神经生长因子对小鼠突触体内Ca2+水平的调节作用

观察了多次海马内微注射NGF对小鼠突触体内游离钙水平的影响,并在离体情况下观察NGF对EGTA和CaCl₂分别造成突触体内低钙和高钙状态的调节作用。结果如下:(1)在体实验表明,一定剂量的NGF可显著降低老年小鼠海马突触体内游离钙水平(P<0.05);(2)离体实验表明,当突触体游离钙水平降低时,适当剂量的NGF具有升高游离钙水平的作用;而突触体内游离钙水平升高时,则NGF有降低游离钙水平的作用。提示NGF对游离钙水平的双向调节作用可能是NGF改善老年性记忆衰退的作用机制。     

知母总皂苷对老年大鼠学习记忆行为和海马突触相关蛋白表达的影响

目的探讨知母总皂苷(SAaB)对老年大鼠学习记忆能力及突触相关蛋白表达的影响。方法 ig给予18个月龄SD大鼠SAaB 100和200 mg.kg-1,每天1次,连续9周,第8周开始进行Morris水迷宫实验,记录逃避潜伏期及各象限游泳时间。免疫组织化学法观察海马突触素蛋白(SYP)分布。Western印迹法检测CA3区SYP、突触后致密蛋白95(PSD95)、磷酸化蛋白激酶B(p-Akt)和磷酸化雷帕霉素靶蛋白(p-mTOR)蛋白分布。结果与青年大鼠对照组比较,老年对照组大鼠逃避潜伏期显著增加,原平台象限游泳时间占总时间的百分比显著缩短(P<0.05),海马SYP,PSD95,p-Akt和p-mTOR表达显著降低(P<0.01)。与老年对照组相比,给予SAaB后,青年大鼠逃避潜伏期显著缩短,原平台象限游泳时间占总时间的百分比显著增加(P<0.05);海马SYP,PSD95,p-Akt和p-mTOR表达显著增加(P<0.01)。结论 SAaB能显著改善老年大鼠学习记忆能力,可能与上调SYP和PSD95表达及激活Akt/mTOR信号通路有关。     

阿托伐他汀对Aβ_(1-42)诱导的大鼠AD模型保护作用及其机制研究

目的观察阿托伐他汀(atorvastatin,Ato)对Aβ1-42诱导的AD大鼠学习记忆功能、炎症因子释放以及突触素(synaptophysin,SYP)和磷酸化JNK(p-JNK)蛋白表达的影响及机制。方法选用健康SD大鼠60只,随机分为4组:正常对照组、Aβ1-42组、Ato+Aβ1-42组、Ato组,每组15只,采用侧脑室注射给药。应用酶联免疫吸附(ELISA)法检测AD大鼠海马组织上清液内白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)、白细胞介素-4(IL-4)含量;Morris水迷宫实验观察AD大鼠的行为学变化;Western blot法检测AD大鼠海马突触素(synaptophysin,SYP)、pJNK蛋白表达水平。结果与正常对照组相比,脑室注射Aβ1-42后大鼠出现明显的学习记忆障碍,即逃避潜伏期明显延长,原平台象限游泳时间占总游泳时间百分比明显降低(P<0.01);海马组织上清液中IL-1β、IL-6、TNF-α的含量明显增加(P<0.01);SYP蛋白表达量明显减少(P<0.01);pJNK蛋白表达水平明显增加(P<0.01)。Ato给药后可明显对抗Aβ1-42引起的大鼠学习记忆障碍,抑制Aβ1-42引起的IL-1β、IL-6、TNF-α含量(P<0.05,P<0.01)、SYP蛋白表达增加(P<0.01)及p-JNK蛋白表达水平明显减少(P<0.05)。结论 Ato能够明显改善Aβ1-42引起的AD大鼠学习记忆障碍、炎症细胞因子释放增加及SYP蛋白表达降低,这种保护作用可能与Ato抑制JNK信号转导通路的激活有关。     

五味子醇甲对APP/PS1双转基因痴呆模型小鼠脑组织突触素、α-突触核蛋白表达的影响

目的观察五味子醇甲对APP/PS1双转基因痴呆模型小鼠脑组织的影响及机制。方法选用APP/PS1双转基因小鼠作为痴呆小鼠模型,五味子醇甲灌胃给药(10 mg·kg-1.d-1),4周后行为学测试,行为学测试后,断头处死,制作脑组织石蜡切片。HE、尼氏染色检测小鼠脑组织的病理形态改变;免疫组织化学方法检测小鼠脑组织突触素(synaptophysin,SYP)、突触核蛋白(α-synuclein,α-syn)的表达。结果五味子醇甲可改善APP/PS1双转基因痴呆模型小鼠脑组织的病理形态改变,提高SYP表达,降低α-syn表达。结论五味子醇甲可通过减轻脑组织神经元变性、脱失,改善突触功能等途径起到防治老年性痴呆(Alzheimer'sdisease,AD)的作用。     

