Activin A maintains cerebral cortex neuronal survival and increases voltage-gated Na^+ neuronal current

Activin A, which was first described in 1986, has been shown to maintain hippocampal neuronal survival. Activin A increases intracellular free Ca2＋ via L-type Ca2＋ channels. Our previous study showed that activin A promotes neurite growth of dorsal root ganglia in embryonic chickens and inhibits nitric oxide secretion. The present study demonstrated for the first time that activin A could maintain cerebral cortex neuronal survival in vitro for a long period, and that activin A was shown to increase voltage-gated Na＋ current （/Na） in Neuro-2a cells, which was recorded by patch clamp technique. The present study revealed a novel mechanism for activin A, as well as the influence of activin A on neurons by regulating expressions of vasoactive intestine peptide and inducible nitric oxide synthase.

Protective estrogen-like properties and mechanism of quercetin in rat cerebral cortex neurons

OBJECTIVE To investigate the effect of quercetin on primary cultured newborn rat cortex neuron cell which is estrogen depletion,and discuss the possible mechanism,to provide new ideas and strategies for developing a drug of neurodegenerative disease.METHODS Rat cortex neurons were isolated from one day old Sprague Dawley rats and treated with estrogen,quercetin and estrogen receptor antagonists(ICI182,780).Cell viability was determined by MTT assay,neurite outgrowth was measured by fluorescent microsope and estrogen receptors were determine by Western blot.RESULTS Quercetin functions like estrogen to increase cortex neuronal cell viability,the Que(50,100μmol·L^(-1))group compared with the control group could significantly improve the activity of the cortical neurons(P<0.05).It can also increase neurite out growth,the Que(50,100μmol·L^(-1))group significantly promoted the formation of synapse,most of the neurons were full,and the synapses of neurons became thick,growth,and connect to a dense neural network.And in the Western blot experiments,Que(50,100μmol·L^(-1))group could obviously increase the expression of estrogen receptor alpha protein,in addition,the neural protective effect of quercetin can be inhibited by ICI182,780.CONCLUSION Quercetin like estrogen can protected cortex neuronal and the effect of quercetin on cortex neuronal cells was mediated by estrogen receptor alpha.

Histological Patterns of Neurodegeneration of Frontal Cortex Neurons in Datura stramonium Treated Wistar Rats

Aim: Datura stramonium (DS) is a known hallucinogen and depressant of the central nervous system, but it is commonly used in alcoholic beverages to increase intoxication. Pharmacological, physiological and ultra-structural studies have demonstrated the neurotoxicity of this drug inanimals and humans at high doses. The present study investigated the histological patterns of neurodegeneration of frontal cortex (FC) neurons in Wistar rats treated with high doses of DS seed extract. Materials and methods: Ethanolic extract of DS dried seeds was diluted in normal saline and administered to male and female Wistar rats weighing 200 g - 250 g. The animals were first placed in three groups which were further sub-divided into four sub-groups. The treated sub-groups received intraperitoneal administration (i.p.) of 750 mg/kg of diluted DS seed extract once daily in group 1, twice daily (1500 mg/kg/day) in group 2 and thrice daily (2250 mg/kg/day) in group 3. The treatment was carried out for 4 weeks while the control groups received normal saline during the same period. The rats were euthanized and sections of the frontal cortices of the brain were histologically processed from all groups. Silver impregnation stain for degenerating axons and neurons was used to elucidate the pattern of degeneration induced by DS seed extract on the neurons of the FC. Results: The results of intraperitoneal administration of DS extract showed no changes in groups 1 & 2 treated rats while group 3 showed a significant pattern of histological changes like axonal atrophy, vacuolization and neuronal deaths in the frontal cortices neurons compared to the controls. Conclusion: DS may have a specific pattern of neurodegeneration at higher doses of administration. This could provide a useful model in understanding how DS intoxication can affect frontal cortex neurons with an implication of neurological disorders, mental diseases and behavioural deficits.

