Electroacupuncture inhibits dendritic spine remodeling through the srGAP3-Rac1 signaling pathway in rats with SNL

Previous studies have shown that peripheral nerve injury can lead to abnormal dendritic spine remodeling in spinal dorsal horn neurons. Inhibition of abnormal dendritic spine remodeling can relieve neuropathic pain. Electroacupuncture (EA) has a beneficial effect on the treatment of neuropathic pain, but the specific mechanism remains unclear. Evidence has shown that slit-robo GTPase activating protein 3 (srGAP3) and Rho GTPase (Rac1) play very important roles in dendritic spine remodeling. Here, we used srGAP3 siRNA and Rac1 activator CN04 to confirm the relationship between SrGAP3 and Rac1 and their roles in improving neuropathic pain with EA. Spinal nerve ligation (SNL) was used as the experimental model, and thermal withdrawal latency (TWL), mechanical withdrawal threshold (MWT), Western blotting, immunohistochemistry and Golgi-Cox staining were used to examine changes in behavioral performance, protein expression and dendritic spines. More dendritic spines and higher expression levels of srGAP3 were found in the initial phase of neuropathic pain. During the maintenance phase, dendritic spines were more mature, which was consistent with lower expression levels of srGAP3 and higher expression levels of Rac1-GTP. EA during the maintenance phase reduced the density and maturity of dendritic spines of rats with SNL, increased the levels of srGAP3 and reduced the levels of Rac1-GTP, while srGAP3 siRNA and CN04 reversed the therapeutic effects of EA. These results suggest that dendritic spines have different manifestations in different stages of neuropathic pain and that EA may inhibit the abnormal dendritic spine remodeling by regulating the srGAP3/Rac1 signaling pathway to alleviate neuropathic pain.

Effects of ICG-001 on autistic behaviors and the development of hippocampal dendritic spine morphology in rats / 中华实用儿科临床杂志

