Electroacupuncture Alleviates Memory Deficits in APP/PS1 Mice by Targeting Serotonergic Neurons in Dorsal Raphe Nucleus

Objective Alzheimer’s disease(AD)has become a significant global concern,but effective drugs able to slow down AD progression is still lacked.Electroacupuncture(EA)has been demonstrated to ameliorate cognitive impairment in individuals with AD.However,the underlying mechanisms remains poorly understood.This study aimed at examining the neuroprotective properties of EA and its potential mechanism of action against AD.Methods APP/PS1 transgenic mice were employed to evaluate the protective effects of EA on Shenshu(BL 23)and Baihui(GV 20).Chemogenetic manipulation was used to activate or inhibit serotonergic neurons within the dorsal raphe nucleus(DRN).Learning and memory abilities were assessed by the novel object recognition and Morris water maze tests.Golgi staining,western blot,and immunostaining were utilized to determine EA-induced neuroprotection.Results EA at Shenshu(BL 23)and Baihui(GV 20)effectively ameliorated learning and memory impairments in APP/PS1 mice.EA attenuated dendritic spine loss,increased the expression levels of PSD95,synaptophysin,and brain-derived neurotrophic factor in hippocampus.Activation of serotonergic neurons within the DRN can ameliorate cognitive deficits in AD by activating glutamatergic neurons mediated by 5-HT1B.Chemogenetic inhibition of serotonergic neurons in the DRN reversed the effects of EA on synaptic plasticity and memory.Conclusion EA can alleviate cognitive dysfunction in APP/PS1 mice by activating serotonergic neurons in the DRN.Further study is necessary to better understand how the serotonergic neurons-related neural circuits involves in EA-induced memory improvement in AD.

Ca^2＋ in the dorsal raphe nucleus promotes wakefulness via endogenous sleep-wake regulating pathway in the rats

Aim Serotonergic neurons in the dorsal raphe nucleus （DRN） are involved in the control of sleep- wake states. Our previous study indicated that calcium （Ca^2＋ ） modulation in the DRN plays an important role in rapid eye movement sleep （REMS） and non-REMS （NREMS） regulation during pentobarbital hypnosis. Presentstudy was designed to investigate the effects of Ca^2＋ in the DRN on sleep-wake regulation and related neuronal mechanism in freely moving rats. Methods CaC12 （25 or 50 nmol） was microinjected into the DRN and sleep pa- rameters were detective by electroencephalogram （EEG） Monoamine neurotransmitters were detected by HPLC- ECD. c-Fos expression in sleep-wake regulating nucleus was detected by immunohistochemistry. Results Our re- sults showed that microinjection of CaC12 （25 or 50 nmol） into the DRN promoted wakefulness and suppressed NREMS including slow wave sleep （SWS） and REMS in freely moving rats. Meanwhile intro-DRN application of CaC12 （25 or 50 nmol） significantly increased serotonin in DRN and hypothalamus, as well increased noradrenaline in locus coeruleus （LC） and hypothalamus. Immunohistochemistry study indicated that the application CaC12 （25 or 50 nmol） into the DRN significantly increased c-Fos expression ratio in wake-promoting neurons including seroton- ergic neurons in the DRN, noradrenergic neurons in the LC and orxinergic neurons in the perifornical nucleus （Pef） , but decreased c-Fos expression ratio of GABAergic sleep-promoting neurons in the ventrolateral preoptic nu- cleus （VLPO）. Conclusion These results suggest that Ca^2＋ in the DRN exert arousal effects via up-regulation of serotonergic function in endogenous sleep-wake regulating pathways.

Effects of various frequency electrical stimulation of the dorsal raphe nucleus on spontaneous firing activities in the rat subthalamic nucleus

