多奈哌齐对血管性痴呆大鼠海马CA_1区NF-κB及COX-2表达的影响

目的观察血管性痴呆(VD)大鼠行为学改变及海马CA1区核转录因子-κB(NF-κB)、环氧化酶-2(COX-2)表达的变化及多奈哌齐干预效果。探讨多奈哌齐对VD大鼠脑保护作用的可能机制。方法双侧颈总动脉结扎法建立血管性痴呆大鼠动物模型,120只雄性SD大鼠随机分为:假手术4w、8w组、模型4w、8w组;多奈哌齐治疗4w、8w组。Morris水迷宫实验检测认知行为学改变,免疫组织化学法检测大鼠海马CA1区NF-κB、COX-2的表达。结果多奈哌齐可以显著提高血管性痴呆大鼠的学习记忆力和反应能力;模型组和多奈哌齐治疗组NF-κB、COX-2表达均较假手术组明显增高(P0.01),但多奈哌齐治疗组两者表达较模型组明显降低(P0.01)。结论多奈哌齐可以明显改善血管性痴呆大鼠的行为学症状,可能是抑制大鼠脑组织NF-κB、COX-2的表达发挥其脑保护作用。     

盐酸多奈哌齐对拟血管性痴呆大鼠海马神经元的保护机制

目的 探讨盐酸多奈哌齐对拟血管性痴呆(VD)大鼠海马神经元的保护机制.方法 采用双侧颈总动脉反复夹闭、再通,并腹腔注射硝普钠法制备VD模型后,用盐酸多奈哌齐溶液灌胃;用Y-型迷宫试验观察其行为学改变;用免疫组化技术检测大鼠海马神经元N-甲基-D-天门冬氨酸受体1(NR1)的表达; 分别采用5 5'二硫代二硝基苯甲酸(DTNB)法及紫外分光光度法测定其谷胱甘肽过氧化物酶(GSH-PX)、过氧化氢酶( CAT)活力,并与对照组比较.结果 与VD对照组比较,盐酸多奈哌齐组大鼠学习、记忆成绩明显提高(均P＜0.01);海马CA1区NR1表达明显降低(P＜0.01); GSH-PX、CAT活性明显增高(均P＜0.05).结论 盐酸多奈哌齐可能通过降低NR1的表达,提高GSH-PX、CAT的活力来保护VD大鼠海马神经元.     

盐酸多奈哌齐对血管性痴呆模型小鼠海马神经元ERK表达的影响

目的探讨盐酸多奈哌齐对血管性痴呆(VD)模型小鼠海马神经元中细胞外信号调节激酶(ERK)表达的影响。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。将小鼠随机分为假手术组、模型组及盐酸多奈哌齐治疗组,药物组给予盐酸多奈哌齐灌胃治疗。术后第29、30天,采用跳台试验和水迷宫试验对各组小鼠进行行为学成绩测试,采用免疫组化法观察各组小鼠海马神经元ERK表达的变化。结果盐酸多奈哌齐可明显改善VD模型小鼠学习、记忆成绩(P<0.05)。模型组小鼠海马CA1区ERK1、ERK2表达及海马CA3区p-ERK表达较假手术组及治疗组减少(均P<0.05)。结论盐酸多奈哌齐通过增加乙酰胆碱含量,后者作用于毒蕈碱乙酰胆碱受体(M受体)激活ERK,从而有助于改善学习和记忆功能。海马神经元内ERK的表达减少可能参与了VD的发病机制。     

