内侧隔核胆碱能神经元与GABA能神经元参与慢性神经病理性疼痛

目的:研究内侧隔核(medial septum, MS)内的胆碱能神经元与GABA能神经元对部分神经损伤(spared nerve injury, SNI)导致的大鼠慢性神经病理性疼痛的影响。方法:首先使用192 IgG-saporin(SAP)损毁内侧隔核内的胆碱能神经元,实验大鼠分为两组:假损毁加SNI、SAP损毁加SNI,比较损毁组与对照组大鼠的慢性神经病理性疼痛的变化,以及采用条件位置厌恶评估两组大鼠SNI引起的情绪变化。另外使用海人酸(kainic acid, KA)损毁内侧隔核内的GABA能神经元,实验大鼠分为两组:假损毁对照组加SNI、KA损毁加SNI,比较损毁组与对照组大鼠的神经病理性疼痛的变化。结果:特异损毁内侧隔核胆碱能神经元能明显缓解神经病理性疼痛以及SNI引起的厌恶情绪,而特异损毁内侧隔核内的GABA能神经元也能明显缓解神经病理性疼痛。结论:内侧隔核内胆碱能神经元与GABA能神经元均参与神经病理性疼痛。     

慢性坐骨神经结扎神经痛大鼠脊髓nNOS阳性神经元的表达

目的:探讨慢性坐骨神经结扎(CCI)神经病理性疼痛大鼠脊髓背角nNOS阳性神经元的表达。方法:SD大鼠40只,随机分为五组,每组8只,即naive组、sham组、CCI5d组、CCI10d组;CCI15d组;测定各组大鼠机械缩腿阈值(MWT)和热缩腿潜伏期(TWL);同时sham组大鼠在术后5d、CCI各组分别在术后5d、10d、15d断头处死取脊髓腰膨大,采用免疫组化法测定脊髓背角nNOS阳性神经元的表达。结果:CCI大鼠在手术后形成稳定的痛敏,与naive组和sham组大鼠比较有显著差异;naive组大鼠和sham组大鼠脊髓背角仅见少量nNOS阳性神经元的表达,且两组间无统计学意义;CCI各组大鼠脊髓背角nNOS阳性神经元的表达明显增多,与naive组和sham组比较差异显著。结论:慢性坐骨神经结扎(CCI)神经痛大鼠脊髓背角nNOS阳性神经元的表达增加,脊髓背角nNOS可能参与了CCI大鼠神经病理性疼痛的形成。     

神经病理性疼痛大鼠脊髓中星形胶质细胞GFAP及FGFRs不同表达的观察

目的:观察神经病理性疼痛(neuropathic pain,NP)大鼠脊髓成星形胶质细胞(Glial fibrillary acidic protein,GFAP)以及纤维生长因子受体家族成员1~4(fibroblast growth factor receptor 1~4,FGFR1~4)的表达变化。方法:体重180~200g的SD雄性大鼠40只随机分为2组(n=20),分别制作模型:假手术组(sham)和模型组(SNI)。术后1,3,5,7天使用von Frey纤维针测量大鼠术侧机械痛域值(mechanical pain threshold,MPT),并在相应的时间点取各组大鼠L4~L6脊髓,使用激光共聚焦检测脊髓背角星形胶质细胞GFAP表达水平以及激活状态,实时荧光定量PCR检测GFAP mRNA、FGFRs mRNA表达水平的变化情况。结果:与sham组相比,SNI组大鼠痛域值随时间下降明显,脊髓星形胶质细胞GFAP阳性细胞数和GFAP mRNA表达从术后3天起逐渐升高。FGFRs家族成员间mRNA变化存在差异:与sham组相比SNI大鼠FGFR1 mRNA表达术后第1天高。SNI组和sham组大鼠FGFR2~4 mRNA在术后5天之内维持在低水平,而SNI组大鼠在第7天显著升高,两组之间差异显著。结论:NP中脊髓星形胶质细胞GFAP的改变以及不同FGFRs mRNA的变化可能对于NP的发生与维持有重要意义。     