Lesions of mediodorsal thalamic nucleus reverse abnormal firing of the medial prefrontal cortex neurons in parkinsonian rats

The dysfunction of the medial prefrontal cortex is associated with affective disorders and non-motor features in Parkinson’s disease.However,the exact role of the mediodorsal thalamic nucleus in the function of the prefrontal cortex remains unclear.To study the possible effects of the mediodorsal thalamic nucleus on the neurological function of the medial prefrontal cortex,a model of Parkinson’s disease was established by injecting 8μg 6-hydroxydopamine into the substantia nigra compacta of rats.After 1 or 3 weeks,0.3μg ibotenic acid was injected into the mediodorsal thalamic nucleus of the midbrain.At 3 or 5 weeks after the initial injury,neuronal discharge in medial prefrontal cortex of rat brain was determined electrophysiologically.The numbers of dopamine-positive neurons and tyrosine hydroxylase immunoreactivity in substantia nigra compacta and ventral tegmental area were detected by immunohistochemical staining.Results demonstrated that after injury,the immunoreactivity of dopamine neurons and tyrosine hydroxylase decreased in the substantia nigra compacta and ventral tegmental areas of rats.Compared with normal medial prefrontal cortical neurons,at 3 and 5 weeks after substantia nigra compacta injury,the discharge frequency of pyramidal neurons increased and the discharge pattern of these neurons tended to be a burst-discharge,with an increased discharge interval.The discharge frequency of interneurons decreased and the discharge pattern also tended to be a burst-discharge,but the discharge interval was only higher at 3 weeks.At 3 weeks after the combined lesions,the discharge frequency,discharge pattern and discharge interval were restored to a normal level in pyramidal neurons and interneurons in medial prefrontal cortex.These findings have confirmed that mediodorsal thalamic nucleus is involved in regulating neuronal activities of the medial prefrontal cortex.The changes in the function of the mediodorsal thalamic nucleus may be associated with the abnormal discharge activity of the medial prefrontal cortex neurons after substantia nigra compacta injury.All experimental procedures were approved by the Institutional Animal Care and Use Committee of Xi’an Jiaotong University,China(approval No.XJTULAC2017-067)on August 26,2017.

Activation of Parvalbumin-Positive Neurons in Both Retina and Primary Visual Cortex Improves the Feature-Selectivity of Primary Visual Cortex Neurons

Several recent studies using either viral or transgenic mouse models have shown different results on whether the activation of parvalbumin-positive（PV~＋）neurons expressing channelrhodopsin-2（ChR2） in the primary visual cortex（V1） improves the orientation-and direction-selectivity of V1 neurons. Although this discrepancy was thoroughly discussed in a follow-up communication, the issue of using different models to express ChR2 in V1 was not mentioned. We found that ChR2 was expressed in retinal ganglion cells（RGCs） and V1 neurons in ChR2fl/~＋; PV-Cre mice. Our results showed that the activation of PV~＋RGCs using white drifting gratings alone significantly decreased the firing rates of V1 neurons and improved their direction-and orientation-selectivity. Longduration activation of PV~＋interneurons in V1 further enhanced the feature-selectivity of V1 neurons in anesthetized mice, confirming the conclusions from previous findings. These results suggest that the activation of both PV~＋RGCs and V1 neurons improves feature-selectivity in mice.

A Disintegrin and Metalloprotease 10 in neuronal maturation and gliogenesis during cortex development

The multiple-layer structure of the cerebral cortex is important for its functions. Such a structure is generated based on the proliferation and differentiation of neural stem/progenitor cells. Notch functions as a molecular switch for neural stem/progenitor cell fate during cortex development but the mechanism remains unclear. Biochemical and cellular studies showed that Notch receptor activation induces several proteases to release the Notch intracellular domain （NICD）. A Disintegrin and Metalloprotease 10 （ADAM10） might be a physiological rate-limiting $2 enzyme for Notch activation. Nestin-driven conditional ADAM10 knockout in mouse cortex showed that ADAM10 is cdtical for maintenance of the neural stem cell population during early embryonic cortex development. However, the expression pattern and function of ADAM10 during later cerebral cortex development remains poorly understood. We performed in situ hybridization for ADAMIO mRNA and immunofluorescent analysis to determine the expression of ADAM10 and NICD in mouse cortex from embryonic day 9 （E14.5） to postnatal day 1 （P1）. ADAM10 and NICD were highly co-localized in the cortex of E16.5 to P1 mice. Comparisons of expression patterns of ADAM10 with Nestin （neural stem cell marker）, Tujl （mature neuron marker）, and S100β （gila marker） showed that ADAM10 expression highly matched that of S10013 and partially matched that of Tujl at later embryonic to early postnatal cortex developmental stages. Such expression patterns indicated that ADAM10-Notch signaling might have a critical function in neuronal maturation and gliogenesis during cortex development.

