戊四氮致癫痫状态对大鼠长期行为和脑电的影响

目的 建立一种戊四氮（ＰＴＺ）致癫痫状态（ＳＥ）模型,并探讨ＰＴＺ致惊厥与癫痫形成之间的关系。方法 观察ＰＩＺ致抽搐发作（抽搐组）和ＰＴＺ致抽搐延长发作即癫痫状态（ＳＥ组）对大鼠长期行为和脑电（ＥＥＧ）的影响,同时观察二者是否产生海马、皮质神经元损伤。结果 ＰＴＺ致抽搐延长发作能够产生具有某些癫痫特征的长期效应,如自发痫样放电、惊厥阈下剂量ＰＴＺ可诱导癫痫发作以及皮质和海马神经元损伤,而单次抽搐发     

去势对戊四氮点燃大鼠癫痫模型的行为学表现

目的 研究去势对戊四氮点燃大鼠癫痫模型行为学表现的影响.方法 采用戊四氮腹腔注射制作癫痫大鼠模型,对照研究去势大鼠同正常大鼠的潜伏期及持续时间等行为学表现.结果 大鼠癫痫模型全部点燃,去势组平均潜伏期(8.09±0.89) min((-x)±SD)长于非去势组的(3.94±0.65) min((-x)±SD).发作时间也有所缩短,去势组(19.16 ±3.06) min((-x)±SD)略短于非去势组的(26.37±2.90) min((-x)±SD) (P ＜0.05).非去势组点燃时间明显短于去势组,非去势组平均点燃时间(20.83±6.15) d((-x)±s),而去势组平均点燃时间(24.6±5.64) d((-x)±SD).结论 戊四氮点燃大鼠致痫模型是一种成熟的、较为安全的癫痫模型.去势后,SD雄鼠较正常非去势SD雄鼠相比致痫潜伏期延长、持续时间缩短、发作频率及程度减轻,点燃时间也明显长于正常SD雄鼠.     

海马神经细胞活化在戊四氮点燃大鼠癫痫形成过程中的作用

目的 以核因子κB/P65(nuclear factor κB,NF-κB/P65)的核转位作为神经细胞活化的标志,观察在戊四氮(pentylenetetrazol,PTZ)点燃大鼠出现惊厥之前,即点燃过程中海马神经细胞NF-κB活化在癫痫形成过程中的作用.方法 将大鼠随机分为对照组、非药物干预组、药物干预组(苯巴比妥30 mg/kg, 腹腔注射,每日一次).除对照组外均以低于急性致惊剂量的PTZ(40mg/kg,腹腔注射,每日一次)点燃大鼠,用行为学观察和脑电图确定癫痫存在,免疫组织化学方法 检测大鼠癫痫形成过程中不同时间点海马CA各区和齿状回神经细胞NF-κB活化,用图像分析系统分析对照组、非药物干预组和药物干预组三大组间海马神经细胞NF-κB活化的差异.结果 非药物干预组大鼠均于17d～22d点燃,而药物干预组PTZ点燃大鼠所需时间明显延长(于30d～35d点燃),且行为学惊厥程度和脑电痫样放电明显轻于非药物干预组.非药物干预组大鼠在行为学未出现惊厥,脑电图未出现痫样放电的点燃前潜伏期内,其海马CA各区、齿状回NF-κB活化的阳性神经细胞数明显增加,与对照组相比两者有显著性差异(P<0.05);药物干预组在与非药物干预组相应时间点的海马CA各区、齿状回NF-κB活化的阳性神经细胞明显减少,两者有显著性差异(P<0.05).结论 海马神经细胞活化是PTZ点燃大鼠癫痫形成的重要机制之一,苯巴比妥可通过抑制神经细胞活化,预防癫痫发生.     

戊四氮点燃癫痫持续状态大鼠海马p53的表达

目的观察癫痫持续状态后不同时间的大鼠海马神经细胞p5的表达变化,探讨p53基因在癫痫发作后的凋亡调控机制。方法戊四氮腹腔注射诱导大鼠癫痫持续状态（SE）,观察大鼠行为学改变,并选取SE后1、6、24、48、72h共5个时间点运用反转录多聚酶链反应（RT—PCR）、Western Blot方法检测SE组和对照组大鼠海马p53的表达。结果SE后6h,p53表达开始增高（P〈0．05）,24h达高峰（P〈0．001）,48h略有下降（P〈0．05）,72h后下降明显（P〈0．01）,但仍高于对照组水平。各组间两两比较差异有统计学意义（P〈0．05）。结论p53基因对戊四氮诱导癫痫持续状态后大鼠神经细胞凋亡起重要作用。     

