Effects of ring finger and tryptophan-aspartic acid 2 on dendritic spines and synapse formation in cerebral cortex neurons of mice / 南方医科大学学报

OBJECTIVE@#To clarify the functional effects of differential expression of ring finger and tryptophan-aspartic acid 2 (RFWD2) on dendritic development and formation of dendritic spines in cerebral cortex neurons of mice.@*METHODS@#Immunofluorescent staining was used to identify the location and global expression profile of RFWD2 in mouse brain and determine the co-localization of RFWD2 with the synaptic proteins in the cortical neurons. We also examined the effects of RFWD2 over-expression (RFWD2-Myc) and RFWD2 knockdown (RFWD2-shRNA) on dendritic development, dendritic spine formation and synaptic function in cultured cortical neurons.@*RESULTS@#RFWD2 is highly expressed in the cerebral cortex and hippocampus of mice, and its expression level was positively correlated with the development of cerebral cortex neurons and dendrites. RFWD2 expression was detected on the presynaptic membrane and postsynaptic membrane of the neurons, and its expression levels were positively correlated with the length, number of branches and complexity of the dendrites. In cultured cortical neurons, RFWD2 overexpression significantly lowered the expressions of the synaptic proteins synaptophysin (P < 0.01) and postsynapic density protein 95 (P < 0.01), while RFWD2 knockdown significantly increased their expressions (both P < 0.05). Compared with the control and RFWD2-overexpressing cells, the neurons with RFWD2 knockdown showed significantly reduced number of dendritic spines (both P < 0.05).@*CONCLUSION@#RFWD2 can regulate the expression of the synaptic proteins, the development of the dendrites, the formation of the dendritic spines and synaptic function in mouse cerebral cortex neurons through ubiquitination of Pea3 family members and c-Jun, which may serve as potential treatment targets for neurological diseases.

Effect of Baihe Dihuang Decoction on synaptic plasticity of hippocampus in rats with anxious depression / 中国中药杂志

To explore the effect of Baihe Dihuang Decoction on the synaptic plasticity of hippocampal neurons in rats with anxious depression. Fifty SD rats were randomly divided into normal group, model group, venlafaxine group(6.75 mg·kg~(-1)), high-dose Baihe Dihuang Decoction group(8.64 g·kg~(-1)) and low-dose Baihe Dihuang Decoction group(4.32 g·kg~(-1)). Chronic restraint stress(6 h) combined with corticosterone(ih, 30 mg·kg~(-1)) was used to establish an anxious depression model, and 7 days after modeling, the administration started and continued for 21 days. The anxiety and depression-like behaviors of the rats were evaluated. Golgi-Cox staining and electron microscopy were used to observe the morphology and ultrastructural changes of synaptic dendrites. Immunofluorescence was used to detect the expression of hippocampal synaptic plasticity protein synapsin-1 and postsynaptic density protein 95(PSD-95). Western blot method was used to detect the expression of functional protein synaptophysin(SYP) and synaptic Ras GTPase activating protein(SynGap). The results showed that the rats in the model group had obvious anxiety and depression-like behaviors, the hip-pocampal dendritic spine density and branch length were reduced, the number of synapses was cut, and the internal structure was da-maged. The average fluorescence intensity of synapsin-1 and PSD-95 was significantly reduced and the expression of SYP and SynGap also decreased. High-dose Baihe Dihuang Decoction could significantly improve the anxiety and depression-like behaviors of model rats, relieve synaptic damage, and increase the expression of synapsin-1, PSD-95, SYP, and SynGap proteins. Therefore, we believe that Baihe Dihuang Decoction can improve anxiety and depression behaviors by regulating the synaptic plasticity of hippocampal neurons.