Objective:To explore the effects of the compound ICG-001 on autism-like behaviors and the morphological development of dendritic spines in hippocampal pyramidal neurons of rats.Methods:Healthy Wistar rats were mated.The offspring were divided into the saline-treated group, ICG-001 control group, Sodium valproate (VPA) group and ICG-001 treatment group by using the random number table method.Each group had 12 rats.Social interaction, repetitive, compulsive and anxiety-like behaviors in rodents were assessed by three-chambered social approach, marble burying, open-field and elevated plus maze tests.The number of neuronal nuclei (NeuN)-positive neurons in the hippocampal CA1 region was calculated by the immunofluorescence method.Golgi staining was carried out to detect the density and morphological changes of dendritic spines in hippocampal pyramidal neurons of rats.The expression of phosphorylated LIM kinase 1(LIMK1), phosphorylated actin binding protein(Cofilin), fibros actin (F-actin) and developmentally-regulated brain protein A (Drebrin A) was examined by Western blot.The univariate analysis was made to examine whether the difference was statistically significant, and the data between groups were compared by the Tukey method. Results:(1) In the three-chambered social approach test, the rats in the saline-treated group, ICG-001 control group, VPA group and ICG-001 treatment group spent (219.42±5.38) s, (218.67±10.12) s, (126.58±5.02) s, and (218.58±6.63) s in the chamber, respectively.The corresponding preference score of the said 4 groups were 0.43±0.05, 0.43±0.04, 0.22±0.01 and 0.42±0.04, respectively.Compared with the VPA group, the ICG-001 treatment group spent longer time in the chamber and had a higher preference score (all P<0.05). (2) In the marble burying experiment, the number of marbles buried in said 4 groups were 9.13±0.52, 9.08±0.64, 15.13±0.82 and 9.42±0.86, respectively.ICG-001-treated rats buried markedly less marbles than VPA-exposed rats ( P<0.05). (3) In the open-field test, the rats in the said 4 groups spent (82.33±1.83) s, (81.32±4.19) s, (45.51±3.02) s and (81.44±3.19) s in the center area, respectively.Administration of ICG-001 significantly increased the time that VPA-exposed rats spent in the center area ( P<0.05). (4)In the elevated plus maze trial, the rats in the said 4 groups spent (107.75±7.23) s, (106.08±7.50) s, (63.42±1.91) s and (106.67±7.07) s in open arms, respectively.ICG-001 treatment notably increased the time that VPA-exposed rats spent in open arms ( P<0.05). (5) Immunofluorescence analysis results revealed that the number of NeuN-positive cells in the hippocampal CA1 region of said 4 groups was (41.83±1.17)×10 4/μm 2, (41.00±0.77)×10 4/μm 2, (27.17±0.95)×10 4/μm 2 and (40.00±0.90)×10 4/μm 2, respectively.ICG-001 treatment normalized the alteration in the number of NeuN-containing neurons in VPA-exposed rats ( P<0.05). (6) Golgi staining showed that the density of dendritic spines in hippocampal CA1 pyramidal neurons of said 4 groups was (0.74±0.04)/μm, (0.73±0.03)/μm, (0.49±0.03)/μm and (0.70±0.02) /μm, respectively.Of all types of dendritic spines, mushroom spines accounted for (0.49±0.02)%, (0.49±0.02)%, (0.33±0.02)% and (0.43±0.02) % in said 4 groups.Thin spines accounted for (0.27±0.02)%, (0.26±0.02)%, (0.34±0.01)% and (0.26±0.01) % in said 4 groups, respectively.Compared with the VPA group, the ICG-001 treatment group showed a significant increase in the density of dendritic spines in hippocampal CA1 pyramidal neurons ( P<0.05). After ICG-001 treatment, the number of mushroom spines greatly increased and the number of thin spines sharply decreased in VPA-exposed rats (all P<0.05). (7) According to Western blot test results, the phosphorylated LIMK1/LIMK1 ratio of the hippocampus in said 4 groups were 100.33±2.30, 99.34±2.28, 57.76±4.10 and 99.13±1.90, respectively.The phosphorylated Cofilin /Cofilin ratio were 100.18±2.43, 100.18±1.70, 57.12±1.88 and 99.53±1.69, respectively.The F-actin/globular actin(G-actin) ratio were 100.07±0.86, 99.99±1.72, 51.19±1.23 and 99.28±3.17, respectively.The expression level of Drebrin A were 100.79±1.19, 100.12±2.04, 52.86±3.26 and 99.97±2.44, respectively.Administration of ICG-001 effectively prevented the decrease of phosphorylated LIMK1, phosphorylated Cofilin, F-actin and Drebrin A in the hippocampus of VPA-exposed rats (all P<0.05). Conclusions:ICG-001 regulates the LIMK1/Cofilin signaling pathway, promotes the generation of F-actin, increases the expression of Drebrin A, and thereby alleviates autistic-associated symptoms.

Neuronal Histone Methyltransferase EZH2 Regulates Neuronal Morphogenesis, Synaptic Plasticity, and Cognitive Behavior in Mice / 神经科学通报·英文版

The histone methyltransferase enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2)-mediated trimethylation of histone H3 lysine 27 (H3K27me3) regulates neural stem cell proliferation and fate specificity through silencing different gene sets in the central nervous system. Here, we explored the function of EZH2 in early post-mitotic neurons by generating a neuron-specific Ezh2 conditional knockout mouse line. The results showed that a lack of neuronal EZH2 led to delayed neuronal migration, more complex dendritic arborization, and increased dendritic spine density. Transcriptome analysis revealed that neuronal EZH2-regulated genes are related to neuronal morphogenesis. In particular, the gene encoding p21-activated kinase 3 (Pak3) was identified as a target gene suppressed by EZH2 and H3K27me3, and expression of the dominant negative Pak3 reversed Ezh2 knockout-induced higher dendritic spine density. Finally, the lack of neuronal EZH2 resulted in impaired memory behaviors in adult mice. Our results demonstrated that neuronal EZH2 acts to control multiple steps of neuronal morphogenesis during development, and has long-lasting effects on cognitive function in adult mice.

