急性应激时大鼠脑内一氧化氮及一氧化氮合酶的变化

目的：探讨急性应激状态下脑内一氧化氮（NO）含量和一氧化氮合酶（NOS）活性的变化及意义。方法：采用放免法测定强迫游泳应激后1、3小时的大鼠额叶、海马、中脑和下丘脑内NO含量和NOS活性。结果：应激结束后1小时，海马和下丘脑内NO含量和NOS活性均显著增高（t分别为2．32、2．61，P均＜0．05）。应激结束后3小时，额叶、海马、中脑和下丘脑内NO含量均显著增高（t分别为3．57、4．26、3．88、4．93，P均＜0．01），NOS活性均显著性增高（t分别为2．32、2．61，P均＜0．05）。结论：急性应激状态下，各脑区的NOS活性增加，产生的NO可能介导了神经毒性作用。     

急性应激时大鼠脑内环核苷酸含量的变化

目的：探讨在急性应激状态下脑内的环核苷酸的变化及意义。方法：采用放免法测定游泳应激后1、3小时的大鼠额叶、海马、中脑和下丘脑内环磷腺腺苷（cAMP)、环磷酸鸟苷（cGMP)含量。结果：应激结束后1小时，海马和下丘脑内cGMP水平均显著性增高。（t分别为2．33、2．48，P均＜0．05）。应激结束后3小时，额叶、海马、中脑和下丘脑内cAMP均显著性增高（t分别为2．49、3．03、2．75、3．34，P均＜0．05），cGMP水平均显著性增高（t分别为3．34、3．67、P均＜0．01）。结论：急性应激状态下，脑内的环核苷酸被激活，cGMP可能首先被激活。     

急性应激大鼠脑边缘系统生化病理变化

目的 :探讨急性应激时NO等自由基对脑损害作用及超微结构的影响。方法 :建立急性应激大鼠模型 ,分别取边缘系统额叶、海马、下丘脑组织 ,电镜观察神经细胞超微结构变化、测定组织匀浆NO含量和SOD活力。结果 :急性应激组大鼠额叶、海马及下丘脑SOD活力均高于对照组 (P <0 0 5 ) ,NO含量在海马、下丘脑升高明显 (P <0 0 5 ) ,光镜和电镜下的海马、下丘脑神经细元减少 ,核仁碎裂、胞质内细胞器减少。结论 :急性应激脑组织NO含量和SOD活力增高 ,可对边缘系统下丘脑、海马造成损害。这可能是应激反应过度的病理生理学基础     

急性高原应激大鼠脑组织NO、SOD及血浆皮质醇的含量变化

目的 :观察急性高原应激大鼠脑组织一氧化氮 (NO)含量和超氧化物歧化酶 (SOD)活力变化 ,探讨高原应激自由基对脑的损害作用。方法 :通过急性进入高原建立急性应激模型 ,分别取脑边缘系统大脑额叶、海马、下丘脑及中脑 ,制成脑组织匀浆 ,测定NO含量和SOD活力 ,测定血浆皮质醇含量。结果 :急性高原应激组大鼠大脑额叶、海马、下丘脑组织SOD活力明显高于对照组 (P <0 0 5 ) ,NO含量在海马、下丘脑升高明显 (P <0 0 5 ) ,血液皮质醇含量增高。结论 :在高原应激反应对脑的损害中 ,自由基细胞毒性作用可能是重要因素     

睡眠剥夺对大鼠一氧化氮和一氧化氮合酶的影响

目的：探讨睡眠剥夺对大鼠脑组织一氧化氮（NO）及一氧化氮合酶（NOS）影响。方法：采用小平台水环境法（Flower Pot)制作大鼠睡眠剥夺模型，采用化学法和酶法观察不同时间睡眠剥夺后大鼠额叶、海马、中脑和下丘脑NO含量及NOS活性变化。结果：与正常对照组及大平台组比较，大鼠在SD后额叶和海马的NO含量及NOS活性增高，有显著性差异（P＜0．01－0．05），其余脑区无显著性差异（P＞0．05）。随着剥夺时间的延长，额叶和海马NO含量及NOS活性增高更加明显。结论：睡眠剥夺可致NO及NOS升高，可能与其学习障碍有关，NO可能参与大鼠的睡眠调节。     