Expression of c-Fos protein and nitricoxide synthase in neurons of cerebral cortex from fetal rats in hypoxia and protective role of Angelica sinensis

BACKGROUND： Both c-Fos protein and nitricoxide synthase （NOS） have been used as general indexes in relative research about neurons, but it is lack of reports that c-Fos protein and NOS are applied synchronously to study the neurons of hypoxic fetal rats in uterus. OBJECTIVE： To study the effect of hypoxia in uterus on the expression of c-Fos protein and NOS in neurons of cerebral cortex from fetal rats and whether Angelica sinensis has the protective effect on these neurons in hypoxia. DESIGN： Randomized control experiment.SETTING ： Department of Histology and Embryology, Luzhou Medical College.MATERIALS ： Twelve adult female Wistar rats in oestrum and 1 male Wistar rat with bodymass from 220 to 250 g were chosen. Parenteral solution of Angelica sinensis mainly contained angelica sinensis, 10 mL/ampoule, was provided by Department of Agent of the Second Hospital Affiliated to Hubei Medical University （batch number： 01062310）. METHODS ： This experiment was completed in the Department of Histology and Embryology of Luzhou Medical College from September 2003 to June 2004. ①Twelve adult female Wistar rats in oestrum and 1 male Wistar rat were housed in one rearing cage. Vaginal embolus was performed on conceive female rat at 8： 00 am next day. On the 15^th conceiving day, all conceiving rats were divided randomly into three groups： control group, hypoxia group and Angelica group with 4 in each group. Rats in hypoxia group and Angelica group were modeled with hypotonic hypoxia in uterus. Angelica group： Rats were injected with 8 mL/kg Angelica sinensis injection through caudal veins before hypoxia. Hypoxia group： Rats were injected with the same volume of saline. Control group： Rats were not modeled and fed with normal way. ② Twenty embryos of rats were chosen randomly from each group and then routinely embedded in paraffin. Paraffin sections were cut from the brain of embryos to anterior fontanelle. Double-label staining was used to detect the expression of nNOS and c-Fos in neurons of cerebral cortex from embryos of rats. OLYMPUS Bx-50 microscope was used to observe sections and DP12 digit camera was also used under 400 times to detect types of cells. Under microscope, the number of c-Fos, NOS, c-Fos/NOS positive neurons in cerebral cortex from embryos of rats were counted in 2 fields with magnification of 400 in one section per animal. ③ The data in experiments were analyzed by one-way analysis of variance （ANOVA） followed by q test. MAIN OUTCOME MEASURES： ① Results of immunohistochemical double-label staining of c-Fos/NOS from cerebral cortex; ② Comparison of amount immunohistochemical double-label staining of c-Fos/NOS positive cells from cerebral cortex. RESULTS：① The positive NOS cells and c-Fos/NOS cells in the three groups were mainly distributed in cerebral cortex, but positive c-Fos neurons were not observed. ② Positive NOS cells and c-Fos/NOS cells in hypoxia group were more than those in control group （76.55±12.02, 50.45±10.39; 33.35±7.42, 26.35±6.67, P 〈 0.05）, but those in Angelica group were less than those in hypoxia group （51.70±9.82, 35.65±8.37, P 〈 0.05）. CONCLUSION： Hypoxia can stimulate the increase of expression of c-Fos protein and NOS in neurons of cerebral cortex. However, Angelica sinensis can decrease this expression so as to play a protective role in cerebral neurons of hypoxic fetal rats.

The Distribution and Morphological Diversity of GABA-containing Neurons in The Prefrontal Cortex of Human Newborn Baby Infant

The prefrontal cortex of a human full termnewborn infant just after accidental death was studies by mcans of immunocytochemical technique with antibody directedagainst GABA(Immunonuclear Corp.)and ABC kit(Vector)。GABA-containing neurons were found over all layers and all were nonpyramidal cells.The laminar distribution of GABA-containing ne-urons was not even between different layers,density in laye Ⅱ was prominently higher than any other layers,density in layer Ⅲ and layer Ⅳ was higher than that in layer V and Ⅵ.

