血管性痴呆小鼠海马结构SS及CCK蛋白表达的改变

目的:观察血管性痴呆小鼠海马结构生长抑素(SS)和胆囊收缩素(CCK)阳性神经元的数量变化,探讨血管性痴呆的发生机制。方法:复制小鼠血管性痴呆模型,利用Y-迷宫检测血管性痴呆模型小鼠学习记忆能力,采用ABC免疫组织化学方法,研究血管性痴呆小鼠与正常小鼠海马结构SS和CCK阳性神经元数量的变化。结果:血管性痴呆小鼠比正常小鼠Y-迷宫学习记忆训练次数明显增多,差异有统计学意义;海马结构CA1区、CA3区及齿状回(DG)区SS和CCK阳性神经元的数量明显减少,差异有统计学意义。结论:血管性痴呆的发生可能与海马结构CA1区、CA3区及齿状回(DG)区SS和CCK阳性神经元的数量明显减少有关。     

EGCG对血管性痴呆Wistar大鼠学习记忆功能及Bax、Bcl-2蛋白表达的影响

目的探讨(-)表没食子儿茶素没食子酸酯(epigallocatechin-3-gallate,EGCG)对血管性痴呆大鼠学习记忆能力及Bax、Bcl-2蛋白表达的影响。方法 3-4月龄Wistar大鼠70只,用线栓法建立血管性痴呆(VD)动物模型,随机分为5组:假手术组,模型组、对照组、EGCG高剂量治疗组(6mg/kg/d)、EGCG低剂量治疗组(2mg/kg/d)。水迷宫实验检测动物的学习记忆能力,免疫组化、Wstern Blot方法检测Bax、Bcl-2蛋白表达。结果水迷宫结果显示:模型组动物水迷宫潜伏期较假手术组明显延长(P<0.05),EGCG高低剂量治疗组VD动物的水迷宫潜伏期较模型组明显缩短(P<0.05)。免疫组化和Western Blot结果显示:与假手术组相比模型组动物Bax蛋白表达上升(P<0.05),Bcl-2(P<0.05)蛋白表达下降,EGCG治疗组Bax蛋白表达下降(P<0.01),Bcl-2蛋白表达升高(P<0.01)。结论 EGCG明显改善VD动物模型的学习记忆能力,可能与诱导脑组织Bcl-2蛋白表达及降低Bax蛋白表达量有关。     

银杏叶提取物对血管性痴呆大鼠海马突触素表达的影响

目的：研究银杏叶提取物(EGb761)对血管性痴呆模型大鼠海马突触素表达的影响。方法:以双侧颈总动脉反复夹闭再通同时腹腔注射硝普钠建立血管性痴呆模型大鼠，采用Morris 水迷宫和免疫组化方法分别观察大鼠空间学习记忆能力及海马突触素(SYN)表达情况。结果:模型组大鼠在1月、2月和4月不同时点测得的Morris水迷宫逃避潜伏期(EL)均较假手术组明显延长(P<0.01)，药物组EL均显著短于模型组，但仍长于假手术组(P<0.05或P<0.01)；模型组海马SYN表达弱于假手术组，而药物组海马SYN表达高于模型组(P<0.01)。结论:EGb761增加海马结构SYN表达可能是其改善VD大鼠学习记忆障碍的重要机制。     