Morfología neuronal en el trastorno del espectro autista / Neuronal morphology in autism spectrum disorder

RESUMEN: El trastorno del espectro autista (TEA) abarca un grupo de trastornos multifactoriales del neurodesarrollo caracterizados por una comunicación e interacción social deteriorada y por comportamientos repetitivos y estereotipados. Múltiples estudios han revelado que en el TEA existen disfunciones sinápticas, en la cual la morfología y función neuronal son sustratos importantes en esta patogenia. En esta revisión comentamos los datos disponibles a nivel de anormalidades neuronales en el TEA, enfatizando la morfología de las dendritas, espinas dendríticas y citoesquelo de actina. Las dendritas y espinas dendríticas, ricas en actina, forman la parte postsináptica de la mayoría de las sinapsis excitadoras. En el TEA, los datos obtenidos apuntan a una desregulación en el crecimiento y desarrollo dendrítico, así como una alteración en la densidad de las espinas dendríticas. Lo anterior, se ve acompañado de alteraciones en la remodelación y composición del citoesqueleto neuronal. Para comprender mejor la fisiopatología del TEA, es necesario mayor información sobre cómo los cambios morfofuncionales de los actores que participan en la sinapsis impactan en los circuitos y el comportamiento.

SUMMARY: Autism Spectrum Disorder (ASD) is a group of multifactorial neurodevelopmental disorders, characterized by impaired communication and social interaction skills, and by repetitive and stereotyped behaviors. Multiple studies report that there are synaptic dysfunctions in ASD, in which important substrates such as morphology and neuronal function are involved in this pathogenesis. In this review we discuss the data available at the level of neuronal abnormalities in ASD, and emphasize the morphological aspects of dendrites, dendritic spines, and actin cytoskeleton. Actin-rich dendrites and dendritic spines shape the postsynaptic part of the most excitatory synapses. In ASD, the data points to a dysregulation in dendritic growth and development, as well as an alteration in the density of dendritic spines. This is accompanied by alterations in the remodeling and composition of the neuronal cytoskeleton. In order to better understand the pathophysiology of ASD, further information is needed on how the elements of synaptic morphofunctional changes impact circuits and behavior.

O desafio para compreender a morfologia cerebral: da visualização à quantificação / Challenges in understanding brain morphology: from visualization to quantification

O objetivo deste trabalho é estudar a morfologia neuronal a partir de modelos animais, fornecer informações biológicas difíceis de serem obtidas em humanos, permitindo estudar condições neuropsiquiátricas como doença de Alzheimer, ansiedade, dentre outras. O presente trabalho descreveu metodologia de estudo para cérebro de roedores, duas técnicas neuroanatômicas, Klüver-Barrera e Golgi-Cox, e seus respectivos processos de quantificação. A técnica de Klüver-Barrera permitiu visualização da substância branca e cinzenta com destaque na bainha de mielina. A técnica de Golgi-Cox, adaptada para realidade de nosso laboratório, mostrou-se eficiente para visualização de neurônios e seus prolongamentos, como dendritos e espinhas dendríticas, permitindo assim a quantificação. A partir de imagens obtidas de microscópio descreveu-se os diferentes passos para quantificação, a determinação de volume de estruturas internas cerebrais (corpo caloso e camada celular do hipocampo) assim como a quantificação das espinhas dendríticas em neurônios piramidais. Os métodos descritos e detalhados poderão ser utilizados em vários campos da neurociência

Neuronal morphology is analyzed in animal models to provide biological information difficult to obtain in humans. The above makes possible the study of neuro-psychiatric, such as Alzheimer´s disease, anxiety and others. Current study described methodology for rodents´ brains, two neuro-anatomic techniques, Klüver-Barrera and Golgi-Cox, and their respective quantification processes. Klüver-Barrera technique visualized the white and gray matter, particularly the myelin sheath. Golgi-Cox technique, adapted for current research, was efficient to visualize neurons and their prolongations, such as dendrites and dendritic spines, with quantification. Images by microscope described the different steps for the quantification, determination of volume of the brain´s internal structures (callous body and the hypocampus´s cell layer) coupled to the quantification of dendritic spines in pyramid neurons. Described and detailed methods will be useful in several fields of neuroscience