基于胶质细胞GR/CX3CR1双信号探讨柴金解郁安神片含药血清减轻体外抑郁模型大鼠ACC神经元突触损伤的机制

目的:基于胶质细胞糖皮质激素受体(glucocorticoid receptor,GR)/CX3C趋化因子受体1(CX3C chemokine receptor 1,CX3CR1)双信号探讨柴金解郁安神片(CJJY)含药血清对体外抑郁模型中大鼠前扣带皮层(anterior cingulate cortex,ACC)神经元突触损伤的保护机制。方法:原代培养SD大鼠ACC脑区星形胶质细胞、小胶质细胞和神经元,并分别进行鉴定;采用200μmol/L皮质酮(corticosterone,CORT)联合1 mg/L脂多糖(lipopolysaccharide,LPS)建立模拟抑郁环境的体外细胞模型,实验设正常组、模型组(CORT+LPS)、GR阻断剂(GR-)组(CORT+LPS+RU486)、GR激动剂(GR+)组(CORT+LPS+dexamethasone)、CX3CR1阻断剂(CX3-)组(CORT+LPS+AZD8797)、CX3CR1激动剂(CX3+)组(CORT+LPS+fractalkine)、CJJY组(CORT+LPS+CJJY含药血清)、CJJY联合GR激动剂(CJJY/GR+)组(CORT+LPS+CJJY含药血清+dexamethasone)组和CJJY联合CX3CR1激动剂(CJJY/CX3+)组(CORT+LPS+CJJY含药血清+fractalkine);高内涵细胞成像分析技术观察星形胶质细胞、小胶质细胞和ACC神经元形态学变化;ELISA法检测细胞上清液中促肾上腺皮质激素(adrenocorticotropic hormone,ACTH)、促肾上腺皮质激素释放激素(corticotropin-releasing hormone,CRH)、CORT、肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)、白细胞介素1β(interleukin-1β,IL-1β)、IL-6和谷氨酸(glutamate,Glu)水平;免疫荧光染色检测星形胶质细胞中GR和囊泡谷氨酸转运体1(vesicular glutamate transporter 1,VGluT1)表达水平,以及小胶质细胞中CX3CR1和腺苷A2A受体(adenosine A2A receptor,A2AR)表达水平;Nissl染色和β-tubulin染色观察神经元突触损伤情况。结果:CJJY含药血清能减轻体外抑郁模型中大鼠星形胶质细胞损伤,抑制小胶质细胞激活,同时抑制细胞上清液中ACTH、CRH、CORT、TNF-α、IL-1β、IL-6和Glu水平异常增高(P<0.05或P<0.01),有效调控GR、VGluT1、CX3CR1和A2AR表达异常(P<0.05或P<0.01),并减轻大鼠ACC神经元树突和树突棘损伤。结论:CJJY含药血清通过调控胶质细胞GR/CX3CR1双信号而减轻体外抑郁模型中大鼠ACC神经元突触损伤。

