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。     

雌激素对癫痫大鼠大脑皮层,海马FOS蛋白表达的影响

目的了解雌激素对马桑内酯(CL)致痫大鼠中枢神经系统FOS蛋白(FOS)表达的影响。方法应用流式细胞免疫荧光技术对CL致痫及给予雌激素后再致痫大鼠大脑皮层、海马细胞FOS表达进行定量检测。结果CL致痫组大鼠大脑皮层、海马FOS表达的荧光指数(FI)和阳性细胞数较正常对照组明显增高(P＜0.01);给予雌二醇(E2)后再致痫组皮层、海马FOS表达较单纯CL致痫组增加(P＜0.05,P＜0.01)。结论由于FOS可作为神经元兴奋的标志,雌激素可以提高皮层、海马神经细胞的兴奋性,提示雌激素有致痫性。     

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。     

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。     

孕激素对癫痫大鼠大脑皮层,海马FOS蛋白表达的影响

本实验采用流式细胞免疫荧光技术对马桑内酯（ＣＬ）致痫及给予孕激素后再致痫大鼠大脑皮层、海马细胞ＦＯＳ表达进行定量检测。结果显示：ＣＬ致痫组大鼠皮层、海马ＦＯＳ表达的荧光指数（ＦＩ）和阳性细胞数较正常对照组明显增高（Ｐ＜０．０１）；给予孕酮（Ｐ）后再致痫组皮层、海马ＦＯＳ表达较单纯ＣＬ致痫组减少（Ｐ＜０．０１，Ｐ＜０．０５）。     

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。     

癫痫伴发抑郁大鼠杏仁核突触相关蛋白的表达

目的 观察癫痫伴发抑郁(EAD)大鼠杏仁核神经生长相关蛋白(GAP-43)、突触素(SYN)、突触后致密蛋白95(PSD95)的表达情况,探讨这3种突触相关蛋白在EAD发病中的作用.方法 将健康成年SD大鼠随机分为共病组、癫痫组、抑郁组和正常组.采用氯化锂-匹罗卡品法建立癫痫模型,于造模后第14天对癫痫模型进行抑郁筛选...     

难治性癫痫大鼠脑内多药耐药相关蛋白1表达的研究

目的 研究杏仁核电刺激点燃的难治性癫痫大鼠脑内多药耐药相关蛋白1（multidrug resistant-associated protein 1 MRP1）表达的情况.方法 建立杏仁核电刺激点燃的难治性癫痫大鼠模型,用免疫组织化学及免疫蛋白印记（western blot）的方法,分析比较MRP1蛋白在癫痫模型组与正常对照组的表达.结果 药物难治性癫痫大鼠组脑内多药耐药相关蛋白的表达显著高于正常对照组（P〈0.01）.在癫痫大鼠脑内广泛分布的MRP1免疫阳性细胞主要为毛细血管内皮细胞和星形胶质细胞.结论 癫痫大鼠脑内高表达的MRP1参与了难治性癫痫的耐药机制.     

尼莫地平对杏仁核点燃鼠模型脑内谷氨酸及P-糖蛋白表达的影响

目的：观察尼莫地平对杏仁核癫痫点燃鼠模型脑内谷氨酸（Glu）及P-糖蛋白（P-gP）表达的影响。方法：选择健康雄性Wistar大鼠30只制作癫痫模型,造模成功后随机分为未点燃正常组、癫痫模型组和尼莫地平组。1周后分别取鼠脑组织,采用免疫组化检测大鼠脑内Glu和P-gp表达,比较各组表达的变化。结果：①癫痫模型组中杏仁核、海马和颞叶P-gp阳性细胞计数（分别为14．05±10．95、10．05±8．23和7．64±5．89）较未点燃正常组（4．32±6．69、3．96±3．04和2．15±1．40）和尼莫地平组（6．88±9．18、4．48±6．50和2．68±1．37）明显增多（P〈0．05）;尼莫地乎组P-gp阳性细胞数与未点燃正常组比差异无统计学意义。②癫痫模型组中杏仁核、海马和颞叶Glu的平均透光率（％）（分别为18．51±3．19、19．21±2．56和20．50±2．84）与未点燃正常组（23．03±7．29、24．88±5．55和26．11±7．17）Lh有明显降低（P〈0．05）,而尼莫地平组（19．60±4．84、20．71±6．04和21．44±5．52）与癫痫模型组比差异无统计学意义（P〉0．05）。③Glu和P．gp的表达均以杏仁核最强,其次为海马和颞叶,特别是在癫痫模型组中。结论：①尼莫地平在杏仁核电刺激点燃模型中可明显抑制杏仁核、海马、颞叶的P-gp表达,但不能抑制Glu的表达;②Glu和P-gp在杏仁核、海马和颞叶中的表达程度不同,以杏仁核表达最强。     