Research progress on the structural plasticity of neurons in the visual cortex / 中华实验眼科杂志

During the development of visual cortex, the structure of neurons will adaptively change and adjust according to the changes of external environment, which shows structural plasticity.The experience-dependent plasticity of visual cortex is based on the structural changes of neurons, which mainly include change of synaptic connections, disappearance or increase of dendritic spines, turnover of dendritic spines, changes in the size of dendritic spines, changes in postsynaptic density and alterations of perineuronal nets.The structural changes of neurons have significant influence on the plasticity of visual cortex function and structure, and are highly associated with some molecules or non-neuronal components such as paired immunoglobulin-like receptor B, Ly-6/neurotoxin-like protein 1, Nogo, microglia and extracellular matrix and so on.In addition, external intervention factors such as abnormal visual experience and environmental enrichment can have significant impact on the regulation of the structural changes of neurons, and finally influence the development of visual function and the recovery from visual impairment.In comparison with the functional studies, studies on the structural plasticity of visual cortical neurons depend on the state-of-the-art imaging techniques at cellular or sub-cellular level with more visualizable and convincing results.The constant exploration of the structural plasticity of visual cortex will enhance our understanding of visual development-related diseases, such as amblyopia, and lay the foundation for related basic research and innovative treatments.Advances in the structural plasticity of visual cortex were reviewed in this article.

Mechanism of valproic acid-induced dendritic spine and synaptic impairment in the prefrontal cortex for causing core autistic symptoms in mice / 南方医科大学学报

OBJECTIVE@#To investigate the mechanism of valproic acid (VPA) -induced impairment of the dendritic spines and synapses in the prefrontal cortex (PFC) for causing core symptoms of autism spectrum disorder (ASD) in mice.@*METHODS@#Female C57 mice were subjected to injections of saline or VPA on gestational days 10 and 12, and the male offspring mice in the two groups were used as the normal control group and ASD model group (n=10), respectively. Another 20 male mice with fetal exposure to VPA were randomized into two groups for stereotactic injection of DMSO or Wortmannin into the PFC (n=10). Open field test, juvenile play test and 3-chamber test were used to evaluate autistic behaviors of the mice. The density of dendrite spines in the PFC was observed with Golgi staining. Western blotting and immunofluorescence staining were used to detect the expressions of p-PI3K, PI3K, p-AKT, AKT, p-mTOR, mTOR and the synaptic proteins PSD95, p-Syn, and Syn in the PFC of the mice.@*RESULTS@#Compared with the normal control mice, the mice with fetal exposure to VPA exhibited obvious autism-like behaviors with significantly decreased density of total, mushroom and stubby dendritic spines (P < 0.05) and increased filopodia dendritic spines (P < 0.05) in the PFC. The VPA-exposed mice also showed significantly increased expressions of p-PI3K/PI3K, p-AKT/AKT, and p-mTOR/mTOR (P < 0.01) and lowered expressions of PSD95 and p-Syn/Syn in the PFC (P < 0.05 or 0.001). Wortmannin injection into the PFC obviously improved the ASD-like phenotype and dendritic spine development, down-regulated PI3K/Akt/mTOR signaling pathway and up-regulated the synaptic proteins in VPA-exposed mice.@*CONCLUSION@#In male mice with fetal exposure to VPA, excessive activation of PI3K/Akt/mTOR signaling pathway and decreased expressions of the synaptic proteins PSD95 and p-Syn cause dendritic spine damage and synaptic development disturbance in the PFC, which eventually leads to ASD-like phenotype.