知母皂苷元通过上调PI3K/Akt信号通路减轻淀粉样β蛋白诱导的乳大鼠海马神经元突触损伤

目的 探讨知母皂苷元(Sar)减轻淀粉样β蛋白(Aβ)诱导的海马神经元突触损伤的信号转导机制。方法 取出生0~24 h SD乳大鼠海马神经元,体外培养7 d。海马神经元分别加入磷脂酰肌醇-3-激酶(PI3K)特异性阻断剂LY294002 30 μmol·L^-1或蛋白激酶B(Akt)特异性阻断剂曲西立滨1 μmol·L^-1 1 h后,加Sar 30和100 μmol·L^-1作用1 h,再加Aβ_1-42 50 nmol·L^-1作用24 h。应用突触囊泡蛋白(SYP)免疫荧光染色观察突触的改变。Western蛋白质印迹法检测海马神经元SYP、磷酸化Akt(p-Akt)和磷酸化糖原合成酶3β(p-GSK3β)表达水平的改变。结果 与正常对照组相比,Aβ_1-42组培养的海马神经元SYP, p-Akt和p-GSK3β表达水平明显减低(P<0.01)。与Aβ_1-42组相比,Aβ_1-42+Sar 30和100 μmol·L^-1组海马神经元SYP, p-Akt和p-GSK3β表达水平明显增加(P<0.01)。给予LY294002作用后,SYP和p-Akt表达水平明显降低(P<0.05)。给予曲西立滨作用后,SYP和p-GSK3β表达水平明显降低(P<0.05)。单独给予LY294002,海马神经元SYP表达无变化,p-Akt表达水平明显降低(P<0.01)。单独给予曲西立滨,海马神经元SYP和p-GSK3β蛋白表达水平明显降低(P<0.01)。结论 Sar通过上调PI3K/Akt/GSK3β信号通路对抗Aβ_1-42诱导的海马神经元突触损伤。     

G蛋白介导的信号传递在阿尔采末病中的功能变化

阿尔采末病 (AD)是一种神经退行性疾病 ,病理特点主要有 β 淀粉样蛋白的沉积和神经纤维缠结的形成。一直以为AD脑中神经元功能受损与突触后受体变化无关 ,但近来越来越多的证据表明中枢神经递质受体 /G蛋白介导的腺苷酸环化酶和磷酯酰肌醇水解信号转导途径在AD病程中均受到不同程度的损害 ,这亦解释了神经递质替代疗法在治疗AD中疗效有限的原因 ,同时为进一步研究和开发防治AD新药提供新思路     

神经生长因子治疗阿尔采末病的胆碱能神经机制

神经生长因子 (nervegrowthfactor,NGF)是中枢胆碱能神经元存活和功能维持最重要的神经营养因子之一 ,对阿尔采末病 (Alzheimersdisease,AD)的治疗潜力已引起人们极大兴趣。投射于大脑皮质和海马的基底前脑胆碱能神经元退变是AD早期病变 ,也是导致患者认知功能降低的主要原因。NGF可通过兴奋残存神经元上高亲和性TrkA受体 ,促进中枢胆碱能神经元的存活和正常功能的发挥 ,同时神经元激活也使其自身免受AD的有害作用 ,即所谓“useitorloseit”现象。然而 ,NGF不能透过血脑屏障 ,如何使外源性NGF到达脑内靶区是亟待解决的难题 ,一旦获得理论和技术上的突破 ,NGF防治AD的临床应用才更具价值     

外周组织损伤对脊髓AMPA受体突触表达的影响及其机制

目的研究外周组织损伤对脊髓背角AMPA受体突触表达的影响及其分子调节机制。方法小鼠足底皮下注射完全弗氏佐剂(CFA),建立炎性疼痛模型;24 h后分离L4～L5脊髓背角,提取"富含突触后致密质(PSD)"的亚细胞结构,免疫印迹法检测AMPA受体GluR2亚基突触表达的变化,并观察cAMP依赖性蛋白激酶(PKA)在调节GluR2突触含量中的作用。结果 CFA在引发痛觉超敏的同时,脊髓背角GluR2的突触含量明显升高。虽然PKA抑制剂H-89并不影响正常小鼠的痛阈及GluR2的突触含量,但H-89却能有效缓解炎性痛觉超敏,同时完全翻转CFA诱发的GluR2亚基在突触中的过量表达。结论外周组织损伤通过激活脊髓PKA,明显提高AMPA受体GluR2亚基在脊髓突触中的含量,可能是慢性炎性疼痛形成的重要机制。     

