P物质在成年猫脊髓和背根节的分布

目的 观察P物质在成年猫脊髓和背根节的表达情况。方法 成年健康雄猫5只，取L5脊髓节和随机取一侧L6背根节制作厚20μm冰冻切片，用免疫组织化学ABC法染色，观察SP在正常脊髓和背根节的分布。结果 在脊髓，SP阳性膨体主要见于后角Ⅰ、Ⅱ板层，后角Ⅳ、Ⅴ、Ⅵ板层及侧角的一些神经元呈弱阳性反应，前角运动神经元胞体和突起呈阳性反应，胞核不着色。在背根节，SP的免疫阳性物主要分布于小细胞的胞浆内，胞核不着色。结论 SP在成年猫脊髓和背根节有表达。     

Caspase-3在成年猫脊髓和背根节的分布

目的采用免疫组织化学方法探讨Caspase-3在成年猫脊髓和背根节的分布。结果Caspase-3的阳性反应物主要分布于脊髓前角、中间带(包括背核)、后角深部以及背根节(DRG)的中小神经元。此外在脊髓白质亦有大量胶质细胞着色。结论Caspase-3参与上述部位的细胞凋亡或其它功能的调控。     

Sema3A及其受体NP-1分别在成年猫脊髓及背根节中的表达

目的探讨正常状态下smea3A在成年猫脊髓,其受体neuropiln-1（NP-1）在背根节（DRG）的分布.方法选取成年雄猫5只,用免疫组织化学方法检测脊髓中sema3A,DRG中NP-1的分布.结果脊髓中sema3A的阳性反应物主要分布于腹角的绝大部分运动神经元的胞浆;背根节中NP-1阳性产物主要分布在部分中小神经元及少量大神经元的胞浆中.结论脊髓中的sema3A可能抑制了背根节神经元在脊髓中的错误出芽,从而保持了脊髓中正常突触联系的稳定性.     

针刺对备用背根节神经元表皮生长因子表达的影响

成年哺乳动物的脊髓具有可塑性,且针刺可促进脊髓可塑性,但其机制尚不清楚。有实验表明针刺可促进NGF、NT-3在部分去背根动物背根节的表达,表明了针刺可能通过改变背根节部分神经营养因子的表达进而在脊髓可塑性中发挥作用。表皮生长因子(EGF)与神经     

雪旺细胞源神经营养因子对背根节感觉神经元的保护作用

目的：了解雪旺细胞源神经营养因子对周围神经高位损伤所致脊髓背根节感觉神经元死亡的保护作用。方法：选出生3周SD鼠高位切断L4、L5神经根，神经近侧断端应用雪旺细胞源神经营养因子或生理盐水，4周后观察损伤神经根背根节感觉神经元的存活率和形态学变化。结果：术后4周，营养因子组神经元的存活率是91．8％，生理盐水组是58．6％；生理盐水组存活神经元胞体明显萎缩。结论：雪旺细胞源神经营养因子对受损的背根节感觉神经元有明显的神经营养活性．     

GABA_A和GABA_B受体介导的成年动物背根神经节神经元的电活动

许多药理学研究表明，哺乳动物脊髓背角中的GABA受体亚型（GABAA和GABAB）参与介导脊髓初级传入末梢的突触前抑制。本研究应用细胞内记录技术探讨GABAB受体激活对背根神经节细胞膜电特性的作用。实验标本取自SD成年大鼠L4～6后根节和猫在体L6～7后根节。当灌流液加入GABAB受体激动剂baclofen时，后根节的98个细胞中，约58％的细胞无反应。部分A类和C类细胞的膜电位出现超极化（n＝37）和去极化（n＝14）反应。A传入（n＝71）和C传入（n＝27）激活的反应没有明显的差异。Baclofen引起的DRG细胞的去极化和超极化反应可被GABAS受体选择性拮抗剂saclofen阻断。一些对baclofen反应的细胞也可被GABAA受体激动剂muscimol去极化。在所记录的细胞中，baclofen对动作电位时程（APD50）没有明显的影响。上述结果提示，在部分细胞中，baclofen激活的GABAB受体介导细胞膜电位去极化和超级化反应。GABAA和GABAB这二种受体不仅在慢传速的Aδ和C类细胞中共存，同样也共存于快传速的Aα和Aβ的细胞膜上。     

