前脑缺血再灌流后大鼠海马NMDA受体亚单位NR2A和NR2B蛋白质表达的变化

用免疫组织化学和图像处理方法 ,观察分析了大鼠前脑缺血 15 min后再灌流 2 h～ 7d的海马结构各区域 NMDA受体亚单位 NR2 A和 NR2 B的表达变化规律及其差异 ,藉以探讨二者在缺血性脑损伤中的作用。结果显示 :( 1) NR2 A在 CA1 区和CA3 区的表达于再灌早期表现为小幅度下降 ( P<0 .0 5 ) ,此趋势在 CA3 区可以逆转 ;但在 CA1 区逐渐加剧 ,第 7d时降至 2 1% ,NR2 A在齿状回的表达几无改变 ;( 2 )与 NR2 A不同 ,再灌后 2 h,NR2 B在 CA1 区的表达即较对照组增高 ( P<0 .0 5 ) ,并持续到再灌后 2 4h,之后转而急剧下降 ,至第 7d仅余 11% ;在 CA3 区及齿状回 ,再灌后 6～ 48h,NR2 B的表达也较对照组增高 ( P<0 .0 5 ) ;在再灌后 72 h则恢复至对照组水平。结果提示 ,缺血性脑损伤后 NR2 A和 NR2 B表达变化的不同可能是造成 CA1 区、CA3区及齿状回缺血敏感性差异的一个重要原因     

短暂性前脑缺血后大鼠海马各区NMDA受体亚单位NR2A和NR2B mRNA的表达变化

应用原位杂交组织化学和图像处理与分析的方法 ,观察短暂性前脑缺血 (15 m in)再灌注 (0 .5 h～ 7d)大鼠海马各区NR2 A和 NR2 B m RNA的表达变化 ,探讨二者在缺血性脑损伤中的作用。结果发现 ,缺血后 ,NR2 A和 NR2 B m RNA在海马各区呈现出一种相对一致的表达。在海马 CA1 区 ,NR2 A和 NR2 B m RNA的表达分别在缺血再灌 6h和 12 h降至低谷 (P<0 .0 5 ) ,然后表达开始回升 ,在缺血再灌 48h都升至高峰 (P<0 .0 5 ) ,之后表达再次下降 ,直至缺血后 7d(P<0 .0 5 ) ;在海马 CA3区 ,二者的表达变化规律与 CA1 区相似 ,不同的是表达变化的幅度明显减小。在齿状回 ,缺血后 0 .5 h～ 72 h,NR2 A和 NR2 B m RNA的表达未见显著性变化 ,72 h后表达开始下降 ,直至缺血后 7d(P<0 .0 5 )。以上结果提示 ,短暂性前脑缺血后 ,NR2 A和 NR2 B m R-NA在大鼠海马各区表达变化的模式不同 ,这种不同可能与海马的选择性易损现象和迟发性细胞死亡有关     

短暂性前脑缺血后大鼠海马各区NMDA受体亚单位1 mRNA的表达变化

目的观察短暂性前脑缺血后大鼠海马各区N-甲基-D-天门冬氨酸受体(NR)1 mRNA的表达变化。方法采用大鼠前脑缺血15min再灌注0．5h～7d动物模型和原位杂交、图像分析等技术。结果缺血后,海马CA1区NR1 mRNA的表达呈明显上升趋势,至24h达高峰;然后表达开始回落,至缺血后7d降至低谷。在CA3区,NR1 mRNA的表达变化与CA1区类似,但变化幅度明显减小。在齿状回,缺血后0．5h～72h,NR1 mRNA的表达未见显著性变化;缺血后7d,表达亦显著降低。结论短暂性前脑缺血后,大鼠海马各区RN1mRNA的表达变化不同,这种不同可能与海马的选择性易损现象和迟发性细胞死亡有关。     

缺血后大鼠海马NR1 mRNA的表达及其与细胞凋亡的关系

目的：研究短暂性前脑缺血后大鼠海马NR1 mRNA的表达及其与细胞凋亡的关系。方法：以四血管阻断法建立脑缺血动物模型,采用原位杂交、TUNEL染色和图像分析等技术。结果：(1)在CA1区和CA3区,NR1 mRNA的表达于缺血后2h上升,24h达高峰,然后下降,但CA3区幅度明显较小;在齿状回,缺血后0．5～72h,表达无显著性变化,缺血后7d才显著降低。(2)TUNEL阳性细胞主要位于CAl区,于缺血后24h出现,至72h达高峰,然后有所减少。结论：大鼠短暂性前脑缺血后,NR1 mRNA的表达和细胞凋亡在海马各区存在显著性差异;提示缺血后NR1 mRNA的表达与海马的选择性易损性和缺血性细胞凋亡之间可能存在着某种联系。     

