Aqueous and hydroalcoholic extracts of Black Maca (Lepidium meyenii) improve scopolamine-induced memory impairment in mice.

Lepidium meyenii Walp. (Brassicaceae), known as Maca, is a Peruvian hypocotyl growing exclusively between 4,000 and 4,500 m altitude in the central Peruvian Andes, particularly in Junin plateau. Previously, Black variety of Maca showed to be more beneficial than other varieties of Maca on learning and memory in ovariectomized mice on the water finding test. The present study aimed to test two different doses of aqueous (0.50 and 2.00 g/kg) and hydroalcoholic (0.25 and 1.00 g/kg) extracts of Black Maca administered for 35 days on memory impairment induced by scopolamine (1mg/kg body weight i.p.) in male mice. Memory and learning were evaluated using the water Morris maze and the step-down avoidance test. Brain acetylcholinesterase (AChE) and monoamine oxidase (MAO) activities in brain were also determined. Both extracts of Black Maca significantly ameliorated the scopolamine-induced memory impairment as measured in both the water Morris maze and the step-down avoidance tests. Black Maca extracts inhibited AChE activity, whereas MAO activity was not affected. These results indicate that Black Maca improves scopolamine-induced memory deficits.     

Effect of gamma irradiation on phenol content,antioxidant activity and biological activity of black maca and red maca extracts (Lepidium meyenii walp)

This study was performed to determine the effects of gamma irradiation on UV spectrum on maca, total content of polyphenols, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activities and in vivo biological activities of red and black maca extracts (Lepidium meyenii).

Adult mice of the strain Swiss aged 3 months and weighing 30–35?g in average were used to determine biological activities. Daily sperm production, effect on testosterone-induced prostate hyperplasia and forced swimming test were used to determine the effect of irradiation on biological activities of maca extracts.

Irradiation did not show differences in UV spectrum but improves the amount of total polyphenols in red maca as well as in black maca extracts. In both cases, black maca extract has more content of polyphenols than red maca extract (p?<?0.01). Gamma irradiation significantly increased the antioxidant capacity (p?<?0.05).

No difference was observed in daily sperm production when irradiated and nonirradiated maca extract were administered to mice (p?>?0.05). Black maca extract but not red maca extract has more swimming endurance capacity in the forced swimming test. Irradiation of black maca extract increased the swimming time to exhaustion (p?<?0.05). This is not observed with red maca extract (p?>?0.05). Testosterone enanthate (TE) increased significantly the ventral prostate weight. Administration of red maca extract in animals treated with TE prevented the increase in prostate weight. Irradiation did not modify effect of red maca extract on prostate weight (p?>?0.05).

In conclusion, irradiation does not alter the biological activities of both black maca and red maca extracts. It prevents the presence of microorganisms in the extracts of black or red maca, but the biological activities were maintained.     

Metabolomic differentiation of maca (Lepidium meyenii) accessions cultivated under different conditions using NMR and chemometric analysis

To gain insights on the effects of color type, cultivation history, and growing site on the composition alterations of maca (Lepidium meyenii Walpers) hypocotyls, NMR profiling combined with chemometric analysis was applied to investigate the metabolite variability in different maca accessions. Maca hypocotyls with different colors (yellow, pink, violet, and lead-colored) cultivated at different geographic sites and different areas were examined for differences in metabolite expression. Differentiations of the maca accessions grown under the different cultivation conditions were determined by principle component analyses (PCAs) which were performed on the datasets derived from their 1H NMR spectra. A total of 16 metabolites were identified by NMR analysis, and the changes in metabolite levels in relation to the color types and growing conditions of maca hypocotyls were evaluated using univariate statistical analysis. In addition, the changes of the correlation pattern among the metabolites identified in the maca accessions planted at the two different sites were examined. The results from both multivariate and univariate analysis indicated that the planting site was the major determining factor with regards to metabolite variations in maca hypocotyls, while the color of maca accession seems to be of minor importance in this respect.     

