大鼠马桑内酯点燃癫痫模型P-糖蛋白和多药耐药相关蛋白1的表达

耐药性癫痫约占癫痫患者的30％，耐药癫痫动物模型是研究其耐药机制和探讨治疗方法的重要工具。马桑内酯（coriaria lactone，CL）是从植物马桑中提取的一种致痫物质，对动物反复肌注阈下剂量的CL可以建立化学点燃模型，并具有一定的耐药性。P-糖蛋白（P-glycorprotein，P-gp）和多药耐药相关蛋白1（muhidrug resistance-associated protein 1，MRP1）是近年在耐药性癫疴患者脑组织中发现的两种与耐药性产生相关的膜蛋白。     

杏仁核点燃癫痫鼠GAD67mRNA的表达

目的 探讨大鼠杏仁核点燃癫痫后脑组织谷氨酸脱羧酶（GAD）mRNA的表达及其在癫痫发作后表达变化的意义。方法 通过建立与人类癫痫发生,形成具有高度相似性的杏仁核点燃大鼠癫痫模型。采用原位杂交技术检测癫痫鼠颞叶及海马组织不同点燃时程GAD67mRNA表达。结果 点燃后1d,GAD67mRNA表达增多并且表达信号增强,至7d时达高峰,以后表达逐渐下降,但在点燃后49d,表达仍高于正常,与对照组及手术对照组相比有统计学差异。结论 在慢性癫痫发作中,GABA能神经元的活性增强,考虑是由于癫痫过程中兴奋性增强,引起GABA能神经元抑制功能代偿性增加的结果,即癫痫发作后GABA能神经元介入的抑制功能代偿性增加的,这可能是机体内源性抗癫痫机制增强的一种反应。     

杏仁核点燃癫痫大鼠P-糖蛋白及苔藓纤维出芽变化的研究

目的 观察杏仁核点燃癫痫大鼠海马区P-糖蛋白(P-gp)表达及苔藓纤维出芽(MFS)的动态变化. 方法 90只大鼠采用随机数字表法分为假手术对照组(10只)、癫痫组(40只)和治疗组(40只),假手术对照组只安装电极,不予刺激;癫痫组和治疗组制作杏仁核点燃模型,治疗组加用左乙拉西坦灌胃治疗[100 mg/(kg·d),2次/d)].采用Timm银染组织化学方法观察海马区MFS,免疫组化法检测P-gp的表达. 结果 (1)成功制造癫痫模型后,在海马CA3区透明层出现异常MFS,其中S1亚组大鼠MFS评分最低,与假手术对照组比较差异无统计学意义(P＞0.05);S2亚组大鼠评分开始增高,S4亚组大鼠明显增高,S8亚组大鼠达到高峰,与假手术对照组比较差异均有统计学意义(P＜0.05).而治疗组大鼠MFS评分各时间点与假手术对照组比较差异均无统计学意义(P＞0.05).(2)癫痫发作后癫痫组大鼠P-gp表达量呈现出逐渐降低的趋势,S1、S2、S4亚组与假手术对照组差异有统计学意义(P＜0.05);S8亚组接近正常水平,与假手术对照组比较差异无统计学意义(P＞0.05).治疗组大鼠除Y1亚组外,余各亚组P-gp表达量与假手术对照组比较差异均无统计学意义(P＞0.0S). 结论 MFS是慢性癫痫形成的重要机制,P-gp是癫痫发生的产物,是癫痫药物耐药的主要原因.     