盐酸多奈哌齐对血管性痴呆小鼠海马ERK1及ERK2表达变化的影响

目的:探讨盐酸多奈哌齐对血管性痴呆(VD)小鼠海马中细胞外信号调节激酶(ERK1、ERK2)表达变化的影响。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。将小鼠随机分为假手术组、模型组及药物组,药物组给予盐酸多奈哌齐灌胃治疗。术后第29、30天,经跳台试验和水迷宫试验对各组小鼠进行行为学成绩测试,用免疫组化方法观察各组小鼠海马CA1区ERK1、ERK2的表达变化。结果:盐酸多奈哌齐明显改善了VD小鼠学习、记忆成绩(p<0.05)。模型组小鼠海马CA1区ERK1、ERK2表达较假手术组及治疗组减少,均有显著性差异(p<0.05)。结论:ERK1、ERK2的表达减少可能参与了血管性痴呆的发病机制,盐酸多奈哌齐通过增加乙酰胆碱含量,后者作用于毒蕈碱乙酰胆碱受体(M受体)激活ERK,有助于改善学习和记忆功能。     

盐酸多奈哌齐对血管性痴呆小鼠学习和记忆能力的影响

目的观察盐酸多奈哌齐对脑缺血-再灌注后血管性痴呆小鼠不同时间点学习、记忆能力和海马CA1区病理变化的影响。方法雄性昆明小鼠250只,采用双侧颈总动脉反复缺血-再灌注的方法制备血管性痴呆(VD)模型,随机分为假手术组、模型组和多奈哌齐治疗组。应用Morris水迷宫实验、跳台实验进行行为学测试,HE染色观察海马病理表现及盐酸多奈哌齐对其的影响。结果术后4周时,模型组小鼠的学习、记忆成绩均明显劣于假手术组小鼠(P<0.05),病理改变较假手术组严重,这一变化持续至术后8周仍未恢复。盐酸多奈哌齐治疗组在术后4周和8周时,其学习、记忆能力和海马CA1区病理表现较模型组均有明显改善(P<0.05)。结论脑缺血-再灌注可导致小鼠海马CA1区神经元持续进行性损害,伴学习、记忆能力障碍;盐酸多奈哌齐对脑缺血-再灌注诱发的VD小鼠有一定治疗作用。     

戊四氮点燃癫癎大鼠空间学习记忆改变及海马NR2B表达

目的观察戊四氮点燃癫癎大鼠空间学习记忆功能变化及海马NMDA2型受体(NR2)B亚单位(NR2B)表达,探讨二者的关系及PTZ致癎大鼠认知障碍发生的分子机制。方法采用戊四氮(PTZ)慢性癫癎(CE)模型,Y-迷宫对两组大鼠进行行为学检测,免疫组织化学方法观察两组大鼠海马CA3区NR2B表达的变化,反转录多聚酶链反应(RT-PCR)方法检测大鼠海马NR2B mRNA的表达。结果癫癎组大鼠空间学习记忆能力受损;其海马CA3区NR2B阳性细胞较对照组明显减少(P<0.01),同时伴有海马NR2B mRNA表达下降(P<0.01)。结论戊四氮点燃癫癎大鼠空间学习记忆受损可能与海马神经元NR2B的表达减少有关。     

盐酸多奈哌齐对血管性痴呆小鼠海马CA1区Calpain 1表达的影响

目的 探讨盐酸多奈哌齐对反复脑缺血-再灌注后血管性痴呆(VaD)小鼠海马CA1区Calpain 1表达的影响.方法 采用双侧颈总动脉反复缺血-再灌注合并尾端放血的方法制备VaD动物模型.分别于术后第4周和第8周测试小鼠的学习和记忆成绩,应用免疫组化方法观察海马CA1区Calpain 1表达的变化及盐酸多奈哌齐对其的影响.结果 术后4周和8周时模型组小鼠的学习、记忆成绩均明显劣于假手术组小鼠(P<0.01),海马CA1区Calpain 1表达分别是(0.090 0±0.010 0)和(0.102 0±0.008 4),显著高于假手术组的(0.033 2±0.004 3)和(0.031 7±0.004 6)(P<0.01).多奈哌齐治疗组小鼠在术后4周和8周时学习记忆能力较模型组显著改善(P<0.01),海马CA1区Calpain 1表达各为(0.052 0±0.008 4)和(0.068 0±0.008 4),显著低于模型组小鼠(P<0.05).结论 Calpain 1可能参与了脑缺血再灌注后小鼠VaD的发生,盐酸多奈哌齐改善VaD小鼠学习和记忆的能力可能与其减少Calpain 1表达有关.     