牛磺酸锌对睡眠剥夺大鼠脑认知功能的影响及机理

目的:探索补锌对睡眠剥夺(SD)后大鼠脑认知功能的影响及机制。方法:采用小平台水环境法制作大鼠SD模型,3天后通过Y-型迷宫行为测试结合NADPH-d组化与免疫组化ABC法,分别观察大鼠海马结构不同亚区内一氧化氮合酶(NOS)活性与神经元型一氧化氮合酶(nNOS)蛋白表达水平的变化。结果:SD组大鼠迷宫实验学会次数(89.3±25.3)较正常对照组大鼠(67.1±29.3)增加(t=1.81,P<0.05),补牛磺酸锌(5.9g/kg饲料牛磺酸锌水平)组大鼠的迷宫实验学会次数(71.9±21.4)较SD组减少(t=1.66,P<0.05)。与正常对照组大鼠海马结构的NOS(CA1:32.6±2.1;CA3:20.5±1.8;DG:27.5±1.8)活性和nNOS蛋白(CA1:68.3±4.1;CA3:41.7±2.5;DG:44.4±2.8)表达相比,SD组大鼠海马结构各亚区NOS(CA1:14.8±1.2;CA3:10.6±1.0;DG:13.1±1.3)活性和CA1区与齿状回nNOS蛋白(CA1:51.3±3.6;DG:41.6±2.7)表达减少(P<0.05),CA3区nNOS蛋白变化不明显(38.1±4.8,P>0.05)。与SD组大鼠相比,补牛磺酸锌组大鼠海马结构不同亚区内的NOS表达增加(CA1:27.2±2.8;CA3:15.3±1.6;DG:21.8±1.9,P<0.05),CA1区的nNOS蛋白表达增加(60.1±3.4,P<0.05),CA3和齿状回nNOS表达变化不明显(CA3:39.6±4.9;DG:42.8±3.5,P>0.05)。结论:牛磺酸锌对大鼠学习记忆功能有促进作用,其机理可能与上调海马结构NOS、nNOS表达水平有关。     

多奈哌齐对血管性痴呆小鼠学习记忆及海马Akt、p-Akt表达的影响

目的探讨盐酸多奈哌齐对血管性痴呆(VD)小鼠学习记忆能力及对海马Akt、p-Akt表达的调节作用。方法采用双侧颈总动脉反复缺血-再灌注法制备小鼠VD模型。90只雄性昆明小鼠随机分为3组,假手术组(30只)、模型组(30只)及盐酸多奈哌齐组(30只)。在术后第29天、第30天,经跳台试验和水迷宫试验进行行为学测试,用免疫组化和western blot方法检测各组小鼠海马Akt、p-Akt的表达变化。结果小鼠的学习和记忆能力VD模型组明显低于假手术组,而盐酸多奈哌齐治疗组明显高于VD模型组小鼠(0.05);免疫组化和Western blot结果发现,小鼠海马CAl区Akt、p-Akt蛋白相对表达水平VD模型组明显低于假手术组,而盐酸多奈哌齐治疗组显著高于VD模型组(0.05)。结论盐酸多奈哌齐改善血管性痴呆(VD)小鼠学习和记忆功能可能与上调VD小鼠Akt、p-Akt的表达相关。     

银杏叶提取物预处理对VD模型大鼠海马CA1区P-GP和GLT-1表达的影响

目的:探讨银杏叶提取物(EGB761)预处理对血管性痴呆(VD)模型大鼠海马CA1区P-糖蛋白(P-GP)及谷氨酸转运体1(GLT-1)的影响。方法:大鼠分为假手术组、模型组和EGB761预处理组。EGB761预处理组在造模前7 d给予EGB761生理盐水混悬液灌胃,假手术组和模型组给予等体积的生理盐水灌胃。采用重复夹闭双侧颈总动脉(CCA)同时腹腔注射硝普钠溶液方法复制VD大鼠模型。Morris水迷宫检测大鼠空间学习记忆能力,用神经颗粒素(Ng)/P-GP和胶质细胞酸性蛋白(GFAP)/GLT-1免疫荧光双标法,观察海马CA1区神经元P-GP和胶质细胞GLT-1表达水平的变化,Western Blot技术检测VD大鼠海马区P-GP和GLT-1蛋白的表达量。结果:(1)Morris水迷宫检测显示,与假手术组相比,模型组大鼠的逃逸潜伏期(Escape latency,EL)明显延长(P0.01),而EGB761预处理组大鼠EL明显缩短(P0.01)。(2)阳性细胞计数观察到,与假手术组相比,模型组海马CA1区Ng/P-GP的阳性细胞数明显减少,GFAP/GLT-1的阳性细胞数则显著增多(P0.01),EGB761预处理组海马CA1区Ng/P-GP和GFAP/GLT-1的阳性细胞数较模型组均明显增多(P0.01)。(3)积分光密度值测定观察到,模型组和EGB761预处理组的Ng/P-GP和GFAP/GLT-1阳性细胞的IOD值较假手术组均明显增大(P0.01);EGB761预处理组的Ng/P-GP和GFAP/GLT-1阳性细胞IOD值均显著高于模型组(P0.01)。(4)Western Blot分析结果显示,模型组和EGB761预处理组大鼠海马CA1区P-GP和GLT-1蛋白表达的灰度值均比假手术组增大(P0.01),EGB761预处理组大鼠海马CA1区P-GP和GLT-1蛋白表达的灰度值均显著大于模型组(P0.01)。结论:EGB761预处理可能通过上调VD模型大鼠海马CA1区P-GP和GLT-1的表达来预防VD的发生。     

