金雀异黄酮通过调控Ca2＋-CaMKIV通路对Aβ25-35诱导海马神经元损伤的保护作用

目的：观察金雀异黄酮通过Ca2＋-钙调蛋白依赖性蛋白激酶IV（calmodulin-dependent protein kinase IV,CaMKIV）通路对Aβ25-35诱导海马神经元损伤的保护作用。方法：取24 h内新生SD乳鼠的海马组织,进行神经元的分离纯化和培养,并用免疫荧光染色进行鉴定。神经元细胞随机分为空白对照组、模型组、金雀异黄酮组（50 μmol/L）和阳性对照戊酸雌二醇组（10 μmol/L）,金雀异黄酮组和戊酸雌二醇组预处理3 h后,除空白对照组外,其他各组采用Aβ25-35诱导海马神经元构建细胞损伤模型。利用噻唑蓝法检测细胞存活率,荧光探针检测神经元细胞内Ca2＋荧光强度,Western blot检测钙调蛋白（calmodulin,CaM）、钙调蛋白依赖性蛋白激酶激酶（calcium/calmodulin dependent protein kinase kinase,CaMKK）、磷酸化钙调蛋白依赖性蛋白激酶IV（p-calmodulin-dependent protein kinase,p-CaMKIV）和p-Tau蛋白的相对表达量。结果：免疫荧光分析结果显示大鼠海马神经元分离成功。与空白对照组比较,模型组海马神经元细胞存活率极显著下降（P＜0.01）,细胞Ca2＋荧光强度极显著升高（P＜0.01）,CaM、CaMKK、p-CaMKIV和p-Tau蛋白相对表达量极显著提高（P＜0.01）;与模型组比较,金雀异黄酮极显著提高了Aβ25-35所致海马神经元损伤模型中细胞的存活率（P＜0.01）,降低了细胞Ca2＋荧光强度（P＜0.01）,下调了CaM、CaMKK、p-CaMKIV和p-Tau蛋白相对表达量（P＜0.01）。结论：金雀异黄酮对Aβ25-35诱导的海马神经元损伤具有明显的神经保护作用,其作用可能是通过Ca2＋-CaMKIV通路介导的。     

Schisandrin enhances dendrite outgrowth and synaptogenesis in primary cultured hippocampal neurons

BACKGROUND: Schisandra chinensis, commonly used in Asia for tea material and traditional Chinese medicine, is presumed to enhance mental and intellectual functions. In this study, the effects and signalling mechanisms of a purified compound schisandrin, one of the lignan of Schisandra chinensis, on primary cultured hippocampal neurons were investigated. RESULTS: Schisandrin treatment enhanced total dendritic length and branching complexity, both of which were significantly suppressed in the presence of specific blockers for calmodulin‐dependent kinase II (CaMKII), protein kinase C epsilon (PKCε), and mitogen activated protein kinase kinase (MEK). Moreover, schisandrin induced calcium influx, and phosphorylation of CaMKII, PKCε, and MEK. Inhibition of CAMKII and PKCε attenuated the schisandrin‐induced phosphorylation of PKCε and MEK, and the phosphorylation of MEK, respectively. Moreover, schisandrin also stimulated the phosphorylation of cyclic AMP responsive‐element binding protein (CREB) at Ser‐133, an effect that was blocked by KN93. In addition to its neuritogenic effects, schisandrin increased the numbers of postsynaptic density‐95‐positive and FM1‐43‐positive puncta in dendrites and synaptic boutons, respectively. CONCLUSION: In hippocampal neurons, schisandrin exhibits neurotrophic properties that are mediated by the CaMKII‐PKCε‐MEK pathway. Copyright © 2010 Society of Chemical Industry     

Augmentation of polysialic acid by valproic acid in early postnatal mouse hippocampus and primary cultured hippocampal neurons

We examined the effects of valproic acid (VPA) on hippocampal neurons. Prenatal VPA exposure significantly increased polysialic acid (PSA) expression in the early postnatal mouse hippocampus. Moreover, VPA treatment significantly enhanced PSA expression in primary cultured hippocampal neurons and stimulated neurite growth. Our results suggest that VPA exposure in ovo affects hippocampal development.     

