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。     

Effects of cryogenic blockade of visual cortex on the responses of lateral geniculate neurons in the monkey

Summary Striate cortex in unanesthetized, paralyzed rhesus monkeys was cooled to assess the effects of temporary blockade of corticogeniculate fibers on responses of lateral geniculate neurons. Most neurons recorded under the thermode became inexcitable on cooling. After the onset of cooling, superficial layers became inexcitable before deep layers, and at a time when superficial activity was blocked, deep neurons were still orientation specific and retained this property until they themselves became inexcitable.Twenty-eight percent of the geniculate neurons projecting to cortex under the thermode were judged to be affected by cortical blockade, generally showing increases in driven and spontaneous activity. Cooling produced changes in the scale of response magnitude, rather than in the timing of impulse discharge, as evaluated by response time histograms. Responses evoked by bars or edges or by flashing spots were equally affected.The changes of activity produced were generally small and frequently difficult to differentiate from spontaneous shifts in excitability. In contrast, a visually driven inferior pulvinar neuron with a receptive field in the cooled area was strongly affected by cortical blockage, and driving quickly and completely returned soon after the cortex was rewarmed. It therefore appears that the method of blockade was effective but incapable of producing large effects in geniculate neurons. This suggests that cortical control may be inherently weak in the immobilized animal or that the distribution of activity between excitation and inhibition is equally balanced.This research was supported by National Institutes of Health Research grant 5 R01 EY00927 and by National Institutes of Health Training grant in Physiology 5 T01 GM00443     

Quantitative estimation of morphological changes in the central nervous system

A quantitative method of estimating the degree of morphological changes in neurons of the CNS is suggested. The following groups of altered neurons are distinguished: a swollen neuron with initial signs of breaking up of tigroid masses, a swollen neuron with marked evidence of breaking up of tigroid masses and initial signs of hypochromatosis, a swollen neuron with total tigrolysis and with hyper- and hypochromatosis, a dehydrated hyperchromic neuron, a vacuolated neuron, a shrunken, atrophic neuron, and a dying neuron. For a more precise and objective assessment of the observed changes, each of these groups is given a certain number of points characterizing the degree of the morphological changes. A formula is suggested for evaluating the degree of morphological changes for different formations and zones of the CNS.     

Amphetamine induces dendritic growth in ventral tegmental area dopaminergic neurons in vivo via basic fibroblast growth factor

Dopaminergic neurons of the ventral tegmental area are implicated in the physiology of reward, and long-lasting changes in their function induced by exposure to psychostimulant drugs are related to the pathophysiology of drug abuse. It is not known, however, whether such changes are accompanied by morphological changes in these neurons. We characterized and labeled cells in slices containing the ventral tegmental area using whole-cell electrophysiological methods. Injections of saline or amphetamine were given to rats on postnatal days 10, 12 and 14 and individual neurons were examined one to four weeks later. We show that repeated exposure to amphetamine induces substantial dendritic growth of ventral tegmental area dopaminergic neurons in vivo. Furthermore, we show, by immuno-neutralization of endogenous basic fibroblast growth factor, that the amphetamine-induced increase in astrocytic basic fibroblast growth factor in the ventral tegmental area is essential for these morphological changes. We propose that the amphetamine-induced elaboration of the dendritic arbor of dopaminergic neurons leads to their increased excitability and contributes to compulsive drug-seeking and relapse.     

不同年龄双峰驼海马的形态学变化及其神经生长因子的表达

目的 探讨胎驼、青年双峰驼及成年双峰驼海马不同区域内主要神经元形态特征变化及神经生长因子（NGF）的表达情况。 方法 应用常规石蜡切片Nissl染色及免疫组织化学方法,对胎驼、青年双峰驼和成年双峰驼海马CA1～CA3区锥体细胞、齿状回（DG)颗粒细胞的形态学变化进行研究,并观察了NGF的表达变化情况。 结果 Nissl染色结果显示,从胎驼到青年双峰驼再到成年双峰驼,海马各区锥体细胞和颗粒细胞的体积增大、密度降低、细胞的核体比减小。NGF免疫组织化学结果表明,成年双峰驼海马锥体细胞中NGF的表达量显著高于胎驼和青年双峰驼（P<0.01）,颗粒细胞中NGF的表达量逐渐增加。 结论 从胎驼到成年双峰驼,海马中的主要神经元不断成熟,从体积小且少有突起和分支的神经元发育成为体积较大、具有明显形态和功能的神经元。NGF在成年双峰驼海马神经元中表达量最高,表明NGF可调节已分化的神经元,使其形态和功能发生改变以促进成年双峰驼与海马相关的学习记忆功能的逐步完善。     