BACKGROUND： Some investigations have demonstrated that exogenous 5-hydroxytryptamine increases the spontaneous firing rate of subthalamic nucleus （STN） neurons in the rat brain. OBJECTIVE： To validate the effect of electrical stimulation to the dorsal raphe nucleus （DRN） on the neuronal activities of the STN in rats, as well as analyze the differences in the effects of electrical stimulation at various frequencies. DESIGN, TIME AND SETTING： Experiments were performed from March 2007 to June 2007 in the Electrophysiology Laboratory of Liaoning Medical University with a randomized controlled animal study design. MATERIALS： Twenty-four healthy male Sprague-Dawley （SD） rats, weighing 250-350 g, were selected for this study. An A320R constant electrical stimulator was purchased from World Precision Instruments Company （USA）; a Spike 2 biological signal acquisition system was purchased from British CED Company. METHODS： Twenty-four SD rats were randomly assigned into a model group and a normal group, with 12 rats in each group. To mimic Parkinson＇s disease, rats in the model group were injected with 4μL of 6-hydroxydopamine into the right striatum, then received deep brain stimulation. Rats in the normal group received deep brain stimulation in same brain region without modeling. Electrical stimulation （width, 0.06 ms; intensity, 0.2-0.6 mA; frequency, 20-130 Hz; train duration, 5 seconds） was delivered to the DRN. MAIN OUTCOME MEASURES： The firing rates of STN neurons were observed by extracellular recording using a biological signal acquisition system. RESULTS： DRN-high-frequency stimulation （DRN-HFS） induced excitation in 59% of the STN neurons in the normal group and 50% of the STN neurons in the model group; mean firing rates increased significantly from （7.14±0.75） and （7.94 ± 0.61） Hz to （11.17 ±1.49） and （12.11 ± 1.05） Hz, respectively （P 〈 0.01）. Spontaneous firing rate increased significantly in 53% of neurons in normal rats in a frequency-dependent manner when stimulation frequency was in the range 80-130 Hz. CONCLUSION： DRN-HFS induced an excitatory effect on the spontaneous activity of STN neurons in both normal and PD rats. There was a frequency-dependent effect of electrical stimulation of the DRN on spontaneous firing activities in STN neurons.

The Role of Dorsal Raphe Nucleus and 5-HT in the Electro-acupunctural Inhibition of the cAMP Induced ECoG Epileptiform Activities in Rabbits

Like electroacupuncture (EA),electrical stimulation of the dorsal raphe nucle-us (DRN)also inhibits the cAMP induced cortical epileptic waves and the EA inducedinhibition can be abolished or markedly reduced by iv cyproheptadine (CYP) or destruc-tion of DRN by electrolysis.The results suggest that 5-HT neurons in the DRN mayplay an important role in the EA inhibition of the generation of cAMP induced elec-trocorticogram (ECoG) epileptic waves.

Distributive characteristics of projection from vestibular nuclei to nucleus raphe magnus in rats

BACKGROUND： Morphological studies have confirmed that vestibular nuclei accepts serotoninergic projections from nucleus raphe magnus, nucleus raphes pallidus, etc. But it is still unclear whether there is bi-directional association between vestibular nuclei and nucleus raphe magnus. OBJECTIVE： To observe the characteristics of projective fibers from vestibular nuclei to nucleus raphe magnus using tetramethyl rhodamine （TMR） in rats, so as to provide more sufficient morphological evidence of neural association from vestibular nuclei. DESIGN： An observational experiment. SETTING： Department of Anatomy （K.K. Leung Brain Research Center）, the Fourth Military Medical University of Chinese PLA. MATERIALS： Eighteen male SD rats of clean degree, weighing 250-280 g, were provided by the Experimental Animal Center of the Fourth Military Medical University of Chinese PLA. METHODS： The experiments were carried out in the laboratory of Department of Anatomy （K.K. Leung Brain Research Center）, the Fourth Military Medical University of Chinese PLA from September 2006 to January 2007. All the rats were anesthetized with intraperitoneal injection of pentobarbital sodium, then according to the coordinates on the rat brain atlas, 0.1 μL TMR （100 g/L） was injected into nucleus raphes magnus via the tip of glass microtubule by means of microinjection. Seven days later, the rats were anesthetized, then perfused and fixed to remove brain, and then frozen coronal brain sections were prepared. The retrogradely labeled neurons in the injected and projected sites were observed under fluorescence microscope. Light filters with evoked wave length of 540-553 nm and emission wave length ≥ 1 580 nm were selected to observe the orange TMR-labeled neurons. All the sections were observed and counted under the fluorescence microscope. MAIN OUTCOME MEASURES： Characteristics and number of retrogradely labeled neurons at different sites of nuclei. RESULTS： Totally 18 SD rats were enrolled, 9 of them were excluded due to the deviation of injected site, and the other 9 were involved in the final analysis of results. The concentrated region of TMR injection was mainly restricted to nucleus raphes magnus, and diffused to the surrounding area to different extents. There were obvious differences in the distributions of the labeled neurons among the subdivisions in vestibular nuclei, as well as the distributions of the labeled neurons at different sites in the same subdivision. The majority of the labeled neurons distributed in the rostral levels of medial vestibular nucleus and the lateral vestibular nucleus, while fewer labeled neurons were observed in superior vestibular nucleus. CONCLUSION： ① There might be bi-directional association between vestibular nucli and nucleus raphe magnus, suggesting that nucleus raphe magnus played a role in the transmission and processing of vestibular information. ② The projection from nucleus raphe magnus to vestibular nucleus has certain distributive characteristics in the region.