C57BL/6小鼠大脑皮层区与基底神经节隆起区神经元突触发育过程比较

目的:观察小鼠皮层区和基底神经节隆起(GE)区神经元突触发育过程,阐明兴奋性突触和抑制性突触在不同脑区的体内外发育差异。方法:C57BL/6雌鼠于妊娠第13.5~15.5天断颈处死后,经无菌操作取胚胎小鼠,显微镜下逐步分离获取胚胎小鼠脑组织皮层区和GE区。体外原代培养胚胎小鼠神经元,于培养3、7、14和21 d分别收集细胞样品,并将其作为培养3、7、14和21 d组。采用实时荧光定量PCR(RT-qPCR)法检测各组小鼠皮层区和GE区原代培养神经元中突触后表达蛋白突触后密度蛋白95(PSD95)及桥尾蛋白(Gephyrin) mRNA表达水平。免疫荧光法检测各组小鼠皮层区和GE区原代培养神经元中囊泡谷氨酸转运蛋白1(vGLUT1)、 PSD95、囊泡γ-氨基丁酸(GABA)转运蛋白(vGAT)及Gephyrin蛋白表达水平。免疫荧光法检测胚胎小鼠脑组织皮层区和GE区神经元中vGLUT1及vGAT蛋白表达水平。结果:与培养3 d组比较,培养14和21 d组小鼠皮层区和GE区原代培养神经元中PSD95及Gephyrin mRNA表达水平明显升高(P<0.01);与皮层区比较,培养14 d组小鼠GE区原代培养神经元中Gephyrin mRNA表达水平明显降低(P<0.01)。显微镜下观察,培养14 d组小鼠皮层区和GE区原代培养神经元中兴奋性突触及抑制性突触均初步发育,相关蛋白呈阳性表达;其中兴奋性突触相关蛋白阳性表达在皮层区神经元中更为明显,且突触前分子vGLUT1和突触后分子PSD95在皮层区神经元的胞体及突起部位均呈现共定位的特征;抑制性突触前分子vGAT蛋白和突触后分子Gephyrin蛋白在GE区神经元胞体及突起中也呈现共定位的特征,且突触前分子较相应的突触后分子蛋白阳性表达更明显。与皮层区比较,培养14 d组小鼠GE区原代培养神经元中vGLUT1和PSD95蛋白表达水平明显降低(P<0.01),vGAT和Gephyrin蛋白表达水平明显升高(P<0.01)。培养21 d组小鼠皮层区和GE区原代培养神经元突触相关蛋白阳性表达增加,兴奋性突触和抑制性突触进一步成熟并完善。皮层区和GE区原代培养神经元的胞体及突起部位均形成了丰富的突触前后对应的表达模式,突触结构逐步发育良好,且突触前分子较相应的突触后分子蛋白阳性表达更明显。与皮层区比较,培养21 d组小鼠GE区原代培养神经元中vGLUT1和PSD95蛋白表达水平均明显降低(P<0.01),vGAT和Gephyrin蛋白表达水平均明显升高(P<0.01)。与皮层区比较,胚胎小鼠脑组织GE区神经元中vGLUT1蛋白表达水平明显降低(P<0.01),vGAT蛋白表达水平明显升高(P<0.05)。结论:皮层区和GE区神经元的突触发育具有明显的差异性,皮层区兴奋性突触发育较早,GE区抑制性突触发育较早。突触的脑区特异性发育提示不同细胞类型的神经疾病可能具有不同的发育来源。

内侧前额叶皮质谷氨酸能神经元参与CD1小鼠攻击行为的机制研究

目的研究CD1小鼠发动攻击行为的内在神经机制。方法通过驻地入侵实验筛选出具有攻击行为的CD1小鼠,攻击配对偏好进一步验证后使用c-Fos标记全脑激活的脑区,通过免疫荧光双标实验分析攻击行为激活了哪种类型的神经元,最后使用光遗传学调控该类神经元的活性,观察其对攻击行为的影响。结果通过c-Fos筛选,约82%的CD1小鼠表现出攻击行为;攻击行为发生后主要激活内侧前额叶皮质(medial prefrontal cortex,mPFC),免疫荧光双标结果显示mPFC脑区c-Fos阳性神经元主要是谷氨酸能神经元;最后,我们通过光遗传激活mPFC脑区谷氨酸能神经元,发现其能够抑制CD1小鼠的攻击行为;相反,光遗传抑制mPFC脑区谷氨酸能神经元,能够促进CD1小鼠的攻击行为。结论mPFC脑区谷氨酸能神经元是调控CD1小鼠发动攻击行为的重要组成部分。

无镁诱导仓鼠原代皮质神经元电生理学特性

目的无镁细胞外液建立癫痫放电模型,利用全细胞膜片钳技术,检测仓鼠原代皮质神经元的电生理学特性。方法采用生后1~2 d新生叙利亚仓鼠,分离大脑皮质培养原代神经元培养至第12天,分别予有镁细胞外液(有镁组)和无镁细胞外液(无镁组)孵育3 h,3 h后均更换为正常孵育液继续培养24 h。利用全细胞膜片钳技术,电压钳模式下记录神经元兴奋性突触后电流(excitatory postsynaptic currents,EPSC),电流钳模式下记录神经元兴奋性突触后电位(excitatory postsynaptic potentials,EPSP)。结果与有镁组相比,无镁组仓鼠原代皮质神经元EPSC[(124.38±75.15)Hz vs.(33.93±22.32)Hz,P<0.001]及EPSP[(37.05±38.37)Hz vs.(5.63±9.52)Hz,P<0.01]的频率升高,且差异有统计学意义;而两组之间EPSC及EPSP的振幅、曲线下面积和半宽度的差异无统计学意义(P>0.05)。结论无镁处理后仓鼠原代皮质神经元兴奋性升高,仓鼠原代皮质神经元可用于构建癫痫细胞模型。

