The acetylcholinesterase inhibitor BW284c51 is a potent blocker of Torpedo nicotinic AchRs incorporated into the Xenopus oocyte membrane

PubMed Central

Olivera-Bravo, Silvia; Ivorra, Isabel; Morales, Andrés

2004-01-01

This work was aimed to determine if 1,5-bis(4-allyldimethylammoniumphenyl)pentan-3-one dibromide (BW284c51), the most selective acetylcholinesterase inhibitor (AchEI), affects the nicotinic acetylcholine (Ach) receptor (AchR) function. Purified Torpedo nicotinic AchRs were injected into Xenopus laevis oocytes and BW284c51 effects on Ach- and carbamylcholine (Cch)-elicited currents were assessed using the voltage-clamp technique. BW284c51 (up to 1 mM) did not evoke any change in the oocyte membrane conductance. When BW284c51 (10 pM–100 μM) and Ach were coapplied, Ach-evoked currents (IAch) were reversibly inhibited in a concentration-dependent manner (Hill coefficient, 1; IC50, 0.2–0.5 μM for 0.1–1000 μM Ach). Cch-elicited currents showed a similar inhibition by BW284c51. IAch blockade by BW284c51 showed a strong voltage dependence, being only apparent at hyperpolarising potentials. BW284c51 also enhanced IAch desensitisation. BW284c51 changed the Ach concentration-dependence curve of Torpedo AchR response from two-site to single-site kinetics, without noticeably affecting the EC50 value. The BW284c51 blocking effect was highly selective for nicotinic over muscarinic receptors. BW284c51 inhibition potency was stronger than that of tacrine, and similar to that of d-tubocurarine (d-TC). Coapplication of BW284c51 with either tacrine or d-TC revealed synergistic inhibitory effects. Our results indicate that BW284c51 antagonises nicotinic AchRs in a noncompetitive way by blocking the receptor channel, and possibly by other, yet unknown, mechanisms. Therefore, besides acting as a selective AchEI, BW284c51 constitutes a powerful and reversible blocker of nicotinic AchRs that might be used as a valuable tool for understanding their function. PMID:15644872

Discovery of potent and selective acetylcholinesterase (AChE) inhibitors: acacetin 7-O-methyl ether Mannich base derivatives synthesised from easy access natural product naringin.

PubMed

Liu, Hao-Ran; Men, Xue; Gao, Xiao-Hui; Liu, Lin-Bo; Fan, Hao-Qun; Xia, Xin-Hua; Wang, Qiu-An

2018-03-01

Naringin, as a component universal existing in the peel of some fruits or medicinal plants, was usually selected as the material to synthesise bioactive derivates since it was easy to gain with low cost. In present investigation, eight new acacetin-7-O-methyl ether Mannich base derivatives (1-8) were synthesised from naringin. The bioactivity evaluation revealed that most of them exhibited moderate or potent acetylcholinesterase (AChE) inhibitory activity. Among them, compound 7 (IC 50 for AChE = 0.82 ± 0.08 μmol•L -1 , IC 50 for BuChE = 46.30 ± 3.26 μmol•L -1 ) showed a potent activity and high selectivity compared with the positive control Rivastigmine (IC 50 for AChE = 10.54 ± 0.86 μmol•L -1 , IC 50 for BuChE = 0.26 ± 0.08 μmol•L -1 ). The kinetic study suggested that compound 7 bind to AChE with mix-type inhibitory profile. Molecular docking study revealed that compound 7 could combine both catalytic active site (CAS) and peripheral active site (PAS) of AChE with four points (Trp84, Trp279, Tyr70 and Phe330), while it could bind with BuChE via only His 20.

Tertiary amine derivatives of chlorochalcone as acetylcholinesterase (AChE) and buthylcholinesterase (BuChE) inhibitors: the influence of chlorine, alkyl amine side chain and α,β-unsaturated ketone group.

PubMed

Gao, Xiao-Hui; Zhou, Chao; Liu, Hao-Ran; Liu, Lin-Bo; Tang, Jing-Jing; Xia, Xin-Hua

2017-12-01

A new series of tertiary amine derivatives of chlorochalcone (4a∼4l) were designed, synthesized and evaluated for the effect on acetylcholinesterase (AChE) and buthylcholinesterase (BuChE). The results indicated that all compounds revealed moderate or potent inhibitory activity against AChE, and some possessed high selectivity for AChE over BuChE. The structure-activity investigation showed that the substituted position of chlorine significantly influenced the activity and selectivity. The alteration of tertiary amine group also leads to obvious change in bioactivity. Among them, IC 50 of compound 4l against AChE was 0.17 ± 0.06 µmol/L, and the selectivity was 667.2 fold for AChE over BuChE. Molecular docking and enzyme kinetic study on compound 4l suggested that it simultaneously binds to the catalytic active site (CAS) and peripheral anionic site (PAS) of AChE. Further study showed that the pyrazoline derivatives synthesized from chlorochalcones had weaker activity and lower selectivity in inhibiting AChE compared to that of chlorochalcone derivatives.

Discovering New Acetylcholinesterase Inhibitors by Mining the Buzhongyiqi Decoction Recipe Data.

PubMed

Cui, Lu; Wang, Yu; Liu, Zhihong; Chen, Hongzhuan; Wang, Hao; Zhou, Xinxin; Xu, Jun

2015-11-23

Myasthenia gravis (MG) is a neuromuscular disease that is conventionally treated with acetylcholinesterase (AChE) inhibitors, which may not fully remove the symptom for many reasons. When AChE inhibitors do not work, Chinese patients turn to Chinese medicine, such as the Buzhongyiqi decoction (BD), to treat MG. By elucidating the relations between the herbs of the Buzhongyiqi decoction recipe and AChE inhibitors with structure-based and ligand-based drug design methods and chemoinformatics approaches, we have found the key active components of BD. Using these key active components as templates, we have discovered five new AChE inhibitors through virtual screening of a commercial compound library. The new AChE inhibitors have been confirmed with Ellman assays. This study demonstrates that lead identification can be inspired by elucidating Chinese medicine. Since BD is a mixture, further studies against other drug targets are needed.

Downregulated expression of microRNA-124 in pediatric intestinal failure patients modulates macrophages activation by inhibiting STAT3 and AChE

PubMed Central

Xiao, Yong-Tao; Wang, Jun; Lu, Wei; Cao, Yi; Cai, Wei

2016-01-01

Intestinal inflammation plays a critical role in the pathogenesis of intestinal failure (IF). The macrophages are essential to maintain the intestinal homeostasis. However, the underlying mechanisms of intestinal macrophages activation remain poorly understood. Since microRNAs (miRNAs) have pivotal roles in regulation of immune responses, here we aimed to investigate the role of miR-124 in the activation of intestinal macrophages. In this study, we showed that the intestinal macrophages increased in pediatric IF patients and resulted in the induction of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). The miRNA fluorescence in situ hybridization analysis showed that the expression of miR-124 significantly reduced in intestinal macrophages in IF patients. Overexpression of miR-124 was sufficient to inhibit intestinal macrophages activation by attenuating production of IL-6 and TNF-α. Further studies showed that miR-124 could directly target the 3′-untranslated region of both signal transducer and activator of transcription 3 (STAT3) and acetylcholinesterase (AChE) mRNAs, and suppress their protein expressions. The AChE potentially negates the cholinergic anti-inflammatory signal by hydrolyzing the acetylcholine. We here showed that intestinal macrophages increasingly expressed the AChE and STAT3 in IF patients when compared with controls. The inhibitors against to STAT3 and AChE significantly suppressed the lipopolysaccharides-induced IL-6 and TNF-α production in macrophages. Taken together, these findings highlight an important role for miR-124 in the regulation of intestinal macrophages activation, and suggest a potential application of miR-124 in pediatric IF treatment regarding as suppressing intestinal inflammation. PMID:27977009

Cholinesterase inhibitors modify the activity of intrinsic cardiac neurons.

PubMed

Darvesh, Sultan; Arora, Rakesh C; Martin, Earl; Magee, David; Hopkins, David A; Armour, J Andrew

2004-08-01

Cholinesterase inhibitors used to treat the symptoms of Alzheimer's disease (AD) inhibit both acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), albeit to different degrees. Because central and peripheral neurons, including intrinsic cardiac neurons located on the surface of the mammalian heart, express both BuChE and AChE, we studied spontaneously active intrinsic cardiac neurons in the pig as a model to assess the effects of inhibition of AChE compared to BuChE. Neuroanatomical experiments showed that some porcine intrinsic cardiac neurons expressed AChE and/or BuChE. Enzyme kinetic experiments with cholinesterase inhibitors, namely, donepezil, galantamine, (+/-) huperzine A, metrifonate, rivastigmine, and tetrahydroaminoacridine, demonstrated that these compounds differentially inhibited porcine AChE and BuChE. Donepezil and (+/-) huperzine A were better reversible inhibitors of AChE, and galantamine equally inhibited both the enzymes. Tetrahydroaminoacridine was a better reversible inhibitor of BuChE. Rivastigmine caused more rapid inactivation of BuChE as compared to AChE. Neurophysiological studies showed that acetylcholine and butyrylcholine increase or decrease the spontaneous activity of the intrinsic cardiac neurons. Donepezil, galantamine, (+/-) huperzine A, and tetrahydroaminoacridine changed spontaneous neuronal activity by about 30-35 impulses per minute, while rivastigmine changed it by approximately 100 impulses per minute. It is concluded that (i) inhibition of AChE and BuChE directly affects the porcine intrinsic cardiac nervous system, (ii) the intrinsic cardiac nervous system represents a suitable model for examining the effects of cholinesterase inhibitors on mammalian neurons in vivo, and (iii) the activity of intrinsic cardiac neurons may be affected by pharmacological agents that inhibit cholinesterases.

Inhibition of neutral endopeptidase increases airway responsiveness to ACh in nonsensitized normal rats.

PubMed

Chiba, Y; Misawa, M

1995-02-01

The effects of sensory neuropeptides on the airway responsiveness to acetylcholine (ACh) were investigated in normal nonsensitized rats. The airway responsiveness to inhaled ACh was significantly increased after treatment with neurokinin A (NKA; 0.001%) or substance P (SP; 0.01%) aerosol in the presence of the neutral endopeptidase (NEP) inhibitor. NKA had a more potent effect than SP. Interestingly, the intravenous treatment with NEP inhibitor alone also induced airway hyperresponsiveness (AHR) to inhaled ACh. This AHR was significantly attenuated by pretreatment with a nonselective NK-receptor antagonist, [D-Pro2,D-Trp7,9]SP, systemic capsaicin, or bilateral cervical vagotomy, indicating that decreased NEP activity results in accumulation of endogenous sensory neuropeptide(s) and enhancement of vagal reflex to cause AHR. The airway responsiveness to ACh of isolated left main bronchus was also increased after treatment with 10(-6) M NKA, but not SP, together with 10(-6) M phosphoramidon. This in vitro AHR to ACh induced by phosphoramidon plus NKA was significantly attenuated by pretreatment with 10(-6) M tetrodotoxin. These findings suggest that overaccumulated sensory neuropeptides, especially NKA, may enhance the probability of transmitter release, probably via NK2 receptors, and that the enhanced transmitter release might be involved in AHR in rats.

Prenylated xanthones from mangosteen as promising cholinesterase inhibitors and their molecular docking studies.

PubMed

Khaw, K Y; Choi, S B; Tan, S C; Wahab, H A; Chan, K L; Murugaiyah, V

2014-09-25

Garcinia mangostana is a well-known tropical plant found mostly in South East Asia. The present study investigated acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities of G. mangostana extract and its chemical constituents using Ellman's colorimetric method. Cholinesterase inhibitory-guided approach led to identification of six bioactive prenylated xanthones showing moderate to potent cholinesterases inhibition with IC50 values of lower than 20.5 μM. The most potent inhibitor of AChE was garcinone C while γ-mangostin was the most potent inhibitor of BChE with IC50 values of 1.24 and 1.78 μM, respectively. Among the xanthones, mangostanol, 3-isomangostin, garcinone C and α-mangostin are AChE selective inhibitors, 8-deoxygartanin is a BChE selective inhibitor while γ-mangostin is a dual inhibitor. Preliminary structure-activity relationship suggests the importance of the C-8 prenyl and C-7 hydroxy groups for good AChE and BChE inhibitory activities. The enzyme kinetic studies indicate that both α-mangostin and garcinone C are mixed-mode inhibitors, while γ-mangostin is a non-competitive inhibitor of AChE. In contrast, both γ-mangostin and garcinone C are uncompetitive inhibitors, while α-mangostin is a mixed-mode inhibitor of BChE. Molecular docking studies revealed that α-mangostin, γ-mangostin and garcinone C interacts differently with the five important regions of AChE and BChE. The nature of protein-ligand interactions is mainly hydrophobic and hydrogen bonding. These bioactive prenylated xanthones are worthy for further investigations. Copyright © 2014 Elsevier GmbH. All rights reserved.

Novel structural hybrids of pyrazolobenzothiazines with benzimidazoles as cholinesterase inhibitors.

PubMed

Aslam, Sana; Zaib, Sumera; Ahmad, Matloob; Gardiner, John M; Ahmad, Aqeel; Hameed, Abdul; Furtmann, Norbert; Gütschow, Michael; Bajorath, Jürgen; Iqbal, Jamshed

2014-05-06

Two series of novel pyrazolobenzothiazine-based hybrid compounds were efficiently synthesized starting from saccharin sodium salt. Pyrazolo[4,3-c][1,2]benzothiazine scaffolds were N-arylated by using p-fluorobenzaldehyde, followed by the incorporation of a benzimidazole or similar ring systems by treatment with arylenediamines. These phenylene-connected hybrid compounds were investigated as potential inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Compounds 12d and 12k were the most potent AChE inhibitors with IC50 values of 11 and 13 nM, respectively, while 6j (IC50 = 17 nM) proved to be the most active inhibitor against BuChE with remarkable selectivity for BuChE over AChE. Molecular docking studies were also performed on human AChE and BuChE to suggest possible binding modes in which the inhibitor's extended structure is accommodated along the active site gorge of both enzymes. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

The structure-AChE inhibitory activity relationships study in a series of pyridazine analogues.

PubMed

Saracoglu, M; Kandemirli, F

2009-07-01

The structure-activity relationships (SAR) are investigated by means of the Electronic-Topological Method (ETM) followed by the Neural Networks application (ETM-NN) for a class of anti-cholinesterase inhibitors (AChE, 53 molecules) being pyridazine derivatives. AChE activities of the series were measured in IC(50) units, and relative to the activity levels, the series was partitioned into classes of active and inactive compounds. Based on pharmacophores and antipharmacophores calculated by the ETM-software as sub-matrices containing important spatial and electronic characteristics, a system for the activity prognostication is developed. Input data for the ETM were taken as the results of conformational and quantum-mechanics calculations. To predict the activity, we used one of the most well known neural networks, namely, the feed-forward neural networks (FFNNs) trained with the back propagation algorithm. The supervised learning was performed using a variant of FFNN known as the Associative Neural Networks (ASNN). The result of the testing revealed that the high ETM's ability of predicting both activity and inactivity of potential AChE inhibitors. Analysis of HOMOs for the compounds containing Ph1 and APh1 has shown that atoms with the highest values of the atomic orbital coefficients are mainly those atoms that enter into the pharmacophores. Thus, the set of pharmacophores and antipharmacophores found as the result of this study forms a basis for a system of the anti-cholinesterase activity prediction.

A conformational restriction approach to the development of dual inhibitors of acetylcholinesterase and serotonin transporter as potential agents for Alzheimer's disease.

PubMed

Toda, Narihiro; Tago, Keiko; Marumoto, Shinji; Takami, Kazuko; Ori, Mayuko; Yamada, Naho; Koyama, Kazuo; Naruto, Shunji; Abe, Kazumi; Yamazaki, Reina; Hara, Takao; Aoyagi, Atsushi; Abe, Yasuyuki; Kaneko, Tsugio; Kogen, Hiroshi

2003-10-01

Alzheimer's disease (AD) has been treated with acetylcholinesterase (AChE) inhibitors such as donepezil. However, the clinical usefulness of AChE inhibitors is limited mainly due to their adverse peripheral effects. Depression seen in AD patients has been treated with serotonin transporter (SERT) inhibitors. We considered that combining SERT and AChE inhibition could improve the clinical usefulness of AChE inhibitors. In a previous paper, we found a potential dual inhibitor, 1, of AChE (IC50=101 nM) and SERT (IC50=42 nM), but its AChE inhibition activity was less than donepezil (IC50=10 nM). Here, we report the conformationally restricted (R)-18a considerably enhanced inhibitory activity against AChE (IC50=14 nM) and SERT (IC50=6 nM).

AChE Inhibitors and NMDA Receptor Antagonists in Advanced Alzheimer's Disease.

PubMed

Glynn-Servedio, Brianna E; Ranola, Trisha Seys

2017-09-01

The objective of this article is to review the available evidence for duration of treatment with, and considerations for discontinuation of, acetylcholinesterase inhibitors and N-methyl-d-aspartate receptor antagonists in Alzheimer's disease. Literature searches of clinical trials and meta-analyses were conducted using PubMed with the search terms Alzheimer's, dementia, donepezil, galantamine, memantine, and rivastigmine. References from included trials were also used to find additional citations. 2,925 articles were initially identified. Twenty-one studies were included that looked at the use of acetylcholinesterase inhibitors and/or memantine in the treatment of moderate-to-severe Alzheimer's dementia. Several clinical trials have demonstrated small improvements in measures of cognition and activities of daily living with medications used to treat dementia. However, not all patients will benefit from treatment, and the impact of treatment on long-term outcomes, including institutionalization, remains unclear. This paper reviews the available data to support the use of acetylcholinesterase inhibitors and/or memantine in patients with advanced Alzheimer's disease, including those in nursing facilities, and reviews recommendations for consideration of therapy discontinuation. The evidence to support a specific time frame for discontinuation of Alzheimer's disease treatment is limited. It is reasonable to stop a medication if there is no noticeable benefit after the first three months of treatment or once a patient's dementia progresses to a point where there would be no meaningful benefit from continued therapy.

Cholinesterase inhibitors from botanicals

PubMed Central

Ahmed, Faiyaz; Ghalib, Raza Murad; Sasikala, P.; Ahmed, K. K. Mueen

2013-01-01

Alzheimer's disease (AD) is a progressive neurodegenerative disease, wherein a progressive loss of cholinergic synapses occurs in hippocampus and neocortex. Decreased concentration of the neurotransmitter, acetylcholine (ACh), appears to be critical element in the development of dementia, and the most appropriate therapeutic approach to treat AD and other form of dementia is to restore acetylcholine levels by inhibiting both major form of cholinesterase: Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Consequently, researches have focused their attention towards finding cholinesterase inhibitors from natural products. A large number of such inhibitors have been isolated from medicinal plants. This review presents a comprehensive account of the advances in field of cholinesterase inhibitor phytoconstituents. The structures of some important phytoconstituents (collected through www.Chemspider.com) are also presented and the scope for future research is discussed. PMID:24347920

Cholinesterase inhibitor (Altenuene) from an endophytic fungus Alternaria alternata: optimization, purification and characterization.

PubMed

Bhagat, J; Kaur, A; Kaur, R; Yadav, A K; Sharma, V; Chadha, B S

2016-10-01

The aim of this study was to screen endophytic fungi isolated from Vinca rosea for their potential to produce acetylcholinesterase (AChE) inhibitors. Endophytic fungi isolated from V. rosea (Catharanthus roseus), were screened for AChE inhibitor production using Ellman's method. Maximum inhibition against AChE (78%) was observed in an isolate VS-10, identified to be Alternaria alternata on morphological and molecular basis. The isolate also inhibited butyrylcholinesterase (73%). Significant increase (1·3 fold) was achieved after optimization of process parameters using one variable at time approach. The inhibitor was purified using chromatographic techniques. The structure elucidation of the inhibitor was carried out using spectroscopic techniques and was identified to be 'altenuene'. The purified inhibitor possessed antioxidant potential as revealed by dot blot assay. The insecticidal potential of purified inhibitor was evaluated by feeding Spodoptora litura on diet amended with inhibitor. It evinced significant larval mortality. Endophytic A. alternata can serve as a source of dual cholinesterase inhibitor 'altenuene' with significant antioxidant and insecticidal activity. This is the first report on acetylcholinestearse inhibitory activity of altenuene. Alternaria alternata has the potential to produce a dual ChE inhibitor with antioxidant activity useful in the treatment of neurodegenerative disorders and in agriculture as biocontrol agent. © 2016 The Society for Applied Microbiology.

Cellular Membrane Phospholipids Act as a Depository for Quaternary Amine containing Drugs thus competing with the Acetylcholine / Nicotinic Receptor

PubMed Central

Barbacci, Damon; Jackson, Shelley N.; Muller, Ludovic; Egan, Thomas; Lewis, Ernest K.; Schultz, J. Albert; Woods, Amina S.

2014-01-01

We previously demonstrated that ammonium- or guanidinium- phosphate interactions are key to forming non-covalent complexes (NCXs) through salt bridge formation with G-protein coupled receptors (GPCR), which are immersed in the cell membrane's lipids. The present work highlights MALDI ion mobility coupled to orthogonal time-of-flight mass spectrometry (MALDI IM oTOF MS) as a method to determine qualitative and relative quantitative affinity of drugs to form NCXs with targeted GPCRs' epitopes in a model system using, bis-quaternary amine based drugs, α- and β- subunit epitopes of the nicotinic acetylcholine receptor' (nAChR) and phospholipids. Bis-quaternary amines proved to have a strong affinity for all nAChR epitopes and negatively charged phospholipids, even in the presence of the physiological neurotransmitter acetylcholine. Ion mobility baseline separated isobaric phosphatidyl ethanolamine and a matrix cluster, providing an accurate estimate for phospholipid counts. Overall this technique is a powerful method for screening drugs' interactions with targeted lipids and protein respectively containing quaternary amines and guanidinium moieties. PMID:22506649

Lead identification of acetylcholinesterase inhibitors-histamine H3 receptor antagonists from molecular modeling.

PubMed

Bembenek, Scott D; Keith, John M; Letavic, Michael A; Apodaca, Richard; Barbier, Ann J; Dvorak, Lisa; Aluisio, Leah; Miller, Kirsten L; Lovenberg, Timothy W; Carruthers, Nicholas I

2008-03-15

Currently, the only clinically effective treatment for Alzheimer's disease (AD) is the use of acetylcholinesterase (AChE) inhibitors. These inhibitors have limited efficacy in that they only treat the symptoms and not the disease itself. Additionally, they often have unpleasant side effects. Here we consider the viability of a single molecule having the actions of both an AChE inhibitor and histamine H(3) receptor antagonist. Both histamine H(3) receptor antagonists and AChE inhibitors improve and augment cholinergic neurotransmission in the cortex. However, whereas an AChE inhibitor will impart its effect everywhere, a histamine H(3) antagonist will raise acetylcholine levels mostly in the brain as its mode of action will primarily be on the central nervous system. Therefore, the combination of both activities in a single molecule could be advantageous. Indeed, studies suggest an appropriate dual-acting compound may offer the desired therapeutic effect with fewer unpleasant side effects [CNS Drugs2004, 18, 827]. Further, recent studies(2) indicate the peripheral anionic site (PAS) of AChE interacts with the beta-amyloid (betaA) peptide. Consequently, a molecule capable of disrupting this interaction may have a significant impact on the production of or the aggregation of betaA. This may result in slowing down the progression of the disease rather than only treating the symptoms as current therapies do. Here, we detail how the use of the available crystal structure information, pharmacophore modeling and docking (automated, manual, classical, and QM/MM) lead to the identification of an AChE inhibitor-histamine H(3) receptor antagonist. Further, based on our models we speculate that this dual-acting compound may interact with the PAS. Such a dual-acting compound may be able to affect the pathology of AD in addition to providing symptomatic relief.

Novel Triazole-Quinoline Derivatives as Selective Dual Binding Site Acetylcholinesterase Inhibitors.

PubMed

Mantoani, Susimaire P; Chierrito, Talita P C; Vilela, Adriana F L; Cardoso, Carmen L; Martínez, Ana; Carvalho, Ivone

2016-02-05

Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder worldwide. Currently, the only strategy for palliative treatment of AD is to inhibit acetylcholinesterase (AChE) in order to increase the concentration of acetylcholine in the synaptic cleft. Evidence indicates that AChE also interacts with the β-amyloid (Aβ) protein, acting as a chaperone and increasing the number and neurotoxicity of Aβ fibrils. It is known that AChE has two binding sites: the peripheral site, responsible for the interactions with Aβ, and the catalytic site, related with acetylcholine hydrolysis. In this work, we reported the synthesis and biological evaluation of a library of new tacrine-donepezil hybrids, as a potential dual binding site AChE inhibitor, containing a triazole-quinoline system. The synthesis of hybrids was performed in four steps using the click chemistry strategy. These compounds were evaluated as hAChE and hBChE inhibitors, and some derivatives showed IC50 values in the micro-molar range and were remarkably selective towards hAChE. Kinetic assays and molecular modeling studies confirm that these compounds block both catalytic and peripheral AChE sites. These results are quite interesting since the triazole-quinoline system is a new structural scaffold for AChE inhibitors. Furthermore, the synthetic approach is very efficient for the preparation of target compounds, allowing a further fruitful new chemical library optimization.

Electronic structure calculations toward new potentially AChE inhibitors

NASA Astrophysics Data System (ADS)

de Paula, A. A. N.; Martins, J. B. L.; Gargano, R.; dos Santos, M. L.; Romeiro, L. A. S.

2007-10-01

The main purpose of this study was the use of natural non-isoprenoid phenolic lipid of cashew nut shell liquid from Anacardium occidentale as lead material for generating new potentially candidates of acetylcholinesterase inhibitors. Therefore, we studied the electronic structure of 15 molecules derivatives from the cardanol using the following groups: methyl, acetyl, N, N-dimethylcarbamoyl, N, N-dimethylamine, N, N-diethylamine, piperidine, pyrrolidine, and N-benzylamine. The calculations were performed at RHF level using 6-31G, 6-31G(d), 6-31+G(d) and 6-311G(d,p) basis functions. Among the proposed compounds we found that the structures with substitution by acetyl, N, N-dimethylcarbamoyl, N, N-dimethylamine, and pyrrolidine groups were better correlated to rivastigmine indicating possible activity.

Elaborate ligand-based modeling coupled with QSAR analysis and in silico screening reveal new potent acetylcholinesterase inhibitors.

PubMed

Abuhamdah, Sawsan; Habash, Maha; Taha, Mutasem O

2013-12-01

Inhibition of the enzyme acetylcholinesterase (AChE) has been shown to alleviate neurodegenerative diseases prompting several attempts to discover and optimize new AChE inhibitors. In this direction, we explored the pharmacophoric space of 85 AChE inhibitors to identify high quality pharmacophores. Subsequently, we implemented genetic algorithm-based quantitative structure-activity relationship (QSAR) modeling to select optimal combination of pharmacophoric models and 2D physicochemical descriptors capable of explaining bioactivity variation among training compounds (r2(68)=0.94, F-statistic=125.8, r2 LOO=0.92, r2 PRESS against 17 external test inhibitors = 0.84). Two orthogonal pharmacophores emerged in the QSAR equation suggesting the existence of at least two binding modes accessible to ligands within AChE binding pocket. The successful pharmacophores were comparable with crystallographically resolved AChE binding pocket. We employed the pharmacophoric models and associated QSAR equation to screen the national cancer institute list of compounds. Twenty-four low micromolar AChE inhibitors were identified. The most potent gave IC50 value of 1.0 μM.

Protein-mimicking nanowire-inspired electro-catalytic biosensor for probing acetylcholinesterase activity and its inhibitors.

PubMed

Zhang, Qingqing; Hu, Yufang; Wu, Di; Ma, Shaohua; Wang, Jiao; Rao, Jiajia; Xu, Lihua; Xu, Huan; Shao, Huili; Guo, Zhiyong; Wang, Sui

2018-06-01

A highly sensitive electrochemical biosensor based on the synthetized L-Cysteine-Ag(I) coordination polymer (L-Cys-Ag(I) CP), which looks like a protein-mimicking nanowire, was constructed to detect acetylcholinesterase (AChE) activity and screen its inhibitors. This sensing strategy involves the reaction of acetylcholine chloride (ACh) with acetylcholinesterase (AChE) to form choline that is in turn catalytically oxidized by choline oxidase (ChOx) to produce hydrogen peroxide (H 2 O 2 ), thus L-Cys-Ag(I) CP possesses the electro-catalytic property to H 2 O 2 reduction. Herein, the protein-mimicking nanowire-based platform was capable of investigating successive of H 2 O 2 effectively by amperometric i-t (current-time) response, and was further applied for the turn-on electrochemical detection of AChE activity. The proposed sensor is highly sensitive (limit of detection is 0.0006 U/L) and is feasible for screening inhibitors of AChE. The model for AChE inhibition was further established and two traditional AChE inhibitors (donepezil and tacrine) were employed to verify the feasibility of the system. The IC 5 0 of donepezil and tacrine were estimated to be 1.4 nM and 3.5 nM, respectively. The developed protocol provides a new and promising platform for probing AChE activity and screening its inhibitors with low cost, high sensitivity and selectivity. Copyright © 2018 Elsevier B.V. All rights reserved.

Exposure to acetylcholinesterase inhibitors alters the physiology and motor function of honeybees.

PubMed

Williamson, Sally M; Moffat, Christopher; Gomersall, Martha A E; Saranzewa, Nastja; Connolly, Christopher N; Wright, Geraldine A

2013-01-01

Cholinergic signaling is fundamental to neuromuscular function in most organisms. Sub-lethal doses of neurotoxic pesticides that target cholinergic signaling can alter the behavior of insects in subtle ways; their influence on non-target organisms may not be readily apparent in simple mortality studies. Beneficial arthropods such as honeybees perform sophisticated behavioral sequences during foraging that, if influenced by pesticides, could impair foraging success and reduce colony health. Here, we investigate the behavioral effects on honeybees of exposure to a selection of pesticides that target cholinergic signaling by inhibiting acetylcholinesterase (AChE). To examine how continued exposure to AChE inhibitors affected motor function, we fed adult foraging worker honeybees sub-lethal concentrations of these compounds in sucrose solution for 24 h. Using an assay for locomotion in bees, we scored walking, stopped, grooming, and upside down behavior continuously for 15 min. At a 10 nM concentration, all the AChE inhibitors caused similar effects on behavior, notably increased grooming activity and changes in the frequency of bouts of behavior such as head grooming. Coumaphos caused dose-dependent effects on locomotion as well as grooming behavior, and a 1 μM concentration of coumaphos induced symptoms of malaise such as abdomen grooming and defecation. Biochemical assays confirmed that the four compounds we assayed (coumaphos, aldicarb, chlorpyrifos, and donepezil) or their metabolites acted as AChE inhibitors in bees. Furthermore, we show that transcript expression levels of two honeybee AChE inhibitors were selectively upregulated in the brain and in gut tissues in response to AChE inhibitor exposure. The results of our study imply that the effects of pesticides that rely on this mode of action have subtle yet profound effects on physiological effects on behavior that could lead to reduced survival.

Exposure to Acetylcholinesterase Inhibitors Alters the Physiology and Motor Function of Honeybees

PubMed Central

Williamson, Sally M.; Moffat, Christopher; Gomersall, Martha A. E.; Saranzewa, Nastja; Connolly, Christopher N.; Wright, Geraldine A.

2013-01-01

Cholinergic signaling is fundamental to neuromuscular function in most organisms. Sub-lethal doses of neurotoxic pesticides that target cholinergic signaling can alter the behavior of insects in subtle ways; their influence on non-target organisms may not be readily apparent in simple mortality studies. Beneficial arthropods such as honeybees perform sophisticated behavioral sequences during foraging that, if influenced by pesticides, could impair foraging success and reduce colony health. Here, we investigate the behavioral effects on honeybees of exposure to a selection of pesticides that target cholinergic signaling by inhibiting acetylcholinesterase (AChE). To examine how continued exposure to AChE inhibitors affected motor function, we fed adult foraging worker honeybees sub-lethal concentrations of these compounds in sucrose solution for 24 h. Using an assay for locomotion in bees, we scored walking, stopped, grooming, and upside down behavior continuously for 15 min. At a 10 nM concentration, all the AChE inhibitors caused similar effects on behavior, notably increased grooming activity and changes in the frequency of bouts of behavior such as head grooming. Coumaphos caused dose-dependent effects on locomotion as well as grooming behavior, and a 1 μM concentration of coumaphos induced symptoms of malaise such as abdomen grooming and defecation. Biochemical assays confirmed that the four compounds we assayed (coumaphos, aldicarb, chlorpyrifos, and donepezil) or their metabolites acted as AChE inhibitors in bees. Furthermore, we show that transcript expression levels of two honeybee AChE inhibitors were selectively upregulated in the brain and in gut tissues in response to AChE inhibitor exposure. The results of our study imply that the effects of pesticides that rely on this mode of action have subtle yet profound effects on physiological effects on behavior that could lead to reduced survival. PMID:23386834

Design, evaluation and structure-activity relationship studies of the AChE reactivators against organophosphorus pesticides.

PubMed

Musilek, Kamil; Dolezal, Martin; Gunn-Moore, Frank; Kuca, Kamil

2011-07-01

Organophosphate pesticides (OPPs; e.g. chlorpyrifos, diazinon, paraoxon) are a wide and heterogeneous group of organophosphorus compounds. Their biological activity of inhibiting acetylcholinesterase (AChE) or butyrylcholinesterase (BChE) ranks them as life endangering agents. The necessary treatment after OPP exposure involves the use of parasympatolytics (e.g. atropine), oxime reactivators (e.g. obidoxime), and anticonvulsive drugs (e.g. diazepam). Therefore, the reactivators of AChE are essential compounds in the treatment of OPP intoxications. Commercial AChE reactivators (e.g. pralidoxime, HI-6, obidoxime, trimedoxime, methoxime) were originally developed for other members of the organophosphate family, such as nerve agents (e.g. sarin, soman, tabun, VX). Pralidoxime, HI-6, and methoxime were found to be weak reactivators of OPP-inhibited AChE. Obidoxime and trimedoxime showed satisfactory reactivation against various OPPs with minor toxicity issues. During the last two decades, the treatment of OPP exposure has become more widely discussed because of growing agricultural production, industrialization, and harmful social issues (e.g. suicides). In this review is the summarized design, evaluation, and structure-activity relationship studies of recently produced AChE reactivators. Since pralidoxime, over 300 oximes have been produced or tested against OPP poisoning, and several novel compounds show very promising abilities as comparable (or higher) to commercial oximes. Some of these are highlighted for their further testing of OPP exposure and, additionally, the main structure-activity relationship of AChE reactivators against OPP is discussed. © 2009 Wiley Periodicals, Inc.

Are linear AChR epitopes the real culprit in ocular myasthenia gravis?

PubMed

Wu, Xiaorong; Tüzün, Erdem

2017-02-01

Extraocular muscle weakness occurs in most of the myasthenia gravis (MG) patients and it is often the initial complaint. Approximately 10-20% of MG patients with extraocular muscle weakness display only ocular symptoms and rest of the patients subsequently develop generalized muscle weakness. It is not entirely clear why some MG patients develop only ocular symptoms and why extraocular muscle weakness almost always precedes generalized muscle weakness. These facts are often explained by increased susceptibility of extraocular muscles due to their reduced endplate safety factor and lower complement inhibitor expression. Findings of a recently developed animal model of ocular MG suggest that additional factors might be in play. While immunization of HLA transgenic and wild-type (WT) mice with the native acetylcholine receptor (AChR) pentamer carrying conformational epitopes generates severe generalized muscle weakness, immunization of the same mouse strains with recombinant unfolded AChR subunits containing linear epitopes induces ptosis with or without mild generalized muscle weakness. Notably, immunization of mice with deficient T helper cell-mediated antigen presentation with recombinant AChR subunits or whole native AChR pentamer also induces ocular symptoms, AChR-reactive B cells and AChR antibodies. Based on these findings, we hypothesize that ocular symptoms observed in the earlier stages of MG might be triggered by linear and non-conformational AChR epitopes expressed by thymic cells or invading microorganisms. This initial AChR autoimmunity might be managed by T cell-independent and B cell mediated mechanisms yielding low affinity AChR antibodies. These antibodies are putatively capable of inducing muscle weakness only in extraocular muscles which have increased vulnerability due to their inherent biological properties. After this initial attack, as AChR bearing immune complexes form and the immune system gains access to the native AChR expressed by muscle

Lead finding for acetyl cholinesterase inhibitors from natural origin: structure activity relationship and scope.

PubMed

Mukherjee, P K; Satheeshkumar, N; Venkatesh, P; Venkatesh, M

2011-03-01

Acetylcholinesterase (AChE) inhibitors are considered as promising therapeutic agents for the treatment of several neurological disorders such as Alzheimer's disease (AD), senile dementia, ataxia and myasthenia gravis. There are only few synthetic medicines with adverse effects, available for treatment of cognitive dysfunction and memory loss associated with these diseases. A variety of plants has been reported to possess AChE inhibitory activity and so may be relevant to the treatment of neurodegenerative disorders such as AD. Hence, developing potential AChE inhibitors from botanicals is the need of the day. This review will cover some of the promising acetylcholinesterase inhibitors isolated from plants with proven in vitro and in vivo activities with concern to their structure activity relationship.

Template-based de novo design for type II kinase inhibitors and its extented application to acetylcholinesterase inhibitors.

PubMed

Su, Bo-Han; Huang, Yi-Syuan; Chang, Chia-Yun; Tu, Yi-Shu; Tseng, Yufeng J

2013-10-31

There is a compelling need to discover type II inhibitors targeting the unique DFG-out inactive kinase conformation since they are likely to possess greater potency and selectivity relative to traditional type I inhibitors. Using a known inhibitor, such as a currently available and approved drug or inhibitor, as a template to design new drugs via computational de novo design is helpful when working with known ligand-receptor interactions. This study proposes a new template-based de novo design protocol to discover new inhibitors that preserve and also optimize the binding interactions of the type II kinase template. First, sorafenib (Nexavar) and nilotinib (Tasigna), two type II inhibitors with different ligand-receptor interactions, were selected as the template compounds. The five-step protocol can reassemble each drug from a large fragment library. Our procedure demonstrates that the selected template compounds can be successfully reassembled while the key ligand-receptor interactions are preserved. Furthermore, to demonstrate that the algorithm is able to construct more potent compounds, we considered kinase inhibitors and other protein dataset, acetylcholinesterase (AChE) inhibitors. The de novo optimization was initiated using a template compound possessing a less than optimal activity from a series of aminoisoquinoline and TAK-285 inhibiting type II kinases, and E2020 derivatives inhibiting AChE respectively. Three compounds with greater potency than the template compound were discovered that were also included in the original congeneric series. This template-based lead optimization protocol with the fragment library can help to design compounds with preferred binding interactions of known inhibitors automatically and further optimize the compounds in the binding pockets.

A selective molecularly imprinted polymer for immobilization of acetylcholinesterase (AChE): an active enzyme targeted and efficient method.

PubMed

Demirci, Gökhan; Doğaç, Yasemin İspirli; Teke, Mustafa

2015-11-01

In the present study, we immobilized acetylcholinesterase (AChE) enzyme onto acetylcholine removed imprinted polymer and acetylcholine containing polymer. First, the polymers were produced with acetylcholine, substrate of AChE, by dispersion polymerization. Then, the enzyme was immobilized onto the polymers by using two different methods: In the first method (method A), acetylcholine was removed from the polymer, and then AChE was immobilized onto this polymer (acetylcholine removed imprinted polymer). In the second method (method B), AChE was immobilized onto acetylcholine containing polymer by affinity. In method A, enzyme-specific species (binding sites) occurred by removing acetylcholine from the polymer. The immobilized AChE reached 240% relative specific activity comparison with free AChE because the active enzyme molecules bounded onto the polymer. Transmission electron microscopy results were taken before and after immobilization of AChE for the assessment of morphological structure of polymer. Also, the experiments, which include optimum temperature (25-65 °C), optimum pH (3-10), thermal stability (4-70 °C), kinetic parameters, operational stability and reusability, were performed to determine the characteristic of the immobilized AChE. Copyright © 2015 John Wiley & Sons, Ltd.

A Novel Application of Multiscale Entropy in Electroencephalography to Predict the Efficacy of Acetylcholinesterase Inhibitor in Alzheimer's Disease

PubMed Central

Tsai, Ping-Huang; Liu, Fang-Chun; Tsao, Jenho; Wang, Yung-Hung; Lo, Men-Tzung

2015-01-01

Alzheimer's disease (AD) is the most common form of dementia. According to one hypothesis, AD is caused by the reduced synthesis of the neurotransmitter acetylcholine. Therefore, acetylcholinesterase (AChE) inhibitors are considered to be an effective therapy. For clinicians, however, AChE inhibitors are not a predictable treatment for individual patients. We aimed to disclose the difference by biosignal processing. In this study, we used multiscale entropy (MSE) analysis, which can disclose the embedded information in different time scales, in electroencephalography (EEG), in an attempt to predict the efficacy of AChE inhibitors. Seventeen newly diagnosed AD patients were enrolled, with an initial minimental state examination (MMSE) score of 18.8 ± 4.5. After 12 months of AChE inhibitor therapy, 7 patients were responsive and 10 patients were nonresponsive. The major difference between these two groups is Slope 2 (MSE6 to 20). The area below the receiver operating characteristic (ROC) curve of Slope 2 is 0.871 (95% CI = 0.69–1). The sensitivity is 85.7% and the specificity is 60%, whereas the cut-off value of Slope 2 is −0.024. Therefore, MSE analysis of EEG signals, especially Slope 2, provides a potential tool for predicting the efficacy of AChE inhibitors prior to therapy. PMID:26120358

Synthesis and discovery of highly functionalized mono- and bis-spiro-pyrrolidines as potent cholinesterase enzyme inhibitors.

PubMed

Kia, Yalda; Osman, Hasnah; Suresh Kumar, Raju; Basiri, Alireza; Murugaiyah, Vikneswaran

2014-04-01

Novel mono and bis spiropyrrolidine derivatives were synthesized via an efficient ionic liquid mediated, 1,3-dipolar cycloaddition methodology and evaluated in vitro for their AChE and BChE inhibitory activities in search for potent cholinesterase enzyme inhibitors. Most of the synthesized compounds displayed remarkable AChE inhibitory activities with IC50 values ranging from 1.68 to 21.85 μM, wherein compounds 8d and 8j were found to be most active inhibitors against AChE and BChE with IC50 values of 1.68 and 2.75 μM, respectively. Molecular modeling simulation on Torpedo californica AChE and human BChE receptors, showed good correlation between IC50 values and binding interaction template of the most active inhibitors docked into the active site of their relevant enzymes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Identification of molecular descriptors for design of novel Isoalloxazine derivatives as potential Acetylcholinesterase inhibitors against Alzheimer's disease.

PubMed

Gurung, Arun Bahadur; Aguan, Kripamoy; Mitra, Sivaprasad; Bhattacharjee, Atanu

2017-06-01

In Alzheimer's disease (AD), the level of Acetylcholine (ACh) neurotransmitter is reduced. Since Acetylcholinesterase (AChE) cleaves ACh, inhibitors of AChE are very much sought after for AD treatment. The side effects of current inhibitors necessitate development of newer AChE inhibitors. Isoalloxazine derivatives have proved to be promising (AChE) inhibitors. However, their structure-activity relationship studies have not been reported till date. In the present work, various quantitative structure-activity relationship (QSAR) building methods such as multiple linear regression (MLR), partial least squares ,and principal component regression were employed to derive 3D-QSAR models using steric and electrostatic field descriptors. Statistically significant model was obtained using MLR coupled with stepwise selection method having r 2  = .9405, cross validated r 2 (q 2 ) = .6683, and a high predictability (pred_r 2  = .6206 and standard error, pred_r 2 se = .2491). Steric and electrostatic contribution plot revealed three electrostatic fields E_496, E_386 and E_577 and one steric field S_60 contributing towards biological activity. A ligand-based 3D-pharmacophore model was generated consisting of eight pharmacophore features. Isoalloxazine derivatives were docked against human AChE, which revealed critical residues implicated in hydrogen bonds as well as hydrophobic interactions. The binding modes of docked complexes (AChE_IA1 and AChE_IA14) were validated by molecular dynamics simulation which showed their stable trajectories in terms of root mean square deviation and molecular mechanics/Poisson-Boltzmann surface area binding free energy analysis revealed key residues contributing significantly to overall binding energy. The present study may be useful in the design of more potent Isoalloxazine derivatives as AChE inhibitors.

Investigation of melamine derived quaternary as ammonium salt potential shale inhibitor

NASA Astrophysics Data System (ADS)

Yu, Hongjiang; Hu, Weimin; Guo, Gang; Huang, Lei; Li, Lili; Gu, Xuefan; Zhang, Zhifang; Zhang, Jie; Chen, Gang

2017-06-01

Melamine, sodium chloroacetate and sodium hydroxide were used as raw materials to synthesize a kind of neutral quaternary ammonium salt (NQAS) as potential clay swelling inhibitor and water-based drilling fluid additive, and the reaction conditions were screened based on the linear expansion rate of bentonite. The inhibitive properties of NQASs were investigated by various methods, including montmorillonite (MMT) linear expansion test, mud ball immersing test, particle distribution measurement, thermogravimetric analysis and scanning electron microscopy etc. The results indicate that NQAS can inhibit expansion and dispersion of clay in water effectively. At the same condition, the bentonite linear expansion rate in NQAS-6 solution is much lower than those of others, and the hydration expansion degree of the mud ball in 0.5% NQAS-6 solution is appreciably weaker than the control test. The compatibility test indicates NQAS-6 could be compatible with the conventional additives in water-based drilling fluids, and the temperature resistance of modified starch was improved effectively. Meanwhile, the inhibitive mechanism was discussed through the particle distribution measurement.

Comparative study on short- and long-term behavioral consequences of organophosphate exposure: relationship to AChE mRNA expression.

PubMed

López-Granero, Caridad; Cardona, Diana; Giménez, Estela; Lozano, Rafael; Barril, José; Aschner, Michael; Sánchez-Santed, Fernando; Cañadas, Fernando

2014-01-01

Organophosphates (OPs) affect behavior by inhibiting acetylcholinesterase (AChE). While the cognitive short-term effects may be directly attributed to this inhibition, the mechanisms that underlie OP's long-term cognitive effects remain controversial and poorly understood. Accordingly, two experiments were designed to assess the effects of OPs on cognition, and to ascertain whether both the short- and long-term effects of are AChE-dependent. A single subcutaneous dose of 250 mg/kg chlorpyrifos (CPF), 1.5mg/kg diisopropylphosphorofluoridate (DFP) or 15 mg/kg parathion (PTN) was administered to male Wistar rats. Spatial learning was evaluated 72 h or 23 weeks after exposure, and impulsive choice was tested at 10 and 30 weeks following OPs administration (experiment 1 and 2, respectively). Brain soluble and membrane-bound AChE activity, synaptic AChE-S mRNA, read-through AChE-R mRNA and brain acylpeptide hydrolase (APH) activity (as alternative non-cholinergic target) were analyzed upon completion of the behavioral testing (17 and 37 weeks after OPs exposure). Both short- and long-term CPF treatment caused statistically significant effects on spatial learning, while PTN treatment led only to statistically significant short-term effects. Neither CPF, DFP nor PTN affected the long-term impulsivity response. Long-term exposure to CPF and DFP significantly decreased AChE-S and AChE-R mRNA, while in the PTN treated group only AChE-S mRNA levels were decreased. However, after long-term OP exposure, soluble and membrane-bound AChE activity was indistinguishable from controls. Finally, no changes were noted in brain APH activity in response to OP treatment. Taken together, this study demonstrates long-term effects of OPs on AChE-S and AChE-R mRNA in the absence of changes in AChE soluble and membrane-bound activity. Thus, changes in AChE mRNA expression imply non-catalytic properties of the AChE enzyme. Copyright © 2013 Elsevier Inc. All rights reserved.

Anti-Alzheimers activity and molecular mechanism of albumin-derived peptides against AChE and BChE.

PubMed

Yu, Zhipeng; Wu, Sijia; Zhao, Wenzhu; Ding, Long; Fan, Yue; Shiuan, David; Liu, Jingbo; Chen, Feng

2018-02-21

Alzheimer's disease (AD) is a global health issue affecting millions of elderly people worldwide. The aim of the present study was to identify novel anti-AD peptides isolated from albumin. Anti-AD activities of the peptides were evaluated via inhibitory activities on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Furthermore, the potential molecular mechanisms of the KLPGF/AChE were investigated by CDOCKER of Discovery studio 2017. The results revealed that peptide KLPGF could effectively inhibit AChE with an inhibition rate of 61.23% at a concentration of 50 μg mL -1 . In addition, the peptide KLPGF came in contact with acylation sites and peripheral anion sites of AChE. The present study demonstrates that the peptide KLPGF could become a potential functional food intervention in AD.

High-performance liquid chromatography-mass spectrometry-based acetylcholinesterase assay for the screening of inhibitors in natural extracts.

PubMed

de Jong, Camiel F; Derks, Rico J E; Bruyneel, Ben; Niessen, Wilfried; Irth, Hubertus

2006-04-21

The present paper describes a High-performance liquid chromatography-mass spectrometry (LC-MS) methodology for the screening of acetylcholinesterase (AChE) inhibitors in natural extracts. AChE activity of sample components is monitored by a post-column biochemical assay that is based on the separate, sequential mixing of AChE and acetylcholine, respectively, with the HPLC eluate. AChE inhibitors are detected by measuring a decrease of product formation using electrospray MS. Ammonium bicarbonate was used as buffer in order to achieve optimum compatibility between biochemical assay and MS detection conditions. The assay is robust and stable for over 13 h and compares favourably with other AChE assays in terms of stability and sensitivity. IC(50) values of 9-aminoacridine, galanthamine, gallamine, (-)-huperzine A and thioflavin T were determined to be 0.12, 0.38, 6.4, 0.46 and 3.2 microM, respectively. The assay was used to effectively identify an AChE inhibitor present in a crude extract of Narcissus c.v. "Bridal Crown".

Assessing the binding of cholinesterase inhibitors by docking and molecular dynamics studies.

PubMed

Ali, M Rejwan; Sadoqi, Mostafa; Møller, Simon G; Boutajangout, Allal; Mezei, Mihaly

2017-09-01

In this report we assessed by docking and molecular dynamics the binding mechanisms of three FDA-approved Alzheimer drugs, inhibitors of the enzyme acetylcholinesterase (AChE): donepezil, galantamine and rivastigmine. Dockings by the softwares Autodock-Vina, PatchDock and Plant reproduced the docked conformations of the inhibitor-enzyme complexes within 2Å of RMSD of the X-ray structure. Free-energy scores show strong affinity of the inhibitors for the enzyme binding pocket. Three independent Molecular Dynamics simulation runs indicated general stability of donepezil, galantamine and rivastigmine in their respective enzyme binding pocket (also referred to as gorge) as well as the tendency to form hydrogen bonds with the water molecules. The binding of rivastigmine in the Torpedo California AChE binding pocket is interesting as it eventually undergoes carbamylation and breaks apart according to the X-ray structure of the complex. Similarity search in the ZINC database and targeted docking on the gorge region of the AChE enzyme gave new putative inhibitor molecules with high predicted binding affinity, suitable for potential biophysical and biological assessments. Copyright © 2017 Elsevier Inc. All rights reserved.

Synthesis and study of thiocarbonate derivatives of choline as potential inhibitors of acetylcholinesterase.

PubMed

Boyle, N A; Talesa, V; Giovannini, E; Rosi, G; Norton, S J

1997-09-12

Fourteen alkyl and aryl thiocarbonate derivatives of choline were synthesized and studied as potential inhibitors of acetylcholinesterase (AChE). Twelve of the compounds inhibited AChEs derived from calf forebrain, human red blood cells, and octopus brain ranging from low to moderately high inhibition potency. The concentration of each inhibitory compound giving 50% inhibition of enzyme activity (IC50 values, which ranged from 1 x 10(-2) to 8 x 10(-7) M) was determined and is reported; inhibitor constants (Ki values) for the most inhibitory compounds, (1-pentylthiocarbonyl)choline chloride and (1-heptylthiocarbonyl)choline chloride, were calculated from kinetic data and are also reported. The inhibitors are competitive with substrate, and they are not hydrolyzed by the AChE activities. Certain of these new compounds may provide direction for the development of new drugs that have anticholinesterase activity and may be used for the treatment of Alzheimer's disease.

Novel 16-substituted bifunctional derivatives of huperzine B: multifunctional cholinesterase inhibitors

PubMed Central

Shi, Yu-fang; Zhang, Hai-yan; Wang, Wei; Fu, Yan; Xia, Yu; Tang, Xi-can; Bai, Dong-lu; He, Xu-chang

2009-01-01

Aim: To design novel bifunctional derivatives of huperzine B (HupB) based on the concept of dual binding site of acetylcholinesterase (AChE) and evaluate their pharmacological activities for seeking new drug candidates against Alzheimer's disease (AD). Methods: Novel 16-substituted bifunctional derivatives of HupB were synthesized through chemical reactions. The inhibitory activities of the derivatives toward AChE and butyrylcholinesterase (BuChE) were determined in vitro by modified Ellman's method. Cell viability was quantified by the reduction of MTT. Results: A new preparative method was developed for the generation of 16-substituted derivatives of HupB, and pharmacological trials indicated that the derivatives were multifunctional cholinesterase inhibitors targeting both AChE and BuChE. Among the derivatives tested, 9c, 9e, 9f, and 9i were 480 to 1360 times more potent as AChE inhibitors and 370 to 1560 times more potent as BuChE inhibitors than the parent HupB. Further preliminary pharmacological trials of derivatives 9c and 9i were performed, including examining the mechanism of AChE inhibition, the substrate kinetics of the enzyme inhibition, and protection against hydrogen peroxide (H2O2)-induced cytotoxicity in PC12 cells. Conclusion: Preliminary pharmacological evaluation indicated that 16-substituted derivatives of HupB, particularly 9c and 9i, would be potentially valuable new drug candidates for AD therapy, and further exploration is needed to evaluate their pharmacological and clinical efficacies. PMID:19578388

Assessing the reactivation efficacy of hydroxylamine anion towards VX-inhibited AChE: a computational study.