Congenital median raphe cysts: Coexistence of cystic lesions and canal-like lesions

Median raphe cyst of the perineum is a rare congenital anomaly and was first reported in 1895. We report a 9-year-old male with median raphe cysts in the perineum which had become swollen and then spontaneously ruptured several times since he was 3 years old. There were two separate lesions;one was a cystic lesion and the other was a canal-like lesion. They were completely excised and the inner layer of the cysts was composed of transitional epithelium.

THE ROLE OF NUCLEUS RAPHE MAGNUS IN THE ANTINOCICEPTIVE EFFECT OF MUSCLE SPINDLE AFFERENTS IN THE RAT

Objective To investigate the role of NRM in the antinociceptive effect of muscle spindle afferents,the influence of NRM lesion on the inhibitory effect of muscle spindle afferents on the nociceptive responses of wide dynamic range (WDR) neurons and the effects of the muscle spindle afferents on the NRM neuronal activities were observed. Methods The single units of WDR neurons in the spinal dorsal horn were recorded extracellularly, and the inhibitory effects of activating muscle spindle afferents by intravenous administration of succinylcholine (SCH) on the C fibers evoked responses (C responses) of WDR neurons were tested before and after lesion of NRM.The effects of the muscle spindle afferents activated by administrating SCH on the single NRM neurons were also examined.Results ①It was found that the C responses of WDR neurons were significantly inhibited by intravenously administration of SCH, and the inhibitory effect was reduced after lesion of NRM;②The activities of most of the NRM neurons could be changed significantly by administrating SCH. According to their responses, NRM neurons could be classified into three types:excitatory, inhibitory and non responsive neurons, and the responses were dose dependent. Conclusion These results suggest that the muscle spindle afferents evoked by SCH may activate the NRM neurons, which plays an important role in the antinociception of muscle spindle afferents.

Oxytocin in rat nucleus raphe magnus influences pain modulation

The main function of Nucleus raphe magnus (NRM) is mostly pain mediation. Our previous study has demonstrated that oxytocin (OXT) regulates antinociception through the central nervous system rather than the peripheral organs, and pain stimulation increases OXT concentration in the NRM. The experiment was designed to investigate OXT in the rat NRM effect on pain modulation. The results showed that 1) pain stimulation increased OXT concentration in NRM perfusion liquid;2) Intra-NRM microinjection of OXT increased the pain threshold in a dose-dependent manner, whereas intra-NRM microinjection of OXT receptor antagonist, desGly-NH2, d(CH2)5[D-Tyr2, Thr-sup-4]OVT decreased the pain threshold;3) NRM pre-treatment with OXT receptor antagonist completely attenuated the pain threshold increase induced by intra-NRM administration of OXT. The data suggested that OXT in NRM was involved in antinociception via OXT receptors.

Activation of angiotensin Ⅱ type 1 receptors in the median preoptic nucleus induces a diuretic and natriuretic response in rats

Objective： To investigate the effect of activation of angiotensin Ⅱ（AngⅡ） type 1 （AT1） receptors in the median preoptic nucleus （MnPO） of rats on renal sodium excretion. Methods： After anesthesia, the rats were injected into the MnPO via an implanted cannula. Urine samples were collected via a bladder cannula, and the urine sodium concentration was assayed with flame spectrophotometry. The serum level of endogenous digitalis-like factor （EDLF） and Na^＋,K^＋-ATPase activity in the renal cortex tissue were assayed respectively with a radioimmunoassay and with an ammonium molybdophosphate-based kit. Results： Both the urinary volume and the sodium excretion peaked 60 min after AngⅡ was administered into the MnPO. The responses were accompanied by an increase in serum EDLF and a decrease in Na^＋,K^＋-ATPase activity in the renal cortex. The responses of diuresis and natriuresis, as well as an increase in serum EDLF and a decrease in Na^＋,K^＋-ATPase activity in the renal cortex induced by MnPO adminstration with AngⅡ were inhibited by pior treatment with the AngⅡ receptor blocking agent losartan into the MnPO. Conclusion： These results suggest that activation of AT1 receptors in the MnPO of rat induces diuretic and natriuretic responses. The responses are associated with an increase release of EDLF and with the inhibition of Na^＋,K^＋-ATPase activity in renal cortex tissue.

