依托咪酯对神经元缺氧损伤的保护及其作用机制

目的观察依托咪酯对大鼠海马神经元缺氧损伤的保护作用及其机制。方法用原代培养的新生大鼠海马神经细胞建立缺氧模型,用MTT法测定神经元存活率。采用激光扫描共聚焦显微镜动态监测单个海马神经元[Ca2+]i随缺氧或加入谷氨酸、KC l前后的实时变化。结果依托咪酯在1.2~4.8 mg.L-1范围内,可剂量依赖性地降低神经元缺氧损伤时的细胞死亡率(P<0.05)。0.3~4.8 mg.L-1依托咪酯能抑制缺氧及50 mmol.L-1KC l引起的[Ca2+]i升高(P<0.05),仅在4.8 mg.L-1时才抑制1 mmo.lL-1谷氨酸所致的[Ca2+]i升高(P<0.01)。结论依托咪酯对离体大鼠海马神经元缺氧性损伤具有保护作用,其机制可能与依托咪酯抑制缺氧引起[Ca2+]i异常升高有关。     

超低分子肝素对原代培养大鼠大脑皮质神经元化学诱导损伤的保护作用

目的探讨超低分子肝素(ULMWH)对不同化学诱导损伤大脑皮质神经元的保护作用。方法谷氨酸、叠氮钠、KCl和咖啡因诱导损伤原代培养的大鼠大脑皮质神经元,观察神经元存活率、培养液中乳酸脱氢酶(LDH)漏出量及细胞内游离钙离子浓度([Ca2+]i)。结果ULMWH(0.01～1.0mg.L-1)预处理24h可显著提高谷氨酸损伤神经元的存活率,降低细胞LDH的漏出量和[Ca2+]i,高浓度(1.0mg.L-1)时对叠氮钠引起的神经元损伤也有一定的保护作用,但对咖啡因和KCl所致的神经元损伤无影响。结论ULMWH对谷氨酸和叠氮钠所致大鼠大脑皮质神经元损伤有一定的保护作用,可能与其抑制[Ca2+]i升高有关;但不能对抗KCl和咖啡因所致的皮质神经元损伤。     

丹参注射液抗乳酸神经毒性作用及其机制研究

目的　研究丹参注射液抗乳酸神经毒性作用及其机制。方法　利用SD大鼠大脑皮质培养神经元 ,通过MTT法或台盼蓝法测定细胞活力 ;以Fura 2 /Am为荧光指示剂 ,测定细胞内游离钙离子浓度 ( [Ca2 +]i)。结果　乳酸对神经元具有毒性作用 ,pH下调到相应水平对神经元无影响 ,终浓度为 2 0、2 0 0g·L-1的丹参注射液可以减轻乳酸引起的神经元损伤 ,具细胞保护作用 ;与对照组、pH下调组比较 ,乳酸可以增加神经细胞的静息 [Ca2 +]i水平 ;2 0、2 0 0 g·L-1浓度的丹参注射液可以抑制乳酸引起的静息 [Ca2 +]i升高 ,在高浓度的条件下 ( 2 0 0 g·L-1) ,对氯化钾、谷氨酸刺激诱发的[Ca2 +]i升高有抑制作用。结论　乳酸的神经毒性作用与pH下调无关 ,乳酸作为一种有机酸 ,可以直接促进 [Ca2 +]i升高 ;丹参对乳酸引起的损伤具有保护作用 ,其机制与其抑制钙超载有关     

ATP对大鼠三叉神经节小直径神经元胞内钙浓度的调制作用及其机制

目的探讨神经递质ATP通过何种途径引起大鼠三叉神经节(trigeminal ganglion,TG)小直径神经元胞内钙离子浓度升高。方法在急性分离的TG神经元上,应用钙离子成像技术检测胞内游离Ca2+浓度([Ca2+]i)的变化。结果在大鼠TG小直径神经元中,ATP(100μmol·L-1),thap-sigargin(1μmol·L-1,内质网钙泵抑制剂)和咖啡因(20mmol·L-1,内质网钙离子通道开放剂)在正常细胞外液和去除细胞外Ca2+的情况下,均能够引起细胞[Ca2+]i升高。在细胞外无Ca2+条件下,thapsigargin能够可逆地抑制ATP引起细胞内[Ca2+]i升高(n=8,P<0.01),而咖啡因对ATP引起的细胞内[Ca2+]i升高无影响(n=6,P>0.05)。然而在正常外液中,thapsigargin不能完全抑制ATP引起的细胞内[Ca2+]i升高,不过ATP引起的细胞内[Ca2+]i升高的幅度明显地低于thapsigargin处理前(n=7,P<0.05)。结论在大鼠TG小直径神经元中,存在有IP3敏感钙库和Ryanod-ine敏感钙库。ATP可通过激动P2Y受体引起IP3敏感钙库的Ca2+释放,也可通过激动P2X受体引起细胞外钙内流。     