植物雌激素对去卵巢血管性痴呆大鼠认知功能和海马胆碱乙酰转移酶表达的影响

目的:观察植物雌激素对去卵巢血管性痴呆(VD)大鼠海马胆碱能神经元表达的影响,探讨植物雌激素对去卵巢VD大鼠的脑保护作用及可能机制。方法:60只雌性Wistar大鼠经水迷宫筛选随机分为4组。Ⅰ组(sham组):VD大鼠,未去除卵巢;Ⅱ组(OVX组):VD大鼠,去除卵巢;Ⅲ组(OVX+est组):VD大鼠,去除卵巢,给予化学雌激素喂养;Ⅳ组(OVX+phy组):去除卵巢,给予植物雌激素喂养。4组大鼠VD手术前后分别应用Morris水迷宫检测法进行大鼠空间认知功能的评价。采用胆碱乙酰转移酶(ChAT)免疫组织化学ABC法,观察去卵巢VD大鼠各组海马胆碱能神经元的数目。结果:与OVX组相比,OVX+est组及OVX+phy组的大鼠海马胆碱能神经元数目明显升高(P<0.05),且在水迷宫中找到水下平台的时间、距离明显缩短(P<0.05),而与sham对照组差别不明显,且OVX+est组和OVX+phy组相比较,无显著性差异(P>0.05)。结论:植物雌激素具有雌激素样作用,能增强大鼠海马胆碱能神经元的ChAT表达,对血管性痴呆大鼠的记忆损害有一定程度的保护作用。     

聚焦式低强度脉冲超声治疗对大鼠坐骨神经损伤后神经病理性疼痛的影响

目的:观察聚焦式低强度脉冲超声(focused low-intensity pulsed ultrasound,FLIPUS)对坐骨神经损伤模型(spared nerve injury,SNI)大鼠的镇痛作用,以及对脊髓神经重塑的影响.方法:建立SNI神经病理性疼痛大鼠模型.将30只雄性SD大鼠随机分成3组,假手术组、...     

神经病理性疼痛引起大鼠空间记忆障碍和内侧前额叶PSD95以及CaMK Ⅱ-Thr~(305)的表达升高

目的:研究神经病理性疼痛(neuropathic pain,NP)对大鼠空间学习记忆功能和内侧前额叶(medical prefrontal cortex,m PFC)钙/钙调素依赖性蛋白激酶Ⅱ(alpha calcium/calmodulindependent protein kinaseⅡ,Ca MKⅡ)磷酸化水平以及突触后密度蛋白95(postsynaptic density protein 95,PSD95)表达的影响。方法:选择经过八臂迷宫训练的雄性健康Wistar大鼠32只,将大鼠随机分为4组,神经病理性疼痛模型组(NP group,NP组,n=8),NP模型m PFC注射生理盐水组(NS组,n=8),NP模型m PFC注射Ca MKⅡ抑制剂KN-93组(KN-93组,n=8)和假手术组(sham operated group,SO组,n=8)。采用坐骨神经慢性压迫损伤制备大鼠NP模型。各组大鼠分别于术后第7、14、21、28和35天测机械缩足阈(mechanical withdrawal threshold,MWT)和热缩足潜伏期(thermal withdrawal latency,TWL),第29~35天再次进行八臂迷宫实验以检测大鼠的空间学习和记忆功能。术后第33天采用立体脑穿刺进行药物干预试验,建立NP模型m PFC注射生理盐水组(NS组)和NP模型m PFC注射Ca MKⅡ抑制剂KN-93组(KN-93组)两组实验模型,第35天进行八臂迷宫检测大鼠的空间学习和记忆功能,检测后立即处死大鼠,通过Western Blotting、RT-PCR和免疫荧光方法测定m PFC部位Ca MKⅡ磷酸化位点Thr305磷酸化水平和突触小体内PSD95表达水平。结果:与SO组相比,NP组、NS组和KN-93组的术后痛阈明显降低(P<0.05)。与SO组相比,NP组空间学习和记忆功能减退,PSD95表达升高,Ca MKⅡ-Thr305水平升高(P<0.05)。与NS组比较,KN-93组空间学习和记忆功能改善,PSD95表达降低,Ca MKⅡ-Thr305水平降低(P<0.05)。结论:NP能引起大鼠空间学习和记忆能力减退并使m PFC脑区的PSD95表达水平和Ca MKⅡ磷酸化水平升高。     