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。     

Claustral lesions delay amygdaloid kindling in the rat

PURPOSE: Lesions of the claustrum in cats and primates have been shown to disrupt the development and expression of amygdaloid-kindled seizures in cats and primates. Because the structure and connectivity of the claustrum can vary between species, we wanted to examine the effects of claustral lesions on kindling in rats. METHODS: One group of rats received bilateral radiofrequency lesions of both anterior and posterior regions of the claustrum before amygdaloid kindling. Another group of rats received bilateral anterior and posterior radiofrequency lesions of the claustrum after amygdaloid kindling. Some rats were tested for transfer of kindling to the contralateral amygdala after claustral lesions. RESULTS: Small lesions that destroyed 13% of the claustrum were capable of delaying, but not blocking, amygdaloid kindling. The delay in kindling was due to an increase in the stimulation trials required to kindle to stage 5 seizures. The lesions had no effect on established kindled seizures or on transfer to the contralateral amygdala. CONCLUSIONS: As in other species, the claustrum in the rat appears to play a role in kindling from the amygdala. Because of the restricted size of our claustral lesions, however, we were unable to conclusively assess the full extent of the claustrum's participation in limbic kindling.     

Ca/calmodulin-dependent protein phosphorylation is not altered by amygdaloid kindling

Kindling is a process in which episodic electrical stimulation permanently increases seizure susceptibility. One mechanism to account for a change in seizure susceptibility is some alteration in signal transduction, possibly at the level of second messenger systems. In this study, male Long-Evans rats were kindled in the amygdala, and Ca²⁺/calmodulin (Ca²⁺/CaM)-dependent protein phosphorylation was assessed at the site of the primary kindled focus using one- and two-dimensional gel electrophoresis. In vitro phosphorylation of membrane and cytosol fractions in the presence or absence of Ca²⁺/CaM did not differentiate kindled from nonkindled amygdaloid tissue. These results suggest that changes in Ca²⁺/CaM-dependent phosphorylation are not related to the mechanism(s) underlying the establishment of an amygdaloid kindled focus.     

Effect of transient hippocampal inhibition on amygdaloid kindled seizures and amygdaloid kindling rate

In this study the effect of transient inhibition of the CA1 region of the dorsal hippocampus by lidocaine on amygdala kindling rate and amygdaloid kindled seizures was investigated. In experiment 1, rats were divided into four groups. In group 1, animals were implanted only with a tripolar electrode into the amygdala but in groups 2-4, two guide cannulae were also implanted into the CA1 regions of the dorsal hippocampi. Animals were stimulated daily to be kindled. In groups 3 and 4, saline or 2% lidocaine (1 microl/2 min) was also injected respectively into the hippocampus, 5 min before each stimulation. Results obtained showed that amygdala kindling rate and the number of stimulations to receive from stage 4 to stage 5 seizure were significantly increased in group 4. In experiment 2, lidocaine (1% and 2%) was infused (1 microl/2 min) into the hippocampus of amygdala kindled rats bilaterally and animals were stimulated at 5, 15 and 30 min after drug injection. Twenty four h before lidocaine injection, saline was also infused (1 microl/2 min) into the hippocampus as control. Obtained results showed that afterdischarge duration was reduced 5 min after lidocaine (1% and 2%) injection. Stage 5 seizure duration was also decreased 5 and 15 min after 2% lidocaine. Thus, it may be suggested that in amygdala kindling, activation of the hippocampal CA1 region has a role in seizure acquisition and seizure severity so that inhibition of this region results in decreasing of seizure severity and retards amygdala kindling rate.     

Effects of chronic naloxone pretreatment on amygdaloid kindling in rats

Effects of chronic naloxone pretreatment (75 or 270, μg/h for 14 days) on the development of amygdaloid kindling in rats were evaluated. The acquisition of seizure activity was modified in the naloxone pretreated animals, depending on the nucleus stimulated: facilitation of stages IV and V occurred in 37%, variability of electrographic and behavioral responses to electrical stimulation during the kindling development in 33%, and facilitation of stages IV and V followed by long periods of seizure suppression in 29%. Enhancement of postictal seizure suppession during a recycling paradigm was observed in all the naloxone pretreated rats. It was concluded that the chronic administration of naloxone (known to induce opioid binding upregulation and supersensitivity), in association with the enduring changes in opioid mechanisms provoked by kindled seizures, were responsible for the facilitation and suppression of epileptic activity. These findings support bidirectional modulatory effects of opioid peptides on epileptic seizures as well as the view that epileptic seizures can induce enduring alterations in opioid mechanisms.     

