消瘤平体外诱导人白血病HL-60细胞凋亡及机制研究

目的研究消瘤平对人白血病细胞增殖的抑制及诱导凋亡的作用,揭示其抗白血病的部分作用机制。方法体外常规培养HL-60细胞,以不同浓度的消瘤平作用于细胞,MTT法检测细胞生长抑制率;流式细胞术检测凋亡率和细胞周期;ELISA法检测培养上清液中Caspase-3、Fas和Bcl-2的含量。结果与空白对照组相比,作用24 h后,消瘤平显著抑制HL-60细胞的增殖,且呈时间和剂量依赖性;提高HL-60细胞的凋亡率,并诱导出现G2-M细胞周期阻滞;消瘤平作用48 h后,Caspase-9和Fas蛋白表达量增加,Bcl-2表达减少。结论消瘤平抑制人白血病HL-60细胞的作用机制与阻滞细胞周期于G2-M期和诱导细胞凋亡有关,其诱导凋亡作用可能通过上调Caspase-9、Fas和下调Bcl-2而实现。     

miR-218对新藤黄酸抑制人宫颈癌HeLa细胞增殖作用的影响及机制研究

目的研究miR-218对新藤黄酸抑制人宫颈癌He La细胞增殖作用的影响及其可能的分子机制。方法人宫颈癌He La细胞转染过表达真核表达载体pmiR-218,real-time PCR检测He La细胞miR-218的表达。将He La细胞分为空白对照组、新藤黄酸组、pmiR-218组、质粒对照组、新藤黄酸联合pmiR-218组。MTT法检测各组细胞增殖;流式细胞仪检测各组细胞凋亡;Western blot检测Bcl-2、Bax、E-cadherin表达;real-time PCR检测Bcl-2、Bax和E-cadherin的mRNA表达水平。结果 miR-218真核表达载体pmiR-218转染He La细胞后,细胞内miR-218表达水平明显增加(P<0.05)。miR-218可提高He La细胞对新藤黄酸的敏感性,高表达miR-218能促进新藤黄酸对He La细胞的增殖抑制作用,促进细胞凋亡,下调新藤黄酸对He La细胞Bcl-2/Bax蛋白的表达水平。结论 miR-218可提高He La细胞对新藤黄酸的敏感性,miR-218能增强新藤黄酸对He La细胞增殖抑制作用,并促进He La细胞凋亡,其作用机制可能与下调Bcl-2/Bax的表达有关。     

百里醌抑制大肠癌生长的实验研究

目的:探讨百里醌抑制体内外大肠癌生长的影响及机制。方法:不同浓度百里醌作用人大肠癌细胞株SW480后,CCK-8法检测细胞增殖;流式细胞术检测细胞凋亡;Western blotting检测大肠癌细胞中NF-κB、Bcl-2和Survivin的表达;建立裸鼠大肠癌皮下移植瘤模型,随机分为对照组和实验组(n=10),第3周开始分别经灌胃给予溶媒(1%乙醇)和百里醌(3 mg/只),每周3次,共两周,术后第8周处死裸鼠,测量肿瘤瘤重并计算抑瘤率;免疫组织化学法检测肿瘤组织的NF-κB、Bcl-2和Survivin的表达。结果:与对照组相比,百里醌可显著抑制大肠癌SW480细胞生长,并诱导细胞凋亡;百里醌可明显抑制NF-κB、Bcl-2和Survivin在SW480细胞中表达;与对照组相比较,实验组裸鼠皮下移植瘤生长被显著抑制,肿瘤组织中NF-κB、Bcl-2和Survivin表达下调。结论:百里醌具有抑制体内外大肠癌生长的作用,可能是通过抑制大肠癌中NF-κB及其调控蛋白Bcl-2及Survivin的表达而实现。     

