丹酚酸B对β-淀粉样蛋白介导原代培养皮层神经元毒性的保护作用

目的　观察一氧化氮(NO)在谷氨酸(Glu),β-淀粉样蛋白［β-AP(1-40)］引起神经细胞损伤中的作用以及丹酚酸B(Sal B)对β-AP(1-40)引起的神经细胞损伤保护作用。方法　原代培养大鼠皮层神经元,建立了硝普钠(SNP),Glu,β-AP(1-40)等3种损伤模型,用形态学观察、MTT比色法、Griess法分别测定神经元活力,培养液中乳酸脱氢酶(LDH)漏出和NO释放。结果　Glu和β-AP(1-40)可以引起神经元NO的释放增加,造成神经毒性。nNOS在Glu的毒性中起重要作用,iNOS可能在Aβ_1-40的毒性中起作用。Sal B能显著增加细胞活力,降低LDH释放率,并剂量依赖地减少NO释放。 结论　NO介导了Glu和β-AP(1-40)的毒性,Sal B可以通过减少NO释放,改善β-AP(1-40)的毒性作用。     

灯盏花素对谷氨酸诱导大鼠海马神经细胞毒性的保护作用

选用培养的海马神经细胞研究灯盏花素(breviscapine，Bre)对谷氨酸(glutamate，Glu)诱导神经细胞毒性的保护作用及其机制。新生大鼠海马神经细胞体外培养8 d后， 用L-谷氨酸(0.1， 0.5及1.0 mmol·L^-1)处理30 min； 灯盏花素处理组在加入L-谷氨酸的同时给予不同剂量的灯盏花素(10， 20及40 μmol·L^-1)； 继续正常培养24 h后， 用Annexin V联合流式细胞仪检测细胞的凋亡和坏死率； RT-PCR分析凋亡蛋白抑制剂XIAP mRNA的表达。结果表明， L-谷氨酸浓度依赖性地诱导神经细胞发生凋亡和坏死， 并使细胞XIAP mRNA表达发生浓度依赖性的双向变化： 0.1 mmol·L^-1 L-谷氨酸使神经细胞XIAP mRNA表达增强， 而较高浓度使XIAP mRNA表达下调。灯盏花素(20和40 μmol·L^-1)可有效抑制谷氨酸诱导的神经细胞死亡， 分别使细胞凋亡率下降30.4%和40.1%， 坏死率下降32.5%和38.8%； 并上调XIAP mRNA表达45.1%和54.9%。激光共聚焦显微技术联合Fluo-3荧光标记检测表明，L-谷氨酸处理过程中海马神经细胞内Ca²⁺水平显著升高， 而灯盏花素可抑制谷氨酸引起的细胞内Ca²⁺超载(P<0.01)。以上结果提示， 灯盏花素可能通过抑制细胞Ca²⁺超载， 调节凋亡抑制因子XIAP的表达而有效保护谷氨酸对神经细胞的兴奋性毒性作用。     

银杏叶提取物对谷氨酸诱导神经细胞损伤的作用研究

目的：探究银杏叶提取物（EGb）对谷氨酸诱导体外培养神经细胞损伤的保护作用及相关机制,为EGb应用于缺血性卒中提供依据。方法：取孕15～18天SD胎鼠的皮层神经细胞进行原代培养（对照组）,在此基础上,建立谷氨酸诱导神经细胞损伤模型（Glu组）。向Glu组中预先加入4种不同浓度（12．5～100mg&#183;L^-1）EGb作用（研究组）。通过测定神经细胞NO及LDH的释放量来反映神经细胞损伤程度。结果：谷氨酸呈浓度依赖性升高神经细胞NO及LDH释放量;与Glu组相比较,EGb（12．5～100mg&#183;L^-1）能不同程度的抑制NO、LDI-I释放,且EGb浓度为50mg&#183;L^-1时作用最显著（P〈0．01）。结论：谷氨酸通过NO诱导神经细胞损伤,EGb通过抑制NO、LDH释放实现拮抗谷氨酸神经细胞毒性作用。     

