多巴胺激动剂阿朴吗啡对东莨菪碱诱导小鼠学习记忆障碍的影响

目的：研究多巴胺（DA）对小鼠学习记忆障碍的影响及其机制。方法：实验1采用腹腔注射东莨菪碱0．3mg／kg（SCOP 0．3,n=10）和3．0mg／kg（SCOP3．0）,连续注射60d,在第53天和60天用避暗法测定记忆行为,第60天处死动物后取脑用免疫组化的方法测定TH-ir和Fos-ir的表达。实验2根据实验1结果造小鼠记忆障碍的模型后将小鼠分成4组,1组腹腔注射生理盐水（NS）,其他3组腹腔注射阿朴吗啡0．1mg/kg（APO 0．1）、0．5mg／kg（APO 0．5）和2．0mg／kg（APO 2．0）,每组10只动物,连续30d。在注射阿朴吗啡第23天和30天测定避暗行为。第30天处死动物后取脑用免疫组化的方法测定Fos-ir和TH-ir的表达。结果：避暗法测定记忆发现东莨菪碱抑制小鼠的记忆。第60天,东莨菪碱3．0mg／kg组（SCOP3．0）的潜伏期比NS组显著缩短,仅是NS组的1／4（P〉0．05）,错误次数比Ns组增加了大约4倍（P〉0．05）,SCOP 0．3组的潜伏期和错误次数与NS组没有明显差异。免疫组化结果表明在伏隔核和海马区的CAl和CA3的Fos-ir细胞数明显降低（P〈0．01）,且被盖腹侧区的酪氨酸羟化酶（TH-ir）和共表达TH／Fos-ir细胞显著减少（P〈0．01）。注射阿朴吗啡后明显缓解了小鼠的记忆障碍,且腹侧被盖区TH-ir细胞增加（P〈0．05）。结论：阿朴吗啡明显减轻东莨菪碱诱导的小鼠记忆障碍,是通过增强腹侧被盖区多巴胺神经元的活性来实现的。     

马齿苋总黄酮对Aβ_(25-35)阿尔茨海默症小鼠学习记忆功能的影响

本实验通过观察马齿苋总黄酮(POTF)对β-淀粉样蛋白(Aβ25-35)所致阿兹海默症(AD)模型小鼠学习记忆的影响,探讨马齿苋总黄酮对AD的改善作用。60只小鼠随机分组,采用海马组织注射Aβ25-35构建AD小鼠模型,经马齿苋总黄酮灌胃治疗30 d后,检测小鼠空间学习记忆能力、海马组织中乙酰胆碱(ACh)和乙酰胆碱酯酶(Ach E)活性、环磷腺苷效应元件结合蛋白(CREB)mRNA和蛋白的相对表达。结果显示,与模型组相比,POTF高剂量组小鼠空间学习记忆能力显著增加(P0.01),海马组织ACh、Ach E和CREB蛋白的表达均明显上升(P0.05)。因此,马齿苋总黄酮(POTF)可能通过增强海马组织胆碱能的代谢,增强CREB信号通路,改善Aβ25-35所致AD小鼠学习记忆能力。     

昆明小鼠学习记忆能力的年龄效应及其与海马突触囊泡蛋白的相关性

为了探讨昆明小鼠(Mus musculus)年龄相关性空间学习记忆能力改变及其与海马突触前囊泡蛋白1(synaptotagmin 1,SytⅠ)含量之间的关系。选取3个年龄段的昆明小鼠,①青年组:6月龄,28只;②中年组:11月龄,22只;③老年组:22月龄,17只。利用六臂辐射状水迷宫(RAWM)任务检测其空间学习记忆能力;制作组织微阵列,采用免疫组化技术检测SytⅠ在海马中的的表达;采用方差分析方法对六臂辐射状水迷宫实验参数和SytⅠ的相对含量进行统计学分析,使用Spearman秩相关检测这二者之间的相关性。结果发现,老年组昆明小鼠在学习期及记忆期的平均错误数及潜伏期均高于中年和青年鼠(P0.05),中年昆明小鼠与青年鼠之间的差异不显著(P0.05);老年组昆明小鼠在海马CA3区及齿状回(dentate gyrus,DG区)中SytⅠ的相对含量显著高于中年鼠和青年鼠(P0.05);昆明小鼠海马CA3、DG区SytⅠ的相对含量与学习期和记忆期的错误数及潜伏期均成正相关(P0.05)。由此推断,昆明小鼠可出现年龄相关性空间学习记忆能力降低,其海马CA3和DG的SytⅠ相对含量出现年龄相关性升高,海马SytⅠ升高可能与昆明小鼠年龄相关性空间学习记忆能力减退有关。     