Trans- and cis-resveratrol increase cytoplasmic calcium levels in A7r5 vascular smooth muscle cells

The effects of trans- and cis-resveratrol on cytosolic Ca2+ concentration ([Ca2+]i) were studied using fura-2 in vascular smooth muscle cells (A7r5). Both isomers of resveratrol caused a sustained elevation in [Ca2+]i, cis-resveratrol being significantly more effective than the trans-isomer. The resveratrol-induced increase in [Ca2+]i was significantly potentiated by the previous application of low concentrations of thapsigargin, partially inhibited by nifedipine or Ni2+, and not affected by SKF 96365. In the absence of extracellular Ca2+, both isomers of resveratrol induced a transient, slow increase in [Ca2+]i, which was inhibited by the previous depletion of intracellular stores with thapsigargin and completely blocked by preincubation with TMB-8, an inhibitor of intracellular calcium release. Reintroduction of Ca2+ in the external solution after the resveratrol-induced release of Ca2+ activated the Ca2+ influx through store-operated calcium channels. The resveratrol-induced increase in [Ca2+]i in the absence of extracelullar Ca2+ partially reduced the increase in [Ca2+]i evoked by the subsequent application of thapsigargin. Our results suggest that trans- and cis-resveratrol induce a depletion of Ca2+ from the same intracellular stores released by thapsigargin and subsequent capacitative influx of Ca2+. Additionally, a direct activation of transmembrane Ca2+ influx through another type of channel may be also implicated.     

白扁豆多糖对神经细胞缺氧性凋亡的保护机制

目的：模拟体内环境,研究白扁豆多糖（dolichos bean seed polysaccharide,DBSP）对胎鼠大脑 皮层神经细胞缺氧性凋亡的保护机制。方法：原代培养胎鼠大脑皮层神经细胞;建立缺氧/复氧（anoxia/ reoxygenation,A/R）损伤模型;实验分4 组：对照组、A/R组、白扁豆多糖预处理组（DBSP＋A/R组）、阻断剂组 （LY294002＋DBSP＋A/R组）;用比色法检测细胞活性与乳酸脱氢酶的释放水平;流式细胞仪分析测定Ca2＋ 相对浓度、活性氧、线粒体膜电位和细胞凋亡的变化;Western blot法检测总蛋白激酶B（total protein kinase B, T-Akt）和磷酸化蛋白激酶B（phosphorylated protein kinase B,p-Akt）蛋白表达。结果：从细胞活性来看,A/R组比 对照组明显降低（P＜0.01）,表明A/R对神经细胞产生了损伤。同时,与A/R组相比,DBSP＋A/R组细胞活性显著 上升、细胞凋亡明显减少（P＜0.01）,乳酸脱氢酶的释放水平下降,表明DBSP对受A/R损伤的神经细胞产生保护 作用,进一步结果显示,与A/R组相比,DBSP＋A/R组中Ca2＋相对浓度和活性氧生成显著降低、显著增加线粒体膜 电位和p-Akt蛋白表达（P＜0.01）。而与DBSP＋A/R组相比,LY294002＋DBSP＋A/R组中p-Akt蛋白表达显著减少 （P＜0.01）,同时细胞活性与线粒体膜电位下降,且LDH的释放水平、Ca2＋相对浓度、活性氧、细胞凋亡明显增加 （P＜0.05）,表明DBSP对神经细胞的保护作用受到PI3K-Akt信号通路抑制剂LY294002的抑制作用而被削弱。结 论：DBSP可通过PI3K-Akt信号转导通路抑制神经细胞的缺氧性凋亡。     

脱味紫薯花色苷色素的稳定性

研究了p H值、金属离子及有机酸对脱味紫薯花色苷色素溶液颜色特征及其稳定性的影响。结果表明,p H 3.0附近时脱味紫薯花色苷色素溶液最稳定;低浓度Fe3+有较强的增色作用,高浓度且随着时间延长Fe3+会导致花色苷降解;Fe2+不仅无增色效果,还会导致脱味紫薯花色苷降解褐变;低浓度的Ca2+、Mn2+和Cu2+对脱味紫薯花色苷色素有一定的辅色作用。草酸、丙二酸和L-苹果酸对紫薯花色苷色素有较好的辅色作用,提高了脱味紫薯花色苷色素的热稳定性,其中草酸辅色最显著,其次是丙二酸和L-苹果酸;柠檬酸和阿魏酸的增色效果不显著,抗坏血酸具有减色作用。     

