新生期大鼠反复痫性发作的形态学及行为学结果与糖皮质激素水平升高有关(英文)

目的探讨新生期大鼠反复痫性发作后的形态学,行为学以及糖皮质激素水平的变化。方法64只出生后一天的Wistar大鼠随机分为惊厥组40只和对照组24只。惊厥组的新生鼠在出生后1天(P1)、4天(P4)、7天(P7)给予腹腔注射匹罗卡品,制备新生鼠癫痫模型;对照组的新生鼠腹腔注射生理盐水。惊厥组分别在第 3次致痫后在即刻(Ⅰ组)、第4 天(Ⅱ组)、第14 天(Ⅲ组)、第42天(Ⅳ组)四个时间点处死,各时间点设相应对照组,处死前36 h惊厥组和对照组的大鼠腹腔注射BrdU。所有大鼠处死前均取血检测糖皮质激素。第Ⅳ组从P40开始进行Morris水迷宫试验。结果新生鼠3次发作后即刻和第4天与相应日龄对照组相比,齿状回BrdU阳性细胞数明显减少(P<0.05),而癫痫发作后14天和42天BrdU阳性细胞数增加,但发作后14天差异无统计学意义(P>0.05)。在4天的Morris水迷宫试验中,匹罗卡品处理组大鼠到达平台的时间均长于对照组,但是只有第1天和第2天有统计学意义(P<0.05)。检测结果表明高水平的糖皮质激素一直持续到发作后第4天,糖皮质激素水平与BrdU阳性细胞数呈负相关。结论新生大鼠反复痫性发作会造成早期神经发生减少,而后期神经发生增加;造成大鼠成年后认知功能缺陷;造成糖皮质激素水平增高,这与痫性大鼠形态学和行为学方面的改变有关。     

匹罗卡品诱发成年大鼠普遍癫痫与难治性癫痫海马神经发生的变化

背景：神经发生包括细胞增殖、迁移、分化和存活等,是人和多数哺乳动物部分脑区产生新生神经元的过程,主要分布在侧脑室下区和海马齿状回。癫痫可导致海马齿状回的神经发生改变,BrdU是目前公认最理想检测未成熟细胞增殖的标记物之一。 目的：观察匹罗卡品诱发成年大鼠癫痫后神经发生的特点,以及普通癫痫与难治性癫痫神经发生的差异。 设计、时间及地点：随机分组,细胞分子生物学实验,于2006-08/2007-06在华中科技大学同济医学院中心实验室及附属协和医院中心实验室完成。 材料：选用健康Sprague-Dawley雄性大鼠100只,随机分为2组,对照组8只,实验组92只,分为普通癫痫组,自发发作组,难治性癫痫组和非耐药组。匹罗卡品为武汉晶美公司产品,兔抗鼠BrdU抗体为美国sigma公司产品,辣根过氧化物酶标记的羊抗兔IgG为武汉博士德公司产品。 方法：对照组大鼠腹腔注射生理盐水;实验组腹腔注射匹罗卡品15mg/kg,最多注射4次,出现癫痫持续状态的大鼠注射水合氯醛终止发作。致癫大鼠癫痫发作终止后6h腹腔注射BrdU,观察自发发作情况。以脑电图、自发发作频率持续时间,无自发发作为普通癫痫组,有自发发作为自发发作组。行卡马西平灌胃2周并记录发作频率,对卡马西平治疗无效,发作频率减少<50%的为难治性癫痫组,治疗有效即发作频率减少>50%为非耐药组。普通癫痫组分别于注射后第1,2,3,7,14,21和28d取鼠脑海马部做冠状连续切片。非耐药组和难治性癫痫组的大鼠,再次行腹腔注射BrdU,每次为50mg/kg,连续注射4次,每次间隔2h,48h后取脑海马部制作石蜡切片。 主要观察指标：脑海马部切片行免疫组化染色,镜下观察不同时间点BrdU阳性细胞的分布、形态和数量及注射匹罗卡品后大鼠癫痫发作状况。 结果：匹罗卡品第1次注射后所有大鼠无癫痫发作,第2次注射发作16只,第3次注射发作42只,第4次注射后发作11只,14只大鼠4次注射仍无癫痫发作,9只大鼠癫痫持续状态后死亡,77只进入结果分析。神经发生主要位于海马颗粒细胞层和齿状回。与对照组比较,普通癫痫组BrdU阳性细胞明显增多（P<0.01）,难治性癫痫组新生细胞较普通癫痫组明显减少（P<0.01）,神经发生减少。癫痫后第2天BrdU 阳性细胞数目开始增加,14-15d达到高峰,1个月后回到初始水平。 结论：与普通癫痫相比,难治性癫痫可导致神经发生减少。     