丁基苯酞对低糖低氧诱导的大鼠皮层神经细胞损伤的保护作用

为进一步探讨丁基苯肽对神经的保护作用,用原代培养大鼠皮层神经细胞的方法,以LDH和细胞形态等指标,观察了l-丁基苯酞(l-NBP)和d-丁基苯酞(d-NBP)对低糖低氧诱导的大鼠皮层神经细胞损伤的保护作用。结果表明:l-NBP和d-NBP能剂量依赖性地抑制低糖低氧诱导的大鼠皮层神经细胞内LDH的释放,降低细胞死亡率,并能改善受损细胞的形态;此外还能明显减轻低糖低氧诱导的神经细胞内粗面内质网脱颗粒及多聚核糖体解聚。提示:NBP对低糖低氧诱导的大鼠皮层神经细胞损伤有明显保护作用。     

丹酚酸B对β-淀粉样蛋白介导原代培养皮层神经元毒性的保护作用

目的　观察一氧化氮 (NO)在谷氨酸 (Glu) ,β 淀粉样蛋白 [β AP(1 40 ) ]引起神经细胞损伤中的作用以及丹酚酸B(SalB)对 β AP(1 40 )引起的神经细胞损伤保护作用。 方法　原代培养大鼠皮层神经元 ,建立了硝普钠(SNP) ,Glu ,β AP(1 40 )等 3种损伤模型 ,用形态学观察、MTT比色法、Griess法分别测定神经元活力 ,培养液中乳酸脱氢酶 (LDH)漏出和NO释放。结果　Glu和 β AP(1 40 )可以引起神经元NO的释放增加 ,造成神经毒性。nNOS在Glu的毒性中起重要作用 ,iNOS可能在Aβ1 4 0 的毒性中起作用。SalB能显著增加细胞活力 ,降低LDH释放率 ,并剂量依赖地减少NO释放。结论　NO介导了Glu和 β AP(1 40 )的毒性 ,SalB可以通过减少NO释放 ,改善 β AP(1 40 )的毒性作用。     

丁基苯酞对原代培养胎大鼠皮层神经细胞外液NO及胞浆内cGMP水平的影响

用分光光度法和放射免疫分析法分别检测NO及cGMP水平,同时观察l-丁基苯酞(l-NBP)和d-丁基苯酞(d-NBP)对原代培养的胎大鼠皮层神经细胞外液NO及胞浆内cGMP水平的影响。结果表明,d-NBP(0.1～100μmol·L^-1)对低糖低氧条件下或含N-甲基-D-门冬氨酸(NMDA)或含KCl的培养基中皮层神经细胞外液NO及细胞内cGMP水平明显升高,而l-NBP(0.1～100μmol·L^-1)则能明显降低NO和cGMP水平。提示:d-NBP和l-NBP对低糖低氧,NMDA或KCl诱导的NO释放和cGMP生成有相反的作用。     

氯丙嗪对谷氨酸诱导大鼠脑皮质受损神经细胞的保护作用

目的:观察氯丙嗪(CPZ)对谷氨酸(Glu)诱导的大鼠大脑皮质神经细胞兴奋毒性的影响.方法:用倒置显微镜观察神经细胞形态的变化,用Trypan blue染色法观察细胞生存率,测定乳酸脱氢酶(LDH)以定量反映细胞损伤程度.结果:50 μmol&#8226;L 1Glu使神经细胞死亡率升高,LDH释放增加351%;1,10 μmol&#8226;L 1CPZ能改善神经细胞生长,降低细胞死亡率,减少LDH的释放.结论:CPZ可明显抑制Glu介导的神经毒性作用.     

