出生前人脑海马结构含GABA神经元的分布和发育

本实验采用免疫细胞化学方法研究了１４～３８ 周人胎海马结构含ＧＡＢＡ 神经元的分布和发育。主要结果有：（１）早在１４周时便有许多含ＧＡＢＡ 神经元分布于海马和齿状回各部；（２）１４～２２ 周海马脑室带和中间带含ＧＡＢＡ 神经元的密度逐渐减少，２２ 周及以后这两部位仅见少量含ＧＡＢＡ 神经元，其它层含ＧＡＢＡ 神经元的密度在出生前发育过程中呈现先逐渐减少，后逐渐增加，最后又下降的规律；（３）在各发育阶段，含ＧＡＢＡ 神经元主要分布于海马的锥体层、始层以及齿状回的多形层和门区，而含ＧＡＢＡ 神经元的密度由ＣＡ１ 区向ＣＡ３ 区逐渐降低；（４）许多含ＧＡＢＡ 纤维出现于１４～２２ 周海马分子腔隙层及１８～３８ 周海马始层；（５）在各发育阶段，海马伞内可见许多含ＧＡＢＡ 纤维和少量含ＧＡＢＡ 神经元。以上结果提示：人类海马结构在胚胎时期含ＧＡＢＡ 神经元的出现和分化较早，且在发育过程中至少部分含ＧＡＢＡ 神经元和纤维的存在是暂时性的；至少部分传出纤维含有ＧＡＢＡ。     

大鼠海马结构中兴奋性氨基酸神经元的发育

目的：研究胚胎时期大鼠海马结构中谷氨酸和门冬氨酸神经元的分布及发育规律。方法：用免疫组化ＡＢＣ方法，对Ｅ１４，Ｅ１６，Ｅ１８、Ｅ２２天大鼠胚胎海马结构中谷氨酸和门冬氨酸神经元的发育情况进行观察。结果：Ｅ１４天，在海马神经上皮内谷氨酸和门冬氨酸能前体细胞散在分布；Ｅ１６天，随着丛状层的出现，成熟的谷氨酸和门冬氨酸神经元迁入其内；Ｅ１８天，阿蒙角神经上皮增厚，阳性前体细胞增多，ＣＡ１锥体层刚出现即分布     

人胎海马结构小白蛋白免疫反应性神经元的分布

目的 观察人胎海马结构小白蛋白（PV）免疫反应性神经元的分布。方法 取孕龄为30周的人胎尸体,用ABC免疫细胞化学方法显示PV免疫反应性神经元。结果 海马结构的各区域内均有丰富的PV免疫反应性神经元分布,以锥体细胞怪最为密集。CA1、CA2、CA3始层PV免疫反应性神经元呈散在分布,胞体形态多样,细胞的突起伸向浅怪的始层和深层的分子层;分子层PV免疫反应性神经元较稀少。门区PV免疫反应性神经元分布密集,但细胞分层不明显,可见部分细胞的突起伸向齿状回;齿状回PV免疫反应性神经元集中分布于颗粒细胞层,其余各层在有少量散在PV免疫反应性神经元,细胞染色浅谈,无明显突起,下托复合体PV免疫反应性神经元主要分布于锥体细胞层,始层和分子层较稀少,细胞淡染,突起不明显。结论 海马结构的各区域均有丰富的PV免疫反应性神经元分布,主要分布于锥体细胞层和齿状回的颗粒层。各区域PV免疫反应性神经元发育成熟的时间可能并不同步,CA1－3和门区PV免疫反应性神经元发育成熟早于齿状回和下托复合体。     

大鼠脊髓和后根节内5—HT1A,2A受体mRNA阳性神经元的分布

目的 观察大鼠脊髓及后根节内５－ＨＴ１Ａ,２Ａ受体ｍＲＮＡ阳性神经元的分布。方法 原位杂交组织化学技术。结果 （１）５－ＨＴ１Ａ受体ｍＲＮＡ阳性神经元分布于脊髓灰质各层,主要见于一角浅层（Ⅰ、Ⅱ层）及Ⅲ、Ⅳ层,Ⅴ、Ⅶ层和Ｘ层也有散在分布。在角（Ⅸ层）内仅有小量阳性神经元;（５）５－ＨＴ２Ａ受体ｍＲＮＡ阳性神经元的分布较局限,主要见于后角浅层及前角（Ⅸ层）神经元,在其他各层仅呈散在分布。在大鼠后根节内观察到：（１）１０．４％的后根节细胞呈５－ＨＴ１Ａ受体ｍＲＮＡ阳性,阳性细胞以中、小型节细胞为主;（２）１７．４％的后根节细胞呈５－ＨＴ２Ａ受体ｍＲＮＡ阳性,阳性细胞也以中、小型节细胞为主。结论 ５－ＨＴ１Ａ和５－ＨＴ２Ａ受体在脊髓和后根节内具有不同的分布特点,它们在介导５－羟色胺在脊髓水平的镇痛及在外周的致痛作用中     

