Pinealectomy stimulates and exogenous melatonin inhibits harmful effects of epileptiform activity during pregnancy in the hippocampus of newborn rats: an immunohistochemical study

Objectives Epilepsy during the pregnancy is an important problem in clinical practice for newborn individuals. Recently, it has been demonstrated that mothers’ epileptic seizures have some harmful effects on newborns, but present data concerning the effects of epileptic phenomena in pregnant mothers on newborn pups are still limited. The current study was undertaken to investigate the morphological changes in the hippocampus of newborn pups of pinealectomized rats subjected to experimental epilepsy during pregnancy.Methods In this study, rats were randomly divided into four groups (ten animals each): intact control group, epilepsy control group, surgical pinealectomy + epilepsy group, and group with melatonin treatment following pinealectomy procedure. The animals in surgical pinealectomy + epilepsy and melatonin treatment groups underwent a surgical intervention consisting of pineal gland removal. At 1 month after surgical pinealectomy, an acute grand mal epileptic seizure was induced by 400 IU penicillin G administration into their hippocampal CA3 region on the 13th day of their pregnancy in all animals except the intact control animals. On the first neonatal day, the hippocampi were removed and processed for microscopic examination. Nestin expression was analysed in the developing hippocampal tissue.Results Normal migration and hippocampal maturation were determined in the postnatal rat hippocampus in intact control group, but the morphological structure of the hippocampus in the epilepsy control group corresponded to the early embryonal period. It was found that experimental epilepsy and pinealectomy enhanced nestin immunoreactivity, whereas exogenous melatonin treatment (30 μg/100 g body weight, intraperitoneal) inhibited pinealectomy-stimulated nestin expression in CA1 region of the hippocampus.Conclusion These findings suggest that epileptic seizures during pregnancy may cause an impaired hippocampal neurogenesis and neuronal maturation in the newborn, and the negative effects in the postnatal rat hippocampus are more dramatic after pinealectomy of the mother; conversely, melatonin administration suppresses these negative changes. This is the first report investigating the effects of maternal epilepsy during pregnancy in pinealectomized rats on nestin immunoexpression in the newborn rat hippocampus.Presented in part at the 4th Asian-Pacific International Congress of Anatomists (APICA), Kuşadası, Turkey, 7-10 September 2005.     

The effect of experimental epilepsy induced by penicillin administration during pregnancy on nestin expression in the immature rat cerebellum

Introduction Recent knowledge regarding the effect of epileptic seizures in pregnant women on newborns was limited and, therefore, it was difficult to suggest the proper clinical guidelines and to take precautions against it. Studies evaluating the morphological effects of epileptic seizure during pregnancy on newborns in various experimental models are valuable. Therefore, the current study was designed to investigate the morphological changes in the cerebellum of newborn pups of rats subjected to experimental epilepsy during pregnancy.Materials and methods Swiss Albino rats were divided into three groups (six animals in each). In the first group (experimental group) an acute grand mal epileptic seizure was induced by 400 IU penicillin-G administration into their intrahippocampal CA3 region with a stereotaxic device during the 13th day of their pregnancy. The second group (intrahippocampal saline-injected sham group) and the third group (untreated animals) were the control groups. On the 1st neonatal day, pups were perfused with intracardiac fixative solution under anesthesia, and newborn cerebellums were dissected surgically for light and electron microscopic studies.Results In an immunohistochemical study using Rat-401 monoclonal antibody and peroxidase, the intermediate filament nestin was detected in the developing cerebellar tissue. Histologically, normal migration and cerebellar maturation were determined in the newborn rat cerebellum in the control and sham-operated groups. It was observed that the morphological structure of the cerebellar cortex in the experimental group was compromised in the early embryonal period. In contrast to the control and sham groups, it was found that nestin (+) cell density was increased in the experimental epilepsy group.Conclusions It has been concluded that epileptic convulsions during embryonic life may cause early neurogenesis and delayed maturation, which explains the harmful effects of epileptic grand mal seizures, hypoxia, and obstetric trauma to the embryo at the early stage of neuronal differentiation. However, further studies are necessary to investigate epileptic pregnant phenomena and to characterize the possible relationship between epilepsy and congenital malformations as well as mental retardation.     

