中华大蟾蜍脊髓灰质神经元构筑和脊神经的研究

本实验对中华大蟾蜍（Bufo bufo gargarizans）脊髓灰质神经细胞构筑、脊髓节段与椎骨的对应关系、脊神经出椎管的部位等进行了初步研究．方法：动物麻醉致死，灌流固定，解剖观察，冰冻切片，中性红染色，光镜观察．结果：①脊髓灰质腹角由大、中、小三种多突起神经元构成．其神经元胞体的直径分别为20μm、11μm和8μm左右；不同脊髓节段中腹角的神经元构成数量和类型不同．脊髓灰质的背角神经元胞体直径多在8μm左右；不同脊髓节段的背角神经元构成在形态和数量上也不同．在2～6脊髓节段偶见中间带神经元，其胞体直径在7μm左右．②对脊髓节段的长度、脊髓节段与椎骨的对应关系、脊神经出椎管的部位及形态、脊神经的背根和腹根的粗细进行了观察．结论：中华大蟾蜍脊神经形态和脊髓灰质神经细胞构筑与其功能密切相关．     

人胚胎脊髓P物质和脑啡肽的免疫细胞化学研究

用PAP法研究人胚胎脊髓SP和ENK的分布和发育,收集死亡人胚胎37例,胚龄(受精龄)最小5周,胎龄最大40周。结果最早于第5周在原始脊髓翼板(alar lamina)的后份发现两种肽;灰质前角和灰质中间带最早见于第10周;缘层(marginal layar)白质前外侧索两种免疫反应首先可见于第6周;而后外侧索两种不同肽的最早出现,时间稍有差异,SP样反应见于第5周,ENK样反应则见于第6周。     

小鼠脊髓颈段一氧化氮合酶阳性神经元的分布研究

用NADPH-黄递酶组织化学方法观察小鼠脊髓颈段一氧化氮合酶阳性神经元(Nitric oxide synthase,NOS)的分布,结果显示在颈髓胶状质和中央管周围灰质内有较多一氧化氮合酶神经元分布,在前角基部内侧有较大的NOS神经元.后角浅层和中间带分别含有密集和中度密集的一氧化氮阳性纤维;在颈髓的前索白质和后索白质中也有一氧化氮合酶阳性神经元的分布,NOS阳性神经元的纤维较细,有串珠状膨大,相互交织成疏密不等的网络.这些神经元大多显示Golgi染色外观,它们尚不能与任何已知的神经递质类型神经元单一对应.     

初孵扬子鳄中脑视叶组织学结构观察

用光镜对扬子鳄中脑视叶的组织学结构进行了研究.从背侧到腹侧,扬子鳄中脑视叶可分顶盖和被盖两部分,二者之间无明显界线,细胞排布有所区别.从外侧到内侧,顶盖可分为带状层、外灰质层、浅白质层、中灰质层、中白质层、深灰质层、深白质层和中央灰质. 被盖前部分层与顶盖相同,中后部分层不明显.神经细胞主要在灰质内,白质中零星分布一些小细胞.视叶室的形状由前向后不同.同时对扬子鳄中脑视叶同其他脊椎动物的进行了比较讨论.     

扬子鳄胚胎十二指肠的组织发生

本文观察了１８例不同时间扬子鳄胚胎十二指肠的组织发生过程。孵化第１０天十二指肠出现形态分化。１６天,上皮细胞增殖为３￣４层,．肠腔扩大．３０天,上皮局部出现突起,多具２层细胞。３４天,间充质已分化为固有膜、粘膜下层、环行肌层及纵行肌层,环行肌层较厚,平均约为２８μｍ。４０天,上皮为单层柱状,纹状缘明显,开始出现原始小肠腺。５２天,杯状细胞较多。６２天,各层结构与成体时相似;扫描电镜下观察,绒毛为指     

乌江上游四川裂腹鱼幼鱼发育的观察

室内１６－２８℃条件下，孵出后约１２小时，胸鲁原基出现，鳃弧也出现；卿出后第２天，眼黄色素出现，卿出后第４天，眼出现黑色素；孵出后第９天，鳔出现，鱼苗营沸合营养２；孵出第１１天，背鳍褶显著隆起；第１８天，卵黄物质被吸收贻尽：进入稚鱼阶段；孵出后第３０天，腹鲁芽出现；孵出后第３４天，背鳍形成；孵出后第４９天，腹鳍形成；孵出后第６２天，鳍化结束并出现凳须。     

