人参皂甙对慢性酒精中毒大鼠脑组织内AchE和血清中MAO活性的影响

用50%白酒制作慢性酒精中毒大鼠模型,分别给大鼠以高、中、低剂量的人参皂甙溶液灌胃,测定大鼠脑组织内AchE和血清中MAO的活性,来探讨人参皂甙对大鼠脑组织内AchE和血清中MAO活性的影响,实验结果表明,高剂量人参皂甙能明显抑制慢性酒精中毒大鼠血清中MAO活性,提示人参皂甙对慢性酒精中毒所致的大鼠学习记忆障碍有改善作用。     

中国人参茎叶皂甙对大鼠行为的影响

人参茎叶皂甙５０ｍｇ／ｋｇ灌胃给大白鼠，每天１次，连续７天，于末次给药后１ｈ，采用主动回避反应；被动回避反应；分辨学习等训练方法对受试物进行研究，结果表明人参茎叶皂甙对正常大鼠学习、记忆过程仅有微弱易化作用。通过探索行为研究表明，人参茎叶皂甙明显增加每个训练日大白鼠第１分钟探索活动次数并加速探索活动的适应。对电休克大鼠短期记忆障碍有明显改善作用。     

小鼠暂时性脑缺血引起学习记忆障碍模型的制备及人参皂甙的保…

人参皂甙是人参的主要有效成分。本文在建立小鼠脑缺血再灌注导致学习记忆障碍模型的基础上，用跳台、避暗两种实验方法观察了人参皂甙对小鼠脑缺血再灌注后学习记忆功能的保护作用。结果显示小鼠脑缺血再灌注可以导致学习记忆障碍，而人参皂甙可以对这种记忆障碍起到保护作用。     

人参皂甙Rg1对脑缺血再灌注大鼠脑组织c-Fos蛋白表达的影响

目的:探讨人参皂甙Rg1对脑缺血再灌注大鼠脑组织c-Fos表达的影响。方法:分别给大鼠注射人参皂甙Rg1 10、20、40 mg.kg-1,然后采用大脑中动脉闭塞方法建立脑缺血再灌注模型,应用免疫组化法检测脑组织缺血再灌注24h后c-Fos的表达。结果:与单纯缺血再灌注组相比,人参皂甙Rg1各组c-Fos表达明显降低(P<0.05)。结论:人参皂甙Rg1防治大鼠脑缺血再灌注损伤机制可能与抑制脑组织c-Fos表达有关,且以高剂量效果较好。     

小鼠暂时性脑缺血引起学习记忆障碍模型的制备及人参皂甙的保护作用

人参皂甙是人参的主要有效成分。本文在建立小鼠脑缺血再灌注导致学习记忆障碍模型的基础上，用跳台、避暗两种实验方法观察了人参皂甙对小鼠脑缺血再灌注后学习记忆功能的保护作用。结果显示小鼠脑缺血再灌注可以导致学习记忆障碍，而人参皂甙（１０，１００ｍｇ·ｋｇ－１，ｐｏ）可以对这种记忆障碍起到保护作用。     

枸杞籽油对慢性脑低灌注损伤大鼠的保护作用

目的 观察枸杞籽油对慢性脑低灌注损伤大鼠空间记忆及皮层自由基代谢的影响.方法 SD大鼠50只,随机分为假手术组、模型组及枸杞籽油高、中、低剂量组,除假手术组外,其余各组经双侧颈动脉结扎建立慢性脑低灌注损伤模型,枸杞籽油80、40、20 μL· kg-1灌胃60 d后,进行Morris水迷宫实验,检测其空间记忆能力,水迷宫实验结束后,取大鼠海马及皮层组织测其T-AOC活力及丙二醛(MDA)含量.结果 与假手术组相比,模型组出现明显的学习记忆障碍,治疗组较模型组学习记忆障碍有明显改善.与模型组相比,治疗组脑组织内T-AOC活性显著升高,MDA含量明显降低.结论 枸杞籽油能明显减轻大鼠慢性脑缺血所致认知功能障碍,可能与其清除自由基作用有关.     

