大鼠中缝背核一氧化氮合酶神经元投射纤维在大脑皮质微血管的分布

目的：研究通过损毁脑干中缝背核(DR)，探讨中缝背核NOS阳性神经元是否投射分布于大脑皮质微血管。方法：将16只SD雄性成年大鼠分为实验组与对照组。对实验组大鼠中缝背核微量注射喹啉酸，饲养1w，灌注固定，然后将大脑及脑干作冠状冰冻切片，NADPH—d组化染色。结果：实验组大鼠的中缝背核被有效损毁，其NOS阳性神经元的数量减少了59．1％(P＜0．001)。额、顶叶皮质NOS阳性纤维终末减少了32．1％(P＜0．05)，其中附着于皮质微血管的NOS阳性纤维终未了减少了37．8％(P＜0．01)。而枕额叶皮质NOS阳性纤维终末也减少了32．8％(P＜0．05)，其中附着于皮质微血管的阳性纤维终末减少了39．4％(P＜0．01)。结论：位于中缝背核的NOS阳性神经元投射分布于大脑皮质微血管，可能参与大脑皮质血流量的调节。     

局灶性脑缺血大鼠顶叶皮质一氧化氮合酶表达与CT灌注成像

目的:观察重度局灶性脑缺血状态下大鼠顶叶皮质一氧化氮合酶(NOS)表达过程,探讨NOS阳性神经元表达与脑血流量的关系.方法:SD大鼠随机分为5组即正常对照组,假手术组,脑缺血1、6、24 h组.线栓法建立大鼠脑缺血模型,多排螺旋CT灌注成像测量脑血流量,采用还原型尼克酰胺腺嘌呤二核苷酸黄递酶(NADPH-d)法,观察脑血流量低于20%正常值时顶叶皮质NOS表达.结果:与对照组比较,缺血1 h组顶叶皮质NOS阳性神经元数量明显增多;与对照组及缺血1 h组比较,缺血6 h组顶叶皮质NOS阳性神经元数量明显下降;与对照组及缺血1 h组比较,缺血24 h组顶叶皮质NOS阳性神经元数量进一步减少并几乎消失,与脑缺血6 h组比较,无显著差异.当血流量仅轻度下降时,顶叶皮质NOS阳性神经元表达并无明显变化.结论:缺血侧脑血流量低于正常值20%时,顶叶皮质NOS阳性神经元在缺血1 h时显著增加,缺血6、 24 h急剧减少;缺血后NOS阳性神经元表达,不仅与缺血持续时间有关,还与缺血程度有关.     

大鼠海马和颞叶一氧化氮合酶阳性神经元在学习记忆时的表达

目的　对获得空间辨别性学习记忆大鼠的海马结构和颞叶皮质内一氧化氮合酶 (NOS)免疫阳性神经元系统的观察 ,为一氧化氮 (NO)在学习记忆活动中的作用提供形态学依据。方法　以经水迷宫训练获得空间辨别性学习记忆的大鼠为模型组 ,建立游水对照组和空白对照组。用免疫组化的方法观察 3组大鼠海马和颞叶的NOS阳性神经元的形态学特征及测定免疫反应阳性产物的光密度值 (OD )。结果　 (1)NOS阳性神经元在 3组大鼠海马和颞叶呈散在分布。在海马CA1、CA2、CA3、CA4及龄状回 (DG)都有少量分布 ,颞叶以Ⅱ、Ⅲ、Ⅴ、Ⅵ层分布为主。神经元胞体形态有锥体形 ,圆形或椭圆形 ,梭形3种。 (2 )模型组大鼠海马和颞叶皮质NOS阳性神经元较对照组明显增多。 (3)其免疫反应阳性产物的OD值也较对照组明显增大。结论　NOS阳性神经元形态发生了可塑性变化 ,参与了学习记忆     