基于GC V算法的背根节神经元放电信号的滤波

为去除背根节神经元放电信号中的噪声,便于进一步分析信号,采用小波滤波法。先将含噪信号采用haar小波进行5层分解,然后在传统小波软阈值滤波的基础上,提出用GCV算法来确定最优阈值,最后进行信号重构。通过matlab仿真实验表明,采用了GCV算法的滤波方法能有效去除神经元放电信号中的噪声,去噪后信号光滑连续好,并且保留了信号峰值的相关细节。     

吗啡对备用根大鼠背根节神经元胞体的影响—光镜和电镜观察

用光镜体视学方法，结合电镜观察，探讨发生侧支出芽和重要建突触的背根节神经元，其胞体是否也呈现相应的形态变化，以及吗啡对这些变化的影响。吗啡备用根组和备用根对照组的大鼠术侧背根节体积与非术侧比较，均没有显著的统计学差异；其亮神经元胞体、胞核和核仁的体积也没有显著性差异。对照组非术侧亮神经元胞体的尼氏体呈颗粒状，多聚核糖体聚集成小簇，分散在胞质中。术侧尼氏体则呈小块状，多聚核糖体簇较大，较为密集。吗啡     

成年弥猴背根神经节nNOS免疫阳性神经元的分布

目的：观察正常成年称猴背根神经节神经元型一氧化氮合酶(nNOS)免疫阳性神经元的分布。方法：ABC免疫细胞化学方法显示nNOS免疫阳性神经元，并用体视方法进行定量分析。结果：猕猴颈、胸、腰各段背根神经节nNOS免疫阳性神经元的分布相似，数量较多，阳性神经元的大小不等，多呈圆形或椭圆形；胞浆着色较深，胞核位于细胞中央，不着色，细胞被神经纤维束分隔成群。nNOS免疫阳性神经元以中型神经元为主，其次为小型神经元，其胞浆呈强阳性染色，细胞直径＜50μm，大型神经元较少。颈、胸、腰各段背根神经节nNOS免疫阳性神经元的密度以及阳性细胞与总细胞数的比值均无明显差异。结论：称猴背根神经节nNOS主要表达在中、小型神经元，提示NO可能主要参与痛觉等浅感觉的传导和调制。     

体外获得高纯度大鼠背根神经节神经元的原代培养

目的：建立一种切实可行的胚胎大鼠背根神经节神经元培养及纯化方法。方法：用显微解剖获取足够数量的胚胎大鼠背根神经节,通过胰蛋白酶+EDTA消化、交替使用NB培养基与加入了5-氟-2-脱氧尿嘧啶核苷酸/尿苷的抗有丝分裂NB培养基等方法,在体外获得纯化的背根神经节神经元,采用神经丝蛋白免疫细胞化学染色法与DAPI染核的方法鉴定并测定神经元的纯度。结果：获得的背根神经节神经元在体外生长良好,纯度可达到96%以上。结论：本实验方法可以获得大量高度纯化的大鼠背根神经节神经元。     

Effects of neonatal capsaicin administration on the numbers and volumes of neurons in left and right T10 dorsal root ganglia in the rat

The long-term effects of neonatal capsaicin were studied in left and right dorsal root ganglia (T10) from control and capsaicin-treated groups of Wistar rats. At 12 hours post partum, 5 females per group were injected subcutaneously with capsaicin or vehicle solution and killed at 6 months of age. Tissues were perfusion-fixed, embedded in resin and serially sectioned. A Nissl stain was used to distinguish between A and B neurons and systematic random sampling schemes were employed to obtain stereological estimates of numbers of neurons and mean volumes of their perikarya. Numbers were calculated from ganglion volumes (estimated via the Cavalieri principle) and neuron packing densities (estimated using physical disectors). Mean perikaryal volumes were calculated from packing densities and volume densities (estimated by point counting). Data were analysed to isolate main and interaction effects of neuron subtype, laterality and treatment. There was no evidence of lateral asymmetry or interaction effects. Control ganglia contained 3320 (coefficient of variation, CV, 8%) neurons. Most (73%) were B cells with a mean volume of 13,100 µm³ (CV 17%) of which the nucleus accounted for 1,800 µm³ (CV 18%). About 22% were A cells with a mean volume of 79,800 µm³ (CV 24%) and a nucleus of 6,100 µm³ (CV 26%). After capsaicin, over half the original population of cells was destroyed and B cell loss was significantly greater than that of A cells (about 80% of all cells lost were B cells). The mean size of A cells was greater after capsaicin due to selective loss of smaller cells and a greater volume of cytoplasm. B cell perikaryal volume was not affected but nuclear volume declined. The findings show that capsaicin destruction of peripheral sensory neurons is bilaterally symmetrical. In general, smaller neurons are selectively destroyed but this operates differently in A and B cells. It is size-dependent in A cells but size-independent (possibly random) in B cells.     

