人参皂甙Rd对颞叶癫大鼠学习记忆能力及海马5-HT表达的影响

目的研究人参皂甙Rd对氯化锂-匹罗卡品点燃颞叶癫(temporal lobe epilepsy,TLE)大鼠学习记忆能力及海马5-HT表达的干预作用。方法建立氯化锂-匹罗卡品点燃颞叶癫大鼠模型,将30只造模成功的颞叶癫大鼠随机分为TLE组(生理盐水10ml/kg腹腔注射,15只)及GSRd干预组(人参皂甙Rd2mg/kg腹腔注射,15只),另选15只大鼠作为正常对照组;采用Morris水迷宫及免疫组化染色分别检测各组大鼠学习记忆能力及海马5-HT表达水平。结果与正常对照组比较,TLE组大鼠学习记忆能力下降,海马5-HT表达明显减少(P0.05);与TLE组比较,GSRd干预组可显著提高大鼠学习记忆能力及海马5-HT的表达水平(P0.05)。结论人参皂甙Rd可能通过增加海马5-HT的表达来提高颞叶癫大鼠学习记忆能力。     

红藻氨酸诱导癫(癎)发作大鼠海马星形胶质细胞C-FOS基因表达的研究

目的研究癫发作大鼠海马星形胶细胞C-FOS基因表达的变化,探讨其对癫发作的维持与复发的影响。方法将83只成年雄性SD大鼠随机分为实验组58只,对照组25只。实验组在海马CA3区注射红藻氨酸(Kainicacid,KA)建立癫模型,对照组在相同部位注射等量生理盐水。利用免疫组织化学双重染色技术,分别在癫发作后1h、3h、6h、12h和24h观察大鼠海马星形胶质细胞C-FOS基因的表达。结果与对照组大鼠比较,癫模型鼠海马CA1区CFAP/C-FOS双标记阳性细胞百分率于癫发作后1h(12.70±0.03)、3h(17.10±0.05)、6h(24.92±0.04)明显升高(P<0.01),在6h达到高峰,在12h下降,但是仍较对照组高(10.71±0.06;1.59±0.02,P<0.01),在24h下降至对照组水平(2.00±0.02;2.08±0.03,P>0.05)。结论KA诱导大鼠癫发作,导致海马星形胶质细胞C-FOS基因相对持续的高表达,从而激活星形胶质细胞,产生高致性的病理环境,可能是癫发作的维持以及复发的病理生理机制之一。     

AG490对氯化锂-匹罗卡品致癫大鼠星形胶质细胞活化及癫的影响

目的探讨匹罗卡品致癫大鼠海马肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)的表达、星形胶质细胞活化及JAK/STAT信号转导通路在颞叶癫发作中的作用。方法应用腹腔注射氯化锂-匹罗卡品(PILO)的方法建立颞叶癫模型,应用JAK/STAT信号转导通路特异性抑制剂AG490进行腹腔注射建立干预模型组;用Western blotting方法测定大鼠海马匀浆后TNF-α表达水平的变化,用免疫荧光观察AG-490阻滞JAK/STAT通路后对大鼠海马TNF-α表达水平与星形胶质细胞活化及癫发作的影响。结果 (1)PILO致癫模型组有80.00%(32/40)的大鼠达Racine分级Ⅳ级以上发作;10.00%(4/40)的雄性大鼠死亡;10.00%(4/40)的雄性大鼠未达Racine分级Ⅳ级发作,模型成功率为80.00%;1月后有自发发作者8只(25.00%8/32)。AG490干预组雄性大鼠Ⅳ级以上发作的发生率为75.00%(30/40);病死率为7.50%(3/40);17.50%(7/40)的雄性大鼠未达Ⅳ级发作,模型成功率为75%;1月后有自发发作者1只(3.3%1/30),AG490组Ⅳ级及以上发作及自发发作数与PILO致癫模型组比较,有显著性差异(P<0.05);(2)PILO致癫模型组TNF-α表达水平较对照组开始增高,AG490干预组TNF-α表达水平均较PILO致癫模型组明显降低(P<0.05);(3)PILO癫模型组可见阳性颗粒在星形胶质细胞内的空间分布,AG490腹腔注射建立干预后阳性颗粒的星形胶质细胞明显减少(P<0.05)。结论癫发作后TNF-α表达水平明显增高,提示星形胶质细胞增生。AG490可阻断JAK/STAT信号转导通路进而抑制星形胶质细胞活化,同时也可以影响癫大鼠的行为学变化,提示AG490对癫的发作可能有一定的抑制作用,其机制可能与其抑制星形胶质细胞增生有关。     