Perfluorooctane sulphonate (PFOS) throughout the food production chain

Perfluorooctane sulphonate (PFOS) is a persistent organic pollutant with adverse effects on human health. Since dietary intake plays an important role in human exposure, the transfer of PFOS throughout the food chain needs further investigation. The aim of this paper is to give an overview of PFOS concentrations and transfer for the various chain steps from farm-to-fork. This reveals that most research focused on levels of PFOS in surface water and fish but data on soil and crops are largely missing. Furthermore, the uptake of PFOS by farm animals and subsequent transfer into meat and animal products needs further attention, as these products will eventually be consumed by the human population. Once the necessary data gaps are filled, the contribution of the various chain steps on the total PFOS intake can be established. Moreover, the effect of pollution events on the food chain can be established enabling appropriate actions in order to protect consumer health.     

食品接触材料中全氟辛烷磺酸(PFOS)检测方法的研究进展

全氟辛烷磺酸（PFOS）由于具有生物蓄积性、多种毒性和难降解的特点,近年来受到越来越多的国内外学者的关注。作为一种广泛存在的典型全氟化合物,PFOS通过各种途径不同程度地污染了许多日常食物,如快餐包装纸对食物的污染、一次性纸杯对饮料的污染、不粘锅涂层对饭菜的污染等,其中食品接触材料是最易被忽视的一个污染途径。PFOS具有急性毒性、肝脏毒性、神经毒性、免疫毒性、细胞毒性及生殖毒性等多种毒性作用,但在被污染的食品接触材料中,PFOS的含量往往比较低,因此对其快速准确地测定有一定的难度。本文主要综述了PFOS的毒性、PFOS在各种介质中的污染水平、PFOS向食品中的迁移状况以及检测食品接触材料中PFOS的各种方法,并对食品接触材料中PFOS的检测及其发展作出总结与展望。     

Potassium transport at the plasma membrane of the food spoilage yeast Zygosaccharomyces bailii

Zygosaccharomyces bailii is a commercially important spoilage yeast capable of growth at low pH in the presence of weak organic acid preservatives, such as benzoic acid. A patch-clamp electrophysiological analysis of plasma membrane K+ transport revealed a high conductance pathway for low-affinity K+ uptake. In contrast to the equivalent K+ transporter in Saccharomyces cerevisiae, this system remained operative at low extracellular pH and may therefore facilitate K+ uptake in K(+)-rich and acidic beverages. Benzoate inhibited growth, increased intracellular K+ content, yet decreased the magnitude of the K+ uptake conductance; specifically, the hyperpolarization-activated inwardly-rectifying component was reduced. It is proposed that this adaptation helps maintain a hyperpolarized membrane voltage to effect continued ATPase-mediated H+ extrusion and so combat preservative-induced cytosolic acidosis. Again in contrast to S. cerevisiae, the K+ conductance was relatively insensitive to increased extracellular Ca2+. Paradoxically (and unlike S. cerevisiae) increasing extracellular Ca2+ inhibited growth, suggesting a simple expedient to limit spoilage by Z. bailii.     

大麦芽极限糊精酶的分离纯化及酶学特性分析

将大麦芽提取的极限糊精酶粗酶液,利用硫酸铵沉淀、离子交换层析和凝胶过滤色谱等分离方法对极限糊精酶进行逐步分离纯化。结果表明：纯化倍数为31.23,回收率为8.81%。经十二烷基硫酸钠-聚丙烯酰胺凝胶电泳后,图谱显示样品具有较高的纯度,分子质量约为97kD。同时研究了纯化前后极限糊精酶在不同作用环境下酶的活性变化,发现纯化后样品在温度45℃和pH 5.5左右具有最大酶活性,与粗酶液中酶活性相比具有明显差异。在体系中添加不同浓度的金属离子,结果发现,Mg2+、Ca2+、Mn2+在浓度较低时,对酶活性具有激活作用,而浓度较高时,则具有抑制作用;整体上,K+对酶活性影响不大;Zn2+、Fe2+对酶活性具有抑制作用。     

