scholarly journals AN α-PARTICLE AUTORADIOGRAPHIC METHOD FOR QUANTIFYING THE INHIBITION OF ACETYLCHOLINESTERASE AT THE MYONEURAL JUNCTION

1969 ◽  
Vol 17 (4) ◽  
pp. 244-248 ◽  
Author(s):  
ROBERT R. LANDOLT ◽  
PAUL L. ZIEMER ◽  
JOHN E. CHRISTIAN
Keyword(s):  
Production Rate ◽  
Acetylcholinesterase Activity ◽  
Acetylcholinesterase Inhibition ◽  
Myoneural Junction ◽  
Inhibition Study ◽  
Tissue Sections ◽  
Autoradiographic Method ◽  
Irreversible Inhibitors ◽  
Sigmoidal Curve ◽  
Α Particles

An existing histochemical method was adapted to α-particle autoradiography to provide a means of quantifying acetylcholinesterase inhibition at myoneural junctions. The α-particles were emitted from polonium 210 which was present in the precipitate after staining. A technique was designed for counting areas of dense α-particle tracks on the autoradiograms which corresponded to sites of acetylcholinesterase activity. An experiment was performed which showed that the track production rate was consistent for several diaphragm sections when incubated under identical conditions with no inhibitor. Tissue sections of this type, representing zero inhibition, were used as controls for inhibitor studies. It was also demonstrated that the track production rate was constant during the different exposure times used in the inhibition study. Diisopropylfluorophosphate was used to evaluate the autoradiographic method of quantifying acetylcholinesterase inhibition. A plot of log inhibitor concentration against percentage inhibition resulted in a smooth sigmoidal curve which is typical of irreversible inhibitors.

scholarly journals Synthesis, Biological Evaluation and Docking Studies of Chalcone and Flavone Analogs as Antioxidants and Acetylcholinesterase Inhibitors

2019 ◽  
Vol 9 (3) ◽  
pp. 410 ◽  
Author(s):  
Laura Díaz-Rubio ◽  
Rufina Hernández-Martínez ◽  
Arturo Estolano-Cobián ◽  
Daniel Chávez-Velasco ◽  
Ricardo Salazar-Aranda ◽  
...  
Keyword(s):  
Acetylcholinesterase Inhibitors ◽  
Acetylcholinesterase Activity ◽  
Biological Evaluation ◽  
Chemotherapeutic Agents ◽  
Acetylcholinesterase Inhibition ◽  
Ache Inhibitors ◽  
Antioxidant Agents ◽  
Wide Range ◽  
Β Carotene

Several oxidative processes are related to a wide range of human chronic and degenerative diseases, like Alzheimer’s disease, which also has been related to cholinergic processes. Therefore, search for new or improved antioxidant molecules with acetylcholinesterase activity is essential to offer alternative chemotherapeutic agents to support current drug therapies. A series of chalcone (2a–2k) and flavone (3a–3k) analogs were synthesized, characterized, and evaluated as acetylcholinesterase (AChE) inhibitors, and antioxidant agents using 1,1-diphenyl-2-picrylhydrazyl (DPPH•), 2-2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS•), and β-carotene/linoleic acid bleaching assay. Compounds more active were 3j and 2k in DPPH with EC50 of 1 × 10−8 and 5.4 × 10−3 μg/mL, respectively; 2g and 3i in ABTS (1.14 × 10−2 and 1.9 × 10−3 μg/mL); 2e, 2f, 3f, 2j, and 3j exceeded the α-tocopherol control in the β-carotene assay (98–99% of antioxidant activity). At acetylcholinesterase inhibition assay, flavones were more active than chalcones; the best results were compounds 2d and 3d (IC50 21.5 and 26.8 µg/mL, respectively), suggesting that the presence of the nitro group enhances the inhibitory activity. The docking of these two structures were made to understand their interactions with the AChE receptor. Although further in vivo testing must be performed, our results represent an important step towards the identification of improved antioxidants and acetylcholinesterase inhibitors.

scholarly journals Kinetics of Torpedo californica acetylcholinesterase inhibition by bisnorcymserine and crystal structure of the complex with its leaving group