全脑缺血早期大鼠海马各区域小白蛋白免疫反应阳性中间神经元的不同时相变化的定量分析

近十几年来,缺血性脑损伤的细胞分子机制已成为神经科学界的重要研究内容之一。本实验用免疫组织化学定量分析方法对四管阻塞造成的全脑缺血20min后再灌流0～24h的大鼠海马小白蛋白中间神经元的变化进行了观察。结果显示：再灌流0～6h之间CA2、CA3区小白蛋白阳性中间神经元均出现一过性减少．到24h时恢复三缺血前水平：而CA1区小白蛋白阳性中间神经元的减少出现于再灌流12h后。此外齿状回颗粒层及门区小白蛋白阳性中间神经元变化不显著。本实验结果提示,短暂性全脑缺血早期海马各区域小白蛋白阳性神经元减少的不同时相特征．可能与海马各区域的不同缺血敏感性及不同缺血的病理学表现有关。     

雌激素对全脑缺血再灌小鼠海马CA1区P-CREB和BDNF表达的影响

本文观察了雌激素对全脑缺血再灌的影响并探讨了其作用机制。切除小鼠双侧卵巢同时于颈部皮下植入雌激素(E2)缓释片(OVXE2组)或安慰剂缓释片(OVXPLC组)。术后18d,手术暴露双侧颈总动脉并夹闭25min后再通,制作全脑缺血再灌模型,分别于灌流后1h,12h,3d,7d取材进行PCREB和BDNF免疫组化染色和常规Nissl染色,研究E2对雌性小鼠全脑缺血/再灌流损伤后海马CA1区PCREB和BDNF表达的影响。结果表明:缺血再灌后7d,OVXPLC组海马CA1区神经元排列稀疏,细胞层次减少,细胞数低于OVXE2组(P<0.01);在缺血再灌后3d,OVXPLC组海马CA1区PCREB阳性细胞数低于OVXE2组(P<0.01),而BDNF的表达无统计学差异(P>0.05);在缺血再灌后7d,OVXPLC组PCREB和BDNF的表达均低于OVXE2组(P<0.01)。以上实验结果提示,E2在缺血再灌的中后期可能通过上调海马CA1区PCREB进而促进BDNF的表达,发挥神经元保护作用。     

短暂性前脑缺血再灌流后海马本部与齿状回cGMP反应细胞的差异

观察脑缺血再灌流后海马本部与齿状回 c GMP反应细胞的差异。钳夹沙土鼠的双侧颈总动脉制造脑缺血模型 ,应用免疫荧光组织化学方法。结果表明 :海马本部 c GMP合成增加 ,c GMP主要分布于 CA1 区的放射层及腔隙分子层 ,双重免疫荧光反应证实多数 c GMP阳性细胞是星形胶质细胞。齿状回与海马本部不同 ,较对照组增加了一些中小圆形的 c GMP阳性细胞 ,分布在齿状回各层。本实验结果揭示 ,短暂性前脑缺血再灌流可增加海马本部 c GMP的合成 ,多数 c GMP阳性细胞是星形胶质细胞。意味着星形胶质细胞在脑缺血再灌流早期扮演着重要角色。     

复方丹参对脑缺血再灌注后大鼠海马和齿状回神经细胞凋亡及Bcl-2 mRNA表达的影响

目的:探讨中药复方丹参对大鼠脑缺血再灌注后海马和齿状回神经细胞凋亡及Bcl-2 mRNA表达的影响。方法:采用大脑中动脉内栓线法建立大鼠大脑中动脉缺血再灌注模型,应用原位细胞凋亡检测和原位杂交技术检测大鼠海马和齿状回神经细胞凋亡和Bcl-2 mRNA的表达并做图像分析。结果:与假手术对照组比较,缺血再灌注组凋亡神经细胞主要位于缺血侧海马CA1、CA3区,齿状回凋亡细胞较少。3个区神经细胞Bcl-2mRNA的表达在缺血再灌注2 h后升高,随时间的延长逐渐增强。复方丹参组神经细胞Bcl-2 mRNA的表达明显强于缺血再灌组,而凋亡神经细胞数明显较低。结论:复方丹参可通过上调神经细胞Bcl-2 mRNA的表达,抑制神经细胞凋亡,从而减轻缺血再灌注对大鼠海马和齿状回的损伤。     

