Ultrastructural Localization of Synaptophysin to the Secretory Granules of Normal Glucagon and Insulin Cells in Human Islets of Langerhans

Immunogold labeling of the pancreatic islets in humans by means of monoclonal antibodies to synaptophysin resulted in a distinct localization of gold particles to the secretory granules of glucagon-immunoreactive cells. The same type of immunoreactivity was noted with antiserum to chromogranin A. Glucagon immunoreactivity was concentrated in the dense central core of the secretory granules. Some immunoreactivity for synaptophysin was also found in the secretory granules of the insulin-producing cells, although it was weaker in this location.     

Molecular milestones that signal axonal maturation and the commitment of human spinal cord precursor cells to the neuronal or glial phenotype in development.

Insights into the programmatic induction of neuronal and glial genes during human embryogenesis have depended largely on extrapolations of data derived from experimental mammals. However, the assumptions upon which these extrapolations are based have not been rigorously tested. Indeed, practically no information is available even on the human counterparts of the relatively small subset of well-characterized, developmentally regulated neuron and glial specific genes of the mammalian CNS. Thus, the developmental programs upon which human neural embryogenesis are based remain largely undeciphered. We have addressed this problem in immunohistochemical studies conducted on 22 human fetal spinal cords with gestational ages (GAs) that ranged from 6 to 40 weeks by using monoclonal antibodies to several classes of neuron or glial specific polypeptides. These polypeptides included: representatives of four different types (Types I-IV) of intermediate filament proteins, i.e., vimentin filament protein (VFP), glial fibrillary acidic protein (GFAP), different phospho-isoforms of the high (NF-H), middle (NF-M), and low (NF-L) molecular weight (Mr) neurofilament (NF) subunits, both acidic and basic cytokeratin (CK) proteins; three different microtubule associated proteins (MAPs), i.e., MAP2, MAP5, and tau; two different synaptic or coated vesicle proteins, i.e., synaptophysin (SYP) and clathrin light chain B (LCb); an oligodendroglial specific protein, i.e., myelin basic protein (MBP); and a receptor for a CNS trophic factor, i.e., the nerve growth factor receptor (NGFR).(ABSTRACT TRUNCATED AT 400 WORDS)     

Effect of Panaxtriol Saponins on synaptophysin and postsynaptic density-95 expression at different periods of cerebral infarction

BACKGROUND:The change in expression of synaptophysin (Syp) and postsynaptic density-95 (PSD-95) alters after cerebral infarction,and the plasticity of synapses contributes greatly to nerve function recovery. Chinese medicinal substances may play an important role in the expression of Syp and PSD-95. OBJECTIVE: To observe the effect of Panaxtriol Saponins (PTS),an active component in Sanqi tongshu capsules,on the expression of Syp and PSD-95 after cerebral infarction at different time points in rats,so as to...     

New Method for Imaging Innervation of the Renal Preglomerular Vasculature. Alterations in Hypertensive Rats

Objective : To develop a new method for viewing adrenergic innervation along renal preglomerular vessels; to assess nerve densities and vascular lesions along arcuate arteries (ArcA), arcuate arterial branches (ArcB), and interlobular arteries (ILA) in spontaneously hypertensive rats (SHR) and in angiotensin II (AngII) and in N^G‐nitro‐l ‐arginine methyl ester (l ‐NAME) hypertensive rats. Methods : Preglomerular vasculatures were isolated after HCl maceration and were immunostained against synaptophysin, a membrane protein of synaptic vesicles. Lesions were stained with Sudan black. Longitudinal nerve densities and relative frequencies of ArcA, ArcB, and ILA endowed with sudanophilic lesions were assessed separately. Results : Synaptophysin immunostaining revealed the vascular neural plexus. Nerves were adrenergic, as the plexus was destroyed by treatment with 6‐hydroxy dopamine. Vascular lesions were not seen in SHR, and increased nerve density was observed along ArcA and ILA. In l ‐NAME‐ and AngII‐hypertensive rats, vascular lesions affected predominantly ArcB and ILA, and nerve density was reduced by 12% and 28% (ArcA), 37% and 31% (ArcB), and by 55% and 34% (ILA), respectively, versus normotensive controls. Endothelin‐1 receptor blockade did not affect AngII‐induced hypertension but prevented both lesion development and reduction of density of the vascular neural plexus. Conclusions : The method we have devised provides a direct en face view of the vascular adrenergic innervation of isolated preglomerular vasculature. Measurements in hypertensive rat models suggest a link between vascular lesions and reduction in nerve density in hypertension. Endothelin‐1 likely plays a key role in mediating both vascular injury and altered vascular nerve density in hypertension.     

