电刺激大鼠小脑顶核对下丘脑神经元放电活动的影响

目的:研究电刺激小脑顶核(fastigial nucleus,FN)及微电泳Glu(glutamic acid)、MK-801对大鼠下丘脑(hypothalamus,HT)神经元自发放电活动的影响,探讨电刺激FN治疗脑卒中大鼠的机制。方法:应用细胞外记录的方法,记录电刺激FN及微电泳药物对HT神经元放电的影响。结果:电刺激频率为20Hz(低频)时,50%的HT神经元的放电频率增高(P0.01),电刺激频率为100Hz(高频时),80%的HT神经元的放电频率增高(P0.01);Glu对HT有紧张性兴奋作用,其拮抗剂MK-801能够明显抑制Glu诱致的兴奋作用;70%HT神经元在微电泳MK-801的基础上进行100Hz电刺激FN时,高频刺激诱发的兴奋作用被明显削弱。结论:采用电刺激FN治疗脑卒中,其可能机制是通过Glu的兴奋作用来调节HT的异常活动。     

电刺激大鼠下丘脑室旁核对胃缺血-再灌注损伤的影响

采用夹闭大鼠腹腔动脉30min，松开动脉夹血流复灌1h的胃缺血－再灌注损伤模型，观察了电刺激和电损毁下丘脑室旁核（paraventricular nucleus,PVN)对大鼠胃缺血－再灌注损伤（gastric ischemia-reperfusion injury,GI-RI的影响，并对其作用机制进行了初步探讨。结果表明：电刺激PVN后GI－RI显著减轻，且有强度－效应依赖关系；PVN内注射胞体兴奋剂L－谷氨酸后，与电刺激PVN的效应相同；电解损毁双侧PVN则能加重GI－RI；电刺激PVN能显著降低GI－RI大鼠的胃粘膜丙二醛（MDA）含量及胃液酸度和胃蛋白酶活性，但对其超氧化物歧化酶（SOD）的活性及胃液量、总酸排出量、胃整结合粘液量无显著影响。提示PVN对GI－RI具有保护作用，其作用机制可能与降低GI－RI大鼠的胃粘膜MDA含量、胃蛋白酶活性、胃液酸度有关，而与胃液量、总酸排出量、胃壁结合粘液量等因素无明显关系。     

电刺激大鼠伏隔核对腹侧苍白球神经元自发放电的影响

目的:研究电刺激大鼠伏隔核(nucleus accumbens,NAC)对腹侧苍白球(ventral pallidum,VP)神经元放电的影响,探索电刺激NAC治疗药物成瘾的机制。方法:本实验应用细胞外记录方法观察不同频率电刺激(强度0.4mA,波宽0.06ms,时程5s,频率5,10,20,50,80,100,130,150和200Hz)大鼠NAC对VP神经元放电的影响。结果:刺激频率低于20Hz时,大多数VP神经元的放电频率无变化,电刺激频率大于20Hz可使大多数VP神经元的放电频率降低。结论:本研究提示高频刺激NAC对药物依赖可能有治疗作用。     

大鼠下丘脑腹内侧核与杏仁皮质内侧核间电生理的年龄性变化

本实验用双极电极刺激下丘脑腹内侧核（ＶＭＨ），以杏仁皮质侧核（ＡＣｏ）诱发反应为指公检法，观察不同年龄大鼠ＶＭＨ与ＡＣＯ之间联系的变化。结果发现，诱发反应的潜伏期年龄的关系不大；用逆行性诱发反应占总反应的百分数作为指标，中老年组均较青年组明显减少（Ｐ〈０．０１）；刺激ＶＭＨ，在ＡＣ出诱发反应的坐标深度分布有年龄依赖性改变。表现ＶＭＨ与ＡＣＯ之间投射纤维的传导速度受年龄的影响不大，但随年龄的增加，Ａ     

