慢性间歇性低压低氧对老年大鼠自发运动行为及黑质多巴胺能神经元的影响

目的:用慢性间歇性低压低氧(CIHH)模型,探讨CIHH对老年大鼠自发运动行为以及黑质多巴胺能神经元的影响。方法:用CIHH模型处理老年大鼠30 d,通过旷场实验检测大鼠自发运动行为的改变,通过实时定量PCR和免疫印迹检测黑质多巴胺能神经元酪氨酸羟化酶(TH)和多巴胺转运体(DAT)表达的变化。结果:老年组大鼠旷场实验中闻嗅行为、探索行为、运动行为和理毛行为与成年组相比均显著下降,CIHH处理后理毛行为没有改变,闻嗅行为、探索行为和运动行为显著改善,但没有达到成年组水平;老年组大鼠黑质多巴胺能神经元TH和DAT的表达与成年组相比均显著下降,老年CIHH组TH和DAT的表达升高,但没有达到成年组水平。结论:CIHH可改善老年大鼠闻嗅行为、探索行为和运动行为,并提高黑质多巴胺能神经元TH和DAT的表达。     

Genistein对Parkinson病模型小鼠黑质纹状体通路的保护作用

为了研究大豆异黄酮活性成分genistein对1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)制备的去卵巢(OVX)Parkinson病(PD)模型小鼠黑质纹状体通路的保护作用,我们将OVX PD小鼠随机分为对照组、MPTP组、genistein预处理组和雌激素预处理组,采用免疫组织化学染色结合逆转录-聚合酶链式反应法(RT-PCR)检测黑质致密带(SNpc)神经元酪氨酸羟化酶(TH)的表达情况,采用高效液相色谱法(HPLC-ECD)检测小鼠纹状体(Str)多巴胺(DA)及其代谢物二羟基苯乙酸(DOPAC)和高香草酸(HVA)的含量。结果显示:Genistein及雌激素用药组SN内TH阳性神经元数量及THmRNA的表达水平较MPTP组显著升高(P<0.01)。MPTP组Str内DA及其代谢产物DOPAC和HVA的含量较对照组明显降低(P<0.01)。genistein及雌激素用药组Str内DA、DOPAC及HVA含量较MPTP组显著升高(P<0.01)。上述结果提示genistein对MPTP制备的PD模型小鼠黑质DA能神经元有明显的保护作用。     

外源性EGF对中年大鼠运动活性及纹状体多巴胺含量的影响

目的:探讨表皮生长因子(EGF)对中年大鼠运动活性以及纹状体多巴胺含量的影响。方法:经皮给予健康18月龄大鼠不同剂量EGF(0.01,0.05,0.1,0.15,0.3 mg/ml),通过旷场实验检测大鼠运动行为的改变,通过液相色谱-串联质谱分析多巴胺的含量变化。结果:与对照组相比,小剂量EGF组大鼠(0.01,0.05 mg/ml)旷场实验中各行为参数没有变化;中等剂量EGF组大鼠(0.1,0.15 mg/ml)旷场实验中闻嗅行为、探索行为、趋触性行为、运动行为和理毛行为改善;大剂量EGF(0.3 mg/m1)组大鼠旷场实验中各行为参数下降。纹状体多巴胺及其代谢产物DOPAC和HVA的含量与对照组相比,小剂量EGF(0.01 mg/rnl)组开始上升,中等剂量EGF(0.1 mg/ml)组达到峰值,大剂量EGF(0.3 mg/ml)组下降。结论:EGF对中年大鼠运动活性以及纹状体多巴胺的含量均有影响。     

氯化锰对大鼠中脑多巴胺能神经元毒性的研究

本文通过锰诱导多巴胺能神经元凋亡及其可能的神经化学机制的研究 ,进而探讨锰中毒与帕金森病发病的相互关系。分离培养大鼠中脑黑质多巴胺能神经元用不同剂量 Mn Cl2 处理后 ,用荧光染料进行染色 ,观察了凋亡神经元数量。用腹腔注射及脑内单侧注射 Mn Cl2 染毒方法处理大鼠 ,并采用脑内微透析技术和高效液相色谱 -电化学方法 (HPLC-ECD)在活体检测了术后不同时间的纹状体细胞外液中 DA及其代谢产物 DOPAC、HVA以及 5 -HT的代谢产物 5 -HIAA等的含量 ;同时作丙二醛含量和过氧化物歧化酶活性检测。结果发现 ,凋亡神经元的细胞核缩小、不规则、染色质呈块状深染 ,凋亡细胞数量随 Mn Cl2 剂量升高而增多。Mn Cl2 脑内注射侧与注射对侧相比 ,术后 4、7、10、2 0 d的 DA、DOPAC、HVA和 5 -HIAA含量均有不同程度的降低。腹腔染毒高、低剂量组 2 0 d后大鼠整体纹状体匀浆的上述指标也明显降低。此外 ,染毒大鼠纹状体中丙二醛水平随染毒剂量增高而增高 ,过氧化物歧化酶活性随染毒剂量增高却下降。以上结果表明 ,锰中毒可能是引起帕金森病发病的原因之一     