依达拉奉对海人酸致颞叶癫痫大鼠海马神经元的保护作用

目的本实验观察依达拉奉对海人酸致痫大鼠海马神经元损伤的保护作用。方法选用成年健康雄性Wistar大鼠18只,体重260±20g。实验动物随机分为3组,①sham组(n=6):右侧海马CA3区注入等量的生理盐水;②KA模型组(n=6):右侧海马CA3区注入KA 4μg.kg-1(4μg/μl);③依达拉奉组(n=6):右侧海马CA3区注入KA 4μg.kg-1(4μg/μl)后,即刻给予依达拉奉10mg.kg-1.d-1腹腔注射。于大鼠注药或假手术后立即观察各组大鼠的行为学表现,于7d断头取脑,石蜡切片进行硫堇染色,于光学显微镜下观察注药对侧(左侧)海马CA1、CA3区及CA4门区组织形态学特征,并对其进行组织学分级。结果 Sham组大鼠注射对侧海马CA1、CA3和CA4门区无明显组织损伤,组织学分级多为0～1级,ND值为198±20.62和212±30.14;模型组KA致痫大鼠可见明显的组织损伤,组织学分级多为2～3级,ND值为79±13.72和90±14.98,与sham组相比,组织学分级显著升高(p<0.05),ND值显著降低(p<0.01)。依达拉奉组大鼠海马CA1区可见少量、散在性神经元坏死,组织学分级多1～2级,ND值为101±16.85和135±12.17。与模型组相比,组织学分级降低(p<0.05),ND值显著升高(p<0.05)。结论依达拉奉能够减轻KA致痫大鼠海马神经元的损伤,对神经元具有保护作用。     

戊四氮致痫对大鼠海马星形胶质细胞的影响

目的　探讨戊四氮（ＰＴＺ）致痫对大鼠海马星形胶质细胞的影响。方法　应用免疫组织化学方法观察ＰＴＺ致痫后大鼠海马内胶原纤维酸性蛋白（ＧＦＡＰ）变化的特点,同时观察了不同强度的痫性发作与ＧＦＡＰ改变的关系。结果　ＧＦＡＰ改变于ＰＴＺ致痫后１２ｈ 开始,２４ｈ 达到高峰,７２ｈ 已开始回落,并且痫性发作的强度与ＧＦＡＰ改变有一定的联系。结论　癫痫与星形细胞之间确有一定联系。     

Postnatal development of nestin positive neurons in rat basal forebrain: Different onset and topography with choline acetyltransferase and parvalbumin expression

Our previous studies identified a sub-population of cholinergic neurons which express nestin in the rostral part of the basal forebrain (BF) in normal adult rats. In the present study, the postnatal developmental patterns of nestin, choline acetyl transferase (ChAT) and parvalbumin (PV) positive neurons were explored by means of immunohistochemistry combined with immunofluorescence double label methods. Compared with early onset of ChAT expression (from P1) and delayed onset of PV expression (from P16), nestin positive activity was detected in the BF from P9 and co-expressed by parts of the ChAT positive neurons within the same region during the whole postnatal development process. However, ChAT and PV were not coexpressed by the neurons within the medial septum-diagonal band of Broca (MS-DBB) of BF. These results might imply a composite of separate development patterns displayed by different subpopulations of cholinergic neurons (nestin positive cholinergic neurons and nestin negative cholinergic neurons) within this region. Moreover, the topographic distribution of nestin, ChAT and PV positive neurons also showed different characteristics. In summary, our present study revealed a remarkable timing and topographic difference on the postnatal development of the nestin expression within the MS-DBB of BF compared with ChAT and PV expression. It is further suggested that nestin is re-expressed by cholinergic neurons in the BF after differentiation but not persisted from neuronal precursor cells.     