不同程度的性发作对成年大鼠空间学习记忆影响的研究

目的研究不同程度的性发作对成年大鼠空间学习记忆的影响。方法采用氯化锂和匹罗卡品联合诱导大鼠不同程度的癫模型(轻型和重型)。于造模后第6d给所有大鼠腹腔注射5-溴脱氧尿苷嘧啶(BrdU+)标记海马齿状回增殖的内源性神经前体细胞;用免疫组化方法观察各组大鼠注射BrdU+后第1d和第28d齿状回BrdU+阳性细胞数以及第28d的BrdU+/神经元核性蛋白(NeuN+)阳性细胞数及分布情况;利用Morris水迷宫评价大鼠的学习记忆功能。结果与正常组及轻型组比较,在各个时间点重型组海马齿状回BrdU+细胞数均增加(P<0.05),28d时BrdU+/NeuN+细胞数相应增多,但其占BrdU+细胞数的比例明显下降(P<0.05)。28d时重型组大鼠的学习记忆功能较正常组及轻型组明显下降(P<0.05)。结论严重的癫发作造成大鼠对空间学习记忆功能的损害,可能与其刺激大鼠海马齿状回内源性神经前体细胞增殖水平,抑制其分化为新生的成熟神经元有关。     

复智散对阿尔茨海默病大鼠海马内源性神经干细胞增殖的影响

目的观察复智散（FZS）对Alzheimer病（AD）模型大鼠海马齿状回内源性神经干细胞增殖的影响。方法采用β淀粉样蛋白25—35（Aβ25—35）侧脑室注射制作AD大鼠模型。采用Morris水迷宫检测大鼠的学习记忆能力,免疫荧光检测大鼠海马5-溴脱氧尿嘧啶（BrdU）阳性细胞表达,免疫组化检测海马增殖细胞核抗原（PCNA）阳性细胞表达,并对海马齿状回下颗粒层、海马门、分子层分别进行BrdU、PCNA阳性细胞计数。结果与模型组比较,健康对照组、假手术组和FZS治疗组大鼠水迷宫实验中的平均逃避潜伏期缩短（P〈0．05）,齿状回颗粒细胞下层BrdU、PCNA阳性细胞数量明显增加（P〈0．05）,但后三组之间比较差异无统计学意义。结论FZS可促进AD模型大鼠海马齿状回内源性神经干细胞增殖。     

卡马西平对匹罗卡品诱导成年癫间疒大鼠海马齿状回神经前体细胞增殖的影响

目的研究卡马西平对成年癫大鼠海马齿状回内源性神经前体细胞增殖的影响。方法采用氯化锂和匹罗卡品联合诱导大鼠癫模型,将癫大鼠随机分为癫对照组和癫卡马西平组,正常大鼠随机分为正常对照组和正常卡马西平组。癫对照组和正常对照组给以蒸馏水灌胃,同时癫卡马西平组和正常卡马西平组给予卡马西平灌胃。于灌胃后第6d腹腔注射5-溴脱氧尿苷嘧啶(BrdU)标记海马齿状回的内源性神经前体细胞的增殖情况;用免疫组化方法观察各组大鼠在注射BrdU后第1d、第7d齿状回BrdU阳性细胞数量的表达。结果①注射BrdU后第1d,癫对照组大鼠海马齿状回BrdU阳性细胞数较正常对照组明显增加(P<0.01),癫卡马西平组大鼠海马齿状回BrdU阳性细胞数较癫对照组减少(P<0.05);②注射BrdU后第7d,癫对照组大鼠海马齿状回BrdU阳性细胞数较正常对照组明显增加(P<0.01),癫卡马西平组大鼠海马齿状回BrdU阳性细胞数较癫对照组明显减少(P<0.05)。结论卡马西平抑制癫大鼠海马齿状回内源性神经前体细胞增殖。     