大鼠中缝背核及中缝正中核内的VIP、GABA样触液神经元

本文将ＣＢ－ＨＲＰ注入侧脑室，用ＣＢ－ＨＲＰ逆行迫踪与免疫细胞化学相结合的方法，对大鼠脑干内的中缝背核及中缝正中核的远位触液神经元进行了定性研究。结果表明：中缝背核内存在ＶＩＰ样、ＧＡＢＡ样免疫反应阳性的触液神经元；中缝正中核内亦存在少量ＶＩＰ样、ＧＡＢＡ样免疫反应阳性触液神经元。它们的形态和数量各异。本文首次报道中缝背核和中缝正中核内远位触液神经元的化学性质，为探索其机能意义提供了形态学依据。

人参皂甙对急性肾衰大鼠中缝正中核和中缝背核5-HT含量的影响

目的:本研究选用甘油致急性肾衰(ARF)动物模型,探讨口服人参皂甙(GS)对ARF大鼠中缝正中核(MRN)和中缝背核(DRN)5-羟色胺(5-HT)含量变化的影响。方法:64只健康雄性SD大鼠,随机分为4组:模型组、模型给药组、空白对照组和空白给药组。肌肉注射甘油制备急性肾衰模型,利用商品化试剂盒检测口服人参皂甙48h后各组大鼠血尿素氮(BUN)和肌酐(Cre)的变化;同时用免疫组化方法观察MRN和DRN5-HT免疫反应活性(5-HT-IR)变化。结果:肾功能检测显示模型对照组血清BUN和Cre水平显著升高,模型给药组血清BUN和Cre水平显著下降。免疫组化的实验显示ARF大鼠MRN5-HT-IR增强,DRN5-HT-IR减弱;人参皂甙能明显阻断ARF诱导的上述变化。结论:人参皂甙处理能够减少ARF大鼠MRN5-HT含量,增加DRN5-HT的含量,人参皂甙对MRN和DRN内5-HT能神经元活性的差异调节可能是人参皂甙抗急性肾衰和保护肾功能的中枢神经元机制之一。

阴茎中脊囊肿的形态学观察

目的 观察阴茎中脊囊肿临床病理及免疫组织化学特点 ,探讨其发生机理。方法 3例阴茎中脊囊肿患者切除标本进行常规HE染色及免疫组织化学染色。一抗分别为CK7,CK13,CK2 0 ,EMA ,CEA ,Vimentin ,CgA ,Syn)。结果 所有 3例患者均以龟头形态异常就诊 ,囊肿均位于尿道外口旁。 3例患者囊肿被覆上皮均为尿道上皮及其化生上皮。免疫组织化学上皮细胞Keratin (CK7 ,CK13 ,CK2 0 - ) ,EMA +,CEA +,Vimentin - ,CgA - ,Syn -。结论 阴茎中脊囊肿可能起源于尿道外口旁外部导管来源的尿道上皮及其化生上皮 ,与胚生殖沟发育障碍有关。

P物质和亮-脑啡肽样免疫反应神经元在鼠中脑中缝核的分布

本实验采用PAP免疫细胞化学技术,观察P物质和亮-脑啡肽样免疫反应神经元在鼠中脑中缝核的分布并作了计数。1.含P物质样免疫反应神经元胞体仅见于中缝背核最尾侧部,含P物质阳性胞体数平均167个/只;而亮-脑啡肽样免疫反应胞体几乎遍于中缝背核全长,其阳性胞体数平均132个/只。2.亮-脑啡肽样免疫反应胞体主要定位于中缝背核中线区;而P物质样免疫反应胞体除分布于中缝背核中线区以外,也定位在其两侧的延伸。3.亮-脑啡肽样免疫反应胞体恒定地出现在中缝正中核内,平均199个/只;而P物质样免疫反应胞体仅见于2例动物。4.中缝背核内有些含P物质样免疫反应阳性胞体或突起,紧邻血管壁排列,未观察到亮-脑啡肽样免疫反应神经元有类似现象。本实验观察到鼠中缝正中核内存在含P物质样免疫反应神经元胞体。