骨髓基质细胞对离体Parkinson鼠脑片单胺类神经递质的影响

为探讨骨髓基质细胞对离体Parkinson鼠脑片单胺类神经递质的影响,本研究通过建立新生大鼠离体“Parkinson鼠病”模型,取成年大鼠骨髓,培养、分离、纯化骨髓基质细胞,将骨髓基质细胞(MSCs)与离体脑片联合培养,应用高效液相法观察了脑片和培养液中多巴胺及其代谢产物3,4-二羟苯乙酸(DOPAC)和高香草酸(HVA)含量的变化。结果显示,经MPTP代谢产物mpp+损伤的脑片多巴胺含量与正常组、联合培养组相比明显减少(P<0.01),而mpp+组培养液内DOPAC和HVA含量也减少(P<0.05)。但联合培养组与正常组相比DA,DOPAC和HVA的变化无显著差异。以上结果提示,联合培养的骨髓基质细胞对mpp+毒性损伤的多巴胺能神经元具有保护作用,该模型也为在脑片上测量单胺类神经递质提供了可靠的方法。     

甲基苯丙胺对相关脑区的神经毒性作用

目的:研究甲基苯丙胺(MA)对大鼠纹状体、海马、额叶皮质等脑区神经细胞的毒性作用以及对大鼠行为的影响。方法:H-E染色、Glees银浸染观察神经元和轴突的变化;高效液相色谱检测上述脑区多巴胺(DA)及其代谢产物含量;免疫组化胶质纤维酸性蛋白(GFAP)检测胶质细胞增生情况。结果:MA对上述脑区神经细胞和轴突有损伤作用,表现为神经细胞变圆,极性消失;胶质细胞增生,噬神经细胞现象、胶质小结形成;神经轴索扭曲,节段性增粗,轴索间隙增宽;GFAP阳性星形细胞增多;纹状体DA及其代谢产物含量显著降低,海马、额叶皮质DA含量明显降低;大鼠行为改变明显。结论:MA对大鼠中枢神经系统多脑区神经元有明显的毒性作用,可导致上述脑区DA含量下降和大鼠行为改变。     

黑质损毁的大鼠双侧尾壳核多巴胺及其代谢产物的高效液相色谱-电化学测定

正常及用6-羟基多巴胺(6-OHDA)损毁黑质的28只大白鼠分成3组,用高效液相色谱-电化学检测器(high performance liquid chromatography-electrochemical detection,HPLC-EC)分别测定其两侧尾壳核中多巴胺(DA)及其代谢产物高香草酸(HVA)、3,4-二羟基苯乙酸(DOPAC)的含量。单侧损毁组损毁侧尾壳核中DA、HVA/DA、DOPAC/DA 3项指标,分别相当于健侧的22.27％、420.00％、199.75％,显示损毁侧纹状体内幸存的DA神经末梢有代偿性的递质释放增强效应。单侧损毁组损毁侧与双侧损毁组两侧尾壳核间、单侧损毁组健侧与正常对照组两侧尾壳核间,上述各指标差异无显著性,提示损毁侧尾壳核内代偿性的多巴胺释放增强效应,很可能是同侧黑质-纹状体系统的机能代偿所致。     