针刺任脉、督脉及膀胱经促进新生儿缺血缺氧性脑病鼠模型脑内神经干细胞增殖

目的检测针刺任脉、督脉及膀胱经对新生儿缺血缺氧性脑病（HIE）鼠模型脑内神经干细胞的影响，分析针刺诱导神经干细胞增殖的机制。方法新生7dSD大鼠结扎左侧颈总动脉并缺氧2h制作HIE鼠模型。动物分为针刺组和对照组。针刺组每天针刺任脉、督脉及膀胱经一次。对照组不作处理。各组动物每天两次腹腔注射BrdU用于标记脑内神经干细胞增殖情况，分别于模型建立后3d、7d、14d和28d取脑组织行抗BrdU的免疫组化染色。分别观察各组动物海马及皮层BrdU阳性细胞数目、形态以及分布情况：并比较他们之间的差异。结果抗BrdU的免疫组化染色显示针刺治疗第3天及第7天时针刺组动物皮层及海马的BrdU阳性细胞数目和对照组相比。差别无统计学意义；针刺治疗第14天及第28天时针刺组动物皮层及海马的BrdU阳性细胞数目明显比对照组多．差别有统计学意义。结论针刺任脉、督脉及膀胱经能促进HIE模型鼠皮层及海马神经干细胞的增殖潜能。     

次声对成年大鼠脑室下区神经前体细胞增殖的影响

目的探讨次声作用对成年大鼠脑室下区（SVZ）神经前体细胞增殖的影响。方法成年雄性Sprague-Dawley大鼠（n=24）随机分为正常对照组、对照组和次声组,次声组动物置于次声压力仓（16Hz、130dB）内连续作用7d（2h/d）。照射结束后,分别于3d、7d、10d和14d处死。处死前各组大鼠腹腔注射5-溴脱氧尿嘧啶尿苷（BrdU）3次,以BrdU免疫组织化学法检测各组SVZ内增殖细胞数目的变化。结果次声照射结束后3d,次声处理组动物SVZ区的BrdU阳性细胞数目较对照组显著减少（P〈0.01）,7d时阳性细胞数继续降低（P〈0.01）,但10d时开始逐渐恢复,14d时达到正常水平（P〉0.05）。结论16Hz、130dB次声可抑制成年大鼠SVZ神经前体细胞增殖。     

次声对成年大鼠齿状回神经前体细胞增殖的影响

目的研究次声对成年大鼠海马齿状回神经前体细胞增殖的影响。方法大鼠随机等分为正常对照组、假次声组和次声组（每组16只）。次声组暴露于8Hz、130dB次声环境7d（2h／d），暴露结束后第1、3、7、14d处死，采用抗5-溴脱氧尿嘧啶尿苷（BrdU）免疫组化方法，观察齿状回BrdU阳性细胞数的变化。结果次声作用结束后第1d，齿状回BrdU阳性细胞数与假次声组和正常对照组相比均无统计学差异；第3d及第7d，BrdU阳性细胞数减少（P〈0．05），第14d恢复正常水平。结论8Hz、130dB次声可抑制正常成年大鼠海马神经前体细胞增殖，可能与次声引起大鼠脑内微环境改变有关。     

锂-匹罗卡品致癫大鼠早期大脑皮质MyT1 mRNA表达变化

目的 探讨氟化锂-匹罗卡品致癫大鼠脑髓鞘转录因子1基因表达变化及其意义。方法 以氯化锂、匹罗卡品对雄性成年SD大鼠先后腹腔注射，制成癫痫持续状态动物模型；采用5′末端标记地高辛的寡核苷酸探针荧光原位核酸分子杂交检测癫性发作后早期大鼠大脑皮质MyT1 mRNA阳性细胞数量。结果 与对照组相比，癫痫后1d组大鼠脑皮质MyT1 mRNA阳性细胞数减少（P＜0.05）；其他各组大鼠脑皮质MyT1 mRNA阳性细胞数都有明显的增加，其中癫痫后7d和14d组MyT1mRNA阳性细胞数都有非常显著的增加（P＜0.05，P＜0.01）。结论 氯化锂-匹罗卡品致癫大鼠早期大脑MyT1 mRNA表达增加，并有时程性变化，提示与早期脑损伤修复有关。     