背根神经节血红素加氧酶1过表达缓解小鼠神经病理性疼痛

目的:探讨背根神经节(dorsal root ganglion,DRG)中血红素加氧酶1(heme oxygenase 1,HO-1)的表达分布及在DRG中过表达HO-1对神经病理性疼痛的作用。方法:构建保留性坐骨神经损伤(spared nerve injury,SNI)诱导的神经病理性疼痛模型;行为学检测机械性触诱发痛;免疫荧光染色检测DRG中HO-1在神经元中表达和分布;免疫印迹检测DRG中HO-1表达。结果:免疫荧光染色显示DRG中HO-1阳性神经元在SNI后数量显著减少;DRG中HO-1阳性神经元主要是IB4阳性的小型神经元(<300μm2);连续5天腹腔注射原卟啉IX氯化钴(cobalt protoporphyrin-IX,CoPP)能增加神经病理性疼痛小鼠的机械缩足阈值;鞘内注射过表达HO-1的腺病毒相关病毒(adenovirus associated virus,AAV)能特异性浸染DRG神经元,并上调HO-1表达;同时能有效提高神经病理性疼痛小鼠的机械缩足阈值,此效应持续21天以上。结论:DRG中HO-1主要表达在IB4阳性的小型神经元;过表达DRG神经元中HO-1能有效缓解SNI诱导的神经病理性疼痛。     

长时间次声作用对大鼠学习记忆功能的影响

目的:通过观察长时间次声作用对大鼠学习记忆功能及隔内侧核(MS)和斜角带核(DB)超微结构的影响,探讨次声对大鼠学习记忆功能影响的机制。方法:16Hz,130dB次声作用SD大鼠2h/d,共42d,避暗回避实验观察大鼠学习记忆功能的改变,透射电镜观察大脑MS和DB超微结构的改变。结果:与对照组相比,实验组大鼠避暗回避实验错误次数明显增多,(2.9±1.9)次,对照组(0.8±0.8)次,潜伏期明显缩短,(153±22)s,对照组(290±15)s(t=3.61,P<0.01)。受损神经元的线粒体损伤,核糖体、糖原减少,溶酶体、脂褐素增多。结论:长时间次声作用可使隔-海马胆碱能通路神经元超微结构改变,并与大鼠学习记忆功能下降有关。     

伏隔核参与神经病理性疼痛慢性化的机制研究

<正>最近人体试验发现,伏隔核(NAc)在神经病理性疼痛慢性化中发挥重要作用,但是具体机制不清楚。本研究采用慢性痛动物模型,探索NAc参与神经病理性疼痛慢性化的机制。方法:(1)动物模型:大鼠坐骨神经分支部分损伤(SNI)模型;(2)检测时间点:SNI术前2 d、术后5 d和术后28 d;(3)评价指标:触诱发痛、静息状态功能磁共振成像(rs-f MRI)功能连接、NAc受体基因表达(DR1a、DR2、KOR、CB1、     