过表达Nurr1基因的骨髓间充质干细胞的诱导及移植治疗帕金森病的研究

目的:探讨Nurr1基因修饰大鼠骨髓间充质干细胞(mesenchymalstemcells,rMSCs)脑内移植对帕金森病(parkinsondiseasePD)大鼠的治疗作用。方法:用脂质体转染法转染PcDNA3.1(+)-Nurr1入rMSCs并稳定表达.然后移植大鼠PD模型纹状体内;观察行为学变化并用免疫组化、RT-PCR等方法检测移植细胞的Nurr1、DAT和TH表达;利用高效液相色谱检测多巴胺(DA)、二羟苯乙酸(DOPAC)和高香草酸(HVA)含量。结果:Nurr1-rMSCs组和rMSCs组移植治疗8周内PD大鼠旋转行为均得到一定的改善(P<0.05);移植后2～4周Nurr1-rMSCs组较rMSCs组改善程度更为显著(P<0.05),但第8周时二组行为学差异无统计学意义(P>0.05)。免疫组化显示Nurr1-rMSCs能够稳定表达Nurr1且少量细胞表达DAT,但未发现TH阳性细胞。而rMSCs组和对照组则均未发现有Nurr1、DAT、TH表达;RT-PCR检测显示移植后2～8周,Nurr1-rMSCs组移植区有Nurr1和DATmRNA表达,但未发现THmRNA表达;两治疗组DA、DOPAC和HVA含量均较对照组增高(P<0.05)。结论:Nurr1基因转染大鼠骨髓间充质干细胞移植大鼠纹状体可以在一定时期内存活并有效表达,同时可提高纹状体DA含量,改善模型鼠症状,为治疗PD的研究提供了实验依据。     

银杏叶提取物对帕金森病模型小鼠多巴胺能神经元保护作用研究

目的研究银杏叶提取物（GBE）对帕金森病模型小鼠黑质（SN）多巴胺（DA）能神经元的保护作用。方法36只C5,Bk小鼠随机3组,每组12只。其中,帕金森病（PD）模型组的小鼠采用1-甲基-4-苯基-1,2,3,6-四氢吡啶（MPTP）腹腔注射（30mg／kg×5d）诱导PD;GBE预处理组的小鼠于注射MPTP前2h腹腔注射GBE（60mg／kg×8d）;正常对照组的小鼠只注射等体积生理氯化钠溶液。应用免疫组织化学染色观察小鼠黑质致密带（SNzc）酪氨酸羟化酶（TH）免疫反应阳性细胞数量的变化,用高效液相色谱法（HPLC-ECD）检测小鼠纹状体（Str）内DA及其代谢物二羟基苯乙酸（DOPAC）和高香草酸（HVA）含量。结果PD模型组小鼠SN内酪氨酸羟化酶（TH）阳性细胞数量、Str内DA及其代谢产物DOPAC和HVA的含量明显减少（P〈0．01）,GBE预处理组小鼠SN内TH阳性细胞数量、Str内DA及其代谢产物DOPAC和HVA的含量明显增多（P〈0.05）,但仍低于正常对照组（P〈0．01）。结论GBE对MPTP致帕金森病小鼠SNDA能神经元具有明显的保护作用。     

电针预处理百会穴对大鼠中枢疲劳影响的初步研究

目的:通过电针(electroacupuncture,EA)预处理百会穴,观察大鼠中枢疲劳(central nervous system fa-tigue,CNS fatigue)后各项指标的改变,研究电针预处理对中枢疲劳的影响。方法:成年SD大鼠分6组:空白对照组(control)、电针组(EA)、1 d疲劳对照组(1 d fatigue)、2 d疲劳对照组(2 d fatigue)、1 d疲劳电针组(EA+1 dfatigue)、2 d疲劳电针组(EA+2 d fatigue)。通过负重游泳时间和旷场试验判断大鼠疲劳程度,采用高效液相色谱(High Performance Liquid Chromatography,HPLC)电化学检测法检测大鼠海马、纹状体、下丘脑和中脑内5-羟色胺(5-hydroxytryptamine,5-HT)、多巴胺(dopamine,DA)和其代谢产物的比值,研究电针预处理对疲劳的影响。结果:建模1 d后疲劳电针组的负重游泳时间比疲劳对照组显著提高(P<0.01),旷场实验结果表明疲劳电针组的自发活动明显多于疲劳对照组。HPLC结果显示建模1 d后疲劳电针组大鼠的纹状体、中脑内5-羟吲哚乙酸(5-hydroxy-indole-acetic acid,5-HIAA)/5-HT比值和下丘脑、中脑内[3,4-二羟基苯乙酸(3,4-dihydroxyphenyl-aceticacid,DOPAC)]+高香草酸(homovanillic acid,HVA))/DA比值低于疲劳对照组(P<0.05),建模2 d后四个脑区的5-HIAA/5-HT比值和海马、下丘脑内的(DOPAC+HVA)/DA比值与对照组相比均明显降低(P<0.05)。结论:电针预刺激百会穴可以改善中枢疲劳后大鼠的体力和自主活动能力,并能够减轻中枢疲劳程度。     