生天南星对匹罗卡品癫(痫)模型鼠GABA能神经元的影响

目的:探讨生天南星对匹罗卡品癫(痫)模型鼠γ-氨基丁酸(GABA)表达的影响.方法:选取50只健康SD大鼠,采用腹腔注射氯化锂125 mg后予腹腔注射匹罗卡品150mg/kg,建立癫(痫)大鼠模型,获得Ⅲ级以上发作后,作为造模成功;癫(痫)造模成功后随机分成5组(癫闻模型组、丙戊酸钠治疗组、生天南星低剂量治疗组、生天南星中剂量治疗组、生天南星高剂量治疗组)给药4周后,麻醉处理后留取大鼠海马标本.采用免疫组织化学法,检测各组大鼠海马区GABA能神经元.结果:除空白对照组无癫(痫)样发作外,其余各组都出现Racine分级中的Ⅲ-V级(痫)样发作表现.丙戊酸钠治疗组、治疗各剂量生天南星治疗组GABA表达上调,与模型组比较,差异有显著意义(P＜0.01).结论:生天南星对氯化锂-匹罗卡品癫(痫)模型大鼠海马区内抑制性细胞GABA神经元有明显的上调作用,从而起到抑制神经元兴奋,抑制癫(痫)样过度放电、缓解癫(痫)症状的作用.     

Consequences of pilocarpine-induced recurrent seizures in neonatal rats

Accumulated evidence have shown that a series of morphological alternations occur in patients with epilepsy and in different epileptic animal models. Given most of animal model studies have been focused on adulthood stage, the effect of recurrent seizures to immature brain in neonatal period has not been well established. This study was designed to observe the certain morphological changes following recurrent seizures occurred in the neonatal rats. For seizure induction, neonatal Wistar rats were intraperitoneally injected with pilocarpine on postnatal day 1 (P1), P4 and P7. Rat pups were grouped and sacrificed at 1d, 7d, 14d and 42d after the last pilocarpine injection respectively. Bromodeoxyuridine (BrdU) was intraperitoneally administered 36h before the rats were sacrificed. BrdU single and double labeling with neuronal markers were used to analyze cell proliferation and differentiation. Nissl and Timm staining were performed to evaluate cell loss and mossy fiber sprouting. Rats with neonatal seizures had a significant reduction in the number of Bromodeoxyuridine-(BrdU) labeled cells in the dentate gyrus compared with the control groups when the animals were killed either 1 or 7 days after the third seizure (P<0.05) but there was no difference between two groups on P21. On the contrary, BrdU-labeled cells significantly increased in the experimental group compared with control group on P49 (P<0.05). The majority of the BrdU-labeled cells colocalized with neuronal marker-NF200 (Neurofilament-200). Nissl staining showed that there was no obvious neuronal loss after seizure induction over all different time points. Rats with the survival time of 42 days after neonatal seizures developed to increased mossy fiber sprouting in both the CA3 region and supragranular zone of the dentate gyrus compared with the control groups (P<0.05). Taken together, the present findings suggest that synaptic reorganization only occurs at the later time point following recurrent seizures in neonatal rats, and neonatal recurrent seizures can modulate neurogenesis oppositely over different time window with a down-regulation at early time and up-regulation afterwards.     

