthase (NOS) inhibitor. Moreover, the increases in NOS activity and neuronal NOS expression induced by chronic exposure of the cultured neurons to PAF were dramatically blocked by BN52021 and MK-801, respectively. Our findings suggest that the NMDA receptor/NO signaling pathway might contribute to the pathological mechanism of cell death triggered via PAF receptor activation.     

Aluminum-induced apoptosis in cultured cortical neurons and its effect on SAPK/JNK signal transduction pathway

Aluminum exposure and apoptotic cell death has been implicated in several neurodegenerative diseases. The mechanisms by which aluminum interacts with the nervous system are only partly understood. In this study, we used cultured cortical neurons to investigate the ability of aluminum to induce the apoptosis of neurons and to explore the role of SAPK/JNK (stress-activated protein kinase or c-jun N-terminal kinase) signal transduction pathway on the apoptosis induced by aluminum. We found that aluminum-induced degeneration of cortical neurons involved the DNA fragmentation characteristic of apoptosis, and staining of aluminum-treated neurons with the DNA-binding fluorochrome Hoechst 33258 revealed the typical apoptotic condensation and fragmentation of chromatin. The rate of apoptosis increased significantly (from 4.9 to 13.1, 21.4, and 59.8%, P<0.01), which was measured by TdT-mediated dUTP nick end labeling. Western blot analysis showed that SAPK/JNK activities of cortical neurons varies when the exposure time of AlCl(3) were different. The phosphorylation levels were 4.2, 3.3, 1.9 and 1.1 times greater compared to control cultures for 6, 12, 24, and 48 h, respectively (P<0.01). Furthermore, a JNK pathway inhibitor, CEP-11004 (KT8138) inhibited the activation of SAPK/JNK to protect cortical neurons from apoptosis induced by aluminum chloride. Our study demonstrates that aluminum can induce the apoptosis of cortical neurons and SAPK/JNK signal transduction pathway may play an important role in the apoptosis.     

Synergistic effects of platelet-activating factor and other platelet agonists in human platelet aggregation and release: The role of adp and products of the cyclooxygenase pathway

The synergistic effects of platelet-activating factor (PAF) with ADP, collagen, thrombin, A23187, adrenaline, sodium arachidonate and ristocetin in human platelet aggregation and ß-thromboglobulin (ß-TG) release were investigated in citrated platelet-rich plasma (PRP). Synergism in both aggregation and release was present with all agonists except ristocetin.Upon oral intake of aspirin (ASA) the PAF-induced irreversible aggregation as well as the synergistic irreversible aggregation became reversible. Both prior to and after ASA ingestion ADP removal by creatine phosphate/creatine phosphokinase (CP/CPK) resulted in a reduced, reversible platelet aggregation induced by PAF alone or in combination with the other agonists. The ADP-removal and ASA-ingestion also strongly inhibited the ß-TG release. The synergistic aggregation and release were also inhibited by ASA and indomethacin in vitro as well as by the competitive ADP-inhibitor ATP.It is concluded that not only the activation of human platelets by low doses of PAF itself, but also the synergism of PAF and other platelet agonists is highly dependent upon ADP and products of the cyclooxygenase pathway.     

Human and rabbit platelets form platelet-activating factor in response to calcium ionophore

Homogenous preparations of human and rabbit platelets synthesized platelet-activating factor (PAF) when stimulated by calcium ionophore A23187. PAF was isolated by high performance liquid chromatography (HPLC) on a Lichrosorb Si60 column. PAF was well separated from other phospholipids especially sphingomyelin and lysolecithin. The retention times of PAF derived from human or rabbit platelets were identical to the commercially available semisynthetic PAF and radiolabeled PAF. The amount of PAF was determined by the extent to which it induced the aggregation of washed rabbit platelets.     

Targeted disruption of PSD-93 gene reduces platelet-activating factor-induced neurotoxicity in cultured cortical neurons

