β-细辛醚对谷氨酸诱导损伤的脑皮层神经元凋亡线粒体膜电位和超微结构的影响

目的探讨β-细辛醚对谷氨酸(Glu)诱导损伤的脑皮层神经元凋亡、线粒体膜电位(mitochon-drial membrane potential,MMP)和超微结构的影响。方法体外培养乳鼠脑皮层神经元,β-细辛醚(7.5、15、30μg/ml)预给药4h,荡洗后加入终浓度为40mmol/L的Glu继续培养16h,采用流式细胞仪检测细胞凋亡率、MMP,并用透射电镜观察超微结构的变化。结果40mmol/L Glu组凋亡率明显增加(P<0.01),7.5、15、30μg/mlβ-细辛醚均能不同程度地抑制皮层神经元凋亡,30μg/mlβ-细辛醚抑制神经元凋亡的作用较7.5、15μg/mlβ-细辛醚明显(P<0.01),10μmol/L尼莫地平与30μg/mlβ-细辛醚抑制凋亡的作用相当(P>0.05);40mmol/L Glu组MMP明显低于正常对照组(P<0.01),10μmol/L尼莫地平组和30μg/mlβ-细辛醚组MMP明显高于40mmol/LGlu组(P<0.05,P<0.01),而与正常对照组比较无明显差别(P>0.05);电镜下40mmol/LGlu组的脑皮层神经元见染色质边聚、线粒体肿胀、部分内质网扩张,而30μg/mlβ-细辛醚组神经元则仅见少量内质网扩张、线粒体轻度肿胀。结论β-细辛醚可抑制Glu诱导的脑皮层神经元凋元,其作用机制可能与稳定细胞线粒体膜电位有关。     

神经生长因子对糖皮质激素诱导大鼠海马神经元凋亡的保护作用

目的探讨神经生长因子对糖皮质激素诱导的大鼠海马神经元凋亡的保护作用。方法体外分离原代培养18只新生Wister大鼠海马神经元,噻唑蓝法测定地塞米松诱导海马神经元凋亡的最低敏感剂量,观察不同质量浓度神经生长因子对地塞米松(0.10×10~(-6)mol/L)诱导海马神经元凋亡的保护作用。结果与阴性对照组相比,地塞米松Ⅰ组(10×10~(-6)mol/L)、Ⅱ组(1×10~(-6)mol/L)和Ⅲ组(0.10×10~(-6)mol/L)大鼠海马神经元活性均降低(P=0.000,0.000,0.000)。予不同质量浓度神经生长因子后,神经生长因子0.18 ng/ml组大鼠海马神经元活性低于阴性对照组(P=0.000)和阳性对照组(P=0.010),神经生长因子18 ng/ml组大鼠海马神经元活性高于阳性对照组(P=0.000)和神经生长因子0.18 ng/ml组(P=0.000)。结论糖皮质激素可以诱导体外培养的大鼠海马神经元凋亡,地塞米松0.10×10~(-6)mol/L是诱导海马神经元凋亡的最低敏感剂量,神经生长因子可以拮抗地塞米松诱导的大鼠海马神经元凋亡。     

内皮素-1诱导培养大鼠大脑皮质神经元凋亡的初步研究

目的观察内皮素(endothelin,ET)-1有无直接诱导原代培养神经元凋亡的作用,以及其作用通过的ET受体亚型。方法神经元培养取自新生SD大鼠大脑皮质。培养5 d后分别加入0.2 nmol/L,20 nmol/L ET-1处理24 h,用Annexin V、Hoechst 33258染色半定量测定细胞凋亡。再用流式细胞仪分别定量检测ET受体A拮抗剂(BQ123)或ET受体B拮抗剂(BQ788)对20 nmol/L ET-1诱导神经元凋亡的效果。结果0.2 nmol/L ET-1未显示诱导培养神经元凋亡的作用;20 nmol/L ET-1处理后24 h,培养神经元凋亡率明显高于对照组(P<0.01);BQ123和BQ788分别部分阻断了20 nmol/L ET-1诱导神经元凋亡的作用(P<0.01),但阻断效果不完全。结论20 nmol/L ET-1可直接诱导培养大鼠大脑皮质神经元凋亡,其作用可能是通过其A受体和B受体亚型共同实现的。     