有氧运动对鼠杏仁核点燃进程的影响

目的：分析急性和慢性有氧运动对鼠杏仁核电刺激点燃进程的影响。方法：第1组（急性组，n=10)有氧运动1次（游泳2h),运动后1min给予电刺激点燃；第2组（慢性组，n=10)接受有氧运动训练（每天游泳2h,共45d),然后与第1组同样处理；第3组（n=10)为对照组。各组均给予电刺激点燃，直到出现V级发作。结果：慢性组民另两组相比，达到V级发作所需电刺激的次数增多，具有统计学意义。与对照组相比，急性组和慢性组达到I级发作所需时间更长，并且在I组的痫性行为后放电时程短。结论：慢性运动可阻碍鼠的杏仁核点燃进程。     

快速点燃海马杏仁核建立癫痫鼠模型

目的：快速建立实验性癫痫动物模型。方法 １７只大鼠右侧海马和１１只鼠右侧杏仁核均埋植电极,用ＩＳ－２型智能刺激器,以２００－６００μＡ电脉冲刺激点燃海马杏仁核。结果 电刺激可诱发痫性发作和后放电,痫性行为分为五级,后放电呈高幅棘波。在过程中,可记录到两种脑电活动：痫性脑电活动和自发性痫性脑电活动。随着电刺激次数的增多,发现Ⅱ、Ⅲ级痫性行为伴随较短的后放电时程,Ⅳ级上以痫性行为伴随较长的后放电时程。     

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.     

P-糖蛋白在脑星形细胞瘤中的表达及意义

目的探讨脑星形瘤细胞P-糖蛋白(P-gp)的表达及临床价值。方法采用免疫组织化学法,对36例脑星形细胞瘤和3例来自颅脑损伤患者的脑组织及3例胎脑组织(作为对照)中P-gp的表达进行检测。对其中24例脑星形细胞瘤术后接受化疗患者的术后生存时间与P-gp表达的关系进行分析。结果P-gp在对照组6例脑组织中未见表达,而在36例星形细胞瘤中28例表达阳性,阳性表达率为77.8%,明显高于对照组(P<0.01)。在P-gp表达阳性的28例脑星形细胞瘤中,肿瘤细胞阳性表达9例,肿瘤间质血管内皮细胞阳性表达11例,二种细胞同时阳性表达8例。24例术后接受了化疗的患者中,6例P-gp表达阴性,18例表达阳性。在这24例病人中,P-gp表达阴性的病人术后5年生存率明显高于P-gp表达阳性者(P<0.05)。结论脑星形细胞瘤中P-gp不仅在肿瘤细胞表达,而且也在肿瘤间质血管内皮细胞表达,其对化疗药物的耐受性,存在肿瘤细胞和血脑屏障双重耐受机制,可能是脑星形细胞瘤产生多药耐受性的机理之一。P-gp的表达水平可能是影响病人术后化疗效果及术后生存时间的主要因素之一。     

microRNA-146a对癫(癎)大鼠脑内P-糖蛋白表达的影响

目的 观察microRNA-146a(miR-146a)对癫(癎)大鼠脑内P-糖蛋白(P-glycoprotein,P-gp)表达的影响.方法 健康雄性SD大鼠随机分为3组:miR-146a给药(miR-146a)组(n=8),经立体定向侧脑室注射给药;正常对照组(n=8)和癫(癎)组(n=8)给予相同体积的0.9％氯...     

大鼠杏仁核快速点燃癫痫模型

建立一种新型、实用的快速点燃癫痫动物模型。方法用频率１６Ｈｚ、波宽１．０ｍｓ、串长１０秒、串隔７分钟、强度０．４ｍＡ的恒流脉冲电流刺激３２只６～８周龄雄性Ｗｉｓｔａｒ大鼠的杏仁核。结果动物在０．５～４．０小时内就被点燃。模型稳定性好，致癫痫效应相对持久保留且向对侧杏仁核转移。其癫痫性行为规范，可控性和重复性好，易于判别与定量研究。动物对刺激反应性好，不易死亡。结论该模型满足了作为一种较理想的癫痫动物模型应具有的绝大多数先决条件。     