绿色木霉耐高温葡萄糖氧化酶的特性分析

从绿色木霉（Trichoderma viride）WX24菌株发酵中分离、纯化葡萄糖氧化酶（T. viride glucose oxidase,TvGOD）,研究其酶学特性,为葡萄糖氧化酶的应用提供理论基础。将绿色木霉胞外产酶发酵液经硫酸铵沉淀、透析、DEAE-Sepharose Fast Flow阴离子交换层析、Phenyl Sepharose 6 Fast Flow疏水层析和Sephadex G-75分子筛凝胶过滤层析纯化,并研究酶学性质。由十二烷基硫酸钠-聚丙烯酰胺凝胶电泳法测得TvGOD表观分子质量93 kDa,达到电泳纯。经纯化,TvGOD比活力为426.67 U/mg,纯化倍数为14.36,活力回收率19.15%。TvGOD最适pH 6.0,最适反应温度60 ℃。70 ℃以下、pH 4～7之间,TvGOD稳定性好。所测金属离子中,Na＋和K＋对酶活力无影响,Fe2＋、Cu2＋和Zn2＋有轻微抑制作用,Mg2＋和Ca2＋对TvGOD有显著激活作用,而重金属离子Hg2＋和Pb2＋几乎完全抑制酶活力;丝氨酸蛋白酶抑制剂苯甲基磺酰氟和金属螯合剂乙二胺四乙酸二钠对TvGOD抑制作用较为强烈;TvGOD对表面活性剂十二烷基硫酸钠、十六烷基三甲基溴化铵、Triton X-100和吐温80表现出强稳定性。以葡萄糖为底物,酶Km和Vmax分别为11.62 μmol/L和8.244 mmol/（L·min）。基于TvGOD在高温、酸性下的高活性与高稳定性以及对表面活性剂的高耐受性、对底物葡萄糖高亲和性等优良特性,TvGOD很有希望在面粉加工、食品饮料、饲料及生物传感器领域以及需要在高温、高酸环境下使用的生物技术工业中应用。     

大豆皂苷对四氯化碳致肝损伤小鼠肝脏氧化应激的干预作用

研究大豆皂苷对四氯化碳(CCl4)所致急性肝损伤小鼠肝脏氧化应激的干预作用。将实验小鼠按体重随机分为5组,即正常对照组、模型对照组、水飞蓟素组(阳性对照组)及大豆皂苷高、低剂量组。每日给药1次,连续7 d。实验末期,除正常对照组外,其余组小鼠腹腔注射CCl4建立急性肝损伤模型,比色法检测血清白蛋白(Alb)含量、血清谷丙转氨酶(ALT)、谷草转氨酶(AST)、碱性磷酸酶(ALP)活性以及肝脏超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GPx)活性及还原型谷胱甘肽(GSH)、丙二醛(MDA)含量。结果显示,大豆皂苷明显增高CCl4致急性肝损伤小鼠血清Alb水平,降低血清ALT、AST和ALP活性;升高肝组织总SOD、CAT和GPx活性,提高肝GSH水平,降低肝MDA水平;升高肝线粒体Na+-K+-ATPase、Ca2+-Mg2+-ATPase和Mn-SOD活性,降低肝线粒体MDA含量。这说明大豆皂苷可降低CCl4致急性肝损伤小鼠肝脏氧化应激,对肝损伤具有保护作用。     

Effects of reducing dietary cation-anion balance on calcium kinetics in sheep.

A Ca kinetic study with a four-compartment model being fitted to radioisotope and balance data using the CONSAM (conversational, simulation, analysis, and modeling) computer program was conducted to examine the effects of dietary cation-anion balance, calculated as milliequivalents [(Na + K] - (Cl + S)]. Twelve crossbred wethers were used as eucalcemic control (period 1); then Ca loss during lactation was simulated by continuous infusion of ethylene glycol tetraacetate (period 2). Dietary cation-anion balance was manipulated by supplementation of various mineral salts and was +339, +35, and -127 meq of kg DM-1 during period 1 and +429, +68, and -147 meq of kg DM-1 during period 2 for control and two treatments, respectively. Animals responded to the simulated lactational Ca loss (period 2) by increasing true intestinal absorption of Ca and bone resorption and by reducing Ca accretion by bone. No difference was observed in concentration of total Ca in plasma, but treatments produced increased concentration of plasma ionized Ca during both periods. Both treatments produced hypercalciuria during both periods, and the lowest cation-anion balance increased true intestinal absorption of Ca and reduced bone accretion during period 2. The size of total exchangeable Ca pool did not differ between treatments or periods, but amount of Ca movement between the pools increased with the intermediate cation-anion balance during period 1 and with both treatments during period 2 compared with control. These results indicated that feeding reduced cation-anion balance diets increased Ca flux through the exchangeable Ca pool with no changes in the size of the pool, particularly when Ca demand was increased.     