2012 ◽  
Vol 444 (2) ◽  
pp. 269-277 ◽  
Author(s):  
Cecilia Bartolucci ◽  
Jure Stojan ◽  
Qian-sheng Yu ◽  
Nigel H. Greig ◽  
Doriano Lamba
Keyword(s):  
Crystal Structure ◽  
Kinetic Studies ◽  
Catalytic Triad ◽  
Acetylcholinesterase Inhibition ◽  
Inhibition Mechanism ◽  
Torpedo Californica ◽  
Irreversible Inhibitors ◽  
Leaving Group ◽  
Ad Alzheimer’S Disease ◽  
Kinetics Of

Natural and synthetic carbamates act as pseudo-irreversible inhibitors of AChE (acetylcholinesterase) as well as BChE (butyrylcholinesterase), two enzymes involved in neuronal function as well as in the development and progression of AD (Alzheimer's disease). The AChE mode of action is characterized by a rapid carbamoylation of the active-site Ser200 with release of a leaving group followed by a slow regeneration of enzyme action due to subsequent decarbamoylation. The experimental AD therapeutic bisnorcymserine, a synthetic carbamate, shows an interesting activity and selectivity for BChE, and its clinical development is currently being pursued. We undertook detailed kinetic studies on the activity of the carbamate bisnorcymserine with Tc (Torpedo californica) AChE and, on the basis of the results, crystallized the complex between TcAChE and bisnorcymserine. The X-ray crystal structure showed only the leaving group, bisnoreseroline, trapped at the bottom of the aromatic enzyme gorge. Specifically, bisnoreseroline interacts in a non-covalent way with Ser200 and His440, disrupting the existing interactions within the catalytic triad, and it stacks with Trp84 at the bottom of the gorge, giving rise to an unprecedented hydrogen-bonding contact. These interactions point to a dominant reversible inhibition mechanism attributable to the leaving group, bisnoreseroline, as revealed by kinetic analysis.

An acetylcholinesterase inhibitor, donepezil, increases anxiety and cortisol levels in adult zebrafish

2020 ◽  
Vol 34 (12) ◽  
pp. 1449-1456 ◽  
Author(s):  
Ana CVV Giacomini ◽  
Barbara W Bueno ◽  
Leticia Marcon ◽  
Naiara Scolari ◽  
Rafael Genario ◽  
...  
Keyword(s):  
Acetylcholinesterase Inhibitor ◽  
Model Organism ◽  
Acetylcholinesterase Activity ◽  
Acetylcholinesterase Inhibition ◽  
Whole Body ◽  
The Novel ◽  
Adult Zebrafish ◽  
Tank Test ◽  
Cortisol Levels ◽  
Brain Acetylcholinesterase

Background: A potent acetylcholinesterase inhibitor, donepezil is a cognitive enhancer clinically used to treat neurodegenerative diseases. However, its complete pharmacological profile beyond cognition remains unclear. The zebrafish ( Danio rerio) is rapidly becoming a powerful novel model organism in neuroscience and central nervous system drug screening. Aim: Here, we characterize the effects of 24-h donepezil administration on anxiety-like behavioral and endocrine responses in adult zebrafish. Methods: We evaluated zebrafish anxiety-like behaviors in the novel tank, the light-dark and the shoaling tests, paralleled by assessing brain acetylcholinesterase activity and whole-body cortisol levels. Results: Overall, donepezil dose-dependently decreased zebrafish locomotor activity in the novel tank test and reduced time in light in the light-dark test, likely representing hypolocomotion and anxiety-like behaviors. Donepezil predictably decreased brain acetylcholinesterase activity, also increasing whole-body cortisol levels, thus further linking acetylcholinesterase inhibition to anxiety-like behavioral and endocrine responses. Conclusion: Collectively, these findings suggest negative modulation of zebrafish affective behavior by donepezil, support the key role of cholinergic mechanisms in behavioral regulation in zebrafish, and reinforce the growing utility of zebrafish models for studying complex behavioral processess and their neuroendocrine and neurochemical regulation.

scholarly journals Application of HPLC-DAD for In Vitro Investigation of Acetylcholinesterase Inhibition Activity of Selected Isoquinoline Alkaloids from Sanguinaria canadensis Extracts

Molecules ◽  
2021 ◽  
Vol 26 (1) ◽  
pp. 230
Author(s):  
Tomasz Tuzimski ◽  
Anna Petruczynik
Keyword(s):  
Plant Extracts ◽  
High Performance ◽  
Acetylcholinesterase Activity ◽  
Hplc Method ◽  
Acetylcholinesterase Inhibition ◽  
Isoquinoline Alkaloids ◽  
Activity Inhibition ◽  
Sanguinaria Canadensis ◽  
In Vitro Investigation