NR2B反义寡核苷酸对脑缺血海马CA1区NR2B mRNA表达的影响

为研究NMDA受体2B亚单位(NR2B)反义寡核苷酸(antisense oligonucleotide to NR2B,ANR2B)对短暂性脑缺血后海马CA1区NR2B mRNA表达的影响,分别向成年SD大鼠海马CA1区内立体定位注射ANR2B、NR2B正义寡核苷酸(SNR2B)、无菌生理盐水(NS),或者插针不注射(NSNO),24h后行四动脉阻断前脑缺血手术(缺血15min、再灌注24h),经心冲灌固定取脑,连续冰冻切片,原位杂交组织化学方法染色,光镜下观察各组每侧鼠脑NR2B mRNA的表达变化,并用LEICAQWin进行图像分析。结果显示,单纯缺血组海马各区的NR2B mRNA显色强度明显增加;缺血再灌组、假手术组和正常组海马CA1区内ANR2B注射点及其周围的NR2B mRNA显色明显下降;而在注射SNR2B、NS或NSNO的各组海马切片上,NR2B mRNA显色均无明显变化。结果表明ANR2B可以特异性地在体局部防止缺血后NR2B mRNA的高水平表达。     

NR2B反义寡核苷酸对脑缺血海马CA1区NR2B蛋白质表达的影响

目的：观察前脑缺血后NR2B反义寡核苷酸（ANR2B）对海马CA1区NR2B蛋白质表达的影响,为临床脑血管疾病的防治以及研制特异性新药提供理论基础。方法：正常SD大鼠,脑缺血手术48h前海马CA1区分别立体定位预注射ANR2B、NR2B正义寡核苷酸（SNR2B）。后行四动脉阻断全脑缺血手术,免疫组织化学反应,观察NR2B蛋白质在ANR2B的作用下的表达变化。结果：海马CA1区立体定位注射ANR2B后,注射区及其周围NR2B免疫组织化学染色强度明显下降,仅有少量锥体细胞散在分布。结论：ANR2B可以在体局部抑制缺血早期NR2B亚单位蛋白表达上升趋势。     

脑缺血后大鼠海马一氧化氮合酶表达的变化

用四血管闭塞法造成大鼠一过性全脑缺血。按不同时程，以还原型尼克酰胺腺嘌呤二核苷酸脱氨酶组织化学方法对再灌流期间海马不同亚区内一氧化氮合酶阳性细胞的数量变化进行了研究。结果发现：海马本部的一氧化氮合酶阳性细胞数量在再灌流2～6h即有增高，到12～24h进一步增加至对照水平的3倍左右；3d时已有所减少，7d时在CA1区恢复至对照组的水平。齿状回的一氧化氮合酶阳性细胞数量在再灌流2～6h已有明显的增高，约为对照水平的2倍．并在再灌流12h、24h和3d时保持在同一水平。此外，缺血后各亚区内染出的血管数量于再灌流2～6h即有明显增多，并在再灌流7d后仍明显高于对照组。本文结合文献对缺血性神经元坏死和一氧化氮合酶表达之间的关系进行了讨论。     

Field-specific changes in hippocampal opioid mRNA, peptides, and receptors due to prenatal morphine exposure in adult male rats

Alterations in the opioid system in the hippocampal formation and some of the possible functional consequences were investigated in adult male rats that were prenatally exposed to either saline or morphine (10 mg/kg twice daily on gestational days 11-18). In situ hybridization and Northern blots were used to measure proenkephalin and prodynorphin mRNA, and radioimmunoassays quantified proenkephalin- and prodynorphin-derived peptide levels in the dentate gyrus, CA3, and CA1 subfields of the hippocampal formation. Prenatal morphine exposure in male rats decreases proenkephalin and increases prodynorphin mRNA selectively in the granule cell layer of the dentate gyrus. Similarly, met-enkephalin peptide levels are decreased and dynorphin B peptide levels are increased in the dentate gyrus but not CA3 or CA1 of prenatally morphine-exposed males. In addition, there are decreases in dynorphin-derived peptides in the CA3 subfield. Receptor autoradiography revealed increases in the density of micro but not delta receptor labeling in discrete strata of specific hippocampal subfields in morphine-exposed males. Because alterations in the hippocampal opioid system suggest possible alterations in the excitability of the hippocampal formation, changes in opioid regulation of seizures were examined. Morphine exposure, however, does not alter the latency to onset or number of episodes of wet dog shakes or clonic seizures induced by infusion of 10 nmol [D-Ala2, MePhe4, Gly-ol5]enkephalin into the ventral hippocampal formation. Interestingly, a naloxone (5 mg/kg) injection 30 min before bicuculline administration reverses the increased latency to onset of clonic and tonic-clonic seizures in morphine-exposed males. Thus, the present study suggests that exposure of rats to morphine during early development alters the hippocampal opioid system, suggesting possible consequences for hippocampal-mediated functions.     