七氟醚对神经元缺氧损伤的保护及其作用机制

目的 观察七氟醚对大鼠海马神经元缺氧损伤的保护作用及其机制.方法 用原代培养的新生大鼠海马神经细胞建立缺氧模型,用MTT法测定神经元存活率.采用激光扫描共聚焦显微镜动态监测单个海马神经元[Ca2 ]i随缺氧或加入KCl前后的实时变化.结果 七氟醚在2MAC(肺泡气最小有效浓度),可降低神经元缺氧损伤时的细胞死亡率(P＜0.05).0.5～2MAC七氟醚能抑制缺氧及50 mmol/L KCl引起的[Ca2 ]i升高(P＜0.05).结论 七氟醚对离体大鼠海马神经元缺氧性损伤具有保护作用,其机制可能与七氟醚抑制缺氧引起[Ca2 ]i异常升高有关.     

八肽胆囊收缩素及其受体拮抗剂对吗啡戒断大鼠脑内[Ca~(2+)]_i和CaM活性的影响

目的观察八肽胆囊收缩素(CCK-8)及其受体拮抗剂对吗啡戒断大鼠皮质、海马、纹状体神经细胞内[Ca2+]i和CaM活性的影响。方法剂量递增法(10⁵0 mg·kg-1)连续5 d皮下注射吗啡建立吗啡依赖模型,并给予腹腔注射纳洛酮(5 mg·kg-1)催促戒断,采用流式细胞术检测大鼠皮质、海马、纹状体[Ca2+]i和CaM活性的变化。结果 (1)与盐水对照组相比,吗啡依赖组大鼠皮质、海马、纹状体内[Ca2+]i和CaM活性均明显升高;纳洛酮催促戒断后[Ca2+]i和CaM活性较吗啡依赖组均明显降低;(2)CCK-8及CCK-1受体拮抗剂L-364,718、CCK-2受体拮抗剂LY-288,513均使吗啡戒断大鼠海马和纹状体内[Ca2+]i和CaM活性明显升高,但皮质内[Ca2+]i和CaM活性无明显变化。结论 CCK-8及其受体拮抗剂对吗啡依赖大鼠戒断反应的作用可能与其对相关脑区神经细胞内[Ca2+]i和CaM活性的调节有关。     

舒郁胶囊对大鼠海马原代培养神经元Ca~(2+)-CaM通路的作用

目的观察海马神经元内Ca2+浓度和CaM蛋白水平表达变化,探索复方舒郁胶囊治疗抑郁情绪的微观作用机制。方法采用孤养结合慢性温和刺激复制抑郁情绪大鼠模型,以调肝方药舒郁胶囊及其君药柴胡提取物进行干预,氟西汀作为阳性对照药,制备各组大鼠血清;运用原代无血清培养技术培养大鼠海马神经元,以制备的各组大鼠含药血清孵育神经元;采用荧光探针Fluo-3/AM染色和细胞免疫荧光技术,分别测定海马神经元胞内[Ca2+]i和CaM蛋白表达水平。结果与正常组相比,模型血清组细胞内[Ca2+]i和CaM蛋白表达水平明显降低(P<0.05);各含药血清组神经元胞内[Ca2+]i和CaM蛋白水平较模型血清组明显升高(P<0.05),与正常血清组差异无显著性。结论舒郁胶囊调控海马神经元胞内Ca2+-CaM体系的变化可能是其治疗抑郁情绪的作用机制之一。     