Dopamine release in the nucleus accumbens of freely moving rats determined by on-line dialysis: effects of apomorphine and the neuroleptic-like peptide desenkephalin-gamma-endorphin

This study examined the effects of apomorphine, sulpiride, desenkephalin-gamma-endorphin (DE gamma E) and a combination of DE gamma E with apomorphine on the release of dopamine (DA) and its main metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the nucleus accumbens of freely moving rats. A fully automated on-line brain dialysis system was used. A small dose of s.c. administered apomorphine induced a decrease in the output of DA and DOPAC. Sulpiride, infused into the nucleus accumbens, induced a 2-fold increase in the output of DA, DOPAC and HVA. DE gamma E hardly modified either the basal release of DA, DOPAC and HVA or the apomorphine-induced attenuation of the release of DA and DOPAC. These results indicate a dissociation between the behavioural effects of DE gamma E and its effect on the release of DA in vivo.     

Changes in monoamines and their metabolite levels in some brain regions of aged rats

The concentrations of dopamine (DA) norepinephrine (NE), serotonin (5HT) and their metabolites, HVA, DOPAC, MHPG-SO4 and 5HIAA were measured in several brain areas of rats aged 4, 18 and 29 months. Dopamine and its metabolites showed a decline, statistically correlated with age, in all the dopaminergic areas considered, indicating that this system is profoundly affected in the senescent rat. The changes in the noradrenergic system were more complex. This neurotransmitter was reduced in spinal cord and in limbic area, but was not modified in hippocampus, cerebellum, striatum and s. nigra. In cortex, MHPG-SO4, the main NE metabolite, showed a significantly age-related increase. Tyrosine hydroxylase (TH) activity was low in striatum, and brainstem but not in hypothalamus of aged rats. Neither 5HT nor its metabolites was affected by age. The results indicate that central catecholaminergic systems are markedly affected in senescent rats.     

In vivo release of dopamine and its metabolites following a direct infusion of L-dopa into the caudate nucleus of awake, freely behaving rats using a push-pull cannula

In vivo release of dopamine (DA) and its metabolites were determined following a direct infusion of 3,4-dihydroxyphenylalanine (L-DOPA) through a push-pull cannula in the caudate nucleus of unanesthetized, freely behaving rats. L-DOPA infusions increased the release of DA and dihydroxyphenylacetic acid (DOPAC) beginning with 10(-5) M L-DOPA, while homovanillic acid (HVA) was released consistently only following 10(-3) M L-DOPA. Maximal release of DA preceded that of DOPAC which preceded that of HVA. No salient changes in 5-hydroxyindoleacetic acid or behavior were observed following any L-DOPA dose.     

The long-term effects of neurotoxic doses of methamphetamine on the extracellular concentration of dopamine measured with microdialysis in striatum.

The extracellular concentrations of dopamine (DA), dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5-HIAA) in the striatum were measured by in vivo microdialysis in freely moving rats one week after the animals were treated with neurotoxic doses of methamphetamine. Methamphetamine produced a marked depletion of striatal DA measured in postmortem tissue, and in the extracellular concentrations of DOPAC, HVA and 5-HIAA. In contrast, the resting extracellular concentration of DA in striatum was the same as in saline-pretreated controls. Furthermore, methamphetamine-pretreated rats were able to increase their concentration of extracellular DA to the same extent as controls in response to a (+)-amphetamine challenge. It is suggested that this adaptive response is probably responsible, at least in part, for the absence of obvious behavioral deficits in animals exposed to neurotoxic doses of methamphetamine.     

Aged Fischer 344 rats exhibit altered orolingual motor function: relationships with nigrostriatal neurochemical measures

The present study utilized a novel behavioral preparation to measure differences in orolingual motor function between young (6 months) and aged (24 months) Fischer 344 (F344) rats. Rats were trained to lick an isometric force-sensing operandum for water reinforcement so that the number of licks per session, licking rhythm and lick force could be compared between the two groups. The aged rats exhibited a greater number of licks per session, but a slowed licking rhythm, compared to the young rats. Lick force did not differ significantly between the groups. The dopamine (DA) uptake inhibitor nomifensine decreased all three measures in both groups. Analyses of whole brain tissue content of DA, 3,4 dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA) in the substantia nigra and dorsal striatum revealed no significant differences between the two age groups. Differences were observed between the two groups with respect to relationships between behavioral and neurochemical tissue measures. Striatal DA content and the number of licks per session were positively correlated for the young rats but not for the aged rats. In the aged rats, but not the young rats, positive correlations were also observed between licking rhythm and the DOPAC+HVA/DA ratio in the substantia nigra. These findings suggest that age-related alterations in orolingual motor function may relate in part to functional changes in DA neuronal circuits.     