核因子-κB对癫痫大鼠脑 P-糖蛋白表达的调控作用

目的 探讨核因子-κB(NF-κB)对癫痫大鼠脑P-糖蛋白(P-gP)表达的影响.方法 将雄性SD大鼠随机分为假手术组(n=9)、癫痫组(EP组,n=14)、NF-κB活性抑制剂吡咯烷二硫代氨基甲酸盐(PDTC)干预组(PDTC组,n=14).采用大鼠海马注射海人酸方法制作癫痫模型,PDTC组于癫痫造模前30 min给予腹腔注射PDTC(按体质量150 mg/kg).于造模后24 h处死各组大鼠,采用免疫组织化学方法检测并比较各组大鼠海马CA3区、齿状回、嗅周皮层、杏仁核复合体区P-gp和NF-κB亚基p65(NF-κBp65)表达情况.结果 与假手术组相比,EP组海马CA3区、齿状回、杏仁核复合体区P-gP和NF-κBp65表达显著增强(PO.05).结论 抑制NF-κB活化可以降低癫痫相关脑区P-gp过表达,癫痫发作所致脑内P-gp表达上调可能与NF-κB活化有关.     

Kindling of the Visual Cortex in Cats: Comparison with Amygdaloid Kindling

Abstract: Kindling of the primary visual cortex (VC) was compared with that of the amygdala in cats. VC kindling was basically similar to kindling of the amygdala in that daily electrical stimulation can lead to the development of a generalized convulsion in most subjects, a growth of afterdischarges in their configuration and duration, and a reduction of the afterdischarge threshold. The kindling response of the VC differed from that of the amygdala in a number of respects, i.e., a high afterdischarge threshold, a different pattern of behavioral seizure development, an abrupt growth of electroclinical seizures coincident with the onset of a generalized convulsion, an intersubject variability in seizure susceptibility, and a marked seizure instability. In VC kindling the afterdischarge propagation into the amygdala was not observed until the generalized convulsion developed, and the early involvement of afterdischarge was seen in the pulvinar, lateral geniculate body, and superior colliculus. These data suggest that a neural mechanism different from amygdaloid kindling may participate in VC kindling, and that the sub-cortical structures of the visual system are involved in the preferential pathway for a seizure generalization from the VC.     

Amygdaloid Kindling in Papio Cynocephalus and Subsequent Recurrent Spontaneous Seizures*

Abstract: Three baboons, Papio cynocephalus, (two photosensitive and one nonphotosensitive) were subjected to amygdaloid kindling. Electroclinical profile of seizure development-developed seizure compares very favourably to that described in photosensitive baboons, Papio papio, with rapid seizure progression and ultimate emergence of Stage 5 bisymmetrical and bisynchronous generalized convulsive state. In addition, one baboon developed spontaneous recurrent seizures which were identical to the kindled Stage 5 seizure. It is concluded that the state of exceptional seizure susceptibility observed in Papio papio is shared by Papio cynocephalus, although photosensitivity and kindled generalized convulsion appear to be independent variables.     

Visual Cortical Kindling in Rabbit—Consideration of Difference between Species

Abstract: Visual cortical kindling was studied in chronically prepared rabbits with regard to the electrographic progress of epileptiform discharge trains following the daily stimulation and corresponding ictal behaviors. The spread of epileptiform discharges from the stimulated visual cortex to the parietal and frontal cortices of the stimulated side was observed early with the development of independent discharges In these parietal and frontal regions, accompanied by ictal motor symptoms of the contralateral side. In view of the past studies on rats, cats and monkeys, it was considered that such a spread in the neocortex and corresponding ictal behaviors might be specific to the rabbit.     