Multiple Mild Stimulations Reduce Membrane Distribution of CX3CR1 Promoted by Annexin a1 in Microglia to Attenuate Excessive Dendritic Spine Pruning and Cognitive Deficits Caused by a Transient Ischemic Attack in Mice / 神经科学通报·英文版

A transient ischemic attack (TIA) can cause reversible and delayed impairment of cognition, but the specific mechanisms are still unclear. Annexin a1 (ANXA1) is a phospholipid-binding protein. Here, we confirmed that cognition and hippocampal synapses were impaired in TIA-treated mice, and this could be rescued by multiple mild stimulations (MMS). TIA promoted the interaction of ANXA1 and CX3CR1, increased the membrane distribution of CX3CR1 in microglia, and thus enhanced the CX3CR1 and CX3CL1 interaction. These phenomena induced by TIA could be reversed by MMS. Meanwhile, the CX3CR1 membrane distribution and CX3CR1-CX3CL1 interaction were upregulated in primary cultured microglia overexpressing ANXA1, and the spine density was significantly reduced in co-cultured microglia overexpressing ANXA1 and neurons. Moreover, ANXA1 overexpression in microglia abolished the protection of MMS after TIA. Collectively, our study provides a potential strategy for treating the delayed synaptic injury caused by TIA.

Cranial irradiation alters dendritic spine density and morphology in the young rat hippocampus / 中华放射医学与防护杂志

Objective:To explore the changes of dendritic spine morphology and structure in dentate gyrus(DG) and CA1 areas of hippocampus of young rats, so as to provide a direct morphological basis for studying the molecular mechanism of radiation cognitive impairment.Methods:21-day-old Sprague-Dawley (SD) rats were given a single dose of 10 Gy whole brain irradiation. The changes of cognitive function, dendritic spine density and morphological changes in DG and CA1 areas of hippocampus were observed 1 and 3 months after irradiation, and the expression of postsynaptic density protein (PSD95) was detected by Western blot.Results:The cognitive impairment was observed in young rats 3 months after irradiation. The density of dendritic spines in DG area of hippocampus was decreased significantly by 39.06% and 29.27% at 1 and 3 months after irradiation ( t=14.96, 12.35, P<0.05), respectively. The density of dendritic spines in the basal dendrites of hippocampal CA1 area was decreased by 33.40% ( t=10.39, P<0.05) 1 month after irradiation, but had no significant change at 3 months after irradiation. While the density of dendritic spines in the apical dendrites of CA1 region did not change significantly at 1 and 3 months after irradiation. In addition, the morphology of dendritic spines in DG and CA1 regions of hippocampus was dynamically changed after irradiation. The expression of PSD95 protein was decreased by 24.6% and 50.5% ( t=2.97, 9.27, P<0.05) at 1 and 3 months after irradiation, respectively. Conclusions:This study reported the density and morphological changes of dendritic spines in different brain regions of hippocampus of young rats after ionizing radiation, suggesting that PSD95 may participate in the occurrence of radiation-induced cognitive impairment by affecting the structure and morphology of dendritic spines and reducing synaptic plasticity.

Rac1 Modulates Excitatory Synaptic Transmission in Mouse Retinal Ganglion Cells / 神经科学通报·英文版

Ras-related C3 botulinum toxin substrate 1 (Rac1), a member of the Rho GTPase family which plays important roles in dendritic spine morphology and plasticity, is a key regulator of cytoskeletal reorganization in dendrites and spines. Here, we investigated whether and how Rac1 modulates synaptic transmission in mouse retinal ganglion cells (RGCs) using selective conditional knockout of Rac1 (Rac1-cKO). Rac1-cKO significantly reduced the frequency of AMPA receptor-mediated miniature excitatory postsynaptic currents, while glycine/GABA receptor-mediated miniature inhibitory postsynaptic currents were not affected. Although the total GluA1 protein level was increased in Rac1-cKO mice, its expression in the membrane component was unchanged. Rac1-cKO did not affect spine-like branch density in single dendrites, but significantly reduced the dendritic complexity, which resulted in a decrease in the total number of dendritic spine-like branches. These results suggest that Rac1 selectively affects excitatory synaptic transmission in RGCs by modulating dendritic complexity.