银杏叶提取物对血管性痴呆大鼠空间学习记忆和海马NMDAR1表达的影响

目的:观察银杏叶提取物(EGb761)对血管性痴呆(VaD)大鼠空间学习记忆和海马N-甲基-D-天冬氨酸型离子型谷氨酸受体1型亚单位(NMDAR1)表达的影响。方法:采用四血管阻断法制备VaD大鼠模型,设立假手术组、模型组、尼莫地平组(10 mg/kg/d,灌胃30 d)和银杏叶提取物组(50 mg/kg/d,灌胃30 d)。利用Morris水迷宫检测大鼠空间学习记忆的改变,采用免疫组化和Western blot技术检测大鼠海马神经元NMDAR1蛋白水平的变化,实时荧光定量PCR技术检测大鼠海马NMDAR1的mRNA表达变化。结果:与假手术组相比,模型组大鼠水迷宫逃避潜伏期延长,撤后台靶象限平均探索次数减少(P<0.05),银杏叶提取物明显改善了VaD大鼠在Morris水迷宫中的学习记忆成绩(P<0.05);假手术组、尼莫地平组与银杏叶提取物组之间比较无统计学差异(P>0.05)。模型组大鼠的NMDAR1蛋白及其mRNA在海马CA1区的表达水平较假手术组明显降低(P<0.05);银杏叶提取物组大鼠海马的NMDAR1蛋白及mRNA表达水平较模型组明显升高(P<0.05)。结论:银杏叶提取物可以减轻脑缺血再灌注对海马CA1区神经元的损伤,这可能与上调海马组织内NMDAR1蛋白及mRNA的表达密切相关。     

银杏叶提取物对1型糖尿病大鼠认知功能及海马神经细胞凋亡的影响

目的： 探讨银杏叶提取物(EGB)对1型糖尿病脑病大鼠海马神经细胞的保护机制。方法: 36只SD雄性大鼠随机分为正常对照组（C组）、糖尿病模型组(DM组)、银杏叶提取物治疗组（EGB组）。用链脲佐菌素（STZ）腹腔注射建立糖尿病动物模型,EGB组腹腔注射银杏叶提取物注射液,其余2组给予同等体积的生理盐水。于12周末通过Morris水迷宫法评价各组大鼠学习记忆能力并测定血清中的血糖和胰岛素浓度;用Image-Pro Plus 6.0图像分析技术检测大鼠海马组织神经细胞密度;Western blotting和免疫组织化学法检测其Bax、Bcl-2和caspase-3蛋白的表达。结果: DM组大鼠血糖浓度(P<0.01)、海马神经细胞中Bax(P<0.01)、caspase-3(P<0.01)蛋白的表达、Bax/ Bcl-2比例 (P<0.01)及Morris水迷宫潜伏期(P<0.01)均高于C组,而胰岛素水平(P<0.01)、海马CA1和CA2区域的神经细胞密度(P<0.05) 及Morris水迷宫搜索策略能力(P<0.01)均低于C组。EGB干预治疗后大鼠胰岛素水平(P<0.05)、海马CA1和CA2区域的神经细胞密度(P<0.05) 及Morris水迷宫搜索策略能力(P<0.01)均高于DM组,而血糖浓度(P<0.01)、海马组织中Bax(P<0.05)、caspase-3(P<0.05)蛋白的表达、Bax/ Bcl-2比例 (P<0.01) 及Morris水迷宫潜伏期(P<0.05)均低于DM组。各实验组大鼠Bcl-2蛋白的表达没有明显变化。结论: 银杏叶提取物提高糖尿病大鼠的空间学习记忆能力,可能通过减少Bax、caspase-3蛋白表达、降低Bax/ Bcl-2比例,从而减少神经细胞的凋亡,提高神经细胞密度而发挥作用。提示通过有效调节神经元凋亡相关基因是EGB治疗糖尿病脑病的的重要作用机制之一。     