听源性惊厥点燃诱导新皮质内c-fos和BDNF变化的研究

为探讨前脑结构参与听源性惊厥点燃过程的神经化学机制 ,本研究以 c-fos基因表达作为神经元功能活动的标志 ,采用免疫细胞化学方法 ,对新皮质内参与听源性惊厥点燃过程的神经元的分布状况进行了观察 ,并对相关区域内脑源性神经营养因子表达水平的变化进行了分析。结果显示 ,单次听源性惊厥发作后 ,新皮质内仅有少量散在的 c-fos阳性神经元存在 ;听源性惊厥点燃后 ,额、顶、枕及颞叶皮质内出现大量 c-fos阳性神经元。点燃后额叶及顶叶皮质内脑源性神经营养因子免疫阳性产物的校正光密度值显著增高。结果表明 ,新皮质内大量神经元参与听源性惊厥点燃过程 ,脑源性神经营养因子表达增强很可能是其中的机制之一。     

大鼠端脑内一氧化氮合酶阳性神经元的发育

目的研究大鼠胚胎时期及生后早期一氧化氮合酶（NOS）阳性神经元在端脑的分布,探讨一氧化氮（NO）在脑发育过程中的作用。方法应用还原型尼克酰胺腺嘌呤二核苷酸磷酸脱氢酶（NADPH-d）组织化学方法观察孕14d起至生后14d大鼠端脑内NOS阳性神经元的形态和分布。结果孕14d没有观察到阳性神经元。孕15d纹状体腹外侧已有NOS阳性表达。孕17d在大脑皮质、梨状皮质观察到NOS阳性神经元,但胞体小,树突短,且分支少。随着年龄的增长神经元的胞体数目增多、染色增强或维持一定的水平。到孕20d,NOS阳性神经元分布广泛,梨状皮质、纹状体腹外侧及终纹床核均有大量NOS阳性神经元,其胞体明显增大,树突分支复杂化,长度增加。在生后,除上述脑区的阳性神经元进一步发育分化,大脑皮质和纹状体的NOS阳性纤维相互编织成疏密不等的纤维网外,在胼胝体、海马也观察到NOS阳性神经元。到生后14d,NOS阳性神经元的分布模式总体上已与成年大鼠相似。结论NOS阳性神经元在端脑独特的表达模式提示NO在脑发育和成熟过程中扮演重要角色。     

家兔皮质脊髓束投射神经元的分布

将辣根过氧化物酶（ＨＲＰ）分别注入家兔脊髓单侧颈、胸、腰等不同节段，以显示皮质脊髓束投射神经元的分布。结果表明，大脑皮质的ＨＲＰ标记神经元仅见于颈段注入例，而胸段和腰段注入例未见到皮质标记神经元。标记的皮质脊髓束投射神经元主要分布于注入侧对侧的额叶无颗粒型皮质和顶叶颗粒型皮质，并呈现为３个分隔的标记细胞密集区，分别位于额叶皮质吻侧端的内侧部、邻近前囟的额顶叶皮质、顶叶皮质的外侧部。标记神经元呈柱状     

大鼠孤束核内5-HT能纤维和终末与向臂旁核投射的NOS阳性神经元的联系

应用四甲基罗达明逆行标记和免疫荧光技术相结合 ,在激光扫描共聚焦显微镜下对大鼠孤束核内 5 -HT能纤维和终末与向臂旁核投射的 NOS阳性神经元之间的联系进行了观察。将四甲基罗达明注入一侧外侧臂旁核后可见孤束核尾段背内侧、胶质、小细胞、内侧、中间内侧等亚核和连合亚核内出现较多的逆标神经元 ,四甲基罗达明逆标和 NOS阳性神经元以及 5 -HT阳性终末重叠分布 ,其中四甲基罗达明和 NOS双重阳性神经元分别占四甲基罗达明逆标和 NOS阳性神经元总数的 8.3% ( 14 /16 8)和 18.4% ( 14 /76 )。在此 5 -HT样阳性纤维和终末包绕着 NOS阳性神经元、四甲基罗达明逆标神经元及四甲基罗达明和一氧化氮合酶双重阳性神经元的胞体和树突 ,形成点状紧密接触。本研究结果提示 ,孤束核内来自下行性抑制系统的 5 -HT能纤维和终末可能与向臂旁核投射的 NOS阳性神经元形成突触联系 ,从而可对 NOS阳性神经元所传递的包括伤害性信息在内的内脏感觉传入信息发挥抑制性调控作用     

