γ-氨基丁酸能神经元在新生大鼠缺氧性痫性发作中的作用

目的 通过观察新生大鼠早期发育过程中及缺氧性痫性发作后海马组织病理改变以及原癌基因c-fos蛋白、谷氨酸脱羧酶(glutamate decarboxylase,GAD)的变化,探讨γ-氨基丁酸(γ-amino butylic acid,GABA)能神经元在缺氧性痫性发作中的作用及可能的影响机制.方法 采用出生后10d的SD大鼠建立改良Jensen缺氧诱导痫性发作模型,分为痫性发作后1d、3d、7d、14d 4组,并选取相应时间点正常大鼠为对照组,采用尼氏染色方法检测海马组织的组织病理变化,免疫组织化学法检测各组海马c-fos蛋白灰度值以及GAD阳性神经元数量的改变.结果 尼氏染色结果显示,各缺氧性痫性发作组海马区形态结构正常,细胞排列略稀疏,但未见明显的细胞丢失.免疫组化结果显示,与对照组比较,c-fos蛋白灰度值在痫性发作后7d,在缺氧性痫性发作组海马CA2、CA3和DG区明显地降低(P ＜0.05);GAD阳性细胞数在痫性发作后7～ 14d,缺氧性痫性发作组海马CA1、CA3和DG区明显地减少(P＜0.05).结论 缺氧性痫性发作后14d内并没有造成大鼠海马区及时或迟发性细胞丢失,但c-fos表达在大鼠海马区有迟发性增高;缺氧性痫性发作后海马GABA神经元数量的减少可能是新生大鼠缺氧诱导痫性发作后癫痫易感性升高的原因之一.     

钙离子在癫痫发作中的作用机制

癫痫是一组慢性临床综合征,以在长期病程中有反复发作的神经元异常放电所致的短暂脑功能失常为特征。脑电图和微电极技术结合的研究证明,癫痫发作的电生理本质是脑神经元过度同步放电的结果。Heineman等在实验性癫痫中使用离子敏感微电极研究方法证实:癫痫发作时,细胞外钙离子(Ca~(2+))立即下降(从静息水平1.2～1.3降至0.1～0.9nmol),细胞内钙     

小胶质细胞在癫痫中作用的研究进展

正癫痫是神经元突发、异常、过度、同步放电引发的一种发作性脑功能障碍。癫痫发病机制十分复杂。研究发现神经炎症、氧化应激、免疫失调、神经元凋亡、自噬等因素,在癫痫发病过程中发挥重要作用。小胶质细胞是中枢神经系统的免疫效应细胞,参与将神经炎症、氧化应激、神经元凋亡、免疫调节等。本文就小胶质细胞在癫痫中的作用进行综述。1小胶质细胞的概述1.1小胶质细胞的类型与功能小胶质细胞外形和蛋白表达存在差异,不同条件激活的类型和功能状态也有差异[1]。小胶质细胞处于静息状态时体积较小,呈梭状,有树枝状分支;激活后,细胞体积变大,     

胶质细胞在癫痫发病机制中的作用研究进展

癫痫是神经系统疾病中的一种严重危害人类健康的常见病、多发病，患病率约为1％，发病机制非常复杂。胶质细胞是神经系统的重要组成部分，胶质细胞占脑细胞总数的约90％，包括星形胶质细胞、少突胶质细胞和小胶质细胞，其在生理与病理状态下对维护神经系统功能的作用至今未明。胶质细胞不仅与脑的正常生理活动、发育以及神经病理过程有明显关系，而且与神经元的功能活动以及损伤与修复过程有千丝万缕的联系。近年来研究表明胶质细胞在癫痫的发病机制中扮演重要角色。本文就痫性发作时胶质细胞功能改变（细胞形态改变、免疫表型改变和细胞增殖活动）、胶质细胞与神经元之间物质、信息交流方面的研究进展进行综述。     

小胶质细胞在癫痫发作状态中的研究进展

癫痫是一组由于脑部神经元异常过度放电引起的中枢神经系统疾病。小胶质细胞作为中枢神经系统的主要免疫细胞对神经的发育和维持起着重要作用。尽管研究报道,小胶质细胞可通过增加炎症介质等生物活性物质介导癫痫发作,但对于炎症介质相关的信号转导通路仍缺乏全面了解。此外,越来越多的证据证明,小胶质细胞在神经元变性、神经发生及突触修剪中发挥着至关重要的作用,这与癫痫的发生发展有关。因此,进一步研究小胶质细胞在癫痫发作过程中的生物学功能,明确小胶质细胞在癫痫中的分子机制,可为临床治疗癫痫提供新的分子靶点。 [国际神经病学神经外科学杂志, 2023, 50(6): 57-62]     