人类初级视皮质含Parvalbumin神经元的出生前发育

用免疫细胞化学方法研究了１９～４０周人胎初级视皮质含Ｐａｒｖａｌｂｕｍｉｎ（ＰＶ）神经元及纤维的发育和形态。１９周，少数含ＰＶ神经元出现于皮质板深部（相当于Ⅵ层处）。２４周，含ＰＶ神经元仍仅见于Ⅵ层，但数量明显增加，多为双极细胞。２６～２９周，许多含ＰＶ神经元可见于Ⅵ及Ⅴ层，双级、多级及双簇细胞均可见。３３～４０周，Ⅴ、Ⅵ层含ＰＶ神经元数目逐渐增加，并随胎龄增大依次出现于Ⅳ、Ⅲ和Ⅱ层，多为多极及双簇细胞。这些结果提示，Ⅱ－Ⅵ层含ＰＶ神经元遵循从深至浅的发育规律。另外，２９～４０周皮质Ⅰ层一些Ｃａｊａｌ－Ｒｅｔｚｉｕｓ神经元和水平纤维亦含ＰＶ；３８～４０周皮质Ⅰ层深部还可见较多含ＰＶ的小型神经元，散在分布于Ⅰ层含ＰＶ的水平纤维之间，提示ＰＶ可能参与发育过程中Ⅰ层内各种神经成分间的相互作用。     

妊娠中期胎儿海马结构发育的7.0T MRI研究

目的:探讨妊娠中三个月内海马结构发育的形态变化以及其折叠角的变化,分析其发育规律.方法:收集胎儿标本51例,孕龄为14～22周,经超声筛选,排除神经系统异常.用德国产BRUKER 7.0T MR扫描,在二维图像上利用eFilm软件进行形态变化观察.定义海马折叠角(HIA)为海马角外缘和海马下托内上缘的连线与通过中线结构的直线的夹角,并在经过脑桥的冠状面上对此角进行测量.结果:13～14周时,海马结构几乎没有折叠,其皮层有3层结构,即室周层、中间带和皮质板;15～17周时,齿状回和海马角开始向颞叶内部折叠,海马结构典型特征是表现出明显的板层结构,CA2和CA3区的皮层逐渐变窄,海马结构的边缘层逐渐变厚;18～22周时,齿状回和海马角折叠进入颞叶,形成C型,海马板层结构变窄.随着孕龄增加,左右两侧HIA线性增大,未发现左右两侧HIA存在性别与半球间差异.结论:7.0T MRI能够清晰显示妊娠中期海马结构的发育变化,并可获得准确的HIA变化数据,这些数据对评价宫内或生后海马结构发育相关疾病有参考意义.     

龟龄集对大鼠海马结构内神经丝蛋白表达的影响

目的:研究龟龄集对大鼠海马结构内神经丝蛋白的影响,探索龟龄集的抗衰老功效。方法:免疫组织化学法。结果:在海马结构内并不是所有的神经元均可被神经丝蛋白所标记。喂药鼠海马结构内神经丝蛋白标记的胞体和纤维均明显多于对照鼠。结论:并非海马结构所有神经元内或同一神经元的不同部位均存在神经丝蛋白。龟龄集具有延缓海马结构神经元衰老,维持神经元神经丝蛋白的合成功能,可借以改善学习记忆功能。     

