苯乙酸对大鼠原代皮质神经元的毒性作用

探讨苯乙酸(phenylacetic acid,PAA)对大鼠原代培养的皮质神经元的毒性作用及其作用机制.实验结果显示,PAA加入无血清Neurobasal培养基可剂量依赖地损伤原代培养的皮质神经元,且干预培养的时间越长,神经元存活率越低.而同浓度(1.1×10-3mol/L)的PAA对皮质神经元的损伤明显高于海马.原代培养的皮质神经元补充一氧化氮合成酶抑制剂L--NAME、NMDA受体拮抗剂MR-801及I-型钙通道阻滞剂尼莫地平可显著地抵抗PAA的毒性作用.以上实验结果提示,PAA可选择性地损伤皮质神经元,其毒性作用可能与NO过量产生、兴奋性氨基酸的堆积及钙超载有关.     

苯乙酸对大鼠原代皮质神经元的毒性作用

探讨苯乙酸 (phenylacetic acid,PAA)对大鼠原代培养的皮质神经元的毒性作用及其作用机制。实验结果显示 ,PAA加入无血清 Neurobasal培养基可剂量依赖地损伤原代培养的皮质神经元 ,且干预培养的时间越长 ,神经元存活率越低。而同浓度 (1 .1× 1 0 -3mol/L)的 PAA对皮质神经元的损伤明显高于海马。原代培养的皮质神经元补充一氧化氮合成酶抑制剂 L- NAME、NMDA受体拮抗剂 MR- 80 1及 L型钙通道阻滞剂尼莫地平可显著地抵抗 PAA的毒性作用。以上实验结果提示 ,PAA可选择性地损伤皮质神经元 ,其毒性作用可能与 NO过量产生、兴奋性氨基酸的堆积及钙超载有关     

刺五加皂甙对谷氨酸毒性神经元凋亡的保护作用

目的观察神经元在谷氨酸毒性损伤时一氧化氮(NO)的动态变化及其与凋亡的关系,探讨刺五加皂甙(ASS)的有效保护浓度。方法采用谷氨酸(Glu)诱导的皮质神经元凋亡模型。随机分成Glu组、正常对照组及ASS3组;用流式细胞仪检测神经元凋亡率,用硝酸还原酶法测定细胞培养上清液中NO的含量,用MTT法测定神经元存活率并在电镜下观察细胞形态学变化。结果(1)Glu呈剂量和时间依赖性增加神经元培养液中NO含量,ASS能不同程度地减少NO含量;(2)与Glu共培养的神经元,其存活率呈剂量和时间依赖性下降,ASS能增加神经元存活率;(3)经Glu处理的神经元发生凋亡,细胞超微结构呈现凋亡样改变,其凋亡率与正常对照组比较有显著性差异(P<0.01)。ASS能减少Glu毒性神经元凋亡。结论NO介导了Glu毒性神经元凋亡,ASS可能通过抑制NO的释放及其神经毒性作用,拮抗Glu引起的神经元凋亡。     

缺氧预适应对体外培养神经元的神经保护作用存在一个时间窗

目的本实验采用体外培养皮质神经元研究缺氧预适应对谷氨酸损伤模型的保护作用,同时探索一定缺氧浓度下最佳保护作用的缺氧时间。方法原代培养神经元,确立谷氨酸损伤模型,对培养至第7天的细胞进行8%氧浓度和不同时间的缺氧预适应及谷氨酸损伤,用MTT法检测细胞的存活率。应用SPSS 17.0进行统计学分析。结果 8%O2缺氧4~8 h,皮质神经元谷氨酸损伤模型实验组与对照组相比,存活率提高,差异有统计学意义(P<0.05)。结论 8%O2缺氧4~8 h对谷氨酸损伤模型中的原代体外培养皮质神经元具有保护作用,该保护作用至少可持续6 h。     