PubMed

Khan, Md Abdul Shafeeuulla; Ganguly, Bishwajit

2012-05-01

Oximate anions are used as potential reactivating agents for OP-inhibited AChE because of they possess enhanced nucleophilic reactivity due to the α-effect. We have demonstrated the process of reactivating the VX-AChE adduct with formoximate and hydroxylamine anions by applying the DFT approach at the B3LYP/6-311 G(d,p) level of theory. The calculated results suggest that the hydroxylamine anion is more efficient than the formoximate anion at reactivating VX-inhibited AChE. The reaction of formoximate anion and the VX-AChE adduct is a three-step process, while the reaction of hydroxylamine anion with the VX-AChE adduct seems to be a two-step process. The rate-determining step in the process is the initial attack on the VX of the VX-AChE adduct by the nucleophile. The subsequent steps are exergonic in nature. The potential energy surface (PES) for the reaction of the VX-AChE adduct with hydroxylamine anion reveals that the reactivation process is facilitated by the lower free energy of activation (by a factor of 1.7 kcal mol(-1)) than that of the formoximate anion at the B3LYP/6-311 G(d,p) level of theory. The higher free energy of activation for the reverse reactivation reaction between hydroxylamine anion and the VX-serine adduct further suggests that the hydroxylamine anion is a very good antidote agent for the reactivation process. The activation barriers calculated in solvent using the polarizable continuum model (PCM) for the reactivation of the VX-AChE adduct with hydroxylamine anion were also found to be low. The calculated results suggest that V-series compounds can be more toxic than G-series compounds, which is in accord with earlier experimental observations.

Geissoschizine methyl ether, a corynanthean-type indole alkaloid from Uncaria rhynchophylla as a potential acetylcholinesterase inhibitor.

PubMed

Yang, Zhong-Duo; Duan, Dong-Zhu; Du, Juan; Yang, Ming-Jun; Li, Shuo; Yao, Xiao-Jun

2012-01-01

Geissoschizine methyl ether (1), a newly discovered strong acetylcholinesterase (AChE) inhibitor, along with six weakly active alkaloids, vallesiachotamine (2), hisuteine (3), hirsutine (4), isorhynchophylline (5), cisocorynoxeine (6) and corynoxeine (7) have been isolated from Uncaria rhynchophylla. Geissoschizine methyl ether (1) inhibited 50% of AChE activity at concentrations of 3.7 ± 0.3 µg mL(-1) while the IC(50) value of physostigmine as a standard was 0.013 ± 0.002 µg mL(-1). The mode of AChE inhibition by 1 was reversible and non-competitive. In addition, molecular modelling was performed to explore the binding mode of inhibitor 1 at the active site of AChE.

New pyridine derivatives as inhibitors of acetylcholinesterase and amyloid aggregation.

PubMed

Pandolfi, Fabiana; De Vita, Daniela; Bortolami, Martina; Coluccia, Antonio; Di Santo, Roberto; Costi, Roberta; Andrisano, Vincenza; Alabiso, Francesco; Bergamini, Christian; Fato, Romana; Bartolini, Manuela; Scipione, Luigi

2017-12-01

A new series of pyridine derivatives with carbamic or amidic function has been designed and synthesized to act as cholinesterase inhibitors. The synthesized compounds were tested toward EeAChE and hAChE and toward eqBChE and hBChE. The carbamate 8 was the most potent hAChE inhibitor (IC 50  = 0.153 ± 0.016 μM) while the carbamate 11 was the most potent inhibitor of hBChE (IC 50  = 0.828 ± 0.067 μM). A molecular docking study indicated that the carbamate 8 was able to bind AChE by interacting with both CAS and PAS, in agreement with the mixed inhibition mechanism. Furthermore, the carbamates 8, 9 and 11 were able to inhibit Aβ 42 self-aggregation and possessed quite low toxicity against human astrocytoma T67 and HeLa cell lines, being the carbamate 8 the less toxic compound on both cell lines. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Evaluating Fmoc-amino acids as selective inhibitors of butyrylcholinesterase

PubMed Central

Gonzalez, Jeannette; Ramirez, Jennifer

2018-01-01

Cholinesterases are involved in neuronal signal transduction, and perturbation of function has been implicated in diseases, such as Alzheimer’s and Huntington’s disease. For the two major classes of cholinesterases, such as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), previous studies reported BChE activity is elevated in patients with Alzheimer’s disease, while AChE levels remain the same or decrease. Thus, the development of potent and specific inhibitors of BChE have received much attention as a potential therapeutic in the alleviation of neurodegenerative diseases. In this study, we evaluated amino acid analogs as selective inhibitors of BChE. Amino acid analogs bearing a 9-fluorenylmethyloxycarbonyl (Fmoc) group were tested, as the Fmoc group has structural resemblance to previously described inhibitors. We identified leucine, lysine, and tryptophan analogs bearing the Fmoc group as selective inhibitors of BChE. The Fmoc group contributed to inhibition, as analogs bearing a carboxybenzyl group showed ~tenfold higher values for the inhibition constant (KI value). Inclusion of a t-butoxycarbonyl on the side chain of Fmoc tryptophan led to an eightfold lower KI value compared to Fmoc tryptophan alone suggesting that modifications of the amino acid side chains may be designed to create inhibitors with higher affinity. Our results identify Fmoc-amino acids as a scaffold upon which to design BChE-specific inhibitors and provide the foundation for further experimental and computational studies to dissect the interactions that contribute to inhibitor binding. PMID:27522651

Evaluating Fmoc-amino acids as selective inhibitors of butyrylcholinesterase.

PubMed

Gonzalez, Jeannette; Ramirez, Jennifer; Schwans, Jason P

2016-12-01

Cholinesterases are involved in neuronal signal transduction, and perturbation of function has been implicated in diseases, such as Alzheimer's and Huntington's disease. For the two major classes of cholinesterases, such as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), previous studies reported BChE activity is elevated in patients with Alzheimer's disease, while AChE levels remain the same or decrease. Thus, the development of potent and specific inhibitors of BChE have received much attention as a potential therapeutic in the alleviation of neurodegenerative diseases. In this study, we evaluated amino acid analogs as selective inhibitors of BChE. Amino acid analogs bearing a 9-fluorenylmethyloxycarbonyl (Fmoc) group were tested, as the Fmoc group has structural resemblance to previously described inhibitors. We identified leucine, lysine, and tryptophan analogs bearing the Fmoc group as selective inhibitors of BChE. The Fmoc group contributed to inhibition, as analogs bearing a carboxybenzyl group showed ~tenfold higher values for the inhibition constant (K I value). Inclusion of a t-butoxycarbonyl on the side chain of Fmoc tryptophan led to an eightfold lower K I value compared to Fmoc tryptophan alone suggesting that modifications of the amino acid side chains may be designed to create inhibitors with higher affinity. Our results identify Fmoc-amino acids as a scaffold upon which to design BChE-specific inhibitors and provide the foundation for further experimental and computational studies to dissect the interactions that contribute to inhibitor binding.

Selectivity of antagonists for the Cys-loop native receptors for ACh, 5-HT and GABA in guinea-pig myenteric neurons.

PubMed

Juárez, E H; Ochoa-Cortés, F; Miranda-Morales, M; Espinosa-Luna, R; Montaño, L M; Barajas-López, C

2014-01-01

The three most common Cys-loop receptors expressed by myenteric neurons are nACh, 5-HT3 and GABAA . To investigate the function of these proteins researchers have used channel inhibitors such as hexamethonium (antagonist of nACh receptors), ondansetron (antagonist of 5-HT3 receptors), picrotoxin and bicuculline (both antagonists of GABAA receptors). The aim of this study was to investigate the specificity of these inhibitors on Cys-loop receptors of primary cultured neurons obtained from the guinea-pig small intestine. The whole-cell configuration of the patch clamp techniques was used to record membrane currents induced by ACh (IACh ), 5-HT (I5-HT ) and GABA (IGABA ) in the absence and the presence of various concentrations of hexamethonium, ondansetron, picrotoxin or bicuculline. The three Cys-loop receptors present in enteric neurons are expressed independently and they do not cross-desensitized. Hexamethonium inhibited IACh without affecting I5-HT and IGABA . Ondansetron inhibited I5-HT and also IACh but did not affect IGABA . Picrotoxin and bicuculline inhibited I5-HT , IACh and IGABA with different potency, being the lowest potency on 5-HT3 receptors. All these inhibitory effects were concentration dependent and reversible. Our observations showed that except for hexamethonium, all other inhibitors used here show different degrees of selectivity, which has to be considered when these antagonists are used in experimental studies aimed to investigate the functions of these receptors. In particular, in tissues expressing nACh receptors because these are the targets of all other inhibitors used here. The low potency of picrotoxin and bicuculline to inhibit 5-HT3 receptors suggests that these receptors are heteromeric proteins. © 2013 John Wiley & Sons Ltd.

Toxicological and biochemical characterizations of AChE in phosalone-susceptible and resistant populations of the common pistachio psyllid, Agonoscena pistaciae

PubMed Central

Alizadeh, Ali; Talebi-Jahromi, Khalil; Hosseininaveh, Vahid; Ghadamyari, Mohammad

2014-01-01

Abstract The toxicological and biochemical characteristics of acetylcholinesterases (AChE) in nine populations of the common pistachio psyllid, Agonoscena pistaciae Burckhardt and Lauterer (Hemiptera: Psyllidae), were investigated in Kerman Province, Iran. Nine A. pistaciae populations were collected from pistachio orchards, Pistacia vera L. (Sapindales: Anacardiaceae), located in Rafsanjan, Anar, Bam, Kerman, Shahrbabak, Herat, Sirjan, Pariz, and Paghaleh regions of Kerman province. The previous bioassay results showed these populations were susceptible or resistant to phosalone, and the Rafsanjan population was most resistant, with a resistance ratio of 11.3. The specific activity of AChE in the Rafsanjan population was significantly higher than in the susceptible population (Bam). The affinity ( KM ) and hydrolyzing efficiency ( Vmax ) of AChE on acetylthiocholine iodide, butyrylthiocholine iodide, and propionylthiocholine odide as artificial substrates were clearly lower in the Bam population than that in the Rafsanjan population. These results indicated that the AChE of the Rafsanjan population had lower affinity to these substrates than that of the susceptible population. The higher Vmax value in the Rafsanjan population compared to the susceptible population suggests a possible over expression of AChE in the Rafsanjan population. The in vitro inhibitory effect of several organophosphates and carbamates on AChE of the Rafsanjan and Bam populations was determined. Based on I50, the results showed that the ratios of AChE insensitivity of the resistant to susceptible populations were 23 and 21.7-fold to monocrotophos and phosphamidon, respectively. Whereas, the insensitivity ratios for Rafsanjan population were 0.86, 0.8, 0.78, 0.46, and 0.43 for carbaryl, eserine, propoxur, m-tolyl methyl carbamate, and carbofuran, respectively, suggesting negatively correlated sensitivity to organophosphate-insensitive AChE. Therefore, AChE from the Rafsanjan population showed

Molecular modeling and structural analysis of nAChR variants uncovers the mechanism of resistance to snake toxins.

PubMed

Gunasekaran, D; Sridhar, J; Suryanarayanan, V; Manimaran, N C; Singh, Sanjeev Kumar

2017-06-01

Nicotinic acetylcholine receptors (nAChRs) are neuromuscular proteins responsible for muscle contraction upon binding with chemical stimulant acetylcholine (ACh). The α-neurotoxins of snake mimic the structure of ACh and attacks nAChRs, which block the flow of ACh and leads to numbness and paralysis. The toxin-binding site of alpha subunit in the nAChRs is highly conserved throughout chordate lineages with few exceptions in resistance organisms. In this study, we have analyzed the sequence and structures of toxin-binding/resistant nAChRs and their interaction stability with toxins through molecular docking and molecular dynamics simulation (MDS). We have reported the potential glycosylation residues within the toxin-binding cleft adding sugar moieties through N-linked glycosylation in resistant organisms. Residue variations at key positions alter the secondary structure of binding cleft, which might interfere with toxin binding and it could be one of the possible explanations for the resistance to snake venoms. Analysis of nAChR-α-neurotoxin complexes has confirmed the key interacting residues. In addition, drastic variation in the binding stability of Mongoose nAChR-α-Bungarotoxin (α-BTX) and human nAChR-α-BTX complexes were found at specific phase of MDS. Our findings suggest that specific mutations in the binding site of toxin are potentially preventing the formation of stable complex of receptor-toxin, which might lead to mechanism of resistance. This in silico study on the binding cleft of nAChR and the findings of interacting residues will assist in designing potential inhibitors as therapeutic targets.

Bivalent ligands derived from Huperzine A as acetylcholinesterase inhibitors.

PubMed

Haviv, H; Wong, D M; Silman, I; Sussman, J L

2007-01-01

The naturally occurring alkaloid Huperzine A (HupA) is an acetylcholinesterase (AChE) inhibitor that has been used for centuries as a Chinese folk medicine in the context of its source plant Huperzia Serrata. The potency and relative safety of HupA rendered it a promising drug for the ameliorative treatment of Alzheimer's disease (AD) vis-à-vis the "cholinergic hypothesis" that attributes the cognitive decrements associated with AD to acetylcholine deficiency in the brain. However, recent evidence supports a neuroprotective role for HupA, suggesting that it could act as more than a mere palliative. Biochemical and crystallographic studies of AChE revealed two potential binding sites in the active-site gorge of AChE, one of which, the "peripheral anionic site" at the mouth of the gorge, was implicated in promoting aggregation of the beta amyloid (Abeta) peptide responsible for the neurodegenerative process in AD. This feature of AChE facilitated the development of dual-site binding HupA-based bivalent ligands, in hopes of concomitantly increasing AChE inhibition potency by utilizing the "chelate effect", and protecting neurons from Abeta toxicity. Crystal structures of AChE allowed detailed modeling and docking studies that were instrumental in enhancing the understanding of underlying principles of bivalent inhibitor-enzyme dynamics. This monograph reviews two categories of HupA-based bivalent ligands, in which HupA and HupA fragments serve as building blocks, with a focus on the recently solved crystallographic structures of Torpedo californica AChE in complex with such bifunctional agents. The advantages and drawbacks of such structured-based drug design, as well as species differences, are highlighted and discussed.

Mechanisms of flow and ACh-induced dilation in rat soleus arterioles are altered by hindlimb unweighting

NASA Technical Reports Server (NTRS)

Schrage, William G.; Woodman, Christopher R.; Laughlin, M. Harold

2002-01-01

The purpose of this study was to test the hypothesis that endothelium-dependent dilation (flow-induced dilation and ACh-induced dilation) in rat soleus muscle arterioles is impaired by hindlimb unweighting (HLU). Male Sprague-Dawley rats (approximately 300 g) were exposed to HLU or weight-bearing control (Con) conditions for 14 days. Soleus first-order (1A) and second-order (2A) arterioles were isolated, cannulated, and exposed to step increases in luminal flow at constant pressure. Flow-induced dilation was not impaired by HLU in 1A or 2A arterioles. The cyclooxygenase inhibitor indomethacin (Indo; 50 microM) did not alter flow-induced dilation in 1As or 2As. Inhibition of nitric oxide synthase (NOS) with N(omega)-nitro-L-arginine (L-NNA; 300 microM) reduced flow-induced dilation by 65-70% in Con and HLU 1As. In contrast, L-NNA abolished flow-induced dilation in 2As from Con rats but had no effect in HLU 2As. Combined treatment with L-NNA + Indo reduced tone in 1As and 2As from Con rats, but flow-induced dilation in the presence of L-NNA + Indo was not different from responses without inhibitors in either Con or HLU 1As or 2As. HLU also did not impair ACh-induced dilation (10(-9)-10(-4) M) in soleus 2As. L-NNA reduced ACh-induced dilation by approximately 40% in Con 2As but abolished dilation in HLU 2As. Indo did not alter ACh-induced dilation in Con or HLU 2As, whereas combined treatment with L-NNA + Indo abolished ACh-induced dilation in 2As from both groups. We conclude that flow-induced dilation (1As and 2As) was preserved after 2 wk HLU, but HLU decreased the contribution of NOS in mediating flow-induced dilation and increased the contribution of a NOS- and cyclooxygenase-independent mechanism (possibly endothelium-derived hyperpolarizing factor). In soleus 2As, ACh-induced dilation was preserved after 2-wk HLU but the contribution of NOS in mediating ACh-induced dilation was increased.

Acetylcholine ameliorates endoplasmic reticulum stress in endothelial cells after hypoxia/reoxygenation via M3 AChR-AMPK signaling.

PubMed

Bi, Xueyuan; He, Xi; Xu, Man; Zhao, Ming; Yu, Xiaojiang; Lu, Xingzhu; Zang, Weijin

2015-08-03

Endoplasmic reticulum (ER) stress is associated with various cardiovascular diseases. However, its pathophysiological relevance and the underlying mechanisms in the context of hypoxia/reoxygenation (H/R) in endothelial cells are not fully understood. Previous findings have suggested that acetylcholine (ACh), the major vagal nerve neurotransmitter, protected against cardiomyocyte injury by activating AMP-activated protein kinase (AMPK). This study investigated the role of ER stress in endothelial cells during H/R and explored the beneficial effects of ACh. Our results showed that H/R triggered ER stress and apoptosis in endothelial cells, evidenced by the elevation of glucose-regulated protein 78, cleaved caspase-12 and C/EBP homologous protein expression. ACh significantly decreased ER stress and terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end labeling positive cells and restored ER ultrastructural changes induced by H/R, possibly via protein kinase-like ER kinase and inositol-requiring kinase 1 pathways. Additionally, 4-diphenylacetoxy-N-methylpiperidine methiodide, a type-3 muscarinic ACh receptor (M3 AChR) inhibitor, abolished ACh-mediated increase in AMPK phosphorylation during H/R. Furthermore, M3 AChR or AMPK siRNA abrogated the ACh-elicited the attenuation of ER stress in endothelial cells, indicating that the salutary effects of ACh were likely mediated by M3 AChR-AMPK signaling. Overall, ACh activated AMPK through M3 AChR, thereby inhibited H/R-induced ER stress and apoptosis in endothelial cells. We have suggested for the first time that AMPK may function as an essential intermediate step between M3 AChR stimulation and inhibition of ER stress-associated apoptotic pathway during H/R, which may help to develop novel therapeutic approaches targeting ER stress to prevent or alleviate ischemia/reperfusion injury.

Design and synthesis of dual inhibitors of acetylcholinesterase and serotonin transporter targeting potential agents for Alzheimer's disease.

PubMed

Kogen, Hiroshi; Toda, Narihiro; Tago, Keiko; Marumoto, Shinji; Takami, Kazuko; Ori, Mayuko; Yamada, Naho; Koyama, Kazuo; Naruto, Shunji; Abe, Kazumi; Yamazaki, Reina; Hara, Takao; Aoyagi, Atsushi; Abe, Yasuyuki; Kaneko, Tsugio

2002-10-03

Highly efficient acetylcholinesterase (AChE) and serotonin transporter (SERT) dual inhibitors, (S)-4 and (R)-13 were designed and synthesized on the basis of the hypothetical model of AChE active site. Both compounds showed potent inhibitory activities against AChE and SERT. [structure: see text

Preparation, in vitro screening and molecular modelling of symmetrical 4-tert-butylpyridinium cholinesterase inhibitors--analogues of SAD-128.

PubMed

Musilek, Kamil; Roder, Jan; Komloova, Marketa; Holas, Ondrej; Hrabinova, Martina; Pohanka, Miroslav; Dohnal, Vlastimil; Opletalova, Veronika; Kuca, Kamil; Jung, Young-Sik

2011-01-01

Carbamate inhibitors (e.g., pyridostimine bromide) are used as a pre-exposure treatment for the prevention of organophosphorus poisoning. They work by blocking acetylcholinesterase's (AChE) native function and thus protect AChE against irreversible inhibition by organophosphorus compounds. However, carbamate inhibitors are known for many undesirable side-effects related to the carbamylation of AChE. In this Letter, 19 analogues of SAD-128 were prepared and evaluated as cholinesterase inhibitors. The screening results showed promising inhibitory ability of four compounds better to used standards (pralidoxime, obidoxime, BW284c51, ethopropazine, SAD-128). Four most promising compounds were selected for further molecular docking studies. The SAR was stated from obtained data. The former receptor studies were reported and discussed. The further in vivo studies were recommended in the view of OP pre-exposure treatment. Copyright © 2010 Elsevier Ltd. All rights reserved.

Syntheses of coumarin-tacrine hybrids as dual-site acetylcholinesterase inhibitors and their activity against butylcholinesterase, Aβ aggregation, and β-secretase.

PubMed

Sun, Qi; Peng, Da-Yong; Yang, Sheng-Gang; Zhu, Xiao-Lei; Yang, Wen-Chao; Yang, Guang-Fu

2014-09-01

Exploring small-molecule acetylcholinesterase (AChE) inhibitors to slow the breakdown of acetylcholine (Ach) represents the mainstream direction for Alzheimer's disease (AD) therapy. As the first acetylcholinesterase inhibitor approved for the clinical treatment of AD, tacrine has been widely used as a pharmacophore to design hybrid compounds in order to combine its potent AChE inhibition with other multi-target profiles. In present study, a series of novel tacrine-coumarin hybrids were designed, synthesized and evaluated as potent dual-site AChE inhibitors. Moreover, compound 1g was identified as the most potent candidate with about 2-fold higher potency (Ki=16.7nM) against human AChE and about 2-fold lower potency (Ki=16.1nM) against BChE than tacrine (Ki=35.7nM for AChE, Ki=8.7nM for BChE), respectively. In addition, some of the tacrine-coumarin hybrids showed simultaneous inhibitory effects against both Aβ aggregation and β-secretase. We therefore conclude that tacrine-coumarin hybrid is an interesting multifunctional lead for the AD drug discovery. Copyright © 2014 Elsevier Ltd. All rights reserved.

Inhibitors of Acetylcholinesterase and Butyrylcholinesterase Meet Immunity

PubMed Central

Pohanka, Miroslav

2014-01-01

Acetylcholinesterase (AChE) inhibitors are widely used for the symptomatic treatment of Alzheimer’s disease and other dementias. More recent use is for myasthenia gravis. Many of these inhibitors interact with the second known cholinesterase, butyrylcholinesterase (BChE). Further, evidence shows that acetylcholine plays a role in suppression of cytokine release through a “cholinergic anti-inflammatory pathway” which raises questions about the role of these inhibitors in the immune system. This review covers research and discussion of the role of the inhibitors in modulating the immune response using as examples the commonly available drugs, donepezil, galantamine, huperzine, neostigmine and pyridostigmine. Major attention is given to the cholinergic anti-inflammatory pathway, a well-described link between the central nervous system and terminal effector cells in the immune system. PMID:24893223

A new continuous fluorometric assay for acetylcholinesterase activity and inhibitor screening with emissive core-shell silica particles containing tetraphenylethylene fluorophore.

PubMed

Shen, Xiang; Liang, Fuxin; Zhang, Guanxin; Zhang, Deqing

2012-05-07

Emissive core-shell silica particles with tetraphenylethylene moieties were prepared and characterized. Fluorescence quenching was observed for the silica particles upon addition of compound 2 (Dabcyl-ACh). This was attributed to the electrostatic interaction between the silica particles and 2 and the resulting photoinduced energy transfer between them. After incubation with AChE, the fluorescence intensity started to increase. The fluorescence enhancement became more significant when the concentration of AChE was higher. The reaction kinetic parameters for AChE were successfully estimated with the silica particles and 2. These results reveal that the ensemble of the silica particles and 2 can be utilized for AChE assay. Moreover, the fluorescence spectra of the ensemble of the silica particles and 2 containing AChE were also measured after further addition of either neostigmine or tacrine which are typical inhibitors of AChE. The results manifest that the ensemble of the emissive silica particles and 2 is also useful for screening the inhibitors of AChE.

A comparison of the efficacy of newly developed reversible inhibitors of acetylcholinesterase with commonly used pyridostigmine as pharmacological pre-treatment of soman-poisoned mice.

PubMed

Kassa, Jiri; Musilek, Kamil; Koomlova, Marketa; Bajgar, Jiri

2012-04-01

The ability of three newly developed reversible inhibitors of acetylcholinesterase (AChE) (K298, K344 and K474) and currently available carbamate pyridostigmine to increase the resistance of mice against soman and the efficacy of antidotal treatment of soman-poisoned mice was compared. Neither pyridostigmine nor new reversible inhibitors of AChE were able to increase the LD(50) value of soman. Thus, the pharmacological pre-treatment with pyridostigmine or newly synthesized inhibitors of AChE was not able to protect mice against soman-induced lethal acute toxicity. The pharmacological pre-treatment with pyridostigmine alone or with K474 was able to slightly increase the efficacy of antidotal treatment (the oxime HI-6 in combination with atropine) of soman-poisoned mice, but the increase in the efficacy of antidotal treatment was not significant. The other newly developed reversible inhibitors of AChF (K298, K344) were completely ineffective. These findings demonstrate that pharmacological pre-treatment of soman-poisoned mice with tested reversible inhibitors of AChF is not promising. © 2011 The Authors. Basic & Clinical Pharmacology & Toxicology © 2011 Nordic Pharmacological Society.

Novel eugenol derivatives: Potent acetylcholinesterase and carbonic anhydrase inhibitors.

PubMed

Topal, Fevzi; Gulcin, Ilhami; Dastan, Arif; Guney, Murat

2017-01-01

Eugenol was used as starting material to obtain some phenolic compounds. The synthesis of these phenolic compounds was performed in a two-step procedure. The structures of the formed products (novel eugenol derivatives 1-6) have been determined on the basis of NMR spectroscopy and other spectroscopic methods. The compounds were tested in terms of carbonic anhydrase (CA) inhibition potency. Carbonic anhydrases (CAs, EC 4.2.1.1) are metalloenzymes, which catalyse the reaction between carbon dioxide (CO 2 ) and water (H 2 O), to generate bicarbonate (HCO 3 - ) and protons (H + ). CO 2 , HCO 3 - and H + are essential molecules and ions for many important physiologic processes occurring in all living organisms. Acetylcholinesterase (AChE, E.C.3.1.1.7) is found in high concentrations in the red blood cells and brain. Novel eugenol derivatives (1-6) were tested for the inhibition of two cytosolic CA isoforms I, and II (hCA I, and II) and AChE. These compounds demonstrated effective inhibitory profiles with Ki values in ranging of 113.48-738.69nM against hCA I, 92.35-530.81nM against hCA II, and 90.10-379.57nM against AChE, respectively. On the other hand, acetazolamide clinically used as CA inhibitor, shoed Ki value of 594.11nM against hCA I, and 120.68nM against hCA II, respectively. Also, AChE was inhibited by tacrine as an AChE inhibitor at the 71.18nM level. Copyright © 2016 Elsevier B.V. All rights reserved.

Preparation, in vitro screening and molecular modelling of symmetrical bis-quinolinium cholinesterase inhibitors--implications for early myasthenia gravis treatment.

PubMed

Komloova, Marketa; Musilek, Kamil; Horova, Anna; Holas, Ondrej; Dohnal, Vlastimil; Gunn-Moore, Frank; Kuca, Kamil

2011-04-15

This paper describes the preparation and in vitro evaluation of 18 newly prepared bis-quinolinium inhibitors on human recombinant acetylcholinesterase (AChE) and human plasmatic butyrylcholinesterase (BChE). Their inhibitory (IC(50)) and was compared to the chosen standards ambenonium dichloride, edrophonium chloride, BW284c51 and ethopropazine hydrochloride. One novel compound was found to be a promising inhibitor of hAChE (in nM range) and was better than edrophonium chloride or BW284c51, but was worse than ambenonium chloride. This compound also showed selectivity towards hAChE and it was confirmed as a non-competitive inhibitor of hAChE by kinetic analysis. A molecular modelling study further confirmed its binding to the peripheral active site of hAChE via apparent π-π or π-cationic interactions. Copyright © 2011 Elsevier Ltd. All rights reserved.

Oximes: Inhibitors of Human Recombinant Acetylcholinesterase. A Structure-Activity Relationship (SAR) Study

PubMed Central

Sepsova, Vendula; Karasova, Jana Zdarova; Korabecny, Jan; Dolezal, Rafael; Zemek, Filip; Bennion, Brian J.; Kuca, Kamil

2013-01-01

Acetylcholinesterase (AChE) reactivators were developed for the treatment of organophosphate intoxication. Standard care involves the use of anticonvulsants (e.g., diazepam), parasympatolytics (e.g., atropine) and oximes that restore AChE activity. However, oximes also bind to the active site of AChE, simultaneously acting as reversible inhibitors. The goal of the present study is to determine how oxime structure influences the inhibition of human recombinant AChE (hrAChE). Therefore, 24 structurally different oximes were tested and the results compared to the previous eel AChE (EeAChE) experiments. Structural factors that were tested included the number of pyridinium rings, the length and structural features of the linker, and the number and position of the oxime group on the pyridinium ring. PMID:23959117

Planarian cholinesterase: in vitro characterization of an evolutionarily ancient enzyme to study organophosphorus pesticide toxicity and reactivation.

PubMed

Hagstrom, Danielle; Hirokawa, Hideto; Zhang, Limin; Radic, Zoran; Taylor, Palmer; Collins, Eva-Maria S

2017-08-01

The freshwater planarian Dugesia japonica has recently emerged as an animal model for developmental neurotoxicology and found to be sensitive to organophosphorus (OP) pesticides. While previous activity staining of D. japonica, which possess a discrete cholinergic nervous system, has shown acylthiocholine catalysis, it is unknown whether this is accomplished through an acetylcholinesterase (AChE), butyrylcholinesterase (BChE), or a hybrid esterase and how OP exposure affects esterase activity. Here, we show that the majority of D. japonica cholinesterase (DjChE) activity departs from conventional AChE and BChE classifications. Inhibition by classic protonable amine and quaternary reversible inhibitors (ethopropazine, donepezil, tacrine, edrophonium, BW284c51, propidium) shows that DjChE is far less sensitive to these inhibitors than human AChE, suggesting discrete differences in active center and peripheral site recognition and structures. Additionally, we find that different OPs (chlorpyrifos oxon, paraoxon, dichlorvos, diazinon oxon, malaoxon) and carbamylating agents (carbaryl, neostigmine, physostigmine, pyridostigmine) differentially inhibit DjChE activity in vitro. DjChE was most sensitive to diazinon oxon and neostigmine and least sensitive to malaoxon and carbaryl. Diazinon oxon-inhibited DjChE could be reactivated by the quaternary oxime, pralidoxime (2-PAM), and the zwitterionic oxime, RS194B, with RS194B being significantly more potent. Sodium fluoride (NaF) reactivates OP-DjChE faster than 2-PAM. As one of the most ancient true cholinesterases, DjChE provides insight into the evolution of a hybrid enzyme before the separation into distinct AChE and BChE enzymes found in higher vertebrates. The sensitivity of DjChE to OPs and capacity for reactivation validate the use of planarians for OP toxicology studies.

Syntheses and characterization of novel oxoisoaporphine derivatives as dual inhibitors for cholinesterases and amyloid beta aggregation.

PubMed

Li, Yan-Ping; Ning, Fang-Xian; Yang, Meng-Bi; Li, Yong-Cheng; Nie, Min-Hua; Ou, Tian-Miao; Tan, Jia-Heng; Huang, Shi-Liang; Li, Ding; Gu, Lian-Quan; Huang, Zhi-Shu

2011-05-01

A series of 3-substituted (5c-5f, 6c-6f) and 4-substituted (10a-10g) oxoisoaporphine derivatives were synthesized. It was found that all these synthetic compounds had IC50 values at micro or nano molar range for cholinesterase inhibition, and most of them could inhibit amyloid β (Aβ) self-induced aggregation with inhibition ratio from 31.8% to 57.6%. The structure-activity relationship studies revealed that the derivatives with higher selectivity on AChE also showed better inhibition on Aβ self-induced aggregation. The results from cell toxicity study indicated that most quaternary methiodide salts had higher IC50 values than the corresponding non-quaternary compounds. This study provided potentially important information for further development of oxoisoaporphine derivatives as lead compounds for the treatment of Alzheimer's disease. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Multipotent MAO and cholinesterase inhibitors for the treatment of Alzheimer's disease: synthesis, pharmacological analysis and molecular modeling of heterocyclic substituted alkyl and cycloalkyl propargyl amine.

PubMed

Samadi, Abdelouahid; de los Ríos, Cristóbal; Bolea, Irene; Chioua, Mourad; Iriepa, Isabel; Moraleda, Ignacio; Bartolini, Manuela; Andrisano, Vincenza; Gálvez, Enrique; Valderas, Carolina; Unzeta, Mercedes; Marco-Contelles, José

2012-06-01

The synthesis, pharmacological evaluation and molecular modeling of heterocyclic substituted alkyl and cycloalkyl propargyl amines 1-7 of type I, and 9-12 of type II, designed as multipotent inhibitors able to simultaneously inhibit monoamine oxidases (MAO-A/B) as well as cholinesterase (AChE/BuChE) enzymes, as potential drugs for the treatment of Alzheimer's disease, are described. Indole derivatives 1-7 of type I are well known MAO inhibitors whose capacity to inhibit AChE and BuChE was here investigated for the first time. As a result, compound 7 was identified as a MAO-B inhibitor (IC(50) = 31 ± 2 nM) and a moderately selective eqBuChE inhibitor (IC(50) = 4.7 ± 0.2 μM). Conversely, the new and readily available 5-amino-7-(prop-2-yn-1-yl)-6,7,8,9-tetrahydropyrido[2,3-b][1,6]naphthyridine derivatives 9-13 of type II are poor MAO inhibitors, but showed AChE selective inhibition, compound 12 being the most attractive as it acts as a non-competitive inhibitor on EeAChE (IC(50) = 25 ± 3 nM, K(i) = 65 nM). The ability of this compound to interact with the AChE peripheral binding site was confirmed by kinetic studies and by molecular modeling investigation. Studies on human ChEs confirmed that 12 is a selective AChE inhibitor with inhibitory potency in the submicromolar range. Moreover, in agreement with its mode of action, 12 was shown to be able to inhibit Aβ aggregation induced by hAChE by 30.6%. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Acetamide Derivatives of Chromen-2-ones as Potent Cholinesterase Inhibitors.

PubMed

Prasad, Suchita; Kumar, Bipul; Kumar, Shiv; Chand, Karam; Kamble, Shashank S; Gautam, Hemant K; Sharma, Sunil K

2017-08-01

Alzheimer's disease (AD), a neurodegenerative disorder, is a serious medical issue worldwide with drastic social consequences. Inhibition of cholinesterase is one of the rational and effective approaches to retard the symptoms of AD and, hence, consistent efforts are being made to develop efficient anti-cholinesterase agents. In pursuit of this, a series of 19 acetamide derivatives of chromen-2-ones were synthesized and evaluated for their acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory potential. All the synthesized compounds exhibited significant anti-AChE and anti-BChE activity, with IC 50 values in the range of 0.24-10.19 μM and 0.64-30.08 μM, respectively, using donepezil hydrochloride as the standard. Out of 19 compounds screened, 3 compounds, viz. 22, 40, and 43, caused 50% inhibition of AChE at 0.24, 0.25, and 0.25 μM, respectively. A kinetic study revealed them to be mixed-type inhibitors, binding with both the CAS and PAS sites of AChE. The above-selected compounds were found to be effective inhibitors of AChE-induced and self-mediated Aβ 1-42 aggregation. ADMET predictions demonstrated that these compounds may possess suitable blood-brain barrier (BBB) permeability. Hemolytic assay results revealed that these compounds did not lyse human RBCs up to a thousand times of their IC 50 value. MTT assays performed for the shortlisted compounds showed them to be negligibly toxic after 24 h of treatment with the SH-SY5Y neuroblastoma cells. These results provide insights for further optimization of the scaffolds for designing the next generation of compounds as lead cholinesterase inhibitors. © 2017 Deutsche Pharmazeutische Gesellschaft.

Arisugacins A and B, novel and selective acetylcholinesterase inhibitors from Penicillium sp. FO-4259. I. Screening, taxonomy, fermentation, isolation and biological activity.

PubMed

Kuno, F; Otoguro, K; Shiomi, K; Iwai, Y; Omura, S

1996-08-01

An in vitro screening method for selective acetylcholinesterase (AChE) inhibitors was established. Inhibitory activity of AChE and butyrylcholinesterase (BuChE) was measured and the culture broths of microorganisms that showed selective inhibition against AChE were characterized. By using this method, a strain producing the novel and selective inhibitors of AChE, arisugacins A and B, was picked out among over seven thousand microorganisms tested. Arisugacins were obtained as white powders from the culture broth together with three known compounds, territrems B and C and cyclopenin that also showed selective inhibition against AChE. Arisugacins and territrems are members of the meroterpenoid compounds. They showed potent inhibitory activities against AChE with IC50 values in range of 1.0 approximately 25.8 nM. Furthermore, they showed greater than 2,000-fold more potent inhibition against AChE than BuChE.

Kinetics and molecular docking studies of loganin, morroniside and 7-O-galloyl-D-sedoheptulose derived from Corni fructus as cholinesterase and β-secretase 1 inhibitors.

PubMed

Bhakta, Himanshu Kumar; Park, Chan Hum; Yokozawa, Takako; Min, Byung-Sun; Jung, Hyun Ah; Choi, Jae Sue

2016-06-01

We evaluated the major active components isolated from Corni Fructus: loganin, morroniside, and 7-O-galloyl-D-sedoheptulose as inhibitors of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and β-site amyloid precursor protein (APP) cleaving enzyme 1 (BACE1) for use in Alzheimer's disease treatment. These compounds exhibited predominant cholinesterase (ChEs) inhibitory effects with IC50 values of 0.33, 3.95, and 10.50 ± 1.16 µM, respectively, for AChE, and 33.02, 37.78, and 87.94 ± 4.66 µM, respectively, for BChE. Kinetics studies revealed that loganin and 7-O-galloyl-D-sedoheptulose inhibited AChE with characteristics typical of mixed inhibitors, while morroniside was found to be a noncompetitive inhibitor against AChE and also exerted mixed BChE inhibitory activities. For BACE1, loganin showed noncompetitive type inhibitory effects, while morroniside and 7-O-galloyl-D-sedoheptulose were found to be mixed inhibitors. Furthermore, these compounds exhibited dose-dependent inhibitory activity with ONOO(-)-mediated protein tyrosine nitration. Molecular docking simulation of these compounds demonstrated negative binding energies for ChEs, and BACE1, indicating high affinity and tighter binding capacity for the active site of the enzyme. Loganin was the most potent inhibitor against both ChEs and BACE1. The data suggest that these compounds together can act as a triple inhibitor of AChE, BChE, and BACE1, providing a preventive and therapeutic strategy for Alzheimer's disease treatment.

Efficient Synthesis and Discovery of Schiff Bases as Potent Cholinesterase Inhibitors.

PubMed

Razik, Basma M Abd; Osman, Hasnah; Ezzat, Mohammed O; Basiri, Alireza; Salhin, Abdussalam; Kia, Yalda; Murugaiyah, Vikneswaran

2016-01-01

The search for new cholinesterase inhibitors is still a promising approach for management of Alzheimer`s disease. Schiff bases are considered as important class of organic compounds, which have wide range of applications including as enzyme inhibitors. In the present study, a new green ionic liquid mediated strategy was developed for convenient synthesis of two series of Schiff bases 3(a-j) and 5(a-j) as potential cholinesterase inhibitors using aromatic aldehydes and primary amines in [bmim]Br. The synthesized compounds were evaluated for their acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory potential by modified Ellman's method. The molecular interactions between the most active compound and the enzyme were analyzed by molecular docking. Among them, 3j displayed higher inhibitory activities than reference drug, galanthamine, with IC50 values of 2.05 and 5.77 µM, for AChE and BChE, respectively. Interestingly, all the compounds except 3b displayed higher BChE inhibitions than galanthamine with IC50 values ranging from 5.77 to 18.52 µM. Molecular docking of compound 3j inside the TcAChE and hBChE completely coincided with the inhibitory activities observed. The compound forms strong hydrogen bonding at the peripheral anionic site of AChE whereas on BChE, it had hydrophobic and mild polar interactions. An efficient and eco-friendly synthetic methodology has been developed to synthesize Schiff bases in a very short reaction time and excellent yields in ionic solvent, whereby the compounds from series 3 showed promising cholinesterase inhibitory activity.

Studies on the interaction of BDE-47 and BDE-209 with acetylcholinesterase (AChE) based on the neurotoxicity through fluorescence, UV-vis spectra, and molecular docking.

PubMed

Wang, Shutao; Wu, Chuan; Liu, Zhisheng; You, Hong

2018-05-01

The neurotoxicity of polybrominated diphenyl ethers (PBDEs) has been of concern. Acetylcholinesterase (AChE) is a critical enzyme in the central and peripheral nervous system related to neurotoxicity. The interaction between BDE-47, BDE-209, and AChE was investigated through fluorescence and UV-vis spectra combined with molecular docking. Both BDE-47 and BDE-209 bound with AChE and changed the microenvironment of some amino acid residues, resulting in a change of AChE conformation. Hydrophobic interaction is the main binding force between BDE-47, BDE-209, and AChE, and electrostatic interaction exists according to the thermodynamic parameters of the interaction between them. A hydrophobic interaction of BDE-47-AChE and BDE-209-AChE has been confirmed through molecular docking to dominate the binding force. The binding constants of BDE-47-AChE and BDE-209-AChE were 4.2 × 10 4 and 4.1 × 10 4  L/mol, respectively, and the lowest binding energies of BDE-47-AChE and BDE-209-AChE were -7.8 and -5.9 kJ/mol, respectively. BDE-47 is more likely to bind with AChE than BED-209. Copyright © 2018 Elsevier B.V. All rights reserved.

Dual functional cholinesterase and MAO inhibitors for the treatment of Alzheimer's disease: synthesis, pharmacological analysis and molecular modeling of homoisoflavonoid derivatives.

PubMed

Wang, Yali; Sun, Yang; Guo, Yueyan; Wang, Zechen; Huang, Ling; Li, Xingshu

2016-01-01

Because of the complexity of Alzheimer's disease (AD), the multi-target-directed ligand (MTDL) strategy is expected to provide superior effects for the treatment of AD, instead of the classic one-drug-one-target strategy. In this context, we focused on the design, synthesis and evaluation of homoisoflavonoid derivatives as dual acetyl cholinesterase (AChE) and monoamine oxidase (MAO-B) inhibitors. Among all the synthesized compounds, compound 10 provided a desired balance of AChE and hMAO-B inhibition activities, with IC50 value of 3.94 and 3.44 μM, respectively. Further studies revealed that compound 10 was a mixed-type inhibitor of AChE and an irreversible inhibitor of hMAO-B, which was also confirmed by molecular modeling studies. Taken together, the data indicated that 10 was a promising dual functional agent for the treatment of AD.

Existence of muscarinic acetylcholine receptor (mAChR) and fibroblast growth factor receptor (FGFR) heteroreceptor complexes and their enhancement of neurite outgrowth in neural hippocampal cultures.

PubMed

Di Liberto, V; Borroto-Escuela, D O; Frinchi, M; Verdi, V; Fuxe, K; Belluardo, N; Mudò, G

2017-02-01

Recently, it was demonstrated that G-protein-coupled receptors (GPCRs) can transactivate tyrosine kinase receptors in absence of their ligands. In this work, driven by the observation that mAChRs and fibroblast growth factor receptors (FGFRs) share signalling pathways and regulation of brain functions, it was decided to explore whether mAChRs activation may transactivate FGFRs and, if so, to characterize the related trophic effects in cultured hippocampal neurons. Oxotremorine-M transactivation of FGFRs and related trophic effects were tested in primary hippocampal neurons. Western blotting and in situ proximity ligation assay (PLA) were used to detect FGFR phosphorylation (pFGFR) levels and M 1 R-FGFR1 heteroreceptor complexes, respectively. Oxotremorine-M, a non-selective mAChRs agonist, was able to transactivate FGFR and this transactivation was blocked by Src inhibitors. Oxotremorine-M treatment produced a significant increase in the primary neurite outgrowth that was blocked by pre-treatment with the pFGFR inhibitor SU5402 and Src inhibitors. This trophic effect was almost similar to that induced by fibroblast growth factor-2 (FGF-2). By using atropine as nonselective mAChRs or pirenzepine as selective antagonist for M 1 receptor (M 1 R) we could show that mAChRs are involved in modulating the pFGFRs. Using PLA, M 1 R-FGFR1 heteroreceptor complexes were identified in the hippocampus and cerebral cortex. The current findings, by showing functional mAChR-FGFR interactions, will contribute to advance the understanding of the mechanisms involved in the actions of cholinergic drugs on neuronal plasticity. Data may help to develop novel therapeutic strategies not only for neurodegenerative diseases but also for depression-induced atrophy of hippocampal neurons. Copyright © 2016 Elsevier B.V. All rights reserved.

Synthesis, cytotoxicity and molecular modelling studies of new phenylcinnamide derivatives as potent inhibitors of cholinesterases.

PubMed

Saeed, Aamer; Mahesar, Parvez Ali; Zaib, Sumera; Khan, Muhammad Siraj; Matin, Abdul; Shahid, Mohammad; Iqbal, Jamshed

2014-05-06

The present study reports the synthesis of cinnamide derivatives and their biological activity as inhibitors of both cholinesterases and anticancer agents. Controlled inhibition of brain acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) may slow neurodegeneration in Alzheimer's diseases (AD). The anticholinesterase activity of phenylcinnamide derivatives was determined against Electric Eel acetylcholinesterase (EeAChE) and horse serum butyrylcholinesterase (hBChE) and some of the compounds appeared as moderately potent inhibitors of EeAChE and hBChE. The compound 3-(2-(Benzyloxy)phenyl)-N-(3,4,5-trimethoxyphenyl)acrylamide (3i) showed maximum activity against EeAChE with an IC50 0.29 ± 0.21 μM whereas 3-(2-chloro-6-nitrophenyl)-N-(3,4,5-trimethoxyphenyl)acrylamide (3k) was proved to be the most potent inhibitor of hBChE having IC50 1.18 ± 1.31 μM. To better understand the enzyme-inhibitor interaction of the most active compounds toward cholinesterases, molecular modelling studies were carried out on high-resolution crystallographic structures. The anticancer effects of synthesized compounds were also evaluated against cancer cell line (lung carcinoma). The compounds may be useful leads for the design of a new class of anticancer drugs for the treatment of cancer and cholinesterase inhibitors for Alzheimer's disease (AD). Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Recent developments in the synthesis of acetylcholinesterase inhibitors.

PubMed

Marco, José L; Carreiras, M Carmo

2003-09-01

The acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activities of a series of pyrano[2,3-b]quinolines (2, 3), [1,8]naphthyridines (5, 6), 4-amino-2,3-diaryl-5,6,7,8-tetrahydrofuro[2,3-b]quinolines (11-13)/ 4-amino-6,7,8,9-tetrahydro-2,3-diphenyl-5H-cyclohepta[e]furo[2,3-b]pyridine (14), 4-amino-5,6,7,8-tetrahydro-2,3-diphenylthieno[2,3-b]quinoline (15)/ 4-amino-6,7,8,9-tetrahydro-2,3-diphenyl-5H-cyclohepta[e]thieno[2,3-b]pyridine (16) are described. These compounds are tacrine analogues that have been prepared from readily available polyfunctionalized ethyl [6-amino-5-cyano-4H-pyran]-3-carboxylates (9, 10), ethyl [6-amino-5-cyanopyridine]-3-carboxylates (7, 8), 2-amino-3-cyano-4,5-diarylfurans (17-19) and 2-amino-3-cyano-4,5-diphenylthiophene (20) via Friedländer condensation with selected ketones. These compounds are competitive and, in a few cases, non-competitive inhibitors for AChE, the most potent being compound (14), though three-fold less active than tacrine. The BuChE inhibitory activity is only significant in compounds 11 and 14, ten-fold less active than tacrine. Furthermore, the products 12 and 13 are selective and moderate AChE inhibitors.

Inactivation of JAK2/STAT3 Signaling Axis and Downregulation of M1 mAChR Cause Cognitive Impairment in klotho Mutant Mice, a Genetic Model of Aging

PubMed Central

Park, Seok-Joo; Shin, Eun-Joo; Min, Sun Seek; An, Jihua; Li, Zhengyi; Hee Chung, Yoon; Hoon Jeong, Ji; Bach, Jae-Hyung; Nah, Seung-Yeol; Kim, Won-Ki; Jang, Choon-Gon; Kim, Yong-Sun; Nabeshima, Yo-ichi; Nabeshima, Toshitaka; Kim, Hyoung-Chun

2013-01-01

We previously reported cognitive dysfunction in klotho mutant mice. In the present study, we further examined novel mechanisms involved in cognitive impairment in these mice. Significantly decreased janus kinase 2 (JAK2) and signal transducer and activator of transcription3 (STAT3) phosphorylation were observed in the hippocampus of klotho mutant mice. A selective decrease in protein expression and binding density of the M1 muscarinic cholinergic receptor (M1 mAChR) was observed in these mice. Cholinergic parameters (ie, acetylcholine (ACh), choline acetyltransferase (ChAT), and acetylcholinesterase (AChE)) and NMDAR-dependent long-term potentiation (LTP) were significantly impaired in klotho mutant mice. McN-A-343 (McN), an M1 mAChR agonist, significantly attenuated these impairments. AG490 (AG), a JAK2 inhibitor, counteracted the attenuating effects of McN, although AG did not significantly alter the McN-induced effect on AChE. Furthermore, AG significantly inhibited the attenuating effects of McN on decreased NMDAR-dependent LTP, protein kinase C βII, p-ERK, p-CREB, BDNF, and p-JAK2/p-STAT3-expression in klotho mutant mice. In addition, k252a, a BDNF receptor tyrosine kinase B (TrkB) inhibitor, significantly counteracted McN effects on decreased ChAT, ACh, and M1 mAChR and p-JAK2/p-STAT3 expression. McN-induced effects on cognitive impairment in klotho mutant mice were consistently counteracted by either AG or k252a. Our results suggest that inactivation of the JAK2/STAT3 signaling axis and M1 mAChR downregulation play a critical role in cognitive impairment observed in klotho mutant mice. PMID:23389690

Potentiation by cholinesterase inhibitors of cholinergic activity in rat isolated stomach and colon.

PubMed

Jarvie, Emma M; Cellek, Selim; Sanger, Gareth J

2008-01-01

Acetylcholinesterase (AChE) inhibitors stimulate gastrointestinal (GI) motility and are potential treatments of conditions associated with inadequate GI motility. The ability of itopride to facilitate neuronally (predominantly cholinergic) mediated contractions of rat isolated stomach, evoked by electrical field stimulation (EFS), has been compared with other cholinesterase inhibitors and with tegaserod, a clinically effective prokinetic and non-selective 5-HT(4) receptor agonist which also facilitates GI cholinergic function. Neostigmine greatly increased EFS-evoked contractions over a narrow concentration range (0.01-1 microM; 754+/-337% facilitation at 1 microM); higher concentrations (1, 3 microM) also increased muscle tension. Donepezil increased EFS-evoked contractions gradually over the full range of concentrations (0.01-10 microM; maximum increase 516+/-20% at 10 microM). Itopride increased the contractions even more gradually, rising to 188+/-84% at 10 microM. The butyrylcholinesterase inhibitor iso-OMPA 0.01-10 microM also increased EFS-evoked contractions, to a maximum of 36+/-5.0% at 10 microM, similar to that caused by tegaserod (35+/-5.2% increase at 1 microM). The effects of tegaserod, but not itopride were inhibited by the 5-HT(4) receptor antagonist SB-204070A 0.3 microM. In rat isolated colon, neostigmine was again the most efficacious, causing a defined maximum increase in EFS-evoked contractions (343+/-82% at 10 microM), without changing muscle tension. Maximum increases caused by donepezil and itopride were, respectively, 57.6+/-20 and 43+/-15% at 10 microM. These data indicate that the abilities of different AChE inhibitors to increase GI cholinergic activity differ markedly. Understanding the reasons is essential if AChE inhibitors are to be optimally developed as GI prokinetics.

A review on cholinesterase inhibitors for Alzheimer's disease.

PubMed

Anand, Preet; Singh, Baldev

2013-04-01

Alzheimer's disease (AD), a progressive neurodegenerative disorder, is characterized by the deficits in the cholinergic system and deposition of beta amyloid (Aβ) in the form of neurofibrillary tangles and amyloid plaques. Since the cholinergic system plays an important role in the regulation of learning and memory processes, it has been targetted for the design of anti-Alzheimer's drugs. Cholinesterase inhibitors enhance cholinergic transmission directly by inhibiting the enzyme acetylcholinesterase (AChE) which hydrolyses acetylcholine. Furthermore, it has been also demonstrated that both acetylcholinesterase and butrylcholinesterase (BuChE) play an important role in Aβ-aggregation during the early stages of senile plaque formation. Therefore, AChE and BuChE inhibition have been documented as critical targets for the effective management of AD by an increase in the availability of acetylcholine in the brain regions and decrease in the Aβ deposition. This review discusses the different classes of cholinesterase inhibitors including tacrine, donepezil, rivastigmine, galantamine, xanthostigmine, para-aminobenzoic acid, coumarin, flavonoid, and pyrrolo-isoxazole analogues developed for the treatment of AD.

Unbinding of fluorinated oxime drug from the AChE gorge in polarizable water: a well-tempered metadynamics study.

PubMed

Pathak, Arup Kumar; Bandyopadhyay, Tusar

2017-02-15

Despite the fact that fluorination makes a drug more lipophilic, the molecular level understanding of protein-fluorinated drug interactions is very poor. Due to their enhanced ability to penetrate the blood brain barrier, they are suitable for reactivation of organophosphorus inactivated acetylcholinesterase (AChE) in the central nervous system. We systematically studied the unbinding of fluorinated obidoxime (FOBI) and non-fluorinated obidoxime (OBI) from the active site gorge of the serine hydrolase AChE in mean field polarizable water by employing all atom molecular dynamics simulations. It is observed that the unbinding process is strongly influenced by cation-π, hydrogen bond (HB) and water bridge interactions. The FOBI drug interacts more strongly with the protein residues than OBI and this is also verified from quantum mechanical calculations. Distinct unbinding pathways for FOBI and OBI are observed as evident from the 1D and 2D potential of mean force of the unbinding profiles. The present study suggests that the FOBI drug is held more firmly in the gorge of AChE in comparison to OBI and may lead to higher reactivation efficiency of the inactivated enzyme.