Parvalbumin-immunoreactive neurons in the hippocampal formation of Alzheimer''s diseased brain

The number and topographic distribution of immunocytochemically stained parvalbumin interneurons was determined in the hippocampal formation of control and Alzheimer's diseased brain. In control hippocampus, parvalbumin interneurons were aspiny and pleomorphic, with extensive dendritic arbors. In dentate gyrus, parvalbumin cells, as well as a dense plexus of fibers and puncta, were associated with the granule cell layer. A few cells also occupied the molecular layer. In strata oriens and pyramidale of CA1–CA3 subfields, parvalbumin neurons gave rise to dendrites that extended into adjacent strata. Densely stained puncta and beaded fibers occupied stratum pyramidale, with less dense staining in adjacent strata oriens and radiatum. Virtually no parvalbumin profiles were observed in stratum lacunosum-moleculare or the alveus. Numerous polymorphic parvalbumin neurons and a dense plexus of fibers and puncta characterized the deep layer of the subiculum and the lamina principalis externa of the presubiculum. In Alzheimer's diseased hippocampus, there was an approximate 60% decrease in the number of parvalbumin interneurons in the dentate gyrus/CA4 subfield (P<0.01) and subfields CA1–CA2 (P<0.01). In contrast, parvalbumin neurons did not statistically decline in subfields CA3, subiculum or presubiculum in Alzheimer's diseased brains relative to controls. Concurrent staining with Thioflavin-S histochemistry did not reveal degenerative changes within parvalbumin-stained profiles. These findings reveal that parvalbumin interneurons within specific hippocampal subfields are selectively vulnerable in Alzheimer's disease. This vulnerability may be related to their differential connectivity, e.g., those regions connectionally related to the cerebral cortex (dentate gyrus and CA1) are more vulnerable than those regions connectionally related to subcortical loci (subiculum and presubiculum).     

Age-related changes of dopamine receptors in the rat hippocampus: a light microscope autoradiography study

Hippocampus is a brain region involved in learning and memory and is particularly sensitive to ageing. It is supplied with a dopaminergic innervation arising from the midbrain, which is part of the mesolimbic dopaminergic pathway. Dysfunction of the dopaminergic mesolimbic system is probably involved in the pathophysiology of psychosis and behavioural disturbances occurring in the elderly. The present study was designed to assess the density and localisation of dopamine D1- and D2-like receptor subtypes in the hippocampus of male Sprague-Dawley rats aged 3 months (young), 12 months (adult) and 24 months (old). Dopamine D1-like receptors, labelled by [3H]-SCH 23390, in young rats displayed a dentate gyrus-CA1 subfield gradient. The expression was increased in the cell body of dentate gyrus, CA4 and CA3 subfield of old rats compared to younger cohorts, as well as in the neuropil of dentate gyrus. A decreased density of dopamine D1-like receptors was found in the stratum oriens of CA1 and CA3 subfields. Dopamine D2-like receptors, labelled using [3H]-spiperone as radioligand, were expressed rather homogeneously throughout different subfields of the hippocampus. In old rats, the density of dopamine D2-like receptors was decreased in the dentate gyrus, unchanged in the CA4 and CA1 subfields and increased in the CA3 subfield. The above results indicate the occurrence of inhomogeneous changes in the density of dopamine D1- and D2-like receptors in specific portions of hippocampus of old rats. These findings support the hypothesis of an involvement of dopaminergic system in behavioural abnormalities or psychosis occurring in ageing.     

NMDA受体亚单位在海马脑片和在体发育海马结构中表达变化的比较

目的：对比长期培养大鼠海马脑片与在体生后发育海马结构中N-甲基-D-天冬氨酸(NMDA)受体亚单位NR1、NR2A和NR2B表达变化的异同,为利用海马脑片研究NMDA受体亚单位在生理和病理状态中的作用提供资料。方法：免疫组织化学染色、海马脑片培养技术及图像分析。结果：NRI、NR2B在海马脑片各区和生后大鼠海马结构各区表达模式相似,均呈“先升、后降”的趋势,但升降幅度不同;NR2A在海马脑片各区是“先升、后降”的趋势,在生后海马结构各区则呈现“先降后升”的模式。NRI、NR2A、NR2B在脑片和在体发育海马的相似期间,在CA1、CA3、PG区表达均无显著性差异。结论：P3w／C2w时NRI和NR2B在海马脑片各区的表达强度,和其在生后大鼠海马结构中的表达较相似。