银杏叶提取物对AD模型小鼠海马谷氨酸转运体GLAST表达的影响

目的探讨银杏叶提取物对AD模型小鼠海马谷氨酸转运体GLAST表达的影响。方法采用双侧海马CA1区注射Aβ_(1-42)法测定正常对照组、AD模型组、AD+银杏叶提取物低剂量组(30 mg·kg~(-1)·day~(-1))、中剂量组(60 mg·kg~(-1)·d~(-1))、高剂量组(120 mg·kg~(-1)·d~(-1))动物海马中GLAST的变化。结果经银杏叶提取物处理后,模型组动物存活率增加;小鼠海马组织中Aβ_(1-42)阳性沉积明显减少,且高剂量组减少最为明显;AD模型组GLAST阳性表达明显减少(P0.05);银杏叶提取物处理组小鼠海马区GLAST阳性表达出现增加,银杏叶提取物中剂量组GLAST阳性表达增加最为显著(P0.05)。结论银杏叶提取物具有缓解Aβ诱导神经毒性的作用,对AD模型小鼠海马中谷氨酸转运体GLAST具有调节和保护作用。     

亚甲蓝对APP/PS1转基因小鼠学习记忆及海马结构内GFAP表达的影响

目的:观察亚甲蓝对APP/PS1转基因小鼠学习记忆及胶质纤维酸性蛋白(Glial fibrillary acidic pro-tein,GFAP)在海马结构表达变化的影响。方法:20只3月龄APP/PS1小鼠,随机分2组,每组10只,对照组:自由饮水;治疗组:根据小鼠饮水量将亚甲蓝加入日常饮水中(25 mg/kg/d)连用4个月至7月龄。水迷宫测试观察其行为学的改变,免疫组化、Western Blot和TUNEL染色法观察GFAP在海马结构的表达及神经元的凋亡情况。结果:水迷宫测试结果显示亚甲蓝喂养组APP/PS1转基因小鼠第2～4 d的平均潜伏期显著低于对照组小鼠的潜伏期,说明治疗组与对照组相比在7个月时出现明显差异(P<0.05);免疫组化和Western结果显示治疗组海马结构内的GFAP在APP/PS1转基因小鼠的表达下调(P<0.05)。TUNEL染色法显示治疗组海马CA1、CA3区和齿状回TUNEL阳性细胞数较对照组明显减少(P<0.05)。结论:亚甲蓝能够下调APP/PS1小鼠海马结构内GFAP蛋白的表达,并通过抑制海马结构神经元的凋亡,提高APP/PS1小鼠的认知能力。     

急性缺氧小鼠海马CAl区NOS活力和nNOS蛋白表达的时程变化

目的:观察急性缺氧小鼠海马CAl区一氧化氮合酶(NOS)和神经元型一氧化氮合酶(nNOS) 阳性神经元的时程变化,探讨NO在脑缺氧中的作用并为抗脑缺氧提供依据。方法:复制小鼠急性缺氧模型,采用NADPH-d组织化学和nNOS免疫组织化学方法,研究急性缺氧后不同时程点小鼠海马CAl区NADPH-d 和nNOS阳性神经元数量的变化。结果:与正常对照组相比较,急性缺氧后0.5h组小鼠海马CAl区NADPH-d 和nNOS阳性神经元的数量无明显变化,差异无显著性(P>0.05),3h、6h和12h组逐渐增多并于12h升高达到最高峰,差异有显著性(P<0.05),而于24h后开始降低,48h恢复正常。结论:急性缺氧后早期海马CAl区NOS和nNOS水平明显增多,NO在缺氧所致早期脑损伤中起重要作用。     