模拟脑电节律的调制磁场对中缝核神经元放电影响的研究

用数值计算和动物实验的方法研究模拟脑电节律的调制磁场对与睡眠有关的中缝核神经元放电的影响 ,从而探讨其对睡眠的影响。通过数字仿真 ,研究了神经纤维对调制磁场刺激作用的响应特性 ,发现了神经纤维具有对低频调制包络信号响应敏感 ,对高频载波不响应的特性。依据睡眠全过程脑电节律的变化 ,研制了模拟 EEG信号发生器。采用高频磁脉冲作为载波调制模拟脑电节律信号 ,用所得的调制磁场诱导兔脑 ,观察磁刺激对中缝核5 -羟色胺能神经元放电的影响。动物实验结果表明 ,中缝核经磁刺激后放电频率发生显著改变 ,其放电变慢。这说明磁刺激能抑制 5 -羟色胺能神经元神经电活动水平 。

豚鼠中脑中缝背核和中缝正中核5-羟色胺能神经元向视交叉上核的直接投射

实验借助HRP逆行定位和免疫细胞化学定性相结合的双重标记技术,探讨豚鼠中脑中缝背核和中缝正中核向下丘脑视交叉上核的直接投射.结果首次确定了:(1)中缝背核/中缝正中核内5-羟色胺和非5-羟色胺能神经元对视交叉上核的直接投射和分布特点;(2)投射神经元主要集中在中缝背核;(3)中缝背核对视交叉上核的投射神经元几乎均为5-羟色胺能,而中缝正中核中5-羟色胺和非5-羟色胺能投射神经元约各占半数.

阴茎中线囊肿2例

报道2例阴茎中线囊肿。2例患者(18岁,25岁)分别于1年前及2年前发现阴茎包皮系带旁囊样肿物,无特殊不适,渐增大。病理检查示:表皮正常,真皮内见囊肿,囊壁为假复层上皮。

VGLUT3 neurons in median raphe control the efficacy of spatial memory retrieval via ETV4 regulation of VGLUT3 transcription

The raphe nucleus is critical for feeding, rewarding and memory. However, how the heterogenous raphe neurons are molecularly and structurally organized to engage their divergent functions remains unknown. Here, we genetically target a subset of neurons expressing VGLUT3. VGLUT3 neurons control the efficacy of spatial memory retrieval by synapsing directly with parvalbumin-expressing GABA interneurons(PGIs) in the dentate gyrus. In a mouse model of Alzheimer's disease(AD mice),VGLUT3→PGIs synaptic transmission is impaired by ETV4 inhibition of VGLUT3 transcription. ETV4 binds to a promoter region of VGLUT3 and activates VGLUT3 transcription in VGLUT3 neurons. Strengthening VGLUT3→PGIs synaptic transmission by ETV4 activation of VGLUT3 transcription upscales the efficacy of spatial memory retrieval in AD mice. This study reports a novel circuit and molecular mechanism underlying the efficacy of spatial memory retrieval via ETV4 inhibition of VGLUT3 transcription and hence provides a promising target for therapeutic intervention of the disease progression.

Effects of 5-hydroxytryptamine ascending pathways of dorsal raphe nuclei and habenular nucleus on the respiration and blood pressure of rats

Obstructive sleep apnea syndrome （OSAS） was a disease of breath obstacle happened in the process of sleep. The central mechanism of OSAS has not yet been fully elucidated. Most of studies focused on raphe nuclei and 5-hydroxytryptamine （5-HT）, and showed that brain serotonergic activity might be decreased in OSAS. It is well known that the dorsal and medial raphe nuclei provide almost all the serotonergic innervation to the forebrain. A previous study evaluated the stimulation of the dorsal raphe nuclei （DRN） in the rat inducing mainly pressor and sympathoexcitatory responses.

促生长素抑制素样免疫反应在大白鼠弓状核和正中隆起的超微结构分布

本文用免疫电镜方法证明:促生长素抑制素样免疫反应神经末梢分布于弓状棱并与未标记的树突形成轴树突触。在正中隆起的纤维层和栅状层内均可见上述免疫反应末梢,大多数紧贴门脉毛细血管基底膜周围甚至穿入基底膜内。免疫反应末梢尚可与未标记的末梢形成轴轴突触样结构。

中缝正中核的功能研究进展

中缝正中核(MRN)是中缝核群的主要核团之一,细胞数量和类型众多,涉及的神经环路范围广泛,功能非常复杂。近年来的研究发现其可能参与情绪、记忆形成与提取、睡眠-觉醒以及成瘾等过程的调节。本文围绕近年来对中缝正中核的功能研究进展进行综述,以期为后续研究提供参考。