金思维对东莨菪碱致记忆障碍小鼠脑胆碱能系统的影响

目的 通过建立东莨菪碱记忆障碍模型,采用中药复方金思维进行干预,观察金思维对东莨菪碱致记忆障碍模型小鼠行为学和胆碱能系统的影响,探讨该药的神经保护作用机制。方法 将ICR小鼠随机分为正常对照组;模型组,溶媒0.5%CMC;阳性对照组,多奈哌齐,0.92 mg/(kg·d);金思维大、中、小剂量组,20、10、5 mg/(kg·d)。每组18只,按0.1 mL/10 g小鼠体重连续灌胃给药30 d。末次给药后造模,对照组腹腔注射生理盐水,其余各组腹腔注射东莨菪碱3 mg/(kg·d),溶于0.9%生理盐水,按0.1 mL/10 g小鼠体重注射,进行Morris水迷宫实验。实验结束后取皮层和海马组织,分别测定皮层和海马中乙酰胆碱(Ach)含量、乙酰胆碱酯酶(Ach E)及胆碱乙酰转移酶(Ch AT)活性。结果 金思维可使模型小鼠游泳距离和游泳时间缩短及目标象限停留时间增长;金思维可使模型组小鼠脑内Ach含量升高、Ach E活性下降和Ch AT活性升高。结论 金思维可以改善东莨菪碱导致的记忆障碍模型小鼠学习记忆能力,其机制可能与胆碱能能系统有关。     

戊四氮致痫大鼠情感反应、学习记忆功能及海马N-甲基-D-门冬氨酸受体mRNA表达的改变

目的：探讨实验性癫痫持续状态（SE）对大鼠认知功能的影响及N-甲基-D-门冬氨酸（NMDA）受体表达的变化。方法：戊四氮诱导大鼠SE,采用抬高迷宫和Morris水迷宫观察大鼠情感反应和学习记忆功能的改变。RT-PCR方法检测大鼠海马NMDA受体亚单位NR1mRNA的表达。结果：sE组大鼠在抬高迷宫开放臂中逃避时间延长（P〈0．01）,进入次数增多（P〈0、01）;水迷宫中逃避潜伏期延长（P〈0.01）,搜寻策略变差（P〈0．05）,平台象限游泳时间百分比降低（P〈0．01）,穿越平台次数减少（P〈0．01）。同时伴有海马NR1mRNA表达下调（P〈0．01）。结论：SE可使大鼠情感行为改变和学习记忆功能受损,NR1可能参与这一变化的病理生理过程。     

褪黑素对大鼠空间学习记忆的影响及其机制研究

本研究运用Morris水迷宫和电生理学方法 ,以逃避潜伏期、穿环系数和海马CA1区突触长时程增强(long termpotentiation ,LTP)为指标 ,研究褪黑素对大鼠空间学习记忆能力的影响。实验结果显示 :( 1)在Morris水迷宫 6d训练中 ,对照组大鼠后 4d平均逃避潜伏期为 18 4 4± 2 7s,褪黑素组为 3 0 0 2± 3 6s,两者有显著差异 (P <0 0 1) ;训练 6d后 ,褪黑素组穿环系数为 2 5 68± 2 3 2 % ,明显小于对照组的 4 3 3 3± 2 85 % (P <0 0 1)。( 2 )采用微量注射法给予海马CA1区褪黑素 ,强直后 60min ,fEPSP斜率为基准值的 114 2 8± 1 80 % ,显著低于对照组的 169 71±6 4 8% (P <0 0 1)。( 3 )预先给予东莨菪碱 ,不影响褪黑素对海马CA1区LTP的抑制 ,强直后 60minfEPSP斜率为基准值的 113 70± 5 5 5 %。( 4 )提前给予荷包牡丹碱后给予褪黑素 ,强直后 60minfEPSP斜率为基准值的 162 2 9±10 5 2 % ,明显大于褪黑素组 (P <0 0 1) ,而与对照组无显著差异 (P >0 0 5 )。上述结果表明 ,褪黑素对大鼠的空间学习记忆能力及海马CA1区LTP均有明显的抑制作用 ,两者相关 ;东莨菪碱不能阻断褪黑素对海马CA1区LTP的抑制作用 ,而荷包牡丹碱可以阻断褪黑素对LTP的抑制 ,提示褪黑素的作用可能不是由胆碱能系统所介     