秦岭滑蜥中脑视叶组织学结构观察

光镜下观察了秦岭滑蜥（Scincella tsinlingensis）中脑视叶的组织学结构.秦岭滑蜥中脑视叶分为背侧的顶盖和腹侧的被盖两部分,两者之间无明显界限.顶盖处灰质和白质交替排列.神经细胞主要在灰质内,白质中有小细胞零星分布.由深层至表层依次为室管膜层、深白质层、深灰质层、中白质层、中灰质层、浅白质层、外灰质层和分子层.被盖处细胞层次不明显.左右视叶与中脑水管在视叶中部相通.视叶前部有横行的纤维将左右视叶联系起来.与其他脊椎动物中脑的比较结果表明秦岭滑蜥在爬行类进化上处于较低等地位.     

脊髓水平的痒觉神经环路以及信息传递研究进展

脊髓背角接受痒觉以及痛觉的初级传人.在脊髓背角存在多种神经元并形成杂神经元环路,外周的痒觉信息也在脊髓背角神经元中整合换元并传递到高级中枢.脊髓背角神经元在痒觉信号的传递中发挥重要的作用,本文就脊髓背角神经元的细胞构筑以及痒觉信号传递在脊髓水平的神经回路作简要综述.     

扬子鳄胚胎味蕾发生的初步观察

在４例不同时期的扬子鳄胚胎中观察了味蕾的形态发生及细胞分化过程。孵化至第４８天，部分舌乳头上皮的基部出现味蕾原基。第５２天味蕾体积增大，细胞数量显著增多。第５６天部分味蕾出现味孔，味蕾细胞出现基细胞、支持细胞和味觉细胞的分化。第６２天味蕾的味孔均形成，部分味孔扩大，味毛增多并伸出味孔外。味觉细胞在分化过程中，其细胞核内的异染色质及细胞质中的线粒体均逐渐增多。     

发育不同时期幼鼠脊髓中ZBTB-38基因的表达

为了探讨ZBTB-38基因在胚胎发育时期脊髓中的表达及其在脊髓结构中的表达定位,取幼鼠发育5天,10天,15天,20天,25天(P5,P10,P15,P20,P25)的脊髓,利用免疫组织化学SABC和RT-PCR法,对脊髓中ZBTB-38基因的表达进行检测.结果显示:幼鼠脊髓发育过程中,ZBTB-38阳性表达主要分布在灰质前角,并且随着发育的不同时期表达呈一定的动态变化,在P5时开始上升,P15达到高峰,随后维持在一定的生理水平.     

一氧化氮合酶阳性神经元在小鼠颈髓的分布

用ＮＡＤＰＨ－ｄ组织化学方法观察小鼠颈髓一氧化氮合酶阳性神经元的分布,结果显示在颈髓的胶状质和中央管周围灰质内有较多一氧化氮合酶神经元分布,在前角基部内侧有较大的ＮＯＳ神经元,这些神经元大多显示Ｇｏｌｇｉ样染色外观,它们尚不能与任何已知的神经递质类型神经元单一对应,后角浅层的中间带分别含有密集和中等密集的ＤＯＳ阳性纤维,一氧化氮合产阳性神经元的纤维较细,有串珠状膨大,相互交织成疏密度不等的网络。     

大、小鼠颈髓一氧化氮合酶阳性神经元的分布比较

用NADPH—d组织化学方法观察了大鼠和小鼠颈髓内NOS阳性神经元的分布，结果显示在大、小鼠颈髓的中央管周围灰质内均有较多的NOS阳性神经元分布，大鼠的NOS阳性神经元多集中于中央管背侧，小鼠的分布相对均匀，但以腹侧为多，大、小鼠在后角浅层及胶状质内部均含有密集的NOS阳性神经元，在中间带内侧也均含有较大的中等密集的NOS阳性神经元。大鼠中间带外侧有较多的NOS阳性神经元，而小鼠该处的NOS阳性神经元则少见，结果提示NOS阳性神经元在实验动物颈髓的分布存在种属间差异。     