Antioxidant and neuroprotector effect of Lepidium meyenii (maca) methanol leaf extract against 6-hydroxy dopamine (6-OHDA)-induced toxicity in PC12 cells

Reactive oxygen species (ROS) are normally produced during cell metabolism, there is strong evidence to suggest that ROS produced in excess impair the cell and may be etiologically related to various neurodegenerative diseases. This study was undertaken to examine the effects of Lepidium meyenii (MACA) methanol leaf extract on neurotoxicity in PC12 cell exposed to 6-hydroxydopamine (6-OHDA). Fresh samples of “maca” leaves were processed in order to obtain foliar extracts and to evaluate the neurobiological activity on PC12 cells, subjected to the cytotoxic effect of 6-OHDA through the determination of the capacity antioxidant, cell viability and cytotoxicity assays on PC12 cells. The results of the tests of antioxidant activity, showed maximum values of 2262.37 and 1305.36 expressed in Trolox equivalents (TEAC), for the methanolic and aqueous fractions respectively. Cell viability assays at a dose of 10?μg extract showed an increase of 31% and 60% at 6 and 12?h of pretreatment, respectively. Cytotoxicity assays at the same dose and exposure time showed a 31.4% and 47.8% reduction in lactate dehydrogenase (LDH) activity and an increase in superoxide dismutase (SOD) activity. The results allow us to affirm that the methanolic foliar extract of “maca” presents in vitro neurobiological activity of antioxidant protection, increase in cell viability and reduction of cytotoxicity against oxidative stress generated by 6-OHDA. In conclusion, the present study shows a protective role for Lepidium meyenii leaf extract on 6-OHDA-induced toxicity by an antioxidant effect.     

玛咖和西洋参皂苷合用对小鼠免疫功能的影响

目的探讨玛咖(Lepidium meyenii.)干粉与西洋参总皂苷粉合用对小鼠免疫功能的影响.方法90只小鼠进行刀豆素A(ConA)诱导的小鼠淋巴细胞转化实验和NK细胞活性测定;另90只小鼠进行小鼠半数溶血值(HC50)测定和小鼠腹腔巨噬细胞吞噬鸡红细胞实验.实验设6组合用物低、中、高剂量(0.02,0.2和1 g·kg-1·d-1,玛咖根干粉和西洋参总皂苷粉按照质量比937进行均匀混合)组、单一玛咖(0.93 g·kg-1·d-1)组、单一皂苷组(0.07 g·kg-1·d-1)和阴性对照(蒸馏水)组,每组15只.各组每日灌胃一次,每次20 mL·kg,连续30 d后测定各项指标.结果与对照组比较,合用物组显著提高ConA诱导的小鼠淋巴细胞增殖能力,增加HC50值,增强小鼠巨噬细胞对鸡红细胞的吞噬率和吞噬指数,并显著增加NK细胞活性.其作用优于单一玛咖组和单一皂苷组.结论玛咖干粉与西洋参总皂苷粉合用能增强小鼠的免疫功能.     

促智药对樟柳碱所致记忆障碍的改善作用

目的：探讨几种促智药对樟柳碱诱导小鼠记忆障碍模型的影响。方法：动物学习、记忆实验用跳台法和避暗法。结果：几种不同剂量的促智药对樟柳碱所致记忆障碍均有不同程度的改善作用。小鼠跳台和避暗行为潜伏期延长，错误次数减少。结论：康宝和长寿康对樟柳碱所引起的记忆障碍有明显的改善作用，与公认的促智西药尼莫地平、奥拉西坦相似。     

The transillumination technique as a method for the assessment of spermatogenesis using medicinal plants: the effect of extracts of black maca (Lepidium meyenii) and camu camu (Myrciaria dubia) on stages of the spermatogenic cycle in male rats