芍药甙对离体大鼠下丘脑腹内侧核神经元电活动的影响

目的:研究芍药甙(PF)对正常大鼠下丘脑腹内侧核(VMH)神经元兴奋性的影响.方法:应用脑片全细胞膜片钳技术记录了35个正常的VMH神经元的自发放电,观察PF对它们的作用.结果:[1]当脑片用含PF(300μmol/L)的人工脑脊液灌流后,有22个神经元放电频率明显减少,平均放电频率从(7.1±2.2)Hz减少到(3.2±0.7)Hz(P＜0.01);在去极化方波刺激下放电数目也明显减少,洗脱后恢复;[2]PF对VMH的葡萄糖受体神经元(GRN)表现为明显的抑制作用,与其对非葡萄糖受体神经元的作用相比,差异有统计学意义(P＜0.01).结论:PF能够降低VMH GRN的放电频率,调节下丘脑饱中枢神经元的兴奋性,从而影响动物的摄食行为.     

刺激家兔面神经核腹内侧区对颏舌肌肌电活动的抑制效应

本研究在 2 6只氨基甲酸乙酯麻醉、断双侧迷走神经的健康成年家兔上观察了电、化学刺激面神经核腹内侧区 (vMNF)对颏舌肌肌电活动的影响。结果如下 :(1)长串电脉冲刺激vMNF导致颏舌肌肌电活动明显被抑制 ;(2 )在vMNF内微量注射谷氨酸钠 ,颏舌肌肌电活动出现明显的抑制效应 ;(3)单脉冲电刺激vMNF引起颏舌肌抑制反应的潜伏期为 (2 0 6± 0 4)ms。结果表明 :vMNF的兴奋能降低颏舌肌的肌电活动 ,从而提示其具有增强上呼吸道阻力的作用。     

催产素对大鼠尾核痛反应神经元放电的影响

实验用Ｗｉｓｔｅｒ大鼠４８只，在尿酯（１．０ｇ／ｋｇ）麻醉下行常规手术，人工呼吸条件下进行实验。用玻璃微电极引导尾核中痛反应神经元（ＰＥＮ、ＰＩＮ）的放电，研究外源、内源催产素（ＯＴ）对其放电的影响。结果：１．尾核内微量注射ＯＴ（０．００５Ｕ／２μ可明显抑制ＰＥＮ放电频率，延长放电潜伏期．可缩短ＰＩＮ放电抑制时时程、增加放电频率。以上放电变化高峰出现在注药后６ｍｉｎ，注药后１５ｍｉｎ恢复，２．电刺     

深部电刺激丘脑底核治疗Parkinson病的机制研究概况

在过去的近20年里,脑深部电刺激(deep brain stimula-tion,DBS)不仅用于运动障碍性疾病的治疗,如原发性震颤、Parkinson病(PD),而且在精神心理疾病的治疗方面,如强迫-冲动综合症、抑郁症等亦取得了一定的成绩。现今,DBS更多地用于重症PD的治疗,常用的刺激靶点有苍白球内侧部(gl     

逆行胃电刺激对健康人水负荷、摄食量和胃排空的影响

目的观察逆行胃电刺激(RGES)对健康人胃容受性、摄食量和胃排空的影响。方法选择健康志愿者12人。沿胃大弯距幽门5 cm处放置一对黏膜电极,以胃动过速的频率9 cyc les/m in,波宽500 m s,强度5 mA的脉冲信号进行RGES。进行水负荷试验、摄食试验和核素闪烁扫描固体胃排空试验来评价RGES的效果。结果与对照阶段相比,RGES可引起摄水量减少13%(P<0.01),摄食减少16%(P<0.001),胃半排空时间延迟33%(P<0.05),120 m in食物存留率增加15%(P<0.05)。水负荷试验、摄食试验和胃排空试验应用的RGES参数没有引起显著症状。结论急性RGES可以显著减少摄水摄食,延缓胃排空,且不引起明显症状。     

电刺激大鼠黑质网状部对脚桥核神经元自发放电的影响

目的:观察电刺激大鼠黑质网状部(substantia nigra pars reticulata,SNr)对脚桥核(pedunculopontine nucleus,PPN)神经元自发放电活动的影响,进一步探讨脑内电刺激治疗帕金森病(Parkinson's disease,PD)的机制.方法:应用细胞外记录方法观察不同...     