强迫游泳对小鼠脑内一氧化氮及一氧化氮合酶的影响研究

目的 :探讨应激对小鼠脑内一氧化氮 (NO)及一氧化氮合酶 (NOS)的影响及意义。方法 :将 6 0只雄性昆明品系小鼠随机分为 3组。其中对照组 2 0只 ,强迫游泳分 2组各 2 0只。分别于强迫游泳 (实验组 )后 1h (一组 )、 2h (二组 )取脑组织检测NO含量及NOS活性。结果 :对照组NO及NOS分别为 2 7 4 7± 15 16 μmol/gprot、 2 16± 0 5 3U/mgprot。实验一组为 17 83± 5 6 3μmpl/gprot、 2 76± 0 87U/mgprot ;实验二组为 11 38± 1 2 2 μmpl/gprot、 3 2 9± 0 4 1U/mgprot。急性应激后 1hNO水平降低并有统计学意义 (t =2 6 7,P <0 0 5 ) ;2h后进一步降低 (t=5 0 5 ,P <0 0 1)。急性应激后 1hNOS活性增高并有统计学意义 (t =-2 4 2 ,P<0 0 5 )。应激后NO与NOS变化呈显著性负相关 (r=-0 316 ,P <0 0 5 )。结论 :神经递质NO及NOS参与了中枢神经急性应激反应 ,且NO水平降低、NOS活性增高。     

不同应激方式对大鼠血清一氧化氮合酶活性影响的差异性

目的 :研究不同应激方式对大鼠血清一氧化氮合酶 (NOS)活性影响的差异。方法 :采用强迫游泳和心理社会应激建立应激动物模型 ,于应激后 2小时测定两组血清NOS活性。结果 :强迫游泳应激后 ,NOS活性高于正常大鼠 (P <0 0 1) ;心理社会应激后 ,NOS活性显著降低 (P <0 0 5 )。结论 :不同的应激方式对NOS活性影响不一致 ,强迫游泳可能具有更多躯体方面的效应。     

强迫游泳大鼠脑内信号分子ERK1/2磷酸化水平的变化

通过观察强迫游泳时大鼠脑内不同核团内ERK1/2磷酸化水平变化,探讨与负性心理应激有关的脑内环路。将大鼠置于高60cm、水深约30cm的玻璃缸内,先预游15min,24h后进行5min的强迫游泳,观察大鼠游泳过程中的不动时间。游泳完毕后将大鼠灌流处死,对全脑组织进行磷酸化ERK1/2(pERK1/2)的免疫组织化学染色及其与酪氨酸羟化酶(TH)在部分核团内的免疫荧光双标细胞。强迫游泳后前额叶皮质、外侧隔区、下丘脑室旁核、海马CA13区、杏仁内侧亚核和皮质亚核、孤束核等脑区/核团中pERK1/2阳性细胞数显著增多;而杏仁中央亚核、下丘脑视上核内的磷酸化ERK1/2蛋白水平下降,阳性细胞数明显减少。免疫荧光双标结果表明,孤束核内部分pERK1/2阳性细胞呈TH免疫反应阳性。上述结果表明,以上脑区/核团内的神经元可能和负性心理应激的中枢调控有关,ERK1/2信号通路参与了其调控过程。此外,孤束核中的儿茶酚胺能神经元可能参与了心理应激的脑内活动。     