Photolabeling a Nicotinic Acetylcholine Receptor (nAChR) with an (α4)3(β2)2 nAChR-Selective Positive Allosteric Modulator

PubMed Central

Deba, Farah; Wang, Ze-Jun; Cohen, Jonathan B.

2016-01-01

Positive allosteric modulators (PAMs) of nicotinic acetylcholine (ACh) receptors (nAChRs) have potential clinical applications in the treatment of nicotine dependence and many neuropsychiatric conditions associated with decreased brain cholinergic activity, and 3-(2-chlorophenyl)-5-(5-methyl-1-(piperidin-4-yl)-1H-pyrrazol-4-yl)isoxazole (CMPI) has been identified as a PAM selective for neuronal nAChRs containing the α4 subunit. In this report, we compare CMPI interactions with low-sensitivity (α4)3(β2)2 and high-sensitivity (α4)2(β2)3 nAChRs, and with muscle-type nAChRs. In addition, we use the intrinsic reactivity of [3H]CMPI upon photolysis at 312 nm to identify its binding sites in Torpedo nAChRs. Recording from Xenopus oocytes, we found that CMPI potentiated maximally the responses of (α4)3(β2)2 nAChR to 10 μM ACh (EC10) by 400% and with an EC50 of ∼1 µM. CMPI produced a left shift of the ACh concentration-response curve without altering ACh efficacy. In contrast, CMPI inhibited (∼35% at 10 µM) ACh responses of (α4)2(β2)3 nAChRs and fully inhibited human muscle and Torpedo nAChRs with IC50 values of ∼0.5 µM. Upon irradiation at 312 nm, [3H]CMPI photoincorporated into each Torpedo [(α1)2β1γδ] nAChR subunit. Sequencing of peptide fragments isolated from [3H]CMPI-photolabeled nAChR subunits established photolabeling of amino acids contributing to the ACh binding sites (αTyr190, αTyr198, γTrp55, γTyr111, γTyr117, δTrp57) that was fully inhibitable by agonist and lower-efficiency, state-dependent [3H]CMPI photolabeling within the ion channel. Our results establish that CMPI is a potent potentiator of nAChRs containing an α4:α4 subunit interface, and that its intrinsic photoreactivy makes it of potential use to identify its binding sites in the (α4)3(β2)2 nAChR. PMID:26976945

Natural cholinesterase inhibitors from Myristica cinnamomea King.

PubMed

Abdul Wahab, Siti Mariam; Sivasothy, Yasodha; Liew, Sook Yee; Litaudon, Marc; Mohamad, Jamaludin; Awang, Khalijah

2016-08-01

A new acylphenol, malabaricone E (1) together with the known malabaricones A-C (2-4), maingayones A and B (5 and 6) and maingayic acid B (7) were isolated from the ethyl acetate extract of the fruits of Myristica cinnamomea King. Their structures were determined by 1D and 2D NMR techniques and LCMS-IT-TOF analysis. Compounds 3 (1.84±0.19 and 1.76±0.21μM, respectively) and 4 (1.94±0.27 and 2.80±0.49μM, respectively) were identified as dual inhibitors, with almost equal acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes inhibiting potentials. The Lineweaver-Burk plots of compounds 3 and 4 indicated that they were mixed-mode inhibitors. Based on the molecular docking studies, compounds 3 and 4 interacted with the peripheral anionic site (PAS), the catalytic triad and the oxyanion hole of the AChE. As for the BChE, while compound 3 interacted with the PAS, the catalytic triad and the oxyanion hole, compound 4 only interacted with the catalytic triad and the oxyanion hole. Copyright © 2016 Elsevier Ltd. All rights reserved.

Menthol Alone Upregulates Midbrain nAChRs, Alters nAChR Subtype Stoichiometry, Alters Dopamine Neuron Firing Frequency, and Prevents Nicotine Reward.

PubMed

Henderson, Brandon J; Wall, Teagan R; Henley, Beverley M; Kim, Charlene H; Nichols, Weston A; Moaddel, Ruin; Xiao, Cheng; Lester, Henry A

2016-03-09

Upregulation of β2 subunit-containing (β2*) nicotinic acetylcholine receptors (nAChRs) is implicated in several aspects of nicotine addiction, and menthol cigarette smokers tend to upregulate β2* nAChRs more than nonmenthol cigarette smokers. We investigated the effect of long-term menthol alone on midbrain neurons containing nAChRs. In midbrain dopaminergic (DA) neurons from mice containing fluorescent nAChR subunits, menthol alone increased the number of α4 and α6 nAChR subunits, but this upregulation did not occur in midbrain GABAergic neurons. Thus, chronic menthol produces a cell-type-selective upregulation of α4* nAChRs, complementing that of chronic nicotine alone, which upregulates α4 subunit-containing (α4*) nAChRs in GABAergic but not DA neurons. In mouse brain slices and cultured midbrain neurons, menthol reduced DA neuron firing frequency and altered DA neuron excitability following nAChR activation. Furthermore, menthol exposure before nicotine abolished nicotine reward-related behavior in mice. In neuroblastoma cells transfected with fluorescent nAChR subunits, exposure to 500 nm menthol alone also increased nAChR number and favored the formation of (α4)3(β2)2 nAChRs; this contrasts with the action of nicotine itself, which favors (α4)2(β2)3 nAChRs. Menthol alone also increases the number of α6β2 receptors that exclude the β3 subunit. Thus, menthol stabilizes lower-sensitivity α4* and α6 subunit-containing nAChRs, possibly by acting as a chemical chaperone. The abolition of nicotine reward-related behavior may be mediated through menthol's ability to stabilize lower-sensitivity nAChRs and alter DA neuron excitability. We conclude that menthol is more than a tobacco flavorant: administered alone chronically, it alters midbrain DA neurons of the nicotine reward-related pathway. Copyright © 2016 the authors 0270-6474/16/362957-18$15.00/0.

7-Methoxytacrine-adamantylamine heterodimers as cholinesterase inhibitors in Alzheimer's disease treatment--synthesis, biological evaluation and molecular modeling studies.

PubMed

Spilovska, Katarina; Korabecny, Jan; Kral, Jan; Horova, Anna; Musilek, Kamil; Soukup, Ondrej; Drtinova, Lucie; Gazova, Zuzana; Siposova, Katarina; Kuca, Kamil

2013-02-20

A structural series of 7-MEOTA-adamantylamine thioureas was designed, synthesized and evaluated as inhibitors of human acetylcholinesterase (hAChE) and human butyrylcholinesterase (hBChE). The compounds were prepared based on the multi-target-directed ligand strategy with different linker lengths (n = 2-8) joining the well-known NMDA antagonist adamantine and the hAChE inhibitor 7-methoxytacrine (7-MEOTA). Based on in silico studies, these inhibitors proved dual binding site character capable of simultaneous interaction with the peripheral anionic site (PAS) of hAChE and the catalytic active site (CAS). Clearly, these structural derivatives exhibited very good inhibitory activity towards hBChE resulting in more selective inhibitors of this enzyme. The most potent cholinesterase inhibitor was found to be thiourea analogue 14 (with an IC₅₀ value of 0.47 µM for hAChE and an IC₅₀ value of 0.11 µM for hBChE, respectively). Molecule 14 is a suitable novel lead compound for further evaluation proving that the strategy of dual binding site inhibitors might be a promising direction for development of novel AD drugs.

Rho-kinase inhibitor and nicotinamide adenine dinucleotide phosphate oxidase inhibitor prevent impairment of endothelium-dependent cerebral vasodilation by acute cigarette smoking in rats.

PubMed

Iida, Hiroki; Iida, Mami; Takenaka, Motoyasu; Fukuoka, Naokazu; Dohi, Shuji

2008-06-01

We previously reported that acute cigarette smoking can cause a dysfunction of endothelium-dependent vasodilation in cerebral vessels, and that blocking the angiotensin II (Ang II) type 1 (AT1) receptor with valsartan prevented this impairment. Our aim was to investigate the effects of a Rho-kinase inhibitor (fasudil) and a Nicotinamide Adenine Dinucleotide PHosphate (NADPH) oxidase inhibitor (apocynin) on smoking-induced endothelial dysfunction in cerebral arterioles. In Sprague-Dawley rats, we used a closed cranial window preparation to measure changes in pial vessel diameters following topical acetylcholine (ACh) before smoking. After one-minute smoking, we again examined the arteriolar responses to ACh. Finally, after intravenous fasudil or apocynin pre-treatment we re-examined the vasodilator responses to topical ACh (before and after cigarette smoking). Under control conditions, cerebral arterioles were dose-dependently dilated by topical ACh (10(-6) M and 10(-5) M). One hour after a one-minute smoking (1 mg-nicotine cigarette), 10(-5) M ACh constricted cerebral arterioles. However, one hour after a one-minute smoking, 10(-5) M ACh dilated cerebral pial arteries both in the fasudil pre-treatment and the apocynin pre-treatment groups, responses that were significantly different from those obtained without fasudil or apocynin pre-treatment. Thus, inhibition of Rho-kinase and NADPH oxidase activities may prevent the above smoking-induced impairment of endothelium-dependent vasodilation.

Designing Second Generation Anti-Alzheimer Compounds as Inhibitors of Human Acetylcholinesterase: Computational Screening of Synthetic Molecules and Dietary Phytochemicals

PubMed Central

Amat-ur-Rasool, Hafsa; Ahmed, Mehboob

2015-01-01

Alzheimer's disease (AD), a big cause of memory loss, is a progressive neurodegenerative disorder. The disease leads to irreversible loss of neurons that result in reduced level of acetylcholine neurotransmitter (ACh). The reduction of ACh level impairs brain functioning. One aspect of AD therapy is to maintain ACh level up to a safe limit, by blocking acetylcholinesterase (AChE), an enzyme that is naturally responsible for its degradation. This research presents an in-silico screening and designing of hAChE inhibitors as potential anti-Alzheimer drugs. Molecular docking results of the database retrieved (synthetic chemicals and dietary phytochemicals) and self-drawn ligands were compared with Food and Drug Administration (FDA) approved drugs against AD as controls. Furthermore, computational ADME studies were performed on the hits to assess their safety. Human AChE was found to be most approptiate target site as compared to commonly used Torpedo AChE. Among the tested dietry phytochemicals, berberastine, berberine, yohimbine, sanguinarine, elemol and naringenin are the worth mentioning phytochemicals as potential anti-Alzheimer drugs The synthetic leads were mostly dual binding site inhibitors with two binding subunits linked by a carbon chain i.e. second generation AD drugs. Fifteen new heterodimers were designed that were computationally more efficient inhibitors than previously reported compounds. Using computational methods, compounds present in online chemical databases can be screened to design more efficient and safer drugs against cognitive symptoms of AD. PMID:26325402

Designing Second Generation Anti-Alzheimer Compounds as Inhibitors of Human Acetylcholinesterase: Computational Screening of Synthetic Molecules and Dietary Phytochemicals.

PubMed

Amat-Ur-Rasool, Hafsa; Ahmed, Mehboob

2015-01-01

Alzheimer's disease (AD), a big cause of memory loss, is a progressive neurodegenerative disorder. The disease leads to irreversible loss of neurons that result in reduced level of acetylcholine neurotransmitter (ACh). The reduction of ACh level impairs brain functioning. One aspect of AD therapy is to maintain ACh level up to a safe limit, by blocking acetylcholinesterase (AChE), an enzyme that is naturally responsible for its degradation. This research presents an in-silico screening and designing of hAChE inhibitors as potential anti-Alzheimer drugs. Molecular docking results of the database retrieved (synthetic chemicals and dietary phytochemicals) and self-drawn ligands were compared with Food and Drug Administration (FDA) approved drugs against AD as controls. Furthermore, computational ADME studies were performed on the hits to assess their safety. Human AChE was found to be most approptiate target site as compared to commonly used Torpedo AChE. Among the tested dietry phytochemicals, berberastine, berberine, yohimbine, sanguinarine, elemol and naringenin are the worth mentioning phytochemicals as potential anti-Alzheimer drugs The synthetic leads were mostly dual binding site inhibitors with two binding subunits linked by a carbon chain i.e. second generation AD drugs. Fifteen new heterodimers were designed that were computationally more efficient inhibitors than previously reported compounds. Using computational methods, compounds present in online chemical databases can be screened to design more efficient and safer drugs against cognitive symptoms of AD.

Amino derivatives of glycyrrhetinic acid as potential inhibitors of cholinesterases.

PubMed

Schwarz, Stefan; Lucas, Susana Dias; Sommerwerk, Sven; Csuk, René

2014-07-01

The development of remedies against the Alzheimer's disease (AD) is one of the biggest challenges in medicinal chemistry nowadays. Although not completely understood, there are several strategies fighting this disease or at least bringing some relief. During the progress of AD, the level of acetylcholine (ACh) decreases; hence, a therapy using inhibitors should be of some benefit to the patients. Drugs presently used for the treatment of AD inhibit the two ACh controlling enzymes, acetylcholinesterase as well as butyrylcholinesterase; hence, the design of selective inhibitors is called for. Glycyrrhetinic acid seems to be an interesting starting point for the development of selective inhibitors. Although its glycon, glycyrrhetinic acid is known for being an AChE activator, several derivatives, altered in position C-3 and C-30, exhibited remarkable inhibition constants in micro-molar range. Furthermore, five representative compounds were subjected to three more enzyme assays (on carbonic anhydrase II, papain and the lipase from Candida antarctica) to gain information about the selectivity of the compounds in comparison to other enzymes. In addition, photometric sulforhodamine B assays using murine embryonic fibroblasts (NiH 3T3) were performed to study the cytotoxicity of these compounds. Two derivatives, bearing either a 1,3-diaminopropyl or a 1H-benzotriazolyl residue, showed a BChE selective inhibition in the single-digit micro-molar range without being cytotoxic up to 30μM. In silico molecular docking studies on the active sites of AChE and BChE were performed to gain a molecular insight into the mode of action of these compounds and to explain the pronounced selectivity for BChE. Copyright © 2014 Elsevier Ltd. All rights reserved.

Design, synthesis and evaluation of novel tacrine-coumarin hybrids as multifunctional cholinesterase inhibitors against Alzheimer's disease.

PubMed

Xie, Sai-Sai; Wang, Xiao-Bing; Li, Jiang-Yan; Yang, Lei; Kong, Ling-Yi

2013-06-01

A series of tacrine-coumarin hybrids (8a-t) were designed, synthesized and evaluated as multifunctional cholinesterase (ChE) inhibitors against Alzheimer's disease (AD). The screening results showed that most of them exhibited a significant ability to inhibit ChE and self-induced β-amyloid (Aβ) aggregation, and to act as metal chelators. Especially, 8f displayed the greatest ability to inhibit acetylcholinesterase (AChE, IC50 = 0.092 μM) and Aβ aggregation (67.8%, 20 μM). It was also a good butyrylcholinesterase inhibitor (BuChE, IC50 = 0.234 μM) and metal chelator. Besides, kinetic and molecular modeling studies indicated that 8f was a mixed-type inhibitor, binding simultaneously to active, peripheral and mid-gorge sites of AChE. These results suggested that 8f might be an excellent multifunctional agent for AD treatment. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Novel tacrine/acridine anticholinesterase inhibitors with piperazine and thiourea linkers.

PubMed

Hamulakova, Slavka; Imrich, Jan; Janovec, Ladislav; Kristian, Pavol; Danihel, Ivan; Holas, Ondrej; Pohanka, Miroslav; Böhm, Stanislav; Kozurkova, Maria; Kuca, Kamil

2014-09-01

A new series of substituted tacrine/acridine and tacrine/tacrine dimers with aliphatic or alkylene-thiourea linkers was synthesized and the potential of these compounds as novel human acetylcholinesterase (hAChE) and human butyrylcholinesterase (hBChE) inhibitors with nanomolar inhibition activity was evaluated. The most potent AChE inhibitor was found to be homodimeric tacrine derivative 14a, which demonstrated an IC50 value of 2 nM; this value indicates an activity rate which is 250-times higher than that of tacrine 1 and 7500-times higher than 7-MEOTA 15, the compounds which were used as standards in the study. IC50 values of derivatives 1, 9, 10, 14b and 15 were compared with the dissociation constants of the enzyme-inhibitor complex, Ki1, and the enzyme-substrate-inhibitor complex, Ki2, for. A dual binding site is presumed for the synthesized compounds which possess two tacrines or tacrine and acridine as terminal moieties show evidence of dual site binding. DFT calculations of theoretical desolvation free energies, ΔΔGtheor, and docking studies elucidate these suggestions in more detail. Copyright © 2014 Elsevier B.V. All rights reserved.

Menthol Alone Upregulates Midbrain nAChRs, Alters nAChR Subtype Stoichiometry, Alters Dopamine Neuron Firing Frequency, and Prevents Nicotine Reward

PubMed Central

Henderson, Brandon J.; Wall, Teagan R.; Henley, Beverley M.; Kim, Charlene H.; Nichols, Weston A.; Moaddel, Ruin; Xiao, Cheng

2016-01-01

Upregulation of β2 subunit-containing (β2*) nicotinic acetylcholine receptors (nAChRs) is implicated in several aspects of nicotine addiction, and menthol cigarette smokers tend to upregulate β2* nAChRs more than nonmenthol cigarette smokers. We investigated the effect of long-term menthol alone on midbrain neurons containing nAChRs. In midbrain dopaminergic (DA) neurons from mice containing fluorescent nAChR subunits, menthol alone increased the number of α4 and α6 nAChR subunits, but this upregulation did not occur in midbrain GABAergic neurons. Thus, chronic menthol produces a cell-type-selective upregulation of α4* nAChRs, complementing that of chronic nicotine alone, which upregulates α4 subunit-containing (α4*) nAChRs in GABAergic but not DA neurons. In mouse brain slices and cultured midbrain neurons, menthol reduced DA neuron firing frequency and altered DA neuron excitability following nAChR activation. Furthermore, menthol exposure before nicotine abolished nicotine reward-related behavior in mice. In neuroblastoma cells transfected with fluorescent nAChR subunits, exposure to 500 nm menthol alone also increased nAChR number and favored the formation of (α4)3(β2)2 nAChRs; this contrasts with the action of nicotine itself, which favors (α4)2(β2)3 nAChRs. Menthol alone also increases the number of α6β2 receptors that exclude the β3 subunit. Thus, menthol stabilizes lower-sensitivity α4* and α6 subunit-containing nAChRs, possibly by acting as a chemical chaperone. The abolition of nicotine reward-related behavior may be mediated through menthol's ability to stabilize lower-sensitivity nAChRs and alter DA neuron excitability. We conclude that menthol is more than a tobacco flavorant: administered alone chronically, it alters midbrain DA neurons of the nicotine reward-related pathway. SIGNIFICANCE STATEMENT Menthol, the most popular flavorant for tobacco products, has been considered simply a benign flavor additive. However, as we show here

Effects of EGCG and Chlorpyrifos on the Mortality, AChE and GSH of Adult Zebrafish: Independent and Combination

NASA Astrophysics Data System (ADS)

Zhang, Rong; Zhang, Jian; Gao, Qian; Guo, Nichun

2018-01-01

Chlorpyrifos is a neurotoxic agent and also causes oxidative stress in the body. EGCG is a typical strong antioxidant and has been reported to be neuroprotective. Our study investigated the mortality, the activity of acetylcholinesterase (AChE) in the brain and glutathione (GSH) in the liver of the adult Zebrafish in present of Chlorpyrifos and EGCG independent and combination. The results indicated that after the addition of EGCG, the mortality of zebrafish induced by Chlorpyrifos was reduced and the activity of AChE and glutathione (GSH) inhibited by Chlorpyrifos in zebrafish was significantly increased, which demonstrated that EGCG inhibited the toxicity Chlorpyrifos to zebrafish. The inhibition was dependent on the concentration of EGCG and Chlorpyrifos, which was not shown a gradual change trend but a complex situation.

Ionic liquid mediated synthesis of mono- and bis-spirooxindole-hexahydropyrrolidines as cholinesterase inhibitors and their molecular docking studies.

PubMed

Kia, Yalda; Osman, Hasnah; Kumar, Raju Suresh; Basiri, Alireza; Murugaiyah, Vikneswaran

2014-02-15

One pot, three-component reaction of 1-acryloyl-3,5-bisarylmethylidenepiperidin-4-ones with isatin and sarcosine in molar ratios of 1:1:1 and 1:2:2 furnished to mono- and bis-spiropyrrolidine heterocyclic hybrids comprising functionalized piperidine, pyrrolidine and oxindole structural motifs. Both mono and bis-spiropyrrolidines displayed good inhibitory activity against acetylcholinesterase (AChE) with IC₅₀ values of 2.36-9.43 μM. For butyrylcholinesterase (BChE), mono-cycloadducts in series 8 with IC₅₀ values of lower than 10 μM displayed better inhibitory activities than their bis-cycloadduct analogs in series 9 with IC₅₀ values of 7.44-19.12 μM. The cycloadducts 9j and 8e were found to be the most potent AChE and BChE inhibitors with IC₅₀ values of 2.35 and 3.21 μM, respectively. Compound 9j was found to be competitive inhibitor of AChE while compound 8e was a mixed-mode inhibitor of BChE with calculated Ki values of 2.01 and 6.76 μM, respectively. Molecular docking on Torpedo californica AChE and human BChE showed good correlation between IC₅₀ values and free binding energy values of the synthesized compounds docked into the active site of the enzymes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Pyridostigmine but not 3,4-diaminopyridine exacerbates ACh receptor loss and myasthenia induced in mice by muscle-specific kinase autoantibody.

PubMed

Morsch, Marco; Reddel, Stephen W; Ghazanfari, Nazanin; Toyka, Klaus V; Phillips, William D

2013-05-15

In myasthenia gravis, the neuromuscular junction is impaired by the antibody-mediated loss of postsynaptic acetylcholine receptors (AChRs). Muscle weakness can be improved upon treatment with pyridostigmine, a cholinesterase inhibitor, or with 3,4-diaminopyridine, which increases the release of ACh quanta. The clinical efficacy of pyridostigmine is in doubt for certain forms of myasthenia. Here we formally examined the effects of these compounds in the antibody-induced mouse model of anti-muscle-specific kinase (MuSK) myasthenia gravis. Mice received 14 daily injections of IgG from patients with anti-MuSK myasthenia gravis. This caused reductions in postsynaptic AChR densities and in endplate potential amplitudes. Systemic delivery of pyridostigmine at therapeutically relevant levels from days 7 to 14 exacerbated the anti-MuSK-induced structural alterations and functional impairment at motor endplates in the diaphragm muscle. No such effect of pyridostigmine was found in mice receiving control human IgG. Mice receiving smaller amounts of MuSK autoantibodies did not display overt weakness, but 9 days of pyridostigmine treatment precipitated generalised muscle weakness. In contrast, one week of treatment with 3,4-diaminopyridine enhanced neuromuscular transmission in the diaphragm muscle. Both pyridostigmine and 3,4-diaminopyridine increase ACh in the synaptic cleft yet only pyridostigmine potentiated the anti-MuSK-induced decline in endplate ACh receptor density. These results thus suggest that ongoing pyridostigmine treatment potentiates anti-MuSK-induced AChR loss by prolonging the activity of ACh in the synaptic cleft.

Preparation and in vitro screening of symmetrical bis-isoquinolinium cholinesterase inhibitors bearing various connecting linkage--implications for early Myasthenia gravis treatment.

PubMed

Musilek, Kamil; Komloova, Marketa; Holas, Ondrej; Hrabinova, Martina; Pohanka, Miroslav; Dohnal, Vlastimil; Nachon, Florian; Dolezal, Martin; Kuca, Kamil

2011-02-01

Inhibitors of acetylcholinesterase are compounds widely used in the treatment of various diseases, such as Alzheimer's disease, glaucoma and Myasthenia gravis (MG). Compounds used in the therapy of MG posses a positive charge in the molecule to ensure peripheral effect of action and minimal blood-brain barrier penetration. The most prescribed carbamate inhibitors are however known for many severe side effects related to the carbamylation of AChE. This paper describes preparation and in vitro evaluation of 20 newly prepared bis-isoquinolinium inhibitors of potential concern for MG. The newly prepared compounds were evaluated in vitro on human recombinant AChE and human plasmatic butyrylcholinesterase (BChE). Their inhibitory ability was expressed as IC50 and compared to chosen standards ambenonium dichloride, edrophonium chloride, BW284c51 and ethopropazine hydrochloride. Three novel compounds presented promising inhibition (in nM range) of both enzymes in vitro better or similar to edrophonium and BW284c51, but worse to ambenonium. The novel inhibitors did not present higher selectivity toward AChE or BChE. The kinetic assay confirmed non-competitive inhibition of hAChE by two selected promising novel compounds. Two newly prepared compounds were also chosen for docking studies that confirmed apparent π-π or π-cationic interactions aside the cholinesterases catalytic sites. The SAR findings were discussed. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

Kinetics and molecular docking studies of cholinesterase inhibitors derived from water layer of Lycopodiella cernua (L.) Pic. Serm. (II).

PubMed

Hung, Tran Manh; Lee, Joo Sang; Chuong, Nguyen Ngoc; Kim, Jeong Ah; Oh, Sang Ho; Woo, Mi Hee; Choi, Jae Sue; Min, Byung Sun

2015-10-05

Acetylcholinesterase (AChE) inhibitors increase the availability of acetylcholine in central cholinergic synapses and are the most promising drugs currently available for the treatment of Alzheimer's disease (AD). Our screening study indicated that the water fraction of the methanolic extract of Lycopodiella cernua (L.) Pic. Serm. significantly inhibited AChE in vitro. Bioassay-guided fractionation led to the isolation of a new lignan glycoside, lycocernuaside A (12), and fourteen known compounds (1-11 and 13-15). Compound 7 exhibited the most potent AChE inhibitory activity with an IC50 value of 0.23 μM. Compound 15 had the most potent inhibitory activity against BChE and BACE1 with IC50 values of 0.62 and 2.16 μM, respectively. Compounds 4 and 7 showed mixed- and competitive-type AChE inhibition. Compound 7 noncompetitively inhibited BChE whereas 15 showed competitive and 8, 13, and 14 showed mixed-type inhibition. The docking results for complexes with AChE or BChE revealed that inhibitors 4, 7, and 15 stably positioned themselves in several pocket/catalytic domains of the AChE and BChE residues. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Design, synthesis and structure-activity relationships of dual inhibitors of acetylcholinesterase and serotonin transporter as potential agents for Alzheimer's disease.

PubMed

Toda, Narihiro; Tago, Keiko; Marumoto, Shinji; Takami, Kazuko; Ori, Mayuko; Yamada, Naho; Koyama, Kazuo; Naruto, Shunji; Abe, Kazumi; Yamazaki, Reina; Hara, Takao; Aoyagi, Atsushi; Abe, Yasuyuki; Kaneko, Tsugio; Kogen, Hiroshi

2003-05-01

We have designed and synthesized a dual inhibitor of acetylcholinesterase (AChE) and serotonin transporter (SERT) as a novel class of treatment drugs for Alzheimer's disease on the basis of a hypothetical model of the AChE active site. Dual inhibitions of AChE and SERT would bring about greater therapeutic effects than AChE inhibition alone and avoid adverse peripheral effects caused by excessive AChE inhibition. Compound (S)-6j exhibited potent inhibitory activities against AChE (IC(50)=101 nM) and SERT (IC(50)=42 nM). Furthermore, (S)-6j showed inhibitory activities of both AChE and SERT in mice brain following oral administration.

The preparation, in vitro screening and molecular docking of symmetrical bisquaternary cholinesterase inhibitors containing a but-(2E)-en-1,4-diyl connecting linkage.

PubMed

Musilek, Kamil; Pavlikova, Ruzena; Marek, Jan; Komloova, Marketa; Holas, Ondrej; Hrabinova, Martina; Pohanka, Miroslav; Dohnal, Vlastimil; Dolezal, Martin; Gunn-Moore, Frank; Kuca, Kamil

2011-04-01

Carbamate inhibitors (e.g. pyridostigmine bromide) are used as a pre-treatment for the prevention of organophosphorus poisoning. They work by blocking the native function of acetylcholinesterases (AChE) and thus protect AChE against irreversible inhibition by organophosphorus compounds. However, carbamate inhibitors are known for their many undesirable side effects related to the carbamylation of AChE. In this paper, we describe 17 novel bisquaternary compounds and have analysed their effect on AChE inhibition. The newly prepared compounds were evaluated in vitro using both human erythrocyte AChE and human plasmatic butyrylcholinesterase. Their inhibitory ability was expressed as the half maximal inhibitory concentration (IC₅₀) and then compared to the standard carbamate drugs and two AChE reactivators. One of these novel compounds showed promising AChE inhibition in vitro (nM range) and was better than the currently used standards. Additionally, a kinetic assay confirmed the non-competitive inhibition of hAChE by this novel compound. Consequently, the docking results confirmed the apparent π-π or π-cationic interactions with the key amino acid residues of hAChE and the binding of the chosen compound at the enzyme catalytic site.

Development of multifunctional, heterodimeric isoindoline-1,3-dione derivatives as cholinesterase and β-amyloid aggregation inhibitors with neuroprotective properties.

PubMed

Guzior, Natalia; Bajda, Marek; Skrok, Mirosław; Kurpiewska, Katarzyna; Lewiński, Krzysztof; Brus, Boris; Pišlar, Anja; Kos, Janko; Gobec, Stanislav; Malawska, Barbara

2015-03-06

The presented study describes the synthesis, pharmacological evaluation (AChE and BuChE inhibition, beta amyloid anti-aggregation effect and neuroprotective effect), molecular modeling and crystallographic studies of a novel series of isoindoline-1,3-dione derivatives. The target compounds were designed as dual binding site acetylcholinesterase inhibitors with an arylalkylamine moiety binding at the catalytic site of the enzyme and connected via an alkyl chain to a heterocyclic fragment, capable of binding at the peripheral anionic site of AChE. Among these molecules, compound 15b was found to be the most potent and selective AChE inhibitor (IC50EeAChE = 0.034 μM). Moreover, compound 13b in addition to AChE inhibition (IC50 EeAChE = 0.219 μM) possesses additional properties, such as the ability to inhibit Aβ aggregation (65.96% at 10 μM) and a neuroprotective effect against Aβ toxicity at 1 and 3 μM. Compound 13b emerges as a promising multi-target ligand for the further development of the therapy for age-related neurodegenerative disorders. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Chlorpyrifos and malathion have opposite effects on behaviors and brain size that are not correlated to changes in AChE activity.

PubMed

Richendrfer, Holly; Creton, Robbert

2015-07-01

Organophosphates, a type of neurotoxicant pesticide, are used globally for the treatment of pests on croplands and are therefore found in a large number of conventional foods. These pesticides are harmful and potentially deadly if ingested or inhaled in large quantities by causing a significant reduction in acetylcholinesterase (AChE) activity in the central and peripheral nervous system. However, much less is known about the effects of exposure to small quantities of the pesticides on neural systems and behavior during development. In the current study we used zebrafish larvae in order to determine the effects of two of the most widely used organophosphates, chlorpyrifos and malathion, on zebrafish behavior and AChE activity. Embryos and larvae were exposed to the organophosphates during different time points in development and then tested at 5 days post-fertilization for behavioral, neurodevelopmental and AChE abnormalities. The results of the study indicate that chlorpyrifos and malathion cause opposing behaviors in the larvae such as swim speed (hypoactivity vs. hyperactivity) and rest. Additionally, the pesticides affect only certain behaviors, such as thigmotaxis, during specific time points in development that are unrelated to changes in AChE activity. Larvae treated with malathion but not chlorpyrifos also had significantly smaller forebrain and hindbrain regions compared to controls by 5 days post-fertilization. We conclude that exposure to very low concentrations of organophosphate pesticides during development cause abnormalities in behavior and brain size. Copyright © 2015 Elsevier Inc. All rights reserved.

Chlorpyrifos and Malathion have opposite effects on behaviors and brain size that are not correlated to changes in AChE activity

PubMed Central

Richendrfer, Holly; Creton, Robbert

2015-01-01

Organophosphates, a type of neurotoxicant pesticide, are used globally for the treatment of pests on croplands and are therefore found in a large number of conventional foods. These pesticides are harmful and potentially deadly if ingested or inhaled in large quantities by causing a significant reduction in acetylcholinesterase (AChE) activity in the central and peripheral nervous system. However, much less is known about the effects of exposure to small quantities of the pesticides on neural systems and behavior during development. In the current study we used zebrafish larvae in order to determine the effects of two of the most widely used organophosphates, chlorpyrifos and malathion, on zebrafish behavior and AChE activity. Embryos and larvae were exposed to the organophosphates during different time points in development and then tested at 5 days post-fertilization for behavioral, neurodevelopmental and AChE abnormalities. The results of the study indicate that chlorpyrifos and malathion cause opposing behaviors in the larvae such as swim speed (hypoactivity vs. hyperactivity) and rest. Additionally, the pesticides affect only certain behaviors, such as thigmotaxis, during specific time points in development that are unrelated to changes in AChE activity. Larvae treated with malathion but not chlorpyrifos also had significantly smaller forebrain and hindbrain regions compared to controls by 5 days post-fertilization. We conclude that exposure to very low concentrations of organophosphate pesticides during development cause abnormalities in behavior and brain size. PMID:25983063

Acetylcholinesterases from Elapidae snake venoms: biochemical, immunological and enzymatic characterization.

PubMed

Frobert, Y; Créminon, C; Cousin, X; Rémy, M H; Chatel, J M; Bon, S; Bon, C; Grassi, J

1997-05-23

We analyzed 45 batches of venom from 20 different species belonging to 11 genera from the 3 main families of venomous snakes (Elapidae, Viperidae and Crotalidae). We found high acetylcholinesterase (AChE) activity in all venoms from Elapidae, except in those from the Dendroaspis genus. AChE was particularly abundant in Bungarus venoms which contain up to 8 mg of enzyme per gram of dried venom. We could not detect acetylcholinesterase activity in any batch of venom from Viperidae or Crotalidae. Titration of active sites with an organophosphorous agent (MPT) revealed that the AChE of all venoms have similar turnovers (6000 to 8000 s(-1)) which are clearly higher than those of Torpedo and mammalian enzymes but lower than that of Electrophorus. AChEs from the venom of elapid snakes of the Bungarus, Naja, Ophiophagus and Haemacatus genera were purified by affinity chromatography. SDS-PAGE analysis and sucrose gradient centrifugation demonstrated that AChE is exclusively present as a nonamphiphilic monomer. These enzymes are true AChEs, hydrolyzing acetylthiocholine faster than propionylthiocholine and butyrylthiocholine and exhibiting excess substrate inhibition. Twenty-seven different monoclonal antibodies directed against AChE from Bungarus fasciatus venom were raised in mice. Half of them recognized exclusively the Bungarus enzyme while the others cross-reacted with AChEs from other venoms. Polyspecific mAbs were used to demonstrate that venoms from Dendroaspis, which contain the AChE inhibitor fasciculin but lack AChE activity, were also devoid of immunoreactive AChE protein. AChE inhibitors acting at the active site (edrophonium, tacrine) and at the peripheral site (propidium, fasciculin), as well as bis-quaternary ligands (BW284C51, decamethonium), were tested against the venom AChEs from 11 different species. All enzymes had a very similar pattern of reactivity with regard to the different inhibitors, with the exception of fasciculin. AChEs from Naja and

Cerebral Acetylcholine and Choline Contents and Turnover Following Low-Dose Acetylcholinesterase Inhibitor Treatment in Rats

DTIC Science & Technology

2006-05-01

JH, Jr., Romano JA, King JM (1990) Age-related differences in soman toxicity and in blood and brain regional cholinesterase activity . Brain Res.Bull...of OP AChE inhibitors when given in anticipation of exposure to toxic nerve agents. The mechanism of this protection seems to be the pre- occupation of...has indicated effects on blood AChE activity during and shortly after treatment and delayed effects, 2 to 16 weeks post-treatment, on exploratory

Butyrylcholinesterase inhibitors ameliorate cognitive dysfunction induced by amyloid-β peptide in mice

PubMed Central

Furukawa-Hibi, Yoko; Alkam, Tursun; Nitta, Atsumi; Matsuyama, Akihiro; Mizoguchi, Hiroyuki; Suzuki, Kazuhiko; Moussaoui, Saliha; Yu, Qian-Sheng; Greig, Nigel H.; Nagai, Taku; Yamada, Kiyofumi

2016-01-01

The cholinesterase inhibitor, rivastigmine, ameliorates cognitive dysfunction and is approved for the treatment of Alzheimer's disease (AD). Rivastigmine is a dual inhibitor of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE); however, the impact of BuChE inhibition on cognitive dysfunction remains to be determined. We compared the effects of a selective BuChE inhibitor, N1-phenethylnorcymserine (PEC), rivastigmine and donepezil (an AChE-selective inhibitor) on cognitive dysfunction induced by amyloid-β peptide (Aβ1–40) in mice. Five-week-old imprinting control region (ICR) mice were injected intracerebroventricularly (i.c.v.) with either Aβ1–40 or the control peptide Aβ40–1 on Day 0, and their recognition memory was analyzed by a novel object recognition test. Treatment with donepezil (1.0 mg/kg), rivastigmine (0.03, 0.1, 0.3 mg/kg) or PEC (1.0, 3.0 mg/kg) 20 min prior to, or immediately after the acquisition session (Day 4) ameliorated the Aβ1–40 induced memory impairment, indicating a beneficial effect on memory acquisition and consolidation. In contrast, none of the investigated drugs proved effective when administrated before the retention session (Day 5). Repeated daily administration of donepezil, rivastigmine or PEC, on Days 0–3 inclusively, ameliorated the cognitive dysfunction in Aβ1–40 challenged mice. Consistent with the reversal of memory impairments, donepezil, rivastigmine or PEC treatment significantly reduced Aβ1–40 induced tyrosine nitration of hippocampal proteins, a marker of oxidative damage. These results indicate that BuChE inhibition, as well as AChE inhibition, is a viable therapeutic strategy for cognitive dysfunction in AD. PMID:21820013

Pyridostigmine but not 3,4-diaminopyridine exacerbates ACh receptor loss and myasthenia induced in mice by muscle-specific kinase autoantibody

PubMed Central

Morsch, Marco; Reddel, Stephen W; Ghazanfari, Nazanin; Toyka, Klaus V; Phillips, William D

2013-01-01

In myasthenia gravis, the neuromuscular junction is impaired by the antibody-mediated loss of postsynaptic acetylcholine receptors (AChRs). Muscle weakness can be improved upon treatment with pyridostigmine, a cholinesterase inhibitor, or with 3,4-diaminopyridine, which increases the release of ACh quanta. The clinical efficacy of pyridostigmine is in doubt for certain forms of myasthenia. Here we formally examined the effects of these compounds in the antibody-induced mouse model of anti-muscle-specific kinase (MuSK) myasthenia gravis. Mice received 14 daily injections of IgG from patients with anti-MuSK myasthenia gravis. This caused reductions in postsynaptic AChR densities and in endplate potential amplitudes. Systemic delivery of pyridostigmine at therapeutically relevant levels from days 7 to 14 exacerbated the anti-MuSK-induced structural alterations and functional impairment at motor endplates in the diaphragm muscle. No such effect of pyridostigmine was found in mice receiving control human IgG. Mice receiving smaller amounts of MuSK autoantibodies did not display overt weakness, but 9 days of pyridostigmine treatment precipitated generalised muscle weakness. In contrast, one week of treatment with 3,4-diaminopyridine enhanced neuromuscular transmission in the diaphragm muscle. Both pyridostigmine and 3,4-diaminopyridine increase ACh in the synaptic cleft yet only pyridostigmine potentiated the anti-MuSK-induced decline in endplate ACh receptor density. These results thus suggest that ongoing pyridostigmine treatment potentiates anti-MuSK-induced AChR loss by prolonging the activity of ACh in the synaptic cleft. PMID:23440963

Endogenous purines modulate K+ -evoked ACh secretion at the mouse neuromuscular junction.

PubMed

Guarracino, Juan F; Cinalli, Alejandro R; Veggetti, Mariela I; Losavio, Adriana S

2018-06-01

At the mouse neuromuscular junction, adenosine triphosphate (ATP) is co-released with the neurotransmitter acetylcholine (ACh), and once in the synaptic cleft, it is hydrolyzed to adenosine. Both ATP/adenosine diphosphate (ADP) and adenosine modulate ACh secretion by activating presynaptic P2Y 13 and A 1 , A 2A , and A 3 receptors, respectively. To elucidate the action of endogenous purines on K + -dependent ACh release, we studied the effect of purinergic receptor antagonists on miniature end-plate potential (MEPP) frequency in phrenic diaphragm preparations. At 10 mM K + , the P2Y 13 antagonist N-[2-(methylthio)ethyl]-2-[3,3,3-trifluoropropyl]thio-5'-adenylic acid, monoanhydride with (dichloromethylene)bis[phosphonic acid], tetrasodium salt (AR-C69931MX) increased asynchronous ACh secretion while the A 1 , A 3 , and A 2A antagonists 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), (3-Ethyl-5-benzyl-2-methyl-4-phenylethynyl-6-phenyl-1, 4-(±)-dihydropyridine-3,5-, dicarboxylate (MRS-1191), and 2-(2-Furanyl)-7-(2-phenylethyl)-7H-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidin-5-amine (SCH-58261) did not modify neurosecretion. The inhibition of equilibrative adenosine transporters by S-(p-nitrobenzyl)-6-thioinosine provoked a reduction of 10 mM K + -evoked ACh release, suggesting that the adenosine generated from ATP is being removed from the synaptic space by the transporters. At 15 and 20 mM K + , endogenous ATP/ADP and adenosine bind to inhibitory P2Y 13 and A 1 and A 3 receptors since AR-C69931MX, DPCPX, and MRS-1191 increased MEPP frequency. Similar results were obtained when the generation of adenosine was prevented by using the ecto-5'-nucleotidase inhibitor α,β-methyleneadenosine 5'-diphosphate sodium salt. SCH-58261 only reduced neurosecretion at 20 mM K + , suggesting that more adenosine is needed to activate excitatory A 2A receptors. At high K + concentration, the equilibrative transporters appear to be saturated allowing the accumulation of

Novel Cholinesterase Inhibitors Based on O-Aromatic N,N-Disubstituted Carbamates and Thiocarbamates.

PubMed

Krátký, Martin; Štěpánková, Šárka; Vorčáková, Katarína; Švarcová, Markéta; Vinšová, Jarmila

2016-02-11

Based on the presence of carbamoyl moiety, twenty salicylanilide N,N-disubstituted (thio)carbamates were investigated using Ellman's method for their ability to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). O-Aromatic (thio)carbamates exhibited weak to moderate inhibition of both cholinesterases with IC50 values within the range of 1.60 to 311.0 µM. IC50 values for BChE were mostly lower than those obtained for AChE; four derivatives showed distinct selectivity for BChE. All of the (thio)carbamates produced a stronger inhibition of AChE than rivastigmine, and five of them inhibited BChE more effectively than both established drugs rivastigmine and galantamine. In general, 5-chloro-2-hydroxy-N-[4-(trifluoromethyl)-phenyl]benzamide, 2-hydroxy-N-phenylbenzamide as well as N-methyl-N-phenyl carbamate derivatives led to the more potent inhibition. O-{4-Chloro-2-[(4-chlorophenyl)carbamoyl]phenyl} dimethylcarbamothioate was identified as the most effective AChE inhibitor (IC50 = 38.98 µM), while 2-(phenylcarbamoyl)phenyl diphenylcarbamate produced the lowest IC50 value for BChE (1.60 µM). Results from molecular docking studies suggest that carbamate compounds, especially N,N-diphenyl substituted representatives with considerable portion of aromatic moieties may work as non-covalent inhibitors displaying many interactions at peripheral anionic sites of both enzymes. Mild cytotoxicity for HepG2 cells and consequent satisfactory calculated selectivity indexes qualify several derivatives for further optimization.

Old and new acetylcholinesterase inhibitors for Alzheimer's disease.

PubMed

Galimberti, Daniela; Scarpini, Elio

2016-10-01

To date, pharmacological treatment of Alzheimer's disease (AD) includes Acetylcholinesterase Inhibitors (AChEIs) for mild-to-moderate AD, and memantine for moderate-to-severe AD. AChEIs reversibly inhibit acetylcholinesterase (AChE), thus increasing the availability of acetylcholine in cholinergic synapses, enhancing cholinergic transmission. These drugs provide symptomatic short-term benefits, without clearly counteracting the progression of the disease. On the wake of successful clinical trials which lead to the marketing of AChEIs donepezil, rivastigmine and galantamine, many compounds with AChEI properties have been developed and tested mainly in Phase I-II clinical trials in the last twenty years. Here, we review clinical trials initiated and interrupted, and those ongoing so far. Despite many clinical trials with novel AChEIs have been carried out after the registration of those currently used to treat mild to moderate AD, none so far has been successful in a Phase III trial and marketed. Alzheimer's disease is a complex multifactorial disorder, therefore therapy should likely address not only the cholinergic system but also additional neurotransmitters. Moreover, such treatments should be started in very mild phases of the disease, and preventive strategies addressed in elderly people.

Tacrine-based dual binding site acetylcholinesterase inhibitors as potential disease-modifying anti-Alzheimer drug candidates.

PubMed

Camps, Pelayo; Formosa, Xavier; Galdeano, Carles; Gómez, Tània; Muñoz-Torrero, Diego; Ramírez, Lorena; Viayna, Elisabet; Gómez, Elena; Isambert, Nicolás; Lavilla, Rodolfo; Badia, Albert; Clos, M Victòria; Bartolini, Manuela; Mancini, Francesca; Andrisano, Vincenza; Bidon-Chanal, Axel; Huertas, Oscar; Dafni, Thomai; Luque, F Javier

2010-09-06

Two novel families of dual binding site acetylcholinesterase (AChE) inhibitors have been developed, consisting of a tacrine or 6-chlorotacrine unit as the active site interacting moiety, either the 5,6-dimethoxy-2-[(4-piperidinyl)methyl]-1-indanone fragment of donepezil (or the indane derivative thereof) or a 5-phenylpyrano[3,2-c]quinoline system, reminiscent to the tryciclic core of propidium, as the peripheral site interacting unit, and a linker of suitable length as to allow the simultaneous binding at both sites. These hybrid compounds are all potent and selective inhibitors of human AChE, and more interestingly, are able to interfere in vitro both formation and aggregation of the beta-amyloid peptide, the latter effects endowing these compounds with the potential to modify Alzheimer's disease progression. Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.

Pharmacological characterization of RS-1259, an orally active dual inhibitor of acetylcholinesterase and serotonin transporter, in rodents: possible treatment of Alzheimer's disease.

PubMed

Abe, Yasuyuki; Aoyagi, Atsushi; Hara, Takao; Abe, Kazumi; Yamazaki, Reina; Kumagae, Yoshihiro; Naruto, Shunji; Koyama, Kazuo; Marumoto, Shinji; Tago, Keiko; Toda, Narihiro; Takami, Kazuko; Yamada, Naho; Ori, Mayuko; Kogen, Hiroshi; Kaneko, Tsugio

2003-09-01

A dual inhibitor of acetylcholinesterase (AChE) and serotonin transporter (SERT), RS-1259 (4-[1S)-methylamino-3-(4-nitrophenoxy)]propylphenyl N,N-dimethylcarbamate (fumaric acid)(1/2)salt), was newly synthesized. RS-1259 simultaneously inhibited AChE and SERT in the brain following an oral administration in mice and rats. Actual simultaneous elevation of extracellular levels of 5-HT and ACh in the rat hippocampus was confirmed by microdialysis. The compound was as effective as SERT inhibitors such as fluoxetine and fluvoxamine in a 5-hydroxytryptophan-enhancing test in mice. Spatial memory deficits in the two-platform task of a water maze in aged rats were ameliorated by RS-1259 as well as donepezil. Both RS-1259 and donepezil increased the awake episodes in the daytime electroencephalogram of rats. Although RS-1259 was weaker than donepezil in enhancing central cholinergic transmission, as observed by ACh elevation in the hippocampus and memory enhancement in aged rats, the efficacy of RS-1259 on the consciousness level, which reflects the whole activity in the brain, was almost the same as that of donepezil. These results suggest that both cholinergic and serotonergic systems are involved in maintaining brain arousal and that a dual inhibitor of AChE and SERT may be useful for the treatment of cognitive disorders associated with reduced brain activity such as in Alzheimer's disease.

Doxycycline and its quaternary ammonium derivative for adjuvant therapies of chondrosarcoma.

PubMed

Miladi, Imen; Vivier, Magali; Dauplat, Marie-Mélanie; Chatard, Morgane; Besse, Sophie; Vidal, Aurélien; Chassain, Karine; Jean, Betty; Forestier, Christiane; Chezal, Jean-Michel; Rédini, Francoise; Degoul, Francoise; Miot-Noirault, Elisabeth

2017-09-01

This study was conducted during the development of innovative treatment targeting the microenvironment of chondrosarcoma. In this context, MMP inhibitors were conjugated with a quaternary ammonium (QA) function as a targeting ligand to proteoglycans of chondrosarcoma extracellular matrix. Here we report the proof of concept of this strategy applied to the MMP13 inhibitor, doxycycline (Dox). A quaternary ammonium derivative of the MMP13 inhibitor doxycycline (QA-Dox) was synthesized, and its anticancer activity was evaluated in the Swarm rat chondrosarcoma (SRC) model compared with the parent drug doxycycline, in vitro and in vivo. In vivo, dox and QA-Dox efficiency was assessed at equimolar doses according to a q4dx4 schedule by monitoring tumour volume by MRI and PG-targeted scintigraphy. Molecular mechanism (MMP13 expression, proteoglycan level) and histology studies were performed on tumours. The link of QA targeting function to Dox maintained the MMP13 inhibitory activity in vitro. Interestingly, the bacteriostatic activity was lost. SRC cells incubated with both drugs were blocked in S and G2 M phases. Tumour growth inhibition (confirmed by histology) was observed for both Dox and QA-Dox. Undesirable blood effects (leukocyte decrease) were reduced when Dox was targeted to tumour tissue using the QA function. In the SRC model, the MMP13 inhibitor Dox and its QA derivative are promising as adjuvant therapies for chondrosarcoma management.

Acetylcholinesterase (AChE) and heat shock proteins (Hsp70) of gypsy moth (Lymantria dispar L.) larvae in response to long-term fluoranthene exposure.

PubMed

Mrdaković, Marija; Ilijin, Larisa; Vlahović, Milena; Matić, Dragana; Gavrilović, Anja; Mrkonja, Aleksandra; Perić-Mataruga, Vesna

2016-09-01

Polycyclic aromatic hydrocarbons (PAHs) may affect biochemical and physiological processes in living organisms, thus impairing fitness related traits and influencing their populations. This imposes the need for providing early-warning signals of pollution. Our study aimed to examine changes in the activity of acetylcholinesterase (AChE) and the concentration of heat shock proteins (Hsp70) in homogenates of brain tissues of fifth instar gypsy moth (Lymantria dispar L.) larvae, exposed to the ubiquitous PAH, fluoranthene, supplemented to the rearing diet. Significantly increased activity of AChE in larvae fed on the diets with high fluoranthene concentrations suggests the necessity for elucidation of the role of AChE in these insects when exposed to PAH pollution. Significant induction of Hsp70 in gypsy moth larvae reared on the diets containing low fluoranthene concentrations, indicate that changes in the level of Hsp70 might be useful as an indicator of pollution in this widespread forest species. Copyright © 2016 Elsevier Ltd. All rights reserved.

Different Cholinesterase Inhibitor Effects on CSF Cholinesterases in Alzheimer Patients

PubMed Central

Nordberg, Agneta; Darreh-Shori, Taher; Peskind, Elaine; Soininen, Hilkka; Mousavi, Malahat; Eagle, Gina; Lane, Roger

2014-01-01

Background The current study aimed to compare the effects of different cholinesterase inhibitors on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities and protein levels, in the cerebrospinal fluid (CSF) of Alzheimer disease (AD) patients. Methods and Findings AD patients aged 50–85 years were randomized to open-label treatment with oral rivastigmine, donepezil or galantamine for 13 weeks. AChE and BuChE activities were assayed by Ellman’s colorimetric method. Protein levels were assessed by enzyme-linked immunosorbent assay (ELISA). Primary analyses were based on the Completer population (randomized patients who completed Week 13 assessments). 63 patients were randomized to treatment. Rivastigmine was associated with decreased AChE activity by 42.6% and decreased AChE protein levels by 9.3%, and decreased BuChE activity by 45.6% and decreased BuChE protein levels by 21.8%. Galantamine decreased AChE activity by 2.1% and BuChE activity by 0.5%, but increased AChE protein levels by 51.2% and BuChE protein levels by10.5%. Donepezil increased AChE and BuChE activities by 11.8% and 2.8%, respectively. Donepezil caused a 215.2%increase in AChE and 0.4% increase in BuChE protein levels. Changes in mean AChE-Readthrough/Synaptic ratios, which might reflect underlying neurodegenerative processes, were 1.4, 0.6, and 0.4 for rivastigmine, donepezil and galantamine, respectively. Conclusion The findings suggest pharmacologically-induced differences between rivastigmine, donepezil and galantamine. Rivastigmine provides sustained inhibition of AChE and BuChE, while donepezil and galantamine do not inhibit BuChE and are associated with increases in CSF AChE protein levels. The clinical implications require evaluation. PMID:19199870

Different cholinesterase inhibitor effects on CSF cholinesterases in Alzheimer patients.

