抗虫灵对大鼠脑组织乙酰胆碱酯酶的抑制作用

有机磷杀虫剂是最常用的杀虫剂之一。抗虫灵是华中师范大学农药研究所研制的新型有机磷杀虫剂,又称９１０５,化学名称为Ｏ－甲基－Ｏ－对甲硫基苯基硫代磷酰胺酯（Ｏ－ｍｅｔｈｙｌ－Ｏ－Ｐ－ｍｅｔｈｉｏｐｈｅｎｙｌｔｈｉｏｐｈｏｓｐｈｏｒａｍｉｄｏｔｓ）,经田间...     

砷对大鼠大脑乙酰胆碱酯酶（AChE）活性的影响

目的：探讨不同剂量砷对大鼠大脑乙酰胆碱酯酶(AChE)活性的影响。方法：以剂量递增法建立染砷大鼠动物模型12周后测定不同剂量砷对大鼠大脑乙酰胆碱酯酶(AChE)活性。结果：乙酰胆碱酯酶(AChE)、各剂量组有显性差别(P＜0．05)随剂量增加AChE活性降低(P＜0．05)。结论：随染砷剂量增加，大鼠大脑AChE活性发生变化。     

猪血红细胞膜提纯乙酰胆碱酯酶

本实验采用亲和层析法提纯猪血红细胞膜乙酰胆碱酯酶,将乙酰胆碱酯酶(EC,3,1,1,7,简称AchE)的可逆性抑制剂(间-羧苯二甲基碘乙基季铵盐)共价连接到Sepharose4B上,用含0.5％Triton X-100的0.01M pH7.2磷酸缓冲液将AchE从猪血红细胞膜上溶解下来,再经亲和层析,比活力提高13(?)0倍,产率40.6％。     

实验性脑缺血再灌注中乙酰胆碱酯酶的研究现状

目前已公认 ,中枢胆碱通路神经系统与学习记忆和认知功能有极其密切的关系。乙酰胆碱是最重要的神经递质之一 ,乙酰胆碱酯酶 (ACh E)是乙酰胆碱 (ACh)的专一水解酶 ,是 ACh正常发挥其生物活性的关键物质之一。在以往的实验性脑缺血再灌注研究中 ,有关 ACh E的论述很多 ,现综述如下。1　脑缺血再灌注后 ACh E活性异常升高方之勇等 [1 ]采用反复夹闭双侧颈总动脉 (CCA)制作血管性痴呆大鼠模型。经检测发现 ,模型组大鼠脑内 A Ch含量明显降低 ,ACh E活性明显升高 ,均有统计学意义。彭国红等 [2 ] 研究发现大鼠脑缺血再灌注 7d可致明显…     

微量电鳐乙酰胆碱酯酶抑制法测定低剂量梭曼浓度

微量电鳐乙酰胆碱酯酶抑制法测定低剂量梭曼浓度刘星，陈起展梭曼是一种能对机体内乙酰胆碱酯酶（ＡＣｈＥ）强烈抑制而产生毒性的有机磷化合物。我们在Ｈａｍ－ｍｏｎｄ［１］等建立的微量ＡＣｈＥ抑制法测定微量有机磷毒剂浓度基础上改进，建立了一种新型的测定方法，其...     

乙酰胆碱酯酶及其抑制剂的研究进展

阿尔茨海默病（Ａｌｚｈｅｉｍｅｒ‘ｓｄｉｅａｓｅ,ＡＤ）为一类比较复杂的认知功能障碍性疾病,是引起老年性痴呆和行为功能异常的主要原因,胆碱能假说为ＡＤ的治疗提供第一个理论,即通过加强胆碱能传递率来预防和治疗,在缓解胆碱能的缺损和改善病人症状方面,乙酰胆碱酯酶的抑制是目前最成功的方法,本文介绍乙酰胆碱酯酶的分子类型,基因结构和作用机理,以及乙酰胆碱酯酶抑制剂的研究进展,其中酶抑制剂可以按结构类型划分     