大鼠脑缺血对癫痫敏感性和脑内胶质原纤维酸性蛋白免疫反应的影响

本实验采用改良栓线法制备大鼠右侧大脑中动脉 (Middlecerebralartery ,MCA)缺血再灌注模型 ,腹腔注射阈下剂量 (35mg/kg·2d)戊四唑 (pentylenetetrazol,PTZ)制备慢性癫痫点燃模型。通过观察大鼠的行为 ,来检测其癫痫敏感性的改变。分别用硫堇染色、免疫细胞化学方法观察PTZ点燃脑缺血大鼠的相应脑区的神经病理学改变及脑内胶质原纤维酸性蛋白 (gliafibrillaryacidicprotein ,GFAP)免疫反应活性 (immunoreactivity,IR)的变化。结果显示 :脑缺血后大鼠癫痫敏感性明显增强 (P <0 0 5 )。右背侧海马CA1、CA3 区锥体细胞、额叶皮质神经元不同程度的脱失 (P <0 0 5 )并出现大量GFAP免疫反应阳性的星形胶质细胞 ,且细胞体积变大 ,突起变长变粗 ,免疫染色强度明显增强 (P <0 0 5 ) ,提示脑缺血大鼠癫痫敏感性增强 ,可能与海马及额叶皮质的神经元脱失及星形胶质细胞活化增生有关。     

慢性应激对大鼠海马Bcl-xl表达的影响及应激后的变化

目的:探讨慢性应激对大鼠海马神经元Bcl-xl蛋白表达的影响及其应激后的变化。方法:采用慢性强迫冰水游泳制作动物模型。运用open-field法观察大鼠行为学的变化,运用免疫组织化学方法观察大鼠海马DG区、CA3区Bcl-xl的变化。结果:与对照组相比,实验组1大鼠海马CA3区齿状回(DG)区Bcl-xl平均灰度值显著增加(t=4.69,P<0.05和t=3.77,P<0.01),实验组2平均灰度值与对照组2相比同样增加(t=3.35,P<0.05和t=3.30,P<0.05)。结论:慢性应激使大鼠海马Bcl-xl表达降低,应激三十天后,其表达仍低于对照组。     

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。     

Effect of tibolone administration on central and peripheral levels of allopregnanolone and beta-endorphin in female rats

OBJECTIVE: We evaluated the effects of tibolone oral administration on neuroendocrine function by investigating the modulation exerted by tibolone administration on allopregnanolone and central and peripheral beta-endorphin (beta-EP) levels in ovariectomized rats. DESIGN: Female Wistar rats (N = 64) were included: 48 rats were ovariectomized, 8 cycling rats were included as controls, and 8 cycling rats were treated with placebo. The ovariectomized animals were divided into six groups: untreated rats and those that received 14-day oral treatment with either placebo, estradiol valerate (E2V) 0.05 mg/kg/d, or tibolone (0.1, 0.5, or 2 mg/kg/d. beta-EP levels were assessed in the frontal lobe, parietal lobe, hippocampus, hypothalamus, anterior pituitary, neurointermediate pituitary, and plasma, whereas allopregnanolone levels were measured in the frontal lobe, parietal lobe, hippocampus, hypothalamus, anterior pituitary, adrenal glands, and serum. RESULTS: The administration of tibolone (0.5 and 2 mg/kg/d) in ovariectomized rats induces a significant increase of allopregnanolone in the frontal lobe, parietal lobe, hippocampus, hypothalamus, whereas in serum a significant increase of allopregnanolone occurs only with the dose of 2 mg/kg/d, a significant decrease in allopregnanolone levels occurs in the adrenal glands. No changes occurred in the anterior pituitary. Tibolone doses of 0.5 and 2 mg/kg/d induced a significant increase in beta-EP content in the frontal lobe, hypothalamus, and neurointermediate lobe; and, at doses of 2 mg/kg/d, in the parietal lobe, anterior pituitary, and plasma, without changes in the hippocampus. Compared with E2V, 0.5 mg/kg/d tibolone showed a similar effect on allopregnanolone and beta-EP in most brain regions. CONCLUSIONS: Tibolone administration affects beta-EP and allopregnanolone levels, playing a role as a neuroendocrine modulator.     