Retinal gliopathy accompanying thioacetamide-induced liver insufficiency: light and electron microscopic observations

A recent examination of retinae of patients who had died with symptoms of liver insufficiency (LI) including hepatic encephalopathy (HE) revealed morphological changes in retinal Müller glia similar to the astrocytic changes normally accompanying HE, and the term “hepatic retinopathy” (HR) was coined to define these changes. In the present study, the immunomorphology and ultrastructure of Müller cells were examined in rats in which LI with accompanying HE was induced with a hepatotoxin, thioacetamide (TAA). Light microscopically, retinae of rats with LI were characterized by swelling of the Müller cell cytoplasm. Immunostaining for glia-specific marker proteins in Müller cells from LI rats revealed a strongly enhanced expression of glial fibrillary acidic protein, and a considerable increase in glutamine synthetase immunoreactivity, as compared to control animals. Ultrastructurally, the Müller cells of LI rats showed swelling and vacuolization of cell processes. In particular, the endfeet contained many swollen mitochondria. By contrast, LI produced no morphologically demonstrable changes in retinal neurons and photoreceptor cells. Thus, the retinal changes induced by TAA in the rats strongly resembled those described in human HR, rendering the present rat model suitable for more detailed investigations of the pathomechanism(s) of HR. Received: 4 August 1997 / Revised, accepted: 12 January 1998     

Temporal profile of nestin expression after focal cerebral ischemia in adult rat

Nestin is an intermediate filament protein, transiently and abundantly expressed early in embryogenesis, e.g., in neuroepithelial cells, radial glia, germinal matrix cells and vascular cells. In the adult rat brain, nestin is only present in endothelial and select subventricular cells. We tested the hypothesis that after an experimental stroke, nestin expression is induced in glial cells and neurons. We measured the temporal profile of nestin expression after induction of focal cerebral ischemia in adult rats. Brain from rats (n=24) subjected to 2 h of transient middle cerebral artery occlusion (MCAo) and 3 h, 6 h, 12 h, 1 day, 2 days, 3 days, 7 days and 28 days (n=3, per time point) of reperfusion, and control sham operated (n=3) rats were processed for Western blotting to quantify nestin. Another set of brains from rats (n=28), subjected to 2 h of MCAo and 6 h, 12 h, 2 days, 7 days, 14 days, 21 days, and 28 days (n=4, per time point, except n=8 at 2 days) of reperfusion, and control sham operated (n=3) and normal (n=2) rats were processed by single and double labeled immunohistochemistry for cellular identification of nestin expression. By Western blotting, nestin within ischemic tissue increased slightly as early as 6 h, peaked at 7 days, and expression persisted for at least 4 weeks after 2 h of MCAo. By immunohistochemistry, nestin was expressed in astrocytes in the ischemic core from 6 to 12 h after MCAo. Nestin immunoreactivity was present in large numbers of astrocytes, and in scattered oligodendroglia and monocytes/macrophages in both the inner and outer boundary zones to the ischemic core at 1–7 days after MCAo. Nestin expression in glial cells declined at longer durations of survival, although for least 4 weeks after MCAo the nestin immunoreactivity delineated the boundary zone adjacent to the ischemic core. Nestin expression was present in some neurons localized to the outer boundary zone of the ischemic lesion in the cortex and striatum, and in most ependymal cells in the ventricular and subventricular zone (VZ/SVZ) from day 2 after MCAo and onward. The expression of nestin increased throughout the microvasculature in both the ischemic core and the boundary zone in all ischemic rats after 12 h of reperfusion. After stroke, nestin immunoreactivity in glial, neuronal and ependymal cells is suggestive of a protein expression pattern found in developing brain.     