Neuronal Remodeling and Dendritic Spines: A Review

The neurons show remodeling in their dendritic arbor and spine/synapsenumber in many brain regions including the hippocampus, amygdala and the prefrontalcortex. The dendritic spine density is reported to be changed due to experiences andstressful conditions. The dendritic spines are the small protrusions arising from thedendritic shaft of the neurons. They have basic shapes as large mushroom spines, shortstubby spines and thin spines. The morphology of spines changes rapidly in response tovarious stimuli that may be internal such as hormones and external such as environmentalchanges. Dendritic spine density plays a major role in classification of principal neuronsi.e. multipolar and pyramidal neurons. The principal neurons may be classified as sparselyspinous, moderately spinous and heavily spinous on the basis of density of spine over thedendritic branches. In response to environment dendritic remodeling takes place in theform of spine shapes, spine turnover and spine density etc. Synaptic plasticity primarilytakes place in dendritic spines and enriched environment have positive effect while socialisolation have negative effect on synapse formation. Exposure of animals to environmentalcomplexity may improve the learning and memory by providing adaptive changes in thedendritic spine density.

Las espinas dendríticas, su función y algunas alteraciones / Dendritic spines, its function and some alterations

Resumen Las espinas dendríticas constituyen modificaciones de la membrana celular de las dendritas, ricas en actina, cuya morfología se modifica y puede sugerir la presencia de alteraciones en la comunicación neuronal. Las espinas dendríticas cuentan con un aparato espinoso que participa en la regulación del calcio (Ca) intracelular. Reportes recientes mencionan la relación entre el número de espinas y las alteraciones del sueño, estado fisiológico en el que ocurre la consolidación de la memoria. Diversos estudios asocian cambios en su forma y densidad con ciertas patologías. En esta revisión se identifican las características morfológicas de estas y su relación con el desarrollo del sistema nervioso, el sueño y algunas patologías.

Abstract The dendritic spines are dendritic membrane modifications rich in actin, whose morphology changes could suggest modifications in neural communication. These dendritic spines have a spiny-apparatus that regulates the intracellular calcium concentration. Recent reports mention the relationship between the number of spines and certain sleep disorders, the physiologic state in which memory consolidation takes place. Changes in their morphology and density are associated with several pathologies. In this revision we describe the morphological modifications of dendritic spines, their relationship with the development of the nervous system, sleep disorders and some other pathologies.

Effect of Electroacupuncture on Learning-memory Ability in Rats with Hypoxic-ischemic Encephalopathy / 针刺研究

OBJECTIVE: To observe the effect of electroacupuncture (EA) on changes of learning-memory ability, psychomotor coordination and anxiety-like behavior of cerebral hypoxic-ischemia (CHI) young rats, so as to explore its protective effect on neurons under hypoxic-ischemic conditions. METHODS: SD rats (aged 7 days) were randomly divided into sham operation (sham, n=12), model (n=11), and EA groups (n=12). In addition, 6 young rats in each group were used for observing the number of dendritic spines after Golgi staining. The CHI model was established by ligation of the left common carotid artery combined with hypoxia in a closed transparent vessel. EA was applied to "Baihui" (GV 20)and "Dazhui" (GV 14) for 20 min, once every other day, for 28 days. The rats' behavior changes were assessed by using rotarod performance (for psychomotor coordination), elevated plus maze (anxiety-like behavior) tests and Morris water maze (learning-memory ability) tests, separately. RESULTS: After modeling, the average escape latency and average escape distance of location navigation test within 70 seconds were significantly increased (P0.05). The density of dendritic spines was significantly lo-wer in the model group than in the sham group (P <0.05), and notably higher in the EA group than in the model group (P<0.05). CONCLUSION: EA can improve the learning-memory ability of CHI young rats, which may be related to its effect in protecting the dendritic spines of CA 1 region of hippocampus from injury.