一次性纸杯中全氟辛酸 及全氟辛烷磺酸的膳食暴露研究

为了评估不同人群通过一次性纸杯摄入全氟辛酸(PFOA)及全氟辛烷磺酸(PFOS)的风险,采用超高效液相色谱串联质谱法测定一次性纸杯中PFOA及PFOS向不同食品中的迁移量,结合调查所得一次性纸杯的消费数据,利用点评估方法计算PFOA及PFOS通过一次性纸杯向不同人群的急性及慢性暴露量,并评估其急慢性暴露风险。结果表明,20种一次性纸杯中,PFOA及PFOS向食品中的迁移量分别为ND~23.70×10-3 ng/cm2、ND~4.10×10-3 ng/cm2;PFOA及PFOS的急性人群暴露量分别为45.67×10-3~168.36×10-3 ng/(kg·d)和7.91×10-3~29.14×10-3 ng/(kg·d),慢性人群暴露量分别为0.16×10-3~4.05×10-3 ng/(kg·d)和0.02×10-3~0.51×10-3 ng/(kg·d),均远低于欧盟推荐的每日摄入耐受量。人群通过一次性纸杯摄入PFOA及PFOS的风险处于可接受的水平。     

Double transfection into primary dissociated neurons

Synapses play a fundamental role in the processing of information in a neuronal network by mediating communication between neurons. To monitor presynaptic and postsynaptic structures simultaneously in living neurons, we developed double transfection method on the basis of calcium phosphate coprecipitation and introduced two fluorescent reporters into cultured neurons. The optimized protocol allowed different populations of neurons to be visualized by different color fluorescences, and presynaptic and postsynaptic structures to be observed in the same field of view of a microscope.     

云芝(Coriolus versicolor)木质素过氧化物酶(LiP)酶学性质分析

研究云芝(Coriolus versicolor)产木质素过氧化物酶(Lip)酶活力随时间的变化情况,以及温度、pH 值、金属离子及化合物对云芝LiP 酶活力和稳定性的影响,对该酶底物浓度效应和Km 值进行测定。结果表明：云芝培养12d,其酶活力最高,为72U/mL。该酶的最适温度为40℃,在30～40℃范围内稳定;最适pH 值为2.5,pH 值在2.0～3.5 较稳定;Zn2+ 对LiP 有激活作用,Na+ 对酶活力没有影响,Ca2+、K+、Mg2+、Mn2+、Cu2+ 及EDTA、SDS、β- 巯基乙醇都表现出抑制作用;Km 值为2.05 × 10-4mol/L。     

Gap-junctional communication in mouse cumulus-oocyte complexes: implications for the mechanism of meiotic maturation

The mechanisms underlying the hormonal stimulation of meiotic maturation are not understood. The most prevalent hypothesis is that hormone-induced maturation is stimulated by an increase in the intracellular messengers, cAMP or Ca2+. This study investigated whether Ca2+ transients in somatic cells can lead to Ca2+ transients in the oocyte, and whether hormones that stimulate meiotic maturation of mouse oocytes in vitro and in vivo stimulate an increase in intracellular Ca2+. Of a range of potential agonists of Ca2+ release, ATP and UTP were the only agents that stimulated Ca2+ release in cumulus cells. ATP-induced Ca2+ release is from intracellular stores, as the response is not blocked by chelation of extracellular Ca2+, but is inhibited by the Ca2+-ATPase inhibitor, thapsigargin. ATP and UTP are equipotent, consistent with the receptor being of the P2Y2 type. Confocal microscopy was used to show that ATP-induced Ca2+ release in cumulus cells leads to a Ca2+ increase in the oocyte. Inhibition of gap-junctional communication using carbenoxolone, as assayed by dye transfer, inhibited the diffusion of the Ca2+ signal from the cumulus cells to the oocyte. Thus, provided that a Ca2+ signal is generated in the somatic cells in response to maturation-inducing hormones, it is feasible that a Ca2+ transient is generated in the oocyte. However, FSH and EGF, both of which stimulate maturation in vitro, have no effect on Ca2+ in cumulus--oocyte complexes. Furthermore, LH, which leads to meiotic maturation in vivo, did not stimulate Ca2+ release in acutely isolated granulosa cells from preovulatory mouse follicles. These studies indicate that ATP may play a role in modulating ovarian function and that diffusion of Ca2+ signals through gap junctions may provide a means of communication between the somatic and germ cells of the ovarian follicle. However, our data are not consistent with a role for Ca2+-mediated communication in hormone-mediated induction of meiosis in mice.     