内源性一氧化氮介导脂质胞壁酸预适应对人冠脉内皮细胞再复氧损伤的作用

目的探讨脂质胞壁酸(LTA)诱导的延迟预适应对内皮细胞再复氧(H/R)损伤的作用，以及内源性一氧化氮(NO)参与保护机制的作用。方法采用培养的人冠状动脉内皮细胞(HCAECs)在缺氧条件下培养2 h，然后在常氧条件下复氧培养4 h，模拟缺血/再灌注损伤的模型。HCAECs在缺氧前24 h预先在含LTA(30或300 μg·L^-1)的培养基中培养4 h。用台盼蓝排斥法和培养基中乳酸脱氢酶(LDH)含量来评价内皮细胞损伤程度，比色法检测培养基中一氧化氮(NO)含量。并用RT-PCR检测LTA预适应后(2-24) h HCAECs eNOS mRNA的表达。结果LTA预适应能显著减少台盼蓝排斥实验中的细胞死亡百分比，降低复氧末细胞培养液中LDH的含量。LTA预适应亦能显著增加HCAECs复氧末培养液中NO含量。LTA预适应的效应可被非选择性NOS抑制剂L-单甲基精氨酸(L-NMMA,100 μmol·L^-1)所取消。在LTA预适应后2和4 h，HCAECs的eNOS mRNA表达明显增加。结论 LTA诱导的延迟预适应能显著减少HCAECs 再复氧所致的细胞损伤和功能紊乱，eNOS产生的NO启动并介导了LTA保护内皮细胞的作用。     

皮质酮对原代培养大鼠海马神经细胞的毒性作用及其与兴奋性氨基酸的关系

探讨了皮质酮对原代培养海马神经细胞的毒性作用及作用机理. 结果显示,无血清培养基中加入皮质酮（10 nmol·L^-1-0.1 mmol·L^-1）可浓度依赖地损伤原代培养的海马和皮层神经细胞,其EC₅₀分别为3.2 和85 μmol·L^-1. 预先加入N-甲基-D-天冬氨酸(NMDA)受体拮抗剂地佐环平(MK 801,终浓度为50 μmol·L^-1）可显著拮抗皮质酮（10 μmol·L^-1）对海马神经细胞的毒性作用. 皮质酮同海马脑薄片共同孵育10和20 min可明显增加海马脑薄片谷氨酸和谷氨酰胺的释放,对天冬氨酸的释放则无明显影响. 实验结果提示,皮质酮可选择性地损伤原代培养海马神经细胞,该毒性作用可能与其增加兴奋性氨基酸释放有关.     

6-羟基多巴的细胞毒作用与谷氨酸转运的关系

目的探讨6-羟基多巴(6-OHDA)导致细胞毒性与谷氨酸(glutamate,Glu)递质水平和谷氨酸转运体的相关性。方法大鼠脑黑质内定位注射6-OHDA,制备帕金森病(Parkinson's disease,PD)动物模型;用在体微透析技术收集大鼠纹状体细胞外液;用高效液相色谱法测定PD大鼠纹状体和PC12细胞的细胞外液中Glu的水平;用流式细胞仪和酶标仪检测细胞凋亡率和细胞活性;通过测定L-［³H］-Glu的摄取能力确定谷氨酸转运体的功能。结果6-OHDA诱导PC12细胞和大鼠损毁侧纹状体释放Glu增加,使PC12细胞凋亡和活性降低,而PC12细胞和突触体上的谷氨酸转运体功能显著下降。结论6-OHDA引起的神经毒性与其增加Glu释放和降低谷氨酸转运体功能有关。     

Serofendic acid prevents acute glutamate neurotoxicity in cultured cortical neurons