Effect of lipopolysaccharide-mediated infection during pregnancy on the expression of mineralocorticoid receptor and dendritic spines in hippocampus of rat offspring / 中华实用儿科临床杂志

Objective To observe the effect of lipopolysaccharide (LPS)-mediated infection during pregnancy on the expression of mineralocorticoid receptor (MR) and density of dendritic spines in CA1 region of the dorsal hippocampus of rat offspring,so as to explore the mechanisms for learning and memory injury of rat offspring which were infected during prenatal period,then to provide scientific experimental evidence for the prevention of prenatal infection-induced delayed neuropsychiatric sequelae which contributed to learning and memory dysfunction.Methods Ten-week-old female Sprague-Dawley rats (n =30) were matched with male rats (1 ∶ 1).Pregnant rats were randomly divided into a control group (n =10) and an experimental group (n =20).The pregnant rats in experimental group were treated with LPS (66 μg/kg,intraperitoneally),and the pregnant rats in control group were intraperitoneally injected with same volume of saline on gestational day 10.On postnatal day 48,Morris water maze was used to estimate the ability of learning and memory;the brain tissues of offspring were taken and paraffin sections were stained with hematoxylin eosin (HE) for histological observation of CA1 region of the dorsal hippocampus;frozen sections were treated with indirect immunofluorescence to observe the expression of MR in CA1 region of the dorsal hippocampus;Golgi-Cox method was used to observe the density of dendritic spines of CA1 region.Results In Morris water maze test,from the third day the time of escape latency in experimental group [the 3rd day:(42.603 ± 9.837) s;the 4th day:(30.222 ± 9.789) s;the 5th day:(28.808 ± 12.526) s] was significantly higher than that of the control group [the 3rd day:(28.078±14.088) s;the 4th day:(20.692±13.099) s;the 5th day:(14.632 ±11.624) s] (the 3rd day:t =-3.274,P＜0.01;the 4th day:t =-2.257,P ＜0.05;the 5th day:t =-3.213,P＜0.01);the swimming time in the target quadrant [(14.660 ± 7.337) times] and the number of crossing platform [(0.933 ± 0.704) times] in experi mental group were significantly decreased compared with those of the control group [time:(23.820 ± 6.321) s;num bers:(2.000 ± 0.756) times] (t =3.663,4.000,all P ＜ 0.01).Hematoxylin eosin staining showed that the nerve cells of the hippocampus in the control group distributed in order,nucleuses were round or oval,nucleoli were obvious,and chromatins were homogeneous;but the cells in the experimental group distributed in disorder and pathological changes were detected,such as cellular swelling,necrosis and obvious nuclear pyknosis.By immunofluorescence staining,the average optical density (AOD) of MR in CA1 region decreased significantly in the experimental group (0.067 ± 0.017) compared with that of the control group (0.083 ± 0.009) (t =2.644,P ＜ 0.05).In Golgi-Cox method,the density of dendritic spines in experimental group [(7.705 ± 0.791)/10 μm] was below that of the control group [(9.655 ± 1.391)/10 μm] (t =3.852,P ＜ 0.01).Conclusions LPS-mediated infection during pregnancy might lead to hippocampus-dependent learning and memory dysfunction which might be associated with the reduced expression of MR and the low density of dendritic spines in CA1 region of the dorsal hippocampus.

Influence of pregnant rats' prenatal chronic stress on hippocampal dendritic spines and the function of learning and memory in their offsprings / 中华实用儿科临床杂志

