Morphological characteristics of a unique intracytoplasmic neuronal inclusion body

Summary Unique intracytoplasmic inclusion bodies unaccompanied by a clinically apparent neurologic disease were found in the neurons of the hippocampus, subiculum, and mammillary body of a man who died suddenly, presumably of cardiac disease. The eosinophilic inclusions were round and often targetoid, with a central core that had the staining characteristics of RNA. Ultrastructurally, the inclusions were mainly composed of osmiophilic granular material. Rabies viral antigen was not detected by immunofluorescence, and heavy metals were not detected by energy dispersive spectrometry. These neuronal inclusions should be distinguished from Negri bodies.     

Chondroitin 4-sulfate proteoglycan forms an extracellular network in human and rat central nervous system

Chondroitin 4-sulfate proteoglycan (C4S-PG) was localized both in rat and human central nervous system (CNS) by monoclonal and polyclonal antisera recognizing the 4-sulfate disaccharide (C4S). In the rat the whole CNS was studied in serial coronal sections. A positive extracellular meshwork was observed both in white and grey matters. In the white matter (WM) C4S-PG formed a network around myelinated axons, sparing myelin sheaths and axoplasms. The neuropil of the grey matter (GM) showed a positive meshwork constituted by delicate intermingling filaments. The cytoplasms of neuronal, glial and endothelial cells were negative. Stronger straining than in the neuropil was observed around the soma and the proximal part of the cell processes of some neurons located in the cortex, in the deep cerebellar nuclei and in some other CNS nuclei. A similar pattern was also observed in human CNS, the only difference being a smaller amount of cortical neurons surrounded by a rim of C4S-PG. This study shows that a PG bearing C4S disaccharide is located extracellularly in the rodent and human CNS and that C4S disaccarides can be present in different types of CNS proteoglycans (PGs).     

The total number,time of origin and kinetics of proliferation of neurons comprising the deep cerebellar nuclei in the rhesus monkey

Summary The genesis of the neurons that form the cerebellar nuclei was studied by autoradiographic methods in 30 postnatal rhesus monkeys which were exposed to ³H-thymidine at various embryonic (E) and postnatal (P) ages. As a basis for this quantitative analysis, five 2–3 month old monkeys were used for cell counting and estimation of the total number of neurons in each of the cerebellar nuclei. The results show that the cerebellar nuclei on each side contain 131,000 neurons. There are 68,000 neurons in the dentate nucleus, 25,000 neurons in the posterior interposed nucleus, and 19,000 neurons in both the anterior interposed and fastigial nuclei. All of the neurons comprising the deep nuclei are generated during the first half of the 165 day gestation period in this species. Although neurogenesis lasts from E30 through E70, approximately 81% of the neuron population is generated during a one week period between E36 and E40, with the peak of proliferation occurring at E36. Before E45 both large (maximum diameter greater than 35 m) and small (maximum diameter 35 m or less) neurons are produced simultaneously; after this period only small neurons are generated. Although no clearcut spatio-temporal gradients of neurogenesis could be discerned along any of the cardinal axes, each cerebellar nucleus has a somewhat distinctive developmental history in terms of the onset and cessation of neurogenesis and the tempo of cell proliferation. Thus, genesis of neurons destined for the dentate nucleus begins earlier and ends later than proliferation of the neurons that ultimately comprise the fastigial nucleus. Generation of the neurons destined for the anterior and posterior interposed nuclei follows an intermediate time course. The present data on neurogenetic sequences in the deep nuclei could not be correlated with the zonal pattern of reciprocal axonal connections that link the deep nuclei and overlying cerebellar cortex.This work was supported by U.S.P.H.S. Grant NS 14841 and Postdoctoral Fellowship NS 06061     

Cell-specific role for epsilon- and betaI-protein kinase C isozymes in protecting cortical neurons and astrocytes from ischemia-like injury

Activation of epsilon protein kinase C (epsilonPKC) has been shown to protect cardiac myocytes against ischemia and reperfusion injury. However, the role of PKC in ischemic brain injury is less well defined. Western blot analysis of murine neurons and astrocytes in primary culture demonstrated epsilon- and betaIPKC expression in both cell types. Activation of epsilonPKC increased in neuronal cultures in response to the ischemia-like insult of oxygen-glucose deprivation (OGD). Isozyme-specific peptide activators or inhibitors of PKC were applied at various times before, during and after the OGD period. Neuron-astrocyte mixed cultures pretreated with a selective epsilonPKC activator peptide showed a significant reduction in neuronal injury after OGD and reperfusion, compared to cultures pretreated with control peptide. The epsilonPKC activator peptide counteracted the increased damage induced by pretreatment with the epsilonPKC-selective inhibitor peptide in relatively pure neuronal cultures subjected to OGD. Neither epsilonPKC activator nor inhibitor peptides affected injury of neurons when applied after OGD onset. In contrast, the betaIPKC-selective inhibitor peptide increased injury in astrocyte cultures exposed to OGD at all application times tested. Our data demonstrate protection of neurons by selective activation of epsilonPKC but enhanced astrocyte cell death with selective inhibition of betaIPKC. Thus PKC isozymes exhibit cell type-specific effects on ischemia-like injury.     