Changes in neocortical and hippocampal GABAA receptor subunit distribution during brain maturation and aging

gamma-Aminobutyric acid type A (GABA(A)) receptors are the most important inhibitory receptors in the central nervous system, playing a pivotal role in the regulation of brain excitability. The pentameric receptor is commonly composed of different alpha, beta, and gamma subunits which mediate the function and pharmacology of the receptor and show regional- and temporal-specific expression patterns. Under varying physiological and pathophysiological conditions, this diversity allows a multitude of adaptive changes in subunit composition leading to distinct biological and pharmacological properties of the receptor. Here, we investigated the expression of five major GABA(A) receptors subunits (alpha1, alpha2, alpha3, alpha5, gamma2) in early postnatal, adult, and aged rat brains. Immunohistochemistry was performed at postnatal day 10, 30, 60, 90, 180, 360, and 540. Morphological and semi-quantitative evaluations of regional optical densities revealed specific regional and temporal expression patterns for all subunits. The study clearly demonstrated that changes in GABA(A) receptor distribution not only occur in the early postnatal cortex and hippocampal formation but also during later periods in the adolescent and aging brain. These findings contribute to a better understanding of age-related changes in brain excitability and further elucidate the distinct pharmacological effects of different GABAergic drugs in young and elderly patients.     

缺血性脑损伤诱导大鼠巢蛋白表达的实验研究

目的探讨缺血性脑损伤对内源性神经干细胞增殖、迁移的影响。方法选用健康雄性SD大鼠62只，随机分为正常组（6只）、脑缺血10min再灌流1、3、5、7、10、15、20d组（简称手术组，每时间点6只）、假手术对照组（14只，每时间点2只），参照Pulsinelli—Brierley方法制作短暂性全脑缺血动物模型：用SABC免疫组化法显示巢蛋白（nestin）阳性细胞；光镜下观察nestin阳性细胞的形态学变化并计数，半定量分析脑缺血损伤后内源性神经干细胞增殖、迁移的变化过程。结果手术组的nestin阳性细胞在缺血再灌流24h后表达增多，7～10d到高峰，15d时仍有显著表达；在室管膜下区的nestin阳性细胞有向皮质、海马迁移的迹象。结论缺血性脑损伤能诱导内源性神经干细胞增殖，这可能对脑损伤后的修复发挥作用。     

米诺环素对癫痫大鼠海马小胶质细胞的抑制作用

目的探讨米诺环素对癫痫大鼠海马小胶质细胞的抑制作用。 方法将40只雄性SD大鼠按随机数字表法分为4组：生理盐水组、青霉素组、米诺环素治疗组和米诺环素预处理组,每组各10只。大鼠腹腔注射青霉素G 740万～760万单位/kg以建立大鼠癫痫模型。免疫荧光组织化学技术检测大鼠造模后第1、3天海马小胶质细胞免疫反应性,Western blotting检测海马肿瘤生长因子-α(TNF-α)蛋白表达情况。 结果(1)癫痫发作可激活小胶质细胞。与青霉素组比较,大鼠癫痫发作后第1、3天米诺环素治疗组、米诺环素预处理组海马小胶质细胞活化、增生受抑制,差异均有统计学意义（P≤0.05）,且米诺环素预处理组抑制性更突出。(2)大鼠癫痫发作后第1、3天青霉索组、米诺环素治疗组、米诺环素预处理组TNF-α蛋白表达水平明显高于生理盐水组,差异均有统计学意义(P≤0.05);与青霉素组比较,米诺环素治疗组、米诺环素预处理组TNF-α蛋白表达水平降低,差异均有统计学意义(P≤0.05),且以米诺环素预处理组更明显。 结论米诺环素可有效抑制癫痫大鼠海马小胶质细胞活化、增生和炎症因子TNF-α的释放。     

Effects of prenatal binge-like ethanol exposure and maternal stress on postnatal morphological development of hippocampal neurons in rats