GAD在颞叶癫痫大鼠海马内源性促痫机制中的作用

目的:探讨GAD65、GAD67在颞叶癫痫发生后海马内源性促痫机制中的作用。方法:112只雄性SD大鼠随机分为实验组(n=70)与对照组(n=42),实验组大鼠选用海人酸腹腔注射法建立颞叶癫痫模型,对照组大鼠腹腔注射无菌生理盐水。选取腹腔注射后3小时、6小时、12小时、24小时、48小时、7天、30天为研究的时间点,颞叶海马的CA1区、CA3区、齿状回为研究部位。腹腔给药后每天观察大鼠的行为学变化,大鼠处死前进行EEG描记。用原位杂交方法检测不同时间点海马不同区域GAD65、GAD67mRNA的表达,免疫组织化学法检测GAD65、GAD67蛋白的表达。结果:实验组大鼠海马GAD65 mRNA及其蛋白的表达随时间呈逐渐增高趋势,致痫后48小时～30天,GAD65 mRNA及其蛋白表达较对照组增高(48小时P<0.05;7～30天P<0.01);海人酸致痫后6小时、24小时实验组大鼠海马的GAD67mRNA及其蛋白表达较对照组增高(分别为P<0.01、P<0.05)。结论:颞叶癫痫急性期海马GAD67表达的增高及慢性期海马GAD65表达的增高是癫痫发生后机体的内源性抗痫机制。     

Kalirin-7在癫痫突触发生机制中的作用研究进展

癫痫在神经系统疾病中很常见,其发病机制与兴奋性和抑制性神经递质功能紊乱、异常突触发生密切相关。Kalirin-7是Dbl癌基因家族Kalirin的主要同种型,受多种因子调节,在多个促进树突棘形成和突触发生的分子通路中起重要的介导作用,与突触发生密切相关。本综述通过对癫痫发生机制的简要介绍,以及Kalirin-7促进树突棘形成和突触发生发展的分析,为进一步研究癫痫的发生机制提供新的潜在依据和思路。     

应激在癫痫发病中的作用

近年来随着社会心理学的发展,应激作为癫痫的诱发因素日益为人们所重视。应激可引起心理、行为和生理等方面的反应,这些反应都可能是诱发癫痫的因素或内在机制所在。本文介绍了关于应激在癫痫发病中的作用的最新研究状况,以及缓解应激有助于预防和治疗癫痫的前景和展望。     

探讨GABAARG2基因在癫痫耐药机制中的作用

目的探讨癫痫患者中GABAARG2基因与耐药性癫痫的关系。方法选择来本院就诊的98例癫痫患者,根据对抗癫痫药物的反应性分为耐药组(观察组)46例和敏感组(对照组)52例进行研究,提取所有患者的DNA,采用PCR基因测序鉴定GABAARG2基因出现的概率,对每一位受试者以口服传统的抗癫痫药物-苯妥英(phenytoin)方式来对比两组患者的药物口服吸收率。结果观察组和对照组之间的年龄、性别、既往病史、持续状态方面差异均无统计学意义(P0.05)。观察组出现GABAARG2基因的概率显着高于对照组,差异具有统计学意义(χ~2=8.08,P=0.01);观察组的总体口服吸收率(68.71%±12.28%)明显低于对照组的口服吸收率(82.36%±15.31%),差异具有统计学意义(χ~2=6.78,P=0.01)。结论 GABAARG2基因的在脑内的出现会影响抗癫痫药物的效果,进而引起患者的耐药性,对临床治疗有较好的参考价值。     

钾离子通道在癫痫发病机制中的研究进展

癫痫的基本特征是中枢神经反复发作的同步异常放电,而神经元的异常放电与钾离子通道功能紊乱有密切的关系。钾离子通道编码基因突变以及其自身抗体表达异常可导致钾离子通道功能障碍,引发神经元异常放电,临床表现为多形式的癫痫发作。本文介绍了钾离子通道及其抗体在癫痫发病中的作用。     

