白藜芦醇调控癫痫持续状态大鼠海马内源性巯醇抗氧化剂(酶)的作用

目的 探讨白藜芦醇(Res)在氯化锂联合重复低剂量匹罗卡品诱导癫痫持续状态大鼠模型中的抗氧化作用及其机制.方法 54只SD大鼠随机分为 3 组:对照组、癫痫模型组和Res治疗组,采用氯化锂联合重复低剂量匹罗卡品腹腔注射制备癫痫持续状态大鼠模型,Res治疗组同时给予白藜芦醇预防性治疗.对大鼠按痫性分级标准进行行为学观测;...     

D-半乳糖调控SD大鼠大脑皮质巯醇抗氧化物(酶)致衰老的作用研究

构建D-半乳糖(D-gal)致衰老模型,探讨D-gal诱导衰老的分子机制,为临床治疗阿尔茨海默病(AD)提供理论依据。腹腔注射D-gal构建SD大鼠衰老模型,采用Morris水迷宫实验(MWM)进行行为学检测,采用化学比色法检测大脑皮质一氧化氮合酶(NOS)、一氧化氮(NO)、铜锌-过氧化物岐化酶(Cu,Zn-SOD)、总超氧化物歧化酶(T-SOD)、谷胱甘肽还原酶(GR)、谷胱甘肽s-转移酶(GSH-ST)、谷胱甘肽过氧化酶(GSH-PX)、谷胱甘肽(GSH)、丙二醛(MDA),总抗氧化能力(T-AOC)和过氧化氢(H2O2)的含量。结果显示:衰老模型组与正常对照组比较:逃避潜伏期明显延长(P<0.05),在第III象限逗留的时间明显减少(P<0.05),跨越平台次数明显减少(P<0.05);皮质MDA、H2O2和NO的含量增加(P<0.05),SOD、GSH、GSH-ST、GSH-Px和T-AOC的含量降低(P<0.05),而NOS的含量没有明显变化(P>0.05)。结果提示,D-gal能通过调控内源性巯基抗氧化物(酶)和NO的表达,减退学习记忆能力,而诱导SD大鼠神经系统的衰老。     

三七皂苷Rg1上调SD大鼠大脑皮质巯醇抗氧化物(酶)发挥抗衰老作用

目的探讨三七皂苷Rg1抗衰老的分子机制。方法90只SD大鼠随机分为假手术组、模型组和治疗组。采用侧脑室注射β淀粉样蛋白1-42(Aβ1-42)联合腹腔注射D-半乳糖(D-gal)构建SD大鼠衰老模型,并同时给予三七皂苷Rg1预防性治疗,采用Morris水迷宫实验(MWM)进行行为学检测,用化学比色法检测大脑皮质谷胱甘肽还原酶(GR)和谷胱甘肽过氧化物酶(GSH-Px)的含量。用免疫组织化学法和免疫印迹法检测大脑皮质中Caspase-3前体蛋白和Bcl-2的含量。结果衰老模型组与假手术组比较:逃避潜伏期明显延长(P0.05),在第Ⅲ象限逗留的时间明显减少(P0.05),跨越平台次数明显减少(P0.05),皮质GR和GSH-Px的含量降低(P0.05),Caspase-3前体蛋白阳性神经元数明显减少(P0.05),Caspase-3前体蛋白活化切割增加(P0.05);而三七皂苷Rg1治疗后:大鼠逃避潜伏期明显缩短(P0.05),在第Ⅲ象限逗留的时间明显增加(P0.05),跨越平台次数明显增加(P0.05),皮质GR和GSH-Px的含量升高(P0.05),Caspase-3前体蛋白阳性神经元数明显增加(P0.05),Caspase-3前体蛋白活化切割减少(P0.05)。而Bcl-2阳性神经元数及表达在3组之间没有显著差异(P0.05)。结论三七皂苷Rg1能通过上调衰老模型大鼠皮质内源性巯基抗氧化物(酶)GR和GSH-Px的含量,抑制凋亡相关蛋白Caspase-3前体蛋白的活化切割而改善学习记忆能力,对抗大鼠神经系统衰老。     