Abstract

Transillumination technique for assessment of stages of spermatogenic cycle is a useful tool for toxicological studies. This study was designed to determine the effect of two medicinal plants on spermatogenesis in male rats using the transillumination technique. For this, the effect of the combination of a fruit with highest content of ascorbic acid (Myrciaria dubia, camu camu) and extract of black maca (Lepidium meyenii) on seminiferous tubule stages scored by transillumination on intact tubules in adult male rats was assessed. Animals were treated during seven days with vehicle, black maca, camu camu or a mixture of black maca?+?camu camu and assessed for daily sperm production (DSP), stages of spermatogenic cycle as well as antioxidant activity and levels of flavonoids and polyphenols. Black maca increased stages of spermiation (VII–VIII) and mitosis of germ cells (IX–XI), whereas camu camu increased stages of mitosis (IX–XI) and meiosis (XII). Mixture of maca?+?camu camu increased stages of spermiation, mitosis and meiosis. All treatments increased DSP (p?<?0.05) and epididymal sperm count (p?<?0.05). Total polyphenols, flavonoids levels and antioxidant activity were higher in camu camu (p?<?0.001) than in black maca. In conclusion, M. dubia (camu camu) has potential effects improving spermatogenesis and co-administered with maca increase stages of mitosis, meiosis and spermiation of the spermatogenic cycle as assessed by the transillumination technique. This technique is becoming increasingly a useful tool for assessment spermatogenesis.     

Lepidium meyenii (Maca) reversed the lead acetate induced -- damage on reproductive function in male rats.

Rats were treated with 0, 8, 16 and 24 mg/kg of lead acetate (LA) (i.p.) for 35 days with or without Maca. Maca was co-administrated orally from day 18 to day 35. The lengths of stages of the seminiferous epithelium were assessed by transillumination. Also, sex organ weights, testicular and epididymal sperm count, sperm motility, daily sperm production, sperm transit rate and serum testosterone levels were measured. Lead acetate treatment resulted in a dose-response reduction of lengths of stages VIII and IX-XI, and serum testosterone levels. However, rats treated with 8 and 16 mg/kg but not 24 mg/kg of lead acetate showed a low number of testicular spermatids, low daily sperm production (DSP) and low epididymal sperm count. Administration of Maca to rats treated with lead acetate resulted in higher lengths of stages VIII and IX-XI with respect to lead acetate-treated rats. Moreover, treatment with Maca to lead acetate-treated rats resulted in lengths of stages VIII and IX-XI similar to the control group. Maca administration also reduced the deleterious effect on DSP caused by lead acetate treatment. Maca prevented LA-induced spermatogenic disruption in rats and it may become in a potential treatment of male infertility associated with lead exposure.     

越鞠丸对侧脑室注射链脲佐菌素诱导的学习记忆损伤小鼠模型的神经保护作用

目的探讨越鞠丸对侧脑室注射链脲佐菌素(STZ)诱导的记忆损伤小鼠模型的神经保护作用。方法雄性小鼠分为空白对照组、假手术组、STZ模型组、越鞠丸给药组。除空白对照组和假手术组外,所有小鼠侧脑室注射STZ(5 mg/kg),假手术组注射等体积生理盐水,制模后给予越鞠丸[2.0 g/(kg·d)]灌胃6周,每周测定血糖。给药结束后采用Morris水迷宫观察小鼠学习记忆变化,条件恐惧实验检测小鼠恐惧记忆的变化,收集大脑皮层组织,Western blot检测PSD95和Shank3蛋白表达情况。结果与空白对照组比较,侧脑室注射STZ不影响小鼠血糖水平,但是损伤小鼠的学习记忆功能,Morris水迷宫实验中模型组小鼠逃避潜伏期显著延长(P<0.05),条件恐惧实验中小鼠僵直时间百分比下降,恐惧记忆损伤(P<0.05);大脑皮层组织PSD95、Shank3水平降低(P<0.05)。给予越鞠丸后小鼠逃避潜伏期缩短(P<0.05),僵直时间百分比升高,大脑皮层PSD95和Shank3蛋白水平降低缓解(P<0.05)。结论越鞠丸对侧脑室注射STZ引起的认知功能损伤具有保护作用,其机制可能与改善皮层组织PSD95和Shank3蛋白水平降低,从而保护突触功能有关。     