Mechanism of low-dose ketamine-induced reduction of cognitive dysfunction following sevoflurane anesthesia in aged rats: plasticity of dendritic spines in entorhinal cortical neurons / 中华麻醉学杂志

Objective To investigate the relationship between the plasticity of dendritic spines in entorhinal cortical neurons and mechanism of low-dose ketamine-induced reduction of cognitive dysfunction following sevoflurane anesthesia in aged rats.Methods Thirty-six pathogen-free healthy male SpragueDawley rats,aged 18 months,weighing 500-600 g,were divided into 3 groups (n=12 each) using a random number table:control group (group C),sevoflurane anesthesia group (group Sev) and ketamine group (group K).Group C received no treatment.Group Sev inhaled the mixture of air (flow rate 1 L/min) and 3.6％ sevoflurane for 3 h.In group K,ketamine 10 mg/kg was injected intraperitoneally,and 5 min later the mixture of air (flow rate 1 L/min) and 3.6％ sevoflurane was inhaled for 3 h.Open field test and Morris water maze test were performed 3 days after anesthesia.After the behavioral tests,the animals were sacrificed,and their brains were removed and cut into sections for determination of the density of neurons,density of dendritic spines,and expression of postsynaptic density protein-95 (PSD-95) and synaptophysin (SY38) in superficial laminaes (Ⅱ-Ⅲ) of entorhinal cortex using Nissl's staining,Golgi staining and immunohistochemistry,respectively.Results Compared with group C,the time of staying at the central region was significantly shortened,the escape latency was prolonged,the density of dendritic spines was decreased,and the expression of PSD-95 and SY38 was down-regulated in group Sev (P＜0.05).Compared with group Sev,the time of staying at the central region was significantly prolonged,the escape latency was shortened,the density of dendritic spines was increased,and the expression of PSD-95 and SY38 was upregulated in group K (P＜0.05).There were no significant differences in the density of neurons in entorhinal cortex between the three groups (P＞0.05).Conclusion The mechanism by which low-dose ketamine attenuates cognitive dysfunction induced by sevoflurane anesthesia may be related to the enhanced plasticity of dendritic spines in entorhinal cortical neurons of aged rats.

Effect of the Chinese Prescription "Bushen Huatan Yizhi"on Learning and Memory Ability of Rat Model of Alzheimer's Disease / 华中科技大学学报(医学版)

Objective "Bushen Huatan Yizhi"is a Chinese prescription that can replenish the kidney,remove phlegm and improve intelligence.This study was aimed to examine the efficacy of "Bushen Huatan Yizhi"in the rat model of Alzheimer's disease(AD)and the underlying mechanism.Methods The model of AD was established through injection of β-amyloid pro-tein25-35 (Aβ25-35 )into the left lateral ventricles of Sprague Dawley(SD)rats.Animals were treated with low(12.5 g/kg),medium (25 g/kg)or high(50 g/kg)dose of "Bushen Huatan Yizhi"decotion,twice daily,by gavage.Four weeks later,the Morris water maze and Golgi staining were used to detect the ability of learning and memory and the number of dendritic spines,and Western blotting to measure the levels of N-methyl-D-aspartatic acid receptor1(NR1),subunit 2B(NR2B)and syntaxin in the left hippo-campus.Results Injection of β-amyloid protein25-35 (Aβ25-35 )into the left lateral ventricle of rat could reduce the learning and memory ability of AD rats,which was accompanied by the decrease in the number of dendritic spines and the level of NR2B.These effects could be reversed by addition of "Bushen Huatan Yizhi"at a moderate dose.Conclusion "Bushen Huatan Yizhi"protects against the learning and memory decline of AD rats,possiblely by increasing the number of dendritic spines,reg-ulating their pasticity and upregulating the NR2B level.