Alterations of Amygdaloid Kindling Phenomenon Following Repeated Electroconvulsive Shocks in Rats

Abstract: In this study we investigated the effect of the electroconvulsive shock (ECS) soon after each amygdaloid stimulation (KS) upon the development of a kindling phenomenon. Thirty male Wistar albino rats were used in this study. Once daily stimulation of 200 μA, 1 msec, 60 Hz, 2 sec train by the right amygdaloid stimulation electrodes and the recording of the EEG were done. Rats of the Kindling + ECS group received the ECS through the clipped ears for five minutes after the KS. Behavioral manifestations, the duration of afterdischarge and the numbers of spikes were counted for five minutes at the time of every stimulation. The numbers of times the KS required to develop each stage were stage 1:4.8, stage 2:8, stage 3:8.6, stage 4:9.6, stage 5:12.6, respectively, on the kindling group. On the ECS-treated group, those were stage 1:8, stage 2:17, stage 3:18, stage 4: more than 20. The ECS soon after the amygdaloid stimulation retarded the process of kindling significantly. This result is consistent with the hypothesis that the electroconvulsive shocks disturb the information of the synaptic pathway before the consolidation of a central neuroplastic change underlying kindling.     

Low Doses of the Glycine/NMDA Receptor Antagonist R-(+)-HA-966 but not d-Cycloserine Induce Paroxysmal Activity in Limbic Brain Regions of Kindled Rats

(+)-HA-966 [ R -(+)-3-amino-1-hydroxypyrrolid-2-one], a functional antagonist at the glycine modulatory site on the W-methyl-D-aspartate (NMDA) receptor/ion channel complex, was evaluated in amygdala-kindled rats, a model of epilepsy recently shown to exhibit enhanced susceptibility to the adverse effects of competitive and non-competitive NMDA receptor antagonists. Since (+)-HA-966 displays weak partial agonistic effects at the glycine site (−10% efficacy of glycine), D-cycloserine, a glycine ligand with much higher intrinsic activity, was evaluated in kindled rats for comparison. Following drug administration, electrographic activity was recorded from the basolateral amygdala (i.e. the focal site) as well as the ipsilateral piriform cortex, ventral hippocampus and nucleus accumbens. In addition to the evaluation of original recordings, power spectrum analysis was used to delineate drug effects. (+)-HA-966 (20–40 mg/kg i.p.) induced marked alterations in electrographic recordings, including increases in amplitude and isolated spiking, i.e. signs of paroxysmal activity. The severity or duration of fully kindled seizures was not changed by (+)-HA-966, but the drug dramatically increased the duration of immobilization and limbic seizure activity following a kindled motor seizure. In contrast to (+)-HA-966, D-cycloserine did not induce any electrographic changes, even when administered in much higher doses than (+)-HA-966. The changes in electrographic recordings seen after administration of (+)-HA-966 in kindled rats were almost absent in non-kindled rats, indicating that kindling had increased the sensitivity to the paroxysmal effects of the glycine/NMDA receptor ligand. The data indicate that functional glycine/NMDA antagonists with low intrinsic efficacy may bear the risk of proconvulsant activity.     

Comparison of Kindling at Short Interstimulus Intervals in Acutely and Chronically Prepared Rabbits

Abstract: For the purpose of contributing methodologically to experimental research on epilepsy, we investigated whether a difference exists in kindling development between acute and chronic preparations using identical species of animals, kindled brain tissues, stimulus intervals, and intensities. Seizure-threshold stimulations repeatedly applied at 5-min intervals to the unilateral visual cortex in rabbits completed the generalization of epileptiform discharge trains after the llth-24th trials in the acute preparations concomitantly with an increase in the afterdischarge duration and the development of independent discharges, whereas they induced no kindling phenomena even with 50 trials in the chronic preparations. These results indicate that there is an extreme difference in kindling susceptibility between acute and chronic preparations, resulting, presumably, from multifactorial dissimilarities in these experimental conditions.     