玛咖醇提取物对去卵巢大鼠内分泌激素及血脂水平的影响

目的:研究南美植物玛咖的醇提取物对去卵巢大鼠内分泌激素以及血脂水平的影响.方法:采用双侧卵巢切除术制备去卵巢大鼠模型,造模2周后大鼠灌胃给予玛咖醇提取物,剂量以干粉计分别为1.25和0.5 g·kg-1,qd,连续给药7个月.同时设假手术组、去卵巢模型组(均给予等体积的0.1%聚山梨酯'80)和阳性对照组(给予己烯雌酚0.05 mg·kg-1,隔日一次,连续灌胃7个月).给药3和7个月末测定大鼠血清内分泌激素雌二醇(E2)、睾丸酮(T)和卵泡刺激素(FSH)以及血脂水平.结果:与模型组比较,给药7个月后玛咖醇提取物高、低剂量组的血清FSH均显著降低(P<0.01),低剂量组的大鼠血清E2水平显著升高(P<0.01),但血清T值无显著改变.玛咖醇提取物对血清胆固醇水平具有一定的降低作用,血清三酰甘油在治疗中期呈现上升趋势,而在治疗末期又恢复正常.结论:玛咖醇提取物对去卵巢大鼠内分泌失调具有一定的改善作用.     

大黄酚通过抗氧化应激改善高血氨小鼠学习记忆功能障碍

<正>氨中毒学说在肝性脑病(hepatic encephalopathy,HE)的发生发展中占重要地位。相关研究已明确氨的中枢神经毒性作用[1],包括学习记忆障碍[2]。研究表明,大黄酚具有改善阿尔茨海默病(Alzheimer’s disease,AD)患者的学习记忆和认知功能、提高抗缺氧化能力等多种药理作用[3]。本研究先建立高血氨小鼠模型,通过给予大黄酚,来探讨大黄酚对氨诱导小鼠学习记忆功能障碍的改善作用,报道如下。1材料与方法1.1材料昆明种、健康♂小鼠,体质量25-30 g,由中国医学科学院实验动物中心提供(许可证编号:SCXK京2004     

孕酮和孕烯醇酮硫酸盐对东莨菪碱引起的小鼠记忆损伤的保护作用

目的 :观察孕酮和孕烯醇酮硫酸盐对东莨菪碱引起的小鼠记忆损伤的保护作用。方法 :用东莨菪碱造成小鼠记忆损伤的模型 ,应用被动避暗试验测定潜伏期以评价记忆成绩。结果 :小鼠给予东莨菪碱 (1mg·kg-1,ip)后 ,其潜伏期显著减少 ,表明造成了明显的记忆损伤。孕酮 (1,10mg·kg-1,sc)和孕烯醇酮硫酸盐 (1mg·kg-1,sc)均可以在被动避暗试验中减轻东莨菪碱引起的记忆损伤。结论 :孕酮和孕烯醇酮硫酸盐可改善记忆损伤。     

Maca (Lepidium meyenii) and yacon (Smallanthus sonchifolius) in combination with silymarin as food supplements: in vivo safety assessment.