白术内酯Ⅰ对人胃癌细胞SGC-7901裸鼠移植瘤生长及凋亡的影响

目的：研究白术内酯Ⅰ（atractylenolide Ⅰ）对人胃癌细胞SGC-7901裸鼠移植瘤生长及凋亡相关蛋白Bax、cleaved caspase-3、p53、Bcl-2表达的影响。方法：建立SGC-7901裸鼠移植瘤模型,观察白术内酯Ⅰ对肿瘤生长的影响;TUNEL法检测移植瘤组织中的细胞凋亡;Western blotting检测瘤组织中Bax、Bcl-2、cleaved caspase-3及p53蛋白表达。结果：白术内酯Ⅰ不同程度抑制裸鼠SGC-7901移植瘤的生长,与对照组比较,给药后肿瘤体积（TV,tumor volume）、相对肿瘤体积（RTV,relative tumor volume）和相对肿瘤增殖率[T/C（%）,T_RTV/C_RTV]明显下降;移植瘤组织中凋亡细胞明显增多;白术内酯Ⅰ上调移植瘤组织中Bax、cleaved caspase-3及p53的蛋白表达,下调Bcl-2 的蛋白表达。结论：白术内酯Ⅰ能明显抑制人胃癌细胞SGC-7901裸鼠移植瘤的生长,分子机制主要包括增加Bax、cleaved caspase-3、p53蛋白表达,减少Bcl-2蛋白表达,最终导致肿瘤细胞凋亡。     

大黄素对荷人K562细胞裸鼠皮下移植瘤的抑制作用

目的:观察大黄素对白血病K562细胞BALB/c裸鼠皮下移植瘤的抑制作用,检测肿瘤组织中Bax和Bcl-2的表达水平,探讨其作用机制。方法:建立裸鼠K562细胞皮下移植瘤模型,腹腔连续给药12d,处死裸鼠,称取瘤体质量,计算抑瘤率。采用HE染色光镜和透射电镜方法观察肿瘤细胞的凋亡情况,免疫组化方法观察肿瘤组织中Bax和Bcl-2蛋白表达情况,应用RT-PCR检测肿瘤组织中Bax和Bcl-2的mRNA水平。结果:各用药组抑瘤作用与阴性对照组相比差异均具有显著性(P<0.05),高浓度组与羟基脲组具有同等的抑瘤效应(P>0.05),光镜和电镜检测发现大黄素低、中、高浓度组均可见瘤细胞凋亡和坏死,其中以高浓度处理组最为显著,羟基脲处理组部分瘤细胞以坏死为主。免疫组化和RT-PCR结果表明大黄素处理后肿瘤组织中Bax蛋白和Bax mRNA表达上调,Bcl-2蛋白和Bcl-2mRNA表达下调。结论:大黄素可以明显抑制K562细胞在裸鼠体内的生长,其作用机制可能是通过调控肿瘤中Bax及Bcl-2的表达,从而促进细胞凋亡。     

RY10-4对乳腺癌MCF-7裸鼠移植瘤的抑制作用及其机制

目的:探讨2-(1-羟基-4-酮-2,5-环己二烯)-吡喃-4-酮(RY10-4)对乳腺癌裸鼠移植瘤抑制作用及其可能的作用机制。方法:建立乳腺癌(MCF-7)裸鼠移植瘤模型,将造模裸鼠随机分为模型组、RY10-4低剂量组(7.5 mg·kg^-1)、 RY10-4高剂量组(15 mg·kg^-1)和紫杉醇组(15 mg·kg^-1);各组均采取隔天腹腔注射给药,检测各组荷瘤裸鼠移植瘤体积和体质量变化。给药16 d后,处死所有裸鼠,称取各组移植瘤质量,TUNEL法检测凋亡指数,并通过Western blot测定移植瘤中Bcl-2、Bax和MAPK 通路蛋白的表达。结果:与模型组比较,RY10-4低、高治疗组和紫杉醇组瘤体积明显减小,瘤质量明显减轻,抑瘤率分别为29.8%,47.2%,53.8%。TUNEL法结果显示,各治疗组能明显引起移植瘤细胞凋亡(P<0.01)。Western blot结果显示,随着RY10-4治疗量的增加抗凋亡蛋白Bcl-2表达减弱,促凋亡蛋白Bax的表达增强,Bcl-2/Bax值显著下降,与模型组相比差异均有统计学意义(P<0.05);另外,RY10-4治疗组移植瘤细胞中的p-p38和p-ERK表达量明显增加。结论:RY10-4能够抑制乳腺癌移植瘤的生长和诱导乳腺癌细胞的凋亡,其诱导凋亡作用可能与下调Bcl-2蛋白和上调Bax蛋白,降低Bcl-2/Bax值,并激活p38和ERK信号通路有关。     