We have previously reported that a novel neuroprotective substance named serofendic acid was purified and isolated from ether extract of fetal calf serum. In the present study, we investigated the effect of serofendic acid on acute neurotoxicity induced by L-glutamate (Glu) using primary cultures of rat cortical neurons. Exposure of cortical cultures to Glu for 1 h caused a marked decrease in cell viability, as determined by trypan blue exclusion. This acute Glu neurotoxicity was prevented by N-methyl-D-aspartate (NMDA) receptor antagonists, extracellular Ca(2+) removal, nitric oxide (NO) synthase inhibitor and NO scavenger. Serofendic acid prevented acute Glu neurotoxicity in a concentration-dependent manner. Acute neurotoxicity was induced by ionomycin, a Ca(2+) ionophore, and S-nitroso-L-cysteine, an NO donor. Serofendic acid also prevented both ionomycin- and S-nitroso-L-cysteine-induced neurotoxicity. Moreover, the protective effect of serofendic acid on acute Glu neurotoxicity was not affected by cycloheximide, a protein synthesis inhibitor, and actinomycin D, an RNA synthesis inhibitor. These results indicate that serofendic acid protects cultured cortical neurons from acute Glu neurotoxicity by reducing the cytotoxic action of NO and de novo protein synthesis is not required for this neuroprotection.     

褪黑素对大脑皮层细胞一氧化氮含量及其神经毒性作用的影响

目的：探讨褪黑素(MT)抗衰老作用与神经细胞NO释放之间的联系。方法：连续给予老年小鼠MT，检测大脑皮层神经细胞NO含量的变化,并用原代培养的大鼠皮层神经元，去血清培养后，观察MT对高钾、谷氨酸（Glu）诱发NO释放及硝普钠（SNP）致神经毒性作用的影响。结果：MT能明显抑制老年小鼠脑内NO含量的增高，并拮抗KCI与Glu诱发的NO释放及SNP引起的神经毒性，对大脑神经元有保护作用。结论：MT抑制大脑皮层NO含量增高，可能是其抗衰老作用的机制之一。     

Preventing Extracellular Diffusion of Trigeminal Nitric Oxide Enhances Formalin-induced Orofacial Pain

Nitric oxide (NO), a diffusible gas, is produced in the central nervous system, including the spinal cord dorsal horn and the trigeminal nucleus, the first central areas processing nociceptive information from periphery. In the spinal cord, it has been demonstrated that NO acts as pronociceptive or antinociceptive mediators, apparently in a concentration-dependent manner. However, the central role of NO in the trigeminal nucleus remains uncertain in support of processing the orofacial nociception. Thus, we here investigated the central role of NO in formalin (3%)-induced orofacial pain in rats by administering membrane-permeable or -impermeable inhibitors, relating to the NO signaling pathways, into intracisternal space. The intracisternal pretreatments with the NO synthase inhibitor L-NAME, the NO-sensitive guanylate cyclase inhibitor ODQ, and the protein kinase C inhibitor GF109203X, all of which are permeable to the cell membrane, significantly reduced the formalin-induced pain, whereas the membrane-impermeable NO scavenger PTIO significantly enhanced it, compared to vehicle controls. These data suggest that an overall effect of NO production in the trigeminal nucleus is pronociceptive, but NO extracellularly diffused out of its producing neurons would have an antinociceptive action.     

Inhibition of nitric oxide synthesis accelerates the recovery of polysynapitc reflex potentials after transient spinal cord ischemia in cats