补阳还五汤对血管性痴呆大鼠海马GluR1蛋白及mRNA表达的影响

目的:观察补阳还五汤对血管性痴呆(VD)大鼠海马α-氨基羟甲基恶丙酸受体(AMPA)GluR1亚单位蛋白及mRNA表达的影响,探讨补阳还五汤治疗VD的机制。方法:四血管阻断法制备VD大鼠模型。设立假手术组、VD模型组、尼莫地平组(20mg·kg-1.d-1,灌胃30d)和补阳还五汤治疗组(50g·kg-1.d-1灌胃30d)。Morris水迷宫检测大鼠学习记忆能力的改变,免疫组化和Westernb lotting技术检测大鼠海马神经元GluR1蛋白的变化,实时荧光定量PCR技术检测大鼠海马GluR1mRNA表达的变化。结果:与假手术组相比,VD模型组大鼠逃避潜伏期延长和平均探索次数减少(P0.05);补阳还五汤明显改善了模型大鼠上述学习、记忆成绩(P0.05);假手术组、尼莫地平组与补阳还五汤治疗组之间差异无显著(P0.05)。VD模型组大鼠的GluR1蛋白及其mRNA表达水平较假手术组明显降低(P0.05);补阳还五汤治疗组大鼠海马的GluR1蛋白及其mRNA表达水平较模型组的表达明显升高(P0.05);假手术组、尼莫地平组与补阳还五汤治疗组之间差异无显著(P0.05)。结论:补阳还五汤可以改善VD大鼠学习记忆能力,其机制可能与减轻脑缺血再灌注对海马CA1区神经元的损伤及恢复海马组织GluR1蛋白及其mRNA的表达有关。     

血管性痴呆大鼠海马Ng及其磷酸化水平的动态变化

目的:观察血管性痴呆(VD)模型大鼠海马神经颗粒素(Ng)及其磷酸化水平的动态变化,探讨Ng在VD学习记忆功能障碍中的作用及其机制。方法:采用双侧颈总动脉夹闭再灌注同时腹腔注射硝普纳建立血管性痴呆模型,在15d,1,2,4个月等时间点,采用Morris水迷宫和免疫荧光方法分别观察大鼠空间学习记忆能力及海马Ng及其磷酸化水平的变化。结果:模型组大鼠各时间点的逃逸潜伏期(EL)比假手术组均明显延长(P0.01);海马CA1区Ng及其磷酸化Ng免疫阳性神经细胞数表达较假手术组明显减少(P0.01,P0.05),而且随造模手术后时间的延长,以上变化逐渐加重。齿状回仅在2个月和4个月时间点的免疫阳性神经细胞数比假手术组显著减少(P0.01,P0.05)。结论:模型组大鼠的空间学习记忆功能障碍可能与海马(特别是CA1区)的Ng及其磷酸化Ng表达水平持续降低有关。     

黄精口服液对血管性痴呆大鼠学习记忆与海马突触可塑性的影响

应用Morris水迷宫、免疫组织化学法、透射电镜、图像分析和细胞形态计量学等技术,观察黄精口服液对血管性痴呆大鼠学习记忆能力和突触可塑性的影响。结果显示: (1)术后3. 5个月(即给药2. 5个月)痴呆+黄精口服液组大鼠平均逃避潜伏期较血管性痴呆组和痴呆+生理盐水组大鼠明显缩短(P<0. 05); (2)血管性痴呆组和痴呆+生理盐水组大鼠海马结构突触膜糖蛋白免疫反应产物校正灰度值比空白对照组明显降低;痴呆+黄精口服液组大鼠海马结构突触膜糖蛋白免疫反应产物校正灰度值高于血管性痴呆组和痴呆+生理盐水组大鼠(P<0. 05);大鼠平均逃避潜伏期与海马结构突触膜糖蛋白免疫反应产物校正灰度值呈负相关。(3)痴呆+黄精口服液组大鼠海马CA1区突触界面曲率增大、突触后致密物增厚、突触活性区增长(P<0.05)。这些结果表明:黄精口服液具有重塑突触结构与功能、改善血管性痴呆SD雌性大鼠学习记忆能力的作用。     

