电刺激小脑顶核对主要心血管生理参数的影响

目的:本文通过研究电刺激小脑顶核对光电容积脉搏波的影响,探讨电刺激小脑顶核对于人体心血管系统产生的生理效应。方法:记录30位受试者在小脑顶核受刺激时的脉搏波数据,提取了上升支主波幅度H、上升沿斜率Slope、脉搏波波形特征量K值等5种波形特征值。对比分析在刺激中和刺激前后各特征值的变化并根据该变化描述电刺激小脑顶核所引起的生理变化。结果:电刺激小脑顶核使脉搏波呈现出灵敏的一过性变化。结论:特征值的变化反应出电刺激小脑顶核使外周血流量、外周阻力等生理参数发生了一过性的变化。     

Filtering of deep sequencing data reveals the existence of abundant Dicer-dependent small RNAs derived from tRNAs

Deep sequencing technologies such as Illumina, SOLiD, and 454 platforms have become very powerful tools in discovering and quantifying small RNAs in diverse organisms. Sequencing small RNA fractions always identifies RNAs derived from abundant RNA species such as rRNAs, tRNAs, snRNA, and snoRNA, and they are widely considered to be random degradation products. We carried out bioinformatic analysis of deep sequenced HeLa RNA and after quality filtering, identified highly abundant small RNA fragments, derived from mature tRNAs that are likely produced by specific processing rather than from random degradation. Moreover, we showed that the processing of small RNAs derived from tRNA^Gln is dependent on Dicer in vivo and that Dicer cleaves the tRNA in vitro.     

小脑-下丘脑投射在小脑顶核调节淋巴细胞数量与功能中的介导作用

目的:探讨小脑顶核对淋巴细胞功能的调节作用及其作用途径。方法:用海人酸(KA)损毁大鼠双侧小脑顶核,术后第8d用血细胞计数法和酶联免疫吸附试验(ELISA)分别检测动物外周血中淋巴细胞数和血清中抗绵羊红细胞(SRBC)特异性IgM抗体水平。用电损毁小脑上脚交叉中顶核投射至下丘脑的神经纤维,检测动物淋巴细胞数和抗SRBC特异性IgM抗体水平的变化。结果:KA注入双侧小脑顶核后第8d,在Nissl染色的小脑切片,呈现双侧顶核内神经元胞体破坏。作为对照,在生理盐水注入顶核的动物脑片上,可见正常的Nissl小体。小脑顶核损毁后第8d,动物外周血中淋巴细胞数占白细胞总数的百分比以及血清中抗SRBC特异性IgM抗体水平均明显高于顶核注射生理盐水的对照动物。电损毁小脑上脚交叉处顶核投射至下丘脑的神经纤维后第8d,外周血中淋巴细胞的百分比及抗SRBC特异性IgM抗体水平均明显高于假损毁小脑上脚交叉的对照动物。结论:小脑顶核的神经元胞体损毁导致淋巴细胞功能增强,小脑顶核投射至下丘脑的神经纤维损毁同样引起淋巴细胞功能增强,这些结果提示小脑顶核至下丘脑的神经投射参与介导小脑顶核对淋巴细胞功能的调节作用。     

Background impulse activity of neurons of the fastigial cerebellar nucleus of intact and labyrinthectomized rats under conditions of vibration

In acute experiments on nembutal-anesthetized (40 mg/kg, i.p.) albino rats, we recorded extracellularly and analyzed the background impulse activity (BIA) of neurons of the fastigial nucleus of the cerebellum. Experiments were carried out on intact and labyrinthectomized rats in the norm and after long-lasting (up to 15 days) influence of general vertical vibration (60 Hz, 0.4 mm, 2-h-long everyday sessions). Distributions of the neurons according to the level of regularity of BIA, dynamics of spike trains, pattern of histograms of interspike intervals (ISIs), and different frequency ranges of BIA were plotted; the mean frequency of this activity and the coefficient of variation of ISIs were also calculated. Possible mechanisms of the effects of long-lasting vibration of different durations on the BIA generated by neurons of the fastigial cerebellar nucleus in intact animals and after switching off of labyrinth afferent inputs are discussed. Neirofiziologiya/Neurophysiology, Vol. 38, No. 1, pp. 32–39, January–February, 2006.     