一氧化氮合酶阳性神经元在小鼠脑内的分布

目的 :研究一氧化氮合酶 (NOS)在小鼠脑内的分布。方法 :用NADPH 黄递酶组织化学技术 ,观察了NOS阳性神经元在小鼠脑内的分布和形态。结果 :在大脑皮质、纹状体、基底前脑、杏仁核、下丘脑和脑干等处有较多一氧化氮合酶阳性神经元的分布。结论 :表明NO与中枢神经系统的诸多功能有关     

大鼠腰骶髓内一氧化氮合酶阳性结构与接受膀胱伤害性刺激神经元的关系

本文应用还原型尼克酰胺腺嘌呤二核苷酸脱氢酶组织化学方法和FOS免疫组化法相结合的双重反应技术，研究了大鼠腰骶髓内的NOS阳性结构的分布及其与膀胱伤害性刺激诱发的FOS表达神经元的关系。结果发现NOS阳性纤维和终末密集分布于后角Ⅰ层和Ⅱ层，其它部位稀少；NOS阳性神经元胞体与膀胱伤害性刺激诱发的c-fos原癌基因蛋白表达的阳性神经元在腰骶髓（L6～S1）分布区域校相似，主要分布于与伤害性信号传递过程密切相关的后角Ⅱ层、中央管周围灰质（包括骶髓后连合核）和中间带外侧核．在此三部位分别有18．7％、11．6％和22．6％和NOS阳性神经元同时呈FOS阳性；有5．56％、2．67％和3％FOS阳性神经元同时是NOS阳性。结合文献和本文结果讨论了NO可能参与脊髓伤害性信号传递和调控的作用．     

大鼠运动皮层投射神经元与Parvalbumin免疫阳性神经纤维终末的关系──免疫荧光、Confocal显微镜观察

Parvalburnin是细胞内一种钙结合蛋白。同时又可作为中枢神经系统内与GABA共存的神经元亚群的特异标记物，主要标记篮状及苔烛细胞。用PAP方谈染色可见大鼠Parvalbumin免疫阳性神经终末在运动皮层锥体神经元胞体周围形成包篮现象，但因该方法的局限性．较难明确二者的关系。为进一步了解Parvalbumin阳性终未在锥体神经元脑体、树突与轴突整体上的分布状况以及运幼皮层内不同传出神经元是否均接受同样的支配，本实验利用FastBlue送行标记、固定脑片细胞内注入LueiferYellow结合免疫荧光、Confocal显微镜观察，研究运动皮层内皮质丘脑（束旁核）、皮质效状体及皮质脊髓三种投射神经元与Parvalbumin阳性终末的关系。通过1．μ连续扫描图像的分析及立体对观察，Parvalbumin阳性终末清晰可见，与LuciferYellow标记的锥体细胞的关系也容易辨别．在三种投射神经元胞体上均可见Parvalbumin阳性终末包绕，形成明显包篮现象，但三种神经元上的终末数未见明显区别·阳性终未还分布于近端树突上，距胞体越远越稀疏：但在距脑体50μm以上的顶树突、30μm以上的基树突及其二、三级分枝的远端树突上仍偶有终末分布．此外，三种神经元轴突起始段上也有少量终末接触，但未形成明显的cartridge现象．这一结果揭示，Parvalb     

The cholinergic innervation develops early and rapidly in the rat cerebral cortex: a quantitative immunocytochemical study.

A recently developed method for determining the length of cholinergic axons and number of cholinergic axon varicosities (terminals) in brain sections immunostained for choline acetyltransferase was used to estimate the areal and laminar densities of the cholinergic innervation in rat frontal (motor), parietal (somatosensory) and occipital (visual) cortex at different postnatal ages. This cortical innervation showed an early beginning, a few immunostained fibers being already present in the cortical subplate at birth. In the first two postnatal weeks, it developed rapidly along three parameters: a progressive increase in the number of varicosities per unit length of axon, and a lengthening and branching of the axons. Between postnatal days 4 and 16, the number of varicosities increased steadily from two to four per 10 microm of cholinergic axon. The mean densities of cholinergic axons increased from 1.4 to 9.6, 1.7 to 9.3 and 0.7 to 7.2 m/mm(3), and the corresponding densities of varicosities from 0.4 to 3.9, 0.4 to 3.5, and 0.2 to 2.6x10(6)/mm(3) in the frontal, parietal and occipital areas, respectively. The rate of growth was maximal during these first two weeks, after which the laminar pattern characteristic of each area appeared to be established. Adult values were almost reached by postnatal day 16 in the parietal cortex, but maturation proceeded further in the frontal and particularly in the occipital cortex.These quantitative data on the ingrowth and maturation of the cholinergic innervation in postnatal rat cerebral cortex substantiate a role for acetylcholine in the development of this brain region and emphasize the striking growth capacity of individual cholinergic neurons.     