异丙酚对神经元缺氧损伤的保护及其作用机制

目的　研究异丙酚对离体大鼠海马神经元缺氧损伤的保护作用及其机制。方法　以原代培养的大鼠海马神经元作为研究对象 ,建立缺氧、H2 O2 和谷氨酸损伤模型 ,用MTT法测定神经元存活率。采用激光扫描共聚焦显微镜动态监测缺氧前后 ,单个海马神经元内Ca2 + 浓度和线粒体膜电位 (△Ψm)的变化。用电子自旋共振技术测定异丙酚对羟基自由基和超氧阴离子自由基的清除作用。结果　 6～ 4 8mg·L-1浓度的异丙酚可明显降低神经元缺氧损伤时的细胞死亡率 (P <0 0 1) ,作用程度均呈剂量相关 (r =0 89,P <0 0 5 ) ;2 4～ 4 8mg·L-1浓度的异丙酚可明显降低H2 O2 损伤时的细胞死亡率 (P <0 0 1) ;12～ 4 8mg·L-1浓度的异丙酚可明显降低谷氨酸损伤时的细胞死亡率 (P <0 0 1)。 3～ 4 8mg·L-1异丙酚对缺氧诱发的细胞内钙离子超载有抑制作用(P <0 0 5 ) ;12、4 8mg·L-1异丙酚能减缓缺氧引起的△Ψm降低 (P <0 0 1)。 12、4 8mg·L-1异丙酚对羟基自由基的清除率分别为 17 1%和 2 1 1% ,但对超氧阴离子自由基无清除作用。结论　异丙酚对离体培养的大鼠海马神经元缺氧性损伤具有保护作用 ,其作用机制部分与异丙酚抑制缺氧引起的 [Ca2 + ]i 异常升高、抑制线粒体膜电位的下降和清除羟基自由基有关     

灯盏花素对人脐静脉内皮细胞胞内Ca~(2+)水平的调控作用

目的探讨灯盏花素对培养的人脐静脉内皮细胞(HUVECs)胞内Ca2+水平([Ca2+]i)的调控作用。方法采用新一代Ca2+荧光探针Fluo-3/AM标记培养的HUVECs,激光共聚焦显微镜检测细胞胞内钙荧光信号,观察灯盏花素对培养的HUVECs胞内Ca2+水平的调控作用。结果在胞外有Ca2+或无Ca2+的情况下,灯盏花素均可引起[Ca2+]i的短暂性升高;灯盏花素的Ca2+释放作用与钙泵抑制剂CPA存在着交迭;灯盏花素能够抑制由KCl所引起的[Ca2+]i的升高;灯盏花素对胞内Ca2+池耗竭后胞外复Ca2+所引起的钙内流无明显阻断作用。结论灯盏花素可引起胞内Ca2+池的Ca2+释放,其释放的Ca2+来自CPA敏感的Ca2+池。灯盏花素也可抑制经电压依赖性Ca2+通道的Ca2+内流,对Ca2+池耗竭后引起的Ca2+内流通道无明显阻断作用。     

地佐环平对缺血突触体氨基酸释放和游离钙的影响(英文)

目的　初步探讨地佐环平 (MK 80 1)对脑缺血的保护作用与兴奋性氨基酸 (EAA)和抑制性氨基酸(IAA)释放的关系。方法　营养液中去除糖和氧 ,建立大鼠脑突触体缺血模型 ,检测静息及高钾去极化状态下 ,缺血突触体EAA和IAA释放量及游离钙浓度。结果　大鼠突触体缺血状态致天冬氨酸和甘氨酸、牛磺酸、γ 氨基丁酸释放量明显增加 ,而谷氨酸亦有增加趋势。缺血 + 5 0mmol·L- 1K+刺激后 ,上述EAA及IAA释放量均进一步增加。静息及去极化状态下的缺血突触体游离钙浓度显著增加。MK 80 10 .1mmol·L- 1可显著阻遏静息及去极化状态缺血突触体释放EAA及IAA ,但对EAA的抑制作用更明显 ;同时亦明显降低两种状态下缺血突触体内游离钙浓度。结论　MK 80 1的抗脑缺血致脑损伤作用 ,至少部分与其对抗缺血引起的突触体内游离钙浓度升高和EAA释放量增加的作用有关。     

β-内啡肽对谷氨酸神经毒性作用的影响

采用形态学观察、β-内啡肽(β-End)放射免疫测定及单细胞内游离钙浓度——[Ca²⁺]i检测等方法,观察了β-End对谷氨酸单钠(MSG)诱发神经元损伤的影响,分析了可能的作用机制。结果表明,β-End可以明显加重MSG诱发的下丘脑弓状核神经元的损伤;β-End和MSG诱发的[Ca²⁺]i增高可被维拉帕米部分逆转。另外,吗啡可以进一步加剧MSG诱导的各脑区β-End含量的变化。提示β-End可以明显地加剧MSG的神经毒性作用,其机制与MSG能诱发脑内β-End的含量的增多及β-End可进一步破坏MSG引起的胞内钙稳态失衡有关。     

