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目的:探讨朱砂安神丸对条件性恐惧大鼠恐惧记忆的影响及作用机制。 方法:将90只雄性SD大鼠随机分为空白组、模型组、给药组,每组30只;给药组大鼠灌胃给予朱砂安神丸混悬液(给药体积为每100 g大鼠体质量0.9 mL),空白组、模型组大鼠给予等量的双蒸水,各组大鼠均连续干预7 d。末次给药后复制条件性恐惧模型。通过条件性恐惧实验监测系统观察各组大鼠的僵直反应时间,考察朱砂安神丸对恐惧记忆的影响;通过电生理实验和透射电镜技术,考察朱砂安神丸对海马功能结构可塑性的影响。 结果:与模型组比较,给药组(朱砂安神丸)能有效促进条件性恐惧大鼠恐惧记忆消退,恐惧记忆习得阶段及消退阶段僵直反应时间明显减少,运动时间、运动距离明显增加,诱发海马部位LTP其PS幅值明显减少(P<0.05,P<0.01);海马神经元突触数目较多,突触各部分结构完好、界限清晰,海马突触活性区长度及PSD厚度明显增大,突触间隙宽度明显减小(P<0.05,P<0.01);海马神经元细胞各结构完整清晰,细胞核大,细胞浆内细胞器较多、形态较好。 结论:朱砂安神丸具有促进恐惧记忆消退的作用,其作用机制与保护海马神经元、调节海马突触结构和功能可塑性有关。 相似文献
2.
The specific role of postsynaptic activity for the generation of a functional magnetic resonance imaging (fMRI) response was determined by a simultaneous measurement of generated field excitatory postsynaptic potentials (fEPSPs) and blood oxygen level-dependent (BOLD) response in the rat hippocampal CA1 region during electrical stimulation of the contralateral CA3 region. The stimulation electrode was placed either in the left CA3a/b or CA3c, causing the preferentially basal or apical dendrites of the pyramidal cells in the right CA1 to be activated. Consecutive stimulations with low-intensity stimulation trains (i.e., 16 pulses for 8 seconds) resulted in clear postsynaptic responses of CA1 pyramidal cells, but in no significant BOLD responses. In contrast, consecutive high-intensity stimulation trains resulted in stronger postsynaptic responses that came along with minor (during stimulation of the left CA3a/b) or substantial (during stimulation of the left CA3c) spiking activity of the CA1 pyramidal cells, and resulted in the generation of significant BOLD responses in the left and right hippocampus. Correlating the electrophysiologic parameters of CA1 pyramidal cell activity (fEPSP and spiking activity) with the resultant BOLD response revealed no positive correlation. Consequently, postsynaptic activity of pyramidal cells, the most abundant neurons in the CA1, is not directly linked to the measured BOLD response. 相似文献
3.
Sanne J. H. van Rooij Ryan D. Smith Anaïs F. Stenson Timothy D. Ely Xinyi Yang Nim Tottenham Jennifer S. Stevens Tanja Jovanovic 《Depression and anxiety》2020,37(4):303-312
Most studies investigating the effect of childhood trauma on the brain are retrospective and mainly focus on maltreatment, whereas different types of trauma exposure such as growing up in a violent neighborhood, as well as developmental stage, could have differential effects on brain structure and function. The current magnetic resonance imaging study assessed the effect of trauma exposure broadly and violence exposure more specifically, as well as developmental stage on the fear neurocircuitry in 8‐ to 14‐year‐old children and adolescents (N = 69). We observed reduced hippocampal and increased amygdala volume with increasing levels of trauma exposure. Second, higher levels of violence exposure were associated with increased activation in the amygdala, hippocampus, and ventromedial prefrontal cortex during emotional response inhibition. This association was specifically observed in children younger than 10 years. Finally, increased functional connectivity between the amygdala and brainstem was associated with higher levels of violence exposure. Based on the current findings, it could be hypothesized that trauma exposure during childhood results in structural changes that are associated with later risk for psychiatric disorders. At the same time, it could be postulated that growing up in an unsafe environment leads the brain to functionally adapt to this situation in a way that promotes survival, where the long‐term costs or consequences of these adaptations are largely unknown and an area for future investigations. 相似文献
4.