金雀异黄酮对去卵巢大鼠脑抗氧化作用的影响

目的研究金雀异黄酮对去卵巢大鼠大脑抗氧化作用的影响,为使用植物雌激素防治女性更年期后老年性痴呆提供依据。方法40只3月龄雌性SD大鼠,随机分为假手术组、去卵巢对照组、金雀异黄酮组和苯甲酸雌二醇组,给予相应手术和治疗。术后6周分析大鼠额叶、颞叶、海马和基底前脑的SOD和MDA值。结果假手术组颞叶和海马的SOD值低于基底前脑(P<0.05);额叶和颞叶的MDA值高于海马和基底前脑(P<0.05);去卵巢对照组基底前脑的SOD值显著低于假手术组、金雀异黄酮组和苯甲酸雌二醇组(P<0.05),MDA值显著高于假手术组、金雀异黄酮组和苯甲酸雌二醇组(P<0.05);假手术组、金雀异黄酮组及苯甲酸雌二醇组之间SOD值和MDA值差异无统计学意义(P>0.05)。结论去卵巢对照组大鼠基底前脑抗氧化能力显著降低,氧化损伤程度显著升高,金雀异黄酮替代治疗可增加去卵巢大鼠基底前脑的抗氧化能力,降低基底前脑的氧化损伤,可用于女性更年期后老年性痴呆的防治。     

Effect of Imipramine and Prolyl Endopeptidase Inhibitor Benzyloxycarbonyl-Methionyl-2(S)-Cyanopyrrolidine on Activity of Proline-Specific Peptidases in the Brain of Rats with Experimental Anxious-Depressive Syndrome

Activities of prolyl endopeptidase and dipeptidyl peptidase IV in the frontal cortex, hypothalamus, nucleus accumbens, striatum, and hippocampus were measured in rats with the experimental anxious-depressive syndrome induced by treatment with a dipeptidyl peptidase IV inhibitor during the early postnatal period (days 5-18). Prolyl endopeptidase activity was elevated in the frontal cortex, hypothalamus, and nucleus accumbens. Increased activity of dipeptidyl peptidase IV was observed in the hypothalamus and striatum. Norepinephrine/serotonin reuptake inhibitor, imipramine, and noncompetitive prolyl endopeptidase inhibitor, benzyloxycarbonyl-methionyl-2(S)-cyanopyrrolidine, were shown to abolish depression-like behavior of animals in the forced swimming test. These compounds had a normalizing effect on activities of prolyl endopeptidase and dipeptidyl peptidase IV in brain structures of rats.     

The effect of hypoxia on monoamine levels in discrete regions of aged rat brain

Aged rats were exposed to 10% oxygen for 2, 13, and 36 hr. Norepinephrine levels in cerebral cortex, hypothalamus, hippocampus, midbrain, cerebellum, ponsmedulla and dopamine levels in striatum were determined after each exposure. While there was no significant change in monoamine levels in brain regions after 2 hr, norepinephrine concentration in hypothalamus and midbrain decreased significantly after 13 hr of hypoxia. After 36 hr in a hypoxic environment, levels of the monoamines in brain regions were similar to the controls. This would suggest NE metabolism is most vulnerable to hypoxia in two regions of the aged brain. The precise mechanism of these changes is unknown, but they suggest both a vulnerability and an adaptive recovery of central adrenergic metabolism by the aged brain under hypoxia.     