人参皂苷Rg1脂质体对东莨菪碱诱导大鼠学习记忆障碍的改善及其作用机制

目的：观察人参皂苷Rg1脂质体（Rg1-L）对东莨菪碱诱导大鼠学习记忆障碍的改善，并探讨其相关机制，方法：制备东莨菪碱诱导大鼠学习记忆障碍模型。采用Y型迷宫评价Rg1-L对模型大鼠学习记忆的影响，并测定大鼠大脑皮质中乙酰胆碱酯酶活性。结果：Rg1-L可以显著改善模型大鼠学习记忆功能。同时抑制大脑皮质中乙酰胆碱酯酶活性。结论：Rg1-L对东莨菪碱诱导大鼠学习记忆障碍模型大鼠的学习记忆功能有显著的改善作用，其机制可能与抑制大脑皮质中乙酰胆碱酯酶活性、提高人参皂苷Rg1生物利用度有关。     

精制原人参二醇皂苷对小鼠学习记忆的影响

目的研究精制原人参二醇皂苷(PDS)对亚硝酸钠、乙醇和东莨菪碱所致小鼠记忆障碍的改善作用。方法 连续给精制PDS组、阳性对照药石杉碱甲组小鼠ig相应药物2周,正常和模型对照组小鼠ig等量生理盐水,末次给药1h后,除空白组sc等量生理盐水外,其余各组均立即sc亚硝酸钠、或乙醇、或东莨菪碱,用被动回避实验观察PDS对小鼠学习记忆功能的影响,并比较精制PDS与粗品PDS、人参皂苷Rb1单体的改善学习记忆的作用。结果精制PDS各剂量均有良好的改善小鼠记忆障碍的作用;与精制PDS相比,同样剂量的粗品PDS和人参皂苷Rb1单体则均未显示改善记忆的作用。结论精制PDS是极有前途的益智药物或保健产品的原料。     

肺咳宁密炼膏治疗慢性支气管炎实验研究

目的:观察肺咳宁密炼膏对慢性支气管炎大鼠的作用,为临床应用提供药理学依据.方法:采用二甲苯致小鼠耳廓肿胀实验、小鼠腹腔毛细血管通透性实验,观察肺咳宁密炼膏抗炎作用;采用烟熏法建立大鼠慢性支气管炎模型,光镜下观察各组支气管与肺组织病理学改变,并检测各组动物血清和肺组织中超氧化物歧化酶(SOD)、丙二醛(MDA)、一氧化氮(NO)含量.结果:与模型组比较,肺咳宁密炼膏高、中剂量组能明显减轻小鼠的耳廓肿胀度,降低小鼠腹腔的毛细血管通透性;高、中剂量组能明显改善慢性支气管炎大鼠肺部病理改变,大鼠血清中,高、中、低剂量组明显升高NO含量,高、中剂量组明显降低MDA含量,高剂量组明显增加SOD活性;大鼠肺组织中,高、中剂量组明显降低MDA含量,高剂量组明显增加NO含量,中剂量组明显增加SOD活性.结论:肺咳宁密炼膏对大鼠慢性支气管炎具有较好的治疗作用,其机制可能与抗氧化和升高NO含量有关.     

大鼠海马内注射β-AP25-35后c-fos在脑内的变化及蜕皮甾酮的影响

目的观察大鼠海马内注射β-AP_25-35后学习记忆行为、c-fos基因表达变化及蜕皮甾酮的干预作用,以探讨蜕皮甾酮改善学习记忆的机制。方法大鼠双侧海马内微注射β-AP_25-35 10 μg,Morris water maze观察其学习记忆行为,免疫组化SABC法观察c-fos基因的表达。结果结果显示,与模型组比较,尼莫地平组及蜕皮甾酮(ECR)组的潜伏期缩短、搜索时间延长;同时模型组大鼠皮层及海马内c-fos蛋白表达明显降低,而高剂量ECR组c-fos蛋白的表达则相对增加。结论海马内注射β-AP_25-35可引起大鼠空间学习记忆障碍,并抑制c-fos的表达;ECR酮可改善β-AP引起的大鼠空间学习记忆障碍,并相对增加c-fos的表达。     