发育期癫大鼠移植骨髓源性神经干细胞对海马BDNF和bFGF表达的影响

目的将骨髓源性神经干细胞(BMSCs)移植到发育期癫大鼠海马区,观察大鼠海马脑源性神经营养因子(BDNF)和碱性成纤维生长因子(bFGF)表达的变化。方法选择21日龄发育期大鼠,分离大鼠骨髓基质细胞,在特定条件下培养使其诱导分化为神经干细胞(NSC)。建立戊四氮(PTZ)点燃癫大鼠模型,将BMSCs经侧脑室注射移植至癫大鼠海马区;侧脑室注射磷酸缓冲液(PBS)作为对照。分为4组(均n=8):对照组(无癫发作),PTZ致组(癫造模,无治疗),假手术组(癫+PBS侧脑室注射),治疗组(癫+NSC侧脑室注射)。于3、7和14 d处理后用免疫组化法检测大鼠海马区BDNF和bFGF表达。结果致组大鼠海马区(齿状回、CA1区)BDNF和bFGF表达较对照组增加(P0.05),治疗组海马区(齿状回、CA1区)BDNF和bFGF表达较假手术组也有所增加(P0.05)。结论 BMSCs移植可以增加PTZ致大鼠海马BDNF和bFGF表达,从而发挥对癫后脑损伤的保护作用。     

银杏叶提取物对戊四氮致大鼠海马内NMDA受体和HSP70表达的影响

目的探讨银杏叶提取物抗癫的分子生物学机制。方法在SD大鼠腹腔内注射戊四氮(PTZ)诱发大鼠惊厥急性发作,制作癫模型。应用免疫组化技术观察银杏叶提取物(GBE)对点燃癫大鼠海马内NMDA受体和HSP70表达的影响。结果戊四氮致组大鼠海马内NMDA受体表达明显高于正常对照组,银杏叶提取物干预组明显低于戊四氮致组,银杏叶提取物干预组与正常对照组之间差异无显著性意义。戊四氮致组大鼠海马内HSP70表达明显高于正常对照组,银杏叶提取物干预组明显高于戊四氮致组。结论银杏叶提取物可降低癫大鼠海马内NMDA受体的表达,其可能通过此种机制来抑制癫的发生和发展。银杏叶提取物可增加癫大鼠海马内HSP70的表达,以此来减轻癫发作后所致的神经元损伤。     

颞叶癫(癎)大鼠海马轴突导向分子Sema3F及其受体Np2表达的变化

目的研究颞叶癫大鼠海马轴突导向分子Sema3F及其受体Np2表达的变化。方法给SD大鼠腹腔注射匹罗卡品、氯化锂制作颞叶癫模型。用免疫组化法和原位杂交技术对致后不同时间点大鼠海马CA1区、CA3区、齿状回的Sema3F mRNA、Np2 mRNA和蛋白表达进行检测,并与正常对照组比较。结果颞叶癫大鼠致后7d、15d,海马CA1区、CA3区Sema3F mRNA、Np2 mRNA和蛋白的表达明显低于正常对照组(P<0.05~0.01),致后30d、60d表达与正常对照组差异无统计学意义;而齿状回Sema3F mRNA、Np2 mRNA和蛋白的表达与正常对照组的差异无统计学意义。结论颞叶癫大鼠海马CA1区、CA3区Se-ma3F、Np2表达在致后早期明显下调,而在慢性期恢复正常。     