Morpho-functional characteristics of the spinal cord neurons after one-time integrating motor activity

To investigate the adaptive morphological changes of cellular elements of the spinal cord following the dosed application of physical loads (running in treadmill for 7-35 min), the motor neurons and interneurons of i.v. lumbar spinal cord segment were studied in 38 mongrel male dogs. It was shown that single integrating physical loads contributed to significant increase in the number of functionally active neurons. It is noted that the morphological changes are more pronounced in the motor neurons as compared to interneurons.     

大鼠腹侧中脑多巴胺能神经元的形态学发育与分布特征

目的:探讨大鼠腹侧中脑多巴胺能(mDA)神经元的形态学发育和分布特征。方法:取胚胎晚期至成年大鼠不同时期的腹侧中脑连续冠状切片,以酪氨酸羟化酶(TH)免疫荧光染色方法观察mDA神经元。结果:(1)在胚胎期,TH阳性细胞多为圆形或椭圆形,随着发育进程,其突起逐渐伸长,分支也逐渐增多;出生后28 d,TH阳性细胞表现为成熟mDA神经元的形态特征。(2)Map-2/TH免疫荧光检测显示,新生期大鼠腹侧中脑TH阳性神经元定位分布与成年期的mDA神经元分布趋向一致。(3)E16.5 d时腹侧中脑TH阳性细胞的数量和密度最大,此后逐渐下降。结论:大鼠mDA神经元的发育在出生前后,呈现先大量形成后又逐渐减少的过程,与此同时其形态趋向成熟;至P0 d时mDA神经元分布定位基本完成,至出生后28 d形态学发育成熟。     

Microelectrode recording of responses in visually observed neurons of the cat motor cortex

With a contact optical system it is possible to carry out intravital studies of neurons and other structures, stained with vital dyes in reflected light in a specially prepared specimen of the cat cerebral cortex. The high-quality characteristics of the optical system used have made combined morphological and intracellular electrophysiological investigations of these neurons possible. The nature of intravital morphological changes in cortical neurons was established in response to their puncture by microelectrodes with tips with different external diameters and configurations; certain morpho-functional correlations were found in the response of pyramidal neurons to disturbance of their temperature regime.Translated from Neirofiziologiya, Vol. 8, No. 2, pp. 122–125, March–April, 1976.     

Changes in the Morphology of Hypoglossal Motor Neurons in the Brainstem of Developing Rats

The autonomic brainstem generates breathing rhythm by integrating inputs from chemosensors and mechanosensors in the viscera and coordinating descending outputs from higher structures in the central nervous system. Hypoglossal motoneurons (XII MNs) receive inputs from respiratory premotor neurons, important for maintaining airway patency. Previous studies in rodents report significant changes in breathing control during the first 3 weeks of life, with a sensitive period at 10 to 13 days postbirth (P10–P13) characterized by pronounced changes in neurotransmitters, excitation-inhibition balance, and breathing physiology. However, age-dependent morphological changes of XII MNs during the first 3 weeks postbirth and especially this sensitive period are under-studied. Here, we comprehensively characterize and quantify the early morphological changes in rat XII MNs. We hypothesized that morphological changes in XII MNs correspond to the functionally defined sensitive period observed at postnatal day 10–13 (P10–P13). To test this hypothesis, we used an innovative contemporary statistical approach to analyze Golgi-Cox stained XII MNs at nine postnatal ages between P1 and P21. Our findings reveal two subpopulations of XII MNs, which are dependent on age and morphological features. Soma size increased approximately 40% from P1 to P21, without changing shape. However, dendritic arborization increased in extent/distance and complexity. Dendritic branching of developing neurons significantly increased from P1 through P13, with the greatest increase at P10–P13 based on the Sholl method. Our detailed characterization of XII MN morphological development establishes a foundation for the study and elucidation of morphological changes caused by maternal and perinatal conditions. Anat Rec, 302:869–892, 2019. © 2018 Wiley Periodicals, Inc.     