Preservation of dopamine release in the denervated striatum

Dopamine metabolism and release were determined in the striata of rats sustaining varying damage to the nigrostriatal dopamine (DA) projection. DA metabolism, inferred from concentrations of dihydroxy-phenylacetic acid (DOPAC) or homovanillic acid (HVA), decreased with DA denervation of more than 20%. Dopamine release, inferred from the concentration of 3-methoxytyramine (3-MT), did not decrease unless the denervation was at least 80%. The amount of 3-MT per surviving neuron exceeded that for DOPAC over most of the denervation range. Thus, striatal DA release is preserved at normal levels with the survival of only 20% of the striatal DA innervation. Decreases in DA release, rather than decreases in DA metabolism or the density of dopamine innervation, coincide with the appearance of behavioral impairments.     

Morphine-stimulated metabolism of striatal and limbic dopamine is dissimilarly sensitized in rats upon withdrawal from chronic morphine treatment

The effects of acute morphine on the release of dopamine (DA) in the striatum and limbic forebrain of rats upon 48 h withdrawal from 20-day morphine treatment were studied using 3-methoxytyramine (3-MT) in tissue as an index of DA release. Homovanillic acid (HVA) and 3,4-dihydroxyphenylacetic acid (DOPAC) were also measured. The chronic morphine treatment did not alter the concentrations of DA metabolites. Acute morphine (10 mg/kg) elevated all three DA metabolites in both brain areas. Morphine withdrawal potentiated the elevation of striatal and limbic 3-MT as well as that of striatal but not limbic HVA. These findings show that both striatal and limbic DA mechanisms are sensitized to morphine upon withdrawal but that sensitization of DA metabolism in these two brain areas occurs differently.     

龟板对帕金森病大鼠行为和脑内多巴胺水平的影响

目的　探讨益肾中药龟板对帕金森病大鼠的治疗作用。方法　 6 羟基多巴胺脑内定位注射制备帕金森病模型 ,随机将 4 0只SD大鼠分为实验组和对照组 ,观察动物单侧旋转行为以及多巴胺及其代谢产物 3、4 二羟苯乙酸和高草酸含量的变化。结果　造模 8周后实验组帕金森病大鼠旋转圈数 6 97± 1 6 7比对照组 9 4 5± 1 75明显减少 (P <0 0 5 ) ;其纹状体内多巴胺 (DA)及其代谢产物 3、4二羟苯乙酸 (DOPAC)、高香草酸 (HVA)含量显著提高 ,分别为 3 12± 0 4 8,0 2 7± 0 0 6和 0 35±0 0 6 ,而对照组仅为 0 4 9± 0 0 4 ,0 0 7± 0 0 3和 0 2 7± 0 0 3(P <0 0 5 )。结论　益肾中药龟板对大鼠帕金森病具有潜在的临床应用价值。     

Alcohol-preferring rats: genetic sensitivity to alcohol-induced stimulation of dopamine metabolism

The effect of ethanol on brain dopamine (DA) metabolism in the caudate nucleus (CN), olfactory tubercle (OT) and medial prefrontal cortex (MPFC) was compared in two selectively bred rat lines, one ethanol preferring and the other ethanol nonpreferring. Male rats from the 16th and 17th generations of both lines that never experienced ethanol beforehand were used. No differences in the basal concentrations of DA and its metabolites, DOPAC and HVA, in the above brain regions were found between the two lines. The oral administration of 2 g/kg of ethanol to ethanolnonpreferring rats increased DOPAC and HVA and reduced DA levels in the CN and OT but was ineffective in the MPFC. On the other hand, ethanol administration to ethanol-preferring rats decreased DA content and increased DOPAC and HVA levels, not only in the CN and OT, but also in the MPFC. Moreover, the changes induced by ethanol on DA metabolism in the latter group were significantly greater than in ethanol nonpreferring rats. These results indicate that ethanol preferring rats have a genetic high sensitivity to the ethanol effect on DA metabolism, and suggest that such a trait might play a role in ethanol preference.