盐酸多奈哌齐对血管性痴呆模型大鼠大脑NO及iNOS的影响

目的：观察盐酸多奈哌齐（DP）对血管性痴呆模型大鼠iNOS表达的影响,探讨其抗血管性痴呆的作用及机制。方法将SD大鼠随机分为假手术组、实验对照组、DP治疗组,每组大鼠20只,采用双侧颈总动脉结扎法制作血管性痴呆大鼠模型。DP干预治疗后,用“Y”型迷宫检测大鼠学习记忆能力,比色法检测大鼠大脑NO及NOS的表达。结果与实验对照组比较,DP治疗后VD大鼠学习记忆能力明显提高,海马iNOS表达明显减少（P＜0.01）。结论盐酸多奈哌齐可改善学习记忆能力,其机制可能是通过下调iNOS的过度表达,减少NO的生成,抑制神经细胞损伤。     

重复经颅磁刺激对血管性痴呆大鼠海马CA1区BDNF、NMDAR1、SYN表达及超微结构的影响

目的研究重复经颅磁刺激(repetitive transcranial magnetic stimulation,rTMS)对血管性痴呆大鼠海马CA1区脑源性神经营养因子(brain derived neurotrophic factor,BDNF)、N-甲基-D-天冬氨酸受体亚单位NR1(N-meth-yl-D-aspartate receptor,NMDAR1)和突触素(synaptophysin,SYN)表达及超微结构的影响,进一步探讨rTMS治疗血管性痴呆的分子机制。方法将36只雄性Wistar大鼠随机分为4组:正常对照组10只、痴呆模型组10只、低频刺激组8只和高频刺激组8只。采用两血管阻断法制备血管性痴呆模型。低频刺激组大鼠接受频率0.5Hz重复经颅磁刺激,高频刺激组大鼠接受频率5Hz重复经颅磁刺激。采用Morris水迷宫测试方法测试各组大鼠空间学习记忆力。应用免疫组织化学方法检测海马CA1区BDNF、NMDAR1、SYN蛋白表达情况,应用透射电镜观察海马CA1区超微结构变化。结果 Morris水迷宫测试结果及透射电镜观察均显示磁刺激组大鼠较痴呆模型组大鼠均有好转。痴呆模型组大鼠BDNF、NMDAR1、SYN蛋白表达量比正常对照组大鼠减低(P0.05),低频刺激组和高频刺激组BDNF、NMDAR1、SYN蛋白表达量均比痴呆模型组增高(P0.05),低频刺激组与高频刺激组之间差异无统计学意义(P0.05)。结论重复经颅磁刺激对血管性痴呆有恢复治疗作用,其机理可能与rTMS能增加大鼠海马CA1区BDNF、NMDAR1和SYN的表达。     

盐酸多奈哌齐对血管性痴呆小鼠海马神经细胞神经元蛋白激酶C表达变化的影响

目的探讨盐酸多奈哌齐对血管性痴呆（Vascular dementia,VD）小鼠海马神经元蛋白激酶C（protein kinase C,PKC）变化的影响。方法将3月龄雄性昆明小鼠随机分为假手术组、模型组、多奈哌齐治疗组。采用双侧颈总动脉结扎,反复缺血-再灌注制备VD模型,药物治疗30d。术后第29、30天,分别进行跳台试验和水迷宫试验观察各组小鼠行为学改变。采用免疫组织化学法观察各组海马CA1区神经元PKC表达的变化。结果药物治疗组小鼠学习、记忆成绩较模型组明显改善（P〈0.05）。模型组PKC免疫反应阳性神经元平均光密度值为（0.2730±0.0709）,与假手术组（0.3206±0.0642）和药物组（0.3036±0.0688）相比均显著降低（P〈0.05）,而药物组与假手术组间无明显差别（P〉0.05）。结论反复缺血-再灌注导致VD小鼠海马神经元PKC表达减少;多奈哌齐通过抑制中枢神经系统中乙酰胆碱的降解,可增加VD小鼠海马神经元PKC表达,从而改善VD小鼠学习、记忆能力,推测此也是该药物改善VD小鼠学习、记忆障碍的一个重要环节。     