Rapid modifications of somatostatin neuron activity in the periventricular nucleus after acute stress

We have previously reported that stress induces a rapid increase in hypothalamic somatostatin (SS) release. In the present work, we investigated whether SS synthesis is also affected by this treatment. Male rats were subjected to 15-min immobilization (IMO) stress, and measurements of both SS mRNA levels and SS mRNA-containing cells were analyzed in the periventricular nucleus (PeV) by radioactive and nonradioactive in situ hybridization (ISH), respectively. In addition, SS content and total SS mRNA were measured in the whole hypothalamus by radioimmunoassay (RIA) and northern blot analysis, respectively. ISH was conducted by applying either a radioactive-labeled (35S) or a digoxigenin (DIG)-labeled oligonucleotide probe on histological sections containing the periventricular region of the anterior hypothalamic area (AHA). ISH analysis using radioactive label showed a significant increase in SS mRNA levels in stressed rats. In contrast, stress treatment decreased the number of DIG-labeled cells expressing SS mRNA in this region by 35% as compared to the same histological sections from naive control rats. In addition, a significant decrease in the total SS mRNA DIG-labeled area was observed. Finally, SS content and SS mRNA measured in the whole hypothalamus of stressed rats were markedly inhibited as compared to control rats. Our data show that IMO stress induces a significant and rapid increase in SS mRNA level accompanied by a decrease in the number of cells expressing SS mRNA in the PeV-AHA. The present results suggest that a subset of PeV SS neurons, which became silent at the onset of stress, are regulated independently of the remaining whole mass of PeV neurons. This differential control is in line with the cellular heterogeneity described in periventricular SS-producing neurons and with the multiple hypothalamic and pituitary functions assigned to SS.     

Changes in spontaneous brain bioelectrical activity during transcranial electrical and electromagnetic stimulation

The systems responses of the brain to therapeutic transcranial electrical and electromagnetic stimulation were studied and the neurophysiological criteria for assessing the efficacy of this treatment were identified using comparative clinical and experimental studies with analysis of spontaneous bioelectrical activity, along with assessment of behavioral and clinical measures. Study groups consisted of six patients with chronic post-traumatic unconscious states during courses of transcranial electrical stimulation and 17 intact Wistar rats subjected to transcranial electromagnetic stimulation. A relationship was found between the effects of transcranial stimulation and the initial level of intercenter interactions of brain bioelectrical activity assessed in terms of coherence. Hypersynchronization of biopotentials, identified as a major element in the reactivity to this type of stimulation, may be of the greatest value in the recovery of patients with cerebral pathology in cases with initially reduced levels of intercenter interactions in the absence of pathologically increased functional connections in the brain. __________ Translated from Zhurnal Vysshei Nervnoi Deyatel’nosti imeni I. P. Pavlova, Vol. 56, No. 3, pp. 363–370, May–June, 2006.     