The Effect of Generalized Absence Seizures on the Progression of Kindling in the Rat

Summary:  The involvement of the thalamus in limbic epileptogenesis has recently drawn attention to the connectivity between the nuclei of the thalamus and limbic structures. Thalamo-limbic circuits are thought to regulate limbic seizure activity whereas thalamocortical circuits are involved in the expression and generation of spike-and-wave discharges (SWDs) in the absence epilepsy models. Genetic Absence Epilepsy Rats From Strasbourg (GAERS) and WAG/Rij (Wistar Albino Glaxo from Rijswijk) are well-defined genetic animal models of absence epilepsy. We aimed to examine the duration of behavioral changes in the kindling process and the relation of SWD activity to the kindling progress in the GAERS and WAG/Rij animals. Electrodes were stereotaxically implanted into the basolateral amygdala and the cortex of rats for stimulation and recording. The animals were stimulated at the threshold for producing afterdischarges. EEG was recorded to analyze SWDs and afterdischarge durations. The seizure severity was evaluated using Racine's 5-stage scale. None of the GAERS animals reached stage 3, 4, or 5 after application of 30 stimulations. The WAG/Rij animals showed different rate of kindling, therefore they were further categorized into the kindling-resistant, slow-kindled, and rapid-kindled groups. The kindling-resistant animals demonstrated a significantly longer duration of SWDs on the first day of the experiment before kindling stimulation and shorter duration of afterdischarge than did the kindled WAG/Rij animals. Behavioral durations at stage 2 were longer in kindled Wistar and WAG/Rij animals compared to kindling-resistant WAG/Rij and GAERS. These results suggest that mechanisms involved in the generation of SWDs act as a counterbalance to the excitability induced by kindling.     

Acute Effect of TRH, Fhmarizine, Lithium and Zotepine on Amygdaloid Kindled Seizures Induced with Low-Frequency Stimulation

Abstract: We assessed the acute effects of various drugs on amygdaloid kindled seizures induced with low-frequency stimulations. We used the number of stimulating pulses required for the induction of epileptic afterdischarge (pulse-number threshold; PNT) as an indicator of the seizure generating threshold and the duration of induced seizures (AD duration; ADD) as an indicator of the seizures. TRH increased the PNT without affecting the ADD at a high dose (1.2 mg/kg). Flunarizine decreased the PNT and ADD simultaneously at a high dose (50 mg/kg). Lithium increased the PNT without affecting the ADD at two doses (100 mg/kg, 200 mg/kg). Zotepine decreased the PNT without affecting the ADD at two doses (8 mg/kg, 16 mg/kg). We propose that the technique of low-frequency kindling is a useful experimental model in assessing the effects of antipsychotic or antiepileptic drugs on the excitability of the limbic regions.     

The effect of oral administration of monosodium glutamate on epileptogenesis in infant rats

Aim: Glutamate is an excitatory neurotransmitter that is widely distributed throughout the brain. An increase in glutamate concentration or sensitivity of glutamate receptors triggers neurodegenerative diseases, epilepsy in particular. Monosodium glutamate is a substance added to foods to enhance flavour. We investigated the effect of monosodium glutamate on epileptogenesis, as well asheight and weight, in rats that were just weaned. Methods: Twenty‐four male and female 21‐day‐old Wistar Albino rats were divided into two groups: one with monosodium glutamate added to the drinking water, and a control in which NaCl was added to the drinking water. The electrical stimulation threshold values were determined in animals to which the hippocampal kindling process was applied, and the stimulations at these threshold values were invariably applied to the animals until they were kindled. Results: The electrical stimulation threshold values of the monosodium glutamate group did not statistically change, whereas the number of required stimulations for kindled rats was significantly lower compared with the control group. Conclusion: These results reveal that long‐term oral administration of glutamate salts causes an increase in excitability in the central nervous system during ontogenetic development.     

Kindling phenomenon of hyperthermic seizures in the epilepsy-prone versus the epilepsy-resistant rat

A kindling-like effect was produced by exposing 30-day-old rats to repeated hyperthermia-induced seizures. Naive audiogenic seizure (AGS)-susceptible rats (P77PMC) were easier to be kindled than AGS-resistant rats (Wistar). This hyperthermic kindling model may be used to study the outcome and mechanisms of human febrile seizures. The mechanisms underlying hyperthermic kindling remain to be investigated.