Immunolocalization and quantitation of a novel nerve terminal protein in spinal cord development

In the adult spinal cord, the neuron-specific protein NT75 is located in nerve terminals synapsing in the superficial laminae of the dorsal horn. The present study examines the occurrence of NT75 in the developing rat spinal cord. NT75 immunoreactivity is detectable in primary afferent axons at the dorsal root entry zone on embryonic day 15. Subsequently, staining of presumptive nerve terminals appears in the deeper laminae of the dorsal horn, expanding into the superficial laminae during the first postnatal week. NT75 staining also appears in developing corticospinal tract axons in the brainstem at birth, and at lumbosacral levels by postnatal day 5. As NT75-positive nerve terminals approach the adult distribution, staining of primary afferent and corticospinal axons decreases, becoming undetectable by postnatal day 30. Dense transient staining of presumed nerve terminals in the ventral horn is also apparent during early postnatal development. Quantitative analysis of developing spinal cord shows a low level of NT75 immunoreactivity at birth. NT75 activity then increases substantially, reaching values by the third and fourth postnatal weeks up to 2.5 times that seen in adults. The occurrence of NT75 immunoreactivity correlates with the reported time course of synaptic development in the spinal cord. In addition, the results suggest that NT75 immunoreactivity is maintained at high levels in the nerve terminals of certain neural pathways into adulthood, whereas in other systems NT75 immunoreactivity may be detectable only during development.     

转基因小鼠脑组织中突触素和发动蛋白Ⅰ及衔接蛋白180表达的变化

目的探讨瑞典型淀粉样前体蛋白突变基因转基因小鼠脑组织中突触素(synaptophysin)、发动蛋白Ⅰ(dynamin Ⅰ)及衔接蛋白180(AP180)表达变化。方法选择6只瑞典型淀粉样前体蛋白突变基因转基因小鼠为转基因组,另选5只小鼠为对照组。采用免疫组织化学染色法检测小鼠海马及颞叶皮质synaptophysin、dynamin Ⅰ及AP180的表达,图像分析半定量;免疫组织化学双染法观察转基因小鼠脑组织中synaptophysin与β淀粉样蛋白(Aβ)_(1-42)在老年斑表达部位的关系。结果与对照组比较,转基因组小鼠脑组织齿状回分子层、海马CA1、CA3及内嗅区皮质各层synaptophysin平均灰度值明显增高(P0.05,P0.01);齿状回颗粒细胞、海马CA1锥体细胞及内嗅区皮质各层dynamin Ⅰ平均灰度值明显增高(P0.05,P0.01);齿状回分子层、海马CA4、CA1、内嗅区皮质各层及颞叶皮质Ⅱ～Ⅴ层AP180平均灰度值明显增高(P0.05,P0.01)。免疫组织化学双染显示转基因组小鼠老年斑内有synaptophysin和Aβ_(1-42)共同存在。结论转基因小鼠脑组织中synaptophysin、dynamin Ⅰ及AP180表达降低,提示出现不同程度突触丧失及突触囊泡回收功能缺陷,可能是该小鼠认知功能障碍的原因之一。     

参乌胶囊及其有效成分二苯乙烯苷对老年大鼠海马神经元突触体素表达的影响

目的观察由首都医科大学宣武医院药物研究室自行研制的抗老年性痴呆中药新药参乌胶囊(Shen-wu capsule,SW)及其有效成分何首乌二苯乙烯苷(tetrahydroxystilbene glucoside,TSG)对于老年大鼠海马神经元突触结构和突触体素表达的影响,阐明其防治神经元退行性变的机制。方法选用老年SD大鼠,从21月龄始,分别灌胃给予SW(0.8 g/kg、1.6 g/kg)和TSG(0.03 g/kg、0.06 g/kg)至24月龄。以6月龄大鼠为青年对照,未给药24月龄大鼠为老年对照。应用通道式水迷宫试验检测大鼠学习记忆能力,用电子显微镜观察脑海马神经元突触超微结构,用免疫组织化学染色检测海马神经元突触体素(synaptophysin,SYP)的表达。结果与6月龄青年对照组大鼠相比,24月龄老年大鼠通道式水迷宫试验错误次数明显增多(P<0.01);给予SW和TSG的老年大鼠在高剂量组可见水迷宫错误反应次数显著减少,与老年对照组相比差异具有统计学意义(P<0.01)。电子显微镜结果显示,24月龄老年大鼠神经元突触数量明显减少;而给予TSG大剂量灌胃组突触数量增多,并可见类似于突触球的结构。免疫组织化学染色结果可见24月龄大鼠SYP染色明显变浅,累积光密度值低(P<0.01);而灌胃给予SW和大剂量TSG组大鼠SYP表达量明显升高,差异具有统计学意义(P<0.01)。结论参乌胶囊及其有效成分二苯乙烯苷对于老年大鼠的神经元突触靶位具有较好的疗效,本结果为其在临床用于延缓衰老、改善认知功能提供了实验基础。     