Ghrelin对糖尿病大鼠下丘脑弓状核胃牵张敏感神经元放电活动及胃运动的调控

 目的：观察链脲佐菌素(STZ)所致糖尿病（DM）大鼠下丘脑弓状核（Arc）胃牵张（GD）敏感神经元放电活动及胃运动改变,探讨ghrelin对DM大鼠下丘脑Arc GD敏感神经元放电活动和胃运动的影响。方法：采用STZ腹腔注射诱导DM大鼠模型;通过细胞外记录神经元单位放电和在体胃运动方法,观察ghrelin及其受体阻断剂［D-Lys3］-GHRP-6对DM大鼠下丘脑Arc GD敏感神经元自发放电活动和胃运动的影响;应用real-time PCR和荧光免疫组化方法,探讨DM大鼠Arc内ghrelin受体（GHS-R1a）mRNA及其免疫阳性物的表达。结果：在正常大鼠Arc记录到的98个GD敏感神经元中,64.3%为GD兴奋性（GD-E）神经元,35.7%为GD抑制性（GD-I）神经元。在63个GD-E神经元中,Arc微量注射ghrelin可使其中73.0%神经元兴奋,其放电频率与生理盐水组比较显著增加（P<0.05）;而在35个GD-I神经元中,Arc微量注射ghrelin可抑制其中60.0%神经元,放电频率显著降低（P<0.01）;ghrelin改变GD神经元放电效应可被ghrelin 受体阻断剂［D-Lys3］-GHRP-6阻断（P<0.05）;在DM大鼠,Arc记录到的66个GD敏感神经元中有56.1%为GD-E神经元,43.9%为GD-I神经元。Arc注射ghrelin可兴奋其中35.1%GD-E神经元,放电频率与生理盐水比较显著增加（P<0.05）;而在29个GD-I神经元中,ghrelin可抑制其中21个神经元（72.4%）,放电频率显著降低（P<0.01）。与正常大鼠比较,DM大鼠Arc GD敏感神经元中的GD-E和GD-I比例无显著改变（P>0.05）,但ghrelin使GD-E神经元兴奋的比率明显降低（P<0.05）,放电频率平均增加率也显著下降（P<0.05）;但ghrelin使GD-I 神经元抑制比率和放电频率平均减少率均无显著改变（P>0.05）。在体胃运动研究结果显示,Arc微量注射ghrelin,可显著促进正常和DM大鼠胃运动,且呈显著量效关系（P<0.05,P<0.01）,但ghrelin对正常大鼠的促胃运动作用显著强于其对DM大鼠的作用（P<0.05）,［D-Lys3］-GHRP-6可完全阻断ghrelin该作用。Real-time PCR研究结果显示,DM大鼠下丘脑Arc GHS-R1a mRNA表达较正常大鼠明显减少（P<0.05）;免疫荧光研究进一步证实DM大鼠下丘脑Arc GHS-R1a 免疫阳性物表达较正常大鼠明显减少（P<0.05）。结论：下丘脑Arc ghrelin参与DM大鼠GD敏感神经元自发放电活动,并参与胃运动的调控,该效应可能是通过作用于ghrelin受体而实现的。     

Comparative quantification of gastric electrical activity and electrogastrograms

The aim of this study was to compare quantitatively the variability of gastric electrical activity (GEA) recorded from asymptomatic patients with implanted serosal electrodes and patients with implanted and cutaneous electrodes. Three pairs of electrodes were inserted into the gastric wall in six patients undergoing laparotomy for other reasons. Normal GEA was assessed visually once patients were tolerating a normal diet. Mean frequency (MF) values of the GEA signal in successive 256 s intervals were obtained. Standard deviations of the MF values for each separate channel of each patient were calculated. Probability density functions (pdfs) of these values were also obtained and compared. 36 1 h simultaneous recordings were made for three patients with implanted and cutaneous electrodes. The recordings were assessed both visually and with computer. A fast Hartley transform was used to obtain the dominant MF values in 256 s time intervals. These values were statistically evaluated for each channel. Normal internal GEA had a mean frequency of 2.5–3.75 cycles min⁻¹ (cpm) and a standard deviation range of 0–0.45 cpm. Bell-shaped pdfs with coinciding maxima were observed in all these recordings, indicating normal electrical coupling. In the comparative 36 h study, using the above definitions of normality, different cutaneous recordings were found to reflect GEA with a sensitivity of 94% and a specificity of 79%.     