抗伸展的乙酰胆碱酯酶的单克隆抗体

用还原并烷基化的伸展的电鳐电器官乙酰胆碱酯酶(RA·AChE)为抗原,免疫BALB/c小鼠,经2次基础免疫及3次加强免疫注射后,取脾脏细胞与SP2/0 Ag 14小鼠骨髓瘤细胞,在PEG 1000作用下融合,经克隆筛选,获5个分泌抗RA-AChE单克隆抗体的杂交癌细胞系,细胞培养上清液滴度可达1:10~3,细胞注射同系小鼠制备的腹水抗体,滴度达1:10~5～10~6,表位分析提示5个单克隆抗体分别作用于AChE上的3个抗原决定簇,ELISA测定表明它们与RA-AChE及天然AChE均有较强的抗原抗体反应,但对天然AChE的催化活性无明显抑制作用。     

梭曼4个异构体与乙酰胆碱酯酶相互作用的计算机模拟

采用计算机模拟方法研究了梭曼4个异构体与乙酰胆碱酯酶（AChE）活性中心的作用情况. 结果表明RR构型的梭曼对AChE的作用最强,而在RS, SS和SR构型的梭曼分子中,由于磷原子(P)上的甲基对His440的排斥作用,使其上的咪唑环旋转,削弱了His440促进磷酰化酶的老化作用,同时也得出梭曼上的(CH₃)₃C^＋与Trp84和Phe330残基上的芳香环也有一定的静电相互作用.     

脊椎动物乙酰胆碱酯酶的多糖抗原决定簇及其抑制性单…

抗丁低双鳍电鳐电器官乙酰胆碱酯酶（ＡＣｈＥ）的抑制性单克隆抗体１Ｈ１１（ＩｇＭ），丁氏双鳍电鳐，石纹电鳐电官，比目鱼肌肉，大鼠脑，牛脑，人脑，牛红细胞及人红细胞ＡＣｈＥ均以不同的亲和层析法提纯，用酶抗原免疫测定法及不同的亲和层析法提纯，用酶抗原免疫测定法及酶联免疫吸附测定法检测了１Ｈ１１与上述脊椎动物的ＡＣｈＥ的交叉免疫反应性，结果表明，１Ｈ１１可与石纹电鳐，比目鱼肌肉，大鼠脑，牛红细胞ＡＣｈＥ及     

Effect of papaverine on acetylcholinesterase in rat brain

Papaverine administration produced significant increases in acetylcholinesterase activity in cerebral cortex and striatum of rat brain. Two related compounds, tetrahydropapaverine and tetrahydropapaveroline, also gave similar effects. However, their actions seem to be indirect because papaverine has noin vitro effect on the enzymatic activity.     

Regioselective synthesis,biological evaluation,and molecular docking of dihydropyrimidin‐4‐ols as acetylcholinesterase inhibitors

A new series of 3,6‐disubstituted 2‐(methylthio)‐4‐(trifluoromethyl)‐3,4‐dihydropyrimidin‐4‐ols displaying methyl, phenyl, aryl, and heteroaryl groups at the 6‐position; and methyl, ethyl, allyl, and phenyl groups at the 3‐position of the dihydropyrimidine ring, were synthesized and evaluated in vitro for acetylcholinesterase inhibitory activity. Seven compounds showed activity with IC₅₀ values in the lower micromolar range. The compound 4‐trifluoromethyl‐6‐(4‐fluorophenyl)‐3‐methyl‐2‐methylthio‐3,4‐dihydropyrimidin‐4‐ol ( 6e ) had the best inhibitory activity (IC₅₀ 2.2 ± 0.9 μm ) and this inhibition was characterized as competitive. The molecular docking study showed that the acetylcholinesterase enzyme accommodates compound 6e in its catalytic site. The enantiomers of compound 6e , present similar interactions: π–π stacking interactions between the aromatic ring of the ligand's 4‐fluorophenyl moiety and the aromatic rings of the electron‐rich Trp84; and H‐bonds between the hydroxyl group of Tyr121 and the hydroxyl moiety from 6e . The antioxidant effect of the dihydropyrimidin‐4‐ols was also investigated.     