Objective To study the influence of pregnant rats' prenatal chronic stress (PS) on learning and memory of their offspring rats and its possible molecular mechanisms.Methods Pregnant females were individually restrained for 45 min 3 times a day during pregnancy from day 14 to day 21.Control pregnant females were left undisturbed in their home cages.The rat offsprings were randomly assigned to PS group or control group.Males and females were kept for the study separately.The learning and memory of the developing rat offspring in the Morris water maze were examined.The basal levels of corticosterone (COR) and adreno-cortico-tropic-hormone (ACTH) were analyzed by using radioimmunoassay.The Golgi-Cox impregnation technique was used to compare density and morphology of the CA1 hippocampal dendritic spines.Results The escape latency (EL) to find the platform in the control group was significantly less than that in the PS group in female rat offspring (F =4.533,P ＜ 0.05),and the difference was statistically significant on the 5th day (t =2.788,P ＜ 0.01).EL to find the platform in the control group was significantly less than that in the PS group in male rat offspring (F =6.101,P ＜0.05),and the difference was statistically significant on the second day (t =3.051,P ＜ 0.01).In the space exploration experiments of the water maze,the retention time observed for the control group and the PS group in the goal quadrant was similar(P ＞ 0.05).The basal levels of the serum COR in the PS group were higher than those in the control group of female rat offspring(t =3.658,P ＜ 0.01) and the basal levels of the serum ACTH in the PS group were higher than those in the control group of male rat offsprings(t =2.319,P ＜ 0.05).A simplified pattern was observed in the CA1 hippocampal dendritic spines in the PS group,showing a less extent of dendritic arborization and the density was significantly lower than that in the control group(t =-3.072,P ＜ 0.01).Conclusions Altered function of the hypothalamic-pituitary-adrenal axis in the offspring mediates the cognitive alterations observed following prenatal stress should to be associated with the lower density and simplified pattern of CA1 dendritic spines.

High-fat diet induces learning and memory impairments and hippocampal dendritic spine density in rats / 中华行为医学与脑科学杂志

Objective To explore the influence of high fat diet on learning and memory,as well as the alteration of the number of neurons and morphology of dendritic spines in rat hippocampi.Methods 24 male adult SD rats were randomly assigned to high fat diet group or control group.The rats were fed with high-fat diet or standaM laboratory rodent chow diet for 12 weeks.Learning and memory were tested by Morris water maze and object recognition tests, and mood and motor ability were tested by open field tests.Golgi staining detected dendritic spine density of hippocampal neurons, and Nissl staining was used to observe the number of hippocampal neurons and pathological changes.Results High-fat diet induced rat spatial learning deficits, which was demonstrated by the prolonged escape latency ((38.50±9.70) s, (20.08±7.35) s, (19.96± 10.56) s, (22.75± 12.51) s, (14.56±4.82) s) compared with the control ((33.61±12.41) s, (14.25±7.89) s, (15.06±7.59) s, (5.53±2.81) s, (4.7± 1.58) s).The spatial memory deficits demonstrated that the latency reaching platform ((30.46± 21.43) s) was prolonged compared with control ((5.18± 1.33)s).The working memory was impaired, which was demonstrated by the prolonged escape latency compared with control group (P＜ 0.05).Discrimination index lowered than control group ((0.67±0.12) vs (0.81±0.08)), and the difference was significant (P=0.038), but no anxiety behaviors were observed(P=0.461).The neuron number of hippocampal neurons and dendritic spine density were significantly lowered than those in the control group((209.73±24.29) vs (262.2±18.94), (17.9±2.84) vs (21.93±2.56) ,respectively) (P＜0.05).Conclusion Intake of high-fat diet can impair learning and memory in rats, as well as decrease the number of neurons and the density of dendritic spines in the hippocampus.

Effects ofZi-Bu Pi-YinRecipe on Dendritic Spines in Spleen-YinDeficiency Dementia Model Rats / 世界科学技术-中医药现代化

This study was aimed to observe the changes of dendritic spine density in different regions of brain among spleen-yindeficiency dementia (SYDD) model rats, in order to investigate the effects ofZi-Bu Pi-Yin Recipe (ZBPYR) on dendritic spines. Spleen-yindeficiency (SYD) rats were modeled by classical method. And incubatedβ-Amyloid 1-40 (Aβ1-40) was injected into the hippocampus of each rat to make SYDD model, which received the administration of ZBPYR. Golgi staining was used to stain dendritic spine in different regions of brain in rat model for the observation of the amount and shape. The results showed that dendritic spine density in different regions of hippocampus and cortex in SYDD group was reduced than that of the SYD group. Compared with the dementia group and the SYDD group, the dendritic spine density in different regions of hippocampus and cortex of the SYDD + ZBPYR group was increased. Compared with the blank control group, the dendritic spine density in different regions of hippocampus and cortex in rats from the dementia group was reduced. It was concluded that there were different degrees of reducing in the dendritic spine density of different brain regions in SYDD group. ZBPYR improved the learning and memory impairment, which might be related to the maintenance of dendritic spine density in different brain regions.