大白鼠坐骨神经再生轴突可塑性的研究——辣根过氧化物酶(HRP)示踪观察

用HRP逆行示踪法,对成年大白鼠两侧坐骨神经端端吻合术后,再生轴突可塑性作了研究。术后1—12月不同时间内,在吻合端左侧0.8cm处,再横断坐骨神经,放入HRP,存活2天,取材观察。结果表明:所有动物脊髓腰骶段两侧前角均出现HRP标记细胞。标记细胞数量随吻合术后时间增长而增加。左侧前角较右侧前角标记细胞多。说明受损的坐骨神经轴突能再生,各自进入对侧的坐骨神经,向脊髓方向延伸。但是,仅部分再生轴突能延伸过缝合处的组织痂。本实验提示再生轴突的可塑性,它受环境因素的影响。     

扬子鳄胚胎背部皮肤及鳞甲的发生

本文观察了１６例不同时间的扬子鳄（Ａｌｌｉｇａｔｏｒ ｓｉｎｅｎｓｉｓ）胚胎背部皮肤及鳞甲的形态和组织发生过程，孵化第２０天，来自胚胎中胚层生皮节的间充质细胞开始向有皮下迁移，表皮仅具周皮层与生发层两层细胞，第２８天背部鳞片开始明显，左右鳞片之间出现很浅的鳞间沟，前后鳞片交界处的原始表皮，真皮层开始向外突出形成鳞甲原基，第３４天鳞甲原基突出伸长，第４０天背鳞的纵嵴明显，第３４－５０天中，鳞甲后级基     

Sensory transmitters regulate intracellular calcium in dorsal horn neurons

Primary afferent terminals in the dorsal horn of the spinal cord release excitatory amino acid and peptide transmitters that initiate the central processing of nociceptive information. The postsynaptic actions of amino acid transmitters on spinal neurons have been well characterized, but the cellular basis of peptide actions remains unclear. Substance P is the best characterized of the peptides present in sensory neurons and has been shown to depolarize dorsal horn neurons and to facilitate nociceptive reflexes. To determine the mechanisms by which substance P contributes to afferent synaptic transmission, we have monitored the levels of intracellular calcium in single isolated rat dorsal horn neurons and report that substance P can produce a prolonged elevation in calcium concentration by mobilizing its release from intracellular stores. This elevation may contribute to the long-term changes in the excitable properties of dorsal horn neurons that occur following afferent fibre stimulation. We have also found that L-glutamate elevates intracellular calcium in substance P-sensitive dorsal horn neurons by increasing calcium influx. These results provide a direct demonstration of intracellular calcium changes in response to neuropeptides in mammalian central neurons. They also indicate that there is convergent regulation of intracellular calcium in dorsal horn neurons by two different classes of sensory transmitters that are co-released from the same afferent terminals.     

Induction of c-fos-like protein in spinal cord neurons following sensory stimulation

It has been suggested that the proto-oncogenes c-fos and c-myc participate in the control of genetic events which lead to the establishment of prolonged functional changes in neurons. Expression of c-fos and c-myc are among the earliest genetic events induced in cultured fibroblast and phaeochromocytoma cell lines by various stimuli including growth factors, peptides and the intracellular second messengers diacylglycerol, cAMP and Ca2+. We report here that physiological stimulation of rat primary sensory neurons causes the expression of c-fos-protein-like immunoreactivity in nuclei of postsynaptic neurons of the dorsal horn of the spinal cord. Activation of small-diameter cutaneous sensory afferents by noxious heat or chemical stimuli results in the rapid appearance of c-fos-protein-like immunoreactivity in the superficial layers of the dorsal horn. However, activation of low-threshold cutaneous afferents results in fewer labelled cells with a different laminar distribution. No c-fos induction was seen in the dorsal root ganglia, gracile nucleus or ventral horn. Thus, synaptic transmission may induce rapid changes in gene expression in certain postsynaptic neurons.     