Suppression of hippocampal neurogenesis is associated with developmental stage, number of perinatal seizure episodes, and glucocorticosteroid level

Seizures increase dentate granule cell proliferation in adult rats but decrease proliferation in young pups. The particular period and number of perinatal seizures required to cause newborn granule cell suppression in development are unknown. Therefore, we examined cell proliferation with bromodeoxyuridine (BrdU) immunohistochemistry during the peak of neurogenesis (e.g., P6 and P9) and at later postnatal ages (e.g., P13, P20, or P30) following single and multiple episodes of perinatal status epilepticus induced by kainate (KA). Because an inverse relationship exists between glucocorticosteroids (CORT) levels and granule cell proliferation, plasma CORT levels and electroencephalographic (EEG) activity were simultaneously monitored to elucidate underlying mechanisms that inhibit cell proliferation. In control animals, the number of BrdU-labeled cells increased then declined with maturation. After 1x KA or 2x KA administered on P6 and P9, the numbers of BrdU-labeled cells were not different from age-matched controls. However, rat pups with 3x KA (on P6, P9, and P13) had marked suppression of BrdU-labeled cells 48-72 h after the last seizure (43 +/- 6.5% of control). Cell proliferation was also significantly inhibited on P20 after 2x KA (to 56 +/- 6.9%) or 3x KA (to 54 +/- 7.9%) and on P30 with 3x KA (to 74.5 +/- 8.2% of age-matched controls). Cell death was not apparent as chromatin stains showed increased basophilia of only inner cells lining the granule cell layers, in the absence of eosinophilia, argyrophilia, or terminal deoxynucleotidyl dUTP nick endlabeling (TUNEL) labeling at times examined. In P13 pups with 3x KA, electron microscopy revealed an increased number of immature granule cells and putative stem cells with irregular shape, condensed cytoplasm, and electron dense nuclei, and they were also BrdU positive. The EEG showed no relationship between neurogenesis and duration of high-synchronous ictal activity. However, endocrine studies showed a correlation with BrdU number and age, sustained increases in circulating CORT levels following 1x KA on P6 (0.7 +/- 0.1 to 2.40 +/- 0.86 microg/dl), and cumulative increases that exceeded 10 microg/dl at 4-8 h after 3x KA on P13 or P20. In conclusion, a history of only one or two perinatal seizure(s) can suppress neurogenesis if a second or third seizure recurs after a critical developmental period associated with a marked surge in CORT. During the first 2 weeks of postnatal life sustained increases in postictal circulating CORT levels but not duration or intensity of ictal activity has long-term consequences on neurogenesis. The occurrence of an increased proportion of immature granule cells and putative stem cells with irregular morphology in the absence of neurodegeneration suggests that progenitors may not differentiate properly and remain in an immature state.     

Pentylenetetrazol-induced recurrent seizures in rat pups: time course on spatial learning and long-term effects

PURPOSE: Recurrent seizures in infants are associated with a high incidence of neurocognitive deficits. Animal models have suggested that the immature brain is less vulnerable to seizure-induced injury than is that in adult animals. We studied the effects of recurrent neonatal seizures on cognitive tasks performed when the animals were in adolescence and adulthood. METHODS: Seizures were induced by intraperitoneal injection of pentylenetetrazol (PTZ) for 5 consecutive days, starting from postnatal day 10 (P10). At P35 and P60, rats were tested for spatial memory by using the Morris water maze task. In adulthood, motor performance was examined by the Rotarod test, and activity level was assessed by the open field test. Seizure threshold was examined by inhalant flurothyl. To assess presence or absence of spontaneous seizures, rats were video recorded for 4 h/day for 10 consecutive days for the detection of spontaneous seizures. Finally, brains were examined for histologic evidence of injury with cresyl violet stain and Timm staining in the supragranular zone and CA3 pyramidal cell layers of the hippocampus. RESULTS: PTZ-treated rats showed significant spatial deficits in the Morris water maze at both P35 and P60. There were no differences in seizure threshold, motor balance, or activity level during the open field test. Spontaneous seizures were not recorded in any rat. The cresyl violet stain showed no cell loss in either the control or experimental rats. PTZ-treated rats exhibited more Timm staining in the CA3 subfield. However, the control and experimental rats showed similar Timm staining within the supragranular zone. CONCLUSIONS: Our findings indicate that recurrent PTZ-induced seizures result in long-term cognitive deficits and morphologic changes in the developing brain. Furthermore, these cognitive deficits could be detected during pubescence.     