针刺对胃运动异常大鼠调节作用的神经机制研究

目的 探讨迷走神经中枢孤束核在针刺足三里、内关、中脘、气海调节胃运动中的作用机制。方法 采用神经电生理学方法，用微电极细胞外记录大鼠孤束核单个神经元的活动，在正常生理状态下及经血管注射抑制胃运动的药物阿托品或促进胃运动的药物胃复安后观察针刺上述穴位对孤束核神经元放电的影响。结果 在正常生理状态下，针刺上述穴位均可有效激活孤束核神经元放电。静脉注射阿托品后，孤束核神经元背景放电减少；静脉注射胃复安后，孤束核神经元背景放电增加；但针刺对放电的影响与药物前相比，变化均不大，阿托品后或者胃复安后针刺上述穴位仍町有效激活孤束核神经元放电。结论 针刺足三里、内关、中脘、气海对胃运动的调节作用与孤束核神经元的激活密切相关。孤束核是以上穴位与胃联系途径中的一个重要初级中枢。     

正己烷接触对血清神经元特异烯醇化酶及髓鞘碱性蛋白的影响

目的研究正己烷接触对血清神经元特异烯醇化酶(NSE)及髓鞘碱性蛋白(MBP)的影响。方法分别对接触组37名及对照组49名工人应用酶联免疫吸附法测定其NSE及MBP的血清含量。结果接触组和对照组的血清NSE含量分别为(8.4±7.7)、(7.8±3.2)μg/L,接触组的血清NSE水平高于对照组(P<0.05);血清MBP含量分别为(1.59±0.54)、(0.94±0.27)μg/L,接触组明显高于对照组(P<0.05)。结论正己烷接触可导致血清NSE及MBP升高。     

牛磺酸锌对染汞大鼠大脑皮层NADPH-d阳性神经元的影响

目的 探讨牛磺酸锌(TZC)拮抗汞(Hg)对大鼠大脑皮层神经细胞的损害作用.方法 选用出生后21 d的健康雄性Wistar大鼠32只,随机分为4组,每组8只,即对照组(饮用单蒸水,普通饲料)、单纯染Hg组(饮用0.06 g/L HgCl2水溶液,普通饲料]、Hg 低TZC组(饮用含0.06 g/L HgCl2和0.23 g/L TZC的水溶液,普通饲料)、Hg 高TZC组(饮用含0.06 g/LHgCl2和0.46 g/L TZC的水溶液,普通饲料).大鼠Hg的摄入量控制在4.3 mg/(kg·d),单蒸水和TZC溶液为自由饮取,染毒时间为1个月.采用NADPH-黄递酶(NADPH-d)组化方法,观察了饮用0.06 g/LHgCl2水溶液和不同浓度(0.23、0.46 g/L)TZC的大鼠大脑皮层一氧化氮合酶(NOS)活力的变化以及体重增量的变化.结果 与对照组比较,单纯染Hg组大鼠皮层NADPH-d阳性细胞率升高(P＜0.05),体重增量降低(P＜0.05);与单纯染Hg组相比,Hg 高TZC组NADPH-d阳性细胞率降低(P＜0.05),体重增量升高(P＜0.05).结论 TZC在一定程度上能拮抗Hg对大鼠大脑皮层神经细胞毒性作用.     

新生儿高胆红素血症患儿脑干听觉诱发电位及血清神经元特异性烯醇化酶变化及临床意义

目的通过对新生儿高胆红素血症患儿脑干听觉诱发电位(BAEP)及血清神经元特异性烯醇化酶(NSE)检测,评估高胆红素血症对新生儿听神经损伤。方法 56例血清胆红素大于 220．5μmol／L的新生儿为高胆红素血症组(简称高胆组),血清胆红素小于220．5μmol／L的49例足月儿为对照组,分别进行BAEP、NSE检测。结果高胆组新生儿BAEP的Ⅰ、Ⅲ、Ⅴ波绝对潜伏期(PL)、峰间潜伏期(IPL)均明显延长,与对照组比较,差异有显著性意义(P<0．01);高胆组新生儿NSE明显高于对照组,差异有显著性意义(P<0．01);NSE水平与BAEP的Ⅴ波反应阈值呈正相关(r=0．65,P<0．01)。结论高胆红素血症可导致新生儿听神经损伤;BAEP和NSE对其神经损伤有较高的敏感性,可作为监测指标。     

高碘对小鼠大脑神经细胞超微结构的影响

目的 研究高碘对小鼠大脑海马组织形态和神经细胞超微结构的影响。方法 用随机区组法将动物随机分为高碘、低碘、适碘三组,复制高碘、低碘甲状腺肿动物模型,观察其仔一代鼠１５日龄时的大脑海马组织形态和神经细胞超微结构。结果 高碘组大脑海马神经细胞核浓缩、胞浆增多,特别是核周的细胞质减少消失,出现了“空晕”现象。超微结构显示,高碘组神经细胞核肿胀变性,异染色质明显减少,结构松懈,部分区域丢失,胞质内线粒体肿     

新生大鼠中枢神经系统不同区域细胞生长的形态学比较研究

目的分离培养新生sD大鼠的中枢神经系统不同区域细胞并观察其生长情况．方法分离出生后1～3dSD大鼠大脑皮质、小脑皮质、海马、脑室下区、脑干、脊髓细胞，加入含有10％小牛血清的DMEM／F12培养基进行培养，在倒置相差显微镜下观察其生长情况并进行对比研究，于第10天将细胞固定后采用免疫细胞化学技术检测特异性神经元抗原NSE和特异性星形胶质细胞抗原GFAP的表达．结果经观察和免疫细胞化学鉴定后发现各区域均有神经元和星形胶质细胞生长至第10天，细胞生长旺盛，神经元胞体呈三角形或椭圆形，体积较大，四周晕光明显，神经突起多而粗大，分枝互成网络；星形胶质细胞细胞核为椭圆形，常偏于胞体的一侧，胞突丰富，分支多．结论我们培养成活了新生SD大鼠中枢神经系统各区域细胞．对比研究了各区域细胞的生长情况．并鉴定了各区域中的神经元和星形胶质细胞．