戊四氮点燃大鼠中海马谷氨酸转运体的作用研究

目的 研究点燃形成过程中和点燃后谷氨酸转运体的变化,进一步探讨慢性癫痫的点燃机制。方法 将78只雄性成年Wistar 大鼠随机分为对照组（I组）和戊四氮（PTZ）组（Ⅱ组）。Ⅱ组腹腔注射阈下剂量的PTZ（35mg/kg),每日1次,直至达到点燃标准;Ⅰ组腹腔注射等量生理盐水。采用逆转录聚合酶链式反应（RT－PCR）方法检测海马区谷氨酸转运体－1（GLT－1）mRNA和兴奋性氨基酸载体－1（EAAC1）mRNA的表达。结果 GLT－1mRNA的表达在0h、48h时显著升高,随后下降;EAAC1mRNA的表达呈上升趋势。点燃后第60d时,基本恢复至对照组水平。结论 海马区GLT－1的下降和EAAC1的升高可能与癫痫敏感性的形成与维持有关。     

尼莫地平对癫痫大鼠学习记忆及海马超微结构的影响

目的探讨尼莫地平(nimodipin,NIM)对戊四氮(pentylenetetrazol,PTZ)点燃癫痫大鼠学习记忆能力及海马CA3区超微结构的影响。方法动物分为正常对照组、PTZ组和NIM PTZ组,采用PTZ慢性点燃癫痫模型,应用Morris水迷宫观察各组大鼠空间学习记忆能力,电镜观察海马CA3区突触界面结构,并对突触活性参数量化分析。结果PTZ点燃癫痫大鼠存在学习记忆能力下降,其海马CA3区突触后致密物显著变薄、突触小泡显著减少、突触间隙显著增宽(P<0.05);尼莫地平能改善癫痫大鼠学习记忆障碍,与PTZ组比较,突触后致密物增厚、突触小泡增多、突触间隙变窄(P<0.05)。结论PTZ点燃癫痫大鼠存在空间学习记忆受损,可能与突触界面参数改变有关;NIM可以改善癫痫大鼠突触超微结构,提高学习记忆能力。     

柴胡总皂甙对戊四氮慢性点燃大鼠海马谷氨酸细胞的影响

目的研究柴胡总皂甙对戊四氮(PTZ)慢性点燃癫痫模型大鼠海马区谷氨酸(Glu)阳性细胞表达的影响。方法48只健康SD大鼠被随机分为6组,即空白组(A组)、生理盐水组(B组)、丙戊酸钠(VPA)组(C组)和柴胡总皂甙高、中、低三种剂量组(D组、E组、F组),每组8只,除A组不做处理外,其他各组采用腹腔注射PTZ慢性点燃造模,造模同时给予VPA、柴胡总皂甙等不同处理因素,连续4周后取脑组织切片进行Glu免疫组化染色,从阳性细胞数、灰度值分析结果。结果在CAl区,B组海马阳性细胞数高于A、C、D、E、F组,有显著性差异(P＜0．05),B组海马各区阳性细胞灰度值低于其他各组,与A、C、D各组比较,有显著性差异(P＜0．05)；而在CA2区和DG区,B组阳性细胞数、灰度值与各组差异无统计学意义。结论柴胡总皂甙可以影响PTZ点燃大鼠海马CA1区的Glu表达水平,从而抑制PTZ慢性点燃大鼠的痫性发作。     

睾酮对戊四氮致大鼠行为学及脑电图变化的影响

目的探索睾酮(testosteron,T)在戊四氮致大鼠癫发作中的作用。方法观察正常致A组、阉割致B组、阉割后加小剂量睾酮致C组及阉割后加大剂量睾酮致D组大鼠行为学及脑电图的变化。结果行为学B组的潜伏期较A组、C组及D组明显缩短(P<0.05),D组的潜伏期较C组明显延长(P<0.05)。B组的重型发作程度亦较A组明显(P<0.05);脑电图B组的波潜伏期较A组、C组及D组明显缩短(P<0.05),D组的潜伏期较C组明显延长(P<0.05)。B组的波频度较A组、C组及D组明显增多(P<0.05)。B组的波总变异(TV)变化百分比较A组、C组及D组明显增大(P<0.05),D组的TV变化百分比较C组明显减小(P<0.05)。结论睾酮具有一定的抗作用,且大剂量更加明显。     

