突触后密度蛋白93基因敲除抑制血小板活化因子性神经元损害

目的　探讨血小板活化因子 (PAF)所致的神经元毒性损伤是否受突触后密度蛋白 93(PSD93 )基因调控。方法　用PAF处理培养的野生型和PSD93 基因敲除型的小鼠皮质神经元 ;经碘化物 (PI) /钙黄绿素(Calcein)染色 ,荧光显微镜观察并计算细胞死亡率 (% ) ;细胞生存能力检测 (MTT)神经元生存能力 ;免疫印迹法测定PSD93 和PSD95蛋白的表达。结果　野生型神经元表达PSD93 和PSD95蛋白 ,PSD93 基因敲除型只表达PSD95,不表达PSD93 ;基因敲除型的小鼠皮质神经元凋亡明显低于野生型 (P <0 0 5 ) ,生存能力高于野生型(P <0 0 1)。结论　PSD93 基因敲除抑制PAF所致的神经元损害     

血小板活化因子介导神经元损伤与天门冬氨酸信号通路的研究

目的　探讨血小板活化因子 (PAF)诱导的神经元凋亡是否涉及N 甲基 D 天门冬氨酸 (NMDA)信号传导通路。方法　用原代小鼠大脑皮质神经元培养系统 ,不同剂量PAF处理神经元 2 4h或PAF受体拮抗剂 (BN 5 2 0 2 1)、NMDA受体拮抗剂 (MK 80 1)和一氧化氮合酶抑制剂 (L NAME)预处理 30min ;碘化物 (PI ) /calcein(钙黄绿素 )染色 ,荧光显微镜摄像 ,计算细胞死亡率。同时免疫印迹蛋白测定神经型一氧化氮合成酶(nNOS)表达水平及用3 H标记放免法检测nNOS的活性。结果　 (1)不同剂量 (0 0 1、0 1、0 3、0 6 μmol/L)的PAF处理神经元 2 4h ,均可致神经元死亡 ,0 3和 0 6 μmol/L组与对照组相比 ,差异均有显著性 (均 P <0 0 1)。(2 )PAF神经毒性作用不仅被BN 5 2 0 2 1所拮抗 ,MK 80 1、L NAME也可减轻其作用。 (3)PAF增加神经元的nNOS蛋白的表达 ,同时也增加其活性。结论　PAF对神经元的损伤作用与NMDA信号通路激活有关。     

神经干细胞分化的神经元离子型谷氨酸受体NMDA亚单位的mRNA和蛋白表达

目的在体外研究由大鼠神经干细胞(NSCs)分化而来神经元细胞中离子型谷氨酸NMDA受体表达。方法分离培养孕14～16d胎鼠皮质和海马神经干细胞，对NSCs进行nestin和分化鉴定。通过RT—PCR、Western blot免疫印迹和免疫组化检测NSCs分化的神经元细胞中离子型谷氨酸NMDA受体亚单位NR1、NR2A和NR2B的mRNA和蛋白表达。结果从孕14～16d胎鼠大脑中分离培养出NSCs，NSCs分化后的神经元可以表达离子型谷氨酸NMDA受体亚单位NR1、NR2A和NR2B。结论由NSCs分化而来的神经元能表达离子型谷氨酸NMDA受体。     

p150glued缺失小鼠的脊髓运动神经元中NMDA受体增多

目的 探讨运动神经元病致病基因Dctn1编码蛋白p150glued对小鼠脊髓运动神经元中N-甲基-D-天冬氨酸(NMDA)受体的影响。方法 利用蛋白印迹法检测p150glued缺失(cKO)小鼠及对照(Ctrl)小鼠脊髓中NMDA受体亚基NR1和NR2B的含量。利用免疫荧光染色法观察Ctrl和cKO小鼠脊髓运动神经元中NRI分布的变化。结果 与Ctrl小鼠相比,6月龄cKO小鼠脊髓组织中NR1和NR2B的蛋白水平明显增加,cKO小鼠脊髓运动神经元中NR1阳性斑点数也明显增多、增大。结论 神经元中p150glued缺失可以引起6月龄小鼠脊髓运动神经元中NMDA受体亚基NR1和NR2B增多。     