消瘤1号诱导MCF-7人乳腺癌细胞凋亡的研究

目的:研究中成药消瘤1号诱导MCF-7人乳腺癌细胞的凋亡作用,并通过分析其作用后MCF-7细胞Bax和Bcl-2蛋白表达的变化,探讨其诱导MCF-7细胞凋亡的分子机制。方法:采用细胞培养技术,用1、10、100、1000μg·mL-1的消瘤1号处理MCF-7细胞24h,PI染细胞,流式细胞仪测定细胞周期的变化,Western Blot法检测Bax和Bcl-2蛋白的表达。结果:流式细胞仪检测结果表明细胞阻滞在G0/G1期;Weston Blot法测定结果表明消瘤1号能够增加细胞中Bax蛋白表达,减少Bcl-2蛋白表达,且该2种蛋白的表达依赖于消瘤1号的浓度。结论:消瘤1号可通过调节Bax/Bcl-2蛋白表达的变化诱导MCF-7细胞凋亡。     

苦参碱对人肝癌细胞HepG2荷瘤裸鼠的抑瘤作用研究

目的研究苦参碱对人肝癌细胞HepG2荷瘤裸鼠的抑瘤作用及其作用机制。方法 BALB/C裸鼠随机分为对照组和苦参碱25、50、75 mg/kg组,每组各10只。建立裸鼠肝癌细胞HepG2移植瘤模型。对照组ip生理盐水1 mL,1次/d;苦参碱25、50、75 mg/kg组分别ip 0.5、1.0、1.5 mg/mL苦参碱溶液1 mL,1次/d。连续给药35 d。计算瘤体体积和肿瘤体积抑制率。观察裸鼠瘤体HE染色病理改变和免疫组化染色,测定各组裸鼠瘤体Survivin蛋白表达量,并采用RT-PCR法检测裸鼠瘤体Survivin mRNA相对表达量。结果与对照组比较,苦参碱50、75 mg/kg组裸鼠瘤体体积显著减小(P0.01);苦参碱组裸鼠瘤体生长速度较对照组减慢,肝癌细胞分布较对照组稀疏,且剂量越大越明显。苦参碱50、75 mg/kg组仅有少量Survivin表达于细胞质。与对照组比较,苦参碱50、75 mg/kg组裸鼠Survivin蛋白表达量和Survivin mRNA相对表达量显著减小(P0.01)。结论苦参碱对人肝癌细胞HepG2荷瘤裸鼠具有抑瘤作用,有效剂量为50 mg/kg,其机制可能与下调Survivin表达、诱导肝癌细胞凋亡有关。     

尼美舒利抑制小鼠荷瘤肝癌的生长:提高Bax/Bc 1-2表达的比值(英文)

目的:观察尼美舒利对小鼠荷瘤抑制和凋亡诱导作用并探讨其可能的分子机制。方法:雄性小鼠给予尼美舒利10mg/kg,20mg/kg和40mg/kg各灌胃21天,用电镜,流式细胞术,琼脂糖电泳观察尼美舒利诱导肿瘤细胞凋亡的作用,放射免疫法测定瘤组织PGE_2含量,Western blot观察COX-2,c-myc,Bax和Bcl-2的表达.结果:尼美舒利能抑制小鼠荷瘤生长,且具有剂量依赖性(14％到62％),高剂量时,尼美舒利诱导的细胞凋亡率是(51.3±1.5)％,DNA“梯形”变化更加明显,PGE_2含量明显降低,Westernblot显示COX-2和Bcl-2表达降低,Bax表达增加,c-myc无变化。结论:尼美舒利对荷瘤肝癌的抑制作用可能与抑制COX-2而降低PGE_2含量和上调Bax/Bcl-2比值诱导瘤细胞凋亡有关。     

紫花牡荆素对人宫颈癌裸鼠移植瘤生长的影响及其机制

目的研究紫花牡荆素（CAS）对人宫颈癌HeLa细胞裸鼠移植瘤生长的影响及其机制。方法建立人宫颈癌HeLa细胞裸鼠皮下移植瘤模型,并随机分成5组,每组5只：生理盐水组、顺铂组、低剂量CAS组、中剂量CAS组和高剂量CAS组。观察和比较各组裸鼠移植瘤的体积和重量,裸鼠体重的变化,裸鼠血清乳酸脱氢酶、谷丙转氨酶、肌酐值和外周血白细胞计数的变化;FCM测定瘤组织细胞凋亡率;Westernblot分析瘤组织细胞内p21和cyclinB1的蛋白表达。结果CAS可显著抑制人宫颈癌HeLa细胞裸鼠移植瘤的体积和重量的增加,呈作用剂量和时间依赖性;而对裸鼠的体重、谷丙转氨酶、乳酸脱氢酶、肌酐值和外周血白细胞计数均无明显的影响。CAS作用16天后,裸鼠移植瘤细胞的凋亡率呈剂量依赖性增加,cyclinBl的蛋白表达降低,p21的蛋白表达增高。结论CAS具有抑制人宫颈癌裸鼠移植瘤生长的作用,可能与其降低cyclinB1的蛋白表达,增加p21的蛋白表达,促进细胞凋亡有关。     