目的研究离体培养的海马神经元LKB1表达下调对于神经元微小兴奋性突触后电流(mEP-SC)的影响。方法选用17d的胚胎大鼠培养海马神经元,分别用电穿孔的方法转染CAG-RE质粒和LKB1RNAi质粒,培养10~12d后进行电生理记录,选用全细胞膜片钳方式及自由记录模式,细胞外液加TTX阻断动作电位,加Bicucullin抑制GABA电流,记录神经元的mEPSC,比较2组神经元的mEPSC频率和幅度的差别。结果转染CAG-RE的神经元mEPSC幅度平均为25.6pA,频率平均为(5.21±0.25)Hz,是基线的99.8%;转染LKB1RNAi的神经元mEPSC幅度平均为35.1pA,频率平均为(5.79±0.27)Hz,是基线的127.1%;比较2组间频率、幅度变化,差别有显著性意义(P<0.05)。结论LKB1基因表达下调增强了培养海马神经元突触传递的效率。 相似文献
5.
加锌对大鼠脑内微量元素的影响 总被引:1,自引:0,他引:1
龚云 《微量元素与健康研究》2005,22(4):7-8
用SD雌性成年大鼠20只,随机分为实验组和对照组各10只。加锌40d后,用原子吸收分光光度计(日本津岛)分别测定了两组大鼠大脑皮质感觉运动区和海马CA3区的微量元素Zn、Cu、Fe和轻金属Mg的含量。结果表明:在大脑皮质感觉运动区,两组大鼠的诸元素含量无显著变化;在海马CA3区,两组大鼠的微量元素Zn、Cu、Fe的含量也无显著变化(P>0.05),但轻金属Mg的含量却发生了显著的变化,表现为对照组明显高于实验组(P<0.05)。 相似文献
6.
钾通道阻断剂对低氧/复氧诱导的培养海马神经元死亡的防护作用 总被引:3,自引:0,他引:3
目的研究钾通道阻断剂对单纯低氧/复氧诱导的培养海马神经元死亡的防护作用。方法培养8 d的海马神经元置于低氧环境(95% N2/5% CO2)6 h,复氧再培养直至72 h,复氧后0.5 h培养液内分别给予不同钾通道阻断剂,用细胞计数及MTT比色法检测神经元死亡情况。结果低氧/复氧诱导培养海马神经元出现迟发性死亡;四乙铵以剂量依赖性的方式防护低氧/复氧诱导的培养海马神经元免于死亡;大电导钙激活钾通道(BK通道)阻断剂iberiotoxin(IbTX)可完全消除低氧/复氧诱导的神经元死亡(P<0.001);A型钾通道阻断剂4-氨基吡啶不能防护低氧/复氧诱导的神经元免于死亡(P>0.05)。结论钾通道阻断剂四乙铵和IbTX能防护低氧/复氧诱导的培养海马神经元免于死亡,提示某些类型的钾通道尤其是BK通道活动增强可能参与了低氧/复氧诱导的培养海马神经元死亡。 相似文献
7.