Excitatory effects of gastric electrical stimulation on gastric distension responsive neurons in ventromedial hypothalamus (VMH) in rats

INTRODUCTION: Gastric electrical stimulation (GES) has been used for the treatment of obesity with unclear central mechanisms. The purpose of this study was to investigate the effects of GES on the neuronal activity in the ventromedial hypothalamus (VMH). METHODS: Extracellular potentials of single neurons in VMH were recorded in 52 anesthetized rats. Neurons were classified as gastric distension-excitatory (GD-E) neurons or GD-inhibitory (GD-I) neurons. GES with four sets of parameters was applied for comparison. RESULTS: Eighty two neurons out of 96 (85.41%) in VMH responded to gastric distension (GD). 37.8% were GD-E neurons and 51(62.2%) were GD-I neurons. 55.0%, 17.6%, 77.8%, 14.3% of GD-E neurons were excited by four sets of parameters: GES1 (standard), GES2 (reduced pulse numbers), GES3 (increased pulse width) and GES4 (reduced frequency), respectively. More GD-E neurons were excited by GES3 (P < 0.05 versus GES2 or GES4) and by GES1 (P < 0.02 versus GES2 or GES4). Among the GD-I neurons, 63.6, 37.9, 73.3, and 51.9% neurons were excited by GES1-4, respectively. CONCLUSION: GES with parameters used for treating obesity excites GD-responsive neurons in VMH. The excitatory effect of GES is related to the strength of stimulation, including pulse frequency and width as well as pulse train on-time.     

Correlation between noradrenaline content of the brain and the number of granular vesicles in rat hypothalamus during nialamid administration

Summary The fine structure of ventromedial hypothalamic nucleus was studied in the rat with the electron microscope under circumstances of elevated brain monoamine level following treatment with a monoamine oxidase inhibitor Nialamid. The number of granular vesicles (size in diameter 450–1100 Å) in synaptic terminals increased after Nialamid treatment significantly, while their size did not change; the number of agranular vesicles remained unchanged. The time courses of the increase of granular vesicles and elevation of brain noradrenaline content were approximately parallel. It is inferred that the granular vesicles of size 450 to 1100 Å may possibly be the storage sites of noradrenaline.     

Ultrastructural and functional changes in rat brain synaptosomes during electrical stimulation in vitro

Electrical stimulation of a suspension of rat brain synaptosomes leads to significant Ca⁺⁺-dependent liberation of endogenous noradrenalin and to a Ca⁺⁺-dependent increase in its concentration in the synaptosomes themselves. Cyclic nucleotide phosphodiesterase activity is lowered significantly under these same conditions. No disturbance of synaptosomal ultrastructure is found during stimulation. An increase in the number of electron-dense synaptosomes is observed.Laboratory of General Pathology of the Nervous System, Laboratory of Experimental Pathomorphology and Ultrastructural Characteristics of Pathological Processes, Institute of General Pathology and Pathological Physiology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. M. Chernukh.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 89, No. 2, pp. 143–145, February, 1980.     

Recovery of mating behavior in the female rat following VMH lesions.

On the day of proestrus, female rats were given large electrolytic lesions aimed at the ventromedial nucleus of the hypothalamus (VMH). Following a postoperative period of extended diestrus the vaginal smears showed irregular periods of vaginal cornification with a tendency toward prolonged periods of cornified smears. Sexual receptivity, measured in terms of the lordosis-to-mount ratio (L% = L/M X 100) was low on the evening of the first postsurgical proestrus, but improved markedly in subsequent mating sessions. Although the lordosis response was present, the intromission frequency remained below that observed during mating sessions with control females. Findings at autopsy together with the prolonged periods of vaginal cornification suggest that VMH lesions result in blocked or delayed ovulation. The behavioral data contradict previous reports of blocked mating behavior in VMH females based upon indirect measures of receptivity, i.e., the presence of vaginal plugs or sperm on the morning following overnight caging with sexually active males.