Neonatal Caffeine Exposure and Seizure Susceptibility in Adult Rats

Summary: Early developmental exposure to caffeine in rats results in changes in brain excitability that persist to adulthood. The mechanism of these alterations is un- known. To identify potential neurotransmitter systems involved, we exposed neonatal rats to caffeine and determined seizure thresholds for chemoconvulsants active at different CNS receptors in the adult animal. Rats were unhandled (NH) or received by gavage (0.05 m1/10 g) either vehicle (water) or caffeine (15–20 mg/kg/day) for postnatal days 2–6.At age 70–90 days, each rat was infused intravenously (i.v.) with picrotoxin (PIC), bicucul-line (BIC) [convulsants acting at the γ-aminobutyric acid/ benzodiazepine (GABA/BDZ) receptor], pentylenetetra-zol [PTZ, possibly acting at both GABA/BDZ and N-methyl-D-aspartate (NMDA) receptors], caffeine (acting at adenosine receptors), strychnine (STR, acting at glycine receptors), or kainic acid (KA, acting at the NMDA receptor).Seizure thresholds were analyzed as a function of neonatal treatment and sex. Thresholds for caffeine, PTZ, PIC, and KA were increased as a function of neonatal caffeine exposure (p = 0.01, 0.02, 0.02, and 0.005, respectively).The thresholds for BIC and STR were not altered. There were also gender differences in seizure susceptibility. Thresholds for seizures produced by BIC, caffeine, PIC, and STR were higher in females (p = 0.005, 0.0005, 0.0001, and 0.0001, respectively), but were not different for seizures caused by PTZ. These results suggest that early developmental exposure to caffeine affects later seizure susceptibility. Moreover, some of these effects are gender specific.     

Neuronal Migration Disorders Increase Susceptibility to Hyperthermia-Induced Seizures in Developing Rats

Summary: Purpose: Retrospective studies suggest that adult patients with intractable epilepsy may have a history of febrile seizures in childhood. Risk factors for a febrile seizure may include the rate of increase in the core temperature (T-core), its peak (T_max), the duration of the temperature increase, or an underlying brain pathology. Recently, neuronal migration disorders (NMD) have been diagnosed with increasing frequency in patients with epilepsy, but the link between NMD, febrile seizures, and epilepsy is unclear. We studied rat pups rendered hyperthermic to ascertain the incidence of seizures, mortality, and extent of hippocampal cell loss in each group. Methods: We exposed 14-day-old rat pups with experimentally induced NMD (n = 39) and age-matched controls (n = 30) to hyperthermia (core body temperature >42°C). Results: The incidence of hyperthermia-induced behavioral seizures and mortality rate were significantly higher in rats with NMD than in controls (p < 0·05). The longer duration of hyperthermia resulted in a higher incidence of behavioral seizures and higher mortality rate (p < 0·05). In rats with NMD, hyperthermia resulted in hippocampal pyramidal cell loss independent of seizure activity; the extent of neuronal damage correlated positively with the duration of hyperthermia. In control rats, occasional neuronal loss and astrocytosis occurred only after prolonged hyperthermia. Conclusions: In immature rats, NMD lower the threshold to hyperthermia-induced behavioral seizures and hyperthermia in the presence of NMD may cause irreversible hippocampal neuronal damage.     

丰富环境促进颞叶癫(痫)大鼠神经发生及其机制的研究

目的 探讨丰富环境对颞叶癫(痫)大鼠齿状回新生细胞分化和存活的影响及其相关分子机制.方法 成年Wistar 大鼠随机分为4组:假手术组、丰富环境+假手术组、癫(痫)组、丰富环境+癫(痫)组,各组均n=15.大鼠侧脑室注射海人酸制作颞叶癫(痫)模型.丰富环境干预30 d后,应用免疫荧光技术观察大鼠海马齿状回的新生细胞分化和存活情况,用Western blot方法检测各组海马脑源性神经营养因子(BDNF)、cAMP应答元件结合蛋白(pCREB)、蛋白激酶A(PKA)表达水平.结果 丰富环境+假手术组、丰富环境+癫(痫)组齿状回新生细胞标记物(BrdU)和新生成熟神经细胞标记物(BrdU/NeuN)阳性细胞数分别多于假手术组、癫(痫)组(P＜0.05),而新生星形胶质细胞BrdU/GFAP阳性细胞数无统计学意义,并且丰富环境+假手术组、丰富环境+癫(痫)组海马BDNF和pCREB蛋白表达水平分别高于假手术组、癫(痫)组(P＜o.05),而PKA蛋白表达水平无增高.结论 丰富环境可能通过增强pCREB/BDNF通路促进成年颞叶癫(痫)大鼠海马齿状回的神经发生.     

氟桂利嗪对癫痫鼠痫性发作和脑电活动的影响

目的研究氟桂利嗪对青霉素致癎大鼠癎性发作和脑电活动的影响.方法用60只Wistar大鼠分4组,即对照组及氟桂利嗪10、20、40 mg·kg-1组,2 h后对照组和各实验组给同样剂量青毒素300 万U·kg-1腹腔注射,观察大鼠行为表现及EEG改变.结果氟桂利嗪能明显降低青霉素致癎大鼠癎性发作程度,明显缩短癎性发作持续时间,显著延长癎性发作的潜伏期,明显提高存活率;明显延长大脑皮质、海马癎性放电潜伏期,缩短其持续时间,明显减少癎性放电的数量.结论氟桂利嗪对青霉素致癎大鼠的癎性行为和大脑皮质、海马的癎性电活动均有抑制作用.     