Agmatine, a metabolite of L-arginine, reverses scopolamine-induced learning and memory impairment in rats

Agmatine (l-amino-4-guanidino-butane), a metabolite of L-arginine through the action of arginine decarboxylase, is a novel neurotransmitter. In the present study, effects of agmatine on cognitive functions have been evaluated by using one trial step-down passive avoidance and three panel runway task. Agmatine (20, 40, 80 mg/kg i.p.) was administered either in the presence or absence of a cholinergic antagonist, scopolamine (1 mg/kg i.p.). Scopolamine significantly impaired learning and memory in both passive avoidance and three panel runway test. Agmatine did not affect emotional learning, working and reference memory but significantly improved scopolamine-induced impairment of learning and memory in a dose dependent manner. Our results indicate that agmatine, as an endogenous substance, may have an important role in modulation of learning and memory functions.     

The effects of dieldrin and chlordimeform on learning and memory in the cockroach, Periplaneta americana: a study in behavioral toxicology

A one-session T-maze training procedure for cockroaches in which animals were trained to turn right or left to avoid a shock was utilized to investigate the effects of dieldrin and chlordimeform (two neurotoxic pesticides) on learning and memory. These animals were trained and then tested for retention 5 h later. Three behavioral measures were recorded: choice behavior or direction turned, the time taken to proceed down the runway (runway time), and the time taken to proceed from the runway to either choice arm (choice point time). In control animals the number of correct choices, the runway time, and the choice point time increased with succeeding trials during training. Furthermore, control animals showed retention of correct choice behavior from training to testing. A nontoxic dose (no overt behavioral signs) of dieldrin was injected 2 h before training or 15 min after training. Pretraining injections of dieldrin eliminated correct-choice learning but did not alter the increase with training in runway or choice point times. Posttraining dieldrin administration did not interfere with retention of correct-choice behavior upon testing. These findings indicate that dieldrin induces behavioral alterations in a low acute dose and that detrimental effects are more likely with more complex behavior. Furthermore, behavioral disruption is more likely the closer exposure is to the initial learning of a task. Nontoxic doses of chlordimeform injected 1 h before training eliminated correct-choice learning and facilitated an increase in runway times during training.     

Effects of prenatal exposure to alcohol on activity, anxiety, motor coordination, and memory in young adult Wistar rats

The objective of the present study was to examine the effects of prenatal exposure to ethanol on motor performance, emotionality, learning and memory in young-adult, male Wistar rats. Alcohol was delivered to the pregnant dams intragastrically, throughout gestation days (GD) 7-20, at the dose of 6 g/kg/day resulting in the peak blood alcohol concentration (BAC) of 350 mg/dl as assessed on GD 20. Isocaloric intubation and untreated control groups were included. Alcohol exposed rats were not impaired in the rotarod/accelerod tests. Their behavior in the open field and plus maze suggested increased neophobia. Hyperactivity was not observed. In the spatial-navigation task in the water maze, by the middle of the training, fetal alcohol rats showed a tendency towards a slower place acquisition compared to controls, but statistical analysis of the data did not yield between-group differences significant. Towards the end of the training, all rats reached a similar performance level. No detectable between-group differences were noted either in memory retention after a delay, in reversal learning, or in working memory task. Our findings demonstrate that the adverse behavioral effects of a binge-like alcohol administration during half of the first and throughout the second trimester equivalent are difficult to be disclosed in young-adult male Wistar rats. The possible reasons of the lack of significant behavioral deficits in the fetal-alcohol rats observed in the present study are discussed.     