无瓣海桑果实提取物对衰老小鼠学习 记忆能力的影响及其机制研究

无瓣海桑果实为真红树无瓣海桑的果实。研究无瓣海桑果实不同提取物对D-半乳糖所致衰老小鼠学习记忆能力影响及其作用机制。采用Morris水迷宫实验测量无瓣海桑果实不同提取物对小鼠的学习记忆能力影响,HE染色观察各组小鼠脑部神经细胞的变化情况,并测定脑组织超氧化物歧化酶(SOD)活力、谷胱甘肽过氧化物酶(GSH-Px)活力、一氧化氮(NO)含量和单胺氧化酶(MAO)活力。结果表明:与模型组相比,无瓣海桑果实不同提取物处理组小鼠在水迷宫实验中逃避潜伏期明显缩短(P0.05),目标象限停留时间明显增加(P0.05)。无瓣海桑果实不同提取物处理组小鼠脑部神经细胞损伤与模型组相比明显减少,小鼠脑部SOD酶活力和GSH-Px酶活力提高(P0.05),NO含量和MAO活力在脑部显著降低(P0.05)。无瓣海桑果实不同提取物对D-半乳糖致衰老小鼠学习记忆能力有改善作用,无瓣海桑果实不同提取物通过提高小鼠脑内源抗氧化酶(SOD、GSH-Px)活力,降低脑部NO含量和MAO活力来提高D-半乳糖致衰老小鼠的学习记忆能力。     

MPTP致空间学习记忆障碍小鼠脑内NSF表达变化

目的:观察1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)致空间学习记忆障碍小鼠脑内N-乙基马来酰亚胺敏感融合蛋白(NSF)表达变化。方法:C57BL/6J小鼠随机分为2组(n=24),包括对照组和MPTP处理组,雌雄各半。MPTP处理组给予C57BL/6J小鼠MPTP(20 mg/0.2 ml/(kg·d),s.c.)连续8 d,每天一次,对照组给予等量的生理盐水用同样方法处理。第9天起采用水迷宫实验,连续4 d检测C57BL/6J小鼠空间学习记忆的改变,水迷宫实验测试结束后,采用免疫组化和Western blot方法检测小鼠脑内NSF表达改变。结果:每组选取小鼠24只进行水迷宫测试,与对照组相比,MPTP处理组小鼠出现空间学习记忆障碍;每组选取小鼠5只进行免疫组化检测,同时每组选取5只小鼠进行Western blot检测,海马CA1区NSF免疫反应活性明显减弱(P0.01),前额叶皮层NSF的免疫反应活性(P0.01)和蛋白表达(P0.05)都明显增高。结论:MPTP致空间学习记忆障碍小鼠脑内NSF表达出现异常,可能参与MPTP致空间学习记忆障碍的发病机制。     

亚麻木酚素对2型糖尿病小鼠学习记忆的影响及其机制初探

目的:研究亚麻木酚素(Flax ligands,FL)对2型糖尿病模型小鼠空间学习记忆的影响及其初步机制。方法:雄性C57小鼠随机分为对照组(Con)、糖尿病模型组(DM)及亚麻木酚素治疗组(DM+FL),DM与DM+FL组给予高脂饮食加小剂量链脲佐菌素(Streptozotocin,STZ)诱导2型糖尿病模型,之后DM+FL组灌胃给予FL 10 mg/kg,每日一次,连续14天,Con与DM组给予等量生理盐水。通过新物体识别试验、Morris水迷宫试验检测小鼠的学习记忆能力,利用Western blot技术测定小鼠海马脑源性神经营养因子(BDNF)及谷酰胺AMPA受体845位磷酸化(pGluA1-Ser845)蛋白表达水平。结果:与Con组比较,DM组小鼠新物体识别指数显著下降(P<0.01),在Morris水迷宫中逃避潜伏期延长(P<0.05),在目的象限内徘徊时间减少(P<0.01);小鼠海马区BDNF和pGluA1-Ser845的蛋白表达水平均显著低于对照组(P<0.01)。与DM组相比,DM+FL组小鼠新物体识别指数显著提高(P<0.01),在Morris水迷宫中逃避潜伏期明显缩短(P<0.05),目的象限徘徊时间显著增多(P<0.05);小鼠海马区BDNF和pGluA1-Ser845的蛋白表达水平均显著升高(P<0.01)。结论:亚麻木酚素对2型糖尿病小鼠学习记忆有明确改善作用,增加海马BDNF和pGlu-A1-Ser845的表达可能是其潜在作用机制。     