Role of molecular isoforms of acetylcholinesterase in learning and memory functions

In the present study, activity of salt soluble (SS) G1 and detergent soluble (DS) G4 molecular isoforms of acetylcholinesterase (AChE) has been investigated in rat brain areas in trained (learned), scopolamine (amnesic) and Tacrine (anti-dementic) treated rats to find out their role in learning and memory functions. AChE was estimated spectrophotometrically at 412 nm in rat brain areas. Isolation and partial purification of molecular isoforms G1 and G4 of AChE was done by gel filtration chromatography. Passive avoidance was used to test learning and memory functions. AChE activity was altered in both the fractions SS and DS of different brain areas following passive avoidance in control, scopolamine treated, tacrine treated and tacrine treatment in scopolamine pretreated rats. The peak AChE activity obtained in the DS (fraction 9) and the SS (fraction 13) fraction following gel filtration chromatography. On the basis of molecular weight fraction 9 (DS) and 13 (SS) represent the G4 and G1, respectively. The pattern of changes in the AChE activity of G1 isoform (fraction 13 of SS) and G4 isoform (fraction 9 of DS) in brain areas were similar to those of SS and DS fraction, respectively. In hippocampus, AChE activity in the fraction G1 isoform (fraction 13 of SS) was decreased only in tacrine treated rats but AChE activity in the G4 isoform (fraction 9 of DS) was decreased in both trained and tacrine treated rats. Changes in activity of G4 isoform of AChE in hippocampus could be correlated with passive avoidance learning, scopolamine induced deficit in passive avoidance and reversal of scopolamine deficit by tacrine.     

抗乙酰胆碱酯酶单克隆抗体3F3的免疫亲和层析及其Fab对酶活性的影响

将电鳐电器官AChE固相化,以免疫亲和层析法提纯抗电鳐电器官AChE单克隆抗体3F3。纯化的3F3单克隆抗体在半胱氨酸存在下经木瓜蛋白酶切割后,用免疫亲和层析及蛋白A琼脂糖凝胶亲和层析柱分离提纯3F3的Fab肽片。单克隆抗体3F3的Fab肽片能抑制AChE活性,Fab量愈多,对AChE活性的抑制愈强,达到50％抑制需要的Fab量为2.52μg,为完整IgG的3.5倍,以摩尔数计约为完整IgG的10.5倍。     

Reanalysis with optimized power of red blood cell acetylcholinesterase activity from a 1-year dietary treatment of dogs to chlorpyrifos

A no-observed-effect level (NOEL) of 0.1 mg/kg/day was reported for inhibition of red blood cell (RBC) acetylcholinesterase (AChE) in two groups of Beagle dogs fed chlorpyrifos (0, 0.01, 0.03, 0.1, 1 or 3 mg/kg/day) in the diet for 1 or 2 years (McCollister et al., Food Cosmet. Toxicol. 12 (1974) 45–61). The statistical analyses were by t-test that had low statistical power due to small sample sizes. Common time points for blood samples in both phases allowed a reanalysis of the grouped data over a 1-year time period. The reanalysis increased statistical power by increasing the sample size to n=14 from n=3 or 4, and decreasing the variance, by statistical step-by-step aggregation of the data from both phases, both sexes, and four sample periods. Factors retained in the ANOVA were dose, sex, and phase (sex-by-dose was not significant). Contrasts with one-sided t-tests indicated the 1 and 3 mg/kg/day groups had significantly inhibited RBC AChE (P<0.0001). At =0.05, the uncorrected one-sided model had 80% power to detect a 12% decrease, 93% power for a 15% decrease, and 99.5% power for a 20% decrease in AChE activity. Overall, the reanalysis had high power to detect a clinically significant decrease in RBC AChE activity, and substantiated the original NOEL for chronic treatment of dogs to dietary chlorpyrifos at 0.1 mg/kg/day.     

Finding of polysaccharide-peptide complexes in Cordyceps militaris and evaluation of its acetylcholinesterase inhibition activity

Acetylcholinesterase (AChE) inhibition enhances learning and cognitive ability for treatment of Alzheimer’s disease. Polysaccharide–peptide complexes were identified in Cordyceps militaris (CPSPs) and characterized for their AChE inhibitory properties. Three polymers (CPSP-F1, -F2, and -F3) were extracted and separated by ultrasound-assisted extraction and dieth-ylaminoethanol (DEAE)–Sepharose CL-6B column chromatography. Polysaccharide–peptide complexes were identified by DEAE–Sepharose CL-6B column chromatography and high-performance gel-filtration chromatography, Fourier transform infrared spectra, amino sugar composition analysis, and β-elimination reaction to identify polysaccharide–peptide bond categories. Separation of CPSP can increase AChE inhibitory activity from the crude poly-saccharide of C. militaris. CPSP-F1 and CPSP-F2 exhibited half maximal inhibitory concentrations of 32.2 ± 0.2 mg/mL and 5.3 ± 0.0 mg/mL. Thus, we identified polysaccharide–peptide complexes from C. militaris and suggest CPSP has great potential in AChE inhibition bioassay.     