神经生长因子改善衰老性记忆障碍及突触机制的探讨

目的　探讨神经生长因子(NGF)改善衰老性记忆障碍的机制。方法　采用开场行为和一次性被动回避反应模型,观察海马内微量注射NGF对衰老小鼠自发活动和记忆巩固过程的影响, 同时用Ca²⁺荧光探针Fura-2/AM和AR-CM-MIC阳离子测定系统测定海马突触体游离钙水平,以³H-Leu为标记物测定海马突触体总蛋白的合成量。结果　NGF使衰老小鼠在新异环境中的自发活动和探究行为明显增多,并显著延长电击后24 h的步入潜伏期(STL); NGF显著降低衰老小鼠海马突触体内的高钙水平,并使海马突触体蛋白质的³H-Leu参入量显著增加。结论　NGF改善衰老性记忆障碍与其降低海马突触体内高钙水平,并由此促进海马突触体蛋白质的合成有关。     

脊髓背角PKC在慢性炎性疼痛中的作用及其机制

目的探讨蛋白激酶C(protein kinase C,PKC)的抑制剂和激动剂对痛觉超敏的影响及其分子机制。方法小鼠后趾皮下注射完全弗氏佐剂(complete Freund's adjuvant,CFA)建立炎性疼痛模型;鞘内给予PKC抑制剂白屈菜赤碱(chelerythrine,CHE)或激动剂Phorbol 12-myristate 13-acetate(PMA)前后,测定小鼠缩足阈值;随后立即分离脊髓背角,免疫印迹法检测NMDA(N-methyl-D-aspartate)型谷氨酸受体的突触表达。结果 PKC抑制剂CHE在缓解炎性痛觉超敏的同时,明显翻转脊髓NMDA受体NR2B亚基的突触表达亢进;而正常小鼠鞘内给予PKC激动剂PMA,可模拟CFA的效应,即:诱发痛觉超敏,并特异性增加NR2B亚基的突触含量。结论 PKC通过调节脊髓NMDA受体NR2B亚基的突触表达,参与炎性疼痛的形成。     

Aurora激酶及其抑制剂研究状态综述

Aurora激酶家族是苏氨酸/丝氨酸激酶,在有丝分裂的染色体排列,分离和胞质分裂中起重要作用。最近的研究发现,Aurora激酶在大量人类实体瘤和血液恶性肿瘤中过表达,表明其是开发抗肿瘤药物的重要靶点。本文就近几年国内外对Aurora激酶的研究,对Aurora激酶的生物学功能、与肿瘤的关系及其抑制剂的研究进展进行综述。     

Cocaine treatment- and withdrawal-induced alterations in the expression and serine phosphorylation of the NR1 NMDA receptor subunit

Abstract Rationale. Repeated administration of cocaine alters the expression of the NMDA receptor subunits, NR1 and NR2B in a region- and withdrawal time-dependent manner. Objective. The present experiments extend these findings by characterizing the effects of cocaine withdrawal on specific NR1 splice variant expression. In addition, changes in the serine phosphorylation of NR1 and in the expression of postsynaptic density protein, PSD-95, were measured as potential molecular mechanisms for the cocaine-induced alterations in receptor subunit expression. Methods. Rats were injected with either saline or cocaine for 7 consecutive days and were sacrificed 24 h or 14 days following the last injection. Brain regions putatively identified in mediating the behavioral and neurochemical effects of cocaine, such as the frontal cortex, neostriatum, and hippocampus, were microdissected and used for immunoblotting experiments. In addition, drug-induced changes in NR1 phosphorylation in frontal cortex were investigated using immunohistochemistry. Results. After 2 weeks of withdrawal from cocaine, NR1 subunit expression in the neostriatum was down-regulated ~27%, as compared to saline-treated control rats. Further, at 24 h but not 14 days of withdrawal, phosphorylation of serine residues 896 and 897 was reduced ~34% in the frontal cortex of rats treated with cocaine, as compared to controls. Conclusions. Results suggest that early changes in kinase or phosphatase activity may contribute to prolonged cocaine-induced alterations in NR1 expression. Thus, NR1 phosphorylation could be important for the activation of pathways that are substrates for the effects of cocaine exposure and withdrawal. Electronic Publication     

Effect of barbiturates on polyphosphoinositide biosynthesis and protein kinase C activity in synaptosomes