多靶点抗AD bis-MEP-乙二酰胺杂合物ZLA抑制神经元型AChE活性及促智作用研究

目的:探究ZLA对神经元型AChE的抑制活性及其对中枢胆碱能神经功能障碍导致的学习记忆功能减退的改善作用。方法:通过体外实验观察ZLA对神经元型AChE活性的影响;通过ex vivo实验观察ZLA体内AChE抑制活性;利用Morris水迷宫行为学实验探讨ZLA对东莨菪碱诱发的小鼠学习记忆功能障碍的改善作用。结果:ZLA明显抑制人SH-SY5Y神经元细胞和小鼠海马神经元来源的AChE活性。另外,ZLA腹腔注射后以剂量依赖性方式抑制小鼠脑内AChE活性。Morris水迷宫实验结果显示,ZLA显著改善东莨菪碱引起的学习和记忆功能障碍。结论:ZLA能够抑制神经元型AChE活性并具有促智作用。     

Nodakenin, a coumarin compound, ameliorates scopolamine-induced memory disruption in mice

Nodakenin is a coumarin compound initially isolated from the roots of Angelica gigas. In the present study, we investigated the effects of nodakenin on learning and memory impairments induced by scopolamine (1 mg/kg, i.p.) using the passive avoidance test, the Y-maze test, and the Morris water maze test in mice. Nodakenin (10 mg/kg, p.o.) administration significantly reversed scopolamine-induced cognitive impairments in the passive avoidance test and the Y-maze test (P<0.05), and also reduced escape latency during training in the Morris water maze test (P<0.05). Moreover, swimming times and distances within the target zone of the Morris water maze were greater in the nodakenin-treated group than in the scopolamine-treated group (P<0.05). In an in vitro study, nodakenin was found to inhibit acetylcholinesterase activity in a dose-dependent manner (IC(50)=84.7 microM). In addition, nodakenin was also found to inhibit acetylcholinesterase activity for 6 h in an ex-vivo study. These results suggest that nodakenin may be a useful for the treatment of cognitive impairment, and that its beneficial effects are mediated, in part, via the enhancement of cholinergic signaling.     

Z-Guggulsterone Improves the Scopolamine-Induced Memory Impairments Through Enhancement of the BDNF Signal in <Emphasis Type="Italic">C57BL</Emphasis>/<Emphasis Type="Italic">6J</Emphasis> Mice

Memory impairment is a common symptom in patients with neurodegenerative disorders, and its suppression could be beneficial to improve the quality of life of those patients. Z-guggulsterone, a compound extracted from the resin of plant Commiphora whighitii, exhibits numerous pharmacological effects in clinical practice, such as treatment of inflammation, arthritis, obesity and lipid metabolism disorders. However, the role and possible mechanism of Z-guggulsterone on brain-associated memory impairments are largely unknown. This issue was addressed in the present study in a memory impairment model induced by scopolamine, a muscarinic acetylcholine receptor antagonist, using the passive avoidance, Y-maze and Morris water maze tests. Results showed that scopolamine significantly decreased the step-through latency and spontaneous alternation of C57BL/6J mice in passive avoidance and Y-maze test, whereas increased the mean escape latency and decreased the swimming time in target quadrant in Morris water maze test. Pretreatment of mice with Z-guggulsterone at doses of 30 and 60 mg/kg effectively reversed the scopolamine-induced memory impairments. Mechanistic studies revealed that Z-guggulsterone pretreatment reversed the scopolamine-induced increase in acetylcholinesterase (AchE) activity, as well as decreases in brain-derived neurotrophic factor (BDNF) protein expression and cAMP response element-binding protein (CREB), extracellular regulated kinase 1/2 (ERK1/2) and protein kinase B (Akt) phosphorylation levels in the hippocampus and cortex. Inhibition of the BDNF signal, however, blocked the memory-enhancing effect of Z-guggulsterone. Therefore, these findings demonstrate that Z-guggulsterone attenuates the scopolamine-induced memory impairments mainly through activation of the CREB-BDNF signaling pathway, thereby exhibiting memory-improving effects.     