人胎初级视皮质含Calbindin神经元的发育

本文采用免疫细胞化学方法研究了16～38周人胎儿初级树皮质含Calbindin神经元的发育．16周时,含Calbindin神经元主要分布于脑室带、脑室下带和中间带深部,其他皮质带散在存在。脑室带和脑室下带的细胞大多跑体较大,胞浆和胞核均含阳性产物,而其它皮质带细胞胞核常不染色。19周时,脑室带和脑室下带的含Cal－bindin神经元明显减少,仅存在极少量,其它皮质带含Calbindin神经元的状况类似16周。21周时大多数含Cal－bindin神经元位于Ⅴ、Ⅵ层。以后,随着服龄增大,较多的含Calbindin神经元逐渐依次出现于Ⅳ、Ⅲ和Ⅱ层,遵循皮质神经元从深至浅的发育规律。这些神经元的形态也由以双极细胞为主发育成以多极细胞为主,染色逐渐加深,突起逐渐增长。在19～28周,皮质Ⅰ层的一些Cajal-Retzius细胞和水平纤维亦表达Calbindin。本实验中较多的含Calbindin神经元于发育早期在皮质增殖带的出现,提示Calbindin在皮质的早期发育过程中可能发挥重要作用。     

出生后大鼠海马结构兴奋性氨基酸神经元的发育

用免疫组化方法结合体视学研究,对出生后雄性大鼠海马结构中谷氨酸和门冬氨酸神经元的发育状况进行了定性与定量观察。结果证明：谷氨酸和门冬氨酸神经元主要分布于锥体层和颗粒层,其他各层相对稀少。颗粒层中两者的平均灰度值都高于锥体层（Ｐ＜ ０．０５）。锥体层中两种神经元的数密度、面数密度和体密度在发育过程中逐渐下降,平均体积逐渐增大,至生后２１ｄ 趋于稳定。颗粒层中上述参数变化不大,但随着细胞层次的增多,两种神经元的总数不断增长。谷氨酸和门冬氨酸神经元的体视学参数排列顺序如下：密度参数为颗粒层＞ ＣＡ１＞ ＣＡ３＞ ＣＡ４ 锥体层,平均体积为ＣＡ３＞ ＣＡ４＞ ＣＡ１ 锥体层＞ 颗粒层。在细胞总数中（尼氏染色标本计算）,ＣＡ１、ＣＡ３、ＣＡ４ 锥体层和颗粒层中谷氨酸神经元分别占７２．７９％ 、７４．５６％ 、６９．８３％ 、７３．５７％ ;门冬氨酸神经元分别占６９．２３％ 、７１．４４％ 、６８．１３％ 、６７．９６％ ,两者相比存在显著性差异（Ｐ＜ ０．０５）,即各亚区中谷氨酸神经元均多于门冬氨酸神经元。     

大鼠海结构在空间辨别性学习记忆时突触表达的变化

目的：探讨空间辨别性学习记忆活动与突触可塑性的关系。方法：用免疫组织化学方法对具有空间辨别性学习记忆功能的模型大鼠与对照组大鼠海马结构内毒素１的表达进行对比研究。结果：（１）对照组大鼠海马结构现俨未见明显的突触素颗粒产物,在模型组,经水迷宫训练１周的大鼠海马切片上见到齿状回、ＣＡ４和ＣＡ３区出现深染的颗粒分布,ＣＡ２和ＣＡ１区颗粒较少,训练２周的大鼠海马结构内的染色显示颗粒与训练１周的比较无明显差     

Calbindin-D28k在出生前人海马本部及下托神经元的表达及其变化

本实验采用免疫组织化学方法研究了１３～３８ 周人胎儿海马本部及下托含Ｃａｌｂｉｎｄｉｎ－Ｄ２８ｋ 神经元的分布和发育。结果表明：在１３～１４ 周时,许多含Ｃａｌｂｉｎｄｉｎ－Ｄ２８ｋ 锥体细胞可见于ＣＡ１ 区锥体细胞层中部及深部,随着胎龄增大,ＣＡ１ 区含Ｃａｌ－ｂｉｎｄｉｎ－Ｄ２８ｋ 锥体细胞的数量及密度逐渐下降,最终消失,并且这种下降及消失首先从含Ｃａｌｂｉｎｄｉｎ－Ｄ２８ｋ 锥体细胞区浅部开始,然后向深部推进;在１３～２８ 周期间,ＣＡ２ 和ＣＡ３ 区也有许多含Ｃａｌｂｉｎｄｉｎ－Ｄ２８ｋ 锥体细胞,但至３２ 周以及其后,ＣＡ３ 和ＣＡ２ 区则不见含Ｃａｌｂｉｎｄｉｎ－Ｄ２８ｋ 锥体细胞,仅在ＣＡ２ 与ＣＡ１ 交界区见到少量弱染的含Ｃａｌｂｉｎｄｉｎ－Ｄ２８ｋ 锥体细胞。此外,在２８～３８ 周期间,ＣＡ３ 和ＣＡ２ 区锥体细胞层周围可见许多含Ｃａｌｂｉｎｄｉｎ－Ｄ２８ｋ 的苔藓纤维,其密度随胎龄增大而增加。１４～３８ 周期间,许多含Ｃａｌｂｉｎｄｉｎ－Ｄ２８ｋ 的锥体细胞也出现于下托锥体细胞层全层及前下托锥体细胞层浅部（细胞岛区）及中部。这些区域含Ｃａｌ－ｂｉｎｄｉｎ－Ｄ２８ｋ 锥体细胞的数量及染色强度在１４～２４ 周期间逐渐增     