代谢型谷氨酸受体1阻滞剂LY367385对NMDA所致神经元损伤的保护作用

目的探讨代谢型谷氨酸受体1在神经系统兴奋性损伤中的作用。方法用代谢型谷氨酸受体1特异性阻滞剂LY367385预处理神经元细胞1 h,加入N-甲基-D-门冬氨酸(NMDA)造成兴奋性损伤;采用甲基噻唑基四唑(MTT)比色实验检测细胞活性; LDH试剂盒检测培养基中乳酸脱氢酶(LDH)活性;转移酶介导的三磷酸脱氧鸟苷-生物素刻痕末端标记(TUNEL)法检测细胞凋亡指数;免疫共沉淀和免疫印迹实验检测NMDA受体2B亚基(NR2B)和突触后致密物质95(PSD95)相互作用。结果 MTT、LDH和TUNEL实验显示,LY367385能减轻NMDA造成的神经元损伤(P 0. 05);免疫共沉淀和免疫印迹实验显示,NMDA受体与PSD95存在相互关系,LY367385可以减轻兴奋性损伤造成的NMDAR-PSD95表达增高(P 0. 05)。结论 LY367385能够明显减轻NMDA造成的神经元损伤,其机制可能与阻断代谢型谷氨酸受体1可以减少NMDA受体与PSD95连接相关。     

局灶性皮质发育不良皮质中NMDA受体亚基表达情况

目的探讨N-甲基-D-天冬氨酸(N-methyl-D-aspartate,NMDA)受体亚基NR1、NR2A、NR2B在难治性癫病人局灶性皮质发育不良(focal cortical dysplasia,FCD)皮质中的表达及意义。方法选取20例难治性颞叶癫(术后病理证实为FCD)为FCD组及10例颞叶血管畸形病人为对照组,收集两组病人术中切除的颞叶皮质,利用免疫组化和Syber Green荧光定量PCR技术检测标本中NMDA受体亚基NR1、NR2A、NR2B蛋白和mRNA的表达情况。结果对照组NR1、NR2A和NR2B蛋白表达分别为3.5、3、3,FCD组分别为5、5、5。对照组NR1、NR2A和NR2B mRNA表达分别为1.109、1.079、1.157,FCD组分别为2.176、2.324、2.348。与对照组比较,FCD组NR1、NR2A、NR2B蛋白和mRNA表达显著增加(均P<0.01)。结论 FCD皮质中NMDA受体亚基蛋白及mRNA表达升高,可能是FCD致机制之一。     

钙结合蛋白Calbindin在FMR1基因敲除小鼠脑组织中的表达

目的探讨脆性X综合征中钙结合蛋白Calbindin在神经元树突棘形态异常中的作用。方法我们选用FVB品系的FMR1基因敲除型(KO)和野生型(WT)小鼠,分别取新生1、3、5、7、10、14d,及成年(6周)的KO小鼠以及WT小鼠用免疫组织化学方法检测钙结合蛋白Calbindin在脑组织中的分布和表达情况,分别对大脑纹状皮质、海马、颞叶听区、梨状皮质、丘脑及小脑的免疫阳性显色细胞进行检测。结果在新生1d龄WT型及KO型小鼠中Calbindin免疫阳性细胞首先出现于梨状皮质和小脑皮质中,随着天龄的增长脑内其他各区逐渐出现Calbindin免疫阳性细胞的表达,且≤10dKO型小鼠Calbindin免疫阳性细胞平均光密度均显著高于WT型小鼠(P<0.05)。结论FMRP通过负性调节脑内钙结合蛋白Calbindin的表达,这推测与FMR1基因敲除小鼠神经元树突和树突棘形态异常有关。     

神经元型一氧化氮合酶的神经生物学研究进展(英文)