ATP excites a subpopulation of rat dorsal horn neurones

The peripheral receptive properties and central projections of different classes of dorsal root ganglion neurones are well characterized. Much less is known about the transmitters used by these neurones. Excitatory amino acids have been proposed as sensory transmitters but the sensitivity of virtually all central neurones to those compounds has made it difficult to assess their precise role in sensory transmission. Several neuropeptides have been localized within discrete subclasses of primary sensory neurones that project to the superficial dorsal horn of the spinal cord and may be afferent transmitters. However, only about one-third of spinal sensory neurones have been shown to contain neuropeptides. We have recently described the presence of a 5'-nucleotide hydrolysing acid phosphatase in a separate subpopulation of dorsal root ganglion neurones that project to the superficial dorsal horn. This enzyme also appears in certain autonomic and endocrine cells that contain high concentrations of releasable nucleotides in their storage granules. It is possible that the presence of this enzyme in sensory neurones is also associated with a releasable pool of nucleotides. Holton and Holton have provided evidence that ATP is released from the peripheral terminals of unmyelinated sensory fibres and have suggested that release of ATP might also occur from central sensory terminals. To investigate the possibility that nucleotides act as central sensory transmitters we have examined their actions on rat dorsal horn and dorsal root ganglion neurones maintained in dissociated cell culture. We report here a selective and potent excitation of subpopulations of both neuronal types by ATP.     

A gastrin-releasing peptide receptor mediates the itch sensation in the spinal cord

Itching, or pruritus, is defined as an unpleasant cutaneous sensation that serves as a physiological self-protective mechanism to prevent the body from being hurt by harmful external agents. Chronic itch represents a significant clinical problem resulting from renal diseases and liver diseases, as well as several serious skin diseases such as atopic dermatitis. The identity of the itch-specific mediator in the central nervous system, however, remains elusive. Here we describe that the gastrin-releasing peptide receptor (GRPR) plays an important part in mediating itch sensation in the dorsal spinal cord. We found that gastrin-releasing peptide is specifically expressed in a small subset of peptidergic dorsal root ganglion neurons, whereas expression of its receptor GRPR is restricted to lamina I of the dorsal spinal cord. GRPR mutant mice showed comparable thermal, mechanical, inflammatory and neuropathic pain responses relative to wild-type mice. In contrast, induction of scratching behaviour was significantly reduced in GRPR mutant mice in response to pruritogenic stimuli, whereas normal responses were evoked by painful stimuli. Moreover, direct spinal cerebrospinal fluid injection of a GRPR antagonist significantly inhibited scratching behaviour in three independent itch models. These data demonstrate that GRPR is required for mediating the itch sensation rather than pain, at the spinal level. Our results thus indicate that GRPR may represent the first molecule that is dedicated to mediating the itch sensation in the dorsal horn of the spinal cord, and thus may provide a central therapeutic target for antipruritic drug development.     

乌鳢尾部神经分泌系统组织化学和HRP法研究

采用辣根过氧化物酶(HRP)法结合乙酰胆碱酯酶(AChE)和单胺氧化酶(MAO)组化方法,对乌鳢尾部神经分沁系统进行了研究。结果如下: 1.在尾部脊髓中可以观察到一些HRP标记的神经分泌细胞和HRP标记末梢。有些标记末梢终止于脊髓中央管,少量终止于腹面脊膜。尾垂体中也有许多HRP标记末梢。2.神经分泌细胞细胞体中的HRP颗粒在电镜下呈圆形、短管状和哑铃状。3.神经分泌细胞体显示AChE活性,并定位于核膜、粗面内质网上。4.神经分泌细胞体周围尚显示MAO活性。     

Peripheral nerve injury triggers central sprouting of myelinated afferents.

The central terminals of primary afferent neurons are topographically highly ordered in the spinal cord. Peripheral receptor sensitivity is reflected by dorsal horn laminar location: low-threshold mechanoreceptors terminate in laminae III and IV (refs 2, 3) and high-threshold nociceptors in laminae I, II and V (refs 4,5). Unmyelinated C fibres, most of which are nociceptors, terminate predominantly in lamina II (refs 5, 7). There is therefore an anatomical framework for the transfer of specific inputs to localized subsets of dorsal horn neurons. This specificity must contribute to the relationship between a low-intensity stimulus and an innocuous sensation and a noxious stimulus and pain. We now show that after peripheral nerve injury the central terminals of axotomized myelinated afferents, including the large A beta fibres, sprout into lamina II. This structural reorganization in the adult central nervous system may contribute to the development of the pain mediated by A-fibres that can follow nerve lesions in humans.