BackgroundAlcohol is one of the most commonly used drugs of abuse negatively affecting human health and it is known as a potent teratogen responsible for fetal alcohol syndrome (FAS), which is characterized by cognitive deficits especially pronounced in juveniles but ameliorating in adults. Searching for the potential morphological correlates of these effects, in this study, we compared the course of developmental changes in the morphology of principal hippocampal neurons in fetal-alcohol (A group), intubated control (IC group), and intact control male rats (C group) over a protracted period of the first two postnatal months.MethodsEthanol was administered to the pregnant Wistar dams intragastrically, throughout gestation days (GD) 7–20, at a total dose of 6 g/kg/day resulting in the mean blood alcohol concentration (BAC) of 246.6 ± 40.9 mg/dl. Ten morphometric parameters of Golgi-stained hippocampal neurons (pyramidal and granule) from CA1, CA3, and DG areas were examined at critical postnatal days (PD): at birth (PD1), at the end of the brain growth spurt period (PD10), in juveniles (PD30), and in young adults (PD60).ResultsDuring postnatal development, the temporal pattern of morphometric changes was shown to be region-dependent with most significant alterations observed between PD1-30 in the CA region and between PD10-30 in the DG region. It was also parameter-dependent with the soma size (except for CA3 pyramids), number of primary dendrites, dendrite diameter, dendritic tortuosity and the branch angle demonstrating little changes, while the total dendritic field area, dendritic length, number of dendritic bifurcations, and spine density being highly increased in all hippocampal regions during the first postnatal month. Moderate ethanol intoxication and the maternal intubation stress during gestation, showed similar, transient effects on the neuron development manifested as a smaller soma size in granule cells, reduced dendritic parameters and lower spine density in pyramidal neurons at PD1. Full recovery from these effects took place within the first 10 postnatal days.ConclusionsThis study showed regional and temporal differences in the development of different morphometric features of principal hippocampal neurons in intact subjects over a protracted 2-months postnatal period. It also demonstrated an overlap in the effects of a moderate fetal ethanol intoxication and a mild maternal stress produced by the intragastric intubation, a commonly used method of ethanol administration to the pregnant dams. Fast recovery from the adverse effects on the soma size, dendritic arborization and spines density observed at birth indicates towards the fetal ethanol/stress induced developmental retardation.     

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。     

Effects of barium, furosemide, ouabaine and 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid (DIDS) on ionophoretically-induced changes in extracellular potassium concentration in hippocampal slices from rats and from patients with epilepsy

Glial cells limit local K(+)-accumulation by K(+)-uptake through different mechanisms, sensitive to Ba(2+), ouabaine, furosemide, or DIDS. Since the relative contribution of these mechanisms has not yet been determined, we studied the effects of bath-applied barium (2 mM), ouabaine (9 microM), furosemide (2 mM), and DIDS (1 mM) on ionophoretically-induced rises in [K(+)](o) in the pyramidal layer of area CA1 from normal rat slices, in the presence of glutamate receptor (Glu-R) antagonists. We also investigated the effect of barium on ionophoretically-induced tetrapropylammonium (TPA(+))-signals in order to test for barium-induced changes of the extracellular space. Finally, we repeated the barium experiment on slices from human non-sclerotic and sclerotic hippocampal specimens to assess a reduced glial capability for barium-sensitive K(+)-uptake in sclerotic tissue from epilepsy patients. In normal rat slices barium augmented ionophoretically-induced rises in [K(+)](o) by approximately 120%, also in the presence of tetrodotoxin (TTX) (by approximately 150%), but did not significantly affect the TPA(+)-signal. Ouabaine also augmented the K(+)-signal, but only by 27%. Furosemide and DIDS had negligible effects. In slices from sclerotic human hippocampus an augmentation of the K(+)-signal by barium was absent. Thus barium augments ionophoretically-induced K(+)-signals to a similar extent as previously shown for stimulus-induced signals. We suggest that glial barium-sensitive K(+)-buffer mechanisms reduce fast local rises of [K(+)](o) by at least 50%. This capability of glial cells is extremely reduced in area CA1 of slices from human sclerotic hippocampal specimens.     