Selective effects of carbamate pesticides on rat neuronal nicotinic acetylcholine receptors and rat brain acetylcholinesterase

Effects of commonly used carbamate pesticides on rat neuronal nicotinic acetylcholine receptors expressed in Xenopus laevis oocytes have been investigated using the two-electrode voltage clamp technique. The potencies of these effects have been compared to the potencies of the carbamates to inhibit rat brain acetylcholinesterase. The potency order of six carbamates to inhibit alpha4beta4 nicotinic receptors is fenoxycarb > EPTC > carbaryl, bendiocarb > propoxur > aldicarb with IC50 values ranging from 3 microM for fenoxycarb to 165 microM for propoxur and >1 mM for aldicarb. Conversely, the potency order of these carbamates to inhibit rat brain acetylcholinesterase is bendiocarb > propoxur, aldicarb > carbaryl > EPTC, fenoxycarb with IC50 values ranging from 1 microM for bendiocarb to 17 microM for carbaryl and > mM for EPTC and fenoxycarb. The alpha4beta2, alpha3beta4, and alpha3beta2 nicotinic acetylcholine receptors are inhibited by fenoxycarb, EPTC, and carbaryl with potency orders similar to that for alpha4beta4 receptors. Comparing the potencies of inhibition of the distinct subtypes of nicotinic acetylcholine receptors shows that the alpha3beta2 receptor is less sensitive to inhibition by fenoxycarb and EPTC. The potency of inhibition depends on the carbamate as well as on a combination of alpha and beta subunit properties. It is concluded that carbamate pesticides affect different subtypes of neuronal nicotinic receptors independently of acetylcholinesterase inhibition. This implicates that neuronal nicotinic receptors are additional targets for some carbamate pesticides and that these receptors may contribute to carbamate pesticide toxicology, especially after long-term exposure.     

Combined approach to demonstrate acetylcholinesterase activity changes in the rat brain following tabun intoxication and its treatment

Reactivation effects of K203 and currently available oximes (obidoxime, HI-6) in combination with atropine on acetylcholinesterase activities in the brain parts of rats poisoned with tabun were studied. The activity was determined by quantitative histochemical and biochemical methods correlating between them very well. The tabun-induced changes in acetylcholinsterase activity as well as in reactivation potency of reactivators used were different in various parts of the brain. Pontomedullar area seems to be important for observed changes following tabun intoxication and its treatment. From the oximes studied, the reactivation effect of K203 was comparable with obidoxime; HI-6 was ineffective. Combination of bio- and histochemical methods allow fine differentiation among the action of different oximes following tabun poisoning.     

多奈哌齐对脑组织及血液中乙酰胆碱酯酶活性的影响

目的研究多奈哌齐单次给药对乙酰胆碱酯酶(AChE)活力的影响以及其与脑组织AChE活力变化的相关性。方法受试小鼠随机分为对照组和多奈哌齐组。对照组(n=8)生理盐水0.2 mL/10 g灌胃,于给药后于2 h取血、取脑;多奈哌齐组(7亚组,每组8只)于多奈哌齐灌胃后于0.5、1、2、4、8、12和24 h各时间点取血、取脑。采用AChE测定试剂盒测定全血、血浆及脑组织AChE活性,考马斯亮蓝试剂盒测定脑组织匀浆蛋白含量。结果与对照组比较,多奈哌齐各亚组全血、血浆中AChE的活力改变无统计学意义(P>0.05);各亚组脑匀浆AChE活力改变无统计学意义(P>0.05),但2 h亚组脑匀浆中AChE活力改变显著(P<0.05)。提示全血和血浆AChE活力改变与脑组织AChE活力变化并无显著关联。结论多奈哌齐0.625 mg/kg单次给药后2 h脑组织AChE活力显著降低,但对血液AChE活性无显著影响,且血液中酶活力变化与脑组织酶活力变化无显著关联。