神经元型一氧化氮合酶(neuronal nitric oxide synthase,nNOS)主要表达于神经元,在星形胶质细胞和神经干细胞中也有一定水平的表达。不同的mRNA拼接形式产生了nNOS蛋白的5种亚型,包括nNOS- 、nNOS- 、nNOS- 、nNOS- 和nNOS-2。nNOS单体不具催化活性,二聚体是其活性形式。nNOS单体发生二聚化需要四氢生物蝶呤、血红素以及L-精氨酸的结合。nNOS的表达在很大程度上依赖于cAMP反应元件结合蛋白的活化,其催化活性的调节与热休克蛋白90/ 热休克蛋白70、钙调节蛋白、PIN 蛋白,以及自身Ser847和Ser1412位点的磷酸化和脱磷酸化相关。能与nNOS相互作用的蛋白主要有9种,包括突触后密度蛋白95(post-synaptic density protein 95, PSD95)、CALM、CAMKIIA、DLG4、DLG2、PFK-M、CAPON、syntrophin和dynein轻链。其中 PSD95、CAPON和PFK-M是神经元中最重要的 nNOS 调节蛋白。PSD95与nNOS 的相互作用能介导突触形成,并参与N-甲基-D-天冬氨酸诱导的神...     

大鼠脑缺血再灌注后血小板活化因子及其受体的病理作用

目的探讨血小板活化因子(PAF)及其受体(PAFR)在大鼠缺血再灌注后的病理性神经毒性作用及其可能的干预方法。方法选用SD大鼠建立一侧大脑中动脉缺血再灌注模型,于缺血再灌注后3h、6h、12h用高效薄层层析法测定大脑皮质缺血侧和缺血对侧PAF含量、RT-PCR检测PAFR基因表达。使用原代野生型小鼠皮质神经元细胞培养系统,将体外培养的神经元分为空白对照组、PAF组和PAF 拮抗剂组,应用碘化物/钙黄绿素染色分别检测各组细胞凋亡情况。结果缺血侧的大鼠皮质在缺血再灌注后3h、6h、12h PAF含量(单位为ng/g)分别为13·71±1·23、17·90±1·14和17·89±1·54;PAFR基因表达(单位为密度)分别为0·5892±0·1222、2·0512±0·1519、2·0168±0·1653,缺血再灌注6h、12h组缺血侧皮质PAF含量及PAFR基因表达与缺血对侧、再灌注3h比较差异有极显著性(均P<0·01);在进一步的体外小鼠皮质神经元细胞培养中,PAF组、PAF 受体拮抗剂组细胞凋亡率分别为(41·92±1·39)%和(18·94±1·18)%,与空白对照组[(10·23±0·59)%]比较差异有极显著性(均P<0·01),PAF 受体拮抗剂组细胞凋亡率与PAF组比较明显降低(P<0·01)。结论缺血性神经损伤作用是由PAF及其受体介导,用PAFR拮抗剂进行干预,对缺血缺氧性神经元损伤具有保护作用。     

脑源性神经营养因子基因转染可促进弥漫性轴突损伤神经元修复和轴突再生

应用脂质体将外源脑源性神经营养因子基因导入弥漫性轴突损伤模型大鼠脑内,力图通过脑源性神经营养因子促进神经元再生及修复的作用,促进损伤大鼠的形态功能恢复。结果显示基因转染后弥漫性轴突损伤额叶皮质神经元的形态得到改善,额叶皮质组织神经丝蛋白表达增加,证实脑源性神经营养因子可促进弥漫性轴突损伤后神经元的修复及轴突的再生。     