17-β雌二醇提高巯醇抗氧化物(酶)治疗脊髓损伤的作用

目的探讨17-β雌二醇治疗脊髓损伤的分子机制,为临床应用雌激素治疗脊髓损伤提供理论依据。方法成年雄性SD大鼠180只,采用改良的Allen法构建大鼠急性脊髓挫伤模型后经17-β雌二醇治疗,采用化学比色法测定脊髓组织中丙二醛(MDA)和内源性巯醇抗氧化物(酶):还原型谷胱甘肽(GSH)、超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)含量;免疫组织化学分析凋亡相关因子Caspase-3、Bcl-2和Bax蛋白的表达变化。结果17-β雌二醇治疗组与脊髓损伤组比较,BBB评分明显增加;在多个时间点MDA含量明显降低;巯醇抗氧化物(酶)GSH、SOD和GSH-Px含量显著增加;Caspase-3和Bax表达的阳性细胞数明显减少;Bcl-2表达的阳性细胞数明显增加(P0.05)。结论大剂量的17-β雌二醇治疗可能通过调控内源性巯醇抗氧化物(酶),提高肢体运动功能,抑制细胞凋亡,从而减轻脊髓损伤程度。     

17-β雌二醇提高巯醇抗氧化物（酶）治疗脊髓损伤的作用 

目的 探讨17-β雌二醇治疗脊髓损伤的分子机制,为临床应用雌激素治疗脊髓损伤提供理论依据。 方法 成年雄性SD大鼠180只,采用改良的Allen法构建大鼠急性脊髓挫伤模型后经17-β雌二醇治疗,采用化学比色法测定脊髓组织中丙二醛（MDA）和内源性巯醇抗氧化物（酶）：还原型谷胱甘肽（GSH）、超氧化物歧化酶（SOD）和谷胱甘肽过氧化物酶（GSH-Px）含量;免疫组织化学分析凋亡相关因子Caspase-3、Bcl2和Bax蛋白的表达变化。 结果 17-β雌二醇治疗组与脊髓损伤组比较,BBB评分明显增加;在多个时间点MDA含量明显降低;巯醇抗氧化物（酶）GSH、SOD和GSH-Px含量显著增加;Caspase-3和Bax表达的阳性细胞数明显减少;Bcl2表达的阳性细胞数明显增加（P<0.05）。 结论 大剂量的17-β雌二醇治疗可能通过调控内源性巯醇抗氧化物（酶）,提高肢体运动功能,抑制细胞凋亡,从而减轻脊髓损伤程度。     

匹罗卡品诱发癫痫持续状态大鼠模型的改良和鉴定

目的 对匹罗卡品诱发的癫痫持续状态大鼠模型进行改良和鉴定.方法 SD大鼠(6 ～ 8周,雌性)注射氯化锂、丁溴东莨菪碱、匹罗卡品诱发癫痫持续状态,分别在急性期和慢性自发癫痫形成期接受脑电监测和海马病理学检查.结果 行为学上急性期匹罗卡品组(PISE)出现Racine分级的IV级或以上发作,慢性自发癫痫形成期每周可见自发...     