谷氨酸受体抗体诱导海马神经元损伤的研究

目的:有研究发现谷氨酸受体(GluR)与难治性癫的发作相关,故研究GluR亚单位抗体(GluR3抗体)对海马神经元的损伤作用。方法:取SD新生鼠海马皮质组织,以此培养的原代海马神经元作为靶细胞。抗体在不同的作用时间(20和40h)和稀释倍数下,通过细胞存活率(MTT法)和乳酸脱氢酶(LDH)释放量来测定抗体对神经元的毒性;TUNEL染色法测定神经元的凋亡。结果:GluR3抗体对神经元具有细胞毒性和凋亡作用,并与抗体的滴度和作用时间呈剂量依赖性。即使在低滴度的情况下(×1000和×2000),此抗体仍可诱导凋亡,且与对照组比较差异有显著统计学意义(P<0.01,P<0.05)。结论:GluR3抗体的致机制可能与其能诱导神经元的损伤有关。     

单纯疱疹病毒1型感染对原代培养鼠皮质神经元凋亡caspase-3途径的影响

目的了解caspases-3在单纯疱疹病毒1型(herpes simplex virus type 1,HSV-1)感染原代培养鼠皮质神经元中对线粒体的调控作用以及与神经元凋亡的关系.方法用酶标仪检测体外培养小鼠皮质细胞正常组、病毒组、山梨醇组、山梨醇加病毒组、对照组在不同条件下caspase-3发光底物吸收值,测定caspase-3底物的含量.用流式细胞术结合TUNEL方法检测各组细胞凋亡情况及线粒体膜电位变化.结果加入底物后14 h测定A值:正常组为0.394 2、病毒1组为0.240 8、山梨醇组为0.539 2、病毒加山梨醇组为0.465 0,正常组caspase-3含量较阴性对照组增加,病毒组较正常组明显减低,山梨醇组较正常组明显增加,病毒加山梨醇组较山梨醇组减低.山梨醇及神经酰胺组细胞线粒体膜电位明显降低,而病毒组及病毒加山梨醇或神经酰胺组均无明显降低.结论正常体外培养的神经元存在细胞凋亡,病毒能够阻止线粒体膜电位的超极化,山梨醇诱导的神经细胞凋亡是依赖于caspase-3的细胞凋亡,HSV-1阻止依赖于caspase-3的细胞凋亡途径.     

JNK信号转导通路在Aβ25-35诱导大鼠原代海马神经元凋亡中作用机制的研究

目的 研究Aβ25-35诱导海马神经元凋亡的机制以及JNK抑制剂SP600125的保护作用，探讨在Aβ25-35细胞毒性中JNK-c-Jun信号转导通路的可能作用机制。方法 将体外海马原代神经元培养至第7天，用β淀粉样蛋白25-35片段(Aβ25-35)和JNK抑制剂(SP600125)对细胞进行处理。用光镜进行海马原代神经元形态学观察，MTT检测不同时间点的细胞活性，以及用免疫印迹法检测不同时间点的JNK及c-Jun蛋白活性。结果 大鼠原代海马神经元经过Aβ25-35处理后，发生凋亡，细胞生存率呈时间依赖性下降，经过免疫学方法检测发现细胞在Aβ25-35处理早期出现磷酸化JNK和磷酸化c-Jun的表达增高，且这一过程可被SP600125抑制。MTT检测发现在使用SP600125后，细胞生存率上升，具有显著性差异。结论 体外原代海马神经元培养实验表明Aβ25-35在诱导原代海马神经元凋亡过程中，c-Jun氨基端激酶(JNK)及其底物转录因子c-Jun被激活。使用JNK抑制剂SP600125后，JNK和c-Jun均被抑制，且海马原代神经元的生存率明显提高，生存状态明显改善。研究表明JNK信号转导通路可能促成Aβ的细胞毒性作用。     