电刺激大鼠蓝斑核区对实验性急性心肌缺血性损伤的影响

本实验在大鼠尾静脉注射垂体后叶素造成急性心肌缺血性损伤,以心电图肢体导联 S-T_Ⅱ段和 T_Ⅱ以及心率为指标,观察了电刺激蓝斑核区对大鼠急性心肌缺血性损伤的影响。实验结果表明蓝斑核区电刺激组的缺血性心电图恢复时间与对照组相比显著提前,前者为18.8±8.31分,后者为67±12.74分(P<0.01)。脑非蓝斑核区电刺激组的缺血性心电图恢复时间为69.2±6.8分。蓝斑核埋藏电极组的恢复时间为44.5±9.97分,与蓝斑核区电刺激组相比,其差异均非常显著(P<0.01)。这些结果说明蓝斑核区的刺激对大鼠急性心肌缺血性模型的恢复有促进作用。     

深部脑刺激对大鼠丘脑底核神经活动的影响

为了探求高频电刺激对受刺激核团的影响,在高频刺激丘脑底核的同时,同步记录了大鼠丘脑底核神经元活动．针对同步记录中刺激伪迹的难题,研究并应用了高效的刺激伪迹滤出算法,恢复了被掩盖的神经响应,且失真小．研究了刺激幅度、频率与神经元神经响应类型的关系,以及在临床治疗有效刺激参数下,高频刺激对神经元平均放电率的影响．研究结果显示,放电率的变化可能与帕金森症病理状态无直接关系,爆发式放电增多更可能是帕金森发病潜在的电生理基础,而受刺激核团的自发放电的抑制、放电率的降低及爆发式放电的减少则有可能是深部脑刺激作用机制的一部分．     

Neurogenic Neuroprotection

1. Stimulation of the rostral-ventromedial pole of the cerebellar fastigial nucleus exerts powerful effects on systemic and cerebral circulation.2. Excitation of fibers passing through the fastigial nucleus evokes sympathoactivation and increases in arterial pressure.3. Increase in cerebral blood flow evoked by excitation of fibers passing through the FN is mediated by intrinsic brain mechanisms independently of metabolism.4. Excitation of the fastigial nucleus neurons in contrast decreases arterial pressure and cerebral blood flow. The latter probably is secondary to the suppression of brain metabolism.5. Excitation of the fastigial nucleus neurons significantly decreases damaging effects of focal and global ischemia on the brain.6. The fastigial nucleus-evoked neuroprotection can be conditioned: 1-h stimulation protects the brain for up to 3 weeks.7. Other brain structures such as subthalamic cerebrovasodilator area and dorsal periaqueductal gray matter also produce long-lasting brain salvage when stimulated.8. More than one mechanism may account for neurogenic neuroprotection.9. Early neuroprotection, which develops immediately after the stimulation, involves opening of potassium channels.10. Delayed long-lasting neuroprotection may involve changes in genes expression resulting in suppression of inflammatory reaction and apoptotic cascade.11. It is conceivable that intrinsic neuroprotective system exists within the brain, which renders the brain more tolerant to adverse stimuli when activated.12. Knowledge of the mechanisms of neurogenic neuroprotection will allow developing new neuroprotective approaches.     

研究报告: 模拟航天失重病理特征的小鼠模型的制备

目的 航天员返回地球后常常出现共济失调、步态紊乱,是航天医学难题。急需制备一种符合航天失重导致运动失调病理特征的小鼠,为药物筛选提供新模型。方法 将雄性C57BL/6J小鼠随机分成：a.对照组,野生健康成年小鼠;b.标准模型组-后肢悬吊组（hindlimb unloading,HU）,按照常规方法建立后肢悬吊法模型;c.假手术组（顶核注射磷酸缓冲液组）;d.模拟病理特征模型组（顶核注射甲醛组）,该组利用立体定位向健康成年雄性小鼠的小脑顶核内微量注射病理浓度的甲醛（尾吊组脑部测得的浓度）。造模结束后用转棒、平衡木、步态分析来评估小鼠的运动能力、小脑切片尼氏染色检测顶核神经元死亡、试剂盒及荧光组化检测甲醛生成酶——氨基脲敏感胺氧化酶（semicarbazide-sensitive amine oxidase,SSAO）活性及表达。用甲醛荧光探针检测小脑顶核的甲醛浓度。结果 后肢悬吊组相较对于对照组的小鼠运动平衡能力下降、步态紊乱,并伴随小脑内SSAO活性及表达增强、内源甲醛显著上升、顶核神经元死亡。其次,模拟病理特征组小鼠的顶核注射病理浓度甲醛注射后,也出现尾吊标准模型类似的生化及行为变化...     

Electrical stimulation of cerebellar fastigial nucleus protects rat brain, in vitro, from staurosporine-induced apoptosis

Electrical stimulation of the cerebellar fastigial nucleus (FN) elicits a prolonged ( approximately 10 days) and substantial (50-80%) protection against ischemic and excitotoxic injuries. The mechanism(s) of protection are unknown. We investigated whether FN stimulation directly protects brain cells against apoptotic cell death in an in vitro rat brain slice culture model. Rats were electrically stimulated in FN or, as control, the cerebellar dentate nucleus (DN). Coronal slices through the forebrain were explanted, exposed to staurosporine, harvested, and analyzed for caspase-3 activity by a fluorescence assay. FN, but not DN, stimulation significantly reduced staurosporine-induced caspase-3 activity by 39 +/- 7% at 3 h, 31 +/- 3% at 6 h and 26 +/- 4% at 10 h of incubation. Immunocytochemistry revealed FN-specific reductions in activated caspase-3 mainly in glial-like cells throughout the forebrain. FN stimulation also results in a 56.5% reduction in cytochrome c release upon staurosporine incubation. We conclude that neuroprotection elicited from FN stimulation can directly modify the sensitivity of brain cells to apoptotic stimuli and thereby suppress staurosporine induced apoptosis in adult rat brain slices. This model indicates that neuroprotection can be studied in vitro and provides new insight into the potential role of glial cells in ischemic protection of neurons induced by FN stimulation.     