Ginkgo biloba leaf extract improves the cognitive abilities of rats with D-galactose induced dementia

Standardized Ginkgo biloba leaf extract has been used in clinical trials for its beneficial effects on brain functions,particularly in dementia.Substantial experimental evidences indicated that Ginkgo biloba leaf extract (EGB) protected neuronal cells from a variety of insults.We investigated the effect of EGB on cognitive ability and protein kinase B (PKB) activity in hippocampal neuronal cells of dementia model rats.Rats received an intraperitoneal injection of D-galactose to induce dementia.Forty-eight Spraque-Dawley rats were randomly divided into six groups,including the control group,D-galactose group (Gal),low-dose EGB group (EGB-L),mid-dose EGB group (EGB-M),high-dose EGB group (EGB-H) and treatment group.The EGB-L,EGB-M and EGB-H groups were administered with EGB and D-galactose simultaneously.Y-maze,cresyl violet staining,TUNEL assays and immunohistochemistry staining were performed to detect learning and memory abilities,morphological changes in the hippocampus,neuronal apoptosis and the expressing level of phospho-PKB,respectively.Rats in the Gal group showed decreased abilities of learning and memory,and hippocampal pyramidal cell layer was damaged,while EGB administration improved learning and memory abilities.The Gal group exhibited many stained,condensed nuclei and micronuclei,either isolated or within the cytoplasm of cells (39.5±1.4).Apoptotic cells decreased in the groups of EGB-L (35.9±0.9),EGB-M (16.8±1.0) and EGB-H (10.1±0.8),and there were statistical significances compared with the Gal group.Immunoreactivity of phospho-PKB was localized diffusely throughout the cytosol of cells in all groups,while the immunoreactivity of the Gal group was weak.EGB significantly attenuated learning and memory impairment in a dose-dependent manner,while it could decrease the nmber of TUNEL-positive cells,and increase the activity of PKB.Our results demonstrated that EGB attenuated memory impairment and cell apoptosis in galactose-induced dementia model rats by activating PKB.     

补阳还五汤对血管性痴呆大鼠学习记忆功能及海马组织ERK2与CaMKⅡβ蛋白表达的影响

目的:观察补阳还五汤对血管性痴呆(VD)大鼠学习记忆功能及其相关蛋白ERK2与CaMKⅡβ表达的影响。方法:采用Pulsinelli’s4血管阻断法制备VD动物模型,设假手术组、模型组、补阳还五汤组、尼莫地平组,在术后第7d、14d、28d,利用水迷宫试验对各组大鼠进行行为学检测;术后第30d,采用HE染色方法观察海马CA1区形态学变化并进行神经元计数;采用Westernblotting方法观察大鼠CA1区海马组织ERK2与CaMKⅡβ蛋白表达变化。结果:与假手术组比较,模型组大鼠学习与记忆成绩明显下降(P0.05);海马CA1区神经元排列紊乱,出现凝固性坏死,细胞脱失明显;ERK2与CaMKⅡβ蛋白表达显著降低(P0.05)。与模型组比较,补阳还五汤组、尼莫地平组大鼠学习和记忆成绩均明显好转(P0.05);海马CA1区神经元排列整齐,细胞形态正常,脱失不明显,接近假手术组;ERK2与CaMKⅡβ蛋白表达显著增多(P0.05)。结论:补阳还五汤可能通过促进VD大鼠ERK2蛋白和CaMKⅡβ蛋白的表达,从而促进突触构建和学习记忆功能的恢复。     

Acute and delayed restraint stress-induced changes in nitric oxide producing neurons in limbic regions