Yacon and maca are native Andean crops with growing popularity as food supplements often in combination with other components, e.g. silymarin. There are however no published data on their toxicity and safety in humans. The aim of our randomized placebo-controlled 90-day study was to evaluate the effects of yacon and maca in combination with silymarin on plasma and lipoprotein lipids, serum glucose and safety parameters in patients suffering from the metabolic syndrome. No adverse effects were found in volunteers using silymarin (0.8 g/day), silymarin+yacon (0.8+2.4 g/day) and silymarin+maca (0.6+0.2 g/day). A moderate AST level and diastolic blood pressure increase was found in volunteers using maca (0.6 g/day). In conclusion, the combination silymarin+yacon appears to be promising as a nutraceutical in the prevention of diseases with a proatherogenic lipoprotein profile and liver steatosis. The effect of maca on AST level and blood pressure must be considered when using high doses of maca powder. This effect could be reversed by supplementation with silymarin.     

Inhibitory effect of ethanol extract of Magnolia officinalis and 4-O-methylhonokiol on memory impairment and neuronal toxicity induced by beta-amyloid

The components of the herb Magnolia officinalis have exhibited antioxidant and neuroprotective activities. In this study, we investigated effects of ethanol extract of M.officinalis and its major component 4-O-methylhonokiol on memory dysfunction and neuronal cell damages caused by Aβ. Oral pretreatment of ethanol extract of M. officinalis (2.5, 5 and 10 mg/kg) and 4-O-methylhonokiol (1 mg/kg) into drinking water for 5 weeks suppressed the intraventricular treatment of Aβ_1-42 (0.5 μg/mouse, i.c.v.)-induced memory impairments. In addition, 4-O-methylhonokiol prevented the Aβ_1-42-induced apoptotic cell death as well as β-secretase expression. 4-O-methylhonokiol also inhibited H₂O₂ and Aβ_1-42-induced neurotoxicity in cultured neurons as well as PC12 cells by prevention of the reactive oxygen species generation. 4-O-methylhonokiol also directly inhibited β-secretase activity and Aβ fibrilization in vitro. Thus, ethanol extract of M. officinalis may be useful for prevention of the development or progression of AD, and 4-O-methylhonokiol may be a major active component.     

Potentiation of the Ambulation-increasing effect induced by combined administration of MK-801 with ethanol in mice

Although both MK-801 (dizocilpine: 0.1 mg/kg, IP) and ethanol (1.6 nd 2.4 g/kg, PO) only slightly increased ambulatory activity in mice, their combination produced a marked enhancement of the ambulation-increasing effect. The combination of MK-801 (0.03 mg/kg) with ethanol (1.6 and 2.4 g/kg) also elicited a significant increase in the mouse's ambulation. A significant enhancement of the effect was produced by the combination of ketamine (3 and 10 mg/kg) with ethanol only (2.4 g/kg). The ambulation increment induced by the combination of MK-801 (0.1 mg/kg) plus ethanol (1.6 g/kg) was dose-dependently inhibited by YM-09151-2 (0.0001–0.01 mg/kg IP), SCH 23390 (0.001–1 mg/kg IP), reserpine (0.1–1 mg/kg, IP) and ceruletide (0.00001–0.001 mg/kg, IP), and the highest dose of each drug was effective for complete inhibition of the ambulation. Naloxone (0.05–5 mg/kg IP), apomorphine (0.001–0.1 mg/kg IP) and -methyl-p-tyrosine (50–200 mg/kg, IP) partially reduced the ambulatory activity induced by the combination of MK-801 with ethanol. These results suggest that the dopaminergic system, particularly via presynaptic changes in the release of stored dopamine, as well as the opioid system, are involved in the interaction of MK-801 with ethanol.     

A mixture of extracts from Peruvian plants (black maca and yacon) improves sperm count and reduced glycemia in mice with streptozotocin-induced diabetes