P> 三七皂苷Rg1上调SD大鼠大脑皮质巯醇抗氧化物（酶）发挥抗衰老作用/P>

目的 探讨三七皂苷Rg1抗衰老的分子机制。 方法 90只SD大鼠随机分为假手术组、模型组和治疗组。采用侧脑室注射β淀粉样蛋白1-42（Aβ_1-42）联合腹腔注射D半乳糖（D-gal）构建SD大鼠衰老模型,并同时给予三七皂苷Rg1预防性治疗,采用Morris水迷宫实验（MWM）进行行为学检测,用化学比色法检测大脑皮质谷胱甘肽还原酶(GR)和谷胱甘肽过氧化物酶(GSH-Px)的含量。用免疫组织化学法和免疫印迹法检测大脑皮质中Caspase-3前体蛋白和Bcl-2的含量。 结果 衰老模型组与假手术组比较：逃避潜伏期明显延长(P<0.05),在第Ⅲ象限逗留的时间明显减少(P<0.05),跨越平台次数明显减少(P<0.05),皮质GR和GSH-Px的含量降低(P<0.05),Caspase-3前体蛋白阳性神经元数明显减少(P<0.05),Caspase-3前体蛋白活化切割增加(P<0.05);而三七皂苷Rg1治疗后：大鼠逃避潜伏期明显缩短(P<0.05),在第Ⅲ象限逗留的时间明显增加(P<0.05),跨越平台次数明显增加(P<0.05),皮质GR 和GSH-Px的含量升高(P<0.05),Caspase-3前体蛋白阳性神经元数明显增加(P<0.05),Caspase-3前体蛋白活化切割减少(P<0.05)。而Bcl-2阳性神经元数及表达在3组之间没有显著差异(P>0.05)。 结论 三七皂苷Rg1能通过上调衰老模型大鼠皮质内源性巯基抗氧化物（酶）GR 和GSH-Px的含量,抑制凋亡相关蛋白Caspase-3前体蛋白的活化切割而改善学习记忆能力,对抗大鼠神经系统衰老。     

天麻素调控癫痫大鼠大脑皮质凋亡因子的作用研究

目的:探讨天麻素对氯化锂-匹罗卡品诱导癫痫大鼠模型中大脑皮质神经元凋亡因子表达的作用及其机制,为临床应用天麻素治疗癫痫提供分子生物学依据。方法:80只雄性SD大鼠随机分为5组:即对照组、模型组、60 mg/kg天麻素预治疗组、120 mg/kg天麻素预治疗组和180 mg/kg天麻素预治疗组。采用氯化锂-匹罗卡品联合制备癫痫模型,治疗组给予不同剂量的天麻素预处理,模型组给以相同剂量的生理盐水。按Racine分级标准观察行为学变化,记录大发作潜伏期时间,于注射匹罗卡品后2 h给予安定终止;3 d后取材,免疫组织化学染色、免疫荧光染色和Western Blot检测凋亡相关蛋白表达变化。结果:天麻素治疗组较模型组,癫痫发作潜伏期延长,持续时间明显减少,程度减轻,死亡率显著降低,Bcl-2表达增加,Caspase-3显著降低。结论:天麻素可减少癫痫模型大鼠发作持续时间和程度,降低癫痫大鼠死亡率;天麻素通过增加癫痫大鼠大脑皮质Bcl-2和降低Caspase-3的表达而抑制凋亡,发挥脑保护作用。     

三七皂苷Rg1调控SD大鼠海马抗氧化物(酶)抗衰老的作用研究

目的:探讨三七皂苷Rg1(notoginsenoside,Rg1)抗衰老的分子机制。方法:将90只SD大鼠随机分为3组:假手术组、模型组、治疗组。采用侧脑室注射β淀粉样蛋白1-42(Aβ1-42)联合腹腔注射D-半乳糖(D-gal)构建SD大鼠衰老模型,并同时给予三七皂苷Rg1预防性治疗,采用Morris水迷宫实验(MWM)进行空间学习记忆能力检测;用化学比色法检测海马谷胱甘肽还原酶(GR)和总超氧化物歧化酶(T-SOD)的含量;用免疫组织化学法和免疫印迹法(Western Blot)检测海马中caspase-3前体蛋白和Bcl-2的含量。结果:衰老模型组与假手术组比较:逃避潜伏期明显延长(P0.05),在第Ⅲ象限逗留的时间明显减少(P0.05),跨越平台次数明显减少(P0.05);海马GR和T-SOD的含量降低(P0.05),caspase-3前体蛋白阳性神经元数明显减少(P0.05),caspase-3前体蛋白活化切割增加(P0.05);而三七皂苷Rg1处理后:大鼠逃避潜伏期明显缩短(P0.05),在第III象限逗留的时间明显增加(P0.05),跨越平台次数明显增加(P0.05),海马GR和T-SOD的含量升高(P0.05),caspase-3前体蛋白阳性神经元数明显增加(P0.05),caspase-3前体蛋白活化切割减少(P0.05)。而Bcl-2阳性神经元数及表达在三组之间差异无统计学意义(P0.05)。结论:三七皂苷Rg1能通过上调衰老模型大鼠海马抗氧化物(酶)GR和T-SOD的含量、抑制凋亡相关蛋白caspase-3前体蛋白的活化切割,而改善学习记忆能力,对抗大鼠神经系统衰老。     