Epilepsy and anomalies of neuronal migration: MRI and clinical aspects

Neuronal migration disorders are the result of disturbed brain development. In such disorders, neurons are abnormally located. In diagnosing these conditions, magnetic resonance imaging is superior to any other imaging technique. This enables us to improve our knowledge of the clinical correlates of neuronal migration. With reference to migrational disorder, a retrospective study of all 303 patients with epileptic seizures referred for magnetic resonance imaging during a 3-year period was performed, 13 patients (aged 12-41, mean age 27) were identified. They represent 4.3% of the entire study group. Of the patients with known epilepsy, 6.7% and of the mentally retarded, 13.7% had migrational disorders. Four patients had schizencephaly as the dominant finding, one was classified as hemimegalencephaly, 2 had isolated heterotopias, and 6 had localized pachy- and/or poly-microgyria. The clinical pictures are complex. Ectopias of grey matter are recognised foci of epilepsy, but from an epileptological and a clinical viewpoint little attention has been given to these disorders. The present study shows that malmigration is not rare in epilepsy patients, especially not in the mentally retarded.     

Hepatic Considerations in the Use of Antiepileptic Drugs

Summary: Virtually all of the major antiepileptic drugs (AEDs) can cause hepatotoxicity, although fatal hepatic reactions are rare. The mechanisms, incidences, and risk profiles for such reactions differ from drug to drug. With carbamazepine and phenytoin, hepatotoxicity may be due to drug hypersensitivity. Although the profiles of patients at risk have not been well-defined for these two antiepileptic drugs, it would appear from reports in the literature that older adolescents and adults are at higher risk than children of developing serious or fatal hepatotoxicity. Once hepatotoxicity develops, mortality rates are 10–38% with phenytoin and 25% for carbamazepine. The risk profile for valproate fatal hepatotoxicity has been more clearly defined. Those at primary risk of fatal hepatic dysfunction are children under the age of 2 years who are receiving multiple anticonvulsants and also have significant medical problems in addition to severe epilepsy. The risk is considerably lower for patients over the age of 2 years on valproate monotherapy. In contrast to the risk profile with other AEDs, adults receiving valproate as monotherapy have the lowest risk of hepatotoxicity. Fatal hepatic dysfunction coincident with valproate may be the result of aberrant drug metabolism. Concomitant use of AEDs that induce microsomal P450 enzymes (e.g., phenytoin and phenobarbital) may enhance the production of a toxic metabolite, and hence the greater risk of hepatotoxicity with polypharmacy.     

Vascular Malformations and Epilepsy: Clinical Considerations and Basic Mechanisms

Summary: Vascular malformations (VMs) are associated with epilepsy. The natural history of the various VMs, clinical presentation, and tendency to provoke epilepsy determine treatment strategies. Investigations have probed the mechanisms of epileptogenesis associated with these lesions. Electrophysiologic changes are associated with epileptogenic cortex adjacent to VMs. Putative pathophysiologic mechanisms of epileptogenesis include neuronal cell loss, glial proliferation and abnormal glial physiology, altered neurotransmitter levels, free radical formation, and aberrant second messenger physiology.     

Classification of methods in transcranial Electrical Stimulation (tES) and evolving strategy from historical approaches to contemporary innovations

Transcranial Electrical Stimulation (tES) encompasses all methods of non-invasive current application to the brain used in research and clinical practice. We present the first comprehensive and technical review, explaining the evolution of tES in both terminology and dosage over the past 100 years of research to present day. Current transcranial Pulsed Current Stimulation (tPCS) approaches such as Cranial Electrotherapy Stimulation (CES) descended from Electrosleep (ES) through Cranial Electro-stimulation Therapy (CET), Transcerebral Electrotherapy (TCET), and NeuroElectric Therapy (NET) while others like Transcutaneous Cranial Electrical Stimulation (TCES) descended from Electroanesthesia (EA) through Limoge, and Interferential Stimulation. Prior to a contemporary resurgence in interest, variations of transcranial Direct Current Stimulation were explored intermittently, including Polarizing current, Galvanic Vestibular Stimulation (GVS), and Transcranial Micropolarization. The development of these approaches alongside Electroconvulsive Therapy (ECT) and pharmacological developments are considered. Both the roots and unique features of contemporary approaches such as transcranial Alternating Current Stimulation (tACS) and transcranial Random Noise Stimulation (tRNS) are discussed. Trends and incremental developments in electrode montage and waveform spanning decades are presented leading to the present day. Commercial devices, seminal conferences, and regulatory decisions are noted. We conclude with six rules on how increasing medical and technological sophistication may now be leveraged for broader success and adoption of tES.     