Distribution of the cells of origin of the corpus callosum and anterior commissure in the marmoset monkey

Summary The neurons of origin of the great cerebral commissures of the marmoset monkey were identified by horseradish peroxidase histochemistry and their distribution was studied. Six adult marmosets were used. Three were normal: the others were subjected to section of the corpus callosum (CC), sparing the anterior commissure (AC). All six were injected with horseradish peroxidase throughout one cerebral hemisphere. The three normals provide information on the origins of both the CC and AC, whereas the three callosotomized monkeys allow study of the origins of the AC alone. All CC and AC neurons in the marmoset are pyramidal cells. Except for layer I, all cortical layers possess commissural cells; their laminar organization varies according to cortical area. There exists a progression in predominance from supra- to infragranular commissural neurons proceeding from temporal through occipital to parietal and finally to frontal cortex. Major acallosal zones are found in the primary visual cortex and the fore- and hindlimb representations of the somatosensory cortex. Correlations between commissural neuron distribution and cytoarchitectonic areas are not always obvious. Commissural neurons were not organized in columnar fashion.     

The mode of projections of single locus coeruleus neurons to the cerebral cortex in rats

Axonal distributions of single locus coeruleus neurons within the cerebral cortex were examined with antidromic stimulation technique combined with cortical lesions (frontal lobotomy and lobectomy). In urethan-anesthetized rats, stimulating electrodes were implanted in 10 points extending over nearly the entire cerebral cortex, and antidromic responses of single locus coeruleus neurons to stimulation of these stimulus sites were analysed. Fifty percent of locus coeruleus neurons examined were activated antidromically from at least one cortical point in the cerebral cortex. The pattern and extent of axonal distributions of single locus coeruleus neurons in the cortex appeared to vary from cell to cell. From the results obtained in rats with the cortical lesions, it is concluded that in addition to locus coeruleus neurons with intracortical axons running from rostral to caudal, there are the neurons projecting to the occipital cortex without innervating the frontal cortex and those projecting simultaneously to the frontal and occipital cortex with two axonal branches. There was no topographic order between the recording sites within the locus coeruleus and the projection sites in the cortex.     

Isolated catecholaminergic projections from substantia nigra and locus coeruleus to caudate,hippocampus and cerebral cortex formed by intraocular sequential double brain grafts

Summary Sequential intraocular grafting of defined areas from fetal rat brain to adult host rats was used to explore the possibility that such double grafts would become interconnected. Norepinephrine- containing neurons of the locus coeruleus were grafted together with either parietal cerebral cortex, hippocampus, or the caudate nucleus. Dopamine-containing neurons of the substantia nigra were transplanted together with either parietal cerebral cortex or the caudate nucleus. The brainstem grafts showed good survival and development in oculo, using both histochemical and electrophysiological criteria. Locus coeruleus neurons were found to innervate cerebral cortex, hippocampus, and the caudate nucleus. Substantia nigra neurons invaded cerebral cortex abundantly, with a terminal distribution typical of cortical DA terminals in situ. The innervation of the caudate nucleus from substantia nigra transplants was variable, but areas of dense confluent terminals were observed.We conclude that sequential brain grafting in oculo permits generation of isolated yet defined catecholaminergic projections, which are suitable for electrophysiological, pharmacological, and histochemical studies.     