Isoquinoline alkaloids may have a wide range of pharmacological activities. Some of them have acetylcholinesterase activity inhibition. Nowadays, neurodegenerative disorders such as Alzheimer’s disease have become a serious public health problem. Searching for new effective compounds with inhibited acetylcholinesterase activity is one of the most significant challenges of modern scientific research. The aim of this study was the in vitro investigation of acetylcholinesterase activity inhibition of extracts obtained from Sanguinaria canadensis collected before, during and after flowering. The acetylcholinesterase activity inhibition of these extracts has not been previously tested. The aim was also to quantify selected alkaloids in the investigated extracts by high performance liquid chromatography (HPLC). The analyses of alkaloid content were performed using HPLC in reversed phase (RP) mode using Polar RP column and mobile phase containing acetonitrile, water and ionic liquid (IL). The acetylcholinesterase activity inhibition of the tested plant extracts and respective alkaloid standards were examined using high performance liquid chromatography with diode-array detector (HPLC-DAD) for the quantification of 5-thio-2-nitro-benzoic acid, which is the product of the reaction between the thiocholine (product of the hydrolysis of acetylthiocholine reaction) with Ellman reagent. The application of the HPLC method allowed for elimination of absorption of interfering components, for example, alkaloids such as sanguinarine and berberine. It is revealed that the HPLC method can be successfully used for the evaluation of the acetylcholinesterase inhibitory activity in samples such as plant extracts, especially those containing colored components adsorbing at wavelength in the range 405–412 nm. The acetylcholinesterase inhibition activity synergy of pairs of alkaloid standards and mixture of all investigated alkaloids was also determined. Most investigated alkaloids and all Sanguinaria canadensis extracts exhibited very high acetylcholinesterase activity inhibition. IC50 values obtained for alkaloid standards were from 0.36 for berberine to 23.13 µg/mL for protopine and from 61.24 to 89.14 µg/mL for Sanguinaria canadensis extracts. Our investigations demonstrated that these plant extracts can be recommended for further in vivo experiments to confirm their acetylcholinesterase activity inhibition.

scholarly journals Molecular modeling of acetylcholinesterase interaction with irreversible and reversible organophosphorous inhibitors

2011 ◽  
Vol 57 (1) ◽  
pp. 61-76 ◽  
Author(s):  
O.V. Tikhonova ◽  
V.S. Skvortsov ◽  
O.A. Raevsky
Keyword(s):  
Comparative Analysis ◽  
Molecular Modeling ◽  
Three Dimensional ◽  
Acetylcholinesterase Inhibitors ◽  
3D Qsar ◽  
Acetylcholinesterase Inhibition ◽  
Quality Model ◽  
Irreversible Inhibitors ◽  
Qsar Models ◽  
3D Fields

Three-dimensional Quantitative Structure-Аctivity Relationship models were designed for irreversible and reversible acetylcholinesterase inhibitors by molecular modeling methods. In case of irreversible inhibitors CoMFA (the comparative analysis of molecular fields) or CoMSIA (the comparative analysis of indexes of molecular similarity) descriptors together with HYBOT 3D fields provide more statistically valid 3D-QSAR models. This indicates importance of donor-acceptor interactions for irreversible acetylcholinesterase inhibition. In case of reversible organophosphorous inhibitors good quality model for structure-activity relationships was developed using CoMFA fields. The obtained models have good predictive power and can be used for estimation of new organophosphorous compounds inhibitor activity that in turn correlates with toxicity of these compounds.

scholarly journals (-)-Phenserine Ameliorates Contusion Volume, Neuroinflammation, and Behavioral Impairments Induced by Traumatic Brain Injury in Mice

2019 ◽  
Vol 28 (9-10) ◽  
pp. 1183-1196 ◽  
Author(s):  
Shih-Chang Hsueh ◽  
Daniela Lecca ◽  
Nigel H. Greig ◽  
Jia-Yi Wang ◽  
Warren Selman ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Motor Coordination ◽  
Acetylcholinesterase Inhibitor ◽  
Acetylcholinesterase Activity ◽  
Phase Iii ◽  
Acetylcholinesterase Inhibition ◽  
Motor Asymmetry ◽  
Post Injury ◽  
Behavioral Impairments