Effects of mineral salts and calcium chelating agents on the gelation of renneted skim milk

The effects of adding CaCl2, orthophosphate, citrate, EDTA, or a mixture of these, to reconstituted skim milk (90 g of solids/kg solution) on the gelation of renneted milk were mediated by changes in Ca2+ activity and the casein micelle. At pH 6.65, the addition of citrate or EDTA, which removed more than 33% of the original colloidal calcium phosphate with the accompanying release of 20% casein from the micelle, completely inhibited gelation. Reformation of the depleted colloidal calcium phosphate and casein in the micelle, by the addition of CaCl2, removed this inhibition. When the minimum requirements for colloidal calcium phosphate and casein in the micelle were met, the coagulation time decreased with increasing Ca2+ activity, leveling off at high Ca2+ activity. The storage modulus of renneted gels, measured at 3 h, increased with increasing colloidal calcium phosphate content of micelles up to a level at which it was approximately 130% of the original colloidal calcium phosphate in the micelles. Further increases in colloidal calcium phosphate by the addition of CaCl2, orthophosphate, or mixtures of these, which did not change the proportion of casein in the micelle, decreased the storage modulus. The gelation of the renneted milk was influenced by Ca2+ activity, the amounts of colloidal calcium phosphate, and casein within the micelle, with the effects of colloidal calcium phosphate and casein within the micelle clearly dominating the storage modulus. These results are consistent with the model of Horne (Int. Dairy J. 8:171-177, 1998) which postulates that, following cleavage of the stabilizing K-casein hairs by rennet, the properties of the rennet gel are determined by the balance between the electrostatic and hydrophobic forces between casein micelles.     

Influence of model melanoidins on calcium-dependent transport mechanisms in smooth muscle tissue

Melanoidins obtained from L-arginine and D-glucose (MW > 3500 Da) were tested for their ability to influence the contractility of gastric smooth muscles. A study within the range 0.1-10 mg/mL revealed that at low concentrations, the melanoidins provoked concentration-dependent contraction, whereas a muscle relaxation was registered at high concentrations. The contraction was preceded by changes in the calcium membrane current as measured by single sucrose-gap method and significantly attenuated by the calcium channel blockers D-600 and nifedipine. Measurements with Ca(2+)-selective electrode showed that the melanoidins decreased the concentration of ionized Ca(2+ )in tissue bath in concentration-dependent manner. Experiments carried out in solutions with lower than normal Ca(2+) concentration and using melanoidins preliminary saturated with Ca(2+ )confirmed that the calcium chelation by melanoidins was a key contributing cause for the development of relaxant response. The results obtained showed that the melanoidins could influence the contractility of smooth muscles through at least two pathways: at low concentrations they caused depolarization and activation of L-type calcium channels, stimulated the Ca(2+ )influx, and provoked contraction, whereas at high concentrations calcium binding by melanoidins led to significant depletion of extracellular calcium ions and contributed to the relaxation process observed.     

Zinc‐containing yeast extract promotes nonrapid eye movement sleep in mice

Zinc is an essential trace element for humans and animals, being located, among other places, in the synaptic vesicles of cortical glutamatergic neurons and hippocampal mossy fibers in the brain. Extracellular zinc has the potential to interact with and modulate many different synaptic targets, including glutamate and GABA receptors. Because of the central role of these neurotransmitters in brain activity, we examined in this study the sleep‐promoting activity of zinc by monitoring locomotor activity and electroencephalogram after its administration to mice. Zinc‐containing yeast extract (40 and 80 mg/kg) dose dependently increased the total amount of nonrapid eye movement sleep and decreased the locomotor activity. However, this preparation did not change the amount of rapid eye movement sleep or show any adverse effects such as rebound of insomnia during a period of 24 h following the induction of sleep; whereas the extracts containing other divalent cations (manganese, iron, and copper) did not decrease the locomotor activity. This is the first evidence that zinc can induce sleep. Our data open the way to new types of food supplements designed to improve sleep.