匹罗卡品癫幼鼠模型B1与B2激肽受体表达研究

目的检测B1及B2激肽受体在匹罗卡品癫幼鼠模型中表达的变化并探讨其作用机制。方法健康、雄性幼年(3周)SD大鼠35只,随机分为空白对照组5只;癫模型组15只,采用匹罗卡品法制作癫模型,分为急性期组、静止期组、慢性期组3亚组,每亚组5只;生理盐水对照组(盐水组)15只,与匹罗卡品实验组大鼠相同时间点给予腹腔注射盐水,分为与实验癫组各时间点相对应的盐水6h组、盐水5d组、盐水60d组3个亚组,每亚组5只。各组于相应时间点处死动物取海马标本,应用逆转录聚合酶链反应(RT-PCR)方法检测脑组织海马区的B1及B2激肽受体的表达变化,并相互比较。结果与盐水6h组、盐水5d组比较,急性期组、静止期组的B1激肽受体mRNA表达显著上调,差异具有统计学意义(P<0.05),慢性期与生理盐水60d组间比较差异无统计学意义(P>0.05);与盐水60d组比较,在实验癫模型各亚组B2激肽受体mRNA表达均显著上调,差异具有统计学意义(P<0.05);盐水各亚组与空白对照组相比,B1、B2激肽受体mRNA表达差异无统计学意义(P>0.05)。结论B1与B2激肽受体mRNA表达失衡在癫的发生、发展过程中起重要作用。     

小檗碱对癫痫大鼠脑组织P-糖蛋白表达的影响

目的 探讨小檗碱(BBR)对癫痫大鼠脑组织P-糖蛋白(P-gp)表达的影响.方法 将44只SD大鼠随机分为假手术组(9只)、癫痫组(9只)和BBR 10 mg/kg(9只)、20 mg/kg(9只)、40 mg/kg组(9只).采用大鼠海马注射海人酸方法制作癫痫模型,各BBR干预组分别于术前48 h、术前24h和术后6h腹腔注射相应剂量BBR.观察各组大鼠癫痫发作潜伏期及发作严重程度.造模24 h后,采用免疫组化方法检测并比较各组大鼠海马CA3区P-gp和核因子-κB(NF-κB) p65的表达水平.结果 BBR 20 mg/kg组[(66.11±5.90) min,(26.67±6.67) min]和40 mg/kg组[(76.33±9.11) min,(42.00±7.73) min]大鼠癫痫发作潜伏期及初次至第6次≥Ⅳ级痫样发作间隔时间均明显长于癫痫组[(41.78±10.45) min,(9.44±4.25)min](均P＜0.05).各组大鼠海马CA3区NF-κB p65和P-gp表达的差异均有统计学意义(H=16.024,H=21.830;均P＜0.01).癫痫组海马CA3区NF-κB p65和P-gp表达显著高于假手术组(均P＜0.05);BBR 20mg/kg和40 mg/kg组表达显著低于癫痫组(均P＜0.05).结论 BBR能够延长癫痫发作潜伏期、降低其严重程度,并抑制癫痫大鼠脑组织NF-κB和P-gp的表达.     

马桑内酯点燃癫(癎)大鼠海马及齿状回区CGRP变化的初步研究

目的了解马桑内酯(CL)点燃癫大鼠海马及齿状回降钙素基因相关肽(CGRP)表达变化,探讨其可能的作用及机理。方法健康雄性SD大鼠30只,随机分为2组:对照组(C组,n=6)和实验组(n=24)。实验组肌肉注射CL0.20ml/kg,次/60h,平均20次;24h内有3~5级(Racinescale)性发作,或连续2次注射期间发作10次或以上为点燃(K组),否则为未点燃(NK组);C组注射等量生理盐水。取各组脑组织行CGRP免疫组化染色,应用Image-proplus4.5图像分析系统检测其变化。结果11只大鼠点燃成功,K组CGRP表达较NK组和C组显著增强(P<0.05)。结论CL点燃癫诱发大鼠海马及齿状回CGRP表达明显增强,CGRP可能在CL点燃癫中发挥一定的作用。     