Post-conditioning propranolol disrupts cocaine sensitization

The aim of this study was to compare the effects of both neuronal NOS (nNOS) and inducible NOS (iNOS) inhibitor 2-iminobiotin, with the more selective nNOS inhibitor N^ω-propyl-L-arginine (NPLA) and selective inducible NOS (iNOS) inhibitor aminoguanidine, on emotional learning, working memory and reference memory, by using three panel runway and passive avoidance paradigm in order to clarify the role of distinct isoforms of NOS in the regulation of learning and memory functions. NPLA and 2-iminobiotin significantly increased the number of errors and latency of working and reference memory performances of rats in three panel runway paradigm and impairs retention for the passive avoidance task. However, aminoguanidine did not affect cognitive functions in three panel runway and passive avoidance test. The effect of NPLA and 2-iminobiotin was reversed by pretreatment with a NOS substrate L-arginine. In conclusion, NPLA and 2-iminobiotin impaired cognitive functions in different kind of tasks used in this study and the effect of NPLA and 2-iminobiotin was found to be NO-dependent. Our results may confirm that nNOS plays the key role on emotional learning, working memory and reference memory in rats.     

Effects of repeated doses of fluvoxamine,mianserin and placebo on memory and measures of sedation

The effects on memory and learning of fluvoxamine 50 mg twice a day were compared with those of mianserin 20 mg twice a day and placebo, each given for 8 days in a double-blind cross-over design to nine healthy human volunteers. At least 1 week was left between the 8-day courses of drugs. Subjects were given a learning task (three trial recall of categorisable word lists) before and 3.5 h after a morning dose on day 1 and before their morning dose on day 8. Delayed recall was assessed on days 1, 4 and 8.Fluvoxamine had no effect on memory performance. Mianserin reduced learning and recall after a single dose but had no effect on day 8 of treatment. The single dose of mianserin had no retrograde effect on memory, affected primacy and middle position items but not recency in the serial position curve, and was seen in reduced inter-trial subjective organisation of recall. Subjects' performance on the first trial of the memory task correlated significantly with their performance on a simple reaction time task, with finger tapping speeds and with their subjective ratings of alertness. It was concluded that the impairments of memory produced by one dose of mianserin are partially by-products of the sedative effects of the drug. Tolerance to both memory impairments and sedative effects built up over the 8-day treatment of mianserin. Offprint requests to: H.V. Curran     

Alcohol and retrograde memory effects: role of individual differences

OBJECTIVE: When alcohol is consumed following learning, the effect on delayed, sober memory can vary from person to person. We examined a range of individual differences to look for predictors of this variability. METHOD: Male social drinkers (N = 65; average age 23.3 years) were exposed to emotionally charged verbal stimulus materials while sober. Participants consumed 1.0 ml/kg alcohol immediately afterward and remained in an environment designed to minimize retrograde interference. Stimulus recall and recognition were tested 24 hours later, when participants had breath-alcohol concentrations of zero. Relationship between memory scores and individual differences (in age, education, alcohol consumption, vocabulary, verbal learning, emotionality, mood state 24 hours after learning, response to alcohol, personality and alcohol expectancies) were determined. RESULTS: Only age and vocabulary were significantly associated with memory score following drinking, probably because they constrained initial understanding of the statements and mediated the effects of alcohol on memory consolidation. CONCLUSIONS: The effects of a given dose of alcohol on emotionally charged verbal memory are similar for men of equal age and verbal skill, but independent of other individual differences. It is most likely that alcohol affects incidental memory by nonspecific enhancement or interference processes.     