Abstract

We investigated the effect of two extracts from Peruvian plants given alone or in a mixture on sperm count and glycemia in streptozotocin-diabetic mice. Normal or diabetic mice were divided in groups receiving vehicle, black maca (Lepidium meyenii), yacon (Smallanthus sonchifolius) or three mixtures of extracts black maca/yacon (90/10, 50/50 and 10/90%). Normal or diabetic mice were treated for 7?d with each extract, mixture or vehicle. Glycemia, daily sperm production (DSP), epididymal and vas deferens sperm counts in mice and polyphenol content, and antioxidant activity in each extract were assessed. Black maca (BM), yacon and the mixture of extracts reduced glucose levels in diabetic mice. Non-diabetic mice treated with BM and yacon showed higher DSP than those treated with vehicle (p?<?0.05). Diabetic mice treated with BM, yacon and the mixture maca/yacon increased DSP, and sperm count in vas deferens and epididymis with respect to non-diabetic and diabetic mice treated with vehicle (p?<?0.05). Yacon has 3.05 times higher polyphenol content than in maca, and this was associated with higher antioxidant activity. The combination of two extracts improved glycemic levels and male reproductive function in diabetic mice. Streptozotocin increased 1.43 times the liver weight that was reversed with the assessed plants extracts. In summary, streptozotocin-induced diabetes resulted in reduction in sperm counts and liver damage. These effects could be reduced with BM, yacon and the BM+yacon mixture.     

Toxicological Aspects of the South American Herbs Cat’s Claw (Uncaria tomentosa) and Maca (Lepidium meyenii)

Recent exceptional growth in human exposure to natural products known to originate from traditional medicine has lead to a resurgence of scientific interest in their biological effects. As a strategy for improvement of the assessment of their pharmacological and toxicological profile, scientific evidence-based approaches are being employed to appropriately evaluate composition, quality, potential medicinal activity and safety of these natural products. Using this approach, we comprehensively reviewed existing scientific evidence for known composition, medicinal uses (past and present), and documented biological effects with emphasis on clinical pharmacology and toxicology of two commonly used medicinal plants from South America with substantial human exposure from historical and current global use: Uncaria tomentosa (common name: cat’s claw, and Spanish: uña de gato), and Lepidium meyenii (common name: maca). Despite the geographic sourcing from remote regions of the tropical Amazon and high altitude Andean mountains, cat’s claw and maca are widely available commercially in industrialised countries. Analytical characterisations of their active constituents have identified a variety of classes of compounds of toxicological, pharmacological and even nutritional interest including oxindole and indole alkaloids, flavonoids, glucosinolates, sterols, polyunsaturated fatty acids, carbolines and other compounds. The oxindole alkaloids from the root bark of cat’s claw are thought to invoke its most widely sought-after medicinal effects as a herbal remedy against inflammation. We find the scientific evidence supporting this claim is not conclusive and although there exists a base of information addressing this medicinal use, it is limited in scope with some evidence accumulated from in vitro studies towards understanding possible mechanisms of action by specific oxindole alkaloids through inhibition of nuclear factor (NF)-κB activation. Although controlled clinical studies have demonstrated reduction in pain associated with cat’s claw intake in patients with various chronic inflammatory disorders, there is insufficient clinical data overall to draw a firm conclusion for its anti-inflammatory effects. An important observation was that experimental results were often dependent upon the nature of the preparation used. It appears that the presence of unknown substances has an important role in the overall effects of cat’s claw extracts is an important factor for consideration. The available animal toxicological studies did not indicate severe toxicity from oral intake of cat’s claw preparations but rather were suggestive of a low potential for acute and subacute oral toxicity, and a lack of evidence to demonstrate genotoxic potential and mutagenic activity. Maca is a clear example of a herb with substantial medicinal use in traditional herbal medicine by indigenous cultures in South America since the first recorded knowledge of it in the seventeenth century. The hypocotyls of maca are the edible part of the plant used for nutritional and proposed fertility-enhancing properties. Maca has been described to possess many other medicinal properties in traditional herbal medicine but only a few of them have been well studied scientifically. Published clinical studies of maca seem to be related to its property as a nutrient, for male fertility and for energy. There are inadequate data regarding the precise mechanism of action of maca. Some studies suggest that secondary metabolites found in maca extracts are important constituents responsible for its physiological effects. Maca has been reported in the scientific literature to have a low degree of acute oral toxicity in animals and low cellular toxicity in vitro. An important finding unveiled by this review is the importance of standardisation in quality and additional basic and clinical research to scientifically validate and understand composition, biological activity, safety and risk. Development of a comprehensive pharmacological and toxicological profile through critical evaluation of existing and future experimental data, especially carefully conducted clinical studies would facilitate the scientific evidence-based approach to understanding potential biological effects of these major traditionally based herbals in current global use.     