8-(N,N-二乙铵)-n-辛基-3,4,5-三甲氧基苯甲酸酯对谷氨酸诱导神经细胞DNA损伤的影响

目的研究 8 (N ,N 二乙铵 ) n 辛基 3,4 ,5 三甲氧基苯甲酸酯 (TMB 8)对谷氨酸诱导神经细胞DNA损伤的影响。方法用谷氨酸诱导培养的大鼠皮层神经细胞DNA断裂 ,观察TMB 8对神经细胞DNA断裂和线粒体功能的影响。结果TMB 8能明显减轻谷氨酸诱导的大鼠皮层神经细胞DNA断裂并能改善线粒体功能。结论TMB 8具有抑制神经细胞DNA损伤的作用 ,其机制可能与其降低细胞内游离钙、改善线粒体功能和减轻谷氨酸的氧化毒性有关     

β—内啡肽增强谷氨酸神经毒性

探讨β－内啡肽对谷氨酸单钠诱导的神经毒性的影响。方法：形态学观察、神经元面积图象分析、线粒体膜蛋白结合钙和单细胞内游离钙浓度测定。结果：β－内啡肽在０．５－５．０ｍｇ·ｋｇ＾－１范围内以剂量依赖方式加剧谷氨酸单钠诱导的下丘脑弓状核神经元损伤，谷氨酸单钠诱导的线粒体膜蛋白结合钙增多可以被β－内啡肽２ｇ·Ｌ＾－１加强，谷氨到单钠诱导的单细胞内钙浓度升高也被β－内啡肽２ｇ·Ｌ＾－１从３２０±８４提高至５     

Opposing effects of cyclooxygenase-2 selective inhibitors on oxygen-glucose deprivation-induced neurotoxicity

Cyclooxygenase-2 inhibitors protect against excitotoxicity in vitro yet provide conflicting results in in vivo models of ischemia. To bridge the gap in understanding the discrepancies among these studies, the effects of different cyclooxygenase-2 inhibitors were studied in an in vitro model of ischemia. Oxygen-glucose deprivation (OGD) induced cyclooxygenase-2 protein expression in neuronal cortical cultures. Cyclooxygenase-2 inhibitors exhibited opposing effects on neuronal death induced by OGD. The acidic sulfonamides, N-(2-cyclohexyloxy-4-nitrophenyl) methanesulfonamide (NS-398) and N-(4-nitro-2-phenoxyphenyl)-methanesulfonamide (nimesulide), aggravated neuronal death by enhancing OGD-induced increases in extracellular glutamate and intracellular Ca2+ levels. In contrast, 1-[(4-methylsulfonyl)phenyl]-3-tri-fluoromethyl-5-(4-fluorophenyl)pyrazole (SC-58125) dose-dependently protected cultures against OGD by suppressing increases in extracellular glutamate and intracellular Ca2+ levels. The NS-398-induced aggravation of neuronal death was lost if the inhibitor was added only following the OGD. The timing of inhibitor application also determined its effects on N-methyl-D-aspartate (NMDA)-induced excitoxicity. NS-398 was protective when added both during and post-NMDA exposure, but not if NS-398 was also applied for 60 min prior to the insult. In contrast, SC-58125 afforded protection against NMDA in the presence or absence of a pre-incubation period. This study demonstrates that certain cyclooxygenase-2 inhibitors have opposing effects on neuronal survival depending on the timing of application and the nature of the insult. These results may account for the discrepancies among previous studies which used different inhibitors and different models of neurotoxicity.     

Antagonistic effects of extract from leaves of ginkgo biloba on glutamate neurotoxicity.

AIM: To determine whether the extract of leaves of Ginkgo biloba L (EGb) and several active constituents of EGb have protective effects against glutamate (Glu)-induced neuronal damage. METHODS: Microscopy and image analysis of nucleus areas in the arcuate nuclei (AN) of mice were made. The neuronal viability in primary cultures from mouse cerebral cortex was assessed using MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide] staining and the intracellular free calcium concentration ([Ca2+]i) of single neuron was measured using Fura-2. RESULTS: EGb (2.5 mg.L-1) and its constituent ginkgolide B (Gin B, 2 mg.L-1) protected the neuronal viability against Glu-induced injury, and prevented the Glu-induced elevation in [Ca2+]i. EGb (3-10 mg.kg-1) attenuated the decrease of nucleus areas in arcuate nuclei induced by Glu (1 g.kg-1, s.c.). CONCLUSION: EGb and Gin B prevent neurons from Glu neurotoxicity through reduction of the rise in [Ca2+]i.     