PSD-93, a molecular adaptive protein, binds to and clusters the N-methyl-D-aspartate (NMDA) receptor and assembles a specific set of signaling proteins (for example neuronal nitric oxide synthase, nNOS) around the NMDA receptor at synapses in the central nervous system. This suggests that PSD-93 might mediate many NMDA receptor-dependent physiological and pathophysiological functions. We report here that PSD-93 colocalizes and interacts with the NMDA receptor and neuronal nitric oxide synthase in cultured cortical neurons. Targeted disruption of PSD-93 gene significantly prevented NMDA receptor-nitric oxide signaling-dependent neurotoxicity triggered via platelet-activating factor (PAF) receptor activation. In addition, the deficiency of PSD-93 markedly attenuated platelet-activating factor-induced increase in cyclic guanosine 3',5'-monophosphate (cGMP) and prevented platelet-activating factor-promoted formation of NMDA receptor-neuronal nitric oxide synthase complex. These findings indicate that PSD-93 is involved in the NMDA receptor--nitric oxide-mediated pathological processing of neuronal damage triggered via platelet--activating factor receptor activation. Since platelet-activating factor is a potent neuronal injury mediator during the development of brain trauma, seizures, and ischemia, the present work suggests that PSD-93 might contribute to molecular mechanisms of neuronal damage in these brain disorders.     

Chronic hyperammonemia impairs the glutamate–nitric oxide–cyclic GMP pathway in cerebellar neurons in culture and in the rat in vivo

The aim of this work was to assess whether ammonia concentrations similar to the increase found in the brain of hyperammonemic rats (100 μm ), impair N-methyl-d -aspartate (NMDA) receptor-mediated signal transduction. We first measured glutamate neurotoxicity, which in these neurons is mediated by activation of NMDA receptors, as an initial parameter reflecting activation of NMDA receptor-mediated pathways. Long-term treatment of cultured neurons with ammonia prevents glutamate-induced neuronal death. The EC₅₀ was 20 μm , and at 100 μm the protection was complete. The induction of the protective effect was not immediate, but took several hours. Treatment with 100 μm ammonia did not prevent a glutamate- or NMDA-induced rise of intracellular calcium. Ammonia impaired the glutamate–nitric oxide–cGMP (3′,5′-cyclic guanosine monophosphate) pathway in a dose- and time-dependent manner. Glutamate-induced formation of cGMP was reduced by 42%, while activation of nitric oxide synthase was not affected. Ammonia reduced by 31% cGMP formation induced by S-nitroso-N-acetyl-penicillamine (SNAP), a NO-generating agent, confirming that the interference occurs at the level of guanylate cyclase activation by nitric oxide. To assess whether chronic moderate hyperammonemia in vivo also impairs the glutamate–nitric oxide–cGMP pathway, we determined by in vivo brain microdialysis in freely moving rats the formation of cGMP induced by NMDA. In hyperammonemic rats, the formation of cGMP induced by NMDA and SNAP was reduced by ca. 60 and 41%, respectively, indicating that chronic hyperammonemia in the animal in vivo also impairs the glutamate–nitric oxide–cGMP pathway. Impairment of this pathway can contribute to the neurological alterations found in hyperammonemia and hepatic encephalopathy.     

A DAP12‐Dependent signal promotes pro‐inflammatory polarization in microglia following nerve injury and exacerbates degeneration of injured neurons

Under pathological conditions, activated microglia play paradoxical roles and could have neurotoxic or neuroprotective effects. However, the signal determining how activated microglia affects the fate of neuronal cells remains largely unknown. Here we demonstrate that DNAX‐activating protein of 12 kDa (DAP12), a transmembrane adaptor protein that contains an immunoreceptor tyrosine‐based activation motif, is a critical regulator of microglial function after nerve injury. In a model of mouse hypoglossal nerve injury, the duration of microglial increase after nerve injury became shorter in mice lacking DAP12, although microglial morphology and total cell numbers were not significantly affected during early phase after nerve injury. Intriguingly, expressions of M1‐phenotype markers including pro‐inflammatory cytokines were suppressed in DAP12‐deficient microglia. Furthermore, axotomy‐induced motor neuron death was markedly prevented in DAP12‐deficient mice. Collectively, DAP12‐mediated microglial activation following axotomy promotes pro‐inflammatory responses, and thereby accelerates nerve injury‐induced neuron death, suggesting that DAP12 is a potential therapeutic target for the protection of neuronal degeneration caused by microglial activation. GLIA 2015;63:1073–1082     

脑源性神经营养因子对海马神经元NMDA受体功能下调的逆转作用

应用全细胞膜片钳技术研究BDNF对培养养海马神经元NMDA受体的调控作用。结果发现,培养18d的海马神经元NMDA诱发电流小,BDNF可快速、可逆地增加NMDA诱发电流,而培养10,14d的海马神经元NMDA诱发电流大,BDNF增强NMDA诱发电流不明显。本文结果提示BDNF对功能低下的海马神经元NMDA受体具有上调作用。