Histological,histochemical, and immunohistochemical studies of hippocampus in male New Zealand rabbits

The present study aims to give detailed histomorphological features of the hippocampus of adult male New Zealand rabbits. Both histological and histochemical specimens were prepared to be examined microscopically by using a light microscope. The hippocampus appeared as C-shaped hippocampal proper, dentate gyrus, and subiculum. The hippocampal proper subdivided along its length according to the density and size of its major constituent pyramidal cells into four distinct regions named Cornu Ammonis (CA1, CA2, CA3, and CA4). With the histochemical preparations, each of these regions consisted of five layers, stratum alveolus, stratum oriens, stratum pyramidale, stratum radiatum, and stratum lacunosum-moleculare. The stratum pyramidale constituted the middle dark zone and contained the principal excitatory neurons and a few interneurons. Histochemically, the pyramidal neurons along all regions of the CA reacted positively to Grimelius silver impregnation, lead hematoxylin, Gomori's aldehyde fuchsin, aldehyde thionine, Gomori's chrome alum hematoxylin, and performic acid alcian blue stains. Immunohistochemically, the pyramidal neurons reacted positively to anti-NSE antibodies. The dentate gyrus was formed of three distinct layers. The subiculum was formed of proper subiculum, presubiculum, and parasubiculum.     

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).     

GABAergic neurons containing somatostatin-like immunoreactivity in the rat hippocampus and dentate gyrus

Summary The distribution of somatostatin-like immunoreactive (SS-LI) material and its colocalization with glutamic acid decarboxylase (GAD)-like immunoreactivity were studied in the rat hippocampus and dentate gyrus neurons using immunohistochemistry. In the dentate gyrus and CA1 region, SS-LI perikarya were concentrated in the hilus and in the stratum oriens, respectively, whereas immunoreactive cell bodies were rarely seen in other layers. Approximately half of the SS-LI neurons of the CA3 region were situated in the stratum oriens, the other half being scattered in strata pyramidale, lucidum and radiatum. About 90% of SS-LI neurons were also GAD-like immunoreactive, whereas about 14% of GAD-like immunoreactive (GAD-LI) neurons were SS-like immunoreactive. The percentage of GAD-LI neurons which were also immunoreactive for SS varied from one layer to the other. This percentage was about 30% in the hilus of the dentate gyrus and in the stratum oriens of the CA1 and CA3 regions; it was 5–10% in the strata pyramidale, lucidum and radiatum of the CA3 region and reached only 2% in the granule cell layer and molecular layer of the dentate gyrus and in the stratum pyramidale and stratum radiatum in the CA1 region. These observations indicate that the majority of SS-LI neurons in the rat hippocampal formation are a subpopulation of GABAergic neurons.     

Inhibition of the canonical Wnt pathway by Dickkopf-1 contributes to the neurodegeneration in 6-OHDA-lesioned rats

We investigated the cellular localization and progressive changes of corticotropin releasing factor (CRF) in the mouse hippocampus, during and after pilocarpine induced status epilepticus (PISE) and subsequent epileptogenesis. We found that CRF gene expression was up-regulated significantly at 2h during and 1d after PISE in comparison to control mice. Immunohistochemical analysis showed that the number of CRF and Fos immunoreactive cells was increased significantly in the strata oriens and pyramidale of CA1 area and in the stratum pyramidale of CA3 area at 2h during and 1d after PISE. CRF was induced in calbindin (CB) or calretinin (CR) immunoreactive interneurons in stratum oriens at 2h during PISE. It suggests that induced CRF may be related to the over excitation of hippocampal neurons and occurrence of status epilepticus. It may also cause excitoneurotoxicity and delayed loss of CA3 and CA1 pyramidal neurons, leading to the onset of epilepsy.     