Glutamate preconditioning prevents neuronal death induced by combined oxygen-glucose deprivation in cultured cortical neurons

The study of ischemic tolerance is critical in the development of strategies for the treatment of ischemic stroke. We used the oxygen and glucose deprivation (OGD) paradigm in cultured cortical neurons as an in vitro approach to elucidate the mechanism of protection conferred by glutamate preconditioning. Pretreatment of neurons with N-methyl-d-aspartate (NMDA) receptor antagonists prevented OGD-induced cell death whereas alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptor and voltage-dependent Ca(++) channel (VDCC) blockers were without effect. Neurons preconditioned with glutamate exhibited resistant to damage induced by OGD. The ischemic tolerance depended on the duration of preconditioning exposure and the interval between preconditioning exposure and test challenge. Protective efficacy was blocked by the NMDA or AMPA receptor antagonists but not by the VDCC blocker. Furthermore, neuroprotective effect was not seen if extracellular Ca(++) was omitted or removed with EGTA. Pretreatment with staurosporin and 2-[N-(2-hydroxyethyl)]-N-(4-methoxybenzenesulfonyl)] amino-N-(4-chlorocinnamyl)-N-methylbenzylamine (KN93) but not 2-(4-Morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one (LY294002) or 1,4-diamino-2,3-dicyano-1, 4-bis[2-aminophenylthio] butadiene (U0126) significantly reduced ischemic tolerance. Preconditioning increased phosphorylated levels of cAMP responsive element binding protein (CREB) and pretreatment with CRE-decoy oligonucleotide completely blocked preconditioning-induced increase in cell viability. Importantly, glutamate preconditioning increased Bcl-2 expression that was blocked by KN93, staurosporin and CRE-decoy oligonucleotide. These results suggest that preconditioning with glutamate conferred neuroprotection against subsequent OGD by inducing p-CREB-mediated Bcl-2 expression.     

Neuroprotective effect of Sanguisorbae radix against oxidative stress-induced brain damage: in vitro and in vivo

Sanguisorbae radix (SR), the root of Sanguisorba officinalis L. (Rosaceae), has been traditionally used for its anti-inflammatory, anti-infectious and analgesic activities in Korea. Previous work has shown that SR prevents neuronal cell damage induced by Abeta (25--35) in cultured rat cortical neurons. The present study was carried out to further investigate the neuroprotective effect of SR on oxidative stress-induced toxicity in primary culture of rat cortical neurons, and on ischemia-induced brain damage in rats. SR, over a concentration range of 10--50 microg/ml, inhibited H2O2 (100 microM)-induced neuronal death, which was significantly inhibited by MK-801 (5 microM), an N-methyl-D-aspartate (NMDA) receptor antagonist, and verapamil (20 microM), an L-type Ca2+ channel blocker. Pretreatment of SR (10-50 microg/ml), MK-801 (5 microM), and verapamil (20 microM) inhibited H2O2-induced elevation of intracellular Ca2+ concentration ([Ca2+]i) measured by a fluorescent dye, Fluo-4 AM. SR (10-50 microg/ml) inhibited H2O2-induced glutamate release into medium measured by HPLC, and generation of reactive oxygen species (ROS) measured by 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA). In vivo, SR prevented cerebral ischemic injury induced by 2-h middle cerebral artery occlusion (MCAO) and 24-h reperfusion. The ischemic infarct and edema were significantly reduced in rats that received SR (10, 30 mg/kg, orally), with a corresponding improvement in neurological function. Catechin isolated from SR inhibited H2O2-induced neuronal death in cultures. Taken together, these results suggest that SR inhibits H2O2-induced neuronal death by interfering with the increase of [Ca2+]i, and inhibiting glutamate release and generation of ROS, and that the neuroprotective effect of SR against focal cerebral ischemic injury is due to its anti-oxidative effects. Thus SR might have therapeutic roles in neurodegenerative diseases such as stroke.