PubMed

Nordberg, Agneta; Darreh-Shori, Taher; Peskind, Elaine; Soininen, Hilkka; Mousavi, Malahat; Eagle, Gina; Lane, Roger

2009-02-01

The current study aimed to compare the effects of different cholinesterase inhibitors on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities and protein levels, in the cerebrospinal fluid (CSF) of Alzheimer disease (AD) patients. AD patients aged 50-85 years were randomized to open-label treatment with oral rivastigmine, donepezil or galantamine for 13 weeks. AChE and BuChE activities were assayed by Ellman's colorimetric method. Protein levels were assessed by enzyme-linked immunosorbent assay (ELISA). Primary analyses were based on the Completer population (randomized patients who completed Week 13 assessments). 63 patients were randomized to treatment. Rivastigmine was associated with decreased AChE activity by 42.6% and decreased AChE protein levels by 9.3%, and decreased BuChE activity by 45.6% and decreased BuChE protein levels by 21.8%. Galantamine decreased AChE activity by 2.1% and BuChE activity by 0.5%, but increased AChE protein levels by 51.2% and BuChE protein levels by 10.5%. Donepezil increased AChE and BuChE activities by 11.8% and 2.8%, respectively. Donepezil caused a 215.2% increase in AChE and 0.4% increase in BuChE protein levels. Changes in mean AChE-Readthrough/Synaptic ratios, which might reflect underlying neurodegenerative processes, were 1.4, 0.6, and 0.4 for rivastigmine, donepezil and galantamine, respectively. The findings suggest pharmacologically-induced differences between rivastigmine, donepezil and galantamine. Rivastigmine provides sustained inhibition of AChE and BuChE, while donepezil and galantamine do not inhibit BuChE and are associated with increases in CSF AChE protein levels. The clinical implications require evaluation.

3D MI-DRAGON: new model for the reconstruction of US FDA drug- target network and theoretical-experimental studies of inhibitors of rasagiline derivatives for AChE.

PubMed

Prado-Prado, Francisco; García-Mera, Xerardo; Escobar, Manuel; Alonso, Nerea; Caamaño, Olga; Yañez, Matilde; González-Díaz, Humberto

2012-01-01

The number of neurodegenerative diseases has been increasing in recent years. Many of the drug candidates to be used in the treatment of neurodegenerative diseases present specific 3D structural features. An important protein in this sense is the acetylcholinesterase (AChE), which is the target of many Alzheimer's dementia drugs. Consequently, the prediction of Drug-Protein Interactions (DPIs/nDPIs) between new drug candidates and specific 3D structure and targets is of major importance. To this end, we can use Quantitative Structure-Activity Relationships (QSAR) models to carry out a rational DPIs prediction. Unfortunately, many previous QSAR models developed to predict DPIs take into consideration only 2D structural information and codify the activity against only one target. To solve this problem we can develop some 3D multi-target QSAR (3D mt-QSAR) models. In this study, using the 3D MI-DRAGON technique, we have introduced a new predictor for DPIs based on two different well-known software. We have used the MARCH-INSIDE (MI) and DRAGON software to calculate 3D structural parameters for drugs and targets respectively. Both classes of 3D parameters were used as input to train Artificial Neuronal Network (ANN) algorithms using as benchmark dataset the complex network (CN) made up of all DPIs between US FDA approved drugs and their targets. The entire dataset was downloaded from the DrugBank database. The best 3D mt-QSAR predictor found was an ANN of Multi-Layer Perceptron-type (MLP) with profile MLP 37:37-24-1:1. This MLP classifies correctly 274 out of 321 DPIs (Sensitivity = 85.35%) and 1041 out of 1190 nDPIs (Specificity = 87.48%), corresponding to training Accuracy = 87.03%. We have validated the model with external predicting series with Sensitivity = 84.16% (542/644 DPIs; Specificity = 87.51% (2039/2330 nDPIs) and Accuracy = 86.78%. The new CNs of DPIs reconstructed from US FDA can be used to explore large DPI databases in order to discover both new drugs

Effects of cholinesterase inhibitors on the activities and protein levels of cholinesterases in the cerebrospinal fluid of patients with Alzheimer's disease: a review of recent clinical studies.

PubMed

Darreh-Shori, T; Soininen, H

2010-02-01

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by cognitive decline associated with a deficit in cholinergic function. Inhibitors of acetylcholinesterase (AChE) and/or butyrylcholinesterase (BuChE), such as donepezil, galantamine or rivastigmine, are widely prescribed as symptomatic treatments for AD. These agents exhibit a wide variation in their pharmacological properties. Here we review clinical data from 1998 to 2009 investigating the effect of different cholinesterase inhibitor treatments on the levels and activities of cholinesterases in the cerebrospinal fluid (CSF) of AD patients. These studies suggest that treatment with rapidly-reversible cholinesterase inhibitors (e.g. donepezil, galantamine, tacrine) are associated with marked and significant upregulation of AChE activities and protein levels in the CSF of AD patients. In contrast, pseudo-irreversible cholinesterase inhibition (e.g. rivastigmine) is associated with a significant decrease in both CSF AChE and BuChE activities, with no upregulation of CSF protein levels. Additionally, donepezil is associated with a decrease in the level of the AChE-R isoform relative to the synaptic AChE-S isoform, whereas rivastigmine seems to increase this ratio. These findings suggest that these agents exert different effects on CSF cholinesterases. The clinical effects of these pharmacological differences are yet to be fully established.

[The action of quaternary ammonium derivatives on respiration and nitrate reduction in Pseudomonas aeruginosa].

PubMed

Bievskiĭ, A N

1994-01-01

It was revealed that the same dosages of quaternary ammonium derivatives, such as decamethoxin and cetyltrimethylammonium bromide, inhibited the respiratory chains and caused destruction of Pseudomonas aeruginosa under aerobic conditions more effectively than under anaerobic ones when anions of nitric acid were the terminal acceptors of electrons. It was also registered that Pseudomonas were able to dissimilatory nitrate reduction in the media under the polysaccharide layer that was produced by these bacteria: this fact possibly proves the possibility of survival of denitrifying bacteria in solutions with high concentrations of quaternary ammonium salts. The data obtained permit supposing that inhibitors of respiratory chains and oxidizers may be used as potentiators of the antimicrobial action of quaternary ammonium derivatives.

Synthesis of some new 3-coumaranone and coumarin derivatives as dual inhibitors of acetyl- and butyrylcholinesterase.

PubMed

Alipour, Masoumeh; Khoobi, Mehdi; Nadri, Hamid; Sakhteman, Amirhossein; Moradi, Alireza; Ghandi, Mehdi; Foroumadi, Alireza; Shafiee, Abbas

2013-08-01

A novel series of coumarin and 3-coumaranone derivatives encompassing the phenacyl pyridinium moiety were synthesized and evaluated for their acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activity using Ellman's method. All compounds presented inhibitory activity against both AChE and BuChE in the micromolar range. The molecular docking simulations revealed that all compounds were dual binding site inhibitors of AChE. A kinetic study was performed and the mechanism of enzyme inhibition was proved to be of mixed type. All compounds were tested for their antioxidant activity and no significant activity was observed. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Combination of human acetylcholinesterase and serum albumin sensing surfaces as highly informative analytical tool for inhibitor screening.

PubMed

Fabini, Edoardo; Tramarin, Anna; Bartolini, Manuela

2018-06-05

In the continuous research for potential drug lead candidates, the availability of highly informative screening methodologies may constitute a decisive element in the selection of best-in-class compounds. In the present study, a surface plasmon resonance (SPR)-based assay was developed and employed to investigate interactions between human recombinant AChE (hAChE) and four known ligands: galantamine, tacrine, donepezil and edrophonium. To this aim, a sensor chip was functionalized with hAChE using mild immobilization conditions to best preserve enzyme integrity. Binding affinities and, for the first time, kinetic rate constants for all drug-hAChE complexes formation/disruption were determined. Inhibitors were classified in two groups: slow-reversible and fast-reversible binders according to respective target residence time. Combining data obtained on drug-target residence time with data obtained on serum albumin binding levels, a good correlation with potency, plasma protein binding in vivo, and administration regimen was found. The outcomes of this work demonstrated that the developed SPR-based assay is suitable for the screening, the binding affinity ranking and the kinetic evaluation of hAChE inhibitors. The method proposed ensures a simpler and cost-effective assay to quantify kinetic rate constants for inhibitor-hAChE interaction as compared with other proposed and published methods. Eventually, the determination of residence time in combination with preliminary ADME studies might constitute a better tool to predict in vivo behaviour, a key information for the research of new potential drug candidates. Copyright © 2018 Elsevier B.V. All rights reserved.

Multipotent cholinesterase/monoamine oxidase inhibitors for the treatment of Alzheimer's disease: design, synthesis, biochemical evaluation, ADMET, molecular modeling, and QSAR analysis of novel donepezil-pyridyl hybrids.

PubMed

Bautista-Aguilera, Oscar M; Esteban, Gerard; Chioua, Mourad; Nikolic, Katarina; Agbaba, Danica; Moraleda, Ignacio; Iriepa, Isabel; Soriano, Elena; Samadi, Abdelouahid; Unzeta, Mercedes; Marco-Contelles, José

2014-01-01

The design, synthesis, and biochemical evaluation of donepezil-pyridyl hybrids (DPHs) as multipotent cholinesterase (ChE) and monoamine oxidase (MAO) inhibitors for the potential treatment of Alzheimer's disease (AD) is reported. The 3D-quantitative structure-activity relationship study was used to define 3D-pharmacophores for inhibition of MAO A/B, acetylcholinesterase (AChE), and butyrylcholinesterase (BuChE) enzymes and to design DPHs as novel multi-target drug candidates with potential impact in the therapy of AD. DPH14 (Electrophorus electricus AChE [EeAChE]: half maximal inhibitory concentration [IC50] =1.1±0.3 nM; equine butyrylcholinesterase [eqBuChE]: IC50 =600±80 nM) was 318-fold more potent for the inhibition of AChE, and 1.3-fold less potent for the inhibition of BuChE than the reference compound ASS234. DPH14 is a potent human recombinant BuChE (hBuChE) inhibitor, in the same range as DPH12 or DPH16, but 13.1-fold less potent than DPH15 for the inhibition of human recombinant AChE (hAChE). Compared with donepezil, DPH14 is almost equipotent for the inhibition of hAChE, and 8.8-fold more potent for hBuChE. Concerning human monoamine oxidase (hMAO) A inhibition, only DPH9 and 5 proved active, compound DPH9 being the most potent (IC50 [MAO A] =5,700±2,100 nM). For hMAO B, only DPHs 13 and 14 were moderate inhibitors, and compound DPH14 was the most potent (IC50 [MAO B] =3,950±940 nM). Molecular modeling of inhibitor DPH14 within EeAChE showed a binding mode with an extended conformation, interacting simultaneously with both catalytic and peripheral sites of EeAChE thanks to a linker of appropriate length. Absortion, distribution, metabolism, excretion and toxicity analysis showed that structures lacking phenyl-substituent show better druglikeness profiles; in particular, DPHs13-15 showed the most suitable absortion, distribution, metabolism, excretion and toxicity properties. Novel donepezil-pyridyl hybrid DPH14 is a potent, moderately selective hACh

Inhibition of spicule elongation in sea urchin embryos by the acetylcholinesterase inhibitor eserine.

PubMed

Ohta, Kazumasa; Takahashi, Chifumi; Tosuji, Hiroaki

2009-08-01

The activity of acetylcholinesterase (AchE) increases rapidly after the gastrula stage of sea urchin development. In this report, changes in activity and in the molecular differentiation of AchE were investigated. AchE activity increased slightly during gastrulation and rose sharply thereafter, and was dependent on new RNA synthesis. No activity of butyrylcholinesterase was found. Morphogenesis in sea urchin embryos was inhibited by the AchE inhibitor eserine, which specifically inhibited arm rod formation but not body rod formation. Spicule formation and enzyme activity in cultured micromeres were inhibited by eserine in a dose-dependent manner. During gastrulation, two molecular forms of AchE were detected with polyacrylamide gel electrophoresis. The appearance of an additional band on the gel was consistent with the occurrence of a remarkable increase in the enzyme activity. This additional band appeared as a larger molecular form in Anthocidaris crassispina, Hemicentrotus pulcherrimus, Stomopneustes variolaris, and Strongylocentrotus nudus, and as a smaller form in Clypeaster japonicus and Temnopleurus hardwicki. These results suggest that the change in the molecular form of AchE induced a change in enzymatic activity that in turn may play a role in spicule elongation in sea urchin embryos.

Dihydroagarofuranoid Sesquiterpenes as Acetylcholinesterase Inhibitors from Celastraceae Plants: Maytenus disticha and Euonymus japonicus.

PubMed

Alarcón, Julio; Cespedes, Carlos L; Muñoz, Evelyn; Balbontin, Cristian; Valdes, Francisco; Gutierrez, Margarita; Astudillo, Luis; Seigler, David S

2015-12-02

Natural cholinesterase inhibitors have been found in many biological sources. Nine compounds with agarofuran (epoxyeudesmane) skeletons were isolated from seeds and aerial parts of Maytenus disticha and Euonymus japonicus. The identification and structural elucidation of compounds were based on spectroscopic data analyses. All compounds had inhibitory acetylcholinesterase (AChE) activity. These natural compounds, which possessed mixed or uncompetitive mechanisms of inhibitory activity against AChE, may be considered as models for the design and development of new naturally occurring drugs for management strategies for neurodegenerative diseases. This is the first report of these chemical structures for seeds of M. disticha.

Exploration of the susceptibility of AChE from the poultry red mite Dermanyssus gallinae (Acari: Mesostigmata) to organophosphates in field isolates from France.

PubMed

Roy, Lise; Chauve, Claude; Delaporte, Jean; Inizan, Gilbert; Buronfosse, Thierry

2009-06-01

The red fowl mite Dermanyssus gallinae (De Geer, 1778) is a hematophagous mite species, which is very commonly found in layer facilities in Europe. The economic and animal health impact of this parasite is quite important. In laying hen houses, organophosphates are almost the only legally usable chemicals. Detecting a target resistance can be useful in order to limit the emergence of resistant populations. The acetylcholinesterase (AChE) activity and the enzyme sensitivity to paraoxon was investigated in 39 field samples and compared to a susceptible reference strain (SSK). Insensitivity factor values (expressed as IC50 ratio) obtained from field isolates compared to SSK revealed some polymorphism but not exceeding a 6-fold difference. The kinetic characteristics of AChE from some field samples showed some difference in KM values for acetylthiocholine and inhibition kinetics performed with diethyl paraoxon exhibited a 5.5-fold difference in the bimolecular rate constant in one field isolate. Taken together, these data suggested that differences in AChE susceptibility to organophosphates may exist in D. gallinae but no resistant population was found.

Design and prediction of new acetylcholinesterase inhibitor via quantitative structure activity relationship of huprines derivatives.

PubMed

Zhang, Shuqun; Hou, Bo; Yang, Huaiyu; Zuo, Zhili

2016-05-01

Acetylcholinesterase (AChE) is an important enzyme in the pathogenesis of Alzheimer's disease (AD). Comparative quantitative structure-activity relationship (QSAR) analyses on some huprines inhibitors against AChE were carried out using comparative molecular field analysis (CoMFA), comparative molecular similarity indices analysis (CoMSIA), and hologram QSAR (HQSAR) methods. Three highly predictive QSAR models were constructed successfully based on the training set. The CoMFA, CoMSIA, and HQSAR models have values of r (2) = 0.988, q (2) = 0.757, ONC = 6; r (2) = 0.966, q (2) = 0.645, ONC = 5; and r (2) = 0.957, q (2) = 0.736, ONC = 6. The predictabilities were validated using an external test sets, and the predictive r (2) values obtained by the three models were 0.984, 0.973, and 0.783, respectively. The analysis was performed by combining the CoMFA and CoMSIA field distributions with the active sites of the AChE to further understand the vital interactions between huprines and the protease. On the basis of the QSAR study, 14 new potent molecules have been designed and six of them are predicted to be more active than the best active compound 24 described in the literature. The final QSAR models could be helpful in design and development of novel active AChE inhibitors.

6-Methyluracil derivatives as acetylcholinesterase inhibitors for treatment of Alzheimer's disease.

PubMed

Zueva, I V; Semenov, V E; Mukhamedyarov, M A; Lushchekina, S V; Kharlamova, A D; Petukhova, E O; Mikhailov, A S; Podyachev, S N; Saifina, L F; Petrov, K A; Minnekhanova, O A; Zobov, V V; Nikolsky, E E; Masson, P; Reznik, V S

2015-01-01

Alzheimer's disease (AD) is the major age-related progressive neurodegenerative disorder. The brain of AD patients suffers from loss of cholinergic neurons and decreased number of synapses [1]. AD is caused by an imbalance between Aβ production and clearance, resulting in increased amount of Aβ in various forms [2]. Reduction of Aβ production and increasing clearance of Aβ pathogenic forms are key targets in the development of potential therapeutic agents for AD treatment. Unfortunately, only nosotropic approaches for treatment of AD are currently effective in humans. These approaches mainly focus on the inhibition of brain acetyl-cholinesterase (AChE) to increase lifetime of cerebral acetylcholine [3]. It is important to emphasize that AChE itself promotes the formation of Aβ fibrils in vitro and Aβ plaques in the cerebral cortex of transgenic mouse models of AD [4]. This property of AChE results from interaction between Aβ and the peripheral anionic site of the enzyme (PAS) [5]. Dual binding site inhibitors of both catalytic active site (CAS) and PAS can simultaneously improve cognition and slow down the rate of Aβ-induced neural degeneration. Unfortunately, the assortment of AChE PAS ligands is still extremely limited. To study putative advantages of AChE non-charged PAS inhibitors based on 6-methyluracil derivatives for the treatment of Alzheimer's disease. In vitro studies. Concentration of drug producing 50% of AChE/BuChE activity inhibition (IC50) was measured using the method of Ellman et al. [6]. Toxicological experiments were performed using IP injection of the different compounds in mice. LD50, dose (in mg/kg) causing lethal effects in 50% of animals was taken as a criterion of toxicity [7]. The ability of compound to block in vitro AChE-induced Aβ1-40 aggregation was studied using a thioflavin T (ThT) fluorescent probe [8].In vivo biological assays. For in vivo blood-brain barrier permeation assay brains were removed 30 min after IP injection

Cigarette toxin 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) induces experimental pancreatitis through α7 nicotinic acetylcholine receptors (nAChRs) in mice

PubMed Central

Alahmari, A. A.; Sreekumar, B.; Patel, V.; Ashat, M.; Alexandre, M.; Uduman, A. K.; Akinbiyi, E. O.; Ceplenski, A.; Shugrue, C. A.; Kolodecik, T. R.; Messenger, S. W.; Groblewski, G. E.; Gorelick, F. S.

2018-01-01

Clinical studies have shown that cigarette smoking is a dose-dependent and independent risk factor for acute pancreatitis. Cigarette smoke contains nicotine which can be converted to the potent receptor ligand and toxin, NNK [4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone]. Previously, we have shown that NNK induces premature activation of pancreatic zymogens in rats, an initiating event in pancreatitis, and this activation is prevented by pharmacologic inhibition of nicotinic acetylcholine receptors (nAChR). In this study, we determined whether NNK mediates pancreatitis through the α7 isoform of nAChR using α7nAChR knockout mice. PCR analysis confirmed expression of non-neuronal α7nAChR in C57BL/6 (WT) mouse and human acinar cells. NNK treatment stimulated trypsinogen activation in acini from WT but not α7nAChR-/- mice. NNK also stimulated trypsinogen activation in human acini. To further confirm these findings, WT and α7nAChR-/- mice were treated with NNK in vivo and markers of pancreatitis were measured. As observed in acini NNK treatment induced trypsinogen activation in WT but not α7nAChR-/- mice. NNK also induced other markers of pancreatitis including pancreatic edema, vacuolization and pyknotic nuclei in WT but not α7nAChR-/- animals. NNK treatment led to increased neutrophil infiltration, a marker of inflammation, in WT mice and to a significantly lesser extent in α7nAChR-/- mice. We also examined downstream targets of α7nAChR activation and found that calcium and PKC activation are involved down stream of NNK stimulation of α7nAChR. In this study we used genetic deletion of the α7nAChR to confirm our previous inhibitor studies that demonstrated NNK stimulates pancreatitis by activating this receptor. Lastly, we demonstrate that NNK can also stimulate zymogen activation in human acinar cells and thus may play a role in human disease. PMID:29870540

Parkinson's disease (PD) with dementia and falls is improved by AChEI? A preliminary study report.

PubMed

Lauretani, Fulvio; Galuppo, Laura; Costantino, Cosimo; Ticinesi, Andrea; Ceda, Gianpaolo; Ruffini, Livio; Nardelli, Anna; Maggio, Marcello

2016-06-01

Advanced PD is often associated with cognitive impairment and frequent falls. We describe a suggestive case report of PD associated with mild cognitive impairment (MCI) and falls. The aim of our study was to test alteration in balance potentially related to use of acetylcholinesterase inhibitor (AchEI). We address this hypothesis after keeping the patient in stable dosage of dopamine agonist. We describe an initial pharmacological management in a 78-year-old man affected by Parkinson disease (PD) associated with mild cognitive impairment (MCI) and history of falls. The diagnosis of PD was also confirmed by SPECT with DATSCAN, after CT-brain exclusion of potential other causes of the symptoms. Cognitive and motor performances of the patient were initially evaluated by Mini Mental Examination State Examination (MMSE), Short Physical Performance Battery (SPPB) and Romberg test. We also recorded gait parameters using an accelerometer, while balance and stability were assessed by stabilometric platform with open and closed eyes. We repeated cognitive and motor tests and gait and balance evaluation after stable dosage of dopamine agonist before and after introduction of AchEI. After starting dopamine agonist therapy, there was a significant improvement in gait parameters (speed, stride/min, stride length, swing duration, and decrease in gait cycle duration and rolling duration). When stable dosage of dopamine agonist was reached, AchEI was introduced obtaining not only a significant improvement of cognitive performance, but also a significant positive change in balance. We hypothesize that AchEI could improve stability, balance and postural instability in addition to cognitive performance in PD with MCI and balance deficits.

Nicotinic ACh Receptors as Therapeutic Targets in CNS Disorders

PubMed Central

Dineley, Kelly T.; Pandya, Anshul A.; Yakel, Jerrel L.

2015-01-01

The neurotransmitter acetylcholine (ACh) can regulate neuronal excitability by acting on the cys-loop cation-conducting ligand-gated nicotinic ACh receptor channels (nAChRs). These receptors are widely distributed throughout the central nervous system, being expressed on neurons and non-neuronal cells, where they participate in a variety of physiological responses such as anxiety, the central processing of pain, food intake, nicotine seeking behavior, and cognitive functions. In the mammalian brain, nine different subunits have been found thus far, which assemble into pentameric complexes with much subunit diversity; however the α7 and α4β2 subtypes predominate in the CNS. Neuronal nAChR dysfunction is involved in the pathophysiology of many neurological disorders. Here we will briefly discuss the functional makeup and expression of the nAChRs in the mammalian brain, and their role as targets in neurodegenerative diseases (in particular Alzheimer’s disease), neurodevelopmental disorders (in particular autism and schizophrenia), and neuropathic pain. PMID:25639674

Nicotinic ACh receptors as therapeutic targets in CNS disorders.

PubMed

Dineley, Kelly T; Pandya, Anshul A; Yakel, Jerrel L

2015-02-01

The neurotransmitter acetylcholine (ACh) can regulate neuronal excitability by acting on the cys-loop cation-conducting ligand-gated nicotinic ACh receptor (nAChR) channels. These receptors are widely distributed throughout the central nervous system (CNS), being expressed on neurons and non-neuronal cells, where they participate in a variety of physiological responses such as anxiety, the central processing of pain, food intake, nicotine seeking behavior, and cognitive functions. In the mammalian brain, nine different subunits have been found thus far, which assemble into pentameric complexes with much subunit diversity; however, the α7 and α4β2 subtypes predominate in the CNS. Neuronal nAChR dysfunction is involved in the pathophysiology of many neurological disorders. Here we will briefly discuss the functional makeup and expression of the nAChRs in mammalian brain, and their role as targets in neurodegenerative diseases (in particular Alzheimer's disease, AD), neurodevelopmental disorders (in particular autism and schizophrenia), and neuropathic pain. Published by Elsevier Ltd.

Rapid Screening and Characterization of Acetylcholinesterase Inhibitors from Yinhuang Oral Liquid Using Ultrafiltration-liquid Chromatography-electrospray Ionization Tandem Mass Spectrometry

PubMed Central

Zhang, Haomin; Guo, Yinan; Meng, Lingwen; Sun, Hui; Yang, Yinping; Gao, Ying; Sun, Jiaming

2018-01-01

Background: At present, approximately 17–25 million people in the world suffer from Alzheimer's disease (AD). The most efficacious and acceptable therapeutic drug clinically are the acetylcholinesterase inhibitors (AChEIs). Yinhuang oral liquid is a Chinese medicine preparation which contains AChEIs according to the literatures. However, no strategy has been presented for rapid screening and identification of AChEIs from Yinhuang oral liquid. Objective: To develop a method for rapid screening and identification of AChEIs from Yinhuang oral liquid using ultrafiltration–liquid chromatography–electrospray ionization tandem mass spectrometry (UF-LC-ESI-MS/MS). Materials and Methods: In this study, UF incubation conditions such as enzyme concentration, incubation time, and incubation temperature were optimized so as to get better screening results. The AChEIs from Yinhuang oral liquid were identified by high-performance liquid chromatography-ESI-MS and the improved Ellman method was used for the AChE inhibitory activity test in vitro. Results: The results showed that Yinhuang oral liquid can inhibit the activity of AChE. We screened and identified seven compounds with potential AChE inhibitory activity from Yinhuang oral liquid, which provided experimental basis for the treatment and prevention of AD. Conclusion: The current technique was used to directly screen the active ingredients with acetylcholinesterase inhibition from complex traditional Chinese medicine, which was simple, rapid, accurate, and suitable for high-throughput screening of AChEI from complex systems. SUMMARY A UF-LC-ESI-MS/MS method for rapid screening and identification of AChEIs from Yinhuang oral liquid was developedSeven compounds were screened and identified with potential AChE inhibitory activity from Yinhuang oral liquidIt provided experimental basis of Yinhuang oral liquid for the treating and preventing AD. Abbreviations used: (AD): Alzheimer's disease; (UF

Synthesis, pharmacology and molecular docking on multifunctional tacrine-ferulic acid hybrids as cholinesterase inhibitors against Alzheimer's disease.

PubMed

Zhu, Jie; Yang, Hongyu; Chen, Yao; Lin, Hongzhi; Li, Qi; Mo, Jun; Bian, Yaoyao; Pei, Yuqiong; Sun, Haopeng

2018-12-01

The cholinergic hypothesis has long been a "polar star" in drug discovery for Alzheimer's disease (AD), resulting in many small molecules and biological drug candidates. Most of the drugs marketed for AD are cholinergic. Herein, we report our efforts in the discovery of cholinesterases inhibitors (ChEIs) as multi-target-directed ligands. A series of tacrine-ferulic acid hybrids have been designed and synthesised. All these compounds showed potent acetyl-(AChE) and butyryl cholinesterase(BuChE) inhibition. Among them, the optimal compound 10g, was the most potent inhibitor against AChE (electrophorus electricus (eeAChE) half maximal inhibitory concentration (IC 50 ) = 37.02 nM), it was also a strong inhibitor against BuChE (equine serum (eqBuChE) IC 50  = 101.40 nM). Besides, it inhibited amyloid β-protein self-aggregation by 65.49% at 25 μM. In subsequent in vivo scopolamine-induced AD models, compound 10g obviously ameliorated the cognition impairment and showed preliminary safety in hepatotoxicity evaluation. These data suggest compound 10g as a promising multifunctional agent in the drug discovery process against AD.

Revealing the importance of linkers in K-series oxime reactivators for tabun-inhibited AChE using quantum chemical, docking and SMD studies.

PubMed

Ghosh, Shibaji; Chandar, Nellore Bhanu; Jana, Kalyanashis; Ganguly, Bishwajit

2017-08-01

Inhibition of acetylcholinesterase (AChE) with organophosphorus compounds has a detrimental effect on human life. Oxime K203 seems to be one of the promising reactivators for tabun-inhibited AChE than (K027, K127, and K628). These reactivators differ only in the linker units between the two pyridinium rings. The conformational analyses performed with quantum chemical RHF/6-31G* level for K027, K127, K203 and K628 showed that the minimum energy conformers have different orientations of the active and peripheral pyridinium rings for these reactivator molecules. K203 with (-CH 2 -CH=CH-CH 2 -) linker unit possesses more open conformation compared to the other reactivators. Such orientation of K203 experiences favorable interaction with the surrounding residues of catalytic anionic site (CAS) and peripheral anionic site (PAS) of tabun-inhibited AChE. From the steered molecular dynamics simulations, it has been observed that the oxygen atom of the oxime group of K203 reactivator approaches nearest to the P-atom of the SUN203 (3.75 Å) at lower time scales (less than ~1000 ps) as compared to the other reactivators. K203 experiences less number of hydrophobic interaction with the PAS residues which is suggested to be an important factor for the efficient reactivation process. In addition, K203 crates large number of H-bonding with CAS residues SUN203, Phe295, Tyr337, Phe338 and His447. K203 barely changes its conformation during the SMD simulation process and hence the energy penalty to adopt any other conformation is minimal in this case as compared to the other reactivators. The molecular mechanics and Poisson-Boltzmann surface area binding energies obtained for the interaction of K203 inside the gorge of tabun inhibited AChE is substantially higher (-290.2 kcal/mol) than the corresponding K628 reactivator (-260.4 kcal/mol), which also possess unsaturated aromatic linker unit.

Revealing the importance of linkers in K-series oxime reactivators for tabun-inhibited AChE using quantum chemical, docking and SMD studies

NASA Astrophysics Data System (ADS)

Ghosh, Shibaji; Chandar, Nellore Bhanu; Jana, Kalyanashis; Ganguly, Bishwajit

2017-08-01

Inhibition of acetylcholinesterase (AChE) with organophosphorus compounds has a detrimental effect on human life. Oxime K203 seems to be one of the promising reactivators for tabun-inhibited AChE than (K027, K127, and K628). These reactivators differ only in the linker units between the two pyridinium rings. The conformational analyses performed with quantum chemical RHF/6-31G* level for K027, K127, K203 and K628 showed that the minimum energy conformers have different orientations of the active and peripheral pyridinium rings for these reactivator molecules. K203 with (-CH2-CH=CH-CH2-) linker unit possesses more open conformation compared to the other reactivators. Such orientation of K203 experiences favorable interaction with the surrounding residues of catalytic anionic site (CAS) and peripheral anionic site (PAS) of tabun-inhibited AChE. From the steered molecular dynamics simulations, it has been observed that the oxygen atom of the oxime group of K203 reactivator approaches nearest to the P-atom of the SUN203 (3.75 Å) at lower time scales (less than 1000 ps) as compared to the other reactivators. K203 experiences less number of hydrophobic interaction with the PAS residues which is suggested to be an important factor for the efficient reactivation process. In addition, K203 crates large number of H-bonding with CAS residues SUN203, Phe295, Tyr337, Phe338 and His447. K203 barely changes its conformation during the SMD simulation process and hence the energy penalty to adopt any other conformation is minimal in this case as compared to the other reactivators. The molecular mechanics and Poisson-Boltzmann surface area binding energies obtained for the interaction of K203 inside the gorge of tabun inhibited AChE is substantially higher (-290.2 kcal/mol) than the corresponding K628 reactivator (-260.4 kcal/mol), which also possess unsaturated aromatic linker unit.

Quaternary and Geomorphology.

ERIC Educational Resources Information Center

Andrews, J. T.; Graf, W. L.

1983-01-01

Highlights conferences and meetings of organizations involved with quaternary geology and geomorphology, including International Union of Quaternary Research Conference held in Moscow. The impetus of a revision of "The Quaternary of the United States" resulted from this conference. Includes activities/aims of "Friends of the…

Novel donepezil-based inhibitors of acetyl- and butyrylcholinesterase and acetylcholinesterase-induced beta-amyloid aggregation.

PubMed

Camps, Pelayo; Formosa, Xavier; Galdeano, Carles; Gómez, Tània; Muñoz-Torrero, Diego; Scarpellini, Michele; Viayna, Elisabet; Badia, Albert; Clos, M Victòria; Camins, Antoni; Pallàs, Mercè; Bartolini, Manuela; Mancini, Francesca; Andrisano, Vincenza; Estelrich, Joan; Lizondo, Mònica; Bidon-Chanal, Axel; Luque, F Javier

2008-06-26

A novel series of donepezil-tacrine hybrids designed to simultaneously interact with the active, peripheral and midgorge binding sites of acetylcholinesterase (AChE) have been synthesized and tested for their ability to inhibit AChE, butyrylcholinesterase (BChE), and AChE-induced A beta aggregation. These compounds consist of a unit of tacrine or 6-chlorotacrine, which occupies the same position as tacrine at the AChE active site, and the 5,6-dimethoxy-2-[(4-piperidinyl)methyl]-1-indanone moiety of donepezil (or the indane derivative thereof), whose position along the enzyme gorge and the peripheral site can be modulated by a suitable tether that connects tacrine and donepezil fragments. All of the new compounds are highly potent inhibitors of bovine and human AChE and BChE, exhibiting IC50 values in the subnanomolar or low nanomolar range in most cases. Moreover, six out of the eight hybrids of the series, particularly those bearing an indane moiety, exhibit a significant A beta antiaggregating activity, which makes them promising anti-Alzheimer drug candidates.

Exploration of a Library of 3,4-(Methylenedioxy)aniline-Derived Semicarbazones as Dual Inhibitors of Monoamine Oxidase and Acetylcholinesterase: Design, Synthesis, and Evaluation.

PubMed

Tripathi, Rati K P; Rai, Gopal K; Ayyannan, Senthil R

2016-06-06

A library of 3,4-(methylenedioxy)aniline-derived semicarbazones was designed, synthesized, and evaluated as monoamine oxidase (MAO) and acetylcholinesterase (AChE) inhibitors for the treatment of neurodegenerative diseases. Most of the new compounds selectively inhibited MAO-B and AChE, with IC50 values in the micro- or nanomolar ranges. Compound 16, 1-(2,6-dichlorobenzylidene)-4-(benzo[1,3]dioxol-5-yl)semicarbazide presented a balanced multifunctional profile of MAO-A (IC50 =4.52±0.032 μm), MAO-B (IC50 =0.059±0.002 μm), and AChE (IC50 =0.0087±0.0002 μm) inhibition without neurotoxicity. Kinetic studies revealed that compound 16 exhibits competitive and reversible inhibition against MAO-A and MAO-B, and mixed-type inhibition against AChE. Molecular docking studies further revealed insight into the possible interactions within the enzyme-inhibitor complexes. The most active compounds were found to interact with the enzymes through hydrogen bonding and hydrophobic interactions. Additionally, in silico molecular properties and ADME properties of the synthesized compounds were calculated to explore their drug-like characteristics. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis and biological evaluation of novel tacrine derivatives and tacrine-coumarin hybrids as cholinesterase inhibitors.

PubMed

Hamulakova, Slavka; Janovec, Ladislav; Hrabinova, Martina; Spilovska, Katarina; Korabecny, Jan; Kristian, Pavol; Kuca, Kamil; Imrich, Jan

2014-08-28

A series of novel tacrine derivatives and tacrine-coumarin heterodimers were designed, synthesized, and biologically evaluated for their potential inhibitory effect on both acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Of these compounds, tacrine-coumarin heterodimer 7c and tacrine derivative 6b were found to be the most potent inhibitors of human AChE (hAChE), demonstrating IC50 values of 0.0154 and 0.0263 μM. Ligands 6b, 6c, and 7c exhibited the highest levels of inhibitory activity against human BuChE (hBuChE), demonstrating IC50 values that range from 0.228 to 0.328 μM. Docking studies were performed in order to predict the binding modes of compounds 6b and 7c with hAChE/hBuChE.

Treatment of Visual Hallucinations in Schizophrenia by Acetylcholinesterase Inhibitors: a case report

PubMed Central

Abad, Nazir Hashemi; Doulatabad, Najafi Shala; Mohammadi, Ali

2011-01-01

Schizophrenia and various neurological disorders have some signs and symptoms. Visual hallucinations are one of such disorders. The related studies in some diseases for example Parkinson Disease and Lewy Body Dementia indicate that Acetylcholine (Ach) plays a significant role in neuropsychiatric manifestation and its association with visual hallucination; therefore, visual hallucinations occur due to the depletion of Ach. Drug therapies such as Cholinesterase inhibitors (ChEIs) for increasing Ach level may be beneficial in treating visual hallucination. AchEI's have been used in the treatment of visual hallucinations in Dementia and Parkinson's Disease. We thought that a similar Ach depletion may cause visual hallucinations in patients with schizophrenia and may provide a target for drug treatment. We had a patient with schizophrenia whose psychotic symptoms responded to the treatment plan, but her visual hallucination did not. However, the patient's visual hallucination successfully responded to Rivastigmine (AchEI). This case illustrates the use of an AchEI in the treatment of refractory visual hallucinations in a patient with schizophrenia. PMID:22952543

AChR-specific immunosuppressive therapy of myasthenia gravis.

PubMed

Luo, Jie; Lindstrom, Jon

2015-10-15

Myasthenia gravis (MG) is an organ-specific autoimmune disease characterized by muscle fatigability. In most cases, it is mediated by autoantibodies targeting muscle nicotinic acetylcholine receptors (AChRs) at the neuromuscular junction. Experimental autoimmune myasthenia gravis (EAMG) is an animal model for MG, which is usually induced by immunization with AChR purified from fish electric organ. Pathological autoantibodies to AChRs are directed at the extracellular surface, especially the main immunogenic region (MIR). Current treatments for MG can help many but not all patients. Antigen-specific immunosuppressive therapy for MG that specifically suppresses the autoimmune response without affecting the entire immune system and avoids side effects of general immunosuppression is currently unavailable. Early attempts at antigen-specific immunosuppression for EAMG using AChR extracellular domain sequences that form epitopes for pathological autoantibodies risked provoking autoimmunity rather than suppressing it. We discovered a novel approach to specific immunosuppression of EAMG with a therapeutic vaccine consisting of bacterially-expressed human AChR cytoplasmic domains, which has the potential to specifically suppress MG without danger of causing exacerbation. This approach prevents development of chronic EAMG when initiated immediately after the acute phase of EAMG, and rapidly reverses established chronic EAMG when started during the chronic phase of EAMG. Successfully treated rats exhibited long-term resistance to re-induction of EAMG. In this review we also discuss the current understanding of the mechanisms by which the therapy works. Vaccination with AChR cytoplasmic domains in adjuvant is promising as a safe, antigen-specific, potent, effective, rapidly acting, and long lasting approach to therapy of MG. Copyright © 2015 Elsevier Inc. All rights reserved.

Alkaloids as a source of potential anticholinesterase inhibitors for the treatment of Alzheimer's disease.

PubMed

Konrath, Eduardo Luis; Passos, Carolina dos Santos; Klein, Luiz Carlos; Henriques, Amélia T

2013-12-01

The inhibition of acetylcholinesterase (AChE), the key enzyme in the breakdown of acetylcholine, is currently the main pharmacological strategy available for Alzheimer's disease (AD). In this sense, many alkaloids isolated from natural sources, such as physostigmine, have been long recognized as acetyl- and butyrylcholinesterase (BChE) inhibitors. Since the approval of galantamine for the treatment of AD patients, the search for new anticholinesterase alkaloids has escalated, leading to promising candidates such as huperzine A. This review aims to summarize recent advances in current knowledge on alkaloids as AChE and BChE inhibitors, highlighting structure-activity relationship (SAR) and docking studies. Natural alkaloids belonging to the steroidal/triterpenoidal, quinolizidine, isoquinoline and indole classes, mainly distributed within Buxaceae, Amaryllidaceae and Lycopodiaceae, are considered important sources of alkaloids with anti-enzymatic properties. Investigations into the possible SARs for some active compounds are based on molecular modelling studies, predicting the mode of interaction of the molecules with amino acid residues in the active site of the enzymes. Following this view, an increasing interest in achieving more potent and effective analogues makes alkaloids good chemical templates for the development of new cholinesterase inhibitors. The anticholinesterase activity of alkaloids, together with their structural diversity and physicochemical properties, makes them good candidate agents for the treatment of AD. © 2013 Royal Pharmaceutical Society.

Microwave-assisted synthesis of novel purine nucleosides as selective cholinesterase inhibitors.

PubMed

Schwarz, S; Csuk, R; Rauter, A P

2014-04-21

Alzheimer's disease (AD), the most common form of senile dementia, is characterized by high butyrylcholinesterase (BChE) levels in the brain in later AD stages, for which no treatment is available. Pursuing our studies on selective BChE inhibitors, that may contribute to understand the role of this enzyme in disease progression, we present now microwave-assisted synthesis and anticholinesterase activity of a new nucleoside series embodying 6-chloropurine or 2-acetamido-6-chloropurine linked to D-glucosyl, D-galactosyl and D-mannosyl residues. It was designed to assess the contribution of sugar stereochemistry, purine structure and linkage to the sugar for cholinesterase inhibition efficiency and selectivity. Compounds were subjected to Ellman's assay and their inhibition constants determined. The α-anomers were the most active compounds, while selectivity for BChE or acetylcholinesterase (AChE) inhibition could be tuned by the purine base, by the glycosyl moiety and by N(7)-ligation. Some of the nucleosides were far more potent than the drug galantamine, and the most promising competitive and selective BChE inhibitor, the N(7)-linked 2-acetamido-α-D-mannosylpurine, showed a Ki of 50 nM and a selectivity factor of 340 fold for BChE over AChE.

Synthesis, characterization, and molecular docking analysis of novel benzimidazole derivatives as cholinesterase inhibitors.

PubMed

Yoon, Yeong Keng; Ali, Mohamed Ashraf; Wei, Ang Chee; Choon, Tan Soo; Khaw, Kooi-Yeong; Murugaiyah, Vikneswaran; Osman, Hasnah; Masand, Vijay H

2013-08-01

Two series of novel acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitors containing benzimidazole core structure were synthesized by a four-step reaction pathway starting from 4-fluoro-3-nitrobenzoic acid as the basic compound. The structure of the novel benzimidazoles was characterized and confirmed by the elemental and mass spectral analyses as well as (1)H NMR spectroscopic data. Of the 34 novel synthesized compounds, three benzimidazoles revealed AChE inhibition with IC50<10 μM. The highest inhibitory activity (IC50=5.12 μM for AChE and IC50=8.63 μM for BChE) corresponds to the compound 5IIc (ethyl 1-(3-(1H-imidazol-1-yl)propyl)-2-(4-nitrophenyl)-1H-benzo[d]imidazole-5-carboxylate). The relationship between lipophilicity and the chemical structures as well as their limited structure-activity relationship was discussed. Copyright © 2013 Elsevier Inc. All rights reserved.

Acetylcholinesterase Regulates Skeletal In Ovo Development of Chicken Limbs by ACh-Dependent and -Independent Mechanisms

PubMed Central

Spieker, Janine; Ackermann, Anica; Salfelder, Anika; Vogel-Höpker, Astrid; Layer, Paul G.

2016-01-01

Formation of the vertebrate limb presents an excellent model to analyze a non-neuronal cholinergic system (NNCS). Here, we first analyzed the expression of acetylcholinesterase (AChE) by IHC and of choline acetyltransferase (ChAT) by ISH in developing embryonic chicken limbs (stages HH17-37). AChE outlined formation of bones, being strongest at their distal tips, and later also marked areas of cell death. At onset, AChE and ChAT were elevated in two organizing centers of the limb anlage, the apical ectodermal ridge (AER) and zone of polarizing activity (ZPA), respectively. Thereby ChAT was expressed shortly after AChE, thus strongly supporting a leading role of AChE in limb formation. Then, we conducted loss-of-function studies via unilateral implantation of beads into chicken limb anlagen, which were soaked in cholinergic components. After varying periods, the formation of cartilage matrix and of mineralizing bones was followed by Alcian blue (AB) and Alizarin red (AR) stainings, respectively. Both acetylcholine (ACh)- and ChAT-soaked beads accelerated bone formation in ovo. Notably, inhibition of AChE by BW284c51, or by the monoclonal antibody MAB304 delayed cartilage formation. Since bead inhibition of BChE was mostly ineffective, an ACh-independent action during BW284c51 and MAB304 inhibition was indicated, which possibly could be due to an enzymatic side activity of AChE. In conclusion, skeletogenesis in chick is regulated by an ACh-dependent cholinergic system, but to some extent also by an ACh-independent aspect of the AChE protein. PMID:27574787

Acetylcholinesterase Regulates Skeletal In Ovo Development of Chicken Limbs by ACh-Dependent and -Independent Mechanisms.

PubMed

Spieker, Janine; Ackermann, Anica; Salfelder, Anika; Vogel-Höpker, Astrid; Layer, Paul G

2016-01-01

Formation of the vertebrate limb presents an excellent model to analyze a non-neuronal cholinergic system (NNCS). Here, we first analyzed the expression of acetylcholinesterase (AChE) by IHC and of choline acetyltransferase (ChAT) by ISH in developing embryonic chicken limbs (stages HH17-37). AChE outlined formation of bones, being strongest at their distal tips, and later also marked areas of cell death. At onset, AChE and ChAT were elevated in two organizing centers of the limb anlage, the apical ectodermal ridge (AER) and zone of polarizing activity (ZPA), respectively. Thereby ChAT was expressed shortly after AChE, thus strongly supporting a leading role of AChE in limb formation. Then, we conducted loss-of-function studies via unilateral implantation of beads into chicken limb anlagen, which were soaked in cholinergic components. After varying periods, the formation of cartilage matrix and of mineralizing bones was followed by Alcian blue (AB) and Alizarin red (AR) stainings, respectively. Both acetylcholine (ACh)- and ChAT-soaked beads accelerated bone formation in ovo. Notably, inhibition of AChE by BW284c51, or by the monoclonal antibody MAB304 delayed cartilage formation. Since bead inhibition of BChE was mostly ineffective, an ACh-independent action during BW284c51 and MAB304 inhibition was indicated, which possibly could be due to an enzymatic side activity of AChE. In conclusion, skeletogenesis in chick is regulated by an ACh-dependent cholinergic system, but to some extent also by an ACh-independent aspect of the AChE protein.

A facile stereoselective synthesis of dispiro-indeno pyrrolidine/pyrrolothiazole-thiochroman hybrids and evaluation of their antimycobacterial, anticancer and AchE inhibitory activities.

PubMed

Bharkavi, Chelliah; Vivek Kumar, Sundaravel; Ashraf Ali, Mohamed; Osman, Hasnah; Muthusubramanian, Shanmugam; Perumal, Subbu

2016-11-15

A facile stereoselective synthesis of novel dispiro indeno pyrrolidine/pyrrolothiazole-thiochroman hybrids has been achieved by 1,3-dipolar cycloaddition of azomethine ylides, generated in situ from ninhydrin and sarcosine/thiaproline, on a series of 3-benzylidenethiochroman-4-ones. The synthesised compounds were screened for their antimycobacterial, anticancer and AchE inhibition activities. Compound 4l (IC 50 1.07μM) has been found to exhibit the most potent antimycobacterial activity compared to cycloserine (12 times), pyrimethamine (37 times) and ethambutol (IC 50 <1.56μM) and 6l (IC 50 =2.87μM) is more active than both cycloserine (4 times) and pyrimethamine (12 times). Three compounds, 4a, 6b and 6i, display good anticancer activity against CCRF-CEM cell lines. Compounds 6g and 4g display maximum AchE inhibitory activity with IC 50 values of 1.10 and 1.16μmol/L respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

In vitro functional interactions of acetylcholine esterase inhibitors and muscarinic receptor antagonists in the urinary bladder of the rat.

PubMed

Killi, Uday K; Wsol, Vladimir; Soukup, Ondrej; Kuca, Kamil; Winder, Michael; Tobin, Gunnar

2014-02-01

Obidoxime, a weak acetylcholine-esterase (AChE) inhibitor, exerts muscarinic receptor antagonism with a significant muscarinic M2 receptor selective profile. The current examinations aimed to determine the functional significance of muscarinic M2 receptors in the state of AChE inhibition, elucidating muscarinic M2 and M3 receptor interaction. In the in vitro examinations, methacholine evoked concentration-dependent bladder contractile and atrial frequency inhibitory responses. Although atropine abolished both, methoctramine (1 μmol/L) only affected the cholinergic response in the atrial preparations. However, in the presence of methoctramine, physostigmine, an AChE inhibitor, increased the basal tension of the bladder strip preparations (+68%), as well as the contractile responses to low concentrations of methacholine (< 5 μmol/L; +90-290%). In contrast to physostigmine, obidoxime alone raised the basal tension (+58%) and the responses to low concentrations of methacholine (< 5 μmol/L; +80-450%). Physostigmine concentration-dependently increased methacholine-evoked responses, similarly to obidoxime at low concentrations. However, at large concentrations (> 5 μmol/L), obidoxime, because of its unselective muscarinic receptor antagonism, inhibited the methacholine bladder responses. In conclusion, the current results show that muscarinic M2 receptors inhibit muscarinic M3 receptor-evoked contractile responses to low concentrations of acetylcholine in the synaptic cleft. The muscarinic M2 and M3 receptor crosstalk could be a counteracting mechanism in the treatment of AChE inhibition when using reactivators, such as obidoxime. © 2013 Wiley Publishing Asia Pty Ltd.

Synthesis, biological evaluation and molecular modelling of diversely functionalized heterocyclic derivatives as inhibitors of acetylcholinesterase/butyrylcholinesterase and modulators of Ca2+ channels and nicotinic receptors.

PubMed

Marco, José L; de los Ríos, Cristóbal; García, Antonio G; Villarroya, Mercedes; Carreiras, M Carmo; Martins, Carla; Eleutério, Ana; Morreale, Antonio; Orozco, M; Luque, F Javier

2004-05-01

The synthesis and the biological activity of compounds 5-40 as inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), as well as modulators of voltage-dependent Ca(2+) channels and nicotinic receptors, are described. These molecules are tacrine analogues, which have been prepared from polyfunctionalized 6-amino-5-cyano-4H-pyrans, 6-amino-5-cyano-pyridines and 5-amino-2-aryl-3-cyano-1,3-oxazoles via Friedländer reaction with selected cycloalkanones. These compounds are moderate acetylcholinesterase and butyrylcholinesterase inhibitors, the BuChE/AChE selectivity of the most active molecules ranges from 10.0 (compound 29) to 76.9 (compound 16). Interestingly, the 'oxazolo-tacrine' derivatives are devoid of any activity. All compounds showed an important inhibitory effect on the nicotinic acetylcholine receptor. Most of them also blocked L-type Ca(2+) channels, and three of them, 64, 19 and 67, the non-L type of Ca(2+) channels. Molecular modelling studies suggest that these compounds might bind at the peripheral binding site of AChE, which opens the possibility to design inhibitors able to bind at both, the catalytic and peripheral binding sites of the enzyme.

(-)-Epicatechin derivate from Orostachys japonicus as potential inhibitor of the human butyrylcholinesterase.

PubMed

Kim, Jang Hoon; Lee, Sang-Hyun; Lee, Hyun Woo; Sun, Ya Nan; Jang, Won-Hee; Yang, Seo-Young; Jang, Hae-Dong; Kim, Young Ho

2016-10-01

Cholinesterase inhibitors block the bioconversion of neurotransmitters by cholinesterase in the nervous system. Epicatechin derivatives (1, 3 and 5), polyphenols (6 and 7) from Orostachys japonicus, and catechin derivatives (2 and 4) from our in-house library were evaluated for their inhibitory activity on cholinesterase. Compound 5 exhibited IC50 values of 58.3±2.4 and 17.8±3.8μg/mL on AChE and BuChE, respectively. Compound 5 inhibited BuChE more strongly than AChE through a competitive behavior. In silico binding positions of 5 in the active site were predicted using Autodock 4.2 and processed in a 10000-ps molecular dynamics simulation to assess the stability of compound 5 binding. Copyright © 2016 Elsevier B.V. All rights reserved.

Biological Evaluation of Azomethine-dihydroquinazolinone Conjugates as Cancer and Cholinesterase Inhibitors.

PubMed

Iqbal, Jamshed; Saeed, Aamer; Shah, Syed J A; al-Rashida, Mariya; Shams-ul Mahmood

2016-01-01

In an attempt to discover novel anti-cancer agents and potent cholinesterase inhibitors, 11 azomethine-dihydroquinazolinone conjugates were evaluated against lung carcinoma cells and cholinesterases. Most of the compounds exhibited significant cytotoxicity at low micromolar concentrations and were less toxic to normal cells. After 24 h incubation period, 2i showed maximum cytotoxicity. The 4-bromine substituted compounds showed higher acetylcholinesterase (AChE) inhibitory activity than other screened compounds. The most active compound 2c, among the series, had an IC50 value 209.8 µM against AChE. The tested compounds showed less inhibition against butyrylcholinesterase. Molecular docking studies were performed in order to investigate the plausible binding modes of synthesized compounds. The compounds can be further optimized to treat cancer and Alzheimer's disease. These derivatives may open new pathways for introducing new therapies for curing cancer and senile dementia.

Association of health symptoms with low-level exposure to organophosphates, DNA damage, AChE activity, and occupational knowledge and practice among rice, corn, and double-crop farmers

PubMed Central

Hongsibsong, Surat; Sittitoon, Nalin; Sapbamrer, Ratana

2017-01-01

Objectives: This study aims to determine (1) total dialkylphosphate (ΣDAP) levels, occupational knowledge and practice, DNA damage, AChE activity, and health symptoms in rice, corn, and double-crop farmers; (2) the association of health symptoms with ΣDAP levels, occupational knowledge and practice, DNA damage, and AChE activity in farmers; and (3) the prevalence of health symptoms between farmers and non-farmers. Methods: A cross-sectional study was conducted by interviewing as well as analyzing urine and blood samples during July to August 2014. Results: There were no differences in ΣDAP levels, AChE activity, and occupational knowledge and practice scores among all farmer groups. In terms of health symptoms related to ΣDAP, AChE activity, DNA damage, and occupational knowledge and practice, pesticide-related symptoms were determined, including breathlessness, chest pain, dry throat, numbness, muscle weakness, cramp, headache, dizziness, eye irritation, white/red rash, and white/red pimple, which were classified as respiratory, muscle, nervous, and epithelial symptoms. A remarkable finding was that farmers had a significantly higher prevalence of muscle weakness (odds ratio (OR)=3.79) and numbness (OR=3.45) as compared with non-farmers. Conclusion: Our findings, therefore, suggest that a long-term low-level exposure to organophosphates (OPs) may be associated with an increasing prevalence of muscle symptoms. However, a further cohort study incorporating sensitive health outcomes and measurement of multiple pesticides monitoring on a larger scale is warranted. PMID:28077823

Association of health symptoms with low-level exposure to organophosphates, DNA damage, AChE activity, and occupational knowledge and practice among rice, corn, and double-crop farmers.