氯化锂匹罗卡品诱导癫痫大鼠海马神经元GPER1表达的变化

目的:观察G蛋白偶联雌激素受体1(GPER1)在癫痫大鼠海马神经元中表达的变化。方法:成年雄性SD大鼠分成对照组(control)和癫痫组(epilepsy),利用腹腔注射氯化锂-匹罗卡品方法制备癫痫模型,分别在1、2、3、7、14 d和28 d,利用Morris水迷宫检测大鼠学习记忆能力,利用尼氏染色观察大鼠海马神经元形态变化;利用免疫组化和Western Blot技术观察GPER1在海马的表达。结果:水迷宫结果显示,与Control组相比,造模14 d的大鼠逃逸潜伏时间明显延长(P 0. 05),穿越目标象限区域的次数较Control组显著降低(P 0. 05)。尼氏染色结果显示:与Control组相比,造模1 d和2 d的大鼠CA1及CA3区锥体细胞层细胞及DG区颗粒细胞层细胞体积缩小,细胞间距增加,尼氏染色减弱;造模3和7 d的大鼠细胞体积明显缩小,细胞间隙明显增大,尼氏染色加深,CA1及CA3细胞数量明显减少;造模14 d和28 d的大鼠神经元体积逐渐向正常恢复,但仍较Control组小。免疫组化结果显示:GPER1免疫阳性细胞以海马锥体细胞和齿状回颗粒细胞为主,主要分布在细胞膜。与Control组相比,造模2 d和3 d的大鼠海马CA1及CA3区GPER1表达增加(P 0. 05),7 d后增加最明显(P 0. 01),14、28 d后表达下降;在DG区,造模3 d及7 d的大鼠GPER1表达增加(P 0. 05),14 d后表达下降(P 0. 05),28 d大鼠无显著差异。Western Blot结果显示:与Control组比较,造模2 d和3 d的大鼠GPER1相对表达量开始增高,7 d后明显增高(P 0. 05),14 d及28 d的大鼠表达降低。结论:GPER1在海马神经元的表达随着神经元损伤的加重而增高,随着神经元损伤的恢复逐渐降低,提示其表达变化与神经元的损伤与修复有关。     

ASIC1a和TASKs在大鼠癫痫持续状态模型中的作用

目的:探讨酸敏感离子通道1a(ASIC1a)、弱内向整流钾通道相关的酸敏感钾通道1和3(TASK-1和TASK-3)在大鼠癫痫持续状态(SE)中的表达及其在癫痫持续状态中的作用。方法:成年雄性SD大鼠随机分为对照组(control)和SE组,应用氯化锂-匹罗卡品诱导SE模型,采用real time RT-PCR和Western Blot技术分别检测海马组织ASIC1a、TASK-1和TASK-3在SE后0、1、2和3 h mRNA、蛋白表达水平,应用膜片钳技术观察SE后ASIC1a、TASK-1和TASK-3对海马CA1区锥体神经元兴奋性的影响。结果:在mRNA水平,与control组相比,SE组ASIC1a在2和3 h、TASK-1在1 h、TASK-3在3 h时间点表达显著减少。在蛋白水平,与control组相比,SE组ASIC1a、TASK-1和TASK-3在3 h时间点表达均显著降低。与SE control组相比,给予ASIC1a抑制剂后动作电位(AP)的频率明显降低,给予TASK-1和TASK-3抑制剂后,AP的频率均显著增加。结论:SE后大鼠海马区ASIC1a、TASK-1...     