Previously, it has been found that phenobarbital inhibited protein kinase C (PKC) and the enzymes of the metabolism of polyphosphoinositide, especially phosphatidylinositol 4-phosphate (PIP) kinase (PIP-kinase). As a continuation of these studies, a number of barbiturates (barbituric acid, barbital, butabarbital, pentobarbital, amobarbital, phenobarbital, secobarbital and hexobarbital) were tested for inhibition of these enzymes and also of phosphatidylinositol (PI) kinase (PI-kinase), in a synaptosomal preparation at pH 7.8 from the brain of rat. All compounds, except barbituric acid (and Na-barbital for PI-kinase) inhibited the three kinases. However, PKC was approximately 3–5 fold more sensitive to inhibition by the drugs (measured by Ki values) than PIP-kinase, which was 2- to 4-fold more sensitive than PI-kinase. The inhibitory potency of the drugs increased with their lipophilicity, although to a lesser degree than expected from the differences in partition coefficients; the largest deviation from a positive correlation (i.e. hexobarbital) may be the result of the blockade of an imide (-NH) group at one position of the barbituric ring. Concentrations of drugs (after correction for the greater than normal ionization (pH 7.8) of the drugs in the assays) necessary for half-maximal inhibition were well within, or smaller than, those reported necessary for in vitro blocking of nerves. The possibility, therefore, exists that the physiological effects of the barbiturates are, in part, the result of an inhibition of protein kinase C and PIP-kinase.     

Protein kinase inhibitors: breakthrough medicines and the next generation

In this issue of Expert Opinion on Investigational Drugs, several protein kinases families and pathways underlying cancer and other diseases are reviewed and several small molecule inhibitors that are in clinical trials are further described. Highlights of these reviews and drug evaluations are summarized in this editorial.     

CK—MB与CK比率界值在鉴别心肌梗死与骨骼肌损伤中的应用

目的探讨CK-MB/CK比值鉴别诊断急性心肌梗死(简称心梗)和肌损伤的可行性.方法采集心梗患者和肌损伤患者的肌酸激酶(CK)、肌酸激酶MB同工酶(CK-MB)资料,进行显著性分析,确定不同诊断界值后分别计算敏感性、特异性和诊断指数.在分析比较的基础上,最后确定鉴别诊断的比率界值.结果心梗患者CK对数均值为617(162～3495)u/L,肌损伤组为589(165～5452)u/L,两组比较无显著性差异(t=1.74,P＞0.05).CK-MB心梗组对数均值高于肌损组,分别为68(9～530)u/L和24(8～183)u/L,t=5.83,P＜0.01,但总体诊断指数小于150%.CK-MB/CK比值,心梗组均值亦高于肌损组,分别为(11.4±4.08)%和(4.47±2.07)%,t=11.17,P＜0.01.将比率界值定为6%,其诊断指数可达176%,优于CK-MB峰值的诊断效率.结论以CK-MB/CK比率界值作为鉴别诊断心梗和肌损伤的指标是可行的,同时提出了用CK、CK-MB诊断心梗的4条标准.     

Targeting cell cycle kinases and kinesins in anticancer drug development

The cell cycle is regulated by kinases such as the cyclin-dependent kinases (CDKs) and non-CDKs, which include Aurora and polo-like kinases, as well as checkpoint proteins. Mitotic kinesins are involved in the establishment of the mitotic spindle formation and function, and also play a role in cell cycle control. The disruption of the cell cycle is a hallmark of malignancy. Genetic or epigenetic events result in the upregulation of these kinases and mitotic kinesins in a myriad of tumour types, suggesting that their inhibition could result in preferential targeting of malignant cells. Such findings make the development of these inhibitors a rational and attractive new area for cancer therapeutics. Although challenges of potency and non-specificity have hampered their progress through the clinic, several novel compounds are presently in various phases of clinical trial evaluation.     

血清CK-MM亚带MM_3/MM_1比值与CK-MB和Mb测定早期诊断急性心肌梗塞的比较

本文采用琼脂凝胶电泳法测定62例急性心肌梗塞(AMI)和19例心绞痛(AP)病人血清肌酸激酶MM同功酶(CK-MM)亚带MM_3/MM_1比值及肌酸激酶同功酶(CK-MB)和肌红蛋白(Mb)的改变,并比较它们在AMI中的诊断价值。结果表明:AMI组首次血清的MM_3/MM_1比值为1.85±2.01(x±s),AP组为0.24±0.14,二者比较差异非常显著(P<0.01)。首次血清和系列测定对AMI的早期诊断价值高于CK-MB和Mb。本组结果亦表明MM_3/MM_1比值的累积阳性率于梗塞发生后6小时达100％。提示血清CK-MM亚带MM_3/MM_1比值异常是AMI早期诊断中敏感而特异的酶学诊断指示。     

Identification of a Novel and Selective Series of Itk Inhibitors via a Template-Hopping Strategy

相似文献