The influence of exercise on morphological and neurochemical properties of neurons in rat nodose ganglia

Physical exercise can induce immunohistochemical changes and cell proliferation in the hippocampus. One of the main effects of prolonged exercise is resting bradycardia, most probably caused by enhanced vagal activity. To investigate whether physical exercise can cause neurochemical and morphological changes in vagal afferent neurons, we performed immunohistochemical studies of nodose neurons using isolectin B4 (IB4), 200-kDa neurofilament protein (N52) and calretinin in adult female rats. To distinguish subpopulations of neurons projecting to the left ventricle, we applied a Fast Blue patch to the epicardial surface of the left ventricle. Treadmill running for 8 weeks significantly increased the size of N52-positive cardiac projecting neurons. Furthermore, the proportion of IB4-positive neurons among all nodose ganglia neurons was significantly higher in trained animals. These data indicate that exercise leads to plastic changes in nodose ganglia neurons that may initiate changes of vagal activity caused by prolonged exercise.     

Structure of the Sensorimotor Area of the Cerebral Cortex in the Offspring of Alcoholized Rats

Light and electron microscopy and morphometry were used to study the characteristics of the cytoarchitectonics of the sensorimotor cortex and the structures of neurons and their dendrites in 21- and 30-day-old baby rats born to chronically alcoholized females and males. Three categories of morphological changes were identified: signs of delayed maturation of neurons and dendrites, destructive changes to these structures, and signs of repair processes, with dynamics occurring during postnatal ontogenesis. At age three weeks, apart from delayed maturation of neurons and underdevelopment of the dendritic system, there were also spreading destructive changes. Increasing age was associated with increases in repair processes, though destructive changes to neurons persisted, which is evidence for the delayed action of alcohol intoxication of animals on the structural development of the brain in their offspring.     

Electron-microscopic changes of the brain in acute experimental peritonitis (AEP)

It is shown that changes in the vessels of the central nervous system, neurons and interneuron links--synapses develop in AEP. Increasing diffuse-focal destructive brain changes are morphological substrate of toxico-hypoxic encephalopathy and basis for disturbances of an integrative-trigger action of the brain.     

不同时程应激对大鼠下丘脑弓状核和室周核神经细胞的影响

目的:观察不同时程应激对大鼠下丘脑弓状核和室周核神经细胞的影响及酪氨酸羟化酶(TH)的表达变化,为应激性损伤的机制研究提供病理形态学依据。方法:建立每日束缚固定8 h加冰水游泳5 min的应激大鼠模型,分为1、3、7、14、21d组及各时间点正常对照组,采用硫堇染色观察弓状核、室周核内神经细胞尼氏体变化及细胞形态学改变;TH免疫组织化学标记观察大鼠下丘脑弓状核和室周核内多巴胺能神经细胞阳性表达变化,采用全景组织细胞定量分析系统,进行统计分析。结果:较长时程反复的应激刺激导致了大鼠弓状核和室周核神经细胞细胞质内尼氏体消失及部分细胞固缩。TH免疫组织化学标记显示随着应激时程的延长,下丘脑弓状核和室周核内多巴胺能神经细胞阳性表达数目减少。结论:较长时程的反复应激刺激可导致大鼠下丘脑弓状核和室周核神经细胞损伤及多巴胺能神经细胞缺失。     

Differential effects of prenatal stress on the morphological maturation of hippocampal neurons

The present study was designed to clarify an intensity-dependent effect of prenatal stress on the morphological development of hippocampal neurons in rats. In addition, the involvement of receptors for glucocorticoids, i.e. mineralocorticoid receptors and glucocorticoid receptors, in stress-induced changes in the morphology of hippocampal neurons was examined by an in vitro pharmacological approach. The effects of mild prenatal stress on neurogenesis and long-term potentiation in the hippocampus were also investigated in adult offspring. Prenatal stress affected the morphological development of the hippocampus in an intensity-dependent manner. Short-lasting, mild prenatal stress enhanced neonatal neurogenesis and differentiation of processes of hippocampal neurons, whereas long-lasting, severe stress impaired their morphology. Mineralocorticoid receptor was found to mediate enhancement of neurogenesis and differentiation of processes of cultured hippocampal neurons. In contrast, glucocorticoid receptor was involved in the suppression of their morphology. Short-lasting, mild prenatal stress, which has previously been shown to enhance learning performance in adult offspring, facilitated neurogenesis and long-term potentiation in the adult hippocampus. These findings suggest that prenatal stress has enhancing and suppressing effects on the development of hippocampal neurons depending on intensity, and that mineralocorticoid receptors and glucocorticoid receptors contribute to stress-induced morphological changes.     