Acute changes in the neuronal expression of GABA and glutamate decarboxylase isoforms in the rat piriform cortex following status epilepticus

The piriform cortex (PC) is the largest region of the mammalian olfactory cortex with strong connections to other limbic structures, including the amygdala, hippocampus, and entorhinal cortex. In addition to its functional importance in the classification of olfactory stimuli, the PC has been implicated in the study of memory processing, spread of excitatory information, and the facilitation and propagation of seizures within the limbic system. Previous data from the kindling model of epilepsy indicated that alterations in GABAergic inhibition in the transition zone between the anterior and posterior PC, termed here central PC, are particularly involved in the processes underlying seizure propagation. In the present study we studied alterations in GABAergic neurons in different parts of the PC following seizures induced by kainate or pilocarpine in rats. GABA neurons were labeled either immunohistochemically for GABA or its synthesizing enzyme glutamate decarboxylase (GAD) or by in situ hybridization using antisense probes for GAD65 and GAD67 mRNAs. For comparison with the PC, labeled neurons were examined in the basolateral amygdala, substantia nigra pars reticulata, and the hippocampal formation. In the PC of controls, immunohistochemical labeling for GABA and GAD yielded consistently higher neuronal densities in most cell layers than labeling for GAD65 or GAD67 mRNAs, indicating a low basal activity of these neurons. Eight hours following kainate- or pilocarpine-induced seizures, severe neuronal damage was observed in the PC. Counting of GABA neurons in the PC demonstrated significant decreases in densities of neurons labeled for GABA or GAD proteins. However, a significantly increased density of neurons labeled for GAD65 and GAD67 mRNAs was determined in layer II of the central PC, indicating that a subpopulation of remaining neurons up-regulated the mRNAs for the GAD isoenzymes. One likely explanation for this finding is that remaining GABA neurons in layer II of the central PC maintain high levels of activity to control the increased excitability of the region. In line with previous studies, an up-regulation of GAD67 mRNA, but not GAD65 mRNA, was observed in dentate granule cells following seizures, whereas no indication of such up-regulation was determined for the other brain regions examined. The data substantiate the particular susceptibility of the central PC to seizure-induced plasticity and indicate that this brain region provides an interesting tool to study the regulation of GAD isoenzymes.     

Loss of phase synchrony in an animal model of partial status epilepticus

Interrupting a focal, chronic infusion of GABA to the rat motor cortex initiates the progressive emergence of a sustained spiking electroencephalographic (EEG) activity, associated with myoclonic jerks of the corresponding body territory. This activity is maintained over several hours, has an average frequency of 1.5 Hz, is localized to the infusion site and never generalizes. The GABA withdrawal syndrome (GWS) has therefore features of partial status epilepticus. Changes in EEG signals associated with the GWS were studied in freely moving rats by measuring the phase synchrony between bilateral epidural records from the neocortex. Our results showed (i) epileptic activity was associated with a striking decrease in phase synchrony between all pairs of electrodes including the focus, predominantly in the 1-6 Hz frequency range. There was a mean decrease of 75.34+/-5.26% in phase synchrony levels between the period before GABA interruption and the period after epileptic activity appeared. (ii) This reduction in synchrony contrasted with an increase of power spectral density in the corresponding EEG channels over the same 1-6 Hz frequency range, (iii) neither changes in synchrony nor in nonlinear dynamics were detected before the first EEG spikes, (iv) systemic injection of ketamine, an antagonist of N-methyl-d-aspartic acid (NMDA) receptors, modified transiently both epileptic activity and the synchrony profile. (v) Spiking activity and synchrony changes were suppressed by reperfusion of GABA. Our data suggest that, during a partial status epilepticus, interactions between the epileptic focus and connected neocortical neuronal populations are dramatically decreased in low frequencies.     