毛蕊花苷对高原缺氧小鼠记忆损伤的改善及机制研究

目的 探讨毛蕊花苷对高原缺氧记忆损伤的改善作用及其可能机制。方法 采用八臂迷宫训练小鼠的空间记忆能力,训练成功后随机分为5组：常氧对照组（蒸馏水0.1 ml/10 g）、缺氧模型组（蒸馏水0.1 ml/10 g）、毛蕊花苷低（50 mg/kg）、中（150 mg/kg）、高（300 mg/kg）剂量组,灌胃给药7 d。第4天给药完毕后,除常氧对照组置于饲养室（1 500 m）外,剩余4组置于大型低压氧舱模拟高原缺氧环境（7 500 m,3 d）。行八臂迷宫测试（4 000 m）,解剖取血浆和脑组织,测定脑组织活性氧（ROS）、血浆和脑组织丙二醛（MDA）、还原型谷胱甘肽（GSH）含量,总超氧化物歧化酶（T-SOD）活力。结果 与常氧对照组相比,缺氧模型组八臂迷宫实验各项指标、脑组织ROS、MDA及血浆MDA显著升高,脑组织和血浆GSH含量、T-SOD活力显著降低;与缺氧模型组相比,毛蕊花苷各剂量组八臂迷宫实验各项指标、脑组织ROS、MDA及血浆MDA都呈现不同程度的降低,脑组织和血浆GSH含量、T-SOD活力呈现不同程度的升高。结论 毛蕊花苷对高原缺氧记忆损伤有较好的改善作用,可能与其稳定机体抗氧化酶系统的平衡,减轻氧化应激有关。     

纳洛酮对慢性酒精中毒学习记忆障碍大鼠脑内阿片肽含量的影响

目的：研究慢性酒精中毒对大鼠空间学习记忆的影响、脑区内阿片肽含量的变化，及其阿片受体拮抗剂纳洛酮的治疗作用。方法：3周龄雄性SD大鼠分为4组：给A、B组大鼠自由饮用由含6％逐渐递增至15％（v／v）的乙醇水溶液8周，建立慢性酒精中毒模型，而C、D组自由饮水；8周后B、D大鼠连续10天腹腔注射纳洛酮，A、C组腹腔注射生理盐水；然后用Morris水迷宫训练方法，比较四组大鼠的空间学习记忆能力的差异；采用放射免疫法测定下丘脑、海马、纹状体和前额皮质每克组织中β内啡肽（β-EP：pendorphin）和强啡肽A（DynA：dynophine草药A）的含量。结果：在Morris水迷宫隐匿平台训练中，有多个时段A组动物的逃避潜伏期较正常对照组C长（P〈0．01或P〈0．05），其中纳洛酮治疗后B组比A组明显缩短（P〈0．05）。大鼠慢性酒精摄入后下丘脑、海马和纹状体内的β-EP水平较正常对照组出现不同程度的升高（P〈0．01或P〈0.05或P〈0．001），而海马、纹状体和前额皮质内的DynA水平却出现下降；而给予纳洛酮处理后，能部分或完全逆转脑区内β-EP和DynA含量的变化并改善大鼠学习记忆的行为学成绩（P〈0．05）。结论：酒精损害了大鼠的学习记忆能力，其机制可能与学习相关脑区内的β-EP和DynA水平的变化有关；纳洛酮逆转其部分脑区内阿片肽水平的变化，从而对学习记忆障碍有一定的改善作用。     

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。