Ageing changes in the transplants of fetal substantia nigra grafted to striatum of adult rat.

Fetal nigral neurons from 16 and 17 gestational days were transplanted into the intact striatum of adult rat. On different post-transplantation days (30-360 days), the structural and immunohistochemical details of the transplants were studied. The grafted neurons matured and showed phenotypical characteristics comparable to that of normal nigral neurons in adult rats until 180 days. Tyrosine hydroxylase-positive neurons were seen not only in the transplant but also in the adjacent host striatum. Tyrosine hydroxylase-positive fibres were also seen extending for a short distance into the host striatum. A large number of synapses in the transplants were of asymmetric type, containing clear round vesicles. These synapses resembled the few intrinsic type present in the normal substantia nigra. On the other hand, the predominant type 2 synapses with pleomorphic vesicles in the normal nigra were infrequently encountered in the transplants. On the 300th day, the cytoplasm of a few of the neurons showed ageing changes in the form of clear spaces, paucity of organelles especially rough endoplasmic reticulum, membrane-bound vacuoles and increase in the lipofuscin population. In addition, localized thickening of the soma and the dendrites were seen in relation to randomly distributed neurons. By 360 days, more than one quarter (26%) of the total neurons showed these changes indicating ageing. The number per unit volume of normal neurons decreased significantly when compared to the transplants on 60 and 90 days. In the substantia nigra of age-matched control, except for an increase in the lysosomal population, other ageing changes were not detectable. The neurons of intact substantia nigra of the host rat, chronologically 4-8 months older than the transplanted neurons, also appeared normal but for lipofuscin granules. The present study provides morphological evidence for rapid ageing of neurons in the long term nigral transplants. These observations raise fresh doubts regarding permanent survival of grafted neurons in the host brain. Studies so far conducted are after prior nigral lesions. Trophic factors following lesions of the host tissue may have influenced the long term survival of the transplanted neurons. On the other hand, such changes may have been missed since no detailed morphological investigations of the long term transplants have been done so far.     

肝性脑病大鼠海马齿状回神经元形态及一氧化氮合酶表达的变化

目的:观察肝性脑病模型组大鼠海马齿状回内神经元的变化及一氧化氮合酶(NOS)的表达,探讨海马神经元的形态学改变及一氧化氮(NO)在肝硬化和肝性脑病发病机制中的作用。方法:先对50只雄性大鼠进行Morris水迷宫测试,之后将动物分为正常对照组和实验模型组。9周后建立CCL4肝性脑病模型,分别取两组大鼠肝、海马组织进行HE染色、Nissl染色及NADPH-d染色。结果:(1)肉眼下可见模型组肝脏普遍呈坏死性肝硬化;(2)HE模型组血氨浓度明显高于正常对照组(P<0.05);(3)Nissl染色结果显示实验组大鼠海马神经元数目减少、染色较浅,胞浆内Nissl体减少或消失;(4)NADPH-d染色结果显示实验组可见粗大轴突着色,树突联系广泛;对照组则少有粗大轴突着色,树突间联系不如实验组广泛。实验组一氧化氮合酶(NOS)阳性神经元染色较对照组深,为紫蓝或深蓝色,且阳性神经元的数目较多。结论:(1)血氨增高是肝性脑病发病机制之一;(2)肝性脑病时海马受到损伤,并且一氧化氮(NO)可能介导了神经元的损伤。     

Novel non-apoptotic morphological changes in neurons of the mouse hippocampus following transient hypoxic-ischemia

Apoptosis has been recently implicated in the dying process of neurons under several pathological conditions including ischemia. However, although apoptosis was originally defined on the basis of its unique ultrastructural features (Kerr et al., 1972. Br. J. Cancer 26, 239-257; Wyllie et al., 1980. Int. Rev. Cytol. 68, 251-306), unambiguous ultrastructural evidence of apoptosis has been rarely demonstrated in the adult brain. In this study, we examined ultrastructural changes in mouse hippocampal neurons after transient hypoxic-ischemia. A small population of dentate granule cells showed typical apoptotic ultrastructures that could be used as internal morphological standards of apoptosis, whereas most other hippocampal neurons consistently showed a distinct form of cellular disintegration. Nuclei of the latter cells shrank and became TUNEL-positive but were distinguishable from apoptotic nuclei by both the presence of characteristic reticular-formed chromatin condensation and the absence of nuclear fragmentation. Perikarya of degenerating neurons also shrank as in apoptosis, but apoptotic bodies were not observed. Although organelles other than mitochondria disappeared almost completely from the perikarya, neither plasma nor mitochondrial membranes were disrupted, indicating that these changes were also different from typical necrosis. The presence of a novel form of cell death suggests the necessity of morphological re-examination of neuronal death, particularly in mature neurons in vivo.     