Hypoglycaemic neuropathy in BB/Wor rats treated with insulin implants: electron microscopic observations

Insulin-dependent diabetes mellitus is a chronic metabolic disease that causes long-term secondary complications such as neuropathy. The occurrence of diabetic neuropathy has generally been thought of as being associated with hyperglycaemia. However, in a previous light microscopic examination of plantar nerves in diabetic BB/Wor rats treated with insulin implants we found that eu-/hyperglycaemic rats present a normal picture, whereas eu-/hypoglycaemic rats show severe changes. The aim of the present work is to supplement our previous light microscopic report with electron microsocpic data from the lateral plantar nerve of normal, eu-/hyperglycaemic and eu-/hypoglycaemic BB/Wor rats. Under the electron microscope lateral plantar nerves collected from eu-/hyperglycaemic rats presented a qualitatively normal picture. In addition, the fibre numbers and the size distribution of the myelinated fibres were normal. In contrast, specimens from eu-/hypoglycaemic BB/Wor rats showed severe qualitative changes, interpreted as signs of axonal de- and regeneration. The total number of axons was somewhat subnormal and the sizes of the myelinated fibres were strongly shifted towards smaller diameters. These data confirm our previous light microscopic observations. We conclude that eu-/hypoglycaemic BB/Wor rats treated with insulin implants, but not similarly treated eu-/hyperglycaemic animals, develop a neuropathy in their plantar nerves. Received: 27 November 1997 / Accepted: 12 January 1998     

Differential expression of the estrogen receptors alpha and beta during postnatal development of the rat cerebellum

Estrogen receptor (ER) beta is a dominant ER subtype in the adult cerebellum. However, it is not known if this is also the case for the developing cerebellum. In the present study, quantitative real-time RT-PCR demonstrated that levels of cerebellar ERalpha mRNA in neonatal pups were significantly higher than in adults. In contrast, expression levels of cerebellar ERbeta mRNA remained significantly unchanged during postnatal development. In situ hybridization and immunohistochemistry demonstrated that ERalpha mRNA and protein were predominantly expressed by Purkinje cells at all ages examined. ERalpha-expressing Purkinje cells were confined to the anterior lobes at postnatal day 7 (P7) but distributed in most lobes at P14 and P21. In the adult cerebellum, however, only a few ERalpha-immunoreactive Purkinje cells were observed. Thus, ERalpha expression was transiently increased during the time when Purkinje cell dendritic growth and synapse formation proceed, suggesting that a role for ERalpha in Purkinje cell differentiation. ERbeta expression occurred in Golgi type neurons in the granular layer at P7, Purkinje cells at P14, and basket cells in the molecular layer at P21 and was detected in all the cell types in the adult cerebellum, suggesting a role for ERbeta associated with neuronal differentiation and maintenance. Furthermore, double-labeled immunofluorescence for ERalpha and ERbeta demonstrated their colocalization in Purkinje cells at P14, suggesting a possibility of their interaction. The discrete expression profiles for ERalpha and ERbeta in the developing cerebellum suggest the two ERs play distinct roles in cerebellar development.     

The relationship between hippocampal EEG theta activity and locomotor behaviour in freely moving rats: effects of vigabatrin

The relationship between hippocampal electroencephalogram (EEG) theta activity and locomotor speed in both spontaneous and forced walking conditions was studied in rats after vigabatrin injection (500 mg/kg i.p.). Vigabatrin increased the percentage of time that rats spent being immobile. During spontaneous walking in the open field, the speed of locomotion was increased by vigabatrin, while theta peak frequency was decreased. Vigabatrin also reduced the theta peak frequency during forced (speed controlled) walking. There was only a weak positive correlation (r=0.22) between theta peak frequency and locomotor speed for the saline condition. Furthermore, vigabatrin abolishes the weak relationship between speed of locomotion and theta peak frequency. Vigabatrin and saline did not differ in the slope of the regression line, but showed different offset points at the theta peak frequency axis. Thus, other factors than speed of locomotion seem to be involved in determination of the theta peak frequency.     