Pilocarpine-induced status epilepticus causes acute interneuron loss and hyper-excitatory propagation in rat insular cortex

Recent clinical studies have shown that the insular cortex (IC) is involved in temporal lobe epilepsy and suggested that the IC mediates spreading of epileptic activity from the temporal lobe, including the hippocampus and amygdala, to the frontal cortex. However, little is known about anatomical and physiological features of the IC in models of temporal lobe epilepsy. The present study evaluated the distribution pattern of GABAergic interneurons, especially parvalbumin (PV)- and somatostatin (SS)-immunopositive neurons, and excitatory propagation pattern in the IC of rats 4–7 days and 2 months after pilocarpine-induced status epilepticus (4–7 d and 2 m post-SE rats, respectively). The number of PV-immunopositive neuron profiles in the agranular IC (AI) significantly decreased by 24.6% and 41.5% in 7 d and 2 m post-SE rats, respectively. The dysgranular and granular IC (DI+GI) exhibited only 5.2% loss of PV-immunopositive neurons in 7 d post-SE rats, while 2 m post-SE rats showed 30.4% loss of PV-immunopositive neurons. There was no significant change of the SS-immunopositive neuron profile numbers in the AI and DI+GI of 7 d and 2 m post-SE rats. The regions with decreased numbers of PV-immunopositive neuron profiles overlapped with those where many degenerating cells were detected by Fluoro-Jade B staining. The area of excitatory propagation responding to electrical stimulation of the caudal AI was expanded in 4–7 d post-SE rats, and excitation frequently propagated to the frontal cortex including the motor cortex. Optical signals in the AI of 4–7 d post-SE rats were larger in amplitude than those of controls. In contrast to the AI, the DI of 4–7 d post-SE rats showed similar excitatory propagation pattern and amplitude to that of controls. These results suggest that the region-specific loss of PV-immunopositive neurons occurred in the AI 4–7 d after pilocarpine-induced status epilepticus, which may play an important role in facilitating excitatory propagation in the IC.     

枫叶黄酮对老年痴呆动物模型的抗氧化作用及分子机制

目的:构建β淀粉样蛋白1-42(Aβ1-42)联合D-半乳糖(D-gal)致痴呆模型,探讨枫叶黄酮抗氧化作用的分子机制。方法:36只成年雄性Sprague Dawley(SD)大鼠随机分为3组:假手术组、模型组、治疗组。采用侧脑室注射β淀粉样蛋白1-42(Aβ1-42)联合腹腔注射D半乳糖(D-gal)构建SD大鼠痴呆模型后经枫叶黄酮治疗,采用Morris水迷宫实验(MWM)检测大鼠学习记忆能力;用化学比色法检测大脑皮质丙二醛(MDA)和内源性巯醇抗氧化物(酶):谷胱甘肽还原酶(glutathione reductase,GR)、谷胱甘肽(glutathione,GSH)、谷胱甘肽过氧化酶(glutathione peroxidase,GSH-PX)、超氧化物歧化酶(superoxide dismutase,SOD)的含量;免疫印迹法检测大脑皮质中丝裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)家族相关蛋白:细胞外信号调节蛋白激酶(extra-cellular signal-regulated protein kinase,ERK)、p38、c-Jun氨基末端激酶(c-Jun N-terminal kinase,JNK)的磷酸化水平。结果:模型组与假手术组比较:大鼠的逃避潜伏期明显延长(P<0.05),在第Ш象限逗留的时间明显减少(P<0.05),跨越平台次数明显减少(P<0.05);大脑皮质MDA含量增加(P<0.05),GR、GSH-PX的含量降低(P<0.05);p38、JNK磷酸化增强,ERK磷酸化水平降低。而枫叶黄酮治疗后:大鼠逃避潜伏期明显缩短(P<0.05),在第Ⅲ象限逗留的时间明显增加(P<0.05),跨越平台次数明显增加(P<0.05);大脑皮质MDA含量降低(P<0.05),GR、GSH-PX的含量升高(P<0.05);p38、JNK磷酸化被抑制,ERK的磷酸化增加。结论:枫叶黄酮能改善学习记忆能力,对抗大鼠神经系统衰老。其作用可能是通过上调痴呆模型大鼠大脑皮质内源性巯醇抗氧化物(酶)GR和GSH-PX的含量,抑制p38、JNK磷酸化并增强ERK磷酸化而实现的。     

P2X7 receptor regulates leukocyte infiltrations in rat frontoparietal cortex following status epilepticus

Background  

In the present study, we investigated the roles of P2X7 receptor in recruitment and infiltration of neutrophil during epileptogenesis in rat epilepsy models.     