Distribution and expression of the subunits of N-methyl-d-aspartate (NMDA) receptors; NR1, NR2A and NR2B in hypoxic newborn piglet brains

The purpose of this study was to identify the distribution and the expression of the NR1, NR2A and NR2B subunits of the NMDA receptor after cerebral hypoxia. Ten piglets were divided into control and hypoxic groups (n=5, each). The control piglets were ventilated with normoxia for 1 h, and the hypoxic piglets were ventilated with hypoxia until p_aO₂ was below 20 mmHg. Tissue samples from the nine different regions of newborn piglet brain were obtained, and the protein amount of the NR1, NR2A, and NR2B subunits measured by immunoblot using the antibody to the NR1, NR2A, and NR2B subunits. The NR1, N2A, and NR2B subunits were distributed very differently; hippocampus and cortical area are more prominent than white matter and cerebellum. But the expression of the NR1, NR2A and NR2B subunits were not significantly different between the control and the hypoxic group, 1 h after hypoxic exposure, indicating no changes in the protein amount of NMDA receptor subunits. These results show a significantly higher amount of the NR1, NR2A and NR2B subunits in the hippocampus and the cerebral cortex of newborn brains, indicating that these structures could be highly vulnerable to excitotoxicity in the newborn brain.     

新生期惊厥对大鼠海马NR1和GABAARα1表达的长期影响

目的 研究新生期惊厥对大鼠海马N-甲基-D-天门冬氨酸(NMDA)受体1(NR1)和γ-氨基丁酸A受体α1亚单位(GABAARα1)表达的长期影响,以期揭示发育期惊厥导致成年大鼠惊厥阈降低的机制.方法 生后6 d的Wistar大鼠48只采用完全随机法分成三氟乙醚吸入惊厥组和对照组,每组各24只,惊厥组再细分为单次惊厥组(诱导惊厥一次,持续30 min)和反复惊厥组(每天诱导惊厥一次,持续30 min,连续6 d),对照组同样操作但不吸入三氟乙醚.分别于惊厥后第7天和第75天取大鼠海马,匀浆提取膜蛋白,应用免疫印记法测定NR1、GABAARα1蛋白表达.结果 单次惊厥组和反复惊厥组75 d的海马NR1表达无显著变化,而反复惊厥组7 d的海马NR1表达较对照组显著增加(P＜0.05).同时,与对照组相比,GABAARα1亚单位在单次惊厥组第75天以及反复惊厥组的表达均有统计学意义(P＜0.05).结论 新生期大鼠反复或单次长程惊厥持续状态能够对海马NR1和GABAARα1表达产生远期影响,这种改变可能在发育期惊厥导致的脑兴奋性提高和惊厥阈降低中起重要作用.     

大鼠大脑皮层损伤后N-甲基D-天门冬氨酸受体亚单位NR1、NR2A和NR2B的表达研究

目的 分析研究急性损伤后大鼠大脑皮层N-甲基D-天门冬氨酸受体(NMDA)亚单位NR1，NR2A和NR2B的表达。方法 建立开放式挫伤型机械脑损伤大鼠模型，采用NMDA受体的NR1，NR2A和NR2B3种亚单位的特异性抗体，对不同时间点的皮层组织3种亚单位蛋白作定量免疫印迹分析。结果 以健侧大脑皮层作为对照组，NR1亚单位在各时间点的含量保持基本稳定。NR2A的含量在3h内升高明显，至3h达到高峰，随后降至正常；NR2B在1h时略有上升后随即下降，至3h时最低，尔后又明显升高，于6h时达高峰，随后又恢复正常。结论 大鼠脑皮层损伤NMDA受体NR2A和NR2B亚单位的表达发生了改变。     