Interaction of estrone and estradiol with DNA and protein of liver and kidney in rat and hamster in vivo and in vitro

[6,7-³H] Estrone (E) and [6,7-³H]estradiol-17 (E₂) have been synthesized by reduction of 6-dehydroestrone and 6-dehydroestradiol with tritium gas. Tritiated E and E₂ were administered by oral gavage to female rats and to male and female hamsters on a dose level of about 300 g/kg (54 mCi/kg). After 8 h, the liver was excised from the rats; liver and kidneys were taken from the hamsters. DNA was purified either directly from an organ homogenate or via chromatin. The radioactivity in the DNA was expressed in the units of the Covalent Binding Index, CBI = (mol chemical bound per mol DNA-P)/(mmol chemical administered per kg b.w.). Rat liver DNA isolated via chromatin exhibited the very low values of 0.08 and 0.09 for E and E₂, respectively. The respective figures in hamster liver were 0.08 and 0.11 in females and 0.21 and 0.18 in the males. DNA isolated from the kidney revealed a detectable radioactivity only in the female, with values of 0.03 and 0.05 for E and E₂, respectively. The values for male hamster kidney were < 0.01 for both hormones. The minute radioactivity detectable in the DNA samples does not represent covalent binding to DNA, however, as indicated by two sets of control experiments. (A) Analysis by HPLC of the nucleosides prepared by enzyme digest of liver DNA isolated directly or via chromatin did not reveal any consistent peak which could have been attributed to a nucleoside-steroid adduct. (B) All DNA radioactivity could be due to protein contaminations, because the specific activity of chromatin protein was determined to be more than 3,000 times higher than of DNA. The high affinity of the hormone to protein was also demonstrated by in vitro incubations, where it could be shown that the specific activity of DNA and protein was essentially proportional to the concentration of radiolabelled hormone in the organ homogenate, regardless of whether the animal was treated or whether the hormone was added in vitro to the homogenate.Carcinogens acting by covalent DNA binding can be classified according to potency on the basis of the Covalent Binding Index. Values of 10³–10⁴ have been found for potent, 10² for moderate, and 1–10 for weak carcinogens. Since estrone is moderately carcinogenic for the kidney of the male hamster, a CBI of about 100 would be expected. The actually measured limit of detection of 0.01 places covalent DNA binding among the highly unlikely mechanisms of action. Similar considerations can be made for the liver where any true covalent DNA binding must be below a level of 0.01. It is concluded that an observable tumor induction by estrone or estradiol is unlikely to be due to DNA binding.Paper presented at the Satellite Symposium of the European Society of Toxicology, Rome, March 29, 1983     

Consistency in catecholamine and cortisol excretion in males and females

Data from a series of experiments performed on 24 female and 24 male subjects were used to evaluate the consistency in urinary catecholamine and cortisol excretion. Data were available from 8 laboratory situations of varying activity level and content, spaced at intervals of maximum 3 months. Correlational analyses showed that for cortisol, interindividual consistency was higher for measures obtained on the same day than for measures obtained on different days. Interindividual consistency was generally high in catecholamine and cortisol excretion during non-stressful situations in both sexes. During experimental stress, however, consistency was as high as during nonstress for males, while it was lower for females. Analysis of variance components confirmed these results and showed that in males variation due to interindividual differences was high during both baseline and experimental-stress situations, while in females it was high during baseline situations only. During experimental stress, variation for females was due primarily to interaction. It is suggested that the males showed a more generalized stress response over situations than the females.     