慢性强迫游泳应激抑郁模型大鼠海马钙离子浓度和c-fos表达的改变

目的:观察慢性强迫游泳应激模型大鼠海马区[Ca2+]i和c-fos/Fos的变化,探讨慢性应激抑郁症与海马相关的发病机制。方法:选用雄性成年Wistar大鼠80只,将大鼠随机分为正常对照组(n=19)、急性对照组(n=12)和模型组(n=49),建立慢性强迫游泳应激抑郁模型,通过糖水偏好实验和开场实验对大鼠进行行为学测试。采用荧光分光光度法测定海马内[Ca2+]i浓度,免疫印迹技术和逆转录-聚合酶链式反应检测Fos和c-fos的表达变化。结果:与正常对照组大鼠相比较:(1)模型组大鼠相对糖水消耗量、糖水偏好百分比、直立次数和体重增长率均降低(P0.01,P0.05);(2)模型组大鼠各个时间点海马神经元[Ca2+]i增高(P0.01);(3)模型组大鼠海马Fos在应激后(0.5,1,2,4h)表达增强(P0.01),c-fosmRNA在应激后(0.5,1,2,4h)转录增强(P0.01)。与急性对照组相比较,模型组Fos蛋白表达高峰提前,表达量降低(P0.05)。结论:海马[Ca2']i及c-fos/Fos的表达变化,可能参与了抑郁症的发病过程。     

Effects of age and stress on regional noradrenaline metabolism in the rat brain

Levels of noradrenaline (NA) and its major metabolite, 3-methoxy-4-hydroxyphenylethyleneglycol sulfate (MHPG-SO₄), were determined in eight brain regions of non-stressed rats at 2, 10 and 15 months of age, and of rats at 2 and 15 months of age stressed by immobilization for 3 hours. The NA levels in older rats were significantly lower in the hypothalamus, pons+med.obl. and midbrain, and higher in the amygdala, thalamus, hippocampus and cerebral cortex as compared to those of 2 month old rats. The MHPG-SO₄, levels in the older rats were significantly lower in the hypothalamus, amygdala, pons+med.obl. and midbrain, and higher only in the cerebral cortex than those in 2 month old rats. Immobilization stress caused significant increases in NA turnover in all brain regions of both 2 and 15 month old rats. Age-related difference in the degree of stress-induced change in NA metabolism was found only in the hypothalamus; the increase of MHPG-SO₄ by stress was greater in 2 month old rats than in 15 month old rats, although both age groups of rats showed the same degree of NA reduction by stress. These data suggest that brain NA metabolism changes in an age-related fashion, and that apparent regional differences exist in the pattern of these changes. Specifically, it appears that there is an age-related difference in the response of noradrenergic neurons to stress in the hypothalamus.     

Exposure to novelty and forced swimming evoke stressor-dependent changes in extracellular GABA in the rat hippocampus

In the hippocampus, a brain structure critically important in the stress response, GABA controls neuronal activity not only via synaptic inhibition, but also via tonic inhibition through stimulation of extrasynaptic GABA receptors. The extracellular level of GABA may represent a major determinant for tonic inhibition and, therefore, it is surprising that its responsiveness to stress has hardly been investigated. To clarify whether hippocampal extracellular GABA levels change in response to acute stress, we conducted an in vivo microdialysis study in rats. We found that dialysate GABA levels respond to various neuropharmacological manipulations such as reuptake inhibition, elevated concentrations of K(+), tetrodotoxin and baclofen, indicating that a large proportion of hippocampal extracellular GABA depends on neuronal release and that GABA re-uptake plays a role in determining the extracellular levels of this neurotransmitter. Next, rats were exposed to a novel cage or to forced swimming in 25 degrees C water. Interestingly, these two stressors resulted in opposite effects. Novelty caused a fast increase in GABA (120% of baseline), whereas forced swimming resulted in a profound decrease (70% of baseline). To discriminate between the psychological and physical aspects (i.e. the effects on body temperature) of forced swimming, another group of animals was forced to swim at 35 degrees C. This stressor, like novelty, caused an increase in hippocampal GABA, suggesting a stimulatory effect of psychological stress. The effects of novelty could not be blocked by the corticotropin-releasing factor receptor antagonist D-Phe-CRF(12-41). These results are the first to demonstrate stressor-dependent changes in hippocampal extracellular GABA; an observation which may be of particular significance for GABAergic tonic inhibition of hippocampal neurons.