戊四氮点燃大鼠海马CA3区钙超载与亚低温对点燃大鼠脑保护作用的研究

目的 海马CA1区钙超载是否在癫痫的发病机制中起主要作用及亚低温对癫痫是否有治疗意义。方法用荧光倒置显微镜来测定癫痫状态下海马CA1、CA3区钙超载的情况，并用钙离子拮抗剂尼莫地平作用于海马脑片看钙超载的变化。然后将大鼠分为头皮温度为41℃、37℃、32℃、26℃的4组，通过对4组点燃大鼠行为学和海马组织病理学的观察来看亚低温对癫痫的脑保护作用。结果癫痫大鼠海马CA1，CA3区钙超载高于对照组．CA1区钙超载高于CA1区。在尼莫地平的作用下CA1区钙超载明显降低。组织病理学改变显示CA1区是海马区神经元变性、坏死最明显的部位。而亚低温下癫痫的发作程度和神经元变性、坏死最轻。结论钙超载参与了癫痫的发病机制，其中海马CA3区的钙超载在癫痫发病机制中起主要作用。而亚低温对脑有保护作用。     

戊四氮点燃慢性癫痫大鼠海马及颞叶皮质γ-氨基丁酸转运体1及胶质纤维酸性蛋白的表达

BACKGROUND： Gamma-aminobutyric acid transporter plays an important role in gamma-aminobutyric acid metabolism, and is highly associated with epilepsy seizures. Pathologically, astrocytes release active substances that alter neuronal excitability, and it has been demonstrated that astrocytes play a role in epileptic seizures. OBJECTIVE： To observe changes in gamma-aminobutyric acid transporter 1 and glial fibrillary acidic protein expression in the hippocampus and cortex of the temporal lobe in rats with pentylenetetrazol-induced chronic epilepsy. DESIGN, TIME AND SETTING： Randomized, controlled, animal experiment was performed at the Department of Neurobiology, Third Military University of Chinese PLA between January 2006 and December 2007. MATERIALS： Pentylenetetrazol was purchased from Sigma, USA; rabbit anti-rat gammaaminobutyric acid transporter 1 and glial fibrillary acidic protein were from Chemicon, USA. METHODS： A total of 40 Sprague Dawley rats were divided into model and control groups. Rat models of chronic epilepsy were created by pentylenetetrazol kindling, and were subdivided into 3-, 7-, and 14-day kindling subgroups. MAIN OUTCOME MEASURES： Gamma-aminobutyric acid transporter 1 and glial fibrillary acidic protein expression, as well as the number of positive cells in the hippocampus and cortex of temporal lobe of rats, were determined by immunohistochemistry and Western blot analyses. RESULTS： Compared with the control group, the number of gamma-aminobutyric acid transporter 1 and glial fibrillary acidic protein -positive cells in the hippocampus and cortex of rats with pentylenetetrazol-induced epilepsy significantly increased, gamma-aminobutyric acid transporter 1 and glial fibrillary acidic protein expression increased after 3 days of kindling, reached a peak on day 7, and remained at elevated levels at day 14 （P〈 0.05）. CONCLUSION： Astrocytic activation and gamma-aminobutyric acid transporter 1 overexpression may contribute to pentylenetetrazol-induced epilepsy.     

托吡酯对戊四氮致癫癎大鼠海马AQP4表达水平的影响

目的探讨托吡酯对戊四氮致癫癎大鼠海马AQP4表达水平的影响。方法将30只Wistar大鼠随机分为戊四氮致癫癎组、托吡酯干预组和正常对照组，每组各10只；癫癎模型点燃后在不同时相点灌注取材，通过HE染色观察大鼠海马神经元的变化，并应用免疫组化法检测大鼠海马AQP4表达水平。结果HE染色显示托吡酯干预组神经元变性和坏死较戊四氮致癫癎组明显减轻；免疫组化显示戊四氮致癫癎组在致癫癎后12hAQP4的表达显著增强，致癫癎后24h达高峰，托吡酯干预组在致癫癎后12h～36h各时相点AQP4表达水平均分别低于戊四氮致癫癎组相应时间点（P〈0．05）。结论托吡酯通过下调大鼠海马AQP4的表达可能参与了对大鼠海马神经元的保护过程。     

Chelatable zinc modulates excitability and seizure duration in the amygdala rapid kindling model

Zinc is present in high concentration in many structures of the limbic circuitry, however the role of zinc as a neuromodulator in such synapses is still uncertain. In this work, we verified the effects of zinc chelation in an animal model of epileptogenesis induced by amygdala rapid kindling.