Metabolic interaction between imipramine and carbamazepine in vivo and in vitro in rats

Summary The pharmacokinetic consequences of the combination of carbamazepine with imipramine in male Wistar rats have been investigated. It was found that a 2-week treatment with the combination resulted in the increase of the concentrations of the parent compounds and a simultaneous decrease in their metabolites in blood plasma i.e. carbamazepine inhibited imipramine demethylation in the side chain while imipramine inhibited carbamazepine 10,11-epoxidation. The velocity of imipramine 2-hydroxylation and 10,11-epoxy-carbamazepine hydration did not seem to be changed by the combination. On the basis of studies in vitro it is concluded that the observed metabolic interaction between carbamazepine and imipramine is due to the competition of the drugs for the active centre of cytochrome P 450 and to a certain qualitative alteration of the enzyme by imipramine as can be deducted from the decrease of carbamazepine binding to the cytochrome. Send offprint requests to K. J. Netter     

Nicotine metabolism and urinary elimination in mouse: in vitro and in vivo

This study aimed at elucidating the in vivo metabolism of nicotine both with and without inhibitors of nicotine metabolism. Second, the role of mouse CYP2A5 in nicotine oxidation in vitro was studied as such information is needed to assess whether the mouse is a suitable model for studying chemical inhibitors of the human CYP2A6. The oxidation of nicotine to cotinine was measured and the ability of various inhibitors to modify this reaction was determined. Nicotine and various inhibitors were co-administered to CD2F1 mice, and nicotine and urinary levels of nicotine and four metabolites were determined. In mouse liver microsomes anti-CYP2A5 antibody and known chemical inhibitors of the CYP2A5 enzyme blocked cotinine formation by 85–100%, depending on the pre-treatment of the mice. The amount of trans-3-hydroxycotine was five times higher than cotinine N-oxide, and ten times higher than nicotine N-1-oxide and cotinine. Methoxsalen, an irreversible inhibitor of CYP2A5, significantly reduced the metabolic elimination of nicotine in vivo, but the reversible inhibitors had no effect. It is concluded that the metabolism of nicotine in mouse is very similar to that in man and, therefore, that the mouse is a suitable model for testing novel chemical inhibitors of human CYP2A6.     

Buprenorphine and naloxone alone and in combination in opioid-dependent humans

Subjective, physiological and behavioral effects of subcutaneously administered hydromorphone (6 mg), naloxone (0.2 mg), buprenorphine (0.2 and 0.3 mg), and two buprenorphine-naloxone combinations (buprenorphine 0.2 mg plus naloxone 0.2 mg and buprenorphine 0.3 mg plus naloxone 0.2 mg) were assessed under double-blind conditions in six opioid-dependent volunteers. Physiologic measures and subject- and observer-rated behavioral responses were measured before dosing and for 120 min after drug administration. Hydromorphone decreased pupil diameter and respiration, increased blood pressure and increased scores on subjective measures indicating opioid-like effects. Buprenorphine given alone had no significant effect on any variable measured. Naloxone given alone produced opioid abstinence-like effects which were measurable on subject- and observer-rated behavioral measures and physiological measures. Buprenorphine in combination with naloxone somewhat attenuated the naloxone-precipitated withdrawal response. Overall, the naloxone-buprenorphine combinations produced effects which were qualitatively similar to the effects of naloxone alone, suggesting a low potential for abuse of the combination product by opioid-dependent individuals.Supported by a grant from Reckitt and Colman Pharmaceutical Division and USPHS Grants DA-00050 and DA-04089 from the National Institute on Drug Abuse     

Strain-dependency in motor activity and in concentration and turnover of catecholamines in synchronized rats

Circadian rhythm in motor activity was studied with an Animex motimeter in six strains of rats (ACI, BH, BS, DA, LEW, TNO) synchronized by a 12 hr light: 12 hr dark cycle. ANOVA revealed significant interstrain differences in motor activity as well as in the concentration and turnover of central noradrenaline and dopamine. Strain-dependent differences were also found with regard to tyrosine hydroxylase inhibition on motor activity. However, no significant interstrain correlations were found between endogenous concentration and/or turnover rates of the catecholamines and motor activity in normal and drug-treated rats.     

氯胺酮复合丙泊酚及氯胺酮复合咪达唑仑在小儿麻醉中的麻醉效果对比

目的研究氯胺酮分别复合丙泊酚和咪迟唑仑在小儿麻醉术中及术后的麻醉效果。方法 40例2⁸岁拟在全身麻醉下行择期下腹部手术患儿,不拘性别。随机数字表法分为氯胺酮复合丙泊酚组(A组),氯胺酮复合咪达唑仑组(B组),每组备20例(n=20),比较两组镇痛、镇静效果及躁动、恶心呕吐、呼吸抑制等并发症的发生率。结果两组镇痛及镇静效果均满意,但B组躁动、恶心呕吐的发生率明显高于A组,且A组比B组苏醒时间明显缩短。结论氯胺酮复合丙泊酚用于小儿麻醉效果更加安全圾效。     