人参总皂苷对β-淀粉样肽致小鼠记忆障碍的影响

目的　研究人参总皂苷对 β 淀粉样肽 (β AP)所致学习记忆障碍的影响。方法　给小鼠一次性icv凝聚态 β AP活性片段 (2 5～ 35 ) 3μl (1 0mmol·L-1)造成早老性痴呆动物模型 ,采用避暗试验及Morris水迷宫试验 ,观察人参总皂苷对 β AP(2 5～ 35 )神经毒性的对抗作用。 结果　一次性icv凝聚态 β AP(2 5～ 35 )能导致学习记忆障碍。人参总皂苷(10 0 ,5 0 ,2 5mg·kg-1,ig)可明显改善 β AP(2 5～ 35 )所致被动回避性记忆障碍和空间记忆障碍。结论　人参总皂苷可对抗 β AP(2 5～ 35 )的神经毒性 ,改善 β AP(2 5～ 35 )引起的学习记忆障碍     

Low Doses of 17��-Estradiol and 17��-Estradiol Facilitate, Whereas Higher Doses of Estrone and 17��- and 17��-Estradiol Impair, Contextual Fear Conditioning in Adult Female Rats

Estrogens are known to exert significant structural and functional effects in the hippocampus of adult rodents. In particular, 17β-estradiol can improve, impair, or have no effect on hippocampus-dependent learning and memory depending on dose and time of administration. The effects of other forms of estrogen, such as estrone and 17α-estradiol, on hippocampus-dependent learning have not been as thoroughly investigated. Therefore, the purpose of this study was to investigate the effects of 17β-estradiol, estrone, and 17α-estradiol at three different doses on two different tasks: hippocampus-dependent contextual fear conditioning and hippocampus-independent cued fear conditioning. Adult ovariectomized female rats were injected with one of the estrogens at one of the three doses 30 mins before conditioning to assess the rapid effects of these estrogens on acquisition. Twenty-four hours later memory for the context was examined and 1 h later memory for the cue (tone) was assessed. Levels of synaptophysin were examined in the dorsal hippocampus of rats to identify a potential synaptic correlate of hormonal effects on contextual fear conditioning. Low 17β-estradiol and 17α-estradiol enhanced, whereas high 17β-estradiol and 17α-estradiol impaired, contextual fear conditioning. Only the middle dose of estrone severely impaired contextual fear conditioning. Estrogens did not alter performance in the hippocampus-independent cued task. Synaptophysin expression was increased by estrone (at a middle and high dose) and 17β-estradiol (at a middle dose) in the CA3 region of the hippocampus and was not correlated with cognition. The results of this study indicate that estradiol can positively or negatively influence hippocampus-dependent learning and memory, whereas estrone impairs hippocampus-dependent learning and memory in a dose-dependent manner. These results have important therapeutic implications, as estrone, a main component of a widely used hormone replacement therapy, was shown to have either a negative effect or no effect on learning and memory. It may be possible to use 17α-estradiol and lower doses of estrogens as potential alternatives in hormone replacement therapies.     

Application of a computational decision model to examine acute drug effects on human risk taking

In 3 previous experiments, high doses of alcohol, marijuana, and alprazolam acutely increased risky decision making by adult humans in a 2-choice (risky vs. nonrisky) laboratory task. In this study, a computational modeling analysis known as the expectancy valence model (J. R. Busemeyer & J. C. Stout, 2002) was applied to individual-participant data from these studies, for the highest administered dose of all 3 drugs and corresponding placebo doses, to determine changes in decision-making processes that may be uniquely engendered by each drug. The model includes 3 parameters: responsiveness to rewards and losses (valence or motivation); the rate of updating expectancies about the value of risky alternatives (learning/memory); and the consistency with which trial-by-trial choices match expected outcomes (sensitivity). Parameter estimates revealed 3 key outcomes: Alcohol increased responsiveness to risky rewards and decreased responsiveness to risky losses (motivation) but did not alter expectancy updating (learning/memory); both marijuana and alprazolam produced increases in risk taking that were related to learning/memory but not motivation; and alcohol and marijuana (but not alprazolam) produced more random response patterns that were less consistently related to expected outcomes on the 2 choices. No significant main effects of gender or dose by gender interactions were obtained, but 2 dose by gender interactions approached significance. These outcomes underscore the utility of using a computational modeling approach to deconstruct decision-making processes and thus better understand drug effects on risky decision making in humans.