神经节苷脂对损伤胎鼠背根神经节的保护作用

目的观察神经节苷脂(GM1)对受损伤胎鼠背根神经节(DRG)神经元形态改变的影响,探讨其可能的保护作用。方法选择胎龄为15d的SD大鼠为研究对象,获取DRG神经元并进行体外分散培养,培养48h后,随机分为对照组、谷氨酸损伤组和谷氨酸损伤+GM1保护组,继续培养12h。终止培养后,观察各组神经元的形态结构改变,用MTT法鉴定细胞的存活率。结果对照组DRG神经元细胞贴壁呈单层散在分布,少部分出现细胞聚集现象,突起较长且互相交织形成网状。谷氨酸损伤组DRG神经元细胞聚集现象明显,神经元突起变短、断裂甚至消失。谷氨酸损伤+GM1保护组DRG神经元细胞部分呈簇状聚集,部分呈单个散在分布,突起仍然相互交织。MTT结果显示谷氨酸损伤+GM1保护组细胞存活率高于谷氨酸损伤组。结论神经节苷脂可以影响损伤胎鼠DRG神经元的形态改变,对胎鼠背根神经节神经元具有一定的保护作用。     

家兔内脏大神经传入神经元的节段分布

为探明内脏大神经传入神经元在后根节内的节段分布,本研究将家兔的左侧内脏大神经中枢侧断端浸泡于HRP溶液中。其HRP标记细胞的节段范围为胸_2——胸_(12)节,并以胸_5——胸_(11)节为多。91.2%HRP标记细胞的直径在34微米以下。     

外周神经损伤大鼠背根神经节中Ephrin B1及RYK 受体表达的变化

目的研究外周神经损伤后背根神经节细胞中Ephrin B1及其相关受体的表达变化。方法建立一侧坐骨神经夹伤的大鼠动物模型,通过免疫荧光组织化学方法检测受损侧背根神经节细胞中Ephrin B1及其相关受体Eph B1、Eph B2、Eph B3和Eph A4、RYK等的表达,并分析阳性细胞数和不同大小阳性细胞的构成比例。结果外周坐骨神经受损侧背根神经节细胞中Ephrin B1的表达明显减弱,而Eph B1、Eph B2、Eph B3和Eph A4受体的表达无明显变化,但RYK受体的表达则明显加强。结论Ephrin B1和RYK受体在一侧外周坐骨神经夹伤后的大鼠背根神经节细胞中表达的变化,说明它很有可能参与了损伤后的功能活动。     

高糖对体外培养背根神经节神经元影响的研究进展

背根神经节神经元(DRGn)在糖尿病周围神经病变发展过程中起重要作用,近年来探讨高糖对体外培养背根神经节神经元(DRGn)的影响成为研究热点.高糖环境可致DRGn细胞凋亡;同时高糖环境下DRGn在氧化应激、膜受体mGluRs及TRPV1激活、DRGn/SCs共培养等方面均与正常培养基不同,具体机制仍需深入研究.     

Ultrastructural cytochemical localization of carbonic anhydrase activity in rat peripheral sensory and motor nerves, dorsal root ganglia and dorsal column nuclei

Some of the myelinated axons in rat peripheral nerves possess marked axoplasmic carbonic anhydrase activity [Riley, Ellis and Bain (1982) J. Histochem. Cytochem. 30, 1275-1288; Riley and Lang (1984) J. Hand Surg. 9A, 112-120]. A mixture of reactive and nonreactive neurons was a general observation in cervical, thoracic and lumbar ganglia. Nonmyelinated axons in lumbar dorsal roots were nonreactive; this was consistent with the lack of carbonic anhydrase in small sensory neurons. The carbonic anhydrase cytochemical method marked the larger afferent or sensory neurons and distinguished them from the smaller sensory neurons which were devoid of carbonic anhydrase activity. Nonmyelinated axons in the lumbar ventral roots were also nonreactive. Examination of muscle spindle innervation revealed staining of the primary sensory and gamma motor endings. This was strongly suggestive that some of the reactive sensory neurons were primary afferents and a portion of the reactive ventral root axons were gamma motor. The reactive central processes of spinal neurons sent collaterals into the grey matter of the spinal cord, entered the dorsal funiculi, and terminated in synaptic glomeruli in the cuneate and gracilis nuclei. Oligodendroglial cells appeared to be the only intrinsic cellular elements of the brain stem and spinal cord that exhibited high carbonic anhydrase activity. Both oligodendroglial and Schwann cells exhibited intense carbonic anhydrase activity in thin pockets of cytoplasm internal to compact myelin. The subcellular distribution of reaction product within sensory neurons and oligodendroglial cells agreed with biochemical reports of cytosol and membrane-bound forms of carbonic anhydrase. A general staining of the cytoplasm was suggestive of soluble carbonic anhydrase fixed in situ by the glutaraldehyde. Clumps of reaction product on the cytoplasmic surface of the endoplasmic reticulum possibly represented membrane-bound enzyme. Most of the membrane-bound carbonic anhydrase was associated with the internal membranes rather than the axolemma or limiting plasma membrane of the axon. In contrast to biochemical reports, a small fraction of neuronal mitochondria exhibited staining in the intracristal spaces. We suggest that the association of carbonic anhydrase with endoplasmic reticulum and mitochondria implicates the enzyme in regulating intracellular calcium because both organelles are known to sequester calcium.     