MiR-130a regulates neurite outgrowth and dendritic spine density by targeting MeCP2

MicroRNAs (miRNAs) are critical for both development and function of the central nervous system. Significant evidence suggests that abnormal expression of miRNAs is associated with neurodevelopmental disorders. MeCP2 protein is an epigenetic regulator repressing or activating gene transcription by binding to methylated DNA. Both loss-of-function and gain-of-function mutations in the MECP2 gene lead to neurodevelopmental disorders such as Rett syndrome, autism and MECP2 duplication syndrome. In this study, we demonstrate that miR-130a inhibits neurite outgrowth and reduces dendritic spine density as well as dendritic complexity. Bioinformatics analyses, cell cultures and biochemical experiments indicate that miR-130a targets MECP2 and down-regulates MeCP2 protein expression. Furthermore, expression of the wild-type MeCP2, but not a loss-of-function mutant, rescues the miR-130a-induced phenotype. Our study uncovers the MECP2 gene as a previous unknown target for miR-130a, supporting that miR-130a may play a role in neurodevelopment by regulating MeCP2. Together with data from other groups, our work suggests that a feedback regulatory mechanism involving both miR-130a and MeCP2 may serve to ensure their appropriate expression and function in neural development.

Quick Golgi method: Modified for high clarity and better neuronal anatomy.

The Golgi methods have long been used to study the neuronal soma, axons, dendritic arborization and spines. The major concerns of the Golgi method have been its unpredictable nature (inconsistency of impregnation of the stain), time consumed, tissue hardening and clear background, resulting in several modifications to improve the cellular visualization. In the present work we describe a modification of the rapid-Golgi method that takes the benefit of perfusion fixation (with rapid-Golgi solution) then post-fixation in the same fixative for 36 h followed by 36 h impregnation in aqueous AgNO3 followed by vibratomy. This modification is simpler, faster and inexpensive, provides a consistent staining of neurons with good resolution of neuronal soma, dendritic arborization as well as spines with much reduced formation of silver chromate crystals and background in just 3 days.

Progress of dendritic spines in the nervous system diseases / 国际儿科学杂志

Dendritic spines are functional protrusions on neuron dendrites and formation of excitatory synaptic sites.Dendritic spines contain a variety of cell surface receptors,actin cytoskeleton,scaffolding proteins and other components,which regulate the growth of dendritic spines maturation and structure.Multiple components within dendritic spines not only have effects on expression of its shape and structure,but also on the function.Morphology of dendritic spines is closely related with its function.Its shape is affected by many factors in the changing process.So dendritic spine plasticity is an important aspect of synaptic function in the central nervous system,and is closely related with learning and memory function and central nervous system diseases.

Effects of ischemic postconditioning on neuron structure plasticity and memory after global cerebral ischemia injury in rats / 中华创伤杂志

Objective To observe the effect of ischemic postconditioning on neuron structure plasticity and memory after global cerebral ischemia injury in rats and discuss the protection mechanism from aspect of Morphology. Methods A total of 36 SD male rats were randomly divided into sham operation group, global cerebral ischemia for 15 min group and global cerebral ischemia plus postconditioning group, 12 rats per group. The pullsinelli 4 vessel occlusion was applied to produce the models of global cerebral ischemia reperfusion injury, common carotid arteries (CCA) occlusion with 15 min and postconditioning with three cycles, of 15 sec release and 15 sec occlusion (15s/15s). Six rats from each group were evaluated by Morris Maze test for the ability of space learning and memory and the other six rats were evaluated by golgi stain for morphologic change of neuron. Results The ischemic postcondtioning group showed significant shorter mean escape latency compared with the sham operated group ( at day 3, P =0. 014; at day 4, P =0.040; at day 5, P =0.001 ). The density of dendritic spine in ischemic postcondtioning group was increased more significantly compared with ischemic group ( F = 562. 820,P ＜ 0. 01 ). Conclusion Ischemic postconditioning has obvious protective effect on cerebral ischemiainduced memory impairment, which may be related to alleviation of dendritic spine injury.