小檗碱对血管性认知功能障碍模型大鼠学习记忆能力的影响*

目的:观察小檗碱(berberine)对血管性认知功能障碍(VCI)大鼠学习记忆的影响。 方法:68只Wistar大鼠随机分为:正常组10只、 假手术组10只、造模组48只。造模组大鼠行双侧颈动脉结扎术制备血管性认知功能障碍模型,造模后大鼠又随机分为血管性认知功能障模型组、小檗碱低剂量(20 mg/kg)组、中剂量(40 mg/kg)组和高剂量(60 mg/kg)组(每组大鼠10只)。治疗组腹腔注射不同剂量的小檗碱,其余组腹腔注射生理盐水,每天1次,共34 d。给药28 d后,Morris水迷宫检测大鼠学习记忆能力;水迷宫实验后,检测超氧化物歧化酶(SOD)活性和谷胱甘肽(GSH)、丙二醛(MDA)以及前脑皮层TNF-α、IL-1β、5-HT的含量与单胺氧化酶(MAO)的含量。 结果:与假手术组比较,模型组大鼠逃避潜伏期显著延长(P＜0.01),通过平台次数显著减少(P＜0.01),海马或前脑皮层SOD、GSH和5-HT水平明显降低(P＜0.01),MDA、TNF-α、IL-1β和MAO水平明显升高(P＜0.01);与模型组相比,小檗碱各治疗组逃避潜伏期显著缩短(P＜0.01,P＜0.05),通过平台的次数显著增加(P＜0.01,P＜0.05),海马或前脑皮层SOD、GSH 和5-HT水平明显升高(P＜0.01),MDA、TNF-α、IL-1β和MAO水平明显降低(P＜0.01)。结论:小檗碱显著提高血管性认知功能障碍模型大鼠的空间学习记忆能力,其机制可能与小檗碱调节大鼠的海马抗氧化应激、抗炎性反应和前脑皮层单胺类神经递质系统的作用有关。小檗碱60 mg/kg组作用较好。     

阿里红多糖通过激活Nrf2/ARE通路改善阿尔茨海默病大鼠海马及脑皮层的氧化应激损伤

探讨阿里红多糖(Fomes officinalis Ames polysaccharides,FOPS)抗氧化应激的作用,并从Nrf2/ARE信号通路研究其作用机制。72只健康雄性SD大鼠称体质量并按随机原则分为空白组、模型组、盐酸多奈哌齐组(0.5 mg/kg)、阿里红多糖高、中、低剂量组(100、50、25 mg/kg),每组12只。采用大鼠双侧海马CA1区注射(5μL/侧)Aβ1-42建立AD大鼠模型,给药30天,Morris水迷宫检测行为学变化,荧光定量RT-qPCR和蛋白免疫印迹法(Western blotting)检测各组大鼠脑皮层和海马组织中结构蛋白Keap1、Nrf2及下游抗氧化蛋白HO-1、NQO1 mRNA及蛋白含量。结果发现,干预30天后,与空白组比较,AD模型组大鼠学习记忆能力显著下降(P<0.01),大鼠海马区及脑皮层Nrf2、NQO1、HO-1的mRNA含量及蛋白表达量显著下降(P<0.01),而Keap1 mRNA含量及蛋白表达量显著升高(P<0.01);与模型组比较,盐酸多奈哌齐和阿里红多糖高、中剂量组大鼠的学习记忆能力显著升高(P<0.01),大鼠海马区及脑皮层Nrf2、NQO1、HO-1 mRNA含量及蛋白表达量显著升高(P<0.05,P<0.01),Keap1 mRNA含量及蛋白表达量显著降低(P<0.05,P<0.01)。研究表明阿里红多糖通过调节Keap1的表达,促进Nrf2激活,诱导NQO1、HO-1的表达,发挥提高机体抗氧化损伤作用,从而改善AD大鼠学习记忆能力。     