The basolateral amygdala was electrically stimulated ten times per day for 2 days. A single stimulus was applied on the third day. Stimulated animals received injections of PBS or the zinc chelator diethildythiocarbamate acid (DEDTC) before each stimulus series. Animals were monitored with video-EEG and were perfused 3 h after the last stimulus for subsequent neo-Timm and Fluoro-Jade B analysis.

Zinc chelation decreased the duration of both behavioral seizures and electrical after-discharges, and also decreased the EEG spikes frequency, without changing the progression of behavioral seizure severity. These results indicate that the zinc ion may have a facilitatory role during kindling progression.     

Pentylenetetrazole kindling affects sleep in rats

PURPOSE: The aim of the study was to define sleep disturbances in pentylenetetrazole (PTZ)-kindled rats and to explore the effects of the nootropic drug piracetam (Pir; 100 mg/kg) and the noncompetitive N-methyl-D-aspartate (NMDA)-antagonist MK-801 (0.3 mg/kg), which normalized learning performance in PTZ-kindled rats, on altered sleep parameters. METHODS: This is the first report showing a significant reduction in paradoxical sleep (PS) as a consequence of PTZ kindling. A correlation analysis revealed a significant correlation between seizure severity and PS deficit. RESULTS: Pir did not interfere with seizure severity, and the substance did not ameliorate the PS deficit. However, the substance disconnected the correlation between seizure severity and PS deficit. MK-801, which reduced the severity of kindled seizures, counteracted the PS deficit efficaciously. CONCLUSIONS: The results suggest that seizure severity and alterations in sleep architecture are two factors in the comprehensive network underlying learning impairments associated with epilepsy. Considering the results obtained in the experiments with Pir, reduction of seizure severity does not guarantee the reduction of impairments in the domain of learning.     

癫(癎)幼鼠海马和颞叶皮质区缝隙连接蛋白43和突触体素表达的变化

目的观察神经元缝隙连接蛋白43(Cx43)和突触体素(synaptophysin P38)在戊四氮(PTZ)点燃癫癎幼鼠海马及颞叶皮质区中的表达,探讨两者与癫癎的关系及其在癫形成中的作用。方法将50只21日龄Wistar大鼠分为对照组和实验组。实验组采用PTZ点燃癫癎幼鼠,按点燃进程分为Ⅰ级、Ⅱ级、Ⅲ级、Ⅳ级及Ⅴ级发作组。采用免疫组化和图像分析技术,观察海马及颞叶皮质区Cx43和P38表达的变化。结果应用PTZ点燃后,实验各组幼鼠海马及颞叶皮质区Cx43和P38的表达明显高于对照组(P<0.01),且随发作级别的增高,幼鼠海马及颞叶皮质各区Cx43和P38的表达均增加。但各组间海马区和颞叶皮质区Cx43和P38的表达情况的比较差异无统计学意义(P>0.05)。结论Cx43和P38的表达水平与癫癎的发生发展有密切关系,为研究小儿癫癎的病因及发病机制提供依据。     

Seizure localization using EEG analytical signals

ObjectiveLocalization of epileptic seizures, usually characterized by abnormal hypersynchronous wave patterns from the cortex, remains elusive. We present a novel, robust method for automatic localization of seizures on the scalp from clinical electroencephalogram (EEG) data.MethodsSeizure patient EEG data was decomposed via the Hilbert Transform and processed through the following methodology: sorting the analytic amplitude (AA) in the time instance, locating the maximum amplitude within the vector of channels, cross-correlating amplitude values in the time index with the channel vector. The channel with highest AA value in time was located.ResultsOur approach provides an automated way to isolate the epi-genesis of seizure events with 93.3% precision and 100% sensitivity. The method differentiates seizure-related neural activity from other common EEG noise artifacts (e.g., blinks, myogenic noise).ConclusionsWe evaluated performance characteristics of our source location methodology utilizing both phase and energy of EEG signals from patients who exhibited seizure events. Feasibility of the new algorithm is demonstrated and confirmed.SignificanceThe proposed method contributes to high-performance scalp localization for seizure events that is more straightforward and less computationally intensive than other methods (e.g., inverse source modeling). Ultimately, it may aid clinicians in providing improved patient diagnosis.     