Developmental bisphenol-A exposure affects hippocampal dentate gyrus area spine formation through Wnt/β-catenin signaling / 中国药理学与毒理学杂志

OBJECTIVE To investigate the effects and its underlying mechanis m of bisphenol-A (BPA)exposure on spine and synapse formation in detate gyrus (DG)area of hippoca mpus during criti-cal develop mental period.METHODS Sprague-Dawley(SD)rats were injected intraperitoneally with BPA (50,250 and 500 μg·kg -1·d -1 )fro m postnatal day 7 (PND7)to PND14.Dendritic spine morphol-ogy in DG area was exa mined using Golgi-Cox staining method and determined with I mage J software. Western blotting method was e mployed to test the Wnt related proteins.RESULTS The spine density and the average spine head size in BPA exposed groups significantly decreased in a dose-dependent manner when co mpared to control group(P<0.05).Meanwhile,Wnt related proteins were affected dur-ing BPA exposure.Specifically,the percentage of phosphorylated β-catenin increased following BPA ex-posure (P<0.05),whereas Wnt7a expression level was significantly decreased and Wnt5a expression level increased (P<0.05).CONCLUSION Wnt signaling pathway plays an i mportant role in BPA-in-duced i mpairments in spine and synapse formation.

Depressed nNOS expression during spine transition in the developing hippocampus of FMR1 KO mice

Nitric oxide (NO), synthesized as needed by NO synthase (NOS), is involved in spinogenesis and synaptogenesis. Immature spine morphology is characteristic of fragile X syndrome (FXS). The objective of this research was to investigate and compare changes of postnatal neuronal NOS (nNOS) expression in the hippocampus of male fragile X mental retardation 1 gene knockout mice (FMR1 KO mice, the animal model of FXS) and male wild-type mice (WT) at postnatal day 7 (P7), P14, P21, and P28. nNOS mRNA levels were analyzed by real-time quantitative PCR (N = 4-7) and nNOS protein was estimated by Western blot (N = 3) and immunohistochemistry (N = 1). In the PCR assessment, primers 5’-GTGGCCATCGTGTCCTACCATAC-3’ and 5’-GTTTCGAGGCAGGTGGAAGCTA-3’ were used for the detection of nNOS and primers 5’-CCGTTTCTCCTGGCTCAGTTTA-3’ and 5’-CCCCAATACCACATCATCCAT-3’ were used for the detection of β-actin. Compared to the WT group, nNOS mRNA expression was significantly decreased in FMR1 KO mice at P21 (KO: 0.2857 ± 0.0150, WT: 0.5646 ± 0.0657; P < 0.05). Consistently, nNOS immunoreactivity also revealed reduced staining intensity at P21 in the FMR1 KO group. Western blot analysis validated the immunostaining results by demonstrating a significant reduction in nNOS protein levels in the FMR1 KO group compared to the WT group at P21 (KO: 0.3015 ± 0.0897, WT: 1.7542 ± 0.5455; P < 0.05). These results suggest that nNOS was involved in the postnatal development of the hippocampus in FXS and impaired NO production may retard spine maturation in FXS.