曲马多复合右美托咪定对神经病理性疼痛大鼠的镇痛效果研究

目的研究曲马多复合右美托咪定对神经病理性疼痛所致大鼠认知功能障碍和内侧前额叶脑区NR2B表达的影响。方法 50只健康的雄性Wistar大鼠随机分为5组(每组10只),分别为假手术组(SO组),神经病理性疼痛模型组(NP组),模型注射曲马多组(T组),模型注射右美托咪定组(D组),模型注射曲马多+右美托咪定组(T+D组)。神经病理性疼痛模型采用左侧坐骨神经主干慢性压迫法制备。T组、D组和T+D组于术后3天开始分别每天尾静脉注射曲马多注射液(20 mg/kg)、右美托咪定(25μg/kg)、曲马多注射液(5 mg/kg)+右美托咪定(5μg/kg),SO组和NP组以等量生理盐水代替。各组大鼠分别于术后第3天、7天、10天和14天测右侧后足机械缩足阈(MWT)和热缩足潜伏期(TWL)。术后第14天,通过八臂迷宫实验检测大鼠的认知功能变化。八臂迷宫实验完成后立即处死大鼠,通过Western Blot方法检测内侧前额叶脑区NR2B表达水平。结果与SO组比较,NP组的术后痛阈明显降低(P0.05),认知记忆能力明显降低(P0.05),NR2B表达明显升高(P0.05)。与T组和D组比较,T+D组的术后痛阈升高(P0.05),认知记忆能力明显升高(P0.05),NR2B表达明显下降(P0.05)。结论曲马多复合右美托咪定的镇痛效果比单独应用曲马多或右美托咪定效果好,可改善大鼠NP导致的认知功能障碍并使内侧前额叶脑区NR2B表达降低。     

STAGGERS IN SHEEP IN PATAGONIA

After observations and experimental work both in the field and laboratory, the following conclusions seem justified. 1. Staggers is a non-infectious disorder affecting horses, cattle, and sheep. 2. The disease is characterized by weakness, muscular twitching, irregular movements of the head, stiffness of the limbs, and transient motor paralysis, accompanied with spastic spasms on excitement. There is also a derangement of vision and conjunctivitis. 3. The postmortem lesions are not characteristic. 4. We readily produced the disease by feeding susceptible sheep on a coarse tuft grass commonly known as coiron or pampa grass (Poa argentina). 5. The time required to produce definite symptoms by feeding the grass varied. Two animals developed typical staggers after two feedings; in another instance a period of 21 days of feeding was required. The average time for the production of unmistakable symptoms in our experiments was 10 days. 6. Many sheep recover from staggers spontaneously. A complete change of diet will usually effect a cure within 2 weeks. 7. Older .animals that have pastured for long periods on lands where the grass grows become tolerant and are rarely affected with staggers. 8. The grass is toxic to sheep at all seasons of the year. We fed late winter and early spring grass and grass in flower, and produced staggers in every instance. The young green grass is as toxic as any edible portion of the plant.     

TIMBER IN AUSTRALIA IN WARTIME

Fire history since 1850 was reconstructed by analysing tall wet eucalypt forest stands in the Warra long-term ecological research (LTER) site in southern Tasmania. Major fires occurred in 1898, 1906, 1914 and 1934. Fifty-seven percent of the forest has remained unburnt since 1850. Sixty percent of the forest burnt since 1850 occurs as mixed age stands, while 40 percent is pure regrowth. Ring counts of stumps of three veteran eucalypt trees indicated that the mature and oldgrowth forests of the Warra site represent a number of pre-1850 fires. One extant oldgrowth eucalypt stand was estimated to be over 450 years old. The common occurrence of multi-aged wet eucalypt stands has silvicultural implications where a management objective is to emulate pre-existing stand structures. While the fire history reported here is limited mainly to the period since 1850, it provides a good basis for understanding the current stand structures of the tall wet eucalypt forests of the Warra site. Such an understanding is essential to interpret results from current and planned ecological studies associated with the LTER program at Warra.     

BACTERIUM PNEUMOSINTES IN CLINICAL INFLUENZA IN NEW YORK CITY IN 1926

The presence of Bacterium pneumosintes has been demonstrated in nasopharyngeal washings from 2 patients in a sporadic outbreak of clinical influenza in New York City in March, 1926. 2 strains of bacteria morphologically similar to Bact. pneumosintes, but differing in certain cultural characters, and 2 other anaerobic filter-passing organisms were also isolated from the 9 patients examined. The blood serum of 16 among 17 persons convalescent from clinical influenza, and of 6 among 10 supposedly normal persons, agglutinated 1 or more strains of Bact. pneumosintes.