R. N. KALARIA ‡‡ P. G. GALLOWAY† G. PERRY‡ ‡‡ 《Neuropathology and applied neurobiology》1991,17(3):189-201
Amyloid P (AP) component is present in all types of systemic amyloid deposits. Recently, it has been shown to be also present in cerebral amyloid lesions of Alzheimer's disease (AD). In this study, we used immunocytochemical methods to extend these findings at the electron microscope level and characterize the spectrum of AP immunoreactivity in neurofibrillary pathology (NFP) of AD and other neurodegenerative disorders including Down's syndrome (DS), Creutzfeldt-Jakob, Parkinson's, Pick's and diffuse Lewy body diseases and progressive supranuclear palsy. In AD and DS, AP immunoreaction product was evident in all the classical amyloid lesions and NFP in a large sample of all cortical areas examined. The distribution and relative intensity of immunostaining was similar to that of thioflavin S staining in serial sections. In many cases, however, plaques and vessels stained by anti-AP serum were not apparent with thioflavin S. Serial sections immunostained with antiserum to amyloid A, C-reactive protein or to other proteins involved in systemic amyloidoses and the acute phase response showed no evidence of staining in any of the cerebral lesions. Electron microscopy confirmed that AP immunoreactivity was associated with the abnormal filaments characteristic of NFP as well as amyloid fibrils found in plaques and vessels showing congophilic amyloid angiopathy. Plaques of Creutzfeldt-Jakob disease, Pick bodies of Pick's disease, tangles and Lewy bodies in Parkinson's disease and a subpopulation of Lewy bodies in the diffuse Lewy body disease coexistent with AD were also stained. With the exception of vessels in two of the five cases, AP was not detected in age-matched controls. Our observations indicate AP to be a consistent feature of cerebral NFP and amyloid deposits. 相似文献
8.
普洛托品对正常大鼠学习能力及海马、大脑皮层乙酰胆碱酯酶活性的影响 总被引:2,自引:0,他引:2
目的:观察普洛托品(protopine,Pro)对正常大鼠学习能力及海马、大脑皮层乙酰胆碱酯酶活性的影响。方法:大鼠每天Pro 0.5mg/kg灌胃,28d后三等分Y迷宫测定大鼠学习成绩,并测定海马及大脑皮层乙酰胆碱酯酶活性。结果:Pro组大鼠达到学会标准所需的训练次数明显减少,与对照组比较差异有极显著性(P<0.01),Pro组大鼠海马及大脑皮层乙酰胆碱酯酶活性亦明显降低,与对照组比较差异有显著性(P<0.01,P<0.05),结论:Pro可提高正常大鼠学习能力,并降低海马及大脑皮层乙酰胆碱酯酶活性。 相似文献
9.
10.
Long Fibre Growth by Axons of Embryonic Mouse Hippocampal Neurons Microtransplanted into the Adult Rat Fimbria 总被引:1,自引:0,他引:1
We have described a method for the microtransplantation of a suspension of a few thousand cells from mid to late embryonic mouse hippocampi into the fimbria of immunosuppressed adult rat hosts. There was close graft-to-host contact, across a non-scarred interface. The transplanted cells included CA3 type pyramids, and were enclosed within the host myelinated fibre tract, whose glial framework was largely undisturbed. Immunohistochemistry of two species-specific markers (M6 and Thy-1.2) showed that the donor mouse neurons grew fine (<0.5 μm diameter) axons which extended singly or in fascicles through the rat host fimbria for a maximum distance of at least 10 mm. The donor axons were intimately integrated among and closely aligned to the host tract axons and to the interfascicular glial rows of the host tract. The axons travelled (i) laterally through the ipsilateral fimbria, (ii) medially across the midline in the ventral hippocampal commissure to reach the contralateral fimbria and alveus, and (iii) rostro-medially to the septum. On approaching the terminal fields appropriate to hippocampal CA3 pyramidal cell axons, the transplant axons gave rise to fine preterminal branches which were continuous with a reticular or amorphous immunoreactivity in the stratum oriens and stratum pyramidale of the ipsilateral hippocampus, and in the lateral and triangular septal nuclei. The donor axons extended along the host fimbria at a rate of ∼ 1 mm per day, reaching their terminal field destinations by ∼1–2 weeks. At 7 weeks the projections were maintained, but with little further extension. These observations indicate that the microenvironment of myelinated adult fibre tracts is permissive for an abundant and rapid growth of axons from transplanted embryonic cell suspensions. These axons can leave host tracts to invade appropriate terminal fields. 相似文献