The Effect of Spinal Cord Stimulation on Seizure Susceptibility in Rats

Objectives: Spinal cord stimulation (SCS) activates the thalamus, which may be involved in generation of seizures. SCS may therefore influence seizure susceptibility. We investigated the effect of SCS on seizure susceptibility when performed at low frequency (4 Hz) and a frequency in the typical range of SCS treatment (54 Hz). Materials and Methods: Rats were divided in three groups: control (N = 8), 4 Hz SCS (N = 6), and 54 Hz SCS (N = 8). Tonic‐clonic seizures were induced by 10‐min intravenous infusion of pentylenetetrazole (PTZ). SCS was started 5 min prior to PTZ infusion and continued for 5 min after infusion offset. Seizure susceptibility was accessed via the latency, number, and total duration of seizures. Results: Four Hz SCS significantly increased seizure susceptibility. Fifty‐four Hz SCS produced a nonsignificant trend toward decreased seizure susceptibility. Conclusions: Low‐frequency SCS is proconvulsive in rats. Further research needs to investigate if this also applies to humans.     

Clinical Indicators of Genetic Susceptibility to Epilepsy

Summary: We evaluated clinical indicators of genetic susceptibility to epilepsy in the families of 1,957 adults with epilepsy (probands) ascertained from voluntary organizations. Very few of the probands in this series had idiopathic epilepsy syndromes. Among relatives of probands with postnatal CNS insults, risks of epilepsy were no higher than in the general population. Risk was increased in relatives of probands without identified CNS insults (i.e., those with idiopathic/cryptogenic epilepsy) or with neurological deficit presumed present at birth, compared with relatives of probands with postnatal CNS insults. Among relatives of probands with idiopathic/cryptogenic epilepsy, risks were higher in parents and siblings, but not in offspring, of probands with generalized onset as compared with partial onset seizures. Risks in offspring were higher if the probands had onset of idiopathic/cryptogenic epilepsy before age 10 as compared with age 10 years, but risks in parents and siblings were not associated with the proband's age at onset. These results suggest that genetic susceptibility increases risk of some forms of cryptogenic epilepsy and of epilepsy associated with neurological deficit presumed present at birth, but not of postnatal symptomatic epilepsy. The influences on risk in offspring may differ from those in parents and siblings.     

Neonatal Maternally Deprived Rats have as Adults Elevated Basal Pituitary-Adrenal Activity and Enhanced Susceptibility to Apomorphine

Maternal deprivation of neonatal rats for 24  h enhances the adrenocortical response to stress and/or adrenocorticotropin hormone (ACTH) stimulation during the stress hyporesponsive period (SHRP). The present study tests the hypothesis that such maternally deprived neonatal male rats show altered hypothalamic-pituitary-adrenal (HPA) regulation not only immediately after deprivation but also in later life. In addition, we found previously that neonatal changes in HPA activity preceded modulation of nigrostriatal dopamine function. Therefore, we also measured dopamine responsiveness in adult rats which were deprived of their mother during infancy.     

A Prospective Study of Epilepsy Following Neonatal Convulsions

In a prospective study of 130 infants with neonatal convulsions, the frequency and type of epilepsy and the relationship between the presumptive etiology of neonatal convulsions and subsequent epilepsy were investigated in 82 survivors excluding those dying and lost to follow-up. Of these 82 children, 15 (18.2%) were found to have epilepsy, which was of generalized type in seven (8.5%), infantile spasm in four (4.9%), focal seizures in three (3.6%) and myoclonic seizures in one (1.2%). Febrile convulsions were noted in two children (2.5%). The presumed causes of neonatal convulsions were asphyxia, intracranial hemorrhage or neonatal meningitides in most instances, but no particular relationship was noted between the presumptive etiology of neonatal convulsions and the type of subsequent epilepsy. In 11 (73.3%) of the 15 epileptic children, concurrent mental retardation, cerebral palsy and postmeningitic hydrocephalus were noted. Evidence from RI cisternography, pneumo-encephalography and cerebral angiography indicated that perinatal or neonatal brain damage responsible for epilepsy might be organic in nature. The fact that epilepsy occurred later in many of cases of neonatal convulsions of unidentified etiology suggests that brain damage incurred during fetal life might also be implicated at least in some instances. The onset of epilepsy in this series was relatively early, invariably before three years of age.