远志皂苷元对H2O2诱导的大鼠海马神经元损伤的影响及其机制

目的: 观察远志皂苷元(senegenin, Sen)对过氧化氢(H₂O₂)诱导的SD大鼠海马神经元损伤的影响并探讨其作用机制。方法: SD大鼠海马神经元培养至第6 d,随机分为正常组、H₂O₂组、Sen+ H₂O₂ 组和Sen组,药物干预后检测细胞存活率、丙二醛(MDA)含量和超氧化物歧化酶(SOD)活性,并用 Hoechst 33258染色观察细胞核形态变化,荧光定量PCR(real-time PCR)检测神经元凋亡相关基因 bcl-2和bax 的表达,进一步采用Western blotting观察Bcl-2和Bax蛋白表达,酶荧光活性检测试剂盒测定caspase-3的活性改变。结果: 与正常组相比,H₂O₂组细胞存活率降低。与H₂O₂组相比,20 μmol/L Sen+ H₂O₂ 组细胞存活率升高,SOD活性升高,MDA含量下降,并且远志皂苷元能够上调bcl-2 mRNA表达、下调bax mRNA表达,降低caspase-3活性,Western blotting结果进一步表明Bcl-2蛋白表达升高,Bax蛋白表达下降,各指标均有显著差异(P<0.05)。结论: 远志皂苷元对H₂O₂处理的海马神经元有一定保护作用,其机制可能与远志皂苷元增强海马神经元抗氧化能力、调节细胞凋亡相关蛋白从而抑制凋亡有关。     

Age-related changes of the nucleolar organizer regions without neuron loss in medial mamillary bodies (hypothalamus) in old rats.

Age-related morphological and functional changes were studied in the medial mamillary nuclei of the hypothalamus (MMN). The number of nerve cells and the volume of MMN were estimated in both groups of Wistar rats, adult and old (3 and 22 months, respectively) using stereologic methods such as the optical fractionator and Cavalieri's method respectively. The number of neurons and glial cells remain inalterable with ageing but there was an age-dependent reduction in MMN volume. In the second experiment, functional changes in the MMN neurons were observed although there was no loss in neuron number. Several functional parameters of the Ag-NORs were quantified by a computer analysis system: area and number of Ag-NORs per neuron; number of neurons with one or several Ag-NORs and also surface of neuronal nucleus. The present study shows how ageing causes volumetric and functional changes in the MMN whereas the number of neurons and glial cells remain unchanged in the mamillary region. All these results confirm the effects of age on proteic synthesis activity in neurons of the MMN, showing a decreased neuronal activity in this region.     

Age-correlated changes in dopaminergic nigrostriatal perikarya of the C57BL/6NNia mouse

Alterations in neurotransmitter systems of the basal ganglia have been postulated to contribute to the disruption of motor function and balance associated with aging. This study examined nigrostriatal (A9) and mesolimbic (A10) dopamine neurons for qualitative age-correlated changes using fluorescence histochemistry for catecholamines and immunocytochemical techniques for the catecholamine-synthesizing enzyme, tyrosine hydroxylase. Results from this study suggest that age-correlated morphological changes in A9 but not all A10 neurons in the midbrain are present in mature adult (10-month) C57BL/6NNia mice and show a progressive increase in severity until at least 30 months of age. These changes are characterized by a progressive accumulation of lipofuscin in dopamine-containing perikarya, a markedly reduced dopamine content per cell as determined visually by histofluorescence, and an increase in the number of large, fluorescent axonal dilations in dopamine-containing fibers of the mesolimbic and nigrostriatal systems. These data suggest that heterogeneous morphological aging patterns exist within dopamine-containing neurons of the midbrain and that based upon their terminal projection sites, various regions of the striatum and cortex may be differentially affected in the aged brain. In addition, these findings support the belief that age-related changes in neural structure are not generalized to an entire brain nucleus or cell type but are selective for individual cells within an affected area.