自发性癫痫大鼠脑内神经肽Y受体Y2R和Y5R的表达及分布

目的研究自发性癫痫大鼠(tremor rat,TRM)海马和颞叶皮质中神经肽Y(neuropeptide Y,NPY)Y2和Y5受体(Y2R和Y5R)的表达和分布。方法以TRM大鼠作为癫痫组,正常Wistar大鼠作为对照组,每组7只,以RT-PCR法检测Y2R和Y5R mRNA水平表达,Western Blot法检测其蛋白水平表达,免疫荧光法分析癫痫组和对照组大鼠海马CA1、CA3和齿状回(DG)区以及颞叶皮质中Y2R与Y5R的分布和定位。结果RT-PCR和Western Blot结果显示,与对照组大鼠相比较,癫痫组海马和颞叶皮质中Y2R mRNA相对表达水平(相对灰度值为海马:0.75±0.06 vs.0.51±0.07;颞叶皮质:0.70±0.05 vs.0.55±0.03)及蛋白相对表达水平(相对灰度值为海马:0.79±0.08 vs.0.42±0.05;颞叶皮质:0.72±0.05 vs.0.51±0.07)均显著上调(均P0.01),Y5R mRNA(相对灰度值为海马:0.52±0.10 vs.0.54±0.06;颞叶皮质:0.46±0.03 vs.0.42±0.04)及蛋白(相对灰度值为海马:0.28±0.06 vs.0.27±0.03;颞叶皮质:0.31±0.05 vs.0.27±0.07)表达均没有明显变化(均P0.05)。免疫荧光分析发现Y2R与Y5R在癫痫组大鼠海马CA1、CA3区神经元和DG区颗粒细胞以及颞叶皮质神经元中分布广泛且主要定位在细胞膜上。结论在TRM中Y2R表达在海马和颞叶皮质中均表达上调,但是Y5R的表达没有明显改变。     

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.     

Diagnostic Difficulties and Treatment Implications

Summary: Differentiation between types of epileptic seizures has been aided in recent years by the introduction of intensive neurodiagnostic techniques and the development of increasingly detailed classification systems. Paradoxically, these developments have not simplified the task of matching the appropriate antiepileptic drug to a particular seizure type. It is reasonable to assume that anticonvulsant drugs will have different effects on different types of seizures, but faulty, circular reasoning can enter the picture if one also assumes that responses of seizures to different drugs signify different seizure types. There are several examples of differential diagnoses that can fall prey to this problem, including the diagnosis between partial seizures with secondary generalization and generalized tonic-clonic seizures, and the diagnosis between complex partial seizures and absence seizures with automatisms, among others. Considerations of etiology in future classification systems can further complicate the problem: should one then choose an anticonvulsant drug on the basis of individual seizure type or on the basis of the type of epilepsy? Ramifications of this issue extend even to the drug approval process. Official sanction is not given for use of a drug for a seizure type not included in the original efficacy studies, even if later scientific evidence shows that seizure type to be related to a type that is included. New trials must be undertaken. These problems arise from how we choose to classify seizures.     