脑创伤后NGF对神经干细胞Nestin蛋白表达的影响

目的　研究脑创伤后外源性神经生长因子 (NGF)对神经干细胞Nestin蛋白表达的影响及其意义。方法　建立大鼠流体脑创伤模型 ,采用免疫细胞化学及图像分析等方法 ,观察脑创伤后非NGF处理组和NGF处理组Nestin蛋白表达的变化。结果　成年大鼠Nestin阳性细胞主要位于室管膜下组织 ,细胞的形态主要是胶质细胞。脑创伤后Nestin阳性细胞在室管膜下反应性增加 ,以伤后 7d明显 ,同时在创伤区域周围也可见到大量的Nestin阳性细胞 ,并在伤后 14d继续维持其反应性增加。NGF处理组伤后 7dNestin阳性细胞在伤灶周围更加明显 ,为 2 8.7± 3.8,比同时相点的非NGF处理组明显增加 (P <0 .0 1)。结论　外源性NGF能明显促进脑创伤后Nestin阳性细胞数量的增加 ,增强星形胶质细胞对脑创伤的反应并使其表现有神经干细胞的特征 ,参与神经细胞的再生和重塑。     

In vivo modulatory action of extracellular glutamate on the anticonvulsant effects of hippocampal dopamine and serotonin

PURPOSE: Our recent work (Clinckers et al., J Neurochem 2004;89:834-43) demonstrated that intrahippocampal perfusion of 2 nM dopamine or serotonin via a microdialysis probe offered complete protection against focal pilocarpine-induced limbic seizures and did not influence basal extracellular hippocampal glutamate levels. Ten nanomolar dopamine or serotonin perfusion, however, worsened seizures and was accompanied by significant extracellular glutamate increases to approximately 200%. The significance of these glutamate elevations in seizure generation remains unclear. The present microdialysis study investigated the modulatory role of extracellular hippocampal glutamate levels in these monoaminergic protective and proconvulsant effects. METHODS: A first group of male Wistar albino rats was perfused intrahippocampally for 240 min with 6.25 microM glutamate alone to increase extracellular levels by 200%. Other animals were perfused with anticonvulsant concentrations of monoamines throughout the experiments while receiving continuous coperfusions of 6.25 microM glutamate either before, during, and after (240 min) or only after (100 min) pilocarpine perfusion (40 min). Rats were scored for epileptic behavior, and the mean scores were compared with those of the control group. Microdialysates were analyzed for monoamine and glutamate content with microbore liquid chromatography. RESULTS: No convulsions occurred during glutamate perfusion alone. When monoamines and glutamate were coperfused before pilocarpine administration, the anticonvulsant effect of the monoamines was lost. Glutamate addition after pilocarpine administration did not affect monoaminergic seizure protection. CONCLUSIONS: These results indicate that extracellular glutamate increases per se do not necessarily induce seizures but that they can modulate the anticonvulsant effects exerted by hippocampal monoamines.     

苯甲酸雌二醇对去势(癎)性发作大鼠海马基因表达的影响

目的 分析苯甲酸雌二醇（estradiol benzoate,EB）预处理的去势大鼠经红藻氨酸（kainic acid,KA）诱导痫性发作后海马基因表达的图谱,探讨雌激素对痫性发作大鼠海马的影响.方法 应用含有10 000个基因的cDNA芯片,检测EB干预对KA诱导的去势大鼠痫性发作后海马组织基因表达的影响.应用功能富集分析,筛选有统计学差异的基因功能群.结果 EB逆转了KA致痫后有显著差异表达的基因共392个,其中下调的基因258个（65.82%）,上调的基因134个（34.18%）.经功能富集分析,共筛选出8个主要功能群,其中下调的功能群5个（共21个基因）,主要涉及凋亡、抗凋亡与神经发生、长时程突触传递增强效应等;上调的功能群有3个（共4个基因）,涉及细胞膜受体相关的信号转导等. 结论 EB能逆转KA诱导的去势大鼠痫性发作后海马神经元的基因表达,且可能以促进神经元凋亡为主.