RATIONALE: Microinjection into the dentate gyrus of the hippocampus of N(omega)-nitro-l-arginine methyl ester hydrochloride (l-NAME), a nitric oxide synthase (NOS) inhibitor, induces antinociceptive effect 5 days after a single restraint episode. The mechanisms of this stress-antinociceptive modulatory effect have not been investigated but may involve plastic changes in the hippocampal formation (HF). OBJECTIVE: The objective of the present study was to investigate possible mechanisms of the stress-modulating effect on antinociception induced by NOS inhibition in the hippocampus. We analyzed the effects of restraint stress on neuronal NOS (nNOS) expression and nicotinamide adenine dinucleotide phosphate-diaphorase histochemical activity (NADPH-d) in the HF and related brain regions. METHODS: Male Wistar rats (n=6-11/group) were submitted to a single (acute stress) or repeated (5 days) episodes of 2-h restraint. Control animals remained in their home cages being all animals daily handled during this period. In the fifth day, animals received unilateral microinjection of l-NAME (150 nmol/0.2 microl) or saline (control) into the dentate gyrus of the dorsal hippocampus (DG). Immediately before and after drug microinjection tail-flick reflex latency or hotplate licking reaction was measured. Animals were killed i. immediately; ii. 5 days after acute stress; or iii. after repeated stress. NADPH-d and nNOS expression were quantified in the HF, caudate-putamen, secondary somatosensorial, entorhinal and piriform cortices and amygdaloid complex. RESULTS: Five days after one or five restraint episodes l-NAME microinjection into the DG elicited antinociceptive effect (analysis of variance [ANOVA], P<0.05). Acute restraint stress induced a significant increase in the density of neurons expressing NADPH-d and nNOS in the amygdaloid nuclei. nNOS expression increased also in the DG and piriform cortex. Five days after a single or repeated restraint stress there was an additional increase in NADPH-d- and nNOS-positive neurons in CA1, CA3, and entorhinal cortex. No changes were seen in non-limbic regions such as the caudate-putamen and secondary somatosensorial cortex. CONCLUSION: The results confirm that the dorsal hippocampus participates in the modulation of stress consequences. They also show that a single stress episode causes acute changes in nitric oxide system in the amygdala complex and delayed modifications in the HF. The delayed (5 days) antinociceptive effect of NOS inhibition in the HF after a single restraint episode suggests that those latter modifications may have functional consequences. It remains to be tested if the acute amygdala and delayed hippocampal changes are causally related.     

Neuronal NADPH-d/NOS expression in the nodose ganglion of severe hypoxic rats with or without mild hypoxic preconditioning

This study aimed to test the hypothesis that mild hypoxic preconditioning (MHPC)-induced NOS expression would attenuate the neuropathological changes in the nodose ganglion (NG) of severe hypoxic exposure (SHE) rats. Thus, the young adult rats were caged in the altitude chamber for 4 weeks prior to SHE for 4 h to gain hypoxic preconditioning. The altitude chamber was used to set the height at the level from 5500 m (0.50 atm; pO2=79 Torr) to 10,000 m (0.27 atm; pO2=43 Torr) for MHPC and SHE, respectively. The experimental animals were allowed to survive for 0, 7, 14, 30 and 60 successive days, respectively. Nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry and neuronal nitric oxide synthase (nNOS) immunohistochemistry were used to detect NADPH-d/nNOS reactivity in the NG at various time points following hypoxic exposure. The present results showed that about 38% of the neurons in the NG displayed NADPH-d/nNOS positive [NADPH-d/nNOS(+)] in normoxic rats. In SHE rats, a peak in the percentage (71%) and staining intensity (230%) of NADPH-d/nNOS(+) nodose neurons at 0 day, which then gradually decreased at 7-60 days. About 25% of the nodose neurons died 60 days after SHE. However, in MHPC rats subjected to SHE, NADPH-d/nNOS(+) neurons peaked in the percentage (51%) and staining intensity (171%) at 0 day, which then decreased at 7-60 days. In addition, neuronal survival was markedly increased by MHPC. These results suggested that MHPC might have a neuroprotective effect that reduces the susceptibility of the nodose neurons to NOS mediated neuropathy subsequent to SHE.