Effect of neonatal isolation on outcome following neonatal seizures in rats--the role of corticosterone

Emerging evidence indicates that early maternal care permanently modifies the activity of hypothalamic-pituitary-adrenal (HPA) axis and is a critical factor in determining the capacity of the brain to compensate for later encountered insults. The purpose of this study was to determine the role of corticosterone (CORT) in the detrimental effects of neonatal isolation (NI) on seizures. Rats were assigned randomly to the following five groups: (1) control (CONT) rats; (2) NI rats that underwent daily separation from their dams from postnatal day 2 (P2) to P9; (3) status epilepticus (SE) rats, induced by lithium-pilocarpine (Li-Pilo) model at P10; (4) NI plus SE (NIS) rats and (5) NISM rats, a subset of NIS rats receiving metyrapone (100 mg/kg), a CORT synthesis inhibitor, immediately after SE induction. At P10, plasma CORT levels were compared at baseline in CONT and NI rats and in response to Li-Pilo-induced SE among SE, NIS and NISM rats. We evaluated the spatial memory in the Morris water maze at P50 approximately 55, the expression of hippocampal cyclic adenosine monophosphate (cAMP)-responsive element-binding protein phosphorylation at serine-133 (pCREBSer-133) at P55, hippocampal neuronal damage at P80 and seizure threshold at P100. The isolated rats exhibited higher CORT release in response to SE than non-isolated rats, and the NIS rats had greater cognitive deficits and decreased seizure threshold compared to the CONT, NI and SE groups. By contrast, the NISM group, compared to the NIS group, showed a normal CORT response to SE and better spatial memory but no difference in seizure threshold. Compared to the CONT group, the hippocampal pCREBSer-133 level was significantly reduced in all experimental groups (NI, SE, NIS, NISM) with no differences between groups. All rats were free of spontaneous seizures later in life and had no discernible neuronal loss in the hippocampus. Results in this model demonstrate repetitive NI enhances response of plasma CORT to SE, and exacerbates the neurological consequences of neonatal SE. Amelioration of neurological sequelae following reduction of the SE-induced excessive rise in plasma CORT implicates CORT in the pathogenesis of NI increasing the vulnerability to seizures.     

Mossy fiber sprouting after recurrent seizures during early development in rats

In some children, epilepsy is a catastrophic condition, leading to significant intellectual and behavioral impairment, but little is known about the consequences of recurrent seizures during development. In the present study, we evaluated the effects of 15 daily pentylenetetrazol-induced convulsions in immature rats beginning at postnatal day (P) 1, 10, or 60. In addition, we subjected another group of P10 rats to twice daily seizures for 15 days. Both supragranular and terminal sprouting in the CA3 hippocampal subfield was assessed in Timm-stained sections by using a rating scale and density measurements. Prominent sprouting was seen in the CA3 stratum pyramidale layer in all rats having 15 daily seizures, regardless of the age when seizures began. Based on Timm staining in control P10, P20, and P30 rats, the terminal sprouting in CA3 appears to be new growth of axons and synapses as opposed to a failure of normal regression of synapses. In addition to CA3 terminal sprouting, rats having twice daily seizures had sprouting noted in the dentate supragranular layer, predominately in the inferior blade of the dentate, and had a decreased seizure threshold when compared with controls. Cell counting of dentate granule cells, CA3, CA1, and hilar neurons, with unbiased stereological methods demonstrated no differences from controls in rats with daily seizures beginning at P1 or P10, whereas adult rats with daily seizures had a significant decrease in CA1 neurons. Rats that received twice daily seizures on P10–P25 had an increase in dentate granule cells. This study demonstrates that, like the mature brain, immature animals have neuronal reorganization after recurrent seizures, with mossy fiber sprouting in both the CA3 subfield and supragranular region. In the immature brain, repetitive seizures also result in granule cell neurogenesis without loss of principal neurons. Although the relationship between these morphological changes after seizures during development and subsequent cognitive impairment is not yet clear, our findings indicate that during development recurrent seizures can result in significant alterations in cell number and axonal growth. J. Comp. Neurol. 404:537–553, 1999. © 1999 Wiley-Liss, Inc.     