Piracetam Prevents Scopolamine-Induced Memory Impairment and Decrease of NTPDase, 5′-Nucleotidase and Adenosine Deaminase Activities

Piracetam improves cognitive function in animals and in human beings, but its mechanism of action is still not completely known. In the present study, we investigated whether enzymes involved in extracellular adenine nucleotide metabolism, adenosine triphosphate diphosphohydrolase (NTPDase), 5′-nucleotidase and adenosine deaminase (ADA) are affected by piracetam in the hippocampus and cerebral cortex of animals subjected to scopolamine-induced memory impairment. Piracetam (0.02 μmol/5 μL, intracerebroventricular, 60 min pre-training) prevented memory impairment induced by scopolamine (1 mg/kg, intraperitoneal, immediately post-training) in the inhibitory avoidance learning and in the object recognition task. Scopolamine reduced the activity of NTPDase in hippocampus (53 % for ATP and 53 % for ADP hydrolysis) and cerebral cortex (28 % for ATP hydrolysis). Scopolamine also decreased the activity of 5′-nucleotidase (43 %) and ADA (91 %) in hippocampus. The same effect was observed in the cerebral cortex for 5′-nucleotidase (38 %) and ADA (68 %) activities. Piracetam fully prevented scopolamine-induced memory impairment and decrease of NTPDase, 5′-nucleotidase and adenosine deaminase activities in synaptosomes from cerebral cortex and hippocampus. In vitro experiments show that piracetam and scopolamine did not alter enzymatic activity in cerebral cortex synaptosomes. Moreover, piracetam prevented scopolamine-induced increase of TBARS levels in hippocampus and cerebral cortex. These results suggest that piracetam-induced improvement of memory is associated with protection against oxidative stress and maintenance of NTPDase, 5′-nucleotidase and ADA activities, and suggest the purinergic system as a putative target of piracetam.     

ESP-102, a standardized combined extract of Angelica gigas, Saururus chinensis and Schizandra chinensis, significantly improved scopolamine-induced memory impairment in mice

We assessed the effects of oral treatments of ESP-102, a standardized combined extract of Angelica gigas, Saururus chinensis and Schizandra chinensis, on learning and memory deficit. The cognition-enhancing effect of ESP-102 was investigated in scopolamine-induced (1 mg/kg body weight, s.c.) amnesic mice with both passive avoidance and Morris water maze performance tests. Acute oral treatment (single administration prior to scopolamine treatment) of mice with ESP-102 (doses in the range of 10 to 100 mg/kg body weight) significantly reduced scopolamine-induced memory deficits in the passive avoidance performance test. Another noteworthy result included the fact that prolonged oral daily treatments of mice with much lower amounts of ESP-102 (1 and 10 mg/kg body weight) for ten days reversed scopolamine-induced memory deficits. In the Morris water maze performance test, both acute and prolonged oral treatments with ESP-102 (single administration of 100 mg/kg body weight or prolonged daily administration of 1 and 10 mg/kg body weight for ten days, respectively, significantly ameliorated scopolamine-induced memory deficits as indicated by the formation of long-term and/or short-term spatial memory. In addition, we investigated the effects of ESP-102 on neurotoxicity induced by amyloid-beta peptide (Abeta25-35) or glutamate in primary cultured cortical neurons of rats. Pretreatment of cultures with ESP-102 (0.001, 0.01 and 0.1 mug/ml) significantly protected neurons from neurotoxicity induced by either glutamate or Abeta25-35. These results suggest that ESP-102 may have some protective characteristics against neuronal cell death and cognitive impairments often observed in Alzheimer's disease, stroke, ischemic injury and other neurodegenerative diseases.     

P7C3 Attenuates the Scopolamine-Induced Memory Impairments in C57BL/6J Mice

Memory impairment is the most common symptom in patients with Alzheimer’s disease. The purpose of this study is to evaluate the memory enhancing effects of P7C3, a recently identified compound with robust proneurogenic and neuroprotective effects, on the cognitive impairment induced by scopolamine, a muscarinic acetylcholine receptor antagonist. Different behavior tests including the Y-maze, Morris water maze, and passive avoidance tests were performed to measure cognitive functions. Scopolamine significantly decreased the spontaneous alternation and step-through latency of C57BL/6J mice in Y-maze test and passive avoidance test, whereas increased the time of mice spent to find the hidden platform in Morris water maze test. Importantly, intraperitoneal administration of P7C3 effectively reversed those Scopolamine-induced cognitive impairments in C57BL/6J mice. Furthermore, P7C3 treatment significantly enhanced the level of brain-derived neurotrophic factor (BDNF) signaling pathway in the cortex and hippocampus, and the usage of selective BDNF signaling inhibitor fully blocked the anti-amnesic effects of P7C3. Therefore, these findings suggest that P7C3 could improve the scopolamine-induced learning and memory impairment possibly through activation of BDNF signaling pathway, thereby exhibiting a cognition-enhancing potential.     