Monoclonal antibody 2C5: a marker for a subpopulation of small neurones in rat dorsal root ganglia

Monoclonal antibody 2C5 labels a subset of dorsal root ganglion neurones in the rat. The cell sizes of these neurones fall within the range for the small dark cell population and the antibody labels between a half and two-thirds of the neurones in this size range. A subpopulation of small neurones was also labelled in the trigeminal and vagal ganglia. Other sites of immunoreactivity in the central nervous system are the region of the substantia gelatinosa of the spinal cord, fibres in Lissauer's tract, the tractus solitarius and the tuberculum olfactorium. These sites are consistent with the antigen being expressed by the central processes of primary afferent neurones. It is suggested that the size distributions of 2C5-positive dorsal root ganglion neurones and the pattern of 2C5 immunoreactivity within the spinal cord indicate that the labelled cells may be neurones with peripheral C fibers. Outside the nervous system the antigen is expressed in a number of specific cell types within a variety of organs. These include some pancreatic acinar cells, parietal cells of the gastric mucosa, some cells in taste buds, Leydig cells of the testis, scattered cells in lymph nodes and lung alveoli, some renal tubules, the epithelial lining of the fallopian tube, the epithelium covering the ovary and certain cells in the basal layer of the epidermis.     

Hyperalgesic priming is restricted to isolectin B4-positive nociceptors

We have previously described a rat model for the contribution of neuroplastic changes in nociceptors to the transition from acute to chronic pain. In this model a prior injury activates protein kinase C epsilon (PKCε), inducing a chronic state characterized by marked prolongation of the hyperalgesia induced by inflammatory cytokines, prototypically prostaglandin E₂ (PGE₂), referred to as hyperalgesic priming. In this study we evaluated the population of nociceptors involved in priming, by lesioning isolectin B4-positive (IB4(+)) nociceptors with intrathecal administration of a selective neurotoxin, IB4-saporin. To confirm that the remaining, TrkA(+)/IB4(−), nociceptors are still functional, we evaluated if nerve growth factor (NGF) induced hyperalgesia. While pretreatment with IB4-saporin eliminated the acute mechanical hyperalgesia induced by glia-derived neurotrophic factor (GDNF), NGF and ΨεRACK, a highly selective activator of PKCε, induced robust hyperalgesia. After injection of NGF, GDNF or ΨεRACK, at a time at which hyperalgesia induced by PGE₂ is markedly prolonged (hyperalgesic priming) in control rats, in IB4-saporin-pretreated rats PGE₂ failed to produce this prolonged hyperalgesia. Thus, while PKCε is present in most dorsal root ganglion neurons, where it can contribute to acute mechanical hyperalgesia, priming is restricted to IB4(+)-nociceptors, including those that are TrkA(+). While PKCε activation can induce acute hyperalgesia in the IB4(+) population, it fails to induce priming. We suggest that hyperalgesic priming occurs only in IB4(+) nociceptors, and that in the peripheral terminals of nociceptors separate intracellular pools of PKCε mediate nociceptor sensitization and the induction of hyperalgesic priming.     

坐骨神经损伤后脊神经节神经元凋亡的形态学观察

周围神经损伤后，神经修复困难的原因之一是一定数量的神经元胞体死亡。运用NGF可保护感觉神经元胞体免于死亡，但对于细胞死亡的性质目前尚未肯定，因而对NGF的保护机理也就不清楚。本研究通过对大鼠坐骨神经切断再吻合后，观察其脊神经节感觉神经元的胞体形态变化，认为神经元死亡的主要形式是细胞凋亡(apoptosis)。