Nitric Oxide (NO) has been implicated as a mediator of neuronal injury in vascular stroke. On the other hand, NO is suggested to play a neuroprotective role by increasing blood flow during cerebral ischemia. In order to evaluate the role of NO in the spinal cord ischemia, effects of nitric oxide synthase (NOS) inhibition on the recovery of reflex potentials after a transient spinal cord ischemia were examined in urethane-chloralose anesthetized spinal cats. Spinal cord ischemia was produced by occlusion of the thoracic aorta and the both internal mammary arteries for 10min. Regional blood flow (RBF) in the spinal cord was continuously measured with a laser-Doppler flow meter. The monosynaptic (MSR) and polysynaptic reflex (PSR) potentials elicited by electrical stimulation of the tibial nerve, were recorded from the L7 or S1 ventral root. The recovery process of spinal reflex potentials was reproducible when the oclusion was repeated twice at an interval of 120min. Pretreatment with N ^G-monomethyl-l-arginine (l-NMMA, 10mg/kg), a NOS inhibitor significantly accelerated the recovery of PSR potentials after spinal cord ischemia. The accelerating effect of l-NMMA on the recovery of PSR potentials was abolished by co-administration of l-arginine (1mg/kg/min) but not by that of d-arginine (1mg/kg/min). l-NMMA failed to improve RBF in the spinal cord during ischemia and reperfusion. Nitroprusside (10μg/kg/min), a NO donor, retarded the recovery of PSR potentials after spinal cord ischemia. These results suggest that NO production has a significant influence on the functional recovery after transient spinal cord ischemia. Received: 16 September 1996/Accepted: 2 January 1997     

Involvement of spinal nitric oxide (NO) in rat pain-related behaviors induced by the venom of scorpion Buthus martensi Karsch

In the present study, we investigated the role of spinal nitric oxide (NO) in rat pain-related behaviors induced by the venom of scorpion Buthus martensi Karsch (BmK). The results showed that the number of neuronal NO synthase (nNOS) positive neurons significantly increased in superficial (I-II), deep (V-VI) dorsal horn laminae and the ventral gray laminae (VII-X), but not in the nucleus proprius (III and IV) of bilateral L4-L5 lumbar spinal cord after unilateral intraplantar injection of BmK venom from 2h to 7d. This increase on the ipsilateral side to BmK venom injection was always greater than that on the contralateral side. Western blotting analysis confirmed that spinal nNOS expression was significantly up-regulated following BmK venom administration. In addition, intrathecal delivery of N(omega)-nitro-l-arginine methyl ester hydrochloride (l-NAME; a NOS inhibitor) before intraplantar injection of BmK venom by 10 min significantly attenuated spontaneous nociceptive responses and prevented the development of primary thermal hyperalgesia as well as bilateral mechanical hyperalgesia. Intrathecal injection of l-NAME could also partially inhibit BmK venom-induced c-Fos expression in lumbar spinal cord at 2 h. Thus, the results suggest that spinal NO as a critical mediator is involved in various pain-related behaviors and c-Fos expression induced by BmK venom in rats.     

神经生长因子对一氧化氮介导的大鼠脑皮质神经元毒性的影响

研究神经生长因子（ＮＧＦ）对一氧化氮（ＮＯ）介导的大鼠脑皮质神经无毒性的影响。方法：用原代培养的大鼠胎鼠脑皮质神经细胞，测定ＮＯ含量及原生型一氧化氮合酶（ｃＮＯＳ）基因表达，并研究ＮＧＦ对细胞缺氧／缺糖损伤的影响。结果：细胞缺氧／缺糖培养 ２４ ｈ后，细胞死亡率明显增高，ＮＯ大量释放。 ＮＧＦ １００ μｇ／Ｌ显著提高细胞生存力，降低ＮＯ释放，但其对硝普钠（ＳＮＰ）３００ μｍｏｌ／Ｌ引起的ＮＯ大量释放及细胞死亡率升高无明显影响。 ＮＧＦ５０、１００ μｇ／Ｌ显著降低细胞缺氧／缺糖引起的 ｃＮＯＳ ｍＲＮＡ的高表达。结论：ＮＯ介导了细胞缺氧／缺糖损伤，ＮＧＦ通过抑制ｃＮＯＳ活性，降低ＮＯ释放来保护神经元免受缺氧／缺糖损伤。     

Vanadate-induced nitric oxide production: role in osteoblast growth and differentiation