前额叶皮层在社交行为中的作用

社交行为对于个体身心健康和社会发展都极其重要。社交行为障碍已成为多种精神类疾病的典型临床表征,对个体的发展有严重不良影响。前额叶皮层作为调节社交行为的关键脑区之一,参与了社交、情绪、决策等高级功能,其内部神经元、神经胶质细胞的活动变化及相互作用对调节社交行为有着重要影响,而且前额叶皮层与其他脑区之间的协作也会影响不同的社会行为。本文回顾了前额叶皮层中神经元、神经胶质细胞以及脑区投射与社交行为关系的最新研究,系统综述了前额叶皮层在社交行为调节中的作用,以期为社交障碍的神经机制和有效诊疗提供参考。

虎杖苷对β淀粉样蛋白诱导体外皮质神经元线粒体氧化应激和功能障碍的保护作用

目的探讨虎杖苷对β淀粉样蛋白25~35(Aβ_(25~35))诱导的原代培养大鼠皮质神经元损伤的保护作用及可能的作用机制。方法原代培养SD大鼠皮质神经元,分为对照组、虎杖苷组、Aβ_(25~35)组和联合组(Aβ_(25~35)+虎杖苷)。采用四甲基偶氮唑盐检测皮质神经元活力,2,7-二氯荧光素二乙酸酯探针或红色线粒体超氧化物荧光探针染色检测细胞内和线粒体活性氧水平,线粒体膜通透性转换孔(MPTP)试剂盒检测MPTP开放程度,蛋白免疫印记法检测细胞色素C及线粒体转录因子A(TFAM)表达。另外,测定细胞内电子传递链复合物(包括复合物Ⅰ、Ⅱ、Ⅲ、Ⅳ)活性和三磷酸腺苷(ATP)水平。采用高效液相色谱法测定线粒体中8-羟基脱氧鸟苷(8-OHdG)。结果与对照组比较,Aβ_(25~35)组皮质神经元细胞活力、线粒体荧光强度、线粒体呼吸链酶活性(复合物Ⅰ、Ⅱ、Ⅲ、Ⅳ)、细胞内ATP、线粒体内TFAM表达明显降低,差异有统计学意义(P<0.05,P<0.01);与Aβ_(25~35)组比较,虎杖苷组线粒体荧光强度、线粒体呼吸链酶活性(复合物Ⅰ、Ⅱ、Ⅲ、Ⅳ)、细胞内ATP、线粒体内TFAM表达明显增高,皮质神经元暴露3、6、12、24h细胞内和线粒体内活性氧明显降低(P<0.05,P<0.01),联合组细胞色素C细胞质/线粒体比值、线粒体内8-OHdG水平明显低于Aβ_(25~35)组[3.02±0.28 vs 5.73±0.45,P<0.05;(8.07±1.45)×10^(6)dG vs(16.07±2.29)×10^(6)dG,P<0.05]。结论虎杖苷可有效地保护皮质神经元免受Aβ_(25~35)诱导的损伤,至少部分作用是通过抑制线粒体氧化应激和改善线粒体功能实现。