Long-term potentiation in the nucleus accumbens requires both NR2A- and NR2B-containing N-methyl-D-aspartate receptors

N-methyl-d-aspartate (NMDA) receptors play crucial roles in several forms of long-term changes in the efficacy of glutamatergic synaptic transmission. The suggestion that the NR2A subunit of the NMDA receptor may be selectively involved in the induction of long-term potentiation (LTP) in the hippocampus and cortex has been challenged. However, the contribution of NR2B in the induction of LTP is not always clearly established. The present study investigates the role of NR2A and NR2B in the induction of LTP in the nucleus accumbens (NAc), a brain region that expresses high levels of NR2B and an NMDA-dependent form of LTP. We recorded extracellular field excitatory postsynaptic potentials/population spikes in slices of mouse NAc. High-frequency stimulation of glutamatergic fibers consistently induced LTP of the field excitatory postsynaptic potential/population spike in the NAc. LTP was abolished in the presence of selective antagonists of either NR2B [R-(R*,S*)-alpha-(4-hydroxyphenyl)-beta-methyl-4-(phenyl-methyl)-1-piperidine propanol and Ifenprodil] or NR2A ([(R)-[(S)-1-(4-bromo-phenyl)-ethylamino]-(2,3-dioxo-1,2,3,4-tetrahydroquinoxalin-5-yl)-methyl]-phosphonic acid) subunits. Recordings performed in a low concentration of Mg(2+) ions in the perfusion solution did not reveal a selective involvement of a particular NMDA receptor subunit because either NR2A or NR2B antagonists were able to block LTP. LTP was also abolished in the presence of a low concentration of the non-subunit-selective NMDA receptor antagonist dl-2-amino-5-phosphonopentanoic acid in normal Mg(2+) and low Mg(2+) in the perfusion solution. These results show that the degree of NMDA receptor activation, and not their subunit composition, determines whether LTP is induced in the NAc.     

Postnatal development of NR1, NR2A and NR2B immunoreactivity in the visual cortex of the rat

N-Methyl-D-aspartate receptors (NMDARs) are critically involved in some types of synaptic plasticity. The NMDAR subunits NR1, NR2A and NR2B are developmentally regulated, and it has been proposed that developmental changes in their expression may underlie developmental changes in cortical plasticity. Age-dependent change in cortical plasticity is most commonly measured by the monocular deprivation effect, which occurs during a critical period between P22 and P50 in the rat. Although the development of NMDAR subunits has been studied from birth through the fourth postnatal week, there is only meager information from older ages when visual plasticity ends. We hypothesized that there will be significant age-dependent change in expression of NR1, NR2A or NR2B between P22, when the cortex is plastic, and P90, when it is not. We applied specific antibodies recognizing NR1, NR2A and NR2B to the primary visual cortex at P14, P22, P30, P45 and P90. We found age-dependent changes in NR1-IR that were negatively correlated with changes in NR2A-IR; these subunits are not regulated in unison. In contrast, NR2A-IR and NR2B-IR were positively correlated. NR2A-IR and NR2B-IR both passed through a developmental minimum around P45, then recovered to approximately their P22 level. NR1-IR passed through a maximum at P45. There were no significant differences between P22 and P90. These results do not support the simple hypothesis that the loss of plasticity corresponds to a simple transition from juvenile levels of NMDAR subunit proteins to new adult levels. On the other hand, the results do confirm the hypothesis that there are significant changes in processing of NMDAR proteins during the time that plasticity is lost. How these changes of IR relate to synaptic transmission and plasticity needs to be clarified.