Saving-effect of stimulating pulses at low-frequency amygdaloid kindling in cats

Cats were stimulated in the lateral amygdala with low-frequency square-wave pulses. All subjects were kindled until generalized convulsion occurred. During the kindling process, a prolongation of the interpulse interval and a reduction of the number of pulses required for the provocation of afterdischarges were observed. We refer to this phenomenon as the ‘saving-effect’ of stimulating pulses to provoke afterdischarges.     

Effects of neurotensin on neurons in the rat central amygdaloid nucleus in vitro

The effects of neurotensin (NT) on neurons in the central amygdaloid nucleus (ACe) were investigated in rat brain slice preparations by adding the peptide to the perfusing medium. Of 115 ACe neurons, 69 cells (60%) showed excitatory responses and 10 cells (9%) showed inhibitory responses to application of NT. The excitatory response to NT was observed in a dose-dependent manner and the threshold concentration was approximately 3 × 10⁻⁹ M. The excitatory effects of NT persisted under blockade of synaptic transmission. The NT fragment neurotensin 8–13 and the NT analogue neuromedin N showed effects similar to those of NT, whereas the NT fragment neurotensin 1–8 had no effect on ACe neurons. Of 43 neurons in the septal nucleus, 8 cells (19%) and 3 cells (7%) showed excitatory and inhibitory responses, respectively, to NT. The results suggest that NT exerts a potent excitatory effect on ACe neurons through a direct action on specific receptors, in which NT may play a role in amygdala-relevant functions.     

Effects of vasopressin and involvement of receptor subtypes in the rat central amygdaloid nucleus in vitro

Effects of arginine-vasopressin (AVP) on neurons in the central amygdaloid nucleus (ACe) were investigated with rat brain slice preparations using extracellular recording methods. Of 160 ACe neurons tested, 70 cells (44%) were excited and 9 cells (6%) were inhibited by bath application of AVP at 3×10⁻⁷ M. The excitatory effects of AVP were dose-dependent and the threshold concentration was approximately 10⁻¹⁰ to 10⁻⁹ M. The excitatory effects of AVP persisted under blockade of synaptic transmission by perfusing with Ca²⁺-free and high-Mg²⁺ medium, whereas the inhibitory effects were abolished by synaptic blockade. AVP-induced effects were mimicked by a V₁-receptor agonist and completely blocked by a selective V₁-antagonist. V₂-agonist produced no effects on ACe neurons and V₂-antagonist had no effect on AVP-induced excitation. These results showed that the excitatory effect of AVP on ACe neurons was produced by a direct action through the V₁-receptors, whereas the inhibitory response of ACe neurons to AVP seemed to be produced by an indirect action. The results of this study suggest that AVP is involved in the amygdala-relevant functions as a neurotransmitter or a neuromodulator.     

Common epileptic pathway in amygdaloid bicuculline and electrical kindling demonstrated by transferability

The transferability between amygdaloid bicuculline kindling and electrical kindling was studied in rats. Electrically kindled animals exhibited stage 5 generalized seizures on the first injection of bicuculline, in contrast to the 3–7 injections required in controls. Similarly, bicuculline-kindled animals reached stage 5 after significantly fewer electrical stimulations than controls; two-thirds of the bicuculline-kindled animals began in stage 1 but skipped stages 3 and 4 on their way to stage 5. These data indicate that a common generalization mechanism exists in both types of kindling, but the process of progression from local seizure to generalized seizure may be immature in bicuculline kindling.     

Changes in subcortical visual and auditory evoked potentials following amygdaloid kindling in cats

In this study we dealt with the changes in visual and auditory evoked potentials following kindling, to reveal the distant effects of epileptic activity. The experiments were performed using cats. Visual and auditory evoked potentials were obtained initially. Daily stimulation of 60 Hz (rectangular wave, 1 ms in duration, 500 microA in peak current, 2-s train) was given to the right amygdala, for kindling. After the completion of kindling, evoked responses were recorded again. In the auditory system the changes of responses in the cortex, medial geniculate nucleus, and cochlear nucleus were distinguished. The changes of potentials in the subcortex were larger than those at the cortical level. For visual evoked potentials there was a discrepancy between stimulation with light and electrical stimulation of the optic chiasm. There was no significant change in amplitude of visual evoked potentials by flash. In the case of optic chiasm stimulation, an enlargement of evoked responses was obtained. These results indicate modality-specific change of the auditory system and widespread subcortical change. These results might be caused by some vulnerability of the auditory system in the case of amygdaloid kindling, as a result of the epileptogenic process.