Cognitive Dysfunction Associated with Antiepileptic Drug Therapy

Summary: Epilepsy is frequently associated with cognitive dysfunction. However, the reasons for this correlation are unclear. Possible influential factors include patient age; duration, frequency, etiology, and type of seizures; hereditary factors; psychosocial issues; and antiepileptic drug (AED) therapy. Whereas many of these factors are beyond the physician's control, AED therapy is one element that can be addressed in treatment decisions by recognizing the potential cognitive effects of particular AEDs. For example, phenobarbital impairs memory and concentration; phenytoin affects attention, problem solving ability, and performance of visuomotor tasks. In contrast, carbamazepine may affect concentration, while valproate would appear to have minimal effects on cognition. Moreover, cognitive effects of AEDs are amplified with coadministration of multiple anticonvulsants (polytherapy). A review of studies on the cognitive effects of monotherapy with AEDs, as opposed to those of polytherapy, provides evidence that drug-related cognitive dysfunction can be reversed if patients are switched to a simpler therapeutic regimen. Future research should be directed toward developing reliable measures for assessing and monitoring cognition, and understanding the particular cognitive side effects of each AED. Physicians also need to revise their opinions about which side effects are "tolerable" for epileptic patients.     

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.     

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.     

Carbamazepine Efficacy in Adults With Partial and Generalized Tonic-Clonic Seizures

Summary: Carbamazepine and phenytoin are drugs of choice in initial monotherapy for adult partial and secondarily generalized tonic-clonic seizures. These designations reflect the results of the Veterans Administration Epilepsy Cooperative Study Group of 1985. An earlier comparative study of carbamazepine and phenytoin by Ramsay and associates found both drugs equally effective in controlling new-onset seizures. Among the advantages of carbamazepine is that it causes relatively few cognitive and dysmorphic side effects. Its disadvantages are its unavailability in parenteral formulation and its metabolic autoinduction. The latter must be compensated for by planned dosage increases to maintain therapeutic plasma steady-state levels during the first 2 or 3 months of treatment. Carbamazepine is judged a drug of choice in the treatment of these secondarily generalized tonic-clonic seizures, and the drug of choice in children, adolescents, and women susceptible to the dysmorphic side effects associated with other anticonvulsant agents.     

Etiologic and Preventive Aspects of Epilepsy in the Child–Bridging the Gap Between Laboratory and Clinic

Summary: Four broad categories of basic phenomena are pertinent to developing ways to prevent epilepsy. These include mechanisms of epileptogenesis, ictal initiation and temporary entrainment by the seizure discharge of normally functioning brain, seizure propagation, and control mechanisms that function both to restrain the cascade of epileptic events culminating in a seizure and to arrest the epileptic event and restore the interictal state. In newborns and children, hypoxia-ischemia is a major factor leading to epileptogenesis, and several schemes are proposed to classify, quantify, and prevent hypoxic-ischemic encephalopathy. Control mechanisms must be better understood in order to develop prophylactic recommendations for epilepsy, and an experimental model of "kindling antagonism" may increase our understanding of these. Programs of prevention of seizures in children will evolve only if basic researchers and clinicians work productively together to develop an adequate understanding of factors important in epileptogenesis and antiepileptogenic control mechanisms.     

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.     

Predisposing and Causative Factors in Childhood Epilepsy

Summary: We review information from large studies of defined populations, examining the role of known factors and especially of prenatal and perinatal factors in contributing to nonfebrile seizure disorders of early childhood. We depend especially, but not exclusively, on the recently completed analyses from the Collaborative Perinatal Project of the National Institute of Neurological and Communicative Disorders and Stroke, the NCPP. About 4% of children in the NCPP who had at least one non-febrile nonsymptomatic seizure by the age of 7 years had a previous seizure during acute neurologic illness, such as meningitis or during the acute illness after trauma. Many such seizures should potentially be preventable. Of children with seizures, 10% had had a neonatal seizure and 13% had had a febrile seizure. Among the hundreds of prenatal and perinatal factors explored as predictors of childhood seizure disorders, the principal predictors identified were congenital malformations of the fetus, cerebral and noncerebral; family history of certain neurologic disorders; and neonatal seizures. In agreement with the British National Child Development Study, labor and delivery factors in the NCPP appeared to contribute very little to childhood seizure disorders. Maldevelopment, rather than damage at birth to an initially intact nervous system, appeared to be the more common mechanism. Most seizure disorders of early childhood remained unexplained by the large set of prenatal and perinatal characteristics examined.