前扣带回皮层中CaMKⅡα^(+)GAD67^(+)神经元在大鼠神经病理性疼痛和焦虑抑郁共病中的作用

目的探讨前扣带回皮层(ACC)中表达钙/钙调素依赖性蛋白激酶Ⅱ(CaMKⅡ)的兴奋性神经元和表达谷氨酸脱羧酶67(GAD67)的抑制性神经元在神经病理性疼痛以及焦虑、抑郁共病中的作用。方法雄性SD大鼠72只,随机分为假手术组(Sham)、神经病理性疼痛组(CCI)、神经病理性疼痛+CaMKⅡα非激活组(CCI+hM4Di^(-))、神经病理性疼痛+CaMKⅡα激活组(CCI+hM4Di^(+))、神经病理性疼痛+GAD67非激活组(CCI+hM3Dq^(-))、神经病理性疼痛+GAD67激活组(CCI+hM3Dq^(+))。通过由专门设计药物技术激活的设计受体(DREADDs)偶联hM3Dq或hM4Di,以细胞类型和时间依赖性的方式调控神经元活性。以机械缩足阈值(PWT)、热缩足潜伏期(PWL)评估疼痛行为,旷场试验、新环境进食抑制试验、强迫游泳试验评估焦虑、抑郁样行为,WesternBlot检测CaMKⅡα和GAD67表达,c-Fos免疫荧光染色检测神经元激活情况。结果与Sham组相比,CCI组大鼠术后表现出机械痛觉过敏和热痛觉超敏反应以及焦虑、抑郁样行为;对侧ACC中CaMKⅡα蛋白表达水平升高,GAD67蛋白表达水平降低;免疫荧光染色显示CaMKⅡα+神经元激活增多,GAD67^(+)神经元激活减少。与CCI+hM4Di^(-)组大鼠相比,CCI+hM4Di^(+)组在术后28 dPWL、PWT升高,焦虑和抑郁样行为改善。与CCI+hM3Dq^(-)组相比,CCI+hM3Dq^(+)组在术后28dPWL、PWT升高,焦虑、抑郁样行为减少。结论抑制ACC中CaMKⅡα+兴奋性神经元或激活GAD67^(+)抑制性神经元能起到减轻NP大鼠疼痛,改善焦虑、抑郁样行为的作用。

Dual face of axonal inhibitory inputs in the modulation of neuronal excitability in cortical pyramidal neurons

Limited by the tiny structure of axons,the effects of these axonal hyperpolarizing inputs on neuronal activity have not been directly elucidated.Here,we imitated these processes by simultaneously recording the activities of the somas and proximal axons of cortical pyramidal neurons.We found that spikes and subthreshold potentials propagate between somas and axons with high fidelity.Furthermore,inhibitory inputs on axons have opposite effects on neuronal activity according to their temporal integration with upstream signals.Concurrent with somatic depolarization,inhibitory inputs on axons decrease neuronal excitability and impede spike generation.In addition,following action potentials,inhibitory inputs on an axon increase neuronal spike capacity and improve spike precision.These results indicate that inhibitory inputs on proximal axons have dual regulatory functions in neuronal activity（suppression or facilitation）according to neuronal network patterns.

Cortical regulation of striatal projection neurons and interneurons in a Parkinson's disease rat model

Striatal neurons can be either projection neurons or interneurons, with each type exhibiting distinct susceptibility to various types of brain damage. In this study, 6-hydroxydopamine was injected into the right medial forebrain bundle to induce dopamine depletion, and/or ibotenic acid was injected into the M1 cortex to induce motor cortex lesions. Immunohistochemistry and western blot assay showed that dopaminergic depletion results in significant loss of striatal projection neurons marked by dopamine- and cyclic adenosine monophosphate-regulated phosphoprotein, molecular weight 32 k Da, calbindin, and μ-opioid receptor, while cortical lesions reversed these pathological changes. After dopaminergic deletion, the number of neuropeptide Y-positive striatal interneurons markedly increased, which was also inhibited by cortical lesioning. No noticeable change in the number of parvalbumin-positive interneurons was found in 6-hydroxydopamine-treated rats. Striatal projection neurons and interneurons show different susceptibility to dopaminergic depletion. Further, cortical lesions inhibit striatal dysfunction and damage induced by 6-hydroxydopamine, which provides a new possibility for clinical treatment of Parkinson＇s disease.

Adaptation to visual stimulation modifies the burst firing property of V1 neurons

The mean firing rate of visual cortical neurons is reduced after prolonged visual stimulation, but the underlying process by which this occurs as well as the biological significance of this phenomenon remains unknown. Computational neuroscience studies indicate that high-frequency bursts in stimulus-driven responses can be transmitted across synapses more reliably than isolated spikes, and thus may carry accurate stimulus-related information. Our research examined whether or not adaptation affects the burst firing property of visual cortical neurons by examining changes in the burst firing changes of V1 neurons during adaptation to the preferred visual stimulus. The results show that adaptation to prolonged visual stimulation significantly decreased burst frequency （bursts/s） and burst length （spikes/burst）, but increased burst duration and the interspike interval within bursts. These results suggest that the adaptation of V1 neurons to visual stimulation may result in a decrease of feedforward response gain but an increase of functional activities from lateral and/or feedback connections, which could lead to a reduction in the effectiveness of adapted neurons in transmitting information to its driven neurons.