Differential regulation of Purkinje cell dendritic spines in rolling mouse Nagoya (tg(rol)/tg(rol)), P/Q type calcium channel (alpha1(A)/Ca(v)2.1) mutant / 대한해부학회지

Voltage dependent calcium channels (VDCC) participate in regulation of neuronal Ca2+. The Rolling mouse Nagoya (Cacna1a(tg-rol) ) is a spontaneous P/Q type VDCC mutant, which has been suggested as an animal model for some human neurological diseases such as autosomal dominant cerebellar ataxia (SCA6), familial hemiplegic migraine and episodic ataxia type-2. Morphology of Purkinje cell (PC) dendritic spine is suggested to be regulated by signal molecules such as Ca2+ and by interactions with afferent inputs. The amplitude of excitatory postsynaptic current was decreased in parallel fiber (PF) to PC synapses, whereas apparently increased in climbing fiber (CF) to PC synapses in rolling mice Nagoya. We have studied synaptic morphology changes in cerebella of this mutant strain. We previously found altered synapses between PF varicosity and PC dendritic spines. To study dendritic spine plasticity of PC in the condition of insufficient P/Q type VDCC function, we used high voltage electron microscopy (HVEM). We measured the density and length of PC dendritic spines at tertiary braches. We observed statistically a significant decrease in spine density as well as shorter spine length in rolling mice compared to wild type mice at tertiary dendritic braches. In proximal PC dendrites, however, there were more numerous dendritic spines in rolling mice Nagoya. The differential regulation of rolling PC spines at tertiary and proximal dendrites in rolling mice Nagoya suggests that two major excitatory afferent systems may be regulated reciprocally in the cerebellum of rolling mouse Nagoya.

The Experimental Study of the Effects of Different Swimming Load Training on Rat Brain Morphology / 中国运动医学杂志

Under the different load of training stimulating, the changes in center nervous system of rat were observed.This experimental training intensities included normal -load and over-load using a swimming pool with circular water flow in order to investigate the effects on the neuron size and the density of dendritic spine of the large pyramidal cells in layer Ⅴ in motor areas of cerebral cortex.This study lead to the following conclusions:the size of nucleus and nucleolus and the density of spines of apical dendrites, insidal dendrites and basal dendrites of large pyramidal cells in layer Ⅴ in motor areas of cerebral cortex of normal-load and over-load group were higher than those of control group.It improve the capacity of brain in information processing.

ULTRASTRUCTURE OF THE SPINE APPARATUS IN CEREBRAL CORTEX / 解剖学报

273 spine apparatus were observed under electron microscope. The results were as follows: 1.The flat-type sac of 5 types of the sac which constituted the spine apparatus covered the majority. Most of them were arranged parallelly and a few dispersively. The horseshoe or braid shaped arrangement was also seen in some cases. 2.The number of the sac varied from 3 to 6 in most of the cases, and a few over 10. Sometimes 2 or 3 spine apparatus can be seen within a single dendritic spine. 3.The spine apparatus often locates in the dendritic spine. In some cases the spine apparatus can be seen within the dendrites or in the juncture of dendritic trunk and dendritic spine 4.The morphological structure of the dense bands is comparatively complex. Most of the bends are narrow, some are broad, fine granular or mist-like in shape. The dense bends are located in between the adjacent sacs mostly and in few cases on one side of the spine apparatus. In some cases, one end of the dense band is fused with the sac.

MALE-FEMALE DIFFERENCE IN CYTOARCHITECTURE OF THE SEXUALLY DIMORPHIC NUCLEUS OF THE PREOPTIC AREA IN RATS / 解剖学报

The cytoarchitecture of the sexually dimorphic nucleus of the preoptic area(SDN-POA)of male and female rats was studied with Nissl stain and rapid Golgimethod under light microscope.The results were as follows:1.The volume of theSDN-POA of the male was markedly 3.1 times larger than that of the female.2.In both sexes,the cell density of the SDN-POA significantly increased as comparedwith that of the surrounding,while the sexual difference of the cell density withinthe SDN-POA was not found.3.There was marked male-female difference in theneu(?)onal organization of the nucleus,in which the number of large cells was signi-ficantly greater in males than in females.4.In males,dendritic trees principallyoriented in dorsolateral,ventrolateral and medial directions.In contrast,dendritictrees in females mainly oriented in dorsal and ventromedial directions.5.The meantotal length of the dendritic tree was larger in males than in females and the dis-tribution of the dendritic tree showed sexual difference in the X axis but not in theY axis.6.The number of the dendritic spine was 2.1 times greater in females thanin males.