Carbamazepine Efficacy and Utilization in Children

Summary: Carbamazepine is effective for preventing partial and generalized tonic-clonic seizures in children. Although absence epilepsies are more common in children than adults, an estimated 80% of children with epilepsy have seizure types or epilepsies that are potentially responsive to carbamazepine. The differential diagnosis of ictal staring is an especially important issue in children because absence and atypical absence seizures are more prevalent in children than adults. Age-related pharmacokinetic differences and drug interactions are major considerations in children. On average, children have higher clearance rates of carbamazepine, shorter half-lives, and higher ratios of carbamazepine-10, 11-epoxide to carbamazepine than adults. In addition, children with severe epilepsy are more likely to require multiple-drug therapy, which can lead to complex drug interactions. When carbamazepine is administered along with valproate, drug protein binding interactions can cause intermittent side effects.     

Neonatal Seizures: Problems in Diagnosis and Classification

Summary: The clinical identification of neonatal seizures is critical for the recognition of brain dysfunction; however, diagnosis is often difficult because of the poorly organized and varied nature of these behaviors. Current classification systems are limited in their ability to communicate motor, autonomic, and electroencephalo-graphic features of seizures precisely and to provide a basis for uniform effective diagnosis, therapy, and determination of prognosis. Recent investigations of neonates, utilizing bedside electroencephalographic/polygraphic/ video monitoring techniques, have provided the basis for improved diagnosis and classification of seizures in the newborn. These studies have demonstrated that not all clinical phenomena currently considered to be seizures require electrocortical epileptiform activity for their initiation or elaboration. In addition, the specific clinical character of the phenomena considered to be seizures, the clinical state of the infant, and the character of the EEG indicate the probable pathophysiological mechanisms involved and suggest probable etiologies, prognosis, and therapy. Similarities between animal models that demonstrate reflex physiology and neonates with motor automatisms and tonic posturing suggest that these clinical behaviors may not be epileptic in origin but, rather, primitive movements of progression and posture mediated by brainstem mechanisms. Although not all clinical behaviors currently considered to be neonatal seizures may have similar pathophysiological mechanisms, they are clinically significant because they all indicate brain dysfunction.     

Valproate Monotherapy in the Management of Generalized and Partial Seizures

Summary: For decades, therapeutic tradition has promoted the concept of polypharmacy in the management of epilepsy. In recent years, however, studies have shown that, for most patients, monotherapy can provide comparable or better seizure control than administration of multiple anticonvulsants, while diminishing the potential for adverse reactions, drug interactions, and poor compliance. Valproate is an important monotherapeutic agent that is highly effective in the control of idiopathic primary and secondarily generalized epilepsies, and partial seizures that do not generalize. Comparative studies have found that valproate is at least as effective as phenytoin and carbamazepine in the treatment of generalized and partial seizures. Given the similar efficacy, other factors such as pharmacokinetics and side effects may therefore determine anticonvulsant selection for monotherapy.     

Un nouveau cadre conceptuel de travail pour la psychiatrie

In an attempt to place psychiatric thinking and the training of future psychiatrists more centrally into the context of modern biology, the author outlines the beginnings of a new intellectual framework for psychiatry that derives from current biological thinking about the relationship of mind to brain. The purpose of this framework is twofold. First, it is designed to emphasize that the professional requirements for future psychiatrists will demand a greater knowledge of the structure and functioning of the brain than is currently available in most training programs. Second, it is designed to illustrate that the unique domain which psychiatry occupies within academic medicine, the analysis of the interaction between social and biological determinants of behavior, can best be studied by also having a full understanding of the biological components of behavior.