Traumatic brain injury (TBI), a major cause of mortality and morbidity, affects 10 million people worldwide, with limited treatment options. We have previously shown that (-)-phenserine (Phen), an acetylcholinesterase inhibitor originally designed and tested in clinical phase III trials for Alzheimer’s disease, can reduce neurodegeneration after TBI and reduce cognitive impairments induced by mild TBI. In this study, we used a mouse model of moderate to severe TBI by controlled cortical impact to assess the effects of Phen on post-trauma histochemical and behavioral changes. Animals were treated with Phen (2.5 mg/kg, IP, BID) for 5 days started on the day of injury and the effects were evaluated by behavioral and histological examinations at 1 and 2 weeks after injury. Phen significantly attenuated TBI-induced contusion volume, enlargement of the lateral ventricle, and behavioral impairments in motor asymmetry, sensorimotor functions, motor coordination, and balance functions. The morphology of microglia was shifted to an active from a resting form after TBI, and Phen dramatically reduced the ratio of activated to resting microglia, suggesting that Phen also mitigates neuroinflammation after TBI. While Phen has potent anti-acetylcholinesterase activity, its (+) isomer Posiphen shares many neuroprotective properties but is almost completely devoid of anti-acetylcholinesterase activity. We evaluated Posiphen at a similar dose to Phen and found similar mitigation in lateral ventricular size increase, motor asymmetry, motor coordination, and balance function, suggesting the improvement of these histological and behavioral tests by Phen treatment occur via pathways other than anti-acetylcholinesterase inhibition. However, the reduction of lesion size and improvement of sensorimotor function by Posiphen were much smaller than with equivalent doses of Phen. Taken together, these results show that post-injury treatment with Phen over 5 days significantly ameliorates severity of TBI. These data suggest a potential development of this compound for clinical use in TBI therapy.

scholarly journals DISTRIBUTION OF ESTERASES IN THE MYONEURAL JUNCTION OF THE STRIATED MUSCLE OF THE RAT

1967 ◽  
Vol 15 (7) ◽  
pp. 399-403 ◽  
Author(s):  
O. ERÄNKÖ ◽  
H. TERÄVÄINEN
Keyword(s):  
Esterase Activity ◽  
Striated Muscle ◽  
Acetylcholinesterase Activity ◽  
Nonspecific Esterase ◽  
Selective Inhibitors ◽  
Myoneural Junction ◽  
Terminal Axon ◽  
Naphthyl Acetate ◽  
Nonspecific Esterase Activity

Distribution of esterases in the myoneural junction of the striated muscle of the rat was studied using acetylthiocholine, butyrylthiochobine and α-naphthyl acetate as substrates, together with selective inhibitors. Acetylcholinesterase activity was observed in the peripheral complex of synaptic folds. Nonspecific cholinesterase was detected in the peripheral complex of synaptic folds and the teloglia with approximately equal activities. Nonspecific esterase activity, present in tissues incubated with eserine, was marked in the terminal axon and was also present in the teloglia and synaptic folds.

Correlation between organophosphate poisoning, acetylcholinesterase inhibition, and increased cyclic GMP levels in malathion-treated insects

1977 ◽  
Vol 55 (5) ◽  
pp. 534-542 ◽  
Author(s):  
Robert P. Bodnaryk
Keyword(s):  
Cyclic Gmp ◽  
Time Course ◽  
Acetylcholinesterase Activity ◽  
Acetylcholinesterase Inhibition ◽  
Organophosphate Poisoning ◽  
Abrupt Increase ◽  
Sarcophaga Bullata ◽  
Biochemical Lesion ◽  
Lag Period ◽  
Dose Dependent

Organophosphate poisoning with malathion caused large increases (up to 125 and 440%, respectively) in the level of cyclic GMP in larvae of Mamestra configurata Wlk. and in the fly Sarcophaga bullata Parker. Cyclic AMP was little affected. The malathion-induced increase in cyclic GMP was time and dose dependent. Time-course studies with the head and thorax of S. bullata demonstrated that the increase in cyclic GMP level occurred precipitously after a lag period of about 1 h, during which time the activity of acetylcholinesterase (EC 3.1.1.7) was progressively inhibited. The abrupt increase in cyclic GMP began when acetylcholinesterase activity had been inhibited to a sufficient extent to permit accumulation of acetylcholine. It is suggested that the accumulation of acetylcholine in the malathion-poisoned insects caused cyclic GMP levels to rise.Cyclic GMP may have a role in cholinergic transmission in normally functioning insect neural tissue. Increased levels of cyclic GMP induced by organophosphate and organochlorine (Bodnaryk, R. P. (1976) Can. J. Biochem. 54, 957–962) insecticides appear to be a vital and previously unrecognized biochemical lesion in insects poisoned by these compounds.