PubMed

Hongsibsong, Surat; Sittitoon, Nalin; Sapbamrer, Ratana

2017-03-28

This study aims to determine (1) total dialkylphosphate (ΣDAP) levels, occupational knowledge and practice, DNA damage, AChE activity, and health symptoms in rice, corn, and double-crop farmers; (2) the association of health symptoms with ΣDAP levels, occupational knowledge and practice, DNA damage, and AChE activity in farmers; and (3) the prevalence of health symptoms between farmers and non-farmers. A cross-sectional study was conducted by interviewing as well as analyzing urine and blood samples during July to August 2014. There were no differences in ΣDAP levels, AChE activity, and occupational knowledge and practice scores among all farmer groups. In terms of health symptoms related to ΣDAP, AChE activity, DNA damage, and occupational knowledge and practice, pesticide-related symptoms were determined, including breathlessness, chest pain, dry throat, numbness, muscle weakness, cramp, headache, dizziness, eye irritation, white/red rash, and white/red pimple, which were classified as respiratory, muscle, nervous, and epithelial symptoms. A remarkable finding was that farmers had a significantly higher prevalence of muscle weakness (odds ratio (OR)=3.79) and numbness (OR=3.45) as compared with non-farmers. Our findings, therefore, suggest that a long-term low-level exposure to organophosphates (OPs) may be associated with an increasing prevalence of muscle symptoms. However, a further cohort study incorporating sensitive health outcomes and measurement of multiple pesticides monitoring on a larger scale is warranted.

Inhibitor Profile of bis(n)-tacrines and N-methylcarbamates on Acetylcholinesterase from Rhipicephalus (Boophilus) microplus and Phlebotomus papatasi

USDA-ARS?s Scientific Manuscript database

The cattle tick, Rhipicephalus (Boophilus) microplus (Bm), and the sand fly, Phlebotomus papatasi (Pp), are disease vectors to cattle and humans, respectively. The purpose of this study was to characterize the inhibitor profile of acetylcholinesterases from Bm (BmAChE1) and Pp (PpAchE) compared to h...

Circadian Rhythms of Heart Rate and Locomotion After Treatment With Low-Dose Acetylcholinesterase Inhibitors

DTIC Science & Technology

2006-01-01

with pyridostigmine bromide (PB), a carbamate AChE by air conditioned vans and air-freight to the Laboratory inhibitor that does not cross the blood ...15. SUBJECT TERMS Nerve agents, sarin, pyridostigmine bromide, cerebral glucose utilization, cerebrovascular circulation, low dose cholinesterase ...March 2006" Accepted 12 May 2006 ABSTRACT: This study tested the hypothesis that repeated exposure to low levels of sarin, pyridostigmine bromide (PB

Drug binding to the acetylcholine receptor: Nitroxide analogs of phencyclidine and a local anesthetic

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palma, A.L.

1988-01-01

The interaction of noncompetitive inhibitors (NCIs) with Torpedo californica native nicotinic acetylcholine receptor (nAChR) membranes was examined primarily by the technique of electron paramagnetic resonance (EPR) spectroscopy. The goal of this work being to define some of the physical characteristics for the site(s) of association between an NCI and the nAChR membrane. A nitroxide labeled analog of a quaternary amine local anesthetic, 2-(N,N-dimethyl-N-4-(2,2,6,6-tetramethylpiperidinoxyl)amino)-ethyl 4-hexyloxybenzoate iodide (C6SLMeI), displays a strongly immobilized EPR component when added to nAChR membranes in the presence of carbamylcholine (carb). To further this work, a nitroxide labeled analog of phencyclidine (PCP), a potent NCI, was synthesized. 4-phenyl-4-(1-piperidinyl)-2,2,6,6-tetramethylpiperidinoxylmore » (PPT) exhibited one-third the potency of PCP in inhibiting nAChR mediated ion flux, and from competition binding studies with ({sup 3}H)PCP displayed a K{sub D} of 0.21 {mu}M towards a carb desensitized nAChR and a K{sub 0.5} of 18 {mu}M for a resting {alpha}-bungarotoxin treated nAChR.« less

The inhibition, reactivation and mechanism of VX-, sarin-, fluoro-VX and fluoro-sarin surrogates following their interaction with HuAChE and HuBuChE.

PubMed

Chao, Chih-Kai; Balasubramanian, Narayanaganesh; Gerdes, John M; Thompson, Charles M

2018-06-16

In this study, the mechanisms of HuAChE and HuBChE inhibition by Me-P(O) (OPNP) (OR) [PNP = p-nitrophenyl; R = CH 2 CH 3 , CH 2 CH 2 F, OCH(CH 3 ) 2 , OCH(CH 3 ) (CH 2 F)] representing surrogates and fluoro-surrogates of VX and sarin were studied by in vitro kinetics and mass spectrometry. The in vitro measures showed that the VX- and fluoro-VX surrogates were relatively strong inhibitors of HuAChE and HuBChE (k i  ∼ 10 5 -10 6  M -1 min -1 ) and underwent spontaneous and 2-PAM-mediated reactivation within 30 min. The sarin surrogates were weaker inhibitors of HuAChE and HuBChE (k i  ∼ 10 4 -10 5  M -1 min -1 ), and in general did not undergo spontaneous reactivation, although HuAChE adducts were partially reactivatable at 18 h using 2-PAM. The mechanism of HuAChE and HuBChE inhibition by the surrogates was determined by Q-TOF and MALDI-TOF mass spectral analyses. The surrogate-adducted proteins were trypsin digested and the active site-containing peptide bearing the OP-modified serine identified by Q-TOF as triply- and quadruply-charged ions representing the respective increase in mass of the attached OP moiety. Correspondingly, monoisotopic ions of the tryptic peptides representing the mass increase of the OP-adducted peptide was identified by MALDI-TOF. The mass spectrometry analyses validated the identity of the OP moiety attached to HuAChE or HuBChE as MeP(O) (OR)-O-serine peptides (loss of the PNP leaving group) via mechanisms consistent with those found with chemical warfare agents. MALDI-TOF MS analyses of the VX-modified peptides versus time showed a steady reduction in adduct versus parent peptide (reactivation), whereas the sarin-surrogate-modified peptides remained largely intact over the course of the experiment (24 h). Overall, the presence of a fluorine atom on the surrogate modestly altered the rate constants of inhibition and reactivation, however, the mechanism of inhibition (ejection of PNP group) did not change

Identification of quaternary ammonium compounds as potent inhibitors of hERG potassium channels

PubMed Central

Xia, Menghang; Shahane, Sampada; Huang, Ruili; Titus, Steven A.; Shum, Enoch; Zhao, Yong; Southall, Noel; Zheng, Wei; Witt, Kristine L.; Tice, Raymond R.; Austin, Christopher P.

2011-01-01

The human ether-a-go-go-related gene (hERG) channel, a member of a family of voltage-gated potassium (K+) channels, plays a critical role in the repolarization of the cardiac action potential. The reduction of hERG channel activity as a result of adverse drug effects or genetic mutations may cause QT interval prolongation and potentially lead to acquired long QT syndrome. Thus, screening for hERG channel activity is important in drug development. Cardiotoxicity associated with the inhibition of hERG channels by environmental chemicals is also a public health concern. To assess the inhibitory effects of environmental chemicals on hERG channel function, we screened the National Toxicology Program (NTP) collection of 1408 compounds by measuring thallium influx into cells through hERG channels. Seventeen compounds with hERG channel inhibition were identified with IC50 potencies ranging from 0.26 to 22 μM. Twelve of these compounds were confirmed as hERG channel blockers in an automated whole cell patch clamp experiment. In addition, we investigated the structure-activity relationship of seven compounds belonging to the quaternary ammonium compound (QAC) series on hERG channel inhibition. Among four active QAC compounds, tetra-n-octylammonium bromide was the most potent with an IC50 value of 260 nM in the thallium influx assay and 80 nM in the patch clamp assay. The potency of this class of hERG channel inhibitors appears to depend on the number and length of their aliphatic side-chains surrounding the charged nitrogen. Profiling environmental compound libraries for hERG channel inhibition provides information useful in prioritizing these compounds for cardiotoxicity assessment in vivo. PMID:21362439

Comparative functional expression of nAChR subtypes in rodent DRG neurons.

PubMed

Smith, Nathan J; Hone, Arik J; Memon, Tosifa; Bossi, Simon; Smith, Thomas E; McIntosh, J Michael; Olivera, Baldomero M; Teichert, Russell W

2013-01-01

We investigated the functional expression of nicotinic acetylcholine receptors (nAChRs) in heterogeneous populations of dissociated rat and mouse lumbar dorsal root ganglion (DRG) neurons by calcium imaging. By this experimental approach, it is possible to investigate the functional expression of multiple receptor and ion-channel subtypes across more than 100 neuronal and glial cells simultaneously. Based on nAChR expression, DRG neurons could be divided into four subclasses: (1) neurons that express predominantly α3β4 and α6β4 nAChRs; (2) neurons that express predominantly α7 nAChRs; (3) neurons that express a combination of α3β4/α6β4 and α7 nAChRs; and (4) neurons that do not express nAChRs. In this comparative study, the same four neuronal subclasses were observed in mouse and rat DRG. However, the expression frequency differed between species: substantially more rat DRG neurons were in the first three subclasses than mouse DRG neurons, at all developmental time points tested in our study. Approximately 70-80% of rat DRG neurons expressed functional nAChRs, in contrast to only ~15-30% of mouse DRG neurons. Our study also demonstrated functional coupling between nAChRs, voltage-gated calcium channels, and mitochondrial Ca(2) (+) transport in discrete subsets of DRG neurons. In contrast to the expression of nAChRs in DRG neurons, we demonstrated that a subset of non-neuronal DRG cells expressed muscarinic acetylcholine receptors and not nAChRs. The general approach to comparative cellular neurobiology outlined in this paper has the potential to better integrate molecular and systems neuroscience by uncovering the spectrum of neuronal subclasses present in a given cell population and the functionally integrated signaling components expressed in each subclass.

Carbamate derivatives of indolines as cholinesterase inhibitors and antioxidants for the treatment of Alzheimer's disease.

PubMed

Yanovsky, Inessa; Finkin-Groner, Efrat; Zaikin, Andrey; Lerman, Lena; Shalom, Hila; Zeeli, Shani; Weill, Tehilla; Ginsburg, Isaac; Nudelman, Abraham; Weinstock, Marta

2012-12-13

The cascade of events that occurs in Alzheimer's disease involving oxidative stress and the reduction in cholinergic transmission can be better addressed by multifunctional drugs than cholinesterase inhibitors alone. For this purpose, we prepared a large number of derivatives of indoline-3-propionic acids and esters. They showed scavenging activity against different radicals in solution and significant protection against cytotoxicity in cardiomyocytes and primary cultures of neuronal cells exposed to H2O2 species and serum deprivation at concentrations ranging from 1 nM to 10 μM depending on the compound. For most of the indoline-3-propionic acid derivatives, introduction of N-methyl-N-ethyl or N-methyl-N-(4-methoxyphenyl) carbamate moieties at positions 4, 6, or 7 conferred both acetyl (AChE) and butyryl (BuChE) cholinesterase inhibitory activities at similar concentrations to those that showed antioxidant activity. The most potent AChE inhibitors were 120 (3-(2-aminoethyl) indolin-4-yl ethyl(methyl)carbamate dihydrochloride) and 94 (3-(3-methoxy-3-oxopropyl)-4-(((4-methoxyphenyl)(methyl) carbamoyl)oxy)indolin-1-ium hydrochloride) with IC50s of 0.4 and 1.2 μM, respectively.

Histone deacetylase inhibitors improve learning consolidation in young and in KA-induced-neurodegeneration and SAMP-8-mutant mice.

PubMed

Fontán-Lozano, Angela; Romero-Granados, Rocío; Troncoso, Julieta; Múnera, Alejandro; Delgado-García, José María; Carrión, Angel M

2008-10-01

Histone deacetylases (HDAC) are enzymes that maintain chromatin in a condensate state, related with absence of transcription. We have studied the role of HDAC on learning and memory processes. Both eyeblink classical conditioning (EBCC) and object recognition memory (ORM) induced an increase in histone H3 acetylation (Ac-H3). Systemic treatment with HDAC inhibitors improved cognitive processes in EBCC and in ORM tests. Immunohistochemistry and gene expression analyses indicated that administration of HDAC inhibitors decreased the stimulation threshold for Ac-H3, and gene expression to reach the levels required for learning and memory. Finally, we evaluated the effect of systemic administration of HDAC inhibitors to mice models of neurodegeneration and aging. HDAC inhibitors reversed learning and consolidation deficits in ORM in these models. These results point out HDAC inhibitors as candidate agents for the palliative treatment of learning and memory impairments in aging and in neurodegenerative disorders.

Design, synthesis and preliminary structure-activity relationship investigation of nitrogen-containing chalcone derivatives as acetylcholinesterase and butyrylcholinesterase inhibitors: a further study based on Flavokawain B Mannich base derivatives.

PubMed

Liu, Haoran; Fan, Haoqun; Gao, Xiaohui; Huang, Xueqing; Liu, Xianjun; Liu, Linbo; Zhou, Chao; Tang, Jingjing; Wang, Qiuan; Liu, Wukun

2016-08-01

In order to study the structure-activity relationship of Flavokawain B Mannich-based derivatives as acetylcholinesterase (AChE) inhibitors in our recent investigation, 20 new nitrogen-containing chalcone derivatives (4 a-8d) were designed, synthesized, and evaluated for AChE inhibitory activity in vitro. The results suggested that amino alkyl side chain of chalcone dramatically influenced the inhibitory activity against AChE. Among them, compound 6c revealed the strongest AChE inhibitory activity (IC50 value: 0.85 μmol/L) and the highest selectivity against AChE over BuChE (ratio: 35.79). Enzyme kinetic study showed that the inhibition mechanism of compound 6c against AChE was a mixed-type inhibition. The molecular docking assay showed that this compound can both bind with the catalytic site and the peripheral site of AChE.

Furoquinoline Alkaloids from the Leaves of Evodia lepta as Potential Cholinesterase Inhibitors and their Molecular Docking.

PubMed

Sichaem, Jirapast; Rojpitikul, Thanawan; Sawasdee, Pattara; Lugsannangarm, Kiattisak; Santi, Tip-pyang

2015-08-01

Nine furoquinoline alkaloids (1-9) were isolated from the leaves of Evodia lepta based on bioassay-guided fractionation and chromatographic techniques. All isolates were evaluated for their cholinesterase (ChEs) inhibitory activities, in which kokusaginine (7) and melineurine (5) exhibited the highest activity toward AChE and BChE, respectively. Lineweaver-Burk plots indicated that 5 and 7 were mixed mode inhibitors of both ChE enzymes. Molecular docking studies on the binding sites of AChE and BChE were performed in order to afford a molecular insight into the mode of action of these active compounds. From this study these compounds have emerged as promising molecules for Alzheimer's disease therapy.

α7nAchR/NMDAR coupling affects NMDAR function and object recognition.

PubMed

Li, Shupeng; Nai, Qiang; Lipina, Tatiana V; Roder, John C; Liu, Fang

2013-12-20

The α7 nicotinic acetylcholine receptor (nAchR) and NMDA glutamate receptor (NMDAR) are both ligand-gated ion channels permeable to Ca2+ and Na+. Previous studies have demonstrated functional modulation of NMDARs by nAchRs, although the molecular mechanism remains largely unknown. We have previously reported that α7nAchR forms a protein complex with the NMDAR through a protein-protein interaction. We also developed an interfering peptide that is able to disrupt the α7nAchR-NMDAR complex and blocks cue-induced reinstatement of nicotine-seeking in rat models of relapse. In the present study, we investigated whether the α7nAchR-NMDAR interaction is responsible for the functional modulation of NMDAR by α7nAchR using both electrophysiological and behavioral tests. We have found that activation of α7nAchR upregulates NMDAR-mediated whole cell currents and LTP of mEPSC in cultured hippocampal neurons, which can be abolished by the interfering peptide that disrupts the α7nAchR-NMDAR interaction. Moreover, administration of the interfering peptide in mice impairs novel object recognition but not Morris water maze performance. Our results suggest that α7nAchR/NMDAR coupling may selectively affect some aspects of learning and memory.

Generation of Recombinant Human AChE OP-Scavengers with Extended Circulatory Longevity

DTIC Science & Technology

2006-11-01

PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Avigdor Shafferman Ph.D. 5d. PROJECT NUMBER 5e. TASK NUMBER E-Mail: avigdor...glycans of rHuAChE, and in particular the distal termini of these glycan 8 projections , constitute a major factor in determining the circulatory...experiments funded by sources other than the USAMRMC contract, since they may have a major impact on the present project . Section III focuses on the

Distribution of intravenously administered acetylcholinesterase inhibitor and acetylcholinesterase activity in the adrenal gland: 11C-donepezil PET study in the normal rat.

PubMed

Watabe, Tadashi; Naka, Sadahiro; Ikeda, Hayato; Horitsugi, Genki; Kanai, Yasukazu; Isohashi, Kayako; Ishibashi, Mana; Kato, Hiroki; Shimosegawa, Eku; Watabe, Hiroshi; Hatazawa, Jun

2014-01-01

Acetylcholinesterase (AChE) inhibitors have been used for patients with Alzheimer's disease. However, its pharmacokinetics in non-target organs other than the brain has not been clarified yet. The purpose of this study was to evaluate the relationship between the whole-body distribution of intravenously administered (11)C-Donepezil (DNP) and the AChE activity in the normal rat, with special focus on the adrenal glands. The distribution of (11)C-DNP was investigated by PET/CT in 6 normal male Wistar rats (8 weeks old, body weight  = 220 ± 8.9 g). A 30-min dynamic scan was started simultaneously with an intravenous bolus injection of (11)C-DNP (45.0 ± 10.7 MBq). The whole-body distribution of the (11)C-DNP PET was evaluated based on the Vt (total distribution volume) by Logan-plot analysis. A fluorometric assay was performed to quantify the AChE activity in homogenized tissue solutions of the major organs. The PET analysis using Vt showed that the adrenal glands had the 2nd highest level of (11)C-DNP in the body (following the liver) (13.33 ± 1.08 and 19.43 ± 1.29 ml/cm(3), respectively), indicating that the distribution of (11)C-DNP was the highest in the adrenal glands, except for that in the excretory organs. The AChE activity was the third highest in the adrenal glands (following the small intestine and the stomach) (24.9 ± 1.6, 83.1 ± 3.0, and 38.5 ± 8.1 mU/mg, respectively), indicating high activity of AChE in the adrenal glands. We demonstrated the whole-body distribution of (11)C-DNP by PET and the AChE activity in the major organs by fluorometric assay in the normal rat. High accumulation of (11)C-DNP was observed in the adrenal glands, which suggested the risk of enhanced cholinergic synaptic transmission by the use of AChE inhibitors.

Structure-Based Design and Optimization of Multitarget-Directed 2H-Chromen-2-one Derivatives as Potent Inhibitors of Monoamine Oxidase B and Cholinesterases.

PubMed

Farina, Roberta; Pisani, Leonardo; Catto, Marco; Nicolotti, Orazio; Gadaleta, Domenico; Denora, Nunzio; Soto-Otero, Ramon; Mendez-Alvarez, Estefania; Passos, Carolina S; Muncipinto, Giovanni; Altomare, Cosimo D; Nurisso, Alessandra; Carrupt, Pierre-Alain; Carotti, Angelo

2015-07-23

The multifactorial nature of Alzheimer's disease calls for the development of multitarget agents addressing key pathogenic processes. To this end, by following a docking-assisted hybridization strategy, a number of aminocoumarins were designed, prepared, and tested as monoamine oxidases (MAOs) and acetyl- and butyryl-cholinesterase (AChE and BChE) inhibitors. Highly flexible N-benzyl-N-alkyloxy coumarins 2-12 showed good inhibitory activities at MAO-B, AChE, and BChE but low selectivity. More rigid inhibitors, bearing meta- and para-xylyl linkers, displayed good inhibitory activities and high MAO-B selectivity. Compounds 21, 24, 37, and 39, the last two featuring an improved hydrophilic/lipophilic balance, exhibited excellent activity profiles with nanomolar inhibitory potency toward hMAO-B, high hMAO-B over hMAO-A selectivity and submicromolar potency at hAChE. Cell-based assays of BBB permeation, neurotoxicity, and neuroprotection supported the potential of compound 37 as a BBB-permeant neuroprotective agent against H2O2-induced oxidative stress with poor interaction as P-gp substrate and very low cytotoxicity.

Evidence for a role for α6* nAChRs in L-dopa-induced dyskinesias using parkinsonian α6* nAChR gain-of-function mice

PubMed Central

Bordia, Tanuja; McGregor, Matthew; McIntosh, J.M.; Drenan, Ryan M.; Quik, Maryka

2015-01-01

L-Dopa-induced dyskinesias (LIDs) are a serious side effect of dopamine replacement therapy for Parkinson's disease. The mechanisms that underlie LIDs are currently unclear. However, preclinical studies indicate that nicotinic acetylcholine receptors (nAChRs) play a role, suggesting that drugs targeting these receptors may be of therapeutic benefit. To further understand the involvement of α6β2* nAChRs in LIDs, we used gain-of-function α6* nAChR (α6L9S) mice that exhibit a 20-fold enhanced sensitivity to nAChR agonists. Wildtype (WT) and α6L9S mice were lesioned by unilateral injection of 6-hydroxydopamine (6-OHDA, 3 μg/ml) into the medial forebrain bundle. Three to 4 wk later, they were administered L-dopa (3 mg/kg) plus benserazide (15 mg/kg) until stably dyskinetic. L-dopa-induced abnormal involuntary movements (AIMs) were similar in α6L9S and WT mice. WT mice were then given nicotine in the drinking water in gradually increasing doses to a final 300 μg/ml, which resulted in a 40% decline AIMs. By contrast, there was no decrease in AIMs in α6L9S mice at a maximally tolerated nicotine dose of 20 μg/ml. However, the nAChR antagonist mecamylamine (1 mg/kg ip 30 min before L-dopa) reduced L-dopa-induced AIMs in both α6L9S and WT mice. Thus, both a nAChR agonist and antagonist decreased AIMs in WT mice, but only the antagonist was effective in α6L9S mice. Since nicotine appears to reduce LIDs via desensitization, hypersensitive α6β2* nAChRs may desensitize less readily. The present data show that α6β2* nAChRs are key regulators of LIDs, and may be useful therapeutic targets for their management in Parkinson's disease. PMID:25813704

Nicotine suppresses the neurotoxicity by MPP+/MPTP through activating α7nAChR/PI3K/Trx-1 and suppressing ER stress.

PubMed

Cai, Yanxue; Zhang, Xianwen; Zhou, Xiaoshuang; Wu, Xiaoli; Li, Yanhui; Yao, Jianhua; Bai, Jie

2017-03-01

Parkinson's disease (PD) is a neurodegenerative disease. Nicotine has been reported to have the role in preventing Parkinson's disease. However, its mechanism is still unclear. In present study we found that nicotine suppressed 1-methyl-4-phenylpyridinium ion(MPP + ) toxicity in PC12 cells by MTT assay. The expression of thioredoxin-1(Trx-1) was decreased by MPP + , which was restored by nicotine. The nicotine suppressed expressions of Glucose-regulated protein 78(GRP78/Bip) and C/EBP homologous protein (CHOP) induced by MPP + . The methyllycaconitine (MLA), the inhibitor of α7nAChR and LY294002, the inhibitor of phosphatidylinositol 3-kinase (PI3K) blocked the suppressions of above molecules, respectively. Consistently, pretreatment with nicotine ameliorated the motor ability, restored the declines of Trx-1 and tyrosine hydroxylase (TH), and suppressed the expressions of Bip and CHOP induced by 1-Methy-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in mice. Our results suggest that nicotine plays role in resisting MPP + /MPTP neurotoxicity through activating the α7nAChR/PI3K/Trx-1 pathway and suppressing ER stress. Copyright © 2017 Elsevier B.V. All rights reserved.

Muscarinic ACh Receptors Contribute to Aversive Olfactory Learning in Drosophila.

PubMed

Silva, Bryon; Molina-Fernández, Claudia; Ugalde, María Beatriz; Tognarelli, Eduardo I; Angel, Cristian; Campusano, Jorge M

2015-01-01

The most studied form of associative learning in Drosophila consists in pairing an odorant, the conditioned stimulus (CS), with an unconditioned stimulus (US). The timely arrival of the CS and US information to a specific Drosophila brain association region, the mushroom bodies (MB), can induce new olfactory memories. Thus, the MB is considered a coincidence detector. It has been shown that olfactory information is conveyed to the MB through cholinergic inputs that activate acetylcholine (ACh) receptors, while the US is encoded by biogenic amine (BA) systems. In recent years, we have advanced our understanding on the specific neural BA pathways and receptors involved in olfactory learning and memory. However, little information exists on the contribution of cholinergic receptors to this process. Here we evaluate for the first time the proposition that, as in mammals, muscarinic ACh receptors (mAChRs) contribute to memory formation in Drosophila. Our results show that pharmacological and genetic blockade of mAChRs in MB disrupts olfactory aversive memory in larvae. This effect is not explained by an alteration in the ability of animals to respond to odorants or to execute motor programs. These results show that mAChRs in MB contribute to generating olfactory memories in Drosophila.

Muscarinic ACh Receptors Contribute to Aversive Olfactory Learning in Drosophila

PubMed Central

Silva, Bryon; Molina-Fernández, Claudia; Ugalde, María Beatriz; Tognarelli, Eduardo I.; Angel, Cristian; Campusano, Jorge M.

2015-01-01

The most studied form of associative learning in Drosophila consists in pairing an odorant, the conditioned stimulus (CS), with an unconditioned stimulus (US). The timely arrival of the CS and US information to a specific Drosophila brain association region, the mushroom bodies (MB), can induce new olfactory memories. Thus, the MB is considered a coincidence detector. It has been shown that olfactory information is conveyed to the MB through cholinergic inputs that activate acetylcholine (ACh) receptors, while the US is encoded by biogenic amine (BA) systems. In recent years, we have advanced our understanding on the specific neural BA pathways and receptors involved in olfactory learning and memory. However, little information exists on the contribution of cholinergic receptors to this process. Here we evaluate for the first time the proposition that, as in mammals, muscarinic ACh receptors (mAChRs) contribute to memory formation in Drosophila. Our results show that pharmacological and genetic blockade of mAChRs in MB disrupts olfactory aversive memory in larvae. This effect is not explained by an alteration in the ability of animals to respond to odorants or to execute motor programs. These results show that mAChRs in MB contribute to generating olfactory memories in Drosophila. PMID:26380118

Kinesin spindle protein (KSP) inhibitors. Part 7: Design and synthesis of 3,3-disubstituted dihydropyrazolobenzoxazines as potent inhibitors of the mitotic kinesin KSP.

PubMed

Garbaccio, Robert M; Tasber, Edward S; Neilson, Lou Anne; Coleman, Paul J; Fraley, Mark E; Olson, Christy; Bergman, Jeff; Torrent, Maricel; Buser, Carolyn A; Rickert, Keith; Walsh, Eileen S; Hamilton, Kelly; Lobell, Robert B; Tao, Weikang; South, Vicki J; Diehl, Ronald E; Davide, Joseph P; Yan, Youwei; Kuo, Lawrence C; Li, Chunze; Prueksaritanont, Thomayant; Fernandez-Metzler, Carmen; Mahan, Elizabeth A; Slaughter, Donald E; Salata, Joseph J; Kohl, Nancy E; Huber, Hans E; Hartman, George D

2007-10-15

Observations from two structurally related series of KSP inhibitors led to the proposal and discovery of dihydropyrazolobenzoxazines that possess ideal properties for cancer drug development. The synthesis and characterization of this class of inhibitors along with relevant pharmacokinetic and in vivo data are presented. The synthesis is highlighted by a key [3+2] cycloaddition to form the pyrazolobenzoxazine core followed by diastereospecific installation of a quaternary center.

An easy method for the determination of active concentrations of cholinesterase reactivators in blood samples: Application to the efficacy assessment of non quaternary reactivators compared to HI-6 and pralidoxime in VX-poisoned mice.

PubMed

Calas, André-Guilhem; Dias, José; Rousseau, Catherine; Arboléas, Mélanie; Touvrey-Loiodice, Mélanie; Mercey, Guillaume; Jean, Ludovic; Renard, Pierre-Yves; Nachon, Florian

2017-04-01

Organophosphorus nerve agents, like VX, are highly toxic due to their strong inhibition potency against acetylcholinesterase (AChE). AChE inhibited by VX can be reactivated using powerful nucleophilic molecules, most commonly oximes, which are one major component of the emergency treatment in case of nerve agent intoxication. We present here a comparative in vivo study on Swiss mice of four reactivators: HI-6, pralidoxime and two uncharged derivatives of 3-hydroxy-2-pyridinaldoxime that should more easily cross the blood-brain barrier and display a significant central nervous system activity. The reactivability kinetic profile of the oximes is established following intraperitoneal injection in healthy mice, using an original and fast enzymatic method based on the reactivation potential of oxime-containing plasma samples. HI-6 displays the highest reactivation potential whatever the conditions, followed by pralidoxime and the two non quaternary reactivators at the dose of 50 mg/kg bw. But these three last reactivators display equivalent reactivation potential at the same dose of 100 μmol/kg bw. Maximal reactivation potential closely correlates to surviving test results of VX intoxicated mice. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Quaternary prevention: reviewing the concept.

PubMed

Martins, Carlos; Godycki-Cwirko, Maciek; Heleno, Bruno; Brodersen, John

2018-12-01

According to the Wonca International Dictionary for General/Family Practice Quaternary Prevention is defined as: 'Action taken to identify patient at risk of overmedicalization, to protect him from new medical invasion, and to suggest to him interventions, which are ethically acceptable.' The concept of quaternary prevention was initially proposed by Marc Jamoulle and the targets were mainly patients with illness but without a disease. The purpose of this opinion article is to open the debate around a new possible definition and a new conceptual model of quaternary prevention based on the belief that quaternary prevention should be present in physicians' minds for every intervention they suggest to a patient. The debate around quaternary prevention is vital in the context of contemporary medicine and has expanded worldwide. The human being may suffer harm from medical interventions from conception, during their childhood, during their entire healthy lifetime as well as during a self-limited disease, a chronic disease, or a terminal disease. The current definition of quaternary prevention has limitations because it excludes patients and medical interventions where a quaternary prevention perspective would be needed and useful to protect patients from harm. In this context, a new definition and conceptual model of quaternary prevention is proposed. In this new proposal, quaternary prevention is defined as an 'action taken to protect individuals (persons/patients) from medical interventions that are likely to cause more harm than good.'

Quaternary prevention: reviewing the concept

PubMed Central

Martins, Carlos; Godycki-Cwirko, Maciek; Heleno, Bruno; Brodersen, John

2018-01-01

Abstract Background: According to the Wonca International Dictionary for General/Family Practice Quaternary Prevention is defined as: ‘Action taken to identify patient at risk of overmedicalization, to protect him from new medical invasion, and to suggest to him interventions, which are ethically acceptable.’ The concept of quaternary prevention was initially proposed by Marc Jamoulle and the targets were mainly patients with illness but without a disease. Objectives: The purpose of this opinion article is to open the debate around a new possible definition and a new conceptual model of quaternary prevention based on the belief that quaternary prevention should be present in physicians’ minds for every intervention they suggest to a patient. Discussion: The debate around quaternary prevention is vital in the context of contemporary medicine and has expanded worldwide. The human being may suffer harm from medical interventions from conception, during their childhood, during their entire healthy lifetime as well as during a self-limited disease, a chronic disease, or a terminal disease. The current definition of quaternary prevention has limitations because it excludes patients and medical interventions where a quaternary prevention perspective would be needed and useful to protect patients from harm. In this context, a new definition and conceptual model of quaternary prevention is proposed. Conclusion: In this new proposal, quaternary prevention is defined as an ‘action taken to protect individuals (persons/patients) from medical interventions that are likely to cause more harm than good.’ PMID:29384397

ACh-induced hyperpolarization and decreased resistance in mammalian type II vestibular hair cells.

PubMed

Poppi, Lauren A; Tabatabaee, Hessam; Drury, Hannah R; Jobling, Phillip; Callister, Robert J; Migliaccio, Americo A; Jordan, Paivi M; Holt, Joseph C; Rabbitt, Richard D; Lim, Rebecca; Brichta, Alan M

2018-01-01

In the mammalian vestibular periphery, electrical activation of the efferent vestibular system (EVS) has two effects on afferent activity: 1) it increases background afferent discharge and 2) decreases afferent sensitivity to rotational stimuli. Although the cellular mechanisms underlying these two contrasting afferent responses remain obscure, we postulated that the reduction in afferent sensitivity was attributed, in part, to the activation of α9- containing nicotinic acetylcholine (ACh) receptors (α9*nAChRs) and small-conductance potassium channels (SK) in vestibular type II hair cells, as demonstrated in the peripheral vestibular system of other vertebrates. To test this hypothesis, we examined the effects of the predominant EVS neurotransmitter ACh on vestibular type II hair cells from wild-type (wt) and α9-subunit nAChR knockout (α9 -/- ) mice. Immunostaining for choline acetyltransferase revealed there were no obvious gross morphological differences in the peripheral EVS innervation among any of these strains. ACh application onto wt type II hair cells, at resting potentials, produced a fast inward current followed by a slower outward current, resulting in membrane hyperpolarization and decreased membrane resistance. Hyperpolarization and decreased resistance were due to gating of SK channels. Consistent with activation of α9*nAChRs and SK channels, these ACh-sensitive currents were antagonized by the α9*nAChR blocker strychnine and SK blockers apamin and tamapin. Type II hair cells from α9 -/- mice, however, failed to respond to ACh at all. These results confirm the critical importance of α9nAChRs in efferent modulation of mammalian type II vestibular hair cells. Application of exogenous ACh reduces electrical impedance, thereby decreasing type II hair cell sensitivity. NEW & NOTEWORTHY Expression of α9 nicotinic subunit was crucial for fast cholinergic modulation of mammalian vestibular type II hair cells. These findings show a multifaceted

Influence of various force fields in estimating the binding affinity of acetylcholinesterase inhibitors using fast pulling of ligand scheme

NASA Astrophysics Data System (ADS)

Tam, Nguyen Minh; Vu, Khanh B.; Vu, Van V.; Ngo, Son Tung

2018-06-01

Acetylcholinesterase (AChE) is considered as one of the most favored drug targets for Alzheimer's disease. The effects of different force fields (FFs) on ranking affinity of acetylcholinesterase inhibitors were obtained using the fast pulling of ligand (FPL) method in steered-molecular dynamics (SMD) simulations. GROMOS, AMBER, CHARMM, and OPLS-AA FFs were investigated in this work. The pulling work derived with GROMOS FF has the strongest correlation and smallest error compared with experimental binding affinity. Moreover, the CPU consumption in the calculations using GROMOS FF is the lowest, which could allow us to rank affinity of a large number of AChE ligands.

Design, synthesis, biological evaluation and docking study of 5-oxo-4,5-dihydropyrano[3,2-c]chromene derivatives as acetylcholinesterase and butyrylcholinesterase inhibitors.

PubMed

Khoobi, Mehdi; Alipour, Masoumeh; Sakhteman, Amirhossein; Nadri, Hamid; Moradi, Alireza; Ghandi, Mehdi; Emami, Saeed; Foroumadi, Alireza; Shafiee, Abbas

2013-10-01

A series of fused coumarins namely 5-oxo-4,5-dihydropyrano[3,2-c]chromenes linked to N-benzylpyridinium scaffold were synthesized and evaluated as acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitors. The 1-(4-fluorobenzyl)pyridinium derivative 6g showed the most potent anti-AChE activity (IC50 value=0.038 μM) and the highest AChE/BuChE selectivity (SI>48). The docking study permitted us to rationalize the observed structure-affinity relationships and to detect possible binding modes. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Effects of inhibitors of acetylcholine synthesis on brain acetylcholine and survival in soman-intoxicated animals.

PubMed

Harris, L W; Stitcher, D L; Hey, W C

1982-05-31

The effects of hemicholinium-3 (HC-3) or 4-(l-naphthylvinyl)pyridine (4-NVP) alone and together with cholinolytics and/or cholinesterase inhibitors on brain acetylcholine (ACh) levels and survival were studied. Intracerebroventricular (ICVT) injection of 10 micrograms HC-3 280 min before euthanasia by microwave irradiation reduced rat cerebral ACh levels from 28.4 to 5.4 nmoles ACh/g wet tissue. In rats pretreated with HC-3 alone or with other pretreatment drugs prior to giving up to 2.7 LD50 of soman, iv, cerebral ACh levels increased very little, but in animals not receiving HC-3, brain ACh levels increased to 67.1 nmoles. Treatment of unpoisoned rats with 4-NVP resulted in a significant (26%) reduction in ACh. The inclusion of atropine with 4-NVP caused sign-free doses of physostigmine to produce toxic signs in rabbits and did not enhance the efficacy of carbamate pretreatment against soman. Pretreatment of rabbits with pyridostigmine and atropine methyl nitrate (AMN) failed to provide any protection against soman, but when HC-3, ICVT, was included with those drugs, the protective ratio (PR), against soman was increased excess ACh is a primary lesion in organophosphorus anticholinesterase intoxication and that the central nervous system is quite sensitive to excesses of ACh.

Myasthenia Gravis and the Tops and Bottoms of AChRs Antigenic Structure of the MIR and Specific Immunosuppression of EAMG Using AChR Cytoplasmic Domains

PubMed Central

Lindstrom, Jon; Luo, Jie; Kuryatov, Alexander

2009-01-01

The main immunogenic region (MIR), against which half or more of the autoantibodies to acetylcholine receptors (AChRs) in myasthenia gravis (MG) or experimental autoimmune MG (EAMG) are directed, is located at the extracellular end of α1 subunits. Rat monoclonal antibodies (mAbs) to the MIR efficiently compete with MG patient autoantibodies for binding to human muscle AChRs. Antibodies bound to the MIR do not interfere with cholinergic ligand binding or AChR function, but target complement and trigger antigenic modulation. Rat mAbs to the MIR also bind to human ganglionic AChR α3 subunits, but MG patient antibodies do not. By making chimeras of α1 subunits with α7 subunits or ACh binding protein, the structure of the MIR and its functional effects are being investigated. Many mAbs to the MIR bind only to the native conformation of α1 subunits because they bind to sequences that are adjacent only in the native structure. The MIR epitopes recognized by these mAbs are not recognized by most patient antibodies whose epitopes must be nearby. The presence of the MIR epitopes in α1/α7 chimeras greatly promotes AChR expression and sensitivity to activation. EAMG can be suppressed by treatment with denatured, bacterially expressed mixtures of extracellular and cytoplasmic domains of human α1, β1, γ, δ, and ε subunits. A mixture of only the cytoplasmic domains not only avoids the potential liability of provoking formation antibodies to pathologically significant epitopes on the extracellular surface, but also potently suppresses the development of EAMG. PMID:18567851

Analogs of methyllycaconitine as novel noncompetitive inhibitors of nicotinic receptors: pharmacological characterization, computational modeling, and pharmacophore development.

PubMed

McKay, Dennis B; Chang, Cheng; González-Cestari, Tatiana F; McKay, Susan B; El-Hajj, Raed A; Bryant, Darrell L; Zhu, Michael X; Swaan, Peter W; Arason, Kristjan M; Pulipaka, Aravinda B; Orac, Crina M; Bergmeier, Stephen C

2007-05-01

As a novel approach to drug discovery involving neuronal nicotinic acetylcholine receptors (nAChRs), our laboratory targeted nonagonist binding sites (i.e., noncompetitive binding sites, negative allosteric binding sites) located on nAChRs. Cultured bovine adrenal cells were used as neuronal models to investigate interactions of 67 analogs of methyllycaconitine (MLA) on native alpha3beta4* nAChRs. The availability of large numbers of structurally related molecules presents a unique opportunity for the development of pharmacophore models for noncompetitive binding sites. Our MLA analogs inhibited nicotine-mediated functional activation of both native and recombinant alpha3beta4* nAChRs with a wide range of IC(50) values (0.9-115 microM). These analogs had little or no inhibitory effects on agonist binding to native or recombinant nAChRs, supporting noncompetitive inhibitory activity. Based on these data, two highly predictive 3D quantitative structure-activity relationship (comparative molecular field analysis and comparative molecular similarity index analysis) models were generated. These computational models were successfully validated and provided insights into the molecular interactions of MLA analogs with nAChRs. In addition, a pharmacophore model was constructed to analyze and visualize the binding requirements to the analog binding site. The pharmacophore model was subsequently applied to search structurally diverse molecular databases to prospectively identify novel inhibitors. The rapid identification of eight molecules from database mining and our successful demonstration of in vitro inhibitory activity support the utility of these computational models as novel tools for the efficient retrieval of inhibitors. These results demonstrate the effectiveness of computational modeling and pharmacophore development, which may lead to the identification of new therapeutic drugs that target novel sites on nAChRs.

7-MEOTA-donepezil like compounds as cholinesterase inhibitors: Synthesis, pharmacological evaluation, molecular modeling and QSAR studies.

PubMed

Korabecny, Jan; Dolezal, Rafael; Cabelova, Pavla; Horova, Anna; Hruba, Eva; Ricny, Jan; Sedlacek, Lukas; Nepovimova, Eugenie; Spilovska, Katarina; Andrs, Martin; Musilek, Kamil; Opletalova, Veronika; Sepsova, Vendula; Ripova, Daniela; Kuca, Kamil

2014-07-23

A novel series of 7-methoxytacrine (7-MEOTA)-donepezil like compounds was synthesized and tested for their ability to inhibit electric eel acetylcholinesterase (EeAChE), human recombinant AChE (hAChE), equine serum butyrylcholinesterase (eqBChE) and human plasmatic BChE (hBChE). New hybrids consist of a 7-MEOTA unit, representing less toxic tacrine (THA) derivative, connected with analogues of N-benzylpiperazine moieties mimicking N-benzylpiperidine fragment from donepezil. 7-MEOTA-donepezil like compounds exerted mostly non-selective profile in inhibiting cholinesterases of different origin with IC50 ranging from micromolar to sub-micromolar concentration scale. Kinetic analysis confirmed mixed-type inhibition presuming that these inhibitors are capable to simultaneously bind peripheral anionic site (PAS) as well as catalytic anionic site (CAS) of AChE. Molecular modeling studies and QSAR studies were performed to rationalize studies from in vitro. Overall, 7-MEOTA-donepezil like derivatives can be considered as interesting candidates for Alzheimer's disease treatment. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

[Women's approach to childhood toothache, abdominal ache and earache].

PubMed

Efe, Emine; Öncel, Selma; Yilmaz, Mualla

2012-01-01

This study was conducted to determine women's about attitudes child's teeth, abdomen and ear ache. Those who had lived in Antalya that 6 number primary health care center between March-May 2004 were enrolled in the study. As data collecting tools. A questionnaire prepared by the authors. This study was determined that 29.2 % of the mothers carried out mixture who had prepared at home to child's abdomen and foot base; 30.3 % were to put breast milk childs' ear; 38.9 % were placed aspirin, salt and salts of lemon to childs' teeth ache. The majority of the women make a wrong practices child that teeth, abdomen and ear ache. This traditional practice effecting factors were the women's educational status and age. The results of the study that education about child care, common health problems and incorrect applications shoud be given to women by nurse.

Novel Quaternary Quantum Decoder, Multiplexer and Demultiplexer Circuits

NASA Astrophysics Data System (ADS)

Haghparast, Majid; Monfared, Asma Taheri

2017-05-01

Multiple valued logic is a promising approach to reduce the width of the reversible or quantum circuits, moreover, quaternary logic is considered as being a good choice for future quantum computing technology hence it is very suitable for the encoded realization of binary logic functions through its grouping of 2-bits together into quaternary values. The Quaternary decoder, multiplexer, and demultiplexer are essential units of quaternary digital systems. In this paper, we have initially designed a quantum realization of the quaternary decoder circuit using quaternary 1-qudit gates and quaternary Muthukrishnan-Stroud gates. Then we have presented quantum realization of quaternary multiplexer and demultiplexer circuits using the constructed quaternary decoder circuit and quaternary controlled Feynman gates. The suggested circuits in this paper have a lower quantum cost and hardware complexity than the existing designs that are currently used in quaternary digital systems. All the scales applied in this paper are based on Nanometric area.

Synthesis, biological evaluation and docking studies of 2,3-dihydroquinazolin-4(1H)-one derivatives as inhibitors of cholinesterases.

PubMed

Sarfraz, Muhammad; Sultana, Nargis; Rashid, Umer; Akram, Muhammad Safwan; Sadiq, Abdul; Tariq, Muhammad Ilyas

2017-02-01

In search of potent inhibitors of cholinesterases, we have synthesized and evaluate a number of 2,3-dihydroquinazolin-4(1H)-one derivatives. The synthetic approach provided an efficient synthesis of the target molecules with excellent yield. All the tested compounds showed activity against both the enzymes in micromolar range. In many case, the inhibition of both enzymes are higher than or comparable to the standard drug galatamine. With the selectivity index of 2.3 for AChE, compound 5f can be considered as a potential lead compound with a feature of dual AChE/BChE inhibition with IC 50 =1.6±0.10μM (AChE) and 3.7±0.18μM (BChE). Binding modes of the synthesized compounds were explored by using GOLD (Genetic Optimization for Ligand Docking) suit v5.4.1. The computed binding modes of these compounds in the active site of AChE and BChE provide an insight into the mechanism of inhibition of these two enzyme. Copyright © 2017 Elsevier Inc. All rights reserved.

Identification of potential herbal inhibitor of acetylcholinesterase associated Alzheimer's disorders using molecular docking and molecular dynamics simulation.

PubMed

Seniya, Chandrabhan; Khan, Ghulam Jilani; Uchadia, Kuldeep

2014-01-01

Cholinesterase inhibitors (ChE-Is) are the standard for the therapy of AD associated disorders and are the only class of approved drugs by the Food and Drug Administration (FDA). Additionally, acetylcholinesterase (AChE) is the target for many Alzheimer's dementia drugs which block the function of AChE but have some side effects. Therefore, in this paper, an attempt was made to elucidate cholinesterase inhibition potential of secondary metabolite from Cannabis plant which has negligible or no side effect. Molecular docking of 500 herbal compounds, against AChE, was performed using Autodock 4.2 as per the standard protocols. Molecular dynamics simulations have also been carried out to check stability of binding complex in water for 1000 ps. Our molecular docking and simulation have predicted high binding affinity of secondary metabolite (C28H34N2O6) to AChE. Further, molecular dynamics simulations for 1000 ps suggest that ligand interaction with the residues Asp72, Tyr70-121-334, and Phe288 of AChE, all of which fall under active site/subsite or binding pocket, might be critical for the inhibitory activity of AChE. This approach might be helpful to understand the selectivity of the given drug molecule in the treatment of Alzheimer's disease. The study provides evidence for consideration of C28H34N2O6 as a valuable small ligand molecule in treatment and prevention of AD associated disorders and further in vitro and in vivo investigations may prove its therapeutic potential.

Identification of Potential Herbal Inhibitor of Acetylcholinesterase Associated Alzheimer's Disorders Using Molecular Docking and Molecular Dynamics Simulation

PubMed Central

Seniya, Chandrabhan; Khan, Ghulam Jilani; Uchadia, Kuldeep

2014-01-01

Cholinesterase inhibitors (ChE-Is) are the standard for the therapy of AD associated disorders and are the only class of approved drugs by the Food and Drug Administration (FDA). Additionally, acetylcholinesterase (AChE) is the target for many Alzheimer's dementia drugs which block the function of AChE but have some side effects. Therefore, in this paper, an attempt was made to elucidate cholinesterase inhibition potential of secondary metabolite from Cannabis plant which has negligible or no side effect. Molecular docking of 500 herbal compounds, against AChE, was performed using Autodock 4.2 as per the standard protocols. Molecular dynamics simulations have also been carried out to check stability of binding complex in water for 1000 ps. Our molecular docking and simulation have predicted high binding affinity of secondary metabolite (C28H34N2O6) to AChE. Further, molecular dynamics simulations for 1000 ps suggest that ligand interaction with the residues Asp72, Tyr70-121-334, and Phe288 of AChE, all of which fall under active site/subsite or binding pocket, might be critical for the inhibitory activity of AChE. This approach might be helpful to understand the selectivity of the given drug molecule in the treatment of Alzheimer's disease. The study provides evidence for consideration of C28H34N2O6 as a valuable small ligand molecule in treatment and prevention of AD associated disorders and further in vitro and in vivo investigations may prove its therapeutic potential. PMID:25054066

PKCε phosphorylates α4β2 nicotinic ACh receptors and promotes recovery from desensitization

PubMed Central

Lee, A M; Wu, D-F; Dadgar, J; Wang, D; McMahon, T; Messing, R O

2015-01-01

Background and Purpose Nicotinic (ACh) receptor recovery from desensitization is modulated by PKC, but the PKC isozymes and the phosphorylation sites involved have not been identified. We investigated whether PKCε phosphorylation of α4β2 nAChRs regulates receptor recovery from desensitization. Experimental Approach Receptor recovery from desensitization was investigated by electrophysiological characterization of human α4β2 nAChRs. Phosphorylation of the α4 nAChR subunit was assessed by immunoblotting of mouse synaptosomes. Hypothermia induced by sazetidine-A and nicotine was measured in Prkce−/− and wild-type mice. Key Results Inhibiting PKCε impaired the magnitude of α4β2 nAChR recovery from desensitization. We identified five putative PKCε phosphorylation sites in the large intracellular loop of the α4 subunit, and mutating four sites to alanines also impaired recovery from desensitization. α4 nAChR subunit phosphorylation was reduced in synaptosomes from Prkce−/− mice. Sazetidine-A-induced hypothermia, which is mediated by α4β2 nAChR desensitization, was more severe and prolonged in Prkce−/− than in wild-type mice. Conclusions and Implications PKCε phosphorylates the α4 nAChR subunit and regulates recovery from receptor desensitization. This study illustrates the importance of phosphorylation in regulating α4β2 receptor function, and suggests that reducing phosphorylation prolongs receptor desensitization and decreases the number of receptors available for activation. PMID:26103136

31 CFR 363.38 - What happens if my financial institution returns an ACH debit?

Code of Federal Regulations, 2010 CFR

2010-07-01

... TreasuryDirect § 363.38 What happens if my financial institution returns an ACH debit? If your designated financial institution returns an ACH debit, we reserve the right to reinitiate the debit at our option. We.... We are not responsible for any fees your financial institution may charge relating to returned ACH...

Synthesis, biological assessment and molecular modeling of new dihydroquinoline-3-carboxamides and dihydroquinoline-3-carbohydrazide derivatives as cholinesterase inhibitors, and Ca channel antagonists.

PubMed

Tomassoli, Isabelle; Ismaili, Lhassane; Pudlo, Marc; de Los Ríos, Cristóbal; Soriano, Elena; Colmena, Inés; Gandía, Luis; Rivas, Luis; Samadi, Abdelouahid; Marco-Contelles, José; Refouvelet, Bernard

2011-01-01

The synthesis, biological evaluation, and molecular modeling of new 4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxamides(4), 4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carbohydrazide (6), and some hexahydropyrimido[5,4-c]quinoline-2,5-diones (9) produced earlier by our laboratory, as AChE/BuChE inhibitors, is described. From these analyses compound 4c resulted equipotent regarding the inhibition of cholinesterases'; inhibitors 6k, 9a, 9b were selective for AChE, whereas product 4d proved selective for BuChE. Docking analysis has been carry out in order to identify the binding mode in the active site, and to explain the observed selectivities. Only compound 9a has been shown to decrease K(+)-induced calcium signals in bovine chromaffin cells. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

Crystal structures of Lymnaea stagnalis AChBP in complex with neonicotinoid insecticides imidacloprid and clothianidin

PubMed Central

Ihara, Makoto; Okajima, Toshihide; Yamashita, Atsuko; Oda, Takuma; Hirata, Koichi; Nishiwaki, Hisashi; Morimoto, Takako; Akamatsu, Miki; Ashikawa, Yuji; Kuroda, Shun’ichi; Mega, Ryosuke; Kuramitsu, Seiki; Sattelle, David B.

2008-01-01

Neonicotinoid insecticides, which act on nicotinic acetylcholine receptors (nAChRs) in a variety of ways, have extremely low mammalian toxicity, yet the molecular basis of such actions is poorly understood. To elucidate the molecular basis for nAChR–neonicotinoid interactions, a surrogate protein, acetylcholine binding protein from Lymnaea stagnalis (Ls-AChBP) was crystallized in complex with neonicotinoid insecticides imidacloprid (IMI) or clothianidin (CTD). The crystal structures suggested that the guanidine moiety of IMI and CTD stacks with Tyr185, while the nitro group of IMI but not of CTD makes a hydrogen bond with Gln55. IMI showed higher binding affinity for Ls-AChBP than that of CTD, consistent with weaker CH–π interactions in the Ls-AChBP–CTD complex than in the Ls-AChBP–IMI complex and the lack of the nitro group-Gln55 hydrogen bond in CTD. Yet, the NH at position 1 of CTD makes a hydrogen bond with the backbone carbonyl of Trp143, offering an explanation for the diverse actions of neonicotinoids on nAChRs. PMID:18338186

Neurotoxicity fingerprinting of venoms using on-line microfluidic AChBP profiling.