Ontogeny of enkephalin-like immunoreactivity in the rat hippocampus

The postnatal development of leucine5-enkephalin-like immunoreactivity within the hippocampal formation of the rat has been analyzed using immunocytochemical techniques. From the day of birth to postnatal day three, no intrinsic hippocampal elements exhibit immunoreactivity although labeled axons are found within the fimbria, within the alveus, and in the vicinity of the angular bundle. On postnatal day 4, a few immunoreactive hippocampal neurons can be seen in stratum radiatum of the region CA3 and by postnatal day 8, within the hilus, strata pyramidale and oriens of regio superior, and the subiculum. There is a dramatic increase in the incidence of immunoreactive perikarya between postnatal days 8 and 10 in all fields as well as the appearance of labeled neurons in CA1 stratum pyramidale and stratum granulosum of the dentate gyrus. Two days after the first appearance of immunoreactive perikarya, intensely immunoreactive neurons, labeled much more extensively than is ever seen in the adult, are encountered in each subfield of the hippocampus. The spatio-temporal order in both the emergence of perikaryal immunoreactivity and the transient appearance of intensely immunoreactive neurons follows that of neurogenesis, with immunoreactivity developing 12-14 days after the peak period of last cell division for a given hippocampal region. The incidence of immunoreactive perikarya in the dentate gyrus was quantified in rat pups ranging from postnatal days 8 to 19. The appearance of labeled neurons followed the spatio-temporal gradients that have been described for neurogenesis in this region as well. Immunoreactive perikarya emerged in the suprapyramidal stratum granulosum prior to their emergence in the infrapyramidal zone and in the temporal pole of the dentate earlier than in the mid-dorsoventral dentate. The lateral perforant path and mossy fiber axons, seen to exhibit enkephalin-like immunoreactivity in the adult hippocampal formation, differ in their relative maturity at the age immunoreactivity first appears. Immunoreactivity appears as early as postnatal day 4 in the lateral perforant path, an age at which these axons are just growing into their target field while it is not found within the mossy fibers until after postnatal day 10, an age at which mossy fiber bouton elaboration is well advanced and physiologically competent mossy fiber synapses with the regio inferior pyramidal cells have been established. The latter observation indicates that enkephalin is not necessary for synaptic transmission at the mossy fiber synapse.     

Non-pyramidal hippocampal projection neurons: A light and electron microscopic study

Summary Following injections of horseradish peroxidase conjugated with wheat germ agglutinin into the medial nucleus accumbens of the rat, a large number of projecting pyramidal neurons in the hippocampus were retrogradely labelled. In addition to this major projection, a few retrogradely labelled cells were tentatively identified at the light microscopic level as non-pyramidal neurons. These presumptive non-pyramidal neurons were found in all hippocampal layers, although they were mainly outside the stratum pyramidale, in the stratum oriens. Ultrastructurally, in serial sections, the non-pyramidal nature of 20 of these neurons was confirmed by their characteristic features such as deeply indented nuclei, occasional intranuclear inclusions, and symmetric and asymmetric synaptic contacts with their somata. Possible-transmitters used by these neurons are discussed.     

Nitric oxide-containing pyramidal neurons of the subiculum innervate the CA1 area

Neurons and axon terminals containing neuron-specific nitric oxide synthase (nNOS) were examined in the rat subiculum and CA1 area of Ammon's horn. In the subiculum, a large subpopulation of the pyramidal neurons and non-pyramidal cells are immunoreactive for nNOS, whereas in the neighbouring CA1 area of Ammon's horn only non-pyramidal neurons are labelled with the antibody against nNOS. In the pyramidal layer of the subiculum, nNOS-positive axon terminals form both asymmetric and symmetric synapses. In the adjacent CA1 area the nNOS-positive terminals that form symmetric synapses are found in all layers, whereas those terminals that form asymmetric synapses are only in strata radiatum and oriens, but not in stratum lacunosum-moleculare. In both the subiculum and CA1 area, labelled terminals make symmetric synapses only on dendritic shafts, whereas asymmetric synapses are exclusively on dendritic spines. Previous observations demonstrated that all nNOS-positive non-pyramidal cells are GABAergic local circuit neurons, which form exclusively symmetric synapses. We suggest that nNOS-immunoreactive pyramidal cells of the subiculum may innervate neighbouring subicular pyramidal cells and, to a smaller extent, pyramidal cells of the adjacent CA1 area, forming a backward projection between the subicular and hippocampal principal neurons. Electronic Publication