Identification and comparative analysis of the miRNA expression profiles from four tissues of Micropterus salmoides using deep sequencing

In the present study, four small RNA libraries were constructed from an M. salmoides population and sequenced using deep sequencing technology. A total of 9,888,822; 8,519,365; 20,566,198; and 15,762,254 raw reads representing 666,097; 755,711; 978,923; and 840,175 unique sequences were obtained from the spleen, liver, kidney, and muscle libraries, respectively. As a result, 509 known miRNAs belonging to 143 families and 1157 novel miRNAs were identified. The miRNAs displayed diverse expression levels among the four libraries, among which most of the known miRNAs were expressed at higher levels than the novel miRNAs. Furthermore, stem-loop qRT-PCR was applied to validate and profile the expression of the differentially expressed miRNAs in the four different tissues, which revealed that some miRNAs showed tissue specific expression. The identification of miRNAs in M. salmoides will provide new information and enhance our understanding of the functions of miRNAs in regulating biological processes.     

Mitochondria are involved in the neurogenic neuroprotection conferred by stimulation of cerebellar fastigial nucleus

Activation of neural pathways originating in the cerebellar fastigial nucleus (FN) protects the brain from the deleterious effects of cerebral ischemia and excitotoxicity, a phenomenon termed central neurogenic neuroprotection. The neuroprotection is, in part, mediated by suppression of apoptosis. We sought to determine whether FN stimulation exerts its anti-apoptotic effect through mitochondrial mechanisms. Mitochondria were isolated from the cerebral cortex of rats in which the FN was stimulated for 1 h (100 microA; 1 s on/1 s off), 72 h earlier. Stimulation of the dentate nucleus (DN), a brain region that does not confer neuroprotection, served as control. Mitochondria isolated from FN-stimulated rats exhibited a marked increase in their ability to sequester Ca2+ and an increased resistance to Ca2+-induced membrane depolarization and depression in respiration. FN stimulation also leads to reduction in the release in cytochrome c, induced either by Ca2+ or the mitochondrial toxin mastoparan. Furthermore, in brain slices, FN stimulation reduced the staurosporine-induced insertion of the pro-apoptotic protein Bax into the mitochondria, a critical step in the mitochondrial mechanisms of apoptosis. Collectively, these results provide evidence that FN stimulation protects the mitochondria from dysfunction induced by Ca2+ loading, and inhibits mitochondrial pathways initiating apoptosis. These mitochondrial mechanisms are likely to play a role in the neuroprotection exerted by FN stimulation.     

电刺激大鼠束旁核对底丘脑核和丘脑腹内侧核神经元的影响

本工作旨在探讨电刺激束旁核（parafascicular nucleus,PF）对帕金森病模型（Parkinson’s disease,PD）大鼠神经行为的改善作用及其机制。成年雄性Sprague—Dawley大鼠黑质致密部注射6一羟基多巴胺建立PD大鼠模型。采用行为学方法观察电刺激PF对阿朴吗啡诱发的大鼠旋转行为的作用,并应用在体细胞外记录法观察电刺激PF对大鼠底丘脑核（subthalamic nucleus,STN）及丘脑腹内侧核（ventromedial nucleus,VM）神经元放电的影响。结果发现,高频电刺激（130Hz,0．4mA,5s）PF一周,明显改善PD大鼠旋转行为。细胞外放电记录显示,高频电刺激PF使PD大鼠STN神经元自发放电减少,且该作用具有频率依赖性。另外,高频电刺激PF可使VM神经元兴奋,该作用也是频率依赖性的。我们在实验中同时观察到微电泳谷氨酸（glutamicacid,Glu）受体拮抗剂MK-801使STN神经元放电频率减少或完全抑制,微电泳t氨基丁酸（T-amino butyricacid,GABA）受体拮抗剂印防己毒素（picrotoxin,Pic）则使神经元放电频率增加。以上结果表明,GABA能和GIu能传入纤维可会聚于同-STN神经元,并对后者有紧张性作用。高频刺激PF,使该核团到STN神经元的Glu能兴奋性输出减少,导致STN的失活。这一作用通过基底神经节的间接通路,最终释放了丘脑运动核团VM的活性。高频刺激PF经PF,STN和VM的神经通路而改善PD大鼠神经行为。