亚低温下CIRP抑制H2O2诱导的大鼠皮层神经元凋亡

目的 探讨亚低温的脑保护作用是否是通过冷诱导RNA结合蛋白(CIRP)抑制神经元凋亡而发挥的.方法 分离培养原代大鼠皮质神经元,用CIRP-RNAi慢病毒转染神经元,100 μmol/L H2O2诱导神经元凋亡,按组分别放入37℃或32℃环境中培养,采用MTT比色法检测细胞存活率;应用Hoechst 33342染色、Annexin V-FITC标记法和流式细胞仪检测各组神经元的凋亡率;Western blot检测神经元细胞CIRP、Actived Caspase-3及TRX蛋白表达的变化.结果 在32℃环境中,皮质神经元内CIRP蛋白表达明显增加,Actived Caspase-3表达下调,TRX表达增加,神经元凋亡率为(4.5±0.8)％;与37℃环境下相比较,皮质神经元内CIRP蛋白表达明显减少,Actived Caspase-3表达显著增高,TRX表达下调,神经元凋亡率为(53.5±1.7)％,P＜0.05.结论 在亚低温环境中,CIRP蛋白在大鼠皮质神经元中表达增高,抑制H2O2诱导的神经元凋亡发生,发挥神经元保护作用,是亚低温的脑保护作用的途径之一.     

单纯疱疹病毒1型感染对原代培养鼠皮质神经元凋亡caspase-3途径的影响

目的 了解caspases-3在单纯疱疹病毒1型（herpes simplex virus type1,HSV-1)感染原代培养鼠皮质神经元中对线粒体的调控作用以及与神经元凋亡的关系。方法 用酶标仪检测体外培养小鼠皮质细胞正常组、病毒组、山梨醇加病毒组、对照组在不同条件下caspase-3发光底物吸收值，测定caspase-3底物的含量。用流式细胞术结合TUNEL方法检测各组细胞凋亡情况及线粒体膜电位变化。结果 加入底物后14h测定A值：正常组为0.3942、病毒1组为0.2408、山梨醇组为0.5392、病毒加山梨醇组为0.4650，正常组caspase-3含量较阴性对照组增加，病毒组较正常组明显减低，山梨醇组较正常组明显增加，病毒组较正常组明显减低，山梨醇组较正常组明显增加，病毒加山梨醇组较山梨醇组减低。山梨醇及神经酰胺组细胞线粒体膜电位明显降低，而病毒组及病毒加山梨醇或神经酰胺组均无明显降低。结论 正常体外培养的神经元存在细胞凋亡，病毒能够阻止线粒体膜电位的超极化，山梨醇诱导的神经细胞凋亡是依赖于caspase-3的细胞凋亡，HSV-1阻止依赖于caspase-3的细胞凋亡途径。     

癫痫发作大鼠海马神经元凋亡与caspase-3 mRNA表达的研究

目的 :研究癫大鼠海马神经元凋亡与caspase 3mRNA表达的关系。方法 :采用大鼠红藻氨酸 (KA)致模型 ,以原位末端标记 (TUNEL)检测癫后不同时间海马神经元凋亡 ;RT PCR检测caspase 3mRNA的表达。结果 :KA致后 1d ,海马CA1、CA3及CA4区开始出现凋亡细胞 ,3d时明显增多 ,7d时最多。KA致后 6h ,海马组织caspase 3mRNA表达显著增高 ,1、3、7d仍持续高水平表达。结论 :癫大鼠海马神经元凋亡与caspase 3mRNA的表达密切相关 ,caspase 3在神经元凋亡过程中起着重要的作用     

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.     

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.     

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.     

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.     

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.     

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.     

Special Pharmacokinetic Considerations in Children

Summary: Pediatric patients have greater degrees of pharmacokinetic variability and unpredictability than adults. This variability results from the effects of pharmacogenetics, age and growth, prior and current comedication, and disease. Newborns with seizures have the least predictable dosage requirements, and their needs change as drug-eliminating mechanisms mature in the neonatal period. Infants have the highest relative capacities to eliminate antiepileptics of any age group and require the largest relative doses. In addition to age-related trends, children demonstrate the same drug-specific, pharmacokinetic phenomena that adults do, including nonlinear phenytoin elimination, nonlinear valproate binding, and autoinduction of carbamazepine. Intercurrent illness and drug interactions further modify the age-related pharmacokinetic patterns in children and make dosage requirements even more unpredictable. Recent studies have shown that febrile illness can affect drug elimination, sometimes decreasing drug levels by 50% or more. Intermittent treatment with benzodiazepines administered either orally or rectally can be an important adjunct and help minimize this type of problem for children with marginally controlled epilepsy. Intermittent benzodiazepines are also helpful for children who have febrile seizures and who need only occasional antiepileptic protection.