Altered expression of voltage-gated potassium channel 4.2 and voltage-gated potassium channel 4-interacting protein, and changes in intracellular calcium levels following lithium-pilocarpine-induced status epilepticus

The A-type voltage-gated potassium channels (Kv4) have been proved to play a major role as modulators of somatodendritic excitability. Recent studies indicate that neuronal hyperactivity in epilepsy is associated with changes in Kv4. However, the precise regulation of Kv4 in the development of epilepsy and its underlying mechanism remain unclear. In this study, we investigated whether the expression of the Kv4.2 channel and of its major modulator, voltage-dependent potassium channel-interacting protein (KChIP1), is altered following lithium-pilocarpine induced status epilepticus (SE) and the chronic-epilepsy phase in the rat model. We found that Kv4.2 and KChIP1 expression was transiently up-regulated following SE, whereas it was down-regulated during the chronic phase: this was most prominent in the CA1 and CA3 regions. The time-course analysis of the protein expression level showed that the peak Kv4.2 up-regulation was between 6 and 24 h after SE, whereas KChIP1 expression was increased earlier and for a shorter period. The temporospatial changes in Kv4.2 were very similar to those of its major modulator KChIP1. We compared the difference in 4-aminopyridine (4-AP)-induced intracellular calcium ([Ca(2+)]i) elevation between model and control brain slices. The results showed that the [Ca(2+)]i elevation induced by the Kv4 channel blocker 4-AP was aggravated and prolonged in the model slice after SE. The functional relevance of these changes in Ca(2+) homeostasis and Kv4.2 and KChIP1 expression may be associated with intrinsic neuronal excitability regulation and epileptogenesis.     

In vivo MRS and histochemistry of status epilepticus‐induced hippocampal pathology in a juvenile model of temporal lobe epilepsy

Childhood status epilepticus (SE) initiates an epileptogenic process that leads to spontaneous seizures and hippocampal pathology characterized by neuronal loss, gliosis and an imbalance between excitatory and inhibitory neurotransmission. It remains unclear whether these changes are a cause or consequence of chronic epilepsy. In this study, in vivo MRS was used in a post‐SE juvenile rat model of temporal lobe epilepsy (TLE) to establish the temporal evolution of hippocampal injury and neurotransmitter imbalance. SE was induced in P21 rats by injection of lithium and pilocarpine. Four and eight weeks after SE, in vivo ¹H and γ‐aminobutyric acid (GABA)‐edited MRS of the hippocampus was performed in combination with dedicated ex vivo immunohistochemistry for the interpretation and validation of MRS findings. MRS showed a 12% decrease (p < 0.0001) in N‐acetylaspartate and a 15% increase (p = 0.0226) in choline‐containing compound concentrations, indicating neuronal death and gliosis, respectively. These results were confirmed by FluoroJade and vimentin staining. Furthermore, severe and progressive decreases in GABA (?41%, p < 0.001) and glutamate (Glu) (?17%, p < 0.001) were found. The specific severity of GABAergic cell death was confirmed by parvalbumin immunoreactivity (?68%, p < 0.001). Unexpectedly, we found changes in glutamine (Gln), the metabolic precursor of both GABA and Glu. Gln increased at 4 weeks (+36%, p < 0.001), but returned to control levels at 8 weeks. This decrease was consistent with the simultaneous decrease in glutamine synthase immunoreactivity (?32%, p = 0.037). In vivo MRS showed gliosis and (predominantly GABAergic) neuronal loss. In addition, an increase in Gln was detected, accompanied by a decrease in glutamine synthase immunoreactivity. This may reflect glutamine synthase downregulation in order to normalize Gln levels. These changes occurred before spontaneous recurrent seizures were present but, by creating a pre‐epileptic state, may play a role in epileptogenesis. MRS can be applied in a clinical setting and may be used as a noninvasive tool to monitor the development of TLE. Copyright © 2012 John Wiley & Sons, Ltd.