Dose-Finding Study with Nimodipine: A Selective Central Nervous System Calcium Channel Blocker on Aminophylline Induced Seizure Models in Rats

Nimodipine, a dihydropyridine derivative central nervous system (CNS) selective calcium channel blocker was studied at four different dosage schedules in five different models of seizures in rats. At a dose of 5 mg/kg, i.p. with pretreatment time of 15 min, nimodipine significantly antagonized aminophylline (175 and 200 mg/kg, i.p.), electroshock (150 mA for 0.2 s), pentylenetetrazole (60 and 75 mg/kg, i.p.), aminophylline (100 mg/kg i.p.) + electroshock (66mA for 0.2 s), and aminophylline (100 mg/kg, i.p.) + pentylenetetrazole (40 mg/kg, i.p.) induced seizures in rats. No hemodynamic alteration was observed with this dose of nimodipine. However, 2 mg/kg, i.p. (pretreatment time of 15 min and 30 min) and 5 mg/kg, i.p. (pretreatment time of 30 min) doses of nimodipine failed to demonstrate any significant anticonvulsant effect. The study highlighted the critical role of calcium ion flux into the neurons for the genesis of seizure activity to aminophylline, electroshock, and pentylenetetrazole in rats. Furthermore, the critical dose requirement for nimodipine could be explained on the basis of its short half-life and shorter duration of protection against seizures. Therefore, nimodipine may be tried clinically as an anticonvulsant in patients who are on aminophylline because of bronchial asthma or chronic obstructive pulmonary disease, when such patients have concomitant epilepsy or other seizure prone neurological deficits or are scheduled to undergo electroshock therapy.     

戊四氮对大鼠空间学习能力及情感行为的影响

目的 戊四氮(Pentylenetetrazole,PTZ)作为一种化学致癫剂往往用来在大鼠癫痫模型中检测某些潜在抗惊厥剂的抗癫效能,但目前关于戊四氮所模拟的癫痫发作后症状并未彻底研究.本研究旨在评估PTZ点燃大鼠的认知及情感功能损害的程度.方法 24只大鼠随机分为PTZ组(n=16)和对照组(n=8),PTZ组大鼠给予35mg·kg-1·48h-1,连续28天,对照组给予相应的生理盐水.停药一周后将造模成功大鼠进行学习能力和情感反应性的评估.结果 PTZ组大鼠在水迷宫测定中,寻找平台的潜伏期时间与对照组相比,没有显著差异,而对平台空间位置的记忆能力较对照组差(P＜0.01).在强迫游泳试验、系统性抓握试验(systematic handling test)及旷场探查试验中,PTZ组大鼠均出现异常的情绪反应,与对照组有显著性差异(P＜0.01).结论 用PTZ点燃模型研究癫痫大鼠学习记忆能力及情感行为发现,癫痫大鼠在水迷宫中学习记忆能力下降,并可引发或加重实验动物活动习性改变、警觉水平增高、惊恐行为、环境适应能力下降.因而,PTZ点燃大鼠能够为我们提供一个很好的模拟人类癫痫发作后功能损害的动物模型,为今后寻找治疗癫痫患者认知、情感损害的合适疗法提供了平台.     

Analysis of chronic seizure onsets after intrahippocampal kainic acid injection in freely moving rats

PURPOSE: The goal of this study was to analyze the transition period between interictal and ictal activity in freely moving rats with recurrent spontaneous seizures after unilateral intrahippocampal kainic acid (KA) injection. METHODS: Pairs of tungsten electrodes (50 microm O/D) were implanted bilaterally under anesthesia at symmetrical points in the dentate gyrus (DG) and CA1 regions of anterior and posterior hippocampi and entorhinal cortex of adult Wistar rats. Stimulating electrodes were placed in the right angular bundle and KA was injected into the right posterior CA3 area of hippocampus after 1 week of baseline EEG recording. Beginning 24 h after injection, electrographic activity was recorded with video monitoring for seizures every day for 8 h/day for 60 days. RESULTS: Seventy percent of seizures started locally in the DG ipsilateral to injection, with an increase in frequency of interictal EEG spikes (hypersynchronous type, HYP), and 26% of seizures started with a decrease of EEG amplitude with parallel increase in frequency (low-voltage fast type, LVF). During HYP seizures, a significant increase was observed in amplitude of beta-gamma range frequencies, ripple frequency, and fast ripple (FR) frequency, whereas during LVF seizure, an increase was noted only in the beta-gamma range. In all cases but one, an EEG wave preceded ripple and FR oscillations. Before seizure onset, the amplitude of DG-evoked responses to single pulses decreased, whereas the amplitude of the response to the second pulse delivered at 30-ms interval increased. CONCLUSIONS: If ripple and FR oscillations indicate the seizure-generating neuronal substrate, these areas must be small and widespread, so that the probability of recording from them directly is very low. The decreased response to electrical stimulation before seizures could indicate a protective inhibitory mechanism that contains or prevents seizure occurrence. The presence of decreased paired-pulse suppression could indicate a network predisposition to follow an external input with a certain frequency.