Cognitive enhancing effects of alpha asarone in amnesic mice by influencing cholinergic and antioxidant defense mechanisms

The effect of α-asarone on impairment of cognitive performance caused by amnesic drug scopolamine was investigated. Treatment with α-asarone attenuated scopolamine-induced cognitive deficits as evaluated by passive avoidance and Y-maze test. Administration of α-asarone for 15 d improved memory and cognitive function as indicated by an increase in transfer latency time and spontaneous alternation in passive avoidance and the Y-maze test respectively. To understand the action of α-asarone, the levels of acetylcholinesterase (AChE), malondialdehyde (MDA), and superoxide dismutase (SOD) in the hippocampus (Hippo) and cerebral cortex (CC) of scopolamine-induced amnesic mice were evaluated. The mice treated with Scopolamine showed increased activity of AChE, MDA and SOD levels in both the Hippo and the CC area. Treatment with α-asarone attenuated the increased activity of AChE and normalized the MDA and SOD levels in the Hippo and the CC area in the scopolamine treated amnesic mice. These results suggest that α-asarone has a beneficial effect in cognitive impairment induced by dysfunction of cholinergic system in brain through inhibition of AChE activity and by influencing the antioxidant defense mechanism.     

The effect of 7-oxo-DHEA acetate on memory in young and old C57BL/6 mice

7-Oxo-dehydroepiandrosterone, which can be formed from dehydroepiandrosterone (DHEA) by several mammalian tissues, is more effective than its parent steroid as an inducer of thermogenic enzymes when administered to rats. Using the Morris water maze procedure, we tested DHEA and its 7-oxo-derivative for their ability to reverse the memory abolition induced by scopolamine in young C57BL/6 mice, and for their effect on memory in old mice. A single dose of 7-oxo-DHEA-acetate at 24 mg/kg b.w. completely reversed the impairment caused by 1 mg of scopolamine per kg b.w. (P < 0.001). DHEA (20 mg/kg) was also effective (P < 0.01). In old mice given the same single doses followed by feeding 0.05% of the respective steroid in the diet, memory of the water maze training was retained through a four week test period in mice receiving 7-oxo-DHEA-acetate (P < 0.05) but not in the control or DHEA-treated groups. When old mice were not tested until five weeks after being trained 7-oxo-DHEA exerted a slight, but statistically insignificant, improvement in memory retention. The possible effect of 7-oxo-DHEA in human memory problems deserves investigation.     

Fat-1 expression enhance hippocampal memory in scopolamine-induced amnesia

Omega-3 polyunsaturated fatty acids (PUFA) are critical for optimal brain health and are involved in psychiatric and neurological ailments. Here, we report the effects of higher endogenous omega-3 PUFA on memory impairment in the hippocampus by studying mice with transgenic expression of the fat-1 gene that converts omega-6 to omega-3 PUFA. We performed Y-maze and passive avoidance tests to evaluate the memory function of fat-1 mice treated with scopolamine. Fat-1 mice showed induced alternation in the Y-maze test and increased latency in the passive avoidance test. The effects of scopolamine on hippocampal neurogenesis were confirmed by increases in the number of Ki-67- and DCX-positive cells in the fat-1 mice. Western blotting revealed increased brain-derived neurotrophic factor (BDNF) and phosphorylated cAMP response element-binding protein levels, and lower scopolamine-induced apoptosis based on the cleaved-caspase 3 protein level in fat-1 mice. These findings suggest that higher endogenous omega-3 PUFA prevented granular cell loss, increased BDNF signaling, and decreased apoptosis signaling in scopolamine-treated fat-1 mice. These processes may underlie granular cell survival and suggest potential therapeutic targets for memory impairment.