scholarly journals Kinetic Evaluation of the Inhibition of Acetylcholinesterase for use as a biosensor

2020 ◽  
Vol 20 (1) ◽  
pp. 99
Author(s):  
R. Bhuvanagayathri ◽  
David K Daniel ◽  
Gnanasundaram Nirmala
Keyword(s):  
Kinetic Parameter ◽  
Mixed Type ◽  
Acetylcholinesterase Activity ◽  
Reaction Rates ◽  
Acetylcholinesterase Inhibition ◽  
Inhibition Rate ◽  
Sensing Element ◽  
Kinetic Evaluation ◽  
Factors Affecting ◽  
Inhibition Rate Constant

The release of pesticides into the environment has increased, and there is a lack of monitoring of these contaminants. Since the conventional methods of monitoring these contaminants are complicated, costly and time-consuming, mechanisms based on acetylcholinesterase inhibition have emerged as simple and rapid tools for such applications. However, theacetylcholinesterase’s effectiveness as a sensing element in such biosensor systems depend­s on the conditions selected to measure acetylcholinesterase activity and the concentration of substrate or inhibitor, which in turn affect the reaction rates. Therefore, in the present work, the factors affecting the acetylcholinesterase activity were investigated and inhibition experiments were carried out to evaluate the kinetic parameters. The inhibition rate constant for acetylcholinesterase Ki was found to be 1.9 ppm. The kinetic parameter Km was found to be 3.8mM and Vmax was found to be 1.3µM/min from the Eadie-Hofstee plot. The kinetic study using Lineweaver-Burk method showed mixed type of inhibition of acetylcholinesterase with carbofuran.

scholarly journals Chemical Profile and Evaluation of the Antioxidant and Anti-Acetylcholinesterase Activities of Annona squamosa L. (Annonaceae) Extracts

Foods ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2343
Author(s):  
Débora Odília Duarte Leite ◽  
Cicera Janaine Camilo ◽  
Carla de Fatima Alves Nonato ◽  
Natália Kelly Gomes de Carvalho ◽  
Gerson Javier Torres Salazar ◽  
...  
Keyword(s):  
Vitamin C ◽  
Acetylcholinesterase Activity ◽  
Seed Extract ◽  
Acetylcholinesterase Inhibition ◽  
Total Phenols ◽  
Annona Squamosa ◽  
Chemical Profile ◽  
Significant Difference ◽  
Ache Inhibitory Activity ◽  
Β Carotene

This study presents the chemical profile of extracts from the pulp and seed of Annona squamosa L., as well as the evaluation of their antioxidant and acetylcholinesterase inhibition activities. In the chemical prospection, qualitative assays were performed, and the contents of total phenols, flavonoids, vitamin C, and carotenoids were quantified. For the compounds identification, analyses of the extracts were performed by liquid chromatography coupled to mass spectrometry. Antioxidant evaluation was performed using the DPPH, ABTS, Fe3+ reduction, 2-DR protection, and β-carotene protection methods. The assay for inhibition of acetylcholinesterase activity was determined using the method described by Ellman. The secondary metabolites identified were anthocyanidins, flavones, flavonols, and alkaloids. Phenol analysis showed a higher quantitative value of total phenols and flavonoids for the seed extract, and the vitamin C content was higher in the pulp extract. There was no significant difference in relation to the carotenoids quantification. The best results obtained for antioxidant activity, for both seed and pulp extracts, were with the ABTS method with IC50 of 0.14 ± 0.02 and 0.38 ± 0.02 mg/mL, respectively. Compared to A. squamosa seed extract, the pulp extract demonstrates higher AChE inhibitory activity with IC50 of 18.82 ± 0.17 µg/mL. A. squamosa is a nutritious food source. The continuity of the studies is fundamental to relate the consumption of this food and its effects on neurodegenerative diseases.

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