新生期惊厥对大鼠海马NR1和GABAARα1表达的长期影响

目的 研究新生期惊厥对大鼠海马N-甲基-D-天门冬氨酸(NMDA)受体1(NR1)和γ-氨基丁酸A受体α1亚单位(GABAARα1)表达的长期影响,以期揭示发育期惊厥导致成年大鼠惊厥阈降低的机制.方法 生后6 d的Wistar大鼠48只采用完全随机法分成三氟乙醚吸入惊厥组和对照组,每组各24只,惊厥组再细分为单次惊厥组(诱导惊厥一次,持续30 min)和反复惊厥组(每天诱导惊厥一次,持续30 min,连续6 d),对照组同样操作但不吸入三氟乙醚.分别于惊厥后第7天和第75天取大鼠海马,匀浆提取膜蛋白,应用免疫印记法测定NR1、GABAARα1蛋白表达.结果 单次惊厥组和反复惊厥组75 d的海马NR1表达无显著变化,而反复惊厥组7 d的海马NR1表达较对照组显著增加(P＜0.05).同时,与对照组相比,GABAARα1亚单位在单次惊厥组第75天以及反复惊厥组的表达均有统计学意义(P＜0.05).结论 新生期大鼠反复或单次长程惊厥持续状态能够对海马NR1和GABAARα1表达产生远期影响,这种改变可能在发育期惊厥导致的脑兴奋性提高和惊厥阈降低中起重要作用.     

Persistent Effects of Maternal Deprivation on HPA Regulation Can Be Reversed By Feeding and Stroking, But Not By Dexamethasone

Maternal deprivation of neonatal rats for 24 h has immediate and persistent effects on hypothalamic-pituitary-adrenal (HPA) regulation. Immediately after deprivation corticosterone (CORT) is elevated. The primary purpose of our experiments was to determine if, by preventing this CORT elevation, the persistent effects could be reversed. In experiment 1, pups were injected with dexamethasone at the onset of the 24-h deprivation period on postnatal day 11 to suppress the rise in CORT. In experiment 2 some aspects of maternal behaviour known to suppress CORT levels were mimicked during deprivation from postnatal days 11-12. The pups were either: (1) left undisturbed; (2) stroked periodically; or (3) stroked and episodically fed. At postnatal day 20 basal and stress-induced adrenocorticotrophic hormone (ACTH) and CORT levels were measured as well as brain mineralocorticoid (MR) and glucocorticoid receptors (GR). Neonatal rats receiving dexamethasone prior to the onset of the deprivation on day 11 did not differ on day 20 from deprived pups that were exposed to elevated CORT levels. There were no detectable changes in the non-deprived pups that were treated with dexamethasone. In contrast, feeding and stroking during the period of deprivation obliterated the persistent effects both with regard to the reduced ACTH response and the decreased GR mRNA in hippocampus and hypothalamus. Stroking alone appears to have no influence. In conclusion, the persistent reduction of the ACTH response to mild stress and the decrease of GR mRNA is not mediated by deprivation-induced elevations in CORT, but appears to be reversible by reinstating specific aspects of the dam's nurturing behaviour.     

Spontaneous recurrent seizure following status epilepticus enhances dentate gyrus neurogenesis

It is known that evoked seizures can increase neurogenesis in the dentate gyrus in adult rats. Whether spontaneous seizures occurring after status epilepticus (SE) also results in alterations in neurogenesis is not known. Here, we measured neurogenesis in rats with and without spontaneous seizures following SE. Lithium-pilocarpine was used to induce seizures in postnatal (P) day 20 rats. Spontaneous seizure frequency was assessed 2 months using video monitoring. Rats then received bromodeoxyuridine to label dividing DNA and were sacrificed 24 h later. Animals with spontaneous seizures (n = 9) had a modest increase in neurogenesis compared to animals with SE (n = 6) and no spontaneous seizures and control rats (n = 10). These findings demonstrate that the hippocampus is capable of generating new neurons weeks following SE and further that recurrent seizures enhance the production of new neurons. These alterations in neurogenesis may contribute to ongoing pathological changes week and months following SE.