Control of cerebral cortical blood flow by stimulation of basal forebrain cholinergic areas in mice

We examined whether activity of the nucleus basalis of Meynert (NBM) regulates regional cerebral cortical blood flow (rCBF) in mice, using laser speckle and laser Doppler flowmetry. In anesthetized mice, unilateral focal stimulation, either electrical or chemical, of the NBM increased rCBF of the ipsilateral cerebral cortex in the frontal, parietal and occipital lobes, independent of changes in systemic blood pressure. Most of vasodilative responses to low intensity stimuli (2 times threshold intensity: 2T) were abolished by atropine (a muscarinic cholinergic blocker), whereas responses to higher intensity stimuli (3T) were abolished by atropine and mecamylamine (a nicotinic cholinergic blocker). Blood flow changes were largest when the tip of the electrode was located within the area containing cholinergic neurons shown by choline acetyltransferase-immunocytochemistry. These results suggest that cholinergic projections from basal forebrain neurons in mice cause vasodilation in the ipsilateral cerebral cortex by a combination of muscarinic and nicotinic mechanisms, as previously found in rats and cats.     

Efferent connections of the nucleus reuniens and the rhomboid nucleus in the rat: an anterograde PHA-L tracing study

Direct projections from the nucleus reuniens (Re) and the rhomboid nucleus (Rh) in the midline of the thalamus were examined in the rat by utilizing anterograde axonal transport of Phaseolus vulgaris leukoagglutinin (PHA-L). The Re projected axon terminals densely to the anterior cingulate cortex, infralimbic area of the medial frontal cortex, agranular insular cortex, entorhinal cortex, and parasubiculum. Labeled terminals in these cerebral cortices were distributed mainly in layer I, except for the entorhinal cortex where labeled terminals were distributed in layers I-IV. On the other hand, labeled terminals of projection fibers from the Rh to the cerebral cortex were distributed in layers II-VI of the anterior cingulate cortex, frontal cortex, parietal cortex, and agranular insular cortex. In the nucleus accumbens, caudate putamen, and basolateral amygdaloid nucleus, labeled terminals from the Rh were more dense than those from the Re. In the hypothalamus, labeled terminals from the Re were more dense than those from the Rh. The septal nuclei and field CA1 of Ammon's horn received labeled axon terminals from the rostral portion of the Re, but not from the caudal portion of the Re or the Rh. The patterns of distribution of axon terminals from the Re and Rh were similar in other subcortical target regions. To confirm the PHA-L results, wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) was injected into two projection sites of PHA-L-labeled axons. After injection into the agranular insular cortex, WGA-HRP-labeled neurons were found in the Re, but only a few were present in the Rh. In contrast to this, after WGA-HRP injection into the nucleus accumbens, WGA-HRP-labeled neurons were found in the Rh, but only a few were seen in the Re.     

大鼠大脑皮层－尾壳核和尾壳核－黑质间的往返定位投射

用霍乱毒素Ｂ亚单位（ＣＢ）追踪法系统地研究了大鼠大脑皮层与尾壳核和尾壳核与黑质之间的定位投射。将ＣＢ分别泳入尾壳核不同节段的不同区域后，大脑皮层内的逆标胞体和顺标终末主要见于额叶１区和２区、顶叶１区和２区以及颗粒岛皮质；黑质内的顺标终末主要见于网状带的不同部位，而逆标胞体则主要见于致密带和腹侧被盖区。本研究结果说明在大鼠大脑皮层－尾壳核和尾壳核－黑质之间存在着且有点对点定位特征的往返联系。这种定位投射对躯体运动的精细调节提供了形态学基础。     

Tyrosine hydroxylase-immunoreactive intrinsic neurons in the rat cerebral cortex

Summary Using specific antisera against the catecholamine synthesizing enzyme, tyrosine hydroxylase (TH), in combination with the peroxidase-antiperoxidase method and/or the avidin-biotin complex method, we have found a new group of TH immunoreactive (TH-I) neurons in the rat cerebral cortex. Numerous TH-I cells were observed all over the isocortex, that is, frontal, temporal, parietal and occipital regions, and in some parts of the allocortex such as the anterior cingulate cortex, the retrosplenial cortex and anterior part of the insular cortex. In contrast, they were rare in the perirhinal cortex, posterior part of the insular cortex, piriform cortex, entorhinal cortex and hippocampal formation. TH-I cells were situated throughout all cortical layers, but were most concentrated in layer II/III. Although TH-I cells were heterogeneous in shape, the majority were bipolar. All TH-I cells so far examined appeared to be of the nonpyramidal type. The majority of these intrinsic TH-I neurons also contained the GABA-like immunoreactivity and thus could be regarded as a subpopulation of cortical GABAergic neurons.