梓醇对大鼠梗死灶周围大脑皮质神经元树突生长及突触素表达的影响

目的观察梓醇对局灶脑缺血大鼠梗死灶周围大脑皮质(peri-infarction cortex,PIC)锥体神经元树突生长及突触素p38蛋白表达的影响,探讨其促脑卒中后神经修复作用及机制。方法 57只清洁级成年SD大鼠,随机分为假手术组,模型组,生理盐水组,梓醇低、中、高剂量(分别为1、5、10 mg·kg-1)组和胞磷胆碱(0.5 g·kg-1)对照组。开颅电凝右侧大脑中动脉制备局灶永久性脑缺血模型。于造模后24 h开始腹腔注射不同剂量梓醇或胞磷胆碱,每日1次,连续7d。术后1、4、7和15 d采用角落实验评估神经缺失功能恢复状况;术后1 d和15 d磁共振成像测量脑梗死体积;术后15 d,断头取脑,Golgi-Cox染色显示PIC区锥体神经元树突变化,免疫荧光组织化学染色及Western blot检测PIC区突触素p38蛋白表达。结果梓醇各剂量组和胞磷胆碱组术后7 d和15 d神经功能恢复明显优于模型组和生理盐水组(P<0.05);术后1 d、15 d,各实验组脑梗死体积差异无显著性(P>0.05);梓醇中剂量组PIC区锥体神经元树突分支数和树突棘密度均比模型组、生理盐水组和胞磷胆碱组明显增加(P<0.05);梓醇各剂量组PIC区突触素p38表达均比模型组、生理盐水组和胞磷胆碱组明显上调(P<0.05)。结论梓醇可增强局灶脑缺血大鼠PIC区锥体神经元树突可塑性,上调突触素p38表达,促进神经缺失功能恢复。     

铅对小鼠学习记忆功能影响与突触囊泡蛋白相关

目的探讨小鼠海马中突触囊泡蛋白与铅对小鼠学习记忆功能影响的相关性。方法将雄性昆明小鼠24只,随机平均分为两组,对照组和铅染毒组,对照组饲以蒸馏水,铅染毒组饲以2.4mmol/L的醋酸铅水溶液,在暴露后30d,进行Morris水迷宫实验以检测其逃逸潜伏期,采用Western blot法检测海马中突触囊泡蛋白水平,并采用HE切片方法观察处理前后小鼠海马脑区病理变化。结果 Morris水迷宫结果显示铅暴露后30d可导致小鼠逃逸潜伏期延长(P<0.05),且暴露后30d铅染毒组小鼠海马中突触囊泡蛋白表达显著减少(P<0.05),但脑组织HE切片显示铅暴露30d后并未引起脑组织海马脑区病理学改变。结论慢性铅暴露可导致小鼠学习记忆功能损伤,且这种损伤可能与其海马中突触囊泡蛋白表达下降有关。     

Medulloblastoma with myogenic differentiation showing double immunopositivity for synaptophysin and myoglobin

Reported herein is a case of medulloblastoma with myogenic differentiation in a 3-year-old girl who died 1 year after appearance of clinical signs. Magnetic resonance imaging indicated a mass lesion in the cerebellar vermis. She underwent total resection of the tumor, followed by chemotherapy and radiotherapy in the brain and spinal cord. The resected specimen mainly consisted of densely packed cells with round-to-oval highly chromatic nuclei surrounded by scanty cytoplasm and focally of long spindle-shaped cells with elongated nuclei and eosinophilic cytoplasm showing discernible cross-striations. Immunohistochemistry indicated partial expression of synaptophysin in the former area and focal expression of desmin in the latter area. The diagnosis was medulloblastoma with myogenic differentiation, also known as medullomyoblastoma. Autopsy indicated disseminated proliferation of immature neuroglial cells with highly chromatic nuclei and scanty cytoplasm showing partial expression of synaptophysin, neurofilaments, and GFAP, and focal proliferation of round-to-oval immature cells showing immunoreactivity of myoglobin. The tumor cells had large nuclei, frequent mitoses, apoptoses, nuclear molding, and cell wrapping, indicating moderate anaplasia. Their Ki-67 labeling index was 54%. In addition, some tumor cells had double immunopositivity for synaptophysin or neurofilament and myoglobin, suggesting that the neuroectodermal cells may undergo differentiation into rhabdomyoblasts.