Pharmacokinetics and tolerability of artesunate and amodiaquine alone and in combination in healthy volunteers

Objectives  The WHO recommends artemisinin-based combination therapies for treatment of uncomplicated falciparum malaria. At least 15 African countries have adopted artesunate plus amodiaquine as treatment policy. As no pharmacokinetic data on this combination have been published to date, we investigated its pharmacokinetic interactions and tolerability in healthy volunteers in Africa. Methods  In a randomized, three-phase, cross-over study, amodiaquine (10 mg/kg) and artesunate (4 mg/kg) were given as single oral doses to 15 healthy volunteers. Artesunate was given to all volunteers on day 0. On day 7 they received either amodiaquine or amodiaquine plus artesunate and the alternative regimen on day 28. The pharmacokinetics of artesunate and amodiaquine and their main active metabolites dihydroartemisinin and desethylamodiaquine were compared following monotherapy and combination therapy using analysis of variance. Results  Thirteen volunteers completed the study, and pharmacokinetic parameters could be determined for twelve volunteers. When given in combination, the mean AUC was lower for dihydroartemisinin [ratio 67% (95% CI 51–88%); P = 0.008] and desethylamodiaquine [ratio 65% (95% CI 46–90%); P = 0.015] when compared with monotherapy. Adverse events of concern occurred in four volunteers (27%): grade 3 transaminitis (n = 1), neutropaenia (n = 2), and hypersensitivity (n = 1). Conclusion  The total drug exposure to both drugs was reduced significantly when they were given in combination. The clinical significance of these interactions is unclear and must be studied in malaria patients. The frequency and nature of adverse events among the healthy volunteers were of concern, and suggest laboratory monitoring would be needed in malaria patients treated with artesunate plus amodiaquine.     

Evaluation of pharmacokinetic interactions between bicyclol and co-administered drugs in rat and human liver microsomes in vitro and in rats in vivo

1. Bicyclol is a new synthetic anti-hepatitic drug and primarily metabolized by CYP3A. The aim of this study was to evaluate the pharmacokinetic interactions between bicyclol and co-administered drugs including metformin, pioglitazone, atorvastatin, fenofibrate, Cyclosporin A (CsA), and tacrolimus in rat and human liver microsomes (RLMs/HLMs) in vitro and in rats in vivo.

2. The depletion rate of bicyclol in RLMs was significantly inhibited by 44.8% and 35.5% after preincubation with pioglitazone and fenofibrate while the metabolite formation rate of bicyclol in HLMs was inhibited by 26.1% and 23.9% after preincubation and coincubation with tacrolimus, and by 20.2% after preincubation with CsA. Conversely, preincubation and coincubation with bicyclol significantly inhibited the depletion rate of pioglitazone in RLMs by 34.1% and 27.1%, respectively, and the formation rate of para- and ortho-hydroxy atorvastatin in RLMs and HLMs by 20.6–36.2%. There were no significant pharmacokinetic interactions between bicyclol and pioglitazone in rats after a single or multiple oral treatment.

3. As the selected inhibitory drug concentrations in vitro were significantly higher than those in clinical settings and the maximum inhibition rate did not exceed 50%, the clinically significant interaction between bicyclol and these co-administered drugs in humans is predicted less likely to happen.

     

Arsenic induced changes in growth development and apoptosis in neonatal and adult brain cells in vivo and in tissue culture

Arsenic at a nonlethal level in drinking water consumed over a period of time has been reported to produce chronic toxicity and various types of health problems ranging from skin cancer to disturbance in memory. Neurotoxic effects have been reported in clinical cases with chronic exposure to arsenic. Physiological detoxication of arsenic occurs partially through methylation. Arsenic and its methylated derivatives are distributed in different organs and systems. The present study examined the possible interference in the neuronal development and differentiation due to the exposure to arsenic during gestation. The experiments were carried out to examine short and long term effects of arsenic on brain explants and cells grown and maintained in tissue culture system. The effects of arsenic exposure showed changes in brain cell membrane function indicated by generation and release of reactive oxygen-nitrogen intermediates. On the morphological aspect the explants' growth was reduced, ground matrix was lost and neural networking was inhibited. Cells showed signs of apoptotic changes. Arsenic toxicity may induce damage to brain cells prior to more visible clinical conditions. The deleterious effects also pass from the maternal to fetal tissue across the transplacental barrier.