刺五加多糖对H_2O_2损伤的海马神经元表达NF-κB的影响

目的研究刺五加多糖(ASPS)对氧化应激损伤的海马神经元表达核转录因子-κB(NF-κB)的影响,进一步探讨ASPS对海马神经元的保护作用。方法从新生大鼠脑分离海马,其神经元经原代培养后分为阴性对照组、损伤模型组(1 mmol/LH_2O_2诱导)、ASPS干预组(该组按ASPS10、5、2.5μg/ml的终浓度又分为3个亚组)。采用H_2O_2复制海马神经元氧化应激损伤模型。用免疫组化法和逆转录PCR法检测NF-κB的表达。同时观察各组海马神经元的形态学变化。结果与损伤模型组比较,ASPS干预组神经元损伤程度明显减轻。NF-κB在10μg/ml和5μg/ml ASPS干预组中的表达水平明显降低。结论 ASPS能明显减少受损海马神经元NF-κB的表达,对海马神经元有明显的保护作用。     

天麻素对海人酸致大鼠大脑皮质神经元损伤的保护作用

目的 探讨天麻素对海人酸致大鼠大脑皮质神经元损伤的保护作用及可能机制.方法 提取新生大鼠大脑皮质神经元体外培养,7d后随机分为对照组、海人酸模型组、不同浓度天麻素干预组(12.5、25、50mg/L);采用倒置相差显微镜观察神经元形态学变化,AO/EB荧光染色检测神经元凋亡,LDH活性测定检测胞膜稳定性,CY3荧光染色检测EphA4表达变化.结果 与海人酸模型组相比,各天麻素干预组神经元凋亡率、LDH活性显著下降(P<0.01),EphA4表达上调显著受抑(P<0.01),以25mg/L天麻素效果最明显.结论 天麻素对海人酸诱导大鼠大脑皮质神经元损伤具有保护作用,以中浓度效果最佳,可能与抗凋亡、稳定细胞膜、抑制细胞活化蛋白EphA4的表达上调等因素相关.     

脑苷肌肽促进星形胶质细胞分泌GDNF保护AAPH诱导神经元损伤的实验研究

目的研究脑苷肌肽对缺血性卒中患者发挥神经保护作用的可能机制,探讨星形胶质细胞在脑保护中的作用。方法取10只孕16~18 d SD大鼠的胚胎、及10只24 h SD乳鼠的脑组织分别用于原代神经元及原代星形胶质细胞培养,经免疫组化染色证实培养的细胞分别为神经元和星形胶质细胞后,给予1 mmol/L、5 mmol/L、10 mmol/L、20 mmol/L和40 mmol/L 2,2-偶氮二(2-甲基丙基咪)二盐酸盐{2,2’-Azobis[(2-methylpropionamidine)dihydrochloride,AAPH]}模拟缺血性卒中诱导神经元和星形胶质细胞损伤,并通过利用分光光度计分析细胞活力,观察AAPH对细胞活力的影响;观察0.025μg/ml、0.05μg/ml和0.1μg/ml脑苷肌肽对星形胶质细胞的保护作用,同时制备脑苷肌肽-星形胶质细胞条件培养基,比较条件培养基对AAPH诱导的神经元损伤的保护作用。结果经分光光度计分析40 mmol/L AAPH为合适诱导损伤浓度,在AAPH损伤4 h后,分别给予不同浓度的脑苷肌肽共同孵育24 h。结果显示0.025μg/ml、0.05μg/ml和0.1μg/ml浓度的脑苷肌肽均能够减轻AAPH造成的星形胶质细胞损伤,但0.05μg/ml和0.1μg/ml的脑苷肌肽的保护作最为显著。0.1μg/ml脑苷肌肽-星形胶质细胞条件培养基能够通过促进胶质细胞分泌胶质源性神经生长因子,进而保护AAPH诱导的神经元损伤(P0.05)。而将0.1μg/ml的脑苷肌肽作用24 h后的细胞上清液作为条件培养基,在40 mmol/L AAPH诱导神经元损伤后加入脑苷肌肽-星形胶质细胞条件培养基作用24 h。检测神经元细胞活力,发现脑苷肌肽-星形胶质细胞条件培养基能够逆转AAPH造成的神经元损伤,差异具有显著性(P0.05)。结论脑苷肌肽作为临床常用的神经保护剂,其可能的作用机制之一是促进星形胶质细胞分泌胶质源性神经生长因子,发挥神经保护作用。     