PubMed

Slagboom, Julien; Otvos, Reka A; Cardoso, Fernanda C; Iyer, Janaki; Visser, Jeroen C; van Doodewaerd, Bjorn R; McCleary, Ryan J R; Niessen, Wilfried M A; Somsen, Govert W; Lewis, Richard J; Kini, R Manjunatha; Smit, August B; Casewell, Nicholas R; Kool, Jeroen

2018-06-15

Venoms from snakes are rich sources of highly active proteins with potent affinity towards a variety of enzymes and receptors. Of the many distinct toxicities caused by envenomation, neurotoxicity plays an important role in the paralysis of prey by snakes as well as by venomous sea snails and insects. In order to improve the analytical discovery component of venom toxicity profiling, this paper describes the implementation of microfluidic high-resolution screening (HRS) to obtain neurotoxicity fingerprints from venoms that facilitates identification of the neurotoxic components of envenomation. To demonstrate this workflow, 47 snake venoms were profiled using the acetylcholine binding protein (AChBP) to mimic the target of neurotoxic proteins, in particular nicotinic acetylcholine receptors (nAChRs). In the microfluidic HRS system, nanoliquid chromatographic (nanoLC) separations were on-line connected to both AChBP profiling and parallel mass spectrometry (MS). For virtually all neurotoxic elapid snake venoms tested, we obtained bioactivity fingerprints showing major and minor bioactive zones containing masses consistent with three-finger toxins (3FTxs), whereas, viperid and colubrid venoms showed little or no detectable bioactivity. Our findings demonstrate that venom interactions with AChBP correlate with the severity of neurotoxicity observed following human envenoming by different snake species. We further, as proof of principle, characterized bioactive venom peptides from a viperid (Daboia russelli) and an elapid (Aspidelaps scutatus scutatus) snake by nanoLC-MS/MS, revealing that different toxin classes interact with the AChBP, and that this binding correlates with the inhibition of α7-nAChR in calcium-flux cell-based assays. The on-line post-column binding assay and subsequent toxin characterization methodologies described here provide a new in vitro analytic platform for rapidly investigating neurotoxic snake venom proteins. Copyright © 2018 The Author

Extracts and constituents of Leontopodium alpinum enhance cholinergic transmission: Brain ACh increasing and memory improving properties

PubMed Central

Hornick, Ariane; Schwaiger, Stefan; Rollinger, Judith M.; Vo, Nguyen Phung; Prast, Helmut; Stuppner, Hermann

2012-01-01

Leontopodium alpinum (‘Edelweiss’) was phytochemically investigated for constituents that might enhance cholinergic neurotransmission. The potency to increase synaptic availability of acetylcholine (ACh) in rat brain served as key property for the bioguided isolation of cholinergically active compounds using different chromatographic techniques. The dichlormethane (DCM) extract of the root, fractions and isolated constituents were injected i.c.v. and the effect on brain ACh was detected via the push–pull technique. The DCM extract enhanced extracellular ACh concentration in rat brain and inhibited acetylcholinesterase (AChE) in vitro. The extracellular level of brain ACh was significantly increased by the isolated sesquiterpenes, isocomene and 14-acetoxyisocomene, while silphiperfolene acetate and silphinene caused a small increasing tendency. Only silphiperfolene acetate showed in vitro AChE inhibitory activity, thus suggesting the other sesquiterpenes to stimulate cholinergic transmission by an alternative mechanism of action. Isocomene was further investigated with behavioural tasks in mice. It restored object recognition in scopolamine-impaired mice and showed nootropic effects in the T-maze alternation task in normal and scopolamine-treated mice. Additionally, this sesquiterpene reduced locomotor activity of untreated mice in the open field task, while the activity induced by scopolamine was abolished. The enhancement of synaptic availability of ACh, the promotion of alternation, and the amelioration of scopolamine-induced deficit are in accordance with a substance that amplifies cholinergic transmission. Whether the mechanism of action is inhibition of AChE or another pro-cholinergic property remains to be elucidated. Taken together, isocomene and related constituents of L. alpinum deserve further interest as potential antidementia agents in brain diseases associated with cholinergic deficits. PMID:18541221

Modulation of hippocampal ACh release by chronic nicergoline treatment in freely moving young and aged rats.

PubMed

Carfagna, N; Di Clemente, A; Cavanus, S; Damiani, D; Gerna, M; Salmoiraghi, P; Cattaneo, B; Post, C

1995-09-15

The effects of nicergoline on basal and K(+)-stimulated release of ACh in the hippocampus of 3- and 19-month old rats has been studied by microdialysis. A significant decrease of basal ACh release (59%) was found in aged vehicle treated rats in comparison to young rats. High-K+ (100 mM) in the perfusate strongly increased the release of ACh by up to 6-fold over the baseline of both young and aged rats. Chronic oral administration of nicergoline to aged rats (5 mg/kg b.i.d. for 6 weeks) significantly reversed (93%) the age-related decrease of basal release of ACh, leaving the increase due to K+ depolarization unchanged. In young animals, nicergoline did not affect the basal output of ACh, but enhanced the K(+)-evoked release of ACh by 39%. Results from this study demonstrate that nicergoline treatment increases the ability of hippocampal cholinergic terminals to release ACh, and suggest that this drug can reset the cholinergic impairement associated with aging.

Gold nanoclusters-Cu(2+) ensemble-based fluorescence turn-on and real-time assay for acetylcholinesterase activity and inhibitor screening.

PubMed

Sun, Jian; Yang, Xiurong

2015-12-15

Based on the specific binding of Cu(2+) ions to the 11-mercaptoundecanoic acid (11-MUA)-protected AuNCs with intense orange-red emission, we have proposed and constructed a novel fluorescent nanomaterials-metal ions ensemble at a nonfluorescence off-state. Subsequently, an AuNCs@11-MUA-Cu(2+) ensemble-based fluorescent chemosensor, which is amenable to convenient, sensitive, selective, turn-on and real-time assay of acetylcholinesterase (AChE), could be developed by using acetylthiocholine (ATCh) as the substrate. Herein, the sensing ensemble solution exhibits a marvelous fluorescent enhancement in the presence of AChE and ATCh, where AChE hydrolyzes its active substrate ATCh into thiocholine (TCh), and then TCh captures Cu(2+) from the ensemble, accompanied by the conversion from fluorescence off-state to on-state of the AuNCs. The AChE activity could be detected less than 0.05 mU/mL within a good linear range from 0.05 to 2.5 mU/mL. Our proposed fluorescence assay can be utilized to evaluate the AChE activity quantitatively in real biological sample, and furthermore to screen the inhibitor of AChE. As far as we know, the present study has reported the first analytical proposal for sensing AChE activity in real time by using a fluorescent nanomaterials-Cu(2+) ensemble or focusing on the Cu(2+)-triggered fluorescence quenching/recovery. This strategy paves a new avenue for exploring the biosensing applications of fluorescent AuNCs, and presents the prospect of AuNCs@11-MUA-Cu(2+) ensemble as versatile enzyme activity assay platforms by means of other appropriate substrates/analytes. Copyright © 2015 Elsevier B.V. All rights reserved.

Comparison of GPS and Quaternary slip rates: Insights from a new Quaternary fault database for Central Asia

NASA Astrophysics Data System (ADS)

Mohadjer, Solmaz; Ehlers, Todd; Bendick, Rebecca; Mutz, Sebastian

2016-04-01

Previous studies related to the kinematics of deformation within the India-Asia collision zone have relied on slip rate data for major active faults to test kinematic models that explain the deformation of the region. The slip rate data, however, are generally disputed for many of the first-order faults in the region (e.g., Altyn Tagh and Karakorum faults). Several studies have also challenged the common assumption that geodetic slip rates are representative of Quaternary slip rates. What has received little attention is the degree to which geodetic slip rates relate to Quaternary slip rates for active faults in the India-Asia collision zone. In this study, we utilize slip rate data from a new Quaternary fault database for Central Asia to determine the overall relationship between Quaternary and GPS-derived slip rates for 18 faults. The preliminary analysis investigating this relationship uses weighted least squares and a re-sampling analysis to test the sensitivity of this relationship to different data point attributes (e.g., faults associated with data points and dating methods used for estimating Quaternary slip rates). The resulting sample subsets of data points yield a maximum possible Pearson correlation coefficient of ~0.6, suggesting moderate correlation between Quaternary and GPS-derived slip rates for some faults (e.g., Kunlun and Longmen Shan faults). Faults with poorly correlated Quaternary and GPS-derived slip rates were identified and dating methods used for the Quaternary slip rates were examined. Results indicate that a poor correlation between Quaternary and GPS-derived slip rates exist for the Karakorum and Chaman faults. Large differences between Quaternary and GPS slip rates for these faults appear to be connected to qualitative dating of landforms used in the estimation of the Quaternary slip rates and errors in the geomorphic and structural reconstruction of offset landforms (e.g., offset terrace riser reconstructions for Altyn Tagh fault

Synthesis, biological assessment and molecular modeling of new multipotent MAO and cholinesterase inhibitors as potential drugs for the treatment of Alzheimer's disease.

PubMed

Samadi, Abdelouahid; Chioua, Mourad; Bolea, Irene; de Los Ríos, Cristóbal; Iriepa, Isabel; Moraleda, Ignacio; Bastida, Agatha; Esteban, Gerard; Unzeta, Mercedes; Gálvez, Enrique; Marco-Contelles, José

2011-09-01

The synthesis, biological evaluation and molecular modeling of new multipotent inhibitors of type I and type II, able to simultaneously inhibit monoamine oxidases (MAO) as well as acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), is described. Compounds of type I were prepared by sequential reaction of 2,6-dichloro-4-phenylpyridine-3,5-dicarbonitrile (14) [or 2,6-dichloropyridine-3,5-dicarbonitrile (15)] with prop-2-yn-1-amine (or N-methylprop-2-yn-1-amine) and 2-(1-benzyl-piperidin-4-yl)alkylamines 22-25. Compounds of type II were prepared by Friedländer type reaction of 6-amino-5-formyl-2-(methyl(prop-2-yn-1-yl)amino)nicotinonitriles 32 and 33 with 4-(1-benzylpiperidin-4-yl)butan-2-one (31). The biological evaluation of molecules 1-11 showed that most of these compounds are potent, in the nanomolar range, and selective AChEI, with moderate and equipotent selectivity for MAO-A and MAO-B inhibition. Kinetic studies of compound 8 proved that this is a EeAChE mixed type inhibitor (IC(50) = 16 ± 2; Ki = 12 ± 3 nM). Molecular modeling investigation on compound 8 confirmed its dual AChE inhibitory profile, binding simultaneously at the catalytic active site (CAS) and at the peripheric anionic site (PAS). In overall, compound 11, as a potent and selective dual AChEI, showing a moderate and selective MAO-A inhibitory profile, can be considered as an attractive multipotent drug for further development on two key pharmacological targets playing key roles in the therapy of Alzheimer's disease. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Pharmacological and immunochemical characterization of α2* nicotinic acetylcholine receptors (nAChRs) in mouse brain

PubMed Central

Whiteaker, Paul; Wilking, Jennifer A; Brown, Robert WB; Brennan, Robert J; Collins, Allan C; Lindstrom, Jon M; Boulter, Jim

2009-01-01

Aim: α2 nAChR subunit mRNA expression in mice is most intense in the olfactory bulbs and interpeduncular nucleus. We aimed to investigate the properties of α2* nAChRs in these mouse brain regions. Methods: α2 nAChR subunit-null mutant mice were engineered. Pharmacological and immunoprecipitation studies were used to determine the composition of α2 subunit-containing (α2*) nAChRs in these two regions. Results: [125I]Epibatidine (200 pmol/L) autoradiography and saturation binding demonstrated that α2 deletion reduces nAChR expression in both olfactory bulbs and interpeduncular nucleus (by 4.8±1.7 and 92±26 fmol̇mg-1 protein, respectively). Pharmacological characterization using the β2-selective drug A85380 to inhibit [125I]epibatidine binding proved inconclusive, so immunoprecipitation methods were used to further characterize α2* nAChRs. Protocols were established to immunoprecipitate β2 and β4 nAChRs. Immunoprecipitation specificity was ascertained using tissue from β2- and β4-null mutant mice, and efficacy was good (>90% of β2* and >80% of β4* nAChRs were routinely recovered). Conclusion: Immunoprecipitation experiments indicated that interpeduncular nucleus α2* nAChRs predominantly contain β2 subunits, while those in olfactory bulbs contain mainly β4 subunits. In addition, the immunoprecipitation evidence indicated that both nuclei, but especially the interpeduncular nucleus, express nAChR complexes containing both β2 and β4 subunits. PMID:19498420

Design, synthesis and biological activity of novel donepezil derivatives bearing N-benzyl pyridinium moiety as potent and dual binding site acetylcholinesterase inhibitors.

PubMed

Lan, Jin-Shuai; Zhang, Tong; Liu, Yun; Yang, Jing; Xie, Sai-Sai; Liu, Jing; Miao, Ze-Yang; Ding, Yue

2017-06-16

A series of new donepezil derivatives were designed synthesized and evaluated as multifunctional cholinesterase inhibitors against Alzheimer's disease (AD). In vitro studies showed that most of them exhibited significant potency to inhibit acetylcholinesterase and self-induced β-amyloid (Aβ) aggregation, and moderate antioxidant activity. Especially, compound 5b presented the greatest ability to inhibit cholinesterase (IC 50 , 1.9 nM for eeAChE and 0.8 nM for hAChE), good inhibition of Aβ aggregation (53.7% at 20 μM) and good antioxidant activity (0.54 trolox equivalents). Kinetic and molecular modeling studies indicated that compound 5b was a mixed-type inhibitor, binding simultaneously to the catalytic active site (CAS) and the peripheral anionic site (PAS) of AChE. In addition, compound 5b could reduce PC12 cells death induced by oxidative stress and Aβ (1-42). Moreover, in vivo experiments showed that compound 5b was nontoxic and tolerated at doses up to 2000 mg/kg. These results suggested that compound 5b might be an excellent multifunctional agent for AD treatment. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Biochemical effects of glyphosate based herbicide, Excel Mera 71 on enzyme activities of acetylcholinesterase (AChE), lipid peroxidation (LPO), catalase (CAT), glutathione-S-transferase (GST) and protein content on teleostean fishes.

PubMed

Samanta, Palas; Pal, Sandipan; Mukherjee, Aloke Kumar; Ghosh, Apurba Ratan

2014-09-01

Effects of glyphosate based herbicide, Excel Mera 71 at a dose of 17.20mg/l on enzyme activities of acetylcholinesterase (AChE), lipid peroxidation (LPO), catalase (CAT), glutathione-S-transferase (GST) and protein content were measured in different tissues of two Indian air-breathing teleosts, Anabas testudineus (Bloch) and Heteropneustes fossilis (Bloch) during an exposure period of 30 days under laboratory condition. AChE activity was significantly increased in all the investigated tissues of both fish species and maximum elevation was observed in brain of H. fossilis, while spinal cord of A. testudineus showed minimum increment. Fishes showed significant increase LPO levels in all the tissues; highest was observed in gill of A. testudineus but lowest LPO level was observed in muscle of H. fossilis. CAT was also enhanced in both the fishes, while GST activity in liver diminished substantially and minimum was observed in liver of A. testudineus. Total protein content showed decreased value in all the tissues, maximum reduction was observed in liver and minimum in brain of A. testudineus and H. fossilis respectively. The results indicated that Excel Mera 71 caused serious alterations in the enzyme activities resulting into severe deterioration of fish health; so, AChE, LPO, CAT and GST can be used as suitable indicators of herbicidal toxicity. Copyright © 2014 Elsevier Inc. All rights reserved.

Synthesis and in vitro evaluation of new derivatives of 2-substituted-6-fluorobenzo[d]thiazoles as cholinesterase inhibitors.

PubMed

Imramovský, Aleš; Pejchal, Vladimír; Štěpánková, Šárka; Vorčáková, Katarína; Jampílek, Josef; Vančo, Ján; Šimůnek, Petr; Královec, Karel; Brůčková, Lenka; Mandíková, Jana; Trejtnar, František

2013-04-01

A series of novel cholinesterase inhibitors based on 2-substituted 6-fluorobenzo[d]thiazole were synthesised and characterised by IR, (1)H, (13)C and (19)F NMR spectroscopy and HRMS. Purity was checked by elemental analyses. The novel carbamates were tested for their ability to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). The toxicity of the most active compounds was investigated using a standard in vitro test with HepG2 cells, and the ratio between biological activity and toxicity was determined. In addition, the toxicity of the most active compounds was evaluated against MCF7 cells using the xCELLigence system. Structure-activity relationships reflecting the dependence of cholinesterase inhibitors on the lipophilicity of the compounds as well as on the Taft polar and steric substituent constants are discussed. The specific orientation of the inhibitors in the binding site of acetylcholinesterase was determined using molecular docking of the most active compound. Copyright © 2013 Elsevier Ltd. All rights reserved.

Regulation of ACh release from guinea pig bladder urothelial cells: potential role in bladder filling sensations.

PubMed

McLatchie, L M; Young, J S; Fry, C H

2014-07-01

The aim of this study was to quantify and characterize the mechanism of non-neuronal ACh release from bladder urothelial cells and to determine if urothelial cells could be a site of action of anti-muscarinic drugs. A novel technique was developed whereby ACh could be measured from freshly isolated guinea pig urothelial cells in suspension following mechanical stimulation. Various agents were used to manipulate possible ACh release pathways in turn and to study the effects of muscarinic receptor activation and inhibition on urothelial ATP release. Minimal mechanical stimulus achieved full ACh release, indicating a small dynamic range and possible all-or-none signal. ACh release involved a mechanism dependent on the anion channel CFTR and intracellular calcium concentration, but was independent of extracellular calcium, vesicular trafficking, connexins or pannexins, organic cation transporters and was not affected by botulinum-A toxin. Stimulating ACh receptors increased ATP production and antagonizing them reduced ATP release, suggesting a link between ACh and ATP release. These results suggest that release of non-neuronal ACh from the urothelium is large enough and well located to act as a modulator of ATP release. It is hypothesized that this pathway may contribute to the actions of anti-muscarinic drugs in reducing the symptoms of lower urinary tract syndromes. Additionally the involvement of CFTR in ACh release suggests an exciting new direction for the treatment of these conditions. © 2014 The British Pharmacological Society.

Phytochemical and ethnomedicinal study of Huperzia species used in the traditional medicine of Saraguros in Southern Ecuador; AChE and MAO inhibitory activity.

PubMed

Armijos, Chabaco; Gilardoni, Gianluca; Amay, Luis; Lozano, Antonio; Bracco, Francesco; Ramirez, Jorge; Bec, Nicole; Larroque, Christian; Finzi, Paola Vita; Vidari, Giovanni

2016-12-04

This study concerns seven Huperzia species (Lycopodiaceae), namely H. brevifolia, H. columnaris, H. compacta, H. crassa, H. espinosana, H. tetragona, H. weberbaueri, which are considered sacred plants by the Saraguro community, living in the Southern Andes of Ecuador; these plants are widely used in traditional medicine and ritual ceremonies. The plants were selected on the basis of written interviews with 10 visionary healers (yachak) (2 women, 8 men), indicated as the most credible by the Saraguro Healers Council. The Informant Consensus Factor (F ic ) was determined. The first phytochemical study of the plants was performed by standard procedures, while the AChE and MAO-A inhibition by fractions enriched in high MW alkaloids, was measured in vitro. i) to investigate the uses of some Huperzia plants in healing and magical-religious practices of Saraguros; ii) to identify the main components of plant hydromethanolic extracts; iiì) to test the effects of alkaloidal fractions on the activity of two enzymes linked to mental health. All the interviewed Saraguro yachak showed a high consensus about the uses of the seven Huperzia plants as purgatives and against supernatural diseases, such as the "espanto" (startle). In admixtures with other plants, some species also induce a state of trance or hallucinations in participants in magical-religious rituals. GC-MS of the volatile alkaloid fractions allowed the identification of some lycodine-type and lycopodine-type alkaloids (1-5) in H. compacta, H. columnaris, and H. tetragona. The flavones selgin) (6) and tricin (7) were isolated from H. brevifolia and H. espinosana. Tricin (7) was also detected in the other five species. The rare serratene triterpenes serratenediol (8) serratenediol-3-O-acetate (9), 21-episerratenediol (10), and 21-episerratenediol-3-O-acetate (11) were isolated from H. crassa. In addition, the presence of an unprecedented group of high molecular weight alkaloids has been determined. Alkaloid fractions

Diffusion of innovations: treatment of Alzheimer's disease in Germany.

PubMed

Ruof, Jörg; Mittendorf, Thomas; Pirk, Olaf; von der Schulenburg, J-Matthias Graf

2002-04-01

Systematic barriers seem to slow down the market penetration of innovative acethylcholinesterase (AChE) inhibitors in Alzheimer's disease. The goal of our study was to examine the diffusion of AChE inhibitors into the German market in more detail. On the basis of using the ongoing surveillance panel of the Institute of Medical Statistic (IMS) Health, the prescription patterns of 100 physicians (72 general practitioners, 28 neurologists) were examined. In addition, structured telephone interviews with the same 100 physicians were conducted. The interview included the assessment of a hypothetical treatment situation (i.e. physicians were asked what they would prescribe if a close relative of theirs had Alzheimer's disease) as well as qualitative items examining the physicians' attitudes towards AChE inhibitors and the perceived impact on drug budgets. As a major result, the analysis revealed that neurologists prescribed AChE inhibitors to 44.6% of their patients, while general practitioners only treated 9.0% of their patients with AChE inhibitors. The analysis of the qualitative items revealed positive attitudes regarding the safety and efficacy of AChE inhibitors, but negative attitudes regarding the budgetary limitations to prescribing these drugs. A correlation of r=0.21 (P<0.05) was found between the perceived impact on drug budgets and the adoption of AChE inhibitors and a correlation of r=0.32 (P<0.002) was seen between the physician's specialty and the adoption of AChE inhibitors. These data show that, while the AChE inhibitor adoption process has passed the early stages, various barriers slow down the final stages of AChE inhibitor adoption. The drug budget in particular seems to inhibit the adoption of the innovation by the majority of general practitioners. This leads to a more short-term cost control strategy instead of long-term disease management and cost saving approaches.

Sympathetic α₃β₂-nAChRs mediate cerebral neurogenic nitrergic vasodilation in the swine.

PubMed

Lee, Reggie Hui-Chao; Liu, Yi-Qing; Chen, Po-Yi; Liu, Chin-Hung; Chen, Mei-Fang; Lin, Hung-Wen; Kuo, Jon-Son; Premkumar, Louis S; Lee, Tony Jer-Fu

2011-08-01

The α(7)-nicotinic ACh receptor (α(7)-nAChR) on sympathetic neurons innervating basilar arteries of pigs crossed bred between Landrace and Yorkshire (LY) is known to mediate nicotine-induced, β-amyloid (Aβ)-sensitive nitrergic neurogenic vasodilation. Preliminary studies, however, demonstrated that nicotine-induced cerebral vasodilation in pigs crossbred among Landrace, Yorkshire, and Duroc (LYD) was insensitive to Aβ and α-bungarotoxin (α-BGTX). We investigated nAChR subtype on sympathetic neurons innervating LYD basilar arteries. Nicotine-induced relaxation of porcine isolated basilar arteries was examined by tissue bath myography, inward currents on nAChR-expressing oocytes by two-electrode voltage recording, and mRNA and protein expression in the superior cervical ganglion (SCG) and middle cervical ganglion (MCG) by reverse transcription PCR and Western blotting. Nicotine-induced basilar arterial relaxation was not affected by Aβ, α-BGTX, and α-conotoxin IMI (α(7)-nAChR antagonists), or α-conotoxin AuIB (α(3)β(4)-nAChR antagonist) but was inhibited by tropinone and tropane (α(3)-containing nAChR antagonists) and α-conotoxin MII (selective α(3)β(2)-nAChR antagonist). Nicotine-induced inward currents in α(3)β(2)-nAChR-expressing oocytes were inhibited by α-conotoxin MII but not by α-BGTX, Aβ, or α-conotoxin AuIB. mRNAs of α(3)-, α(7)-, β(2)-, and β(4)-subunits were expressed in both SCGs and MCGs with significantly higher mRNAs of α(3)-, β(2)-, and β(4)-subunits than that of α(7)-subunit. The Aβ-insensitive sympathetic α(3)β(2)-nAChR mediates nicotine-induced cerebral nitrergic neurogenic vasodilation in LYD pigs. The different finding from Aβ-sensitive α(7)-nAChR in basilar arteries of LY pigs may offer a partial explanation for different sensitivities of individuals to Aβ in causing diminished cerebral nitrergic vasodilation in diseases involving Aβ.

Insect-specific irreversible inhibitors of acetylcholinesterase in pests including the bed bug, the eastern yellowjacket, German and American cockroaches, and the confused flour beetle.

PubMed

Polsinelli, Gregory A; Singh, Sanjay K; Mishra, Rajesh K; Suranyi, Robert; Ragsdale, David W; Pang, Yuan-Ping; Brimijoin, Stephen

2010-09-06

Insecticides directed against acetylcholinesterase (AChE) are facing increased resistance among target species as well as increasing concerns for human toxicity. The result has been a resurgence of disease vectors, insects destructive to agriculture, and residential pests. We previously reported a free cysteine (Cys) residue at the entrance to the AChE active site in some insects but not higher vertebrates. We also reported Cys-targeting methanethiosulfonate molecules (AMTSn), which, under conditions that spared human AChE, caused total irreversible inhibition of aphid AChE, 95% inhibition of AChE from the malaria vector mosquito (Anopheles gambia), and >80% inhibition of activity from the yellow fever mosquito (Aedes aegypti) and northern house mosquito (Culex pipiens). We now find the same compounds inhibit AChE from cockroaches (Blattella germanica and Periplaneta americana), the flour beetle (Tribolium confusum), the multi-colored Asian ladybird beetle (Harmonia axyridis), the bed bug (Cimex lectularius), and a wasp (Vespula maculifrons), with IC(50) values of approximately 1-11muM. Our results support further study of Cys-targeting inhibitors as conceptually novel insecticides that may be free of resistance in a range of insect pests and disease vectors and, compared with current compounds, should demonstrate much lower toxicity to mammals, birds, and fish. Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.

Designing Novel Quaternary Quantum Reversible Subtractor Circuits

NASA Astrophysics Data System (ADS)

Haghparast, Majid; Monfared, Asma Taheri

2018-01-01

Reversible logic synthesis is an important area of current research because of its ability to reduce energy dissipation. In recent years, multiple valued logic has received great attention due to its ability to reduce the width of the reversible circuit which is a main requirement in quantum technology. Subtractor circuits are between major components used in quantum computers. In this paper, we will discuss the design of a quaternary quantum reversible half subtractor circuit using quaternary 1-qudit, 2-qudit Muthukrishnan-Stroud and 3-qudit controlled gates and a 2-qudit Generalized quaternary gate. Then a design of a quaternary quantum reversible full subtractor circuit based on the quaternary half subtractor will be presenting. The designs shall then be evaluated in terms of quantum cost, constant input, garbage output, and hardware complexity. The proposed quaternary quantum reversible circuits are the first attempt in the designing of the aforementioned subtractor.

Design, synthesis, and pharmacological evaluation of a novel series of hormone sensitive lipase inhibitor.

PubMed

Ogiyama, Tomoko; Yamaguchi, Mitsuhiro; Kurikawa, Nobuya; Honzumi, Shoko; Terayama, Koji; Nagaoka, Nobumi; Yamamoto, Yuka; Kimura, Takako; Sugiyama, Daisuke; Inoue, Shin-Ichi

2017-09-01

HSL inhibition is a promising approach to the treatment of dyslipidemia. As a result of re-optimization of lead compound 2, we identified novel compound 25a exhibiting potent inhibitory activity against HSL enzyme and cell with high selectivity for cholinesterases (AChE and BuChE). Reflecting its potent in vitro activity, compound 25a exhibited antilipolytic effect in rats at 1mg/kg p.o., which indicated that this novel compound is the most potent orally active HSL inhibitor. Moreover, compound 25a did not show bioactivation liability. Copyright © 2017 Elsevier Ltd. All rights reserved.

Differential effects of lysophosphatidylcholine and ACh on muscarinic K(+),non-selective cation and Ca(2+) currents in guinea-pig atrial cells.

PubMed

Li, Libing; Matsuoka, Isao; Sakamoto, Kazuho; Kimura, Junko

2016-06-08

We compared the effects of lysophosphatidylcholine (LPC) and acetylcholine (ACh) on IK(ACh), ICa and a non-selective cation current (INSC) in guinea-pig atrial myocytes to clarify whether LPC and ACh activate similar Gi/o-coupled effector systems.　IK(ACh), ICa and INSC were analyzed in single atrial myocytes by the whole cell patch-clamp.　LPC induced INSC in a concentration-dependent manner in atrial cells.　ACh activated IK(ACh), but failed to evoke INSC.　LPC also activated IK(ACh) but with significantly less potency than ACh.　The effects of both ligands on IK(ACh) were inhibited by intracellular loading of pre-activated PTX.　This treatment also inhibited LPC-induced INSC, indicating that IK(ACh) and INSC induced by LPC are both mediated by Gi/o.　LPC and ACh had similar potencies in inhibiting ICa, which was pre-augmented by forskolin, indicating that LPC and ACh activate similar amounts of α-subunits of Gi/o.　The different effects of LPC and ACh on IK(ACh) and INSC may suggest that LPC and ACh activate Gi/o having different types of βγ subunits, and that LPC-induced INSC may be mediated by βγ subunits of Gi/o, which are less effective in inducing IK(ACh).

One-pot microwave assisted stereoselective synthesis of novel dihydro-2'H-spiro[indene-2,1'-pyrrolo-[3,4-c]pyrrole]-tetraones and evaluation of their antimycobacterial activity and inhibition of AChE.

PubMed

Bharkavi, Chelliah; Vivek Kumar, Sundaravel; Ashraf Ali, Mohamed; Osman, Hasnah; Muthusubramanian, Shanmugam; Perumal, Subbu

2017-07-15

An efficient one-pot microwave assisted stereoselective synthesis of novel dihydro-2'H-spiro[indene-2,1'-pyrrolo[3,4-c]pyrrole]-tetraone derivatives through three-component 1,3-dipolar cycloaddition of azomethine ylides generated in situ from ninhydrin and sarcosine with a series of 1-aryl-1H-pyrrole-2,5-diones is described. The synthesised compounds were screened for their antimycobacterial and AChE inhibition activities. Compound 4b (IC 50 1.30µM) has been found to display twelve fold antimycobacterial activity compared to cycloserine and it is thirty seven times more active than pyrimethamine. Compound 4h displays maximum AchE inhibitory activity with IC 50 value of 0.78±0.01µmol/L. Copyright © 2017 Elsevier Ltd. All rights reserved.

Identification and Expression of Acetylcholinesterase in Octopus vulgaris Arm Development and Regeneration: a Conserved Role for ACHE?

PubMed

Fossati, Sara Maria; Candiani, Simona; Nödl, Marie-Therese; Maragliano, Luca; Pennuto, Maria; Domingues, Pedro; Benfenati, Fabio; Pestarino, Mario; Zullo, Letizia

2015-08-01

Acetylcholinesterase (ACHE) is a glycoprotein with a key role in terminating synaptic transmission in cholinergic neurons of both vertebrates and invertebrates. ACHE is also involved in the regulation of cell growth and morphogenesis during embryogenesis and regeneration acting through its non-cholinergic sites. The mollusk Octopus vulgaris provides a powerful model for investigating the mechanisms underlying tissue morphogenesis due to its high regenerative power. Here, we performed a comparative investigation of arm morphogenesis during adult arm regeneration and embryonic arm development which may provide insights on the conserved ACHE pathways. In this study, we cloned and characterized O. vulgaris ACHE, finding a single highly conserved ACHE hydrophobic variant, characterized by prototypical catalytic sites and a putative consensus region for a glycosylphosphatidylinositol (GPI)-anchor attachment at the COOH-terminus. We then show that its expression level is correlated to the stage of morphogenesis in both adult and embryonic arm. In particular, ACHE is localized in typical neuronal sites when adult-like arm morphology is established and in differentiating cell locations during the early stages of arm morphogenesis. This possibility is also supported by the presence in the ACHE sequence and model structure of both cholinergic and non-cholinergic sites. This study provides insights into ACHE conserved roles during processes of arm morphogenesis. In addition, our modeling study offers a solid basis for predicting the interaction of the ACHE domains with pharmacological blockers for in vivo investigations. We therefore suggest ACHE as a target for the regulation of tissue morphogenesis.

H2 formation via the UV photo-processing of a-C:H nano-particles

NASA Astrophysics Data System (ADS)

Jones, A. P.; Habart, E.

2015-09-01

Context. The photolysis of hydrogenated amorphous carbon, a-C(:H), dust by UV photon-irradiation in the laboratory leads to the release of H2 as well as other molecules and radicals. This same process is also likely to be important in the interstellar medium. Aims: We investigate molecule formation arising from the photo-dissociatively-driven, regenerative processing of a-C(:H) dust. Methods: We explore the mechanism of a-C(:H) grain photolysis leading to the formation of H2 and other molecules/radicals. Results: The rate constant for the photon-driven formation of H2 from a-C(:H) grains is estimated to be 2 × 10-17 cm3 s-1. In intense radiation fields photon-driven grain decomposition will lead to fragmentation into daughter species rather than H2 formation. Conclusions: The cyclic re-structuring of arophatic a-C(:H) nano-particles appears to be a viable route to formation of H2 for low to moderate radiation field intensities (1 ≲ G0 ≲ 102), even when the dust is warm (T ~ 50-100 K).

Multitarget drug design strategy against Alzheimer's disease: Homoisoflavonoid Mannich base derivatives serve as acetylcholinesterase and monoamine oxidase B dual inhibitors with multifunctional properties.

PubMed

Li, Yan; Qiang, Xiaoming; Luo, Li; Yang, Xia; Xiao, Ganyuan; Zheng, Yunxiaozhu; Cao, Zhongcheng; Sang, Zhipei; Su, Fu; Deng, Yong

2017-01-15

A series of homoisoflavonoid Mannich base derivatives were designed, synthesized and evaluated as multifunctional agents against Alzheimer's disease. It demonstrated that most of the derivatives were selective AChE and MAO-B dual inhibitors with good multifunctional properties. Among them, compound 10d displayed the comprehensive advantages, with excellent AChE and MAO-B inhibitory activities (IC 50 =2.49±0.08nM and 1.74±0.0581μM, respectively), good self- and Cu 2+ -induced Aβ 1-42 aggregation inhibitory potency, antioxidant activity, biometal chelating ability and high BBB permeability. These multifunctional properties make 10d as an excellent candidate for the development of efficient drugs against AD. Copyright © 2016 Elsevier Ltd. All rights reserved.

In silico development of new acetylcholinesterase inhibitors.

PubMed

Pascoini, A L; Federico, L B; Arêas, A L F; Verde, B A; Freitas, P G; Camps, I

2018-04-19

In this work, we made use of fragment-based drug design (FBDD) and de novo design to obtain more powerful acetylcholinesterase (AChE) inhibitors. AChE is associated with Alzheimer's disease (AD). It was found that the cholinergic pathways in the cerebral cortex are compromised in AD and the accompanying cholinergic deficiency contributes to the cognitive deterioration of AD patients. In the FBDD approach, fragments are docked into the active site of the protein. As fragments are molecular groups with a low number of atoms, it is possible to study their interaction with localized amino acids. Once the interactions are measured, the fragments are organized by affinity and then linked together to form new molecules with a high degree of interaction with the active site. In the other approach, we used the de novo design technique starting from reference drugs used in the AD treatment. These drugs were broken into fragments (seeds). In the growing strategy, fragments were added to each seed, growing new molecules. In the linking strategy, two or more separated seeds were linked with different fragments. Both strategies combined produced a library of more than 2 million compounds. This library was filtered using absorption, distribution, metabolism, and excretion properties. The resulting library with around six thousand compounds was filtered again. In this case, structures with Tanimoto coefficients >.85 were discarded. The final library with 1500 compounds was submitted to docking studies. As a result, 10 compounds with better interaction energy than the reference drugs were obtained.

Functional Human α7 Nicotinic Acetylcholine Receptor (nAChR) Generated from Escherichia coli.

PubMed

Tillman, Tommy S; Alvarez, Frances J D; Reinert, Nathan J; Liu, Chuang; Wang, Dawei; Xu, Yan; Xiao, Kunhong; Zhang, Peijun; Tang, Pei

2016-08-26

Human Cys-loop receptors are important therapeutic targets. High-resolution structures are essential for rational drug design, but only a few are available due to difficulties in obtaining sufficient quantities of protein suitable for structural studies. Although expression of proteins in E. coli offers advantages of high yield, low cost, and fast turnover, this approach has not been thoroughly explored for full-length human Cys-loop receptors because of the conventional wisdom that E. coli lacks the specific chaperones and post-translational modifications potentially required for expression of human Cys-loop receptors. Here we report the successful production of full-length wild type human α7nAChR from E. coli Chemically induced chaperones promote high expression levels of well-folded proteins. The choice of detergents, lipids, and ligands during purification determines the final protein quality. The purified α7nAChR not only forms pentamers as imaged by negative-stain electron microscopy, but also retains pharmacological characteristics of native α7nAChR, including binding to bungarotoxin and positive allosteric modulators specific to α7nAChR. Moreover, the purified α7nAChR injected into Xenopus oocytes can be activated by acetylcholine, choline, and nicotine, inhibited by the channel blockers QX-222 and phencyclidine, and potentiated by the α7nAChR specific modulators PNU-120596 and TQS. The successful generation of functional human α7nAChR from E. coli opens a new avenue for producing mammalian Cys-loop receptors to facilitate structure-based rational drug design. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Effects of Anticholinesterases on Catalysis and Induced Conformational Change of the Peripheral Anionic Site of Murine Acetylcholinesterase

PubMed Central

Tong, Fan; Islam, Rafique M.; Carlier, Paul R.; Ma, Ming; Ekström, Fredrik; Bloomquist, Jeffrey R.

2013-01-01

Conventional insecticides targeting acetylcholinesterase (AChE) typically show high mammalian toxicities and because there is resistance to these compounds in many insect species, alternatives to established AChE inhibitors used for pest control are needed. Here we used a fluorescence method to monitor interactions between various AChE inhibitors and the AChE peripheral anionic site, which is a novel target for new insecticides acting on this enzyme. The assay uses thioflavin-T as a probe, which binds to the peripheral anionic site of AChE and yields an increase in fluorescent signal. Three types of AChE inhibitors were studied: catalytic site inhibitors (carbamate insecticides, edrophonium, and benzylpiperidine), peripheral site inhibitors (tubocurarine, ethidium bromide, and propidium iodide), and bivalent inhibitors (donepezil, BW284C51, and a series of bis(n)-tacrines). All were screened on murine AChE to compare and contrast changes of peripheral site conformation in the TFT assay with catalytic inhibition. All the inhibitors reduced thioflavin-T fluorescence in a concentration-dependent manner with potencies (IC50) ranging from 8 nM for bis(6)-tacrine to 159 μM for benzylpiperidine. Potencies in the fluorescence assay were correlated well with their potencies for enzyme inhibition (R2 = 0.884). Efficacies for reducing thioflavin-T fluorescence ranged from 23–36% for catalytic site inhibitors and tubocurarine to near 100% for ethidium bromide and propidium iodide. Maximal efficacies could be reconciled with known mechanisms of interaction of the inhibitors with AChE. When extended to pest species, we anticipate these findings will assist in the discovery and development of novel, selective bivalent insecticides acting on AChE. PMID:24003261

Synthesis, spectroscopic, computational (DFT/B3LYP), AChE inhibition and antioxidant studies of imidazole derivative

NASA Astrophysics Data System (ADS)

Ahmad, Faheem; Alam, Mohammad Jane; Alam, Mahboob; Azaz, Shaista; Parveen, Mehtab; Park, Soonheum; Ahmad, Shabbir

2018-01-01

The present study reports the synthesis and evaluation of biological properties of 3a,8a-dihydroxy-8-oxo-1,3,3a,8a-tetrahydroindeno[1,2-d]imidazol-2(1H)-iminium chloride (3). The structure was confirmed by the FTIR, NMR, MS, CHN microanalysis and X-ray crystallographic analysis. Quantum chemical calculations have been performed at B3LYP-D3/6-311++G(d,p) level of theory to study the molecular geometry, IR, (1H and 13C) NMR, UV/Vis spectra and other molecular parameters of the asymmetric unit of crystal of imidazole compound (3). An empirical dispersion correction to hybrid functional (B3LYP-D3) has been incorporated in the present calculations due to presence of non-covalent interaction, Cl⋯H-O, in the present compound. The remarkable agreement has been observed between theoretical data and those measured experimentally. Moreover, the Hirshfeld analysis was carried out to ascertain the secondary interactions and associated 2D fingerprint plots. The synthesized imidazole derivative showed promising antioxidant property and inhibitory activity against acetylcholinesterase (AChE). Molecular docking was also performed in order to explain in silico antioxidant studies and to ascertain the probable binding mode of compound with the amino acid residues of protein.

α5 nAChR modulation of the prefrontal cortex makes attention resilient.

PubMed

Howe, William M; Brooks, Julie L; Tierney, Patrick L; Pang, Jincheng; Rossi, Amie; Young, Damon; Dlugolenski, Keith; Guillmette, Ed; Roy, Marc; Hales, Katherine; Kozak, Rouba

2018-03-01

A loss-of-function polymorphism in the α5 nicotinic acetylcholine receptor (nAChR) subunit gene has been linked to both drug abuse and schizophrenia. The α5 nAChR subunit is strategically positioned in the prefrontal cortex (PFC), where a loss-of-function in this subunit may contribute to cognitive disruptions in both disorders. However, the specific contribution of α5 to PFC-dependent cognitive functions has yet to be illustrated. In the present studies, we used RNA interference to knockdown the α5 nAChR subunit in the PFC of adult rats. We provide evidence that through its contribution to cholinergic modulation of cholinergic modulation of neurons in the PFC, the α5 nAChR plays a specific role in the recovery of attention task performance following distraction. Our combined data reveal the potent ability of this subunit to modulate the PFC and cognitive functions controlled by this brain region that are impaired in disease.

The Citicholinage Study: Citicoline Plus Cholinesterase Inhibitors in Aged Patients Affected with Alzheimer's Disease Study.

PubMed

Gareri, Pietro; Castagna, Alberto; Cotroneo, Antonino Maria; Putignano, Daria; Conforti, Raffaele; Santamaria, Francesco; Marino, Saverio; Putignano, Salvatore

2017-01-01

Citicoline can have beneficial effects both in degenerative and in vascular cognitive decline in a variety of ways (apoptosis inhibition, neuroplasticity potentiation, phospholipid, and acetylcholine (ACh) synthesis). Acetylcholinesterase inhibitors (AChEIs) have been used for treatment of Alzheimer's disease (AD). When co-administered with cholinergic precursors, they are able to increase the intrasynaptic levels of ACh more than when the single drugs given alone. The aim of the present study was to show the effectiveness of oral citicoline plus AChEIs in patients affected with AD. This was a retrospective multi-centric case-control study, involving seven Centers for Cognitive Impairment and Dementia in Italy, on 448 consecutive patients aged 65 years old or older affected with AD. 197 patients were treated with an AChEI while 251 were treated with an AchEI + citicoline 1000 mg/day given orally. Cognitive functions were assessed by MMSE, daily life functions by ADL and IADL, behavioral symptoms by NPI, comorbidities by CIRS, and mood by GDS-short form. Tests were administered at baseline (T0), after 3 (T1), and 9 months (T2). The primary outcomes were effects of combined administration versus AChEIs given alone on cognitive functions assessed by MMSE. The secondary outcomes were possible side effects or adverse events of combination therapy versus AChEIs alone. Patients treated with citicoline plus an AChEI showed a statistically significant increase in MMSE between T0 and T1 (16.88±3.38 versus 17.62±3.64; p = 0.000) and between T1 and T2 (17.62±3.64 versus 17.89±3.54; p = 0.000). The present study encourages the role of combined administration in disease management by slowing disease progression.

Copper (II) and zinc (II) complexes with flavanone derivatives: Identification of potential cholinesterase inhibitors by on-flow assays.

PubMed

Sarria, André Lucio Franceschini; Vilela, Adriana Ferreira Lopes; Frugeri, Bárbara Mammana; Fernandes, João Batista; Carlos, Rose Maria; da Silva, Maria Fátima das Graças Fernandes; Cass, Quezia Bezerra; Cardoso, Carmen Lúcia

2016-11-01

Metal chelates strongly influence the nature and magnitude of pharmacological activities in flavonoids. In recent years, studies have shown that a promising class of flavanone-metal ion complexes can act as selective cholinesterase inhibitors (ChEIs), which has led our group to synthesize a new series of flavanone derivatives (hesperidin, hesperetin, naringin, and naringenin) complexed to either copper (II) or zinc (II) and to evaluate their potential use as selective ChEIs. Most of the synthesized complexes exhibited greater inhibitory activity against acetylcholinesterase (AChE) than against butyrylcholinesterase (BChE). Nine of these complexes constituted potent, reversible, and selective ChEIs with inhibitory potency (IC 50 ) and inhibitory constant (K i ) ranging from 0.02 to 4.5μM. Copper complexes with flavanone-bipyridine derivatives afforded the best inhibitory activity against AChE and BChE. The complex Cu(naringin)(2,2'-bipyridine) (11) gave IC 50 and K i values of 0.012±0.002 and 0.07±0.01μM for huAChE, respectively, which were lower than the inhibitory values obtained for standard galanthamine (IC 50 =206±30.0 and K i =126±18.0μM). Evaluation of the inhibitory activity of this complex against butyrylcholinesterase from human serum (huBChE) gave IC 50 and K i values of 8.0±1.4 and 2.0±0.1μM, respectively. A Liquid Chromatography-Immobilized Capillary Enzyme Reactor by UV detection (LC-ICER-UV) assay allowed us to determine the IC 50 and K i values and the type of mechanism for the best inhibitors. Copyright © 2016 Elsevier Inc. All rights reserved.

Synthesis and biological evaluation of a new series of ebselen derivatives as glutathione peroxidase (GPx) mimics and cholinesterase inhibitors against Alzheimer's disease.

PubMed

Luo, Zonghua; Liang, Liang; Sheng, Jianfei; Pang, Yanqing; Li, Jianheng; Huang, Ling; Li, Xingshu

2014-02-15

A series of ebselen derivatives were designed, synthesised and evaluated as inhibitors of cholinesterases (ChEs) and glutathione peroxidase (GPx) mimics. Most of the compounds were found to be potent against AChEs and BuChE, compounds 5e and 5i, proved to be the most potent against AChE with IC₅₀ values of 0.76 and 0.46 μM, respectively. Among these hybrids, most of the compounds were found to be good GPx mimics compare with ebselen. The selected compounds 5e and 5i were also used to determine the catalytic parameters and in vitro hydrogen peroxide scavenging activity. The results indicate that compounds 5e and 5i may be excellent multifunctional agents for the treatment of AD. Copyright © 2014 Elsevier Ltd. All rights reserved.

Partitioning the Quaternary

NASA Astrophysics Data System (ADS)

Gibbard, Philip L.; Lewin, John

2016-11-01

We review the historical purposes and procedures for stratigraphical division and naming within the Quaternary, and summarize the current requirements for formal partitioning through the International Commission on Stratigraphy (ICS). A raft of new data and evidence has impacted traditional approaches: quasi-continuous records from ocean sediments and ice cores, new numerical dating techniques, and alternative macro-models, such as those provided through Sequence Stratigraphy and Earth-System Science. The practical usefulness of division remains, but there is now greater appreciation of complex Quaternary detail and the modelling of time continua, the latter also extending into the future. There are problems both of commission (what is done, but could be done better) and of omission (what gets left out) in partitioning the Quaternary. These include the challenge set by the use of unconformities as stage boundaries, how to deal with multiphase records in ocean and terrestrial sediments, what happened at the 'Early-Mid- (Middle) Pleistocene Transition', dealing with trends that cross phase boundaries, and the current controversial focus on how to subdivide the Holocene and formally define an 'Anthropocene'.

Single channel properties of human α3 AChRs: impact of β2, β4 and α5 subunits

PubMed Central

Nelson, Mark E; Lindstrom, Jon

1999-01-01

We performed single channel analysis on human α3 acetylcholine receptors (AChRs) in Xenopus oocytes and native AChRs from the human neuroblastoma cell line IMR-32. α3 AChRs exhibit channel properties that reflect subunit composition.α3β2 AChR open times were 0.71 ± 0.14 and 3.5 ± 0.4 ms with a predominant conductance of 26 pS. α3β4 AChRs had open times of 1.4 ± 0.2 and 6.5 ± 0.8 ms and a predominant conductance of 31 pS. Burst times were 0.82 ± 0.12 and 5.3 ± 0.7 ms for α3β2 and 1.7 ± 0.1 and 16 ± 1 ms for α3β4. Desensitization was faster for AChRs with the β2 subunit than for those with the β4 subunit.One open time for α3α5β2 AChRs (5.5 ± 0.3 ms) was different from those of α3β2 AChRs. For α3α5β4 AChRs, an additional conductance, open time and burst time (36 pS, 22 ± 3 ms and 43 ± 4 ms, respectively) were different from those for α3β4 AChRs.α3 AChRs were inhibited by hexamethonium or mecamylamine. The rate constants for block of α3β4 by hexamethonium and of α3β2 by mecamylamine were 1.2 × 107 and 4.6 × 107 M−1 s−1, respectively.AChRs from IMR-32 cells had a predominant conductance of 32 pS and open times of 1.5 ± 0.3 and 9.6 ± 1.2 ms. These properties were most similar to those of α3β4 AChRs expressed in oocytes. Antibodies revealed that 5 ± 2% of IMR-32 α3 AChRs contained α5 subunits and 6 ± 2% contained β2 subunits. IMR-32 α3 AChRs are primarily α3β4 AChRs. PMID:10200416

Muscle-specific kinase (MuSK) autoantibodies suppress the MuSK pathway and ACh receptor retention at the mouse neuromuscular junction

PubMed Central

Ghazanfari, Nazanin; Morsch, Marco; Reddel, Stephen W; Liang, Simon X; Phillips, William D

2014-01-01

Muscle-specific kinase (MuSK) autoantibodies from myasthenia gravis patients can block the activation of MuSK in vitro and/or reduce the postsynaptic localization of MuSK. Here we use a mouse model to examine the effects of MuSK autoantibodies upon some key components of the postsynaptic MuSK pathway and upon the regulation of junctional ACh receptor (AChR) numbers. Mice became weak after 14 daily injections of anti-MuSK-positive patient IgG. The intensity and area of AChR staining at the motor endplate was markedly reduced. Pulse-labelling of AChRs revealed an accelerated loss of pre-existing AChRs from postsynaptic AChR clusters without a compensatory increase in incorporation of (newly synthesized) replacement AChRs. Large, postsynaptic AChR clusters were replaced by a constellation of tiny AChR microaggregates. Puncta of AChR staining also appeared in the cytoplasm beneath the endplate. Endplate staining for MuSK, activated Src, rapsyn and AChR were all reduced in intensity. In the tibialis anterior muscle there was also evidence that phosphorylation of the AChR β-subunit-Y390 was reduced at endplates. In contrast, endplate staining for β-dystroglycan (through which rapsyn couples AChR to the synaptic basement membrane) remained intense. The results suggest that anti-MuSK IgG suppresses the endplate density of MuSK, thereby down-regulating MuSK signalling activity and the retention of junctional AChRs locally within the postsynaptic membrane scaffold. PMID:24860174

Muscle-specific kinase (MuSK) autoantibodies suppress the MuSK pathway and ACh receptor retention at the mouse neuromuscular junction.

PubMed

Ghazanfari, Nazanin; Morsch, Marco; Reddel, Stephen W; Liang, Simon X; Phillips, William D

2014-07-01

Muscle-specific kinase (MuSK) autoantibodies from myasthenia gravis patients can block the activation of MuSK in vitro and/or reduce the postsynaptic localization of MuSK. Here we use a mouse model to examine the effects of MuSK autoantibodies upon some key components of the postsynaptic MuSK pathway and upon the regulation of junctional ACh receptor (AChR) numbers. Mice became weak after 14 daily injections of anti-MuSK-positive patient IgG. The intensity and area of AChR staining at the motor endplate was markedly reduced. Pulse-labelling of AChRs revealed an accelerated loss of pre-existing AChRs from postsynaptic AChR clusters without a compensatory increase in incorporation of (newly synthesized) replacement AChRs. Large, postsynaptic AChR clusters were replaced by a constellation of tiny AChR microaggregates. Puncta of AChR staining also appeared in the cytoplasm beneath the endplate. Endplate staining for MuSK, activated Src, rapsyn and AChR were all reduced in intensity. In the tibialis anterior muscle there was also evidence that phosphorylation of the AChR β-subunit-Y390 was reduced at endplates. In contrast, endplate staining for β-dystroglycan (through which rapsyn couples AChR to the synaptic basement membrane) remained intense. The results suggest that anti-MuSK IgG suppresses the endplate density of MuSK, thereby down-regulating MuSK signalling activity and the retention of junctional AChRs locally within the postsynaptic membrane scaffold. © 2014 The Authors. The Journal of Physiology © 2014 The Physiological Society.

Cholinesterase enzymes inhibitors from the leaves of Rauvolfia reflexa and their molecular docking study.

PubMed

Fadaeinasab, Mehran; Hadi, A Hamid A; Kia, Yalda; Basiri, Alireza; Murugaiyah, Vikneswaran

2013-03-25

Plants of the Apocynaceae family have been traditionally used in the treatment of age-related brain disorders. Rauvolfia reflexa, a member of the family, has been used as an antidote for poisons and to treat malaria. The dichloromethane, ethanol and methanol extracts from the leaves of Rauvolfia reflexa showed potential acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities, with IC50 values in the 8.49 to 52.23 g/mL range. Further cholinesterase inhibitory-guided isolation of these extracts afforded four bioactive compounds, namely: (E)-3-(3,4,5-trimethoxyphenyl)acrylic acid (1), (E)-methyl 3-(4-hydroxy-3,5-dimethoxyphenyl) acrylate (2), 17-methoxycarbonyl-14-heptadecaenyl-4-hydroxy-3-methoxycinnamate (3) and 1,2,3,4-tetrahydro-1-oxo-β-carboline (4). The isolated compounds showed moderate cholinesterase inhibitory activity compared to the reference standard, physostigmine. Compounds 1 and 2 showed the highest inhibitory activity against AChE (IC50 = 60.17 µM) and BChE (IC50 = 61.72 µM), respectively. Despite having similar molecular weight, compounds 1 and 2 were structurally different according to their chemical substitution patterns, leading to their different enzyme inhibition selectivity. Compound 2 was more selective against BChE, whereas compound 1 was a selective inhibitor of AChE. Molecular docking revealed that both compounds 1 and 2 were inserted, but not deeply into the active site of the cholinesterase enzymes.

Efficacy of acetylcholinesterase inhibitors versus nootropics in Alzheimer's disease: a retrospective, longitudinal study.