Nitric oxide (NO) has been shown to act as a mediator of cytokines in bone tissue. We have previously demonstrated that vanadium compounds are insulin- and growth factor-mimetic compounds in osteoblasts in culture, although high doses are toxic to these cells. In this study, we measured NO production in two osteoblast-like cells (UMR106 and MC3T3E1) incubated with different concentrations (2.5–100 μM) of vanadate. Vanadate induced NO release in a biphasic manner, with levels being significantly increased at concentrations over 50 μM. The NO donor, sodium nitroprusside, mimicked the vanadate effect: it inhibited cell growth and alkaline phosphatase activity in a dose-dependent manner. Vanadate enhanced the NO synthases, the endothelial and inducible (eNOS and iNOS) isoforms, in a dose-dependent manner. Experiments performed with the ionophore A23187 and EGTA suggested that vanadate-induced NO production involves Ca²⁺-dependent and -independent mechanisms. Altogether, our results suggest that NO may play a critical role in the bioactivity of vanadium in osteoblast-like cells.     

Different roles of two nitric oxide activated pathways in spinal long-term potentiation of C-fiber-evoked field potentials

There is accumulating evidence implicating the involvement of nitric oxide (NO) in spinal central sensitization. The long-term potentiation (LTP) of spinal C-fiber-evoked field potentials is considered as a fundamental mechanism of sensitization of nociceptive neurons in the spinal cord. The present study examined the roles of soluble guanylate cyclase (sGC) or ADP-ribosyltransferase (ADPRT), two potential NO targets, in spinal LTP. The results showed that (1) administration of sGC inhibitors, methyl blue (MB, 4mM, 20 microl) or 1H-[1,2,4]oxadiazolo[4,3-a]-quiloxalin-1-one (ODQ, 10 microM, 20 microl) before tetanic stimulation, significantly inhibited the induction of spinal LTP, and this was reversed by 8-Br-cGMP, a membrane-permeable cGMP analog. However, the maintenance of spinal LTP was not changed when application of ODQ 2h after tetanic stimulation. (2) Although our previous experiments have identified a key role for NO in the induction of spinal LTP, NO synthase (NOS) inhibitor, L-NAME (1mM, 20 microl) or hemoglobin (2mg/ml, 20 microl), a scavenger of NO, had no effect on established spinal LTP when applied 2h after the induction of spinal LTP. (3) The mono-ADPRT inhibitor, nicotinamide (10mM, 20 microl), had no effect on the induction and maintenance of spinal LTP. However, the poly-ADPRT inhibitor, benzamide (100 microM, 20 microl), inhibited its maintenance, but not its induction. The results suggest that NO-stimulated guanylyl cyclase activity plays a critical role in the induction of LTP of C-fiber-evoked field potentials in the spinal cord, whereas NO-related poly-ADPRT activity contributes to the maintenance of spinal LTP.     

1,25-二羟维生素D_3对脊柱结核患者外周血单个核细胞的NO及iNOS的影响研究

目的:研究1,25-二羟维生素D3(DHVD3)作用下脊柱结核患者外周血单个核细胞(PBMC)中一氧化氮(NO)及诱导型一氧化氮合酶(iNOS)含量变化,探讨其对脊柱结核患者的免疫调节作用。方法:患者PBMC分为试验组(加入DHVD3)和对照组(加入培养基),接种卡介苗后培养;采用硝酸还原酶法测定不同时间点(0、3、6、9、12d)试验组和对照组培养上清液中NO的相对吸光度值,分析其变化规律;于第6天收获2组培养细胞,提取细胞总RNA,逆转录后,定量聚合酶链反应(PCR)扩增,对目的基因iNOS及参照基因3-磷酸甘油醛脱氢酶的mRNA进行分析,用相对定量方法2-ΔΔCt比较其差异。结果:细胞培养第6天,试验组NO的相对吸光度值和iNOS的mRNA含量均高于对照组(P<0.05)。结论:DHVD3可使脊柱结核患者PBMC内iNOS的含量增加,进而促进NO的分泌,从而增强单个核细胞对结核杆菌的吞噬作用。