苯妥英对缺氧大鼠大脑皮质神经元钙激活钾通道的影响

目的 :研究苯妥英对缺氧大鼠大脑皮质神经元钙激活钾 [K(Ca) ]通道的影响。方法 :应用膜片钳单通道技术记录苯妥英对缺氧大鼠大脑皮质神经元上K(Ca)通道电流活动。电流信号经放大、滤波及转换后输入微机进行采样、储存和分析。结果 :苯妥英对缺氧大脑皮质神经元K(Ca)通道具有明显的激活作用 ,主要是增加通道的开放概率 (openprobability,Po)。结论 :苯妥英激活大脑皮质神经元K(Ca)通道 ,产生超极化电位 ,从而稳定细胞膜 ,降低细胞兴奋性 ,延缓缺氧除极的发生 ,这可能是苯妥英抗缺血脑损伤的另一个重要机制     

促红细胞生成素对新生大鼠皮质神经元体外缺氧缺糖损伤的保护作用研究

目的研究rhEPO对新生大鼠皮质神经元氧糖剥夺(OGD)损伤的保护作用及rhEPO的作用剂量及作用时间。方法新生Wistar大鼠皮质神经元原代培养7 d~11 d,随机分为正常对照组、OGD损伤组和rhEPO处理组。(1)建立皮质神经元的OGD模型,给予不同剂量的rhEPO(0.1、1、10、100 U/ml);(2)在不同时间(OGD损伤后0 h、24 h、48 h)给予10 U/ml rhEPO。观察各组细胞形态学改变,MTT法检测细胞存活率。结果与OGD损伤组比较,rh EPO(0.1、1、10 U/ml)处理可增加OGD损伤的皮质神经元的存活率(P0.05),且浓度为10 U/ml时rhEPO保护作用最强(P0.05)。皮质神经元OGD损伤后立即加入rhEPO(10 U/ml)保护作用最强(P0.05),损伤后24 h及48 h给药没有增加皮质神经元存活率。结论 rhEPO对体外缺氧缺糖损伤的大鼠皮质神经元具有保护作用,rhEPO有效浓度为0.1~10 U/ml,且其浓度为10 U/ml时保护作用最强;rhEPO在神经元损伤后立即给药保护作用最强。     

亚低温3 h可抑制新生大鼠缺氧缺血性脑细胞凋亡的影响

实验建立缺氧缺血性脑损伤新生大鼠模型,于缺血缺氧后立即采用31 ℃亚低温分别持续3,6,15 h进行全身干预,原位末端标记技术标记显示大鼠大脑皮质、海马、室周白质的凋亡细胞数减少,免疫组织化学法检测的细胞凋亡相关蛋白bcl-2和细胞周期调节相关蛋白p16表达降低,综合比较全部结果数据显示,且以亚低温干预3 h细胞凋亡抑制效果最佳,其次是亚低温干预6 h,而亚低温干预15 h可出现大脑皮质神经元细胞数降低的不良反应。结果证实,31 ℃亚低温干预可通过抑制细胞凋亡的方式对缺氧缺血性脑损伤组织起保护作用,3 h为最佳干预时间。     

大鼠酒精中毒后大脑皮质、海马、小脑的病理学改变及caspase-3的异常表达

目的探讨大鼠慢性酒精中毒后大脑皮质、海马、小脑的病理学改变及caspase-3的异常表达。方法选用健康雄性Wistar大鼠随机分为两组,其中酒精中毒组30只;盐水对照组20只。酒精中毒组每日每只大鼠分别按8ml/kg灌胃2w,随后再按照10ml/kg灌胃1w,按12ml/kg灌胃1w,共灌胃4w。每日灌胃两次,其间隔均为6h,酒精浓度为50%。对照组用等量的生理盐水灌胃。并对两组大鼠进行体重、一般生物学特征、HE染色、TUNEL染色、免疫组化caspase-3的检测。结果造模成功后,两组大鼠的体重存在的统计学差异;HE染色后酒精组大鼠大脑皮质、海马、小脑锥体细胞数目减少,部分神经元变性、坏死;TUNEL法测定酒精组大鼠凋亡细胞数量明显多于对照组(P<0.05),酒精组大鼠大脑皮质、海马、小脑的caspase-3表达明显高于对照组(P<0.05)。结论慢性酒精中毒可引起大鼠大脑皮质、海马及小脑的病理学改变,出现神经细胞凋亡,引起与凋亡相对应部位caspase-3阳性表达,并参与大鼠酒精中毒后凋亡机制的发生、发展。     

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.