PubMed

Tsolaki, M; Pantazi, T; Kazis, A

2001-01-01

The aim of this study was to investigate the efficacy of nootropics (piracetam, aniracetam, nimodopine and dihydroergicristine) versus acetylcholinesterase inhibitors (AChE-Is) (tacrine and donepezil) in the treatment of Alzheimer's disease. This is a retrospective study of 510 patients with Alzheimer's disease. To determine clinical efficacy of treatment, we used the mean change over time in scores for the following tests: the Mini-Mental State Examination (MMSE); the Cambridge Cognitive Examination for the Elderly; and the Functional Rating Scale for Symptoms of Dementia. In all patients and in patients with severe Alzheimer's disease (baseline MMSE < 11), no significant differences were seen in the neuropsychological test scores between the two treatment groups. In patients with moderate dementia (baseline MMSE between 11 and 20), however, there was a significantly greater deterioration, as shown on the CAMCOG scale, after 12 months' treatment for patients receiving AChE-Is compared with those receiving nootropics (-4.38 for AChE-Is group versus 1.48 for nootropics group). For patients with mild dementia (baseline MMSE score between 21 and 26), there was a significantly greater deterioration on the MMSE scale for each time-point in the nootropics group compared with the AChE-Is group. In conclusion, we did not find any strong evidence that a difference in efficacy exists between AChE-Is and nootropics in the treatment of Alzheimer's disease.

The role of the peripheral anionic site and cation-pi interactions in the ligand penetration of the human AChE gorge.

PubMed

Branduardi, Davide; Gervasio, Francesco Luigi; Cavalli, Andrea; Recanatini, Maurizio; Parrinello, Michele

2005-06-29

We study the ligand (tetramethylammonium) recognition by the peripheral anionic site and its penetration of the human AChE gorge by using atomistic molecular dynamics simulations and our recently developed metadynamics method. The role of both the peripheral anionic site and the formation of cation-pi interactions in the ligand entrance are clearly shown. In particular, a simulation with the W286A mutant shows the fundamental role of this residue in anchoring the ligand at the peripheral anionic site of the enzyme and in positioning it prior to the gorge entrance. Once the ligand is properly oriented, the formation of specific and synchronized cation-pi interactions with W86, F295, and Y341 enables the gorge penetration. Eventually, the ligand is stabilized in a free energy basin by means of cation-pi interactions with W86.

Pterostilbene-O-acetamidoalkylbenzylamines derivatives as novel dual inhibitors of cholinesterase with anti-β-amyloid aggregation and antioxidant properties for the treatment of Alzheimer's disease.

PubMed

Li, Yuxing; Qiang, Xiaoming; Li, Yan; Yang, Xia; Luo, Li; Xiao, Ganyuan; Cao, Zhongcheng; Tan, Zhenghuai; Deng, Yong

2016-04-15

A series of pterostilbene-O-acetamidoalkylbenzylamines were designed, synthesized and evaluated as dual inhibitors of AChE and BuChE. To further explore the multifunctional properties of the new derivatives, their antioxidant activities and inhibitory effects on self-induced Aβ1-42 aggregation and HuAChE-induced Aβ1-40 aggregation were also tested. The results showed that most of these compounds could effectively inhibit AChE and BuChE. Particularly, compound 21d exhibited the best AChE inhibitory activity (IC50=0.06 μM) and good inhibition of BuChE (IC50=28.04 μM). Both the inhibition kinetic analysis and molecular modeling study revealed that these compounds showed mixed-type inhibition, binding simultaneously to the CAS and PAS of AChE. In addition to cholinesterase inhibitory activities, these compounds showed different levels of antioxidant activity. However, the inhibitory activities against self-induced and HuAChE-induced Aβ aggregation of these new derivatives were unsatisfied. Taking into account the results of the biological evaluation, further modifications will be designed in order to increase the potency on the different targets. The results displayed in this Letter can be a new starting point for further development of multifunctional agents for Alzheimer's disease. Copyright © 2016 Elsevier Ltd. All rights reserved.

9-Substituted acridine derivatives as acetylcholinesterase and butyrylcholinesterase inhibitors possessing antioxidant activity for Alzheimer's disease treatment.

PubMed

Makhaeva, Galina F; Lushchekina, Sofya V; Boltneva, Natalia P; Serebryakova, Olga G; Rudakova, Elena V; Ustyugov, Alexey A; Bachurin, Sergey O; Shchepochkin, Alexander V; Chupakhin, Oleg N; Charushin, Valery N; Richardson, Rudy J

2017-11-01

We investigated the inhibitory activity of 4 groups of novel acridine derivatives against acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and carboxylesterase (CaE) using the methods of enzyme kinetics and molecular docking. Antioxidant activity of the compounds was determined using the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS + ) radical decolorization assay as their ability to scavenge free radicals. Analysis of the esterase profiles and antiradical activities of the acridine derivatives showed that 9-aryl(heteroaryl)-N-methyl-9,10-dihydroacridines have a high radical-scavenging activity but low potency as AChE and BChE inhibitors, whereas 9-aryl(heteroaryl)-N-methyl-acridinium tetrafluoroborates effectively inhibit cholinesterases but do not exhibit antiradical activity. In contrast, a group of derivatives of 9-heterocyclic amino-N-methyl-9,10-dihydroacridine has been found that combine effective inhibition of AChE and BChE with rather high radical-scavenging activity. The results of molecular docking well explain the observed features in the efficacy, selectivity, and mechanism of cholinesterase inhibition by the acridine derivatives. Thus, in a series of acridine derivatives we have found compounds possessing dual properties of effective and selective cholinesterase inhibition together with free radical scavenging, which makes promising the use of the acridine scaffold to create multifunctional drugs for the therapy of neurodegenerative diseases. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hydroxybenzoic Acid Derivatives as Dual-Target Ligands: Mitochondriotropic Antioxidants and Cholinesterase Inhibitors.

PubMed

Oliveira, Catarina; Cagide, Fernando; Teixeira, José; Amorim, Ricardo; Sequeira, Lisa; Mesiti, Francesco; Silva, Tiago; Garrido, Jorge; Remião, Fernando; Vilar, Santiago; Uriarte, Eugenio; Oliveira, Paulo J; Borges, Fernanda

2018-01-01

Alzheimer's disease (AD) is a multifactorial age-related disease associated with oxidative stress (OS) and impaired cholinergic transmission. Accordingly, targeting mitochondrial OS and restoring cholinergic transmission can be an effective therapeutic strategy toward AD. Herein, we report for the first time dual-target hydroxybenzoic acid (HBAc) derivatives acting as mitochondriotropic antioxidants and cholinesterase (ChE) inhibitors. The studies were performed with two mitochondriotropic antioxidants AntiOxBEN 1 (catechol derivative), and AntiOxBEN 2 (pyrogallol derivative) and compounds 15-18 , which have longer spacers. Compounds AntiOxBEN 1 and 15 , with a shorter carbon chain spacer (six- and eight-carbon) were shown to be potent antioxidants and BChE inhibitors (IC 50 = 85 ± 5 and 106 ± 5 nM, respectively), while compounds 17 and 18 with a 10-carbon chain were more effective AChE inhibitors (IC 50 = 7.7 ± 0.4 and 7.2 ± 0.5 μM, respectively). Interestingly, molecular modeling data pointed toward bifunctional ChEs inhibitors. The most promising ChE inhibitors acted by a non-competitive mechanism. In general, with exception of compounds 15 and 17 , no cytotoxic effects were observed in differentiated human neuroblastoma (SH-SY5Y) and human hepatocarcinoma (HepG2) cells, while Aβ-induced cytotoxicity was significantly prevented by the new dual-target HBAc derivatives. Overall, due to its BChE selectivity, favorable toxicological profile, neuroprotective activity and drug-like properties, which suggested blood-brain barrier (BBB) permeability, the mitochondriotropic antioxidant AntiOxBEN 1 is considered a valid lead candidate for the development of dual acting drugs for AD and other mitochondrial OS-related diseases.

Hydroxybenzoic Acid Derivatives as Dual-Target Ligands: Mitochondriotropic Antioxidants and Cholinesterase Inhibitors

PubMed Central

Oliveira, Catarina; Cagide, Fernando; Teixeira, José; Amorim, Ricardo; Sequeira, Lisa; Mesiti, Francesco; Silva, Tiago; Garrido, Jorge; Remião, Fernando; Vilar, Santiago; Uriarte, Eugenio; Oliveira, Paulo J.; Borges, Fernanda

2018-01-01

Alzheimer's disease (AD) is a multifactorial age-related disease associated with oxidative stress (OS) and impaired cholinergic transmission. Accordingly, targeting mitochondrial OS and restoring cholinergic transmission can be an effective therapeutic strategy toward AD. Herein, we report for the first time dual-target hydroxybenzoic acid (HBAc) derivatives acting as mitochondriotropic antioxidants and cholinesterase (ChE) inhibitors. The studies were performed with two mitochondriotropic antioxidants AntiOxBEN1 (catechol derivative), and AntiOxBEN2 (pyrogallol derivative) and compounds 15–18, which have longer spacers. Compounds AntiOxBEN1 and 15, with a shorter carbon chain spacer (six- and eight-carbon) were shown to be potent antioxidants and BChE inhibitors (IC50 = 85 ± 5 and 106 ± 5 nM, respectively), while compounds 17 and 18 with a 10-carbon chain were more effective AChE inhibitors (IC50 = 7.7 ± 0.4 and 7.2 ± 0.5 μM, respectively). Interestingly, molecular modeling data pointed toward bifunctional ChEs inhibitors. The most promising ChE inhibitors acted by a non-competitive mechanism. In general, with exception of compounds 15 and 17, no cytotoxic effects were observed in differentiated human neuroblastoma (SH-SY5Y) and human hepatocarcinoma (HepG2) cells, while Aβ-induced cytotoxicity was significantly prevented by the new dual-target HBAc derivatives. Overall, due to its BChE selectivity, favorable toxicological profile, neuroprotective activity and drug-like properties, which suggested blood-brain barrier (BBB) permeability, the mitochondriotropic antioxidant AntiOxBEN1 is considered a valid lead candidate for the development of dual acting drugs for AD and other mitochondrial OS-related diseases. PMID:29740575

Hydroxybenzoic acid derivatives as dual-target ligands: mitochondriotropic antioxidants and cholinesterase inhibitors

NASA Astrophysics Data System (ADS)

Oliveira, Catarina; Cagide, Fernando; Teixeira, José; Amorim, Ricardo; Sequeira, Lisa; Mesiti, Francesco; Silva, Tiago; Garrido, Jorge; Remião, Fernando; Vilar, Santiago; Uriarte, Eugenio; Oliveira, Paulo J.; Borges, Fernanda

2018-04-01

Alzheimer’s disease (AD) is a multifactorial age-related disease associated with oxidative stress (OS) and impaired cholinergic transmission. Accordingly, targeting mitochondrial OS and restoring cholinergic transmission can be an effective therapeutic strategy towards AD. Herein, we report for the first time dual-target hydroxybenzoic acid (HBAc) derivatives acting as mitochondriotropic antioxidants and cholinesterase (ChE) inhibitors. The studies were performed with two mitochondriotropic antioxidants AntiOxBEN1 (catechol derivative), and AntiOxBEN2 (pyrogallol derivative) and compounds 15-18, which have longer spacers. Compounds AntiOxBEN1 and 15, with a shorter carbon chain spacer (six- and eight-carbon) were shown to be potent antioxidants and BChE inhibitors (IC50 = 85 ± 5 and 106 ± 5 nM, respectively), while compounds 17 and 18 with a ten-carbon chain were more effective AChE inhibitors (IC50 = 7.7 ± 0.4 and 7.2 ± 0.5 nM, respectively). Interestingly, molecular modelling data pointed towards bifunctional ChEs inhibitors. The most promising ChE inhibitors acted by a non-competitive mechanism. In general, with exception of compounds 15 and 17, no cytotoxic effects were observed in differentiated human neuroblastoma (SH-SY5Y) and human hepatocarcinoma (HepG2) cells, while Αβ-induced cytotoxicity was significantly prevented by the new dual-target HBAc derivatives. Overall, due to its BChE selectivity, favourable toxicological profile, neuroprotective activity and drug-like properties, which suggested blood-brain barrier (BBB) permeability, the mitochondriotropic antioxidant AntiOxBEN1 is considered a valid lead candidate for the development of dual acting drugs for AD and other mitochondrial OS-related disease

Qualitative and quantitative two-dimensional thin-layer chromatography/high performance liquid chromatography/diode-array/electrospray-ionization-time-of-flight mass spectrometry of cholinesterase inhibitors.

PubMed

Mroczek, Tomasz

2016-09-10

Recently launched thin-layer chromatography-mass spectrometry (TLC-MS) interface enabling extraction of compounds directly from TLC plates into MS ion source was unusually extended into two-dimensional thin-layer chromatography/high performance liquid chromatography (2D, TLC/HPLC) system by its a direct connection to a rapid resolution 50×2.1mm, I.D. C18 column compartment followed by detection by diode array (DAD) and electrospray ionisation time-of-flight mass spectrometry (ESI-TOF-MS). In this way, even not separated bands of complicated mixtures of natural compounds could be analysed structurally, only within 1-2min after development of TLC plates. In comparison to typically applied TLC-MS interface, no ion suppression for acidic mobile phases was observed. Also, substantial increase in ESI-TOF-MS sensitivities and quality of spectra, were noticed. It has been utilised in combination with TLC- based bioautographic approaches of acetylcholinesterase (AChE) inhibitors, However, it can be also applied in any other procedures related to bioactivity (e.g. 2,2-Diphenyl-1-picryl-hydrazyl-DPPH screen test for radicals). This system has been also used for determination of half maximal inhibitory concentration (IC50 values) of the active inhibitor-galanthamine, as an example. Moreover, AChE inhibitory potencies of some of purified plant extracts, never studied before, have been quantitatively measured. This is first report of usage such the 2D TLC/HPLC/MS system both for qualitative and quantitative evaluation of cholinesterase inhibitors in biological matrices. Copyright © 2016 Elsevier B.V. All rights reserved.

Novel approaches to study the involvement of α7-nAChR in human diseases.

PubMed

Palma, Eleonora; Conti, Luca; Roseti, Cristina; Limatola, Cristina

2012-05-01

The alpha7 nicotinic acetylcholine receptor (α7 nAChR) is widely distributed in the human brain and has been implicated in a number of human central nervous system (CNS) diseases, including Alzheimer's and Parkinson's disease, schizophrenia and autism. Recently, new roles for α7 nAChRs in lung cancer and heart disease have been elucidated. Despite the importance of this receptor in human pathology, many technical difficulties are still encountered when investigating the role of α7 nAChRs. Electrophysiological analysis of the receptor upon heterologous expression or in human tissues was limited by the fast desensitization of α7-mediated nicotinic currents and by tissue availability. In addition, animal models for the human diseases related to α7 nAChRs have long been unavailable. The recent development of new imaging and analysis approaches such as PET and receptor microtransplantation have rendered the study of α7 nAChRs increasingly feasible, paving new roads to the design of therapeutic drugs. This review summarizes the current knowledge and recent findings obtained by these novel approaches.

Tyrosine kinase inhibitor NVP-BGJ398 functionally improves FGFR3-related dwarfism in mouse model.

PubMed

Komla-Ebri, Davide; Dambroise, Emilie; Kramer, Ina; Benoist-Lasselin, Catherine; Kaci, Nabil; Le Gall, Cindy; Martin, Ludovic; Busca, Patricia; Barbault, Florent; Graus-Porta, Diana; Munnich, Arnold; Kneissel, Michaela; Di Rocco, Federico; Biosse-Duplan, Martin; Legeai-Mallet, Laurence

2016-05-02

Achondroplasia (ACH) is the most frequent form of dwarfism and is caused by gain-of-function mutations in the fibroblast growth factor receptor 3-encoding (FGFR3-encoding) gene. Although potential therapeutic strategies for ACH, which aim to reduce excessive FGFR3 activation, have emerged over many years, the use of tyrosine kinase inhibitor (TKI) to counteract FGFR3 hyperactivity has yet to be evaluated. Here, we have reported that the pan-FGFR TKI, NVP-BGJ398, reduces FGFR3 phosphorylation and corrects the abnormal femoral growth plate and calvaria in organ cultures from embryos of the Fgfr3Y367C/+ mouse model of ACH. Moreover, we demonstrated that a low dose of NVP-BGJ398, injected subcutaneously, was able to penetrate into the growth plate of Fgfr3Y367C/+ mice and modify its organization. Improvements to the axial and appendicular skeletons were noticeable after 10 days of treatment and were more extensive after 15 days of treatment that started from postnatal day 1. Low-dose NVP-BGJ398 treatment reduced intervertebral disc defects of lumbar vertebrae, loss of synchondroses, and foramen-magnum shape anomalies. NVP-BGJ398 inhibited FGFR3 downstream signaling pathways, including MAPK, SOX9, STAT1, and PLCγ, in the growth plates of Fgfr3Y367C/+ mice and in cultured chondrocyte models of ACH. Together, our data demonstrate that NVP-BGJ398 corrects pathological hallmarks of ACH and support TKIs as a potential therapeutic approach for ACH.

Effects of cholinesterase inhibitors on rat nicotinic receptor levels in vivo and in vitro

PubMed Central

Sabbagh, Marwan N.

2010-01-01

Cholinesterase inhibitors (ChEIs) are the mainstay of treatment for AD but differ by secondary mechanisms of action. We determine the effects of sub-chronic dosing of ChEIs on α7 and non-α7 nAChRs and determine if differences can be observed between them. Sprague–Dawley rats were administered donepezil, galantamine; rivastigmine at two doses each, in saline SQ twice daily or with nicotine (0.4 mg/kg) as a positive control. After 14 days the animals were sacrificed, and the levels of nAChRs were measured using [3H]-EPI to measure non-α7 nAChRs and [3H]-MLA to measure α7 nAChRs. In the cortex, all compounds tested at the higher doses significantly increased the levels of both [3H]-EPI and [3H]-MLA. In the hippocampus all compounds significantly increased [3H]-EPI but had no effect on [3H]-MLA binding. No effects were observed in the striatum with treatment. There were no differences observed among the ChEIs. In cell cultures, none of the ChEIs increased non-α7 or α7 receptor binding. Treatment with ChEIs result in similar increases in receptor levels which suggest that the increases in nAChRs may be due simply to the increases in synaptic levels of acetylcholine. PMID:18726544

21 CFR 172.165 - Quaternary ammonium chloride combination.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Quaternary ammonium chloride combination. 172.165... HUMAN CONSUMPTION Food Preservatives § 172.165 Quaternary ammonium chloride combination. The food additive, quaternary ammonium chloride combination, may be safely used in food in accordance with the...

Identification and Characterization of ML352: A Novel, Noncompetitive Inhibitor of the Presynaptic Choline Transporter

PubMed Central

2015-01-01

The high-affinity choline transporter (CHT) is the rate-limiting determinant of acetylcholine (ACh) synthesis, yet the transporter remains a largely undeveloped target for the detection and manipulation of synaptic cholinergic signaling. To expand CHT pharmacology, we pursued a high-throughput screen for novel CHT-targeted small molecules based on the electrogenic properties of transporter-mediated choline transport. In this effort, we identified five novel, structural classes of CHT-specific inhibitors. Chemical diversification and functional analysis of one of these classes identified ML352 as a high-affinity (Ki = 92 nM) and selective CHT inhibitor. At concentrations that fully antagonized CHT in transfected cells and nerve terminal preparations, ML352 exhibited no inhibition of acetylcholinesterase (AChE) or cholineacetyltransferase (ChAT) and also lacked activity at dopamine, serotonin, and norepinephrine transporters, as well as many receptors and ion channels. ML352 exhibited noncompetitive choline uptake inhibition in intact cells and synaptosomes and reduced the apparent density of hemicholinium-3 (HC-3) binding sites in membrane assays, suggesting allosteric transporter interactions. Pharmacokinetic studies revealed limited in vitro metabolism and significant CNS penetration, with features predicting rapid clearance. ML352 represents a novel, potent, and specific tool for the manipulation of CHT, providing a possible platform for the development of cholinergic imaging and therapeutic agents. PMID:25560927

Novel coumarin derivatives bearing N-benzyl pyridinium moiety: potent and dual binding site acetylcholinesterase inhibitors.

PubMed

Alipour, Masoumeh; Khoobi, Mehdi; Foroumadi, Alireza; Nadri, Hamid; Moradi, Alireza; Sakhteman, Amirhossein; Ghandi, Mehdi; Shafiee, Abbas

2012-12-15

A novel series of coumarin derivatives linked to benzyl pyridinium group were synthesized and biologically evaluated as inhibitors of both acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). The enzyme inhibitory activity of synthesized compounds was measured using colorimetric Ellman's method. It was revealed that compounds 3e, 3h, 3l, 3r and 3s have shown higher activity compared with donepezil hydrochloride as standard drug. Most of the compounds in these series had nanomolar range IC(50) in which compound 3r (IC(50) = 0.11 nM) was the most active compound against acetylcholinesterase enzyme. Copyright © 2012 Elsevier Ltd. All rights reserved.

Modulation of Cholinergic Pathways and Inflammatory Mediators in Blast-Induced Traumatic Brain Injury

DTIC Science & Technology

2013-01-01

matic brain injury (TBI). Centrally acting acetylcholinesterase (AChE) inhibitors are also being considered as potential therapeutic candidates...repeated blast exposures [12]. AChE inhibitors are possible therapeutic candidates against Alzheimer’s disease and TBI [13–15]. In this study, we...esterase inhibitor , as described earlier [12,17–19]. Brain AChE activity was expressed as milliunits/mg protein. 2.3. Microarray analysis Various

Natural products as sources of new lead compounds for the treatment of Alzheimer's disease.

PubMed

Huang, Ling; Su, Tao; Li, Xingshu

2013-01-01

Alzheimer's disease (AD) is the most prevalent form of dementia and affects approximately 24 million people worldwide. One possible approach for the treatment of this disease is the restoration of the level of acetylcholine (ACh) through the inhibition of acetylcholinesterase (AChE) with reversible inhibitors. Naturally occurring alkaloids are an important source of AChE inhibitors. Galantamine and huperzine A have been used for the clinical treatment of AD patients. In this review, we summarise the natural products and their derivatives that were reported to act as AChE inhibitors for the treatment of AD in 2010-2013. Several characteristics were summarised from the literature results: 1) Amongst all of the natural products with AChE inhibitory activity, alkaloids appear to be the most promising compound class. 2) Coumarins, flavonoids, stilbenes, and other natural products are also important AChE inhibitors from natural products. Among these inhibitors, 146 (IC50 = 0.573 µM) was identified as the most potent AChE inhibitor. 3) A coumarin derivative (117, IC50 = 0.11 nM) exhibited more than 100-fold superior activity compared with the reference drug donepezil hydrochloride (IC50 = 14 nM). In conclusion, natural products and their derivatives are promising leads for the development of new drugs for the future treatment of AD.

Congo red modulates ACh-induced Ca2+ oscillations in single pancreatic acinar cells of mice

PubMed Central

Huang, Ze-bing; Wang, Hai-yan; Sun, Na-na; Wang, Jing-ke; Zhao, Meng-qin; Shen, Jian-xin; Gao, Ming; Hammer, Ronald P; Fan, Xue-gong; Wu, Jie

2014-01-01

Aim: Congo red, a secondary diazo dye, is usually used as an indicator for the presence of amyloid fibrils. Recent studies show that congo red exerts neuroprotective effects in a variety of models of neurodegenerative diseases. However, its pharmacological profile remains unknown. In this study, we investigated the effects of congo red on ACh-induced Ca2+ oscillations in mouse pancreatic acinar cells in vitro. Methods: Acutely dissociated pancreatic acinar cells of mice were prepared. A U-tube drug application system was used to deliver drugs into the bath. Intracellular Ca2+ oscillations were monitored by whole-cell recording of Ca2+-activated Cl− currents and by using confocal Ca2+ imaging. For intracellular drug application, the drug was added in pipette solution and diffused into cell after the whole-cell configuration was established. Results: Bath application of ACh (10 nmol/L) induced typical Ca2+ oscillations in dissociated pancreatic acinar cells. Addition of congo red (1, 10, 100 μmol/L) dose-dependently enhanced Ach-induced Ca2+ oscillations, but congo red alone did not induce any detectable response. Furthermore, this enhancement depended on the concentrations of ACh: congo red markedly enhanced the Ca2+ oscillations induced by ACh (10–30 nmol/L), but did not alter the Ca2+ oscillations induced by ACh (100–10000 nmol/L). Congo red also enhanced the Ca2+ oscillations induced by bath application of IP3 (30 μmol/L). Intracellular application of congo red failed to alter ACh-induced Ca2+ oscillations. Conclusion: Congo red significantly modulates intracellular Ca2+ signaling in pancreatic acinar cells, and this pharmacological effect should be fully considered when developing congo red as a novel therapeutic drug. PMID:25345744

Acetylcholinesterase inhibitory properties of some benzoic acid derivatives

NASA Astrophysics Data System (ADS)

Yildiz, Melike; Kiliç, Deryanur; Ünver, Yaǧmur; Şentürk, Murat; Askin, Hakan; Küfrevioǧlu, Ömer Irfan

2016-04-01

Acetylcholinesterase (AChE) hydrolyses the neurotransmitter acetylcholine to acetic acid and choline. AChE inhibitors are used in treatment of several neurodegeneartive disorder and Alzheimer's disease. In the present study, inhibition of AChE with some benzoic acid derivatives were investigated. 3-Chloro-benzoic acid (1), 2-hydroxy-5-sulfobenzoic acid (2), 2-(sulfooxy) benzoic acid (3), 2-hydroxybenzoic acid (4), 2,3-dimethoxybenzoic (5), and 3,4,5-trimethoxybenzoic (6) were calculated IC50 values AChE enzyme. Kinetic investigations showed that similarly to AChE inhibitors. Benzoic acid derivatives (1-6) investigated are encouraging agents which may be used as lead molecules in order to derivative novel AChE inhibitors that might be useful in medical applications.

Acetylcholine esterase inhibitors and melanin synthesis inhibitors from Salvia officinalis.

PubMed

Sallam, Amal; Mira, Amira; Ashour, Ahmed; Shimizu, Kuniyoshi

2016-09-15

Salvia officinalis is a traditionally used herb with a wide range of medicinal applications. Many phytoconstituents have been isolated from S. officinalis, mainly phenolic diterpenes, which possess many biological activities. This study aimed to evaluate the ability of the phenolic diterpenes of S. officinalis to inhibit acetylcholine esterase (AChE) as well as their ability to inhibit melanin biosynthesis in B16 melanoma cells. The phenolic diterpenes isolated from the aerial parts of S. officinalis were tested for their effect on melanin biosynthesis in B16 melanoma cell lines. They were also tested for their ability to inhibit AChE using Ellman's method. Moreover, a molecular docking experiment was used to investigate the binding affinity of the isolated phenolic diterpenes to the amino acid residues at the active sites of AChE. Seven phenolic diterpenes-sageone, 12-methylcarnosol, carnosol, 7b-methoxyrosmanol, 7a-methoxyrosmanol, isorosmanol and epirosmanol-were isolated from the methanolic extract of the aerial parts of S. officinalis. Isorosmanol showed a melanin-inhibiting activity as potent as that of arbutin. Compounds 7a-methoxyrosmanol and isorosmanol inhibited AChE activity by 50% and 65%, respectively, at a concentration of 500 µM. The results suggest that isorosmanol is a promising natural compound for further studies on development of new medications which might be useful in ageing disorders such as the declining of cognitive functions and hyperpigmentation. Copyright © 2016 Elsevier GmbH. All rights reserved.

Acetylcholinesterase inhibitors for electroconvulsive therapy-induced cognitive side effects: a systematic review.

PubMed

Henstra, Marieke J; Jansma, Elise P; van der Velde, Nathalie; Swart, Eleonora L; Stek, Max L; Rhebergen, Didi

2017-05-01

Electroconvulsive therapy (ECT) is an effective treatment for severe late-life depression; however, ECT-induced cognitive side effects frequently occur. The cholinergic system is thought to play an important role in the pathogenesis. We systematically reviewed the evidence for acetylcholinesterase inhibitors (Ache-I) to prevent or reduce ECT-induced cognitive side effects. A systematic search was performed in Pubmed, EMBASE, PsychINFO, and the Cochrane database to identify clinical trials investigating the effect of Ache-I on ECT-induced cognitive side effects. Key search terms included all synonyms for ECT and Ache-I. Risk of bias assessment was conducted by using the Cochrane Collaboration's tool. Five clinical trials were eligible for inclusion. All studies focused on cognitive functioning as primary endpoint, but assessment of cognitive functioning varied widely in time point of assessment and in cognitive tests that were used. There was also great variety in study medication, route and time of administration and dosages, duration of drug administration, and ECT techniques. Finally, only two out of five studies were considered at low risk of bias. Despite the aforementioned shortcomings, without exception, all studies demonstrated significantly better cognitive performance in individuals treated with Ache-I. Despite large heterogeneity in studies, Ache-I appear to have beneficial effects on ECT-induced cognitive side effects, supporting an association with the cholinergic system in ECT-induced cognitive impairment. Methodological sound studies controlling for putative confounders are warranted. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Tyrosine kinase inhibitor NVP-BGJ398 functionally improves FGFR3-related dwarfism in mouse model

PubMed Central

Dambroise, Emilie; Kramer, Ina; Benoist-Lasselin, Catherine; Kaci, Nabil; Le Gall, Cindy; Martin, Ludovic; Busca, Patricia; Barbault, Florent; Graus-Porta, Diana; Munnich, Arnold; Kneissel, Michaela; Di Rocco, Federico; Biosse-Duplan, Martin

2016-01-01

Achondroplasia (ACH) is the most frequent form of dwarfism and is caused by gain-of-function mutations in the fibroblast growth factor receptor 3–encoding (FGFR3-encoding) gene. Although potential therapeutic strategies for ACH, which aim to reduce excessive FGFR3 activation, have emerged over many years, the use of tyrosine kinase inhibitor (TKI) to counteract FGFR3 hyperactivity has yet to be evaluated. Here, we have reported that the pan-FGFR TKI, NVP-BGJ398, reduces FGFR3 phosphorylation and corrects the abnormal femoral growth plate and calvaria in organ cultures from embryos of the Fgfr3Y367C/+ mouse model of ACH. Moreover, we demonstrated that a low dose of NVP-BGJ398, injected subcutaneously, was able to penetrate into the growth plate of Fgfr3Y367C/+ mice and modify its organization. Improvements to the axial and appendicular skeletons were noticeable after 10 days of treatment and were more extensive after 15 days of treatment that started from postnatal day 1. Low-dose NVP-BGJ398 treatment reduced intervertebral disc defects of lumbar vertebrae, loss of synchondroses, and foramen-magnum shape anomalies. NVP-BGJ398 inhibited FGFR3 downstream signaling pathways, including MAPK, SOX9, STAT1, and PLCγ, in the growth plates of Fgfr3Y367C/+ mice and in cultured chondrocyte models of ACH. Together, our data demonstrate that NVP-BGJ398 corrects pathological hallmarks of ACH and support TKIs as a potential therapeutic approach for ACH. PMID:27064282

Inhibitors of soluble epoxide hydrolase minimize ischemia-reperfusion-induced cardiac damage in normal, hypertensive, and diabetic rats.

PubMed

Islam, Oliul; Patil, Prashanth; Goswami, Sumanta K; Razdan, Rema; Inamdar, Mohammed N; Rizwan, Mohammed; Mathew, Jubin; Inceoglu, Bora; Stephen Lee, Kin S; Hwang, Sung H; Hammock, Bruce D

2017-06-01

We designed a study to evaluate the cardioprotective effect of two soluble epoxide hydrolase (sEH) inhibitors, 1-(1-propanoylpiperidin-4-yl)-3-(4-trifluoromethoxy)phenyl)urea (TPPU) and trans-4-{4-[3-(4-trifluoromethoxyphenyl)-ureido]cyclohexyloxy}benzoic acid (t-TUCB), in ischemia-reperfusion (IR) model. Cardioprotective effects of the sEH inhibitors were evaluated against IR-induced myocardial damage in hearts from normal, hypertensive, and diabetic rats using Langendorff's apparatus. In addition, the effect of sEH inhibitors on endothelial function was evaluated in vitro and ex vivo using isolated rat thoracic aorta. Ischemia-reperfusion (IR) increased the myocardial damage in hearts from normal rats. IR-induced myocardial damage was augmented in hearts isolated from hypertensive and diabetic rats. Myocardial damage as evident from increase in the activities of lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB) in heart perfusate was associated with significant decrease in the heart rate and developed tension, and increase in the resting tension in isolated heart. Both sEH inhibitors protected the heart in normal, hypertensive, and diabetic rats subjected to IR injury. The sEH inhibitor t-TUCB relaxed phenylephrine precontracted aorta from normal rats. Relaxant effect of acetylcholine (ACh) was reduced in aortas from diabetic and hypertensive rats compared to normal rats. Pretreatment of sEH inhibitors to diabetic and hypertensive rats increased relaxant effect of ACh on aortas isolated from these rats. Prophylactic treatment with sEH inhibitors decreased myocardial damage due to IR, hypertension and diabetes, and decreased endothelial dysfunction created by diabetes and hypertension. Therefore, inhibitors of sEH are useful probes to study cardiovascular pathology, and inhibition of the sEH is a potential approach in the management of IR-induced cardiac damage and endothelial dysfunction-related cardiovascular disorders. © 2017 John Wiley & Sons Ltd.

[125I]Iodo-ASEM, a specific in vivo radioligand for α7-nAChR

PubMed Central

Gao, Yongjun; Mease, Ronnie C.; Olson, Thao T.; Kellar, Kenneth J.; Dannals, Robert F.; Pomper, Martin G.; Horti, Andrew G.

2014-01-01

[125I]Iodo-ASEM, a new radioligand with high affinity and selectivity for α7-nAChRs (Ki = 0.5 nM; α7/α4β2 = 3,414), has been synthesized in radiochemical yield of 33 ± 6% from the corresponding di-butyltriazene derivative and at high specific radioactivity (1,600 Ci/mmol; 59.2 MBq/μmol). [125I]Iodo-ASEM readily entered the brains of normal CD-1 mice and specifically and selectively labeled cerebral α7-nAChRs. [125I]iodo-ASEM is a new useful tool for studying α7-nAChR. PMID:25687449

O-Hydroxyl- or o-amino benzylamine-tacrine hybrids: multifunctional biometals chelators, antioxidants, and inhibitors of cholinesterase activity and amyloid-β aggregation.

PubMed

Mao, Fei; Huang, Ling; Luo, Zonghua; Liu, Anqiu; Lu, Chuanjun; Xie, Zhiyong; Li, Xingshu

2012-10-01

In an effort to identify novel multifunctional drug candidates for the treatment of Alzheimer's disease (AD), a series of hybrid molecules were synthesised by reacting N-(aminoalkyl)tacrine with salicylic aldehyde or derivatives of 2-aminobenzaldehyde. These compounds were then evaluated as multifunctional anti-Alzheimer's disease agents. All of the hybrids are potential biometal chelators, and in addition, most of them were better antioxidants and inhibitors of cholinesterases and amyloid-β (Aβ) aggregation than the lead compound tacrine. Compound 7c has the potential to be a candidate for AD therapy: it is a much better inhibitor of acetylcholinesterase (AChE) than tacrine (IC(50): 0.55 nM vs 109 nM), has good biometal chelation ability, is able to inhibit Aβ aggregation and has moderate antioxidant activity (1.22 Trolox equivalents). Copyright © 2012 Elsevier Ltd. All rights reserved.

The α3β4* nicotinic ACh receptor subtype mediates physical dependence to morphine: mouse and human studies.

PubMed

Muldoon, P P; Jackson, K J; Perez, E; Harenza, J L; Molas, S; Rais, B; Anwar, H; Zaveri, N T; Maldonado, R; Maskos, U; McIntosh, J M; Dierssen, M; Miles, M F; Chen, X; De Biasi, M; Damaj, M I

2014-08-01

Recent data have indicated that α3β4* neuronal nicotinic (n) ACh receptors may play a role in morphine dependence. Here we investigated if nACh receptors modulate morphine physical withdrawal. To assess the role of α3β4* nACh receptors in morphine withdrawal, we used a genetic correlation approach using publically available datasets within the GeneNetwork web resource, genetic knockout and pharmacological tools. Male and female European-American (n = 2772) and African-American (n = 1309) subjects from the Study of Addiction: Genetics and Environment dataset were assessed for possible associations of polymorphisms in the 15q25 gene cluster and opioid dependence. BXD recombinant mouse lines demonstrated an increased expression of α3, β4 and α5 nACh receptor mRNA in the forebrain and midbrain, which significantly correlated with increased defecation in mice undergoing morphine withdrawal. Mice overexpressing the gene cluster CHRNA5/A3/B4 exhibited increased somatic signs of withdrawal. Furthermore, α5 and β4 nACh receptor knockout mice expressed decreased somatic withdrawal signs compared with their wild-type counterparts. Moreover, selective α3β4* nACh receptor antagonists, α-conotoxin AuIB and AT-1001, attenuated somatic signs of morphine withdrawal in a dose-related manner. In addition, two human datasets revealed a protective role for variants in the CHRNA3 gene, which codes for the α3 nACh receptor subunit, in opioid dependence and withdrawal. In contrast, we found that the α4β2* nACh receptor subtype is not involved in morphine somatic withdrawal signs. Overall, our findings suggest an important role for the α3β4* nACh receptor subtype in morphine physical dependence. © 2014 The British Pharmacological Society.

The α3β4* nicotinic ACh receptor subtype mediates physical dependence to morphine: mouse and human studies

PubMed Central

Muldoon, P P; Jackson, K J; Perez, E; Harenza, J L; Molas, S; Rais, B; Anwar, H; Zaveri, N T; Maldonado, R; Maskos, U; McIntosh, J M; Dierssen, M; Miles, M F; Chen, X; De Biasi, M; Damaj, M I

2014-01-01

BACKGROUND AND PURPOSE Recent data have indicated that α3β4* neuronal nicotinic (n) ACh receptors may play a role in morphine dependence. Here we investigated if nACh receptors modulate morphine physical withdrawal. EXPERIMENTAL APPROACHES To assess the role of α3β4* nACh receptors in morphine withdrawal, we used a genetic correlation approach using publically available datasets within the GeneNetwork web resource, genetic knockout and pharmacological tools. Male and female European-American (n = 2772) and African-American (n = 1309) subjects from the Study of Addiction: Genetics and Environment dataset were assessed for possible associations of polymorphisms in the 15q25 gene cluster and opioid dependence. KEY RESULTS BXD recombinant mouse lines demonstrated an increased expression of α3, β4 and α5 nACh receptor mRNA in the forebrain and midbrain, which significantly correlated with increased defecation in mice undergoing morphine withdrawal. Mice overexpressing the gene cluster CHRNA5/A3/B4 exhibited increased somatic signs of withdrawal. Furthermore, α5 and β4 nACh receptor knockout mice expressed decreased somatic withdrawal signs compared with their wild-type counterparts. Moreover, selective α3β4* nACh receptor antagonists, α-conotoxin AuIB and AT-1001, attenuated somatic signs of morphine withdrawal in a dose-related manner. In addition, two human datasets revealed a protective role for variants in the CHRNA3 gene, which codes for the α3 nACh receptor subunit, in opioid dependence and withdrawal. In contrast, we found that the α4β2* nACh receptor subtype is not involved in morphine somatic withdrawal signs. CONCLUSION AND IMPLICATIONS Overall, our findings suggest an important role for the α3β4* nACh receptor subtype in morphine physical dependence. PMID:24750073

Design, facile synthesis, and evaluation of novel spiro- and pyrazolo[1,5-c]quinazolines as cholinesterase inhibitors: Molecular docking and MM/GBSA studies.

PubMed

Gálvez, Jaime; Polo, Stivens; Insuasty, Braulio; Gutiérrez, Margarita; Cáceres, Daniela; Alzate-Morales, Jans H; De-la-Torre, Pedro; Quiroga, Jairo

2018-03-07

Given the wide spectrum of biological uses of pyrazolo[1,5-c]quinazoline and spiro-quinazoline derivatives as anticancer, anti-inflammatory analgesic agents, and their therapeutic applications in neurodegenerative disorders, it is compulsory to find easy, efficient, and simple methods to obtain and chemically diversify these families of compounds, thereby improving their biological applications. In this paper, we report the design and eco-friendly two-step synthesis of novel, fused spiro-pyrazolo[1,5-c]quinazoline derivatives as cholinesterase inhibitors. In addition, we studied their protein-ligand interactions via molecular docking and MM/GBSA calculations for a further rational design of more potent inhibitors. In first step, 2-(1H-pyrazol-5-yl)anilines were obtained through microwave (MW) assisted solvent-free/catalyst-free conditions and the second step involved the synthesis of the spiro-pyrazolo[1,5-c]quinazolines by a cyclocondensation reaction between 2-(1H-pyrazol-5-yl)anilines and cyclic ketones, or acetophenones, using stirring at room temperature. The compounds were obtained in high purity, good yields (50-97%), and at varying reaction times. The spiro-compounds were evaluated as acetylcholinesterase and butyrylcholinesterase inhibitors (AChEIs/BuChEIs) respectively, and the most potent compound exhibited a moderate AChE inhibitory activity (5f: IC 50  = 84 μM). Molecular docking studies indicated that the binding mode of the compound 5f share common characteristics with the galantamine/donepezil-AChE complexes. Moreover, free binding energy (ΔG) calculations showed a good agreement with the experimental biological activity values. Our theoretical results indicated that halogen bond interactions could be involved with differential potency of these compounds and provide a new starting point to design novel pyrazolo[1,5-c]quinazolines as new anti-Alzheimer agents. Copyright © 2018. Published by Elsevier Ltd.

Inhibitors of histone demethylation and histone deacetylation cooperate in regulating gene expression and inhibiting growth in human breast cancer cells

PubMed Central

Vasilatos, Shauna N.; Boric, Lamia; Shaw, Patrick G.; Davidson, Nancy E.

2013-01-01

Abnormal activities of histone lysine demethylases (KDMs) and lysine deacetylases (HDACs) are associated with aberrant gene expression in breast cancer development. However, the precise molecular mechanisms underlying the crosstalk between KDMs and HDACs in chromatin remodeling and regulation of gene transcription are still elusive. In this study, we showed that treatment of human breast cancer cells with inhibitors targeting the zinc cofactor dependent class I/II HDAC, but not NAD+ dependent class III HDAC, led to significant increase of H3K4me2 which is a specific substrate of histone lysine-specific demethylase 1 (LSD1) and a key chromatin mark promoting transcriptional activation. We also demonstrated that inhibition of LSD1 activity by a pharmacological inhibitor, pargyline, or siRNA resulted in increased acetylation of H3K9 (AcH3K9). However, siRNA knockdown of LSD2, a homolog of LSD1, failed to alter the level of AcH3K9, suggesting that LSD2 activity may not be functionally connected with HDAC activity. Combined treatment with LSD1 and HDAC inhibitors resulted in enhanced levels of H3K4me2 and AcH3K9, and exhibited synergistic growth inhibition of breast cancer cells. Finally, microarray screening identified a unique subset of genes whose expression was significantly changed by combination treatment with inhibitors of LSD1 and HDAC. Our study suggests that LSD1 intimately interacts with histone deacetylases in human breast cancer cells. Inhibition of histone demethylation and deacetylation exhibits cooperation and synergy in regulating gene expression and growth inhibition, and may represent a promising and novel approach for epigenetic therapy of breast cancer. PMID:21452019

Nicotinic Acetylcholine Receptor (nAChR) Dependent Chorda Tympani Taste Nerve Responses to Nicotine, Ethanol and Acetylcholine.

PubMed

Ren, Zuo Jun; Mummalaneni, Shobha; Qian, Jie; Baumgarten, Clive M; DeSimone, John A; Lyall, Vijay

2015-01-01

Nicotine elicits bitter taste by activating TRPM5-dependent and TRPM5-independent but neuronal nAChR-dependent pathways. The nAChRs represent common targets at which acetylcholine, nicotine and ethanol functionally interact in the central nervous system. Here, we investigated if the nAChRs also represent a common pathway through which the bitter taste of nicotine, ethanol and acetylcholine is transduced. To this end, chorda tympani (CT) taste nerve responses were monitored in rats, wild-type mice and TRPM5 knockout (KO) mice following lingual stimulation with nicotine free base, ethanol, and acetylcholine, in the absence and presence of nAChR agonists and antagonists. The nAChR modulators: mecamylamine, dihydro-β-erythroidine, and CP-601932 (a partial agonist of the α3β4* nAChR), inhibited CT responses to nicotine, ethanol, and acetylcholine. CT responses to nicotine and ethanol were also inhibited by topical lingual application of 8-chlorophenylthio (CPT)-cAMP and loading taste cells with [Ca2+]i by topical lingual application of ionomycin + CaCl2. In contrast, CT responses to nicotine were enhanced when TRC [Ca2+]i was reduced by topical lingual application of BAPTA-AM. In patch-clamp experiments, only a subset of isolated rat fungiform taste cells exposed to nicotine responded with an increase in mecamylamine-sensitive inward currents. We conclude that nAChRs expressed in a subset of taste cells serve as common receptors for the detection of the TRPM5-independent bitter taste of nicotine, acetylcholine and ethanol.

Nicotinic Acetylcholine Receptor (nAChR) Dependent Chorda Tympani Taste Nerve Responses to Nicotine, Ethanol and Acetylcholine

PubMed Central

Ren, Zuo Jun; Mummalaneni, Shobha; Qian, Jie; Baumgarten, Clive M.; DeSimone, John A.; Lyall, Vijay

2015-01-01

Nicotine elicits bitter taste by activating TRPM5-dependent and TRPM5-independent but neuronal nAChR-dependent pathways. The nAChRs represent common targets at which acetylcholine, nicotine and ethanol functionally interact in the central nervous system. Here, we investigated if the nAChRs also represent a common pathway through which the bitter taste of nicotine, ethanol and acetylcholine is transduced. To this end, chorda tympani (CT) taste nerve responses were monitored in rats, wild-type mice and TRPM5 knockout (KO) mice following lingual stimulation with nicotine free base, ethanol, and acetylcholine, in the absence and presence of nAChR agonists and antagonists. The nAChR modulators: mecamylamine, dihydro-β-erythroidine, and CP-601932 (a partial agonist of the α3β4* nAChR), inhibited CT responses to nicotine, ethanol, and acetylcholine. CT responses to nicotine and ethanol were also inhibited by topical lingual application of 8-chlorophenylthio (CPT)-cAMP and loading taste cells with [Ca2+]i by topical lingual application of ionomycin + CaCl2. In contrast, CT responses to nicotine were enhanced when TRC [Ca2+]i was reduced by topical lingual application of BAPTA-AM. In patch-clamp experiments, only a subset of isolated rat fungiform taste cells exposed to nicotine responded with an increase in mecamylamine-sensitive inward currents. We conclude that nAChRs expressed in a subset of taste cells serve as common receptors for the detection of the TRPM5-independent bitter taste of nicotine, acetylcholine and ethanol. PMID:26039516

Novel tacrine-1,2,3-triazole hybrids: In vitro, in vivo biological evaluation and docking study of cholinesterase inhibitors.

PubMed

Najafi, Zahra; Mahdavi, Mohammad; Saeedi, Mina; Karimpour-Razkenari, Elahe; Asatouri, Raymond; Vafadarnejad, Fahimeh; Moghadam, Farshad Homayouni; Khanavi, Mahnaz; Sharifzadeh, Mohammad; Akbarzadeh, Tahmineh

2017-01-05

A new series of tacrine-1,2,3-triazole hybrids were designed, synthesized, and evaluated as potent dual cholinesterase inhibitors. Most of synthesized compounds showed good in vitro inhibitory activities toward both acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Among them, 7-chloro-N-((1-(4-methoxybenzyl)-1H-1,2,3-triazol-4-yl)methyl)-1,2,3,4-tetrahydroacridin-9-amine (5l) was found to be the most potent anti-AChE derivative (IC 50  = 0.521 μM) and N-((1-(4-methoxybenzyl)-1H-1,2,3-triazol-4-yl)methyl)-1,2,3,4-tetrahydroacridin-9-amine (5j) demonstrated the best anti-BChE activity (IC 50  = 0.055 μM). In vivo studies of compound 5l in Morris water maze task confirmed memory improvement in scopolamine-induced impairment. Also, molecular modeling and kinetic studies showed that compounds 5l and 5j bound simultaneously to the peripheral anionic site (PAS) and catalytic sites (CS) of the AChE and BChE. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Cost-utility analysis of memantine extended release added to cholinesterase inhibitors compared to cholinesterase inhibitor monotherapy for the treatment of moderate-to-severe dementia of the Alzheimer's type in the US.

PubMed

Saint-Laurent Thibault, Catherine; Özer Stillman, Ipek; Chen, Stephanie; Getsios, Denis; Proskorovsky, Irina; Hernandez, Luis; Dixit, Shailja

2015-01-01

This study evaluates the cost-effectiveness of memantine extended release (ER) as an add-on therapy to acetylcholinesterase inhibitor (AChEI) [combination therapy] for treatment of patients with moderate-to-severe Alzheimer's disease (AD) from both a healthcare payer and a societal perspective over 3 years when compared to AChEI monotherapy in the US. A phase III trial evaluated the efficacy and safety of memantine ER for treatment of AD patients taking an AChEI. The analysis assessed the long-term costs and health outcomes using an individual patient simulation in which AD progression is modeled in terms of cognition, behavior, and functioning changes. Input parameters are based on patient-level trial data, published literature, and publicly available data sources. Changes in anti-psychotic medication use are incorporated based on a published retrospective cohort study. Costs include drug acquisition and monitoring, total AD-related medical care, and informal care associated with caregiver time. Incremental cost-utility ratio (ICUR), life years, care time for caregiver, time in community and institution, time on anti-psychotics, time by disease severity, and time without severe symptoms are reported. Costs and health outcomes are discounted at 3% per annum. Considering a societal perspective over 3 years, this analysis shows that memantine ER combined with an AChEI provides better clinical outcomes and lower costs than AChEI monotherapy. Discounted average savings were estimated at $18,355 and $20,947 per patient and quality-adjusted life-years (QALYs) increased by an average of 0.12 and 0.13 from a societal and healthcare payer perspective, respectively. Patients on combination therapy spent an average of 4 months longer living at home and spend less time in moderate-severe and severe stages of the disease. Combination therapy for patients with moderate-to-severe AD is a cost-effective treatment compared to AChEI monotherapy in the US.

α7-nAChR Knockout Mice Decreases Biliary Hyperplasia and Liver Fibrosis in Cholestatic Bile-Duct Ligated Mice.

PubMed

Ehrlich, Laurent; O'Brien, April; Hall, Chad; White, Tori; Chen, Lixian; Wu, Nan; Venter, Julie; Scrushy, Marinda; Mubarak, Muhammad; Meng, Fanyin; Dostal, David; Wu, Chaodong; Lairmore, Terry C; Alpini, Gianfranco; Glaser, Shannon

2018-03-26

α7-nAChR is a nicotinic acetylcholine receptor (specifically expressed on hepatic stellate cells, Kupffer cells, and cholangiocytes) that regulates inflammation and apoptosis in the liver. Thus, targeting α7-nAChR may be therapeutic in biliary diseases. Bile-duct ligation (BDL) was performed on wild-type (WT) and α7-nAChR-/- mice. We first evaluated the expression of α7-nAChR by immunohistochemistry (IHC) in liver sections. IHC was also performed to assess intrahepatic bile-duct mass (IBDM), and Sirius Red staining was performed to quantify the amount of collagen deposition. Immunofluorescence was performed to assess co-localization of α7-nAChR with bile ducts (co-stained with CK-19) and hepatic stellate cells (HSCs) (co-stained with desmin). The mRNA expression of α7-nAChR, Ki67/PCNA (proliferation), fibrosis genes (TGF-β1, Fibronectin-1, Col1α1, and α-SMA), and inflammatory markers (IL-6, IL-1β, and TNFα) was measured by real-time PCR. Biliary TGF-β1 and hepatic CD68 (Kupffer cell marker) expression was assessed using IHC. α7-nAChR immunoreactivity was observed in both bile ducts and HSCs and increased following BDL. α7-nAChR-/- BDL mice exhibited decreased: (i) bile duct mass, liver fibrosis, and inflammation; and (ii) immunoreactivity of TGF-1 as well as expression of fibrosis genes compared to WT BDL mice. α7-nAChR activation triggers biliary proliferation and liver fibrosis and may be a therapeutic target in managing extra-hepatic biliary obstruction.

Efficient method for high-throughput virtual screening based on flexible docking: discovery of novel acetylcholinesterase inhibitors.

PubMed

Mizutani, Miho Yamada; Itai, Akiko

2004-09-23

A method of easily finding ligands, with a variety of core structures, for a given target macromolecule would greatly contribute to the rapid identification of novel lead compounds for drug development. We have developed an efficient method for discovering ligand candidates from a number of flexible compounds included in databases, when the three-dimensional (3D) structure of the drug target is available. The method, named ADAM&EVE, makes use of our automated docking method ADAM, which has already been reported. Like ADAM, ADAM&EVE takes account of the flexibility of each molecule in databases, by exploring the conformational space fully and continuously. Database screening has been made much faster than with ADAM through the tuning of parameters, so that computational screening of several hundred thousand compounds is possible in a practical time. Promising ligand candidates can be selected according to various criteria based on the docking results and characteristics of compounds. Furthermore, we have developed a new tool, EVE-MAKE, for automatically preparing the additional compound data necessary for flexible docking calculation, prior to 3D database screening. Among several successful cases of lead discovery by ADAM&EVE, the finding of novel acetylcholinesterase (AChE) inhibitors is presented here. We performed a virtual screening of about 160 000 commercially available compounds against the X-ray crystallographic structure of AChE. Among 114 compounds that could be purchased and assayed, 35 molecules with various core structures showed inhibitory activities with IC(50) values less than 100 microM. Thirteen compounds had IC(50) values between 0.5 and 10 microM, and almost all their core structures are very different from those of known inhibitors. The results demonstrate the effectiveness and validity of the ADAM&EVE approach and provide a starting point for development of novel drugs to treat Alzheimer's disease.

Synthesis and biological evaluation of a series of dithiocarbamates as new cholinesterase inhibitors.

PubMed

Altıntop, Mehlika D; Gurkan-Alp, A Selen; Ozkay, Yusuf; Kaplancıklı, Zafer A

2013-08-01

In the present paper, a novel series of dithiocarbamates was synthesized via the treatment of 4-(trifluoromethyl)benzyl chloride with appropriate sodium salts of N,N-disubstituted dithiocarbamic acids. The chemical structures of the compounds were elucidated by (1) H NMR, mass spectral data, and elemental analyses. Each derivative was evaluated for its ability to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) using a modification of Ellman's spectrophotometric method. The most potent AChE inhibitor was found as compound 2g (IC50  = 0.53 ± 0.001 µM) followed by compounds 2f (IC50  = 0.74 ± 0.001 µM) and 2j (IC50  = 0.89 ± 0.002 µM) when compared with donepezil (IC50  = 0.048 ± 0.001 µM). Compounds 2f and 2g were more effective than donepezil (IC50  = 7.88 ± 0.52 µM) on BuChE inhibition. Compounds 2f and 2g exhibited the inhibitory effect on BuChE with IC50 values of 1.39 ± 0.041 and 3.64 ± 0.072 µM, respectively. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Roles for N-terminal Extracellular Domains of Nicotinic Acetylcholine Receptor (nAChR) β3 Subunits in Enhanced Functional Expression of Mouse α6β2β3- and α6β4β3-nAChRs*

PubMed Central

Dash, Bhagirathi; Li, Ming D.; Lukas, Ronald J.

2014-01-01

Functional heterologous expression of naturally expressed mouse α6*-nicotinic acetylcholine receptors (mα6*-nAChRs; where “*” indicates the presence of additional subunits) has been difficult. Here we expressed and characterized wild-type (WT), gain-of-function, chimeric, or gain-of-function chimeric nAChR subunits, sometimes as hybrid nAChRs containing both human (h) and mouse (m) subunits, in Xenopus oocytes. Hybrid mα6mβ4hβ3- (∼5–8-fold) or WT mα6mβ4mβ3-nAChRs (∼2-fold) yielded higher function than mα6mβ4-nAChRs. Function was not detected when mα6 and mβ2 subunits were expressed together or in the additional presence of hβ3 or mβ3 subunits. However, function emerged upon expression of mα6mβ2mβ3V9′S-nAChRs containing β3 subunits having gain-of-function V9′S (valine to serine at the 9′-position) mutations in transmembrane domain II and was further elevated 9-fold when hβ3V9′S subunits were substituted for mβ3V9′S subunits. Studies involving WT or gain-of-function chimeric mouse/human β3 subunits narrowed the search for domains that influence functional expression of mα6*-nAChRs. Using hβ3 subunits as templates for site-directed mutagenesis studies, substitution with mβ3 subunit residues in extracellular N-terminal domain loops “C” (Glu221 and Phe223), “E” (Ser144 and Ser148), and “β2-β3” (Gln94 and Glu101) increased function of mα6mβ2*- (∼2–3-fold) or mα6mβ4* (∼2–4-fold)-nAChRs. EC50 values for nicotine acting at mα6mβ4*-nAChR were unaffected by β3 subunit residue substitutions in loop C or E. Thus, amino acid residues located in primary (loop C) or complementary (loops β2-β3 and E) interfaces of β3 subunits are some of the molecular impediments for functional expression of mα6mβ2β3- or mα6mβ4β3-nAChRs. PMID:25028511

Calcium Influx and Release Cooperatively Regulate AChR Patterning and Motor Axon Outgrowth during Neuromuscular Junction Formation.

PubMed

Kaplan, Mehmet Mahsum; Sultana, Nasreen; Benedetti, Ariane; Obermair, Gerald J; Linde, Nina F; Papadopoulos, Symeon; Dayal, Anamika; Grabner, Manfred; Flucher, Bernhard E

2018-06-26

Formation of synapses between motor neurons and muscles is initiated by clustering of acetylcholine receptors (AChRs) in the center of muscle fibers prior to nerve arrival. This AChR patterning is considered to be critically dependent on calcium influx through L-type channels (Ca V 1.1). Using a genetic approach in mice, we demonstrate here that either the L-type calcium currents (LTCCs) or sarcoplasmic reticulum (SR) calcium release is necessary and sufficient to regulate AChR clustering at the onset of neuromuscular junction (NMJ) development. The combined lack of both calcium signals results in loss of AChR patterning and excessive nerve branching. In the absence of SR calcium release, the severity of synapse formation defects inversely correlates with the magnitude of LTCCs. These findings highlight the importance of activity-dependent calcium signaling in early neuromuscular junction formation and indicate that both LTCC and SR calcium release individually support proper innervation of muscle by regulating AChR patterning and motor axon outgrowth. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Synthesis, crystal structure determination, biological screening and docking studies of N1-substituted derivatives of 2,3-dihydroquinazolin-4(1H)-one as inhibitors of cholinesterases.

PubMed

Sultana, Nargis; Sarfraz, Muhammad; Tanoli, Saba Tahir; Akram, Muhammad Safwan; Sadiq, Abdul; Rashid, Umer; Tariq, Muhammad Ilyas

2017-06-01

Pursuing the strategy of developing potent AChE inhibitors, we attempted to carry out the N 1 -substitution of 2,3-dihydroquinazolin-4(1H)-one core. A set of 32 N-alkylated/benzylated quinazoline derivatives were synthesized, characterized and evaluated for their inhibition against cholinesterases. N-alkylation of the series of the compounds reported previously (N-unsubstituted) resulted in improved activity. All the compounds showed inhibition of both enzymes in the micromolar to submicromolar range. Structure activity relationship (SAR) of the 32 derivatives showed that N-benzylated compounds possess good activity than N-alkylated compounds. N-benzylated compounds 2ad and 2af were found very active with their IC 50 values toward AChE in submicromolar range (0.8µM and 0.6µM respectively). Binding modes of the synthesized compounds were explored by using GOLD (Genetic Optimization for Ligand Docking) suit v5.4.1. Computational predictions of ADMET studies reveal that all the compounds have good pharmacokinetic properties with no AMES toxicity and carcinogenicity. Moreover, all the compounds are predicted to be absorbed in human intestine and also have the ability to cross blood brain barrier. Overall, the synthesized compounds have established a structural foundation for the design of new inhibitors of cholinesterase. Copyright © 2017 Elsevier Inc. All rights reserved.

Is the EDRF in the cerebral circulation NO? Its release by shear and the dangers in interpreting the effects of NOS inhibitors.

PubMed

Rosenblum, W I

1998-09-01

Evidence from investigations of brain microcirculation (pial arterioles) reveals at least 3 different endothelium (EC) dependent mechanisms for dilation. Only one of the three can be triggered by acetylcholine (ACh) and in this vascular bed it is only this path that is dependent upon endothelial nitric oxide synthase (NOS) which produces nitric oxide (NO) from arginine. In this vascular bed the ACh sensitive path cannot be triggered by bradykinin (BK). This state of affairs appears to differ from that found in other beds or in endothelium cultured from conductance vessels. In the cerebral microcirculation there is considerable pharmacological evidence that the endothelium derived relaxing factor (EDRF) for ACh is not NO itself but may contain NO. In many experimental vascular settings the release of the NOS dependent EDRF is shear dependent. In the cerebral microcirculation there are several studies suggesting, in vivo, that this is correct. Among these are the following: (1) vessels narrow when shear is reduced after carotid ligation, and remain so along with unresponsiveness to ACh for at least ten minutes following resumption of flow. This may be important in developing stroke. The collapse is not passive due to low pressure. We know this because the narrowed vessels with their low intraluminal shear and pressure are still capable of large dilation by the NO donor, sodium nitropruside; (2) the antiplatelet effects of EC which are mediated, in part, by the EDRF for ACh are enhanced for 10 to 20 minutes following the transient increase and return of shear within these vessels. If the reverse is also true, reductions of shear may have important harmful proaggregant effects on platelets (and leukocytes) in the microvascular bed of developing infarcts. However most of the cited work depends upon pharmacological inhibitors of NOS to "prove" that NOS and an EDRF/NO are involved. In the last three years evidence in cats and rats shows that many of the NOS inhibitors

A mutation in the extracellular domain of the α7 nAChR reduces calcium permeability.

PubMed

Colón-Sáez, José O; Yakel, Jerrel L

2014-08-01

The α7 neuronal nicotinic acetylcholine receptor (nAChR) displays the highest calcium permeability among the different subtypes of nAChRs expressed in the mammalian brain and can impact cellular events including neurotransmitter release, second messenger cascades, cell survival, and apoptosis. The selectivity for cations in nAChRs is thought to be achieved in part by anionic residues which are located on either side of the channel mouth and increase relative cationic concentration. Mutagenesis studies have improved our understanding of the role of the second transmembrane domain and the intracellular loop of the channel in ion selectivity. However, little is known about the influence that the extracellular domain (ECD) plays in ion permeation. In the α7 nAChR, it has been found that the ECD contains a ring of ten aspartates (two per subunit) that is believed to face the lumen of the pore and could attract cations for permeation. Using mutagenesis and a combination of electrophysiology and imaging techniques, we tested the possible involvement of these aspartate residues in the calcium permeability of the rat α7 nAChR. We found that one of these residues (the aspartate at position 44) appears to be essential since mutating it to alanine resulted in a decrease in amplitude for both whole cell and single-channel responses and in the complete disappearance of detectable calcium changes in most cells, which indicates that the ECD of the α7 nAChR plays a key role in calcium permeation.

A mutation in the extracellular domain of the α7 nAChR reduces calcium permeability

PubMed Central

Colón-Sáez, José O.

2013-01-01

The α7 neuronal nicotinic acetylcholine receptor (nAChR) displays the highest calcium permeability among the different subtypes of nAChRs expressed in the mammalian brain and can impact cellular events including neurotransmitter release, second messenger cascades, cell survival, and apoptosis. The selectivity for cations in nAChRs is thought to be achieved in part by anionic residues which are located on either side of the channel mouth and increase relative cationic concentration. Mutagenesis studies have improved our understanding of the role of the second transmembrane domain and the intracellular loop of the channel in ion selectivity. However, little is known about the influence that the extracellular domain (ECD) plays in ion permeation. In the α7 nAChR, it has been found that the ECD contains a ring of ten aspartates (two per subunit) that is believed to face the lumen of the pore and could attract cations for permeation. Using mutagenesis and a combination of electrophysiology and imaging techniques, we tested the possible involvement of these aspartate residues in the calcium permeability of the rat α7 nAChR. We found that one of these residues (the aspartate at position 44) appears to be essential since mutating it to alanine resulted in a decrease in amplitude for both whole cell and single-channel responses and in the complete disappearance of detectable calcium changes in most cells, which indicates that the ECD of the α7 nAChR plays a key role in calcium permeation. PMID:24177919

Reciprocal activation of α5-nAChR and STAT3 in nicotine-induced human lung cancer cell proliferation.

PubMed

Zhang, Yao; Jia, Yanfei; Li, Ping; Li, Huanjie; Xiao, Dongjie; Wang, Yunshan; Ma, Xiaoli

2017-07-20

Cigarette smoking is the top environmental risk factor for lung cancer. Nicotine, the addictive component of cigarettes, induces lung cancer cell proliferation, invasion and migration via the activation of nicotinic acetylcholine receptors (nAChRs). Genome-wide association studies (GWAS) show that CHRNA5 gene encoding α5-nAChR is especially relevant to lung cancer. However, the mechanism of this subunit in lung cancer is not clear. In the present study, we demonstrate that the expression of α5-nAChR is correlated with phosphorylated STAT3 (pSTAT3) expression, smoking history and lower survival of non-small cell lung cancer (NSCLC) samples. Nicotine increased the levels of α5-nAChR mRNA and protein in NSCLC cell lines and activated the JAK2/STAT3 signaling cascade. Nicotine-induced activation of JAK2/STAT3 signaling was inhibited by the silencing of α5-nAChR. Characterization of the CHRNA5 promoter revealed four STAT3-response elements. ChIP assays confirmed that the CHRNA5 promoter contains STAT3 binding sites. By silencing STAT3 expression, nicotine-induced upregulation of α5-nAChR was suppressed. Downregulation of α5-nAChR and/or STAT3 expression inhibited nicotine-induced lung cancer cell proliferation. These results suggest that there is a feedback loop between α5-nAChR and STAT3 that contributes to the nicotine-induced tumor cell proliferation, which indicates that α5-nAChR is an important therapeutic target involved in tobacco-associated lung carcinogenesis. Copyright © 2017 Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and Genetics Society of China. Published by Elsevier Ltd. All rights reserved.

Patient autoantibodies deplete postsynaptic muscle-specific kinase leading to disassembly of the ACh receptor scaffold and myasthenia gravis in mice

PubMed Central

Cole, R N; Ghazanfari, N; Ngo, S T; Gervásio, O L; Reddel, S W; Phillips, W D

2010-01-01

The postsynaptic muscle-specific kinase (MuSK) coordinates formation of the neuromuscular junction (NMJ) during embryonic development. Here we have studied the effects of MuSK autoantibodies upon the NMJ in adult mice. Daily injections of IgG from four MuSK autoantibody-positive myasthenia gravis patients (MuSK IgG; 45 mg day−1i.p. for 14 days) caused reductions in postsynaptic ACh receptor (AChR) packing as assessed by fluorescence resonance energy transfer (FRET). IgG from the patients with the highest titres of MuSK autoantibodies caused large (51–73%) reductions in postsynaptic MuSK staining (cf. control mice; P < 0.01) and muscle weakness. Among mice injected for 14 days with control and MuSK patient IgGs, the residual level of MuSK correlated with the degree of impairment of postsynaptic AChR packing. However, the loss of postsynaptic MuSK preceded this impairment of postsynaptic AChR. When added to cultured C2 muscle cells the MuSK autoantibodies caused tyrosine phosphorylation of MuSK and the AChR β-subunit, and internalization of MuSK from the plasma membrane. The results suggest a pathogenic mechanism in which MuSK autoantibodies rapidly deplete MuSK from the postsynaptic membrane leading to progressive dispersal of postsynaptic AChRs. Moreover, maintenance of postsynaptic AChR packing at the adult NMJ would appear to depend upon physical engagement of MuSK with the AChR scaffold, notwithstanding activation of the MuSK-rapsyn system of AChR clustering. PMID:20603331

Gas Chromatography, GC/Mass Analysis and Bioactivity of Essential Oil from Aerial Parts of Ferulago trifida: Antimicrobial, Antioxidant, AChE Inhibitory, General Toxicity, MTT Assay and Larvicidal Activities.

PubMed

Tavakoli, Saeed; Vatandoost, Hassan; Zeidabadinezhad, Reza; Hajiaghaee, Reza; Hadjiakhoondi, Abbas; Abai, Mohammad Reza; Yassa, Narguess

2017-09-01

We aimed to investigate different biological properties of aerial parts essential oil of Ferulago trifida Boiss and larvicidal activity of its volatile oils from all parts of plant. Essential oil was prepared by steam distillation and analyzed by Gas chromatography and GC/Mass. Antioxidant, antimicrobial, cytotoxic effects and AChE inhibitory of the oil were investigated using DPPH, disk diffusion method, MTT assay and Ellman methods. Larvicidal activity of F. trifida essential oil against malaria vector Anopheles stephensi was carried out according to the method described by WHO. In GC and GC/MS analysis, 58 compounds were identified in the aerial parts essential oil, of which E-verbenol (9.66%), isobutyl acetate (25.73%) and E-β-caryophyllene (8.68%) were main compounds. The oil showed (IC 50 = 111.2μg/ml) in DPPH and IC 50 = 21.5 mg/ml in the investigation of AChE inhibitory. Furthermore, the oil demonstrated toxicity with (LD 50 = 1.1μg/ml) in brine shrimp lethality test and with (IC 50 = 22.0, 25.0 and 42.55 μg/ml) on three cancerous cell lines (MCF-7, A-549 and HT-29) respectively. LC 50 of stem, root, aerial parts, fruits, and flowers essential oils against larvae of An. stephensi were equal with 10.46, 22.27, 20.50, 31.93 and 79.87ppm respectively. In antimicrobial activities, essential oil was effective on all specimens except Escherichia coli , Aspergillus niger and Candida albicans. The essential oil showed moderate antioxidant activity, strong antimicrobial properties and good toxic effect in brine shrimp test and MTT assay on three cancerous cell lines.

Gas Chromatography, GC/Mass Analysis and Bioactivity of Essential Oil from Aerial Parts of Ferulago trifida: Antimicrobial, Antioxidant, AChE Inhibitory, General Toxicity, MTT Assay and Larvicidal Activities

PubMed Central

Tavakoli, Saeed; Vatandoost, Hassan; Zeidabadinezhad, Reza; Hajiaghaee, Reza; Hadjiakhoondi, Abbas; Abai, Mohammad Reza; Yassa, Narguess

2017-01-01

Background: We aimed to investigate different biological properties of aerial parts essential oil of Ferulago trifida Boiss and larvicidal activity of its volatile oils from all parts of plant. Methods: Essential oil was prepared by steam distillation and analyzed by Gas chromatography and GC/Mass. Antioxidant, antimicrobial, cytotoxic effects and AChE inhibitory of the oil were investigated using DPPH, disk diffusion method, MTT assay and Ellman methods. Larvicidal activity of F. trifida essential oil against malaria vector Anopheles stephensi was carried out according to the method described by WHO. Results: In GC and GC/MS analysis, 58 compounds were identified in the aerial parts essential oil, of which E-verbenol (9.66%), isobutyl acetate (25.73%) and E-β-caryophyllene (8.68%) were main compounds. The oil showed (IC50= 111.2μg/ml) in DPPH and IC50= 21.5 mg/ml in the investigation of AChE inhibitory. Furthermore, the oil demonstrated toxicity with (LD50= 1.1μg/ml) in brine shrimp lethality test and with (IC50= 22.0, 25.0 and 42.55 μg/ml) on three cancerous cell lines (MCF-7, A-549 and HT-29) respectively. LC50 of stem, root, aerial parts, fruits, and flowers essential oils against larvae of An. stephensi were equal with 10.46, 22.27, 20.50, 31.93 and 79.87ppm respectively. In antimicrobial activities, essential oil was effective on all specimens except Escherichia coli, Aspergillus niger and Candida albicans. Conclusion: The essential oil showed moderate antioxidant activity, strong antimicrobial properties and good toxic effect in brine shrimp test and MTT assay on three cancerous cell lines. PMID:29322058

Targeting cholinesterase inhibitor poisoning with a novel blocker against both nicotinic and muscarinic receptors.

PubMed

Luo, Wangqian; Ge, Xulin; Cui, Wenyu; Wang, Hai

2010-08-01

Clinicians have been treating poisoning by acetylcholinesterase inhibitors (ChEI) for more than half a century. However, the current atropine-centered therapy still cannot protect completely against all ChEIs, and poisoning by ChEIs is fatal in more than 20% of cases. Various solutions that try to enhance atropine's antimuscarinic effects have been used, but these fail to increase the antidotal effect, and their too potent muscarinic antagonism may produce incapacitating side effects. We hypothesized that, in the treatment of ChEI poisoning, the high death rate may not be attributed to the insufficient muscarinic antagonism but to the lack of nicotinic antagonism. To test this hypothesis, we designed and synthesized benthiactzine, a drug that blocks both muscarinic acetylcholine receptors (mAChRs) and nicotinic acetylcholine receptors (nAChRs). A specific [(3)H]quinuclidinyl benzilate-binding assay showed that benthiactzine was much weaker than atropine in binding to five different mAChR subtypes or to mAChRs expressed in 14 different tissues. Electrophysiological measures were used to identify and characterize benthiactzine's antinicotinic effect on three typical neuronal nAChRs subtypes, alpha4beta2, alpha4beta4, and alpha7, which are expressed heterogenously in SH-EP1 cells. Finally, benthiactzine afforded better protection than atropine against the most lethal ChEI, VX or sarin, in a mouse model. These results indicate that the antidotal effect may not be directly related to the antidote's antimuscarinic effect and that the antinicotinic effect may provide additional protection against ChEI poisoning. This new drug may benefit future antidote discovery.

Menthol Enhances Nicotine Reward-Related Behavior by Potentiating Nicotine-Induced Changes in nAChR Function, nAChR Upregulation, and DA Neuron Excitability.

PubMed

Henderson, Brandon J; Wall, Teagan R; Henley, Beverley M; Kim, Charlene H; McKinney, Sheri; Lester, Henry A

2017-11-01

Understanding why the quit rate among smokers of menthol cigarettes is lower than non-menthol smokers requires identifying the neurons that are altered by nicotine, menthol, and acetylcholine. Dopaminergic (DA) neurons in the ventral tegmental area (VTA) mediate the positive reinforcing effects of nicotine. Using mouse models, we show that menthol enhances nicotine-induced changes in nicotinic acetylcholine receptors (nAChRs) expressed on midbrain DA neurons. Menthol plus nicotine upregulates nAChR number and function on midbrain DA neurons more than nicotine alone. Menthol also enhances nicotine-induced changes in DA neuron excitability. In a conditioned place preference (CPP) assay, we observed that menthol plus nicotine produces greater reward-related behavior than nicotine alone. Our results connect changes in midbrain DA neurons to menthol-induced enhancements of nicotine reward-related behavior and may help explain how smokers of menthol cigarettes exhibit reduced cessation rates.

Menthol Enhances Nicotine Reward-Related Behavior by Potentiating Nicotine-Induced Changes in nAChR Function, nAChR Upregulation, and DA Neuron Excitability

PubMed Central

Henderson, Brandon J; Wall, Teagan R; Henley, Beverley M; Kim, Charlene H; McKinney, Sheri; Lester, Henry A

2017-01-01

Understanding why the quit rate among smokers of menthol cigarettes is lower than non-menthol smokers requires identifying the neurons that are altered by nicotine, menthol, and acetylcholine. Dopaminergic (DA) neurons in the ventral tegmental area (VTA) mediate the positive reinforcing effects of nicotine. Using mouse models, we show that menthol enhances nicotine-induced changes in nicotinic acetylcholine receptors (nAChRs) expressed on midbrain DA neurons. Menthol plus nicotine upregulates nAChR number and function on midbrain DA neurons more than nicotine alone. Menthol also enhances nicotine-induced changes in DA neuron excitability. In a conditioned place preference (CPP) assay, we observed that menthol plus nicotine produces greater reward-related behavior than nicotine alone. Our results connect changes in midbrain DA neurons to menthol-induced enhancements of nicotine reward-related behavior and may help explain how smokers of menthol cigarettes exhibit reduced cessation rates. PMID:28401925

ACh-induced endothelial NO synthase translocation, NO release and vasodilatation in the hamster microcirculation in vivo

PubMed Central

Figueroa, Xavier F; González, Daniel R; Martínez, Agustín D; Durán, Walter N; Boric, Mauricio P

2002-01-01

Studies in cultured cells show that activation of endothelial nitric oxide (NO) synthase (eNOS) requires the dissociation of this enzyme from its inhibitory association with caveolin-1 (Cav-1), and perhaps its translocation from plasma membrane caveolae to other cellular compartments. We investigated the hypothesis that in vivo NO-dependent vasodilatation is associated with the translocation of eNOS from the cell membrane. To this end, we applied ACh topically (10-100 μm for 10 min) to the hamster cheek pouch microcirculation and measured NO production, blood flow and vessel diameter, and assessed subcellular eNOS distribution by Western blotting. Baseline NO production was 54.4 ± 5.2 pmol min−1 (n = 16). ACh increased NO release, caused arteriolar and venular dilatation and elevated microvascular flow. These responses were inhibited by NG-nitro-L-arginine (30 μm). The maximal increase in NO production induced by 10 μm and 100 μm ACh was 45 ± 20 % and 111 ± 33 %, respectively; the corresponding blood flow increases were 50 ± 10 % and 130 ± 24 %, respectively (n = 4-6). Both responses followed a similar time course, although increases in NO preceded flow changes. In non-stimulated tissues, eNOS was distributed mainly in the microsomal fraction. ACh-induced vasodilatation was associated with eNOS translocation to the cytosolic and Golgi-enriched fractions. After 1.5, 3.0 or 6.0 min of application, 10 μm ACh decreased the level of membrane-bound eNOS by -13 ± 4 %, -60 ± 4 % and -19 ± 17 %, respectively; at the same time points, 100 μm ACh reduced microsomal eNOS content by -38 ± 9 %, -61 ± 16 % and -40 ± 18 %, respectively (n = 4-5). In all cases, microsomal Cav-1 content did not change. The close ACh concentration dependence and the concomitance between eNOS subcellular redistribution and NO release support the concept that eNOS translocation from the plasma membrane is part of an activation mechanism that induces NO-dependent vasodilatation in

Arsenic toxicity induced endothelial dysfunction and dementia: Pharmacological interdiction by histone deacetylase and inducible nitric oxide synthase inhibitors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharma, Bhupesh, E-mail: drbhupeshresearch@gmail.com; Sharma, P.M.

Arsenic toxicity has been reported to damage all the major organs including the brain and vasculature. Dementia including Alzheimer's disease (AD) and vascular dementia (VaD) are posing greater risk to the world population as it is now increasing at a faster rate. We have investigated the role of sodium butyrate, a selective histone deacetylase (HDAC) inhibitor and aminoguanidine, a selective inducible nitric oxide synthase (iNOS) inhibitor in pharmacological interdiction of arsenic toxicity induced vascular endothelial dysfunction and dementia in rats. Arsenic toxicity was done by administering arsenic drinking water to rats. Morris water-maze (MWM) test was used for assessment ofmore » learning and memory. Endothelial function was assessed using student physiograph. Oxidative stress (aortic superoxide anion, serum and brain thiobarbituric acid reactive species, brain glutathione) and nitric oxide levels (serum nitrite/nitrate) were also measured. Arsenic treated rats have shown impairment of endothelial function, learning and memory, reduction in serum nitrite/nitrate and brain GSH levels along with increase in serum and brain TBARS. Sodium butyrate as well as aminoguanidine significantly convalesce arsenic induced impairment of learning, memory, endothelial function, and alterations in various biochemical parameters. It may be concluded that arsenic induces endothelial dysfunction and dementia, whereas, sodium butyrate, a HDAC inhibitor as well as aminoguanidine, a selective iNOS inhibitor may be considered as potential agents for the management of arsenic induced endothelial dysfunction and dementia. - Highlights: • As has induced endothelial dysfunction (Edf) and vascular dementia (VaD). • As has increased oxidative stress, AChE activity and decreased serum NO. • Inhibitors of HDAC and iNOS have attenuated As induced Edf and VaD. • Both the inhibitors have attenuated As induced biochemical changes. • Inhibitor of HDAC and iNOS has shown good

Concomitant alpha7 and beta2 nicotinic AChR subunit deficiency leads to impaired energy homeostasis and increased physical activity in mice.

PubMed

Somm, Emmanuel; Guérardel, Audrey; Maouche, Kamel; Toulotte, Audrey; Veyrat-Durebex, Christelle; Rohner-Jeanrenaud, Françoise; Maskos, Uwe; Hüppi, Petra S; Schwitzgebel, Valérie M

2014-05-01

Nicotinic acetylcholine receptors (nAChRs) are pentameric ligand-gated cation channels well characterized in neuronal signal transmission. Moreover, recent studies have revealed nAChR expression in nonneuronal cell types throughout the body, including tissues involved in metabolism. In the present study, we screen gene expression of nAChR subunits in pancreatic islets and adipose tissues. Mice pancreatic islets present predominant expression of α7 and β2 nAChR subunits but at a lower level than in central structures. Characterization of glucose and energy homeostasis in α7β2nAChR(-/-) mice revealed no major defect in insulin secretion and sensitivity but decreased glycemia apparently unrelated to gluconeogenesis or glycogenolysis. α7β2nAChR(-/-) mice presented an increase in lean and bone body mass and a decrease in fat storage with normal body weight. These observations were associated with elevated spontaneous physical activity in α7β2nAChR(-/-) mice, mainly due to elevation in fine vertical (rearing) activity while their horizontal (ambulatory) activity remained unchanged. In contrast to α7nAChR(-/-) mice presenting glucose intolerance and insulin resistance associated to excessive inflammation of adipose tissue, the present metabolic phenotyping of α7β2nAChR(-/-) mice revealed a metabolic improvement possibly linked to the increase in spontaneous physical activity related to central β2nAChR deficiency. Copyright © 2014 Elsevier Inc. All rights reserved.

The human carbonic anhydrase isoenzymes I and II (hCA I and II) inhibition effects of trimethoxyindane derivatives.

PubMed

Taslimi, Parham; Gulcin, Ilhami; Ozgeris, Bunyamin; Goksu, Suleyman; Tumer, Ferhan; Alwasel, Saleh H; Supuran, Claudiu T

2016-01-01

Carbonic anhydrases (CAs, EC 4.2.1.1) had six genetically distinct families described to date in various organisms. There are 16 known CA isoforms in humans. Human CA isoenzymes I and II (hCA I and hCA II) are ubiquitous cytosolic isoforms. Acetylcholine esterase (AChE. EC 3.1.1.7) is a hydrolase that hydrolyzes the neurotransmitter acetylcholine relaying the signal from the nerve. In this study, some trimethoxyindane derivatives were investigated as inhibitors against the cytosolic hCA I and II isoenzymes, and AChE enzyme. Both hCA isozymes were inhibited by trimethoxyindane derivatives in the low nanomolar range. These compounds were good hCA I inhibitors (Kis in the range of 1.66-4.14 nM) and hCA II inhibitors (Kis of 1.37-3.12 nM) and perfect AChE inhibitors (Kis in the range of 1.87-7.53 nM) compared to acetazolamide as CA inhibitor (Ki: 6.76 nM for hCA I and Ki: 5.85 nM for hCA II) and Tacrine as AChE inhibitor (Ki: 7.64 nM).

PRN 88-2: Clustering of Quaternary Ammonium Compounds

EPA Pesticide Factsheets

This Notice announces that EPA has clustered the Quaternary Ammonium Compounds into four groups for the purpose of testing chemicals to build a database that will support continued registration of the entire family of quaternary ammonium compounds

The α7-nACh nicotinic receptor and its role in memory and selected diseases of the central nervous system.

PubMed

Baranowska, Urszula; Wiśniewska, Róża Julia

2017-07-30

α7-nACh is one of the major nicotinic cholinergic receptor subtypes found in the brain. It is broadly expressed in the hippocampal and cortical neurons, the regions which play a key role in memory formation. Although α7-nACh receptors may serve as postsynaptic receptors mediating classical neurotransmission, they usually function as presynaptic modulators responsible for the release of other neurotransmitters, such as glutamate, γ-aminobutyric acid, dopamine, and norepinephrine. They can, therefore, affect a wide array of neurobiological functions. In recent years, research has found that a large number of agonists and positive allosteric modulators of α7-nAChR induce beneficial effects on learning and memory. Consistently, mice deficient in chrna7 (the gene encoding α7-nAChR protein), are characterized by memory deficits. In addition, decreased expression and function of α7-nAChR is associated agoniwith many neurological diseases including schizophrenia, bipolar disorder, learning disability, attention deficit hyperactivity disorder, Alzheimer disease, autism, and epilepsy. In the recent years many animal experiments and clinical trials using α7-nAChR ligands were conducted. The results of these studies strongly indicate that agonists and positive allosteric modulators of α7-nAChR are promising therapeutic agents for diseases associated with cognitive deficits.

Molecular recognition of thiaclopride by Aplysia californica AChBP: new insights from a computational investigation

NASA Astrophysics Data System (ADS)

Alamiddine, Zakaria; Selvam, Balaji; Cerón-Carrasco, José P.; Mathé-Allainmat, Monique; Lebreton, Jacques; Thany, Steeve H.; Laurent, Adèle D.; Graton, Jérôme; Le Questel, Jean-Yves

2015-12-01

The binding of thiaclopride (THI), a neonicotinoid insecticide, with Aplysia californica acetylcholine binding protein ( Ac-AChBP), the surrogate of the extracellular domain of insects nicotinic acetylcholine receptors, has been studied with a QM/QM' hybrid methodology using the ONIOM approach (M06-2X/6-311G(d):PM6). The contributions of Ac-AChBP key residues for THI binding are accurately quantified from a structural and energetic point of view. The importance of water mediated hydrogen-bond (H-bond) interactions involving two water molecules and Tyr55 and Ser189 residues in the vicinity of the THI nitrile group, is specially highlighted. A larger stabilization energy is obtained with the THI- Ac-AChBP complex compared to imidacloprid (IMI), the forerunner of neonicotinoid insecticides. Pairwise interaction energy calculations rationalize this result with, in particular, a significantly more important contribution of the pivotal aromatic residues Trp147 and Tyr188 with THI through CH···π/CH···O and π-π stacking interactions, respectively. These trends are confirmed through a complementary non-covalent interaction (NCI) analysis of selected THI- Ac-AChBP amino acid pairs.

Modulatory effects of α7 nAChRs on the immune system and its relevance for CNS disorders.

PubMed

Kalkman, Hans O; Feuerbach, Dominik

2016-07-01

The clinical development of selective alpha-7 nicotinic acetylcholine receptor (α7 nAChR) agonists has hitherto been focused on disorders characterized by cognitive deficits (e.g., Alzheimer's disease, schizophrenia). However, α7 nAChRs are also widely expressed by cells of the immune system and by cells with a secondary role in pathogen defense. Activation of α7 nAChRs leads to an anti-inflammatory effect. Since sterile inflammation is a frequently observed phenomenon in both psychiatric disorders (e.g., schizophrenia, melancholic and bipolar depression) and neurological disorders (e.g., Alzheimer's disease, Parkinson's disease, and multiple sclerosis), α7 nAChR agonists might show beneficial effects in these central nervous system disorders. In the current review, we summarize information on receptor expression, the intracellular signaling pathways they modulate and reasons for receptor dysfunction. Information from tobacco smoking, vagus nerve stimulation, and cholinesterase inhibition is used to evaluate the therapeutic potential of selective α7 nAChR agonists in these inflammation-related disorders.

Immune responses to HTLV-I(ACH) during acute infection of pig-tailed macaques.

PubMed

McGinn, Therese M; Wei, Qing; Stallworth, Jackie; Fultz, Patricia N

2004-04-01

Human T cell lymphotropic virus type 1 (HTLV-I) is causally linked to adult T cell leukemia/lymphoma (ATL) and a chronic progressive neurological disease, HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). A nonhuman primate model that reproduces disease symptoms seen in HTLV-I-infected humans might facilitate identification of initial immune responses to the virus and an understanding of pathogenic mechanisms in HTLV-I-related disease. Previously, we showed that infection of pig-tailed macaques with HTLV-I(ACH) is associated with multiple signs of disease characteristic of both HAM/TSP and ATL. We report here that within the first few weeks after HTLV-I(ACH) infection of pig-tailed macaques, serum concentrations of interferon (IFN)-alpha increased and interleukin-12 decreased transiently, levels of nitric oxide were elevated, and activation of CD4(+) and CD8(+) lymphocytes and CD16(+) natural killer cells in peripheral blood were observed. HTLV-I(ACH) infection elicited virus-specific antibodies in all four animals within 4 to 6 weeks; however, Tax-specific lymphoproliferative responses were not detected until 25-29 weeks after infection in all four macaques. IFN-gamma production by peripheral blood cells stimulated with a Tax or Gag peptide was detected to varying degrees in all four animals by ELISPOT assay. Peripheral blood lymphocytes from one animal that developed only a marginal antigen-specific cellular response were unresponsive to mitogen stimulation during the last few weeks preceding its death from a rapidly progressive disease syndrome associated with HTLV-I(ACH) infection of pig-tailed macaques. The results show that during the first few months after HTLV-I(ACH) infection, activation of both innate and adaptive immunity, limited virus-specific cellular responses, sustained immune system activation, and, in some cases, immunodeficiency were evident. Thus, this animal model might be valuable for understanding early stages of infection

Comparative analyses of quaternary arrangements in homo-oligomeric proteins in superfamilies: Functional implications.

PubMed

Sudha, Govindarajan; Srinivasan, Narayanaswamy

2016-09-01

A comprehensive analysis of the quaternary features of distantly related homo-oligomeric proteins is the focus of the current study. This study has been performed at the levels of quaternary state, symmetry, and quaternary structure. Quaternary state and quaternary structure refers to the number of subunits and spatial arrangements of subunits, respectively. Using a large dataset of available 3D structures of biologically relevant assemblies, we show that only 53% of the distantly related homo-oligomeric proteins have the same quaternary state. Considering these homologous homo-oligomers with the same quaternary state, conservation of quaternary structures is observed only in 38% of the pairs. In 36% of the pairs of distantly related homo-oligomers with different quaternary states the larger assembly in a pair shows high structural similarity with the entire quaternary structure of the related protein with lower quaternary state and it is referred as "Russian doll effect." The differences in quaternary state and structure have been suggested to contribute to the functional diversity. Detailed investigations show that even though the gross functions of many distantly related homo-oligomers are the same, finer level differences in molecular functions are manifested by differences in quaternary states and structures. Comparison of structures of biological assemblies in distantly and closely related homo-oligomeric proteins throughout the study differentiates the effects of sequence divergence on the quaternary structures and function. Knowledge inferred from this study can provide insights for improved protein structure classification and function prediction of homo-oligomers. Proteins 2016; 84:1190-1202. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Atomic interactions of neonicotinoid agonists with AChBP: Molecular recognition of the distinctive electronegative pharmacophore

PubMed Central

Talley, Todd T.; Harel, Michal; Hibbs, Ryan E.; Radić, Zoran; Tomizawa, Motohiro; Casida, John E.; Taylor, Palmer

2008-01-01

Acetylcholine-binding proteins (AChBPs) from mollusks are suitable structural and functional surrogates of the nicotinic acetylcholine receptors when combined with transmembrane spans of the nicotinic receptor. These proteins assemble as a pentamer with identical ACh binding sites at the subunit interfaces and show ligand specificities resembling those of the nicotinic receptor for agonists and antagonists. A subset of ligands, termed the neonicotinoids, exhibit specificity for insect nicotinic receptors and selective toxicity as insecticides. AChBPs are of neither mammalian nor insect origin and exhibit a distinctive pattern of selectivity for the neonicotinoid ligands. We define here the binding orientation and determinants of differential molecular recognition for the neonicotinoids and classical nicotinoids by estimates of kinetic and equilibrium binding parameters and crystallographic analysis. Neonicotinoid complex formation is rapid and accompanied by quenching of the AChBP tryptophan fluorescence. Comparisons of the neonicotinoids imidacloprid and thiacloprid in the binding site from Aplysia californica AChBP at 2.48 and 1.94 Å in resolution reveal a single conformation of the bound ligands with four of the five sites occupied in the pentameric crystal structure. The neonicotinoid electronegative pharmacophore is nestled in an inverted direction compared with the nicotinoid cationic functionality at the subunit interfacial binding pocket. Characteristic of several agonists, loop C largely envelops the ligand, positioning aromatic side chains to interact optimally with conjugated and hydrophobic regions of the neonicotinoid. This template defines the association of interacting amino acids and their energetic contributions to the distinctive interactions of neonicotinoids. PMID:18477694

Design, synthesis and biological evaluation of phthalimide-alkylamine derivatives as balanced multifunctional cholinesterase and monoamine oxidase-B inhibitors for the treatment of Alzheimer's disease.

PubMed

Sang, Zhipei; Wang, Keren; Wang, Huifang; Yu, Lintao; Wang, Huijuan; Ma, Qianwen; Ye, Mengyao; Han, Xue; Liu, Wenmin

2017-11-15

A series of novel phthalimide-alkylamine derivatives were synthesized and evaluated as multi-functions inhibitors for the treatment of Alzheimer's disease (AD). The results showed that compound TM-9 could be regarded as a balanced multi-targets active molecule. It exhibited potent and balanced inhibitory activities against ChE and MAO-B (huAChE, huBuChE, and huMAO-B with IC 50 values of 1.2μM, 3.8μM and 2.6 μM, respectively) with low selectivity. Both kinetic analysis of AChE inhibition and molecular modeling study suggested that TM-9 binds simultaneously to the catalytic active site and peripheral anionic site of AChE. Interestingly, compound TM-9 abided by Lipinski's rule of five. Furthermore, our investigation proved that TM-9 indicated weak cytotoxicity, and it could cross the blood-brain barrier (BBB) in vitro. The results suggest that compound TM-9, an interesting multi-targeted active molecule, offers an attractive starting point for further lead optimization in the drug-discovery process against Alzheimer's disease. Copyright © 2017 Elsevier Ltd. All rights reserved.

Automated Docking with Protein Flexibility in the Design of Femtomolar “Click Chemistry” Inhibitors of Acetylcholinesterase

PubMed Central

Morris, Garrett M.; Green, Luke G.; Radić, Zoran; Taylor, Palmer; Sharpless, K. Barry; Olson, Arthur J.; Grynszpan, Flavio

2013-01-01

The use of computer-aided structure-based drug design prior to synthesis has proven to be generally valuable in suggesting improved binding analogues of existing ligands.1 Here we describe the application of the program AutoDock2 to the design of a focused library that was used in the “click chemistry in-situ” generation of the most potent non-covalent inhibitor of the enzyme acetylcholinesterase (AChE) yet developed (Kd = ~100 fM).3 AutoDock version 3.0.5 has been widely distributed and successfully used to predict bound conformations of flexible ligands. Here, we also used a version of AutoDock which permits additional conformational flexibility in selected amino acid sidechains of the target protein. PMID:23451944

Molecular Targets for Organophosphates in the Central Nervous System

DTIC Science & Technology

2006-04-01

above and cholinesterase activity was measured in the supernatants after 0, 15, 30 and 60 min= exposure to PB (100 nM). Drugs and biological...a quaternary carbamate that does not cross the blood brain barrier (BBB) appreciably and inhibits reversibly AChE and BuChE with similar potencies... activity could be maintained by ACh released from cholinergic neurons in our culture. In the continuous presence of atropine, exposure of the neurons to

Rat nicotinic ACh receptor α7 and β2 subunits co-assemble to form functional heteromeric nicotinic receptor channels

PubMed Central

Khiroug, Serguei S; Harkness, Patricia C; Lamb, Patricia W; Sudweeks, Sterling N; Khiroug, Leonard; Millar, Neil S; Yakel, Jerrel L

2002-01-01

Rat hippocampal interneurons express diverse subtypes of functional nicotinic acetylcholine receptors (nAChRs), including α7-containing receptors that have properties unlike those expected for homomeric α7 nAChRs. We previously reported a strong correlation between expression of the α7 and of the β2 subunits in individual neurons. To explore whether co-assembly of the α7 and β2 subunits might occur, these subunits were co-expressed in Xenopus oocytes and the functional properties of heterologously expressed nAChRs were characterized by two-electrode voltage clamp. Co-expression of the β2 subunit, both wild-type and mutant forms, with the α7 subunit significantly slowed the rate of nAChR desensitization and altered the pharmacological properties. Whereas ACh, carbachol and choline were full or near-full agonists for homomeric α7 receptor channels, both carbachol and choline were only partial agonists in oocytes expressing both α7 and β2 subunits. In addition the EC50 values for all three agonists significantly increased when the β2 subunit was co-expressed with the α7 subunit. Co-expression with the β2 subunit did not result in any significant change in the current-voltage curve. Biochemical evidence for the co-assembly of the α7 and β2 subunits was obtained by co-immunoprecipitation of these subunits from transiently transfected human embryonic kidney (TSA201) cells. These data provide direct biophysical and molecular evidence that the nAChR α7 and β2 subunits co-assemble to form a functional heteromeric nAChR with functional and pharmacological properties different from those of homomeric α7 channels. This co-assembly may help to explain nAChR channel diversity in rat hippocampal interneurons, and perhaps in other areas of the nervous system. PMID:11956333

Memantine Inhibits α3β2-nAChRs-Mediated Nitrergic Neurogenic Vasodilation in Porcine Basilar Arteries

PubMed Central

Wu, Celeste Yin-Chieh; Chen, Po-Yi; Chen, Mei-Fang; Kuo, Jon-Son; Lee, Tony Jer-Fu

2012-01-01

Memantine, an NMDA receptor antagonist used for treatment of Alzheimer’s disease (AD), is known to block the nicotinic acetylcholine receptors (nAChRs) in the central nervous system (CNS). In the present study, we examined by wire myography if memantine inhibited α3β2-nAChRs located on cerebral perivascular sympathetic nerve terminals originating in the superior cervical ganglion (SCG), thus, leading to inhibition of nicotine-induced nitrergic neurogenic dilation of isolated porcine basilar arteries. Memantine concentration-dependently blocked nicotine-induced neurogenic dilation of endothelium-denuded basilar arteries without affecting that induced by transmural nerve stimulation, sodium nitroprusside, or isoproterenol. Furthermore, memantine significantly inhibited nicotine-elicited inward currents in Xenopous oocytes expressing α3β2-, α7- or α4β2-nAChR, and nicotine-induced calcium influx in cultured rat SCG neurons. These results suggest that memantine is a non-specific antagonist for nAChR. By directly inhibiting α3β2-nAChRs located on the sympathetic nerve terminals, memantine blocks nicotine-induced neurogenic vasodilation of the porcine basilar arteries. This effect of memantine is expected to reduce the blood supply to the brain stem and possibly other brain regions, thus, decreasing its clinical efficacy in the treatment of Alzheimer’s disease. PMID:22792283

Synthesis, in vitro and in vivo studies, and molecular modeling of N-alkylated dextromethorphan derivatives as non-competitive inhibitors of α3β4 nicotinic acetylcholine receptor.

PubMed

Jozwiak, Krzysztof; Targowska-Duda, Katarzyna M; Kaczor, Agnieszka A; Kozak, Joanna; Ligeza, Agnieszka; Szacon, Elzbieta; Wrobel, Tomasz M; Budzynska, Barbara; Biala, Grazyna; Fornal, Emilia; Poso, Antti; Wainer, Irving W; Matosiuk, Dariusz

2014-12-15

9 N-alkylated derivatives of dextromethorphan are synthesized and studied as non-competitive inhibitors of α3β4 nicotinic acetylcholine receptors (nAChRs). In vitro activity towards α3β4 nicotinic acetylcholine receptor is determined using a patch-clamp technique and is in the micromolar range. Homology modeling, molecular docking and molecular dynamics of ligand-receptor complexes in POPC membrane are used to find the mode of interactions of N-alkylated dextromethorphan derivatives with α3β4 nAChR. The compounds, similarly as dextromethorphan, interact with the middle portion of α3β4 nAChR ion channel. Finally, behavioral tests confirmed potential application of the studied compounds for the treatment of addiction. Copyright © 2014 Elsevier Ltd. All rights reserved.

In situ analysis of corrosion inhibitors using a portable mass spectrometer with paper spray ionization.

PubMed

Jjunju, Fred P M; Li, Anyin; Badu-Tawiah, Abraham; Wei, Pu; Li, Linfan; Ouyang, Zheng; Roqan, Iman S; Cooks, R Graham

2013-07-07

Paper spray (PS) ambient ionization is implemented using a portable mass spectrometer and applied to the detection of alkyl quaternary ammonium salts in a complex oil matrix. These salts are commonly used as active components in the formulation of corrosion inhibitors. They were identified in oil and confirmed by their fragmentation patterns recorded using tandem mass spectrometry (MS/MS). The cations of alkyl and benzyl-substituted quaternary ammonium salts showed characteristic neutral losses of CnH2n (n carbon number of the longest chain) and C7H8, respectively. Individual quaternary ammonium compounds were detected at low concentrations (<1 ng μL(-1)) and over a dynamic range of ∼5 pg μL(-1) to 500 pg μL(-1) (ppb). Direct detection of these compounds in complex oil samples without prior sample preparation or pre-concentration was also demonstrated using a home-built miniature mass spectrometer at levels below 1 ng μL(-1).

Spacetime Non-Commutativity Corrections to the Cardy-Verlinde Formula of Achúcarro-Ortiz Black Hole

NASA Astrophysics Data System (ADS)

Setare, M. R.

2007-02-01

In this letter we compute the corrections to the Cardy-Verlinde formula of Achúcarro-Ortiz black hole, which is the most general two-dimensional black hole derived from the three-dimensional rotating Banados-Teitelboim-Zanelli black hole. These corrections stem from the space non-commutativity. We show that in non-commutative case, non-rotating Achúcarro-Ortiz black hole in contrast with commutative case has two horizons.

Conjugates of γ-Carbolines and Phenothiazine as new selective inhibitors of butyrylcholinesterase and blockers of NMDA receptors for Alzheimer Disease.

PubMed

Makhaeva, Galina F; Lushchekina, Sofya V; Boltneva, Natalia P; Sokolov, Vladimir B; Grigoriev, Vladimir V; Serebryakova, Olga G; Vikhareva, Ekaterina A; Aksinenko, Alexey Yu; Barreto, George E; Aliev, Gjumrakch; Bachurin, Sergey O

2015-08-18

Alzheimer disease is a multifactorial pathology and the development of new multitarget neuroprotective drugs is promising and attractive. We synthesized a group of original compounds, which combine in one molecule γ-carboline fragment of dimebon and phenothiazine core of methylene blue (MB) linked by 1-oxo- and 2-hydroxypropylene spacers. Inhibitory activity of the conjugates toward acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and structurally close to them carboxylesterase (CaE), as well their binding to NMDA-receptors were evaluated in vitro and in silico. These newly synthesized compounds showed significantly higher inhibitory activity toward BChE with IC50 values in submicromolar and micromolar range and exhibited selective inhibitory action against BChE over AChE and CaE. Kinetic studies for the 9 most active compounds indicated that majority of them were mixed-type BChE inhibitors. The main specific protein-ligand interaction is π-π stacking of phenothiazine ring with indole group of Trp82. These compounds emerge as promising safe multitarget ligands for the further development of a therapeutic approach against aging-related neurodegenerative disorders such as Alzheimer and/or other pathological conditions.

Enhancement of Attentional Performance by Selective Stimulation of α4β2* nAChRs: Underlying Cholinergic Mechanisms

PubMed Central

Howe, William M; Ji, Jinzhao; Parikh, Vinay; Williams, Sarah; Mocaër, Elisabeth; Trocmé-Thibierge, Caryn; Sarter, Martin

2010-01-01

Impairments in attention are a major component of the cognitive symptoms of neuropsychiatric and neurodegenerative disorders. Using an operant sustained attention task (SAT), including a distractor condition (dSAT), we assessed the putative pro-attentional effects of the selective α4β2* nicotinic acetylcholine receptor (nAChR) agonist S 38232 in comparison with the non-selective agonist nicotine. Neither drug benefited SAT performance. However, in interaction with the increased task demands implemented by distractor presentation, the selective agonist, but not nicotine, enhanced the detection of signals during the post-distractor recovery period. This effect is consistent with the hypothesis that second-long increases in cholinergic activity (‘transients') mediate the detection of cues and that nAChR agonists augment such transients. Electrochemical recordings of prefrontal cholinergic transients evoked by S 38232 and nicotine indicated that the α4β2* nAChR agonist evoked cholinergic transients that were characterized by a faster rise time and more rapid decay than those evoked by nicotine. Blockade of the α7 nAChR ‘sharpens' nicotine-evoked transients; therefore, we determined the effects of co-administration of nicotine and the α7 nAChR antagonist methyllycaconitine on dSAT performance. Compared with vehicle and nicotine alone, this combined treatment significantly enhanced the detection of signals. These results indicate that compared with nicotine, α4β2* nAChR agonists significantly enhance attentional performance and that the dSAT represents a useful behavioral screening tool. The combined behavioral and electrochemical evidence supports the hypothesis that nAChR agonist-evoked cholinergic transients, which are characterized by rapid rise time and fast decay, predict robust drug-induced enhancement of attentional performance. PMID:20147893

Design, synthesis, pharmacological evaluation, QSAR analysis, molecular modeling and ADMET of novel donepezil-indolyl hybrids as multipotent cholinesterase/monoamine oxidase inhibitors for the potential treatment of Alzheimer's disease.

PubMed

Bautista-Aguilera, Oscar M; Esteban, Gerard; Bolea, Irene; Nikolic, Katarina; Agbaba, Danica; Moraleda, Ignacio; Iriepa, Isabel; Samadi, Abdelouahid; Soriano, Elena; Unzeta, Mercedes; Marco-Contelles, José

2014-03-21

The design, synthesis, and pharmacological evaluation of donepezil-indolyl based amines 7-10, amides 12-16, and carboxylic acid derivatives 5 and 11, as multipotent ASS234 analogs, able to inhibit simultaneously cholinesterase (ChE) and monoamine oxidase (MAO) enzymes for the potential treatment of Alzheimer's disease (AD), is reported. Theoretical studies using 3D-Quantitative Structure-Activity Relationship (3D-QSAR) was used to define 3D-pharmacophores for inhibition of MAO A/B, AChE, and BuChE enzymes. We found that, in general, and for the same substituent, amines are more potent ChE inhibitors (see compounds 12, 13 versus 7 and 8) or equipotent (see compounds 14, 15 versus 9 and 10) than the corresponding amides, showing a clear EeAChE inhibition selectivity. For the MAO inhibition, amides were not active, and among the amines, compound 14 was totally MAO A selective, while amines 15 and 16 were quite MAO A selective. Carboxylic acid derivatives 5 and 11 showed a multipotent moderate selective profile as EeACE and MAO A inhibitors. Propargylamine 15 [N-((5-(3-(1-benzylpiperidin-4-yl)propoxy)-1-methyl-1H-indol-2-yl)methyl)prop-2-yn-1-amine] resulted in the most potent hMAO A (IC50 = 5.5 ± 1.4 nM) and moderately potent hMAO B (IC50 = 150 ± 31 nM), EeAChE (IC50 = 190 ± 10 nM), and eqBuChE (IC50 = 830 ± 160 nM) inhibitor. However, the analogous N-allyl and the N-morpholine derivatives 16 and 14 deserve also attention as they show an attractive multipotent profile. To sum up, donepezil-indolyl hybrid 15 is a promising drug for further development for the potential prevention and treatment of AD. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Going up in Smoke? A Review of nAChRs-based Treatment Strategies for Improving Cognition in Schizophrenia

PubMed Central

Boggs, Douglas L.; Carlson, Jon; Cortes-Briones, Jose; Krystal, John H.; D’Souza, D. Cyril

2015-01-01

Cognitive impairment is known to be a core deficit in schizophrenia. Existing treatments for schizophrenia have limited efficacy against cognitive impairment. The ubiquitous use of nicotine in this population is thought to reflect an attempt by patients to self-medicate certain symptoms associated with the illness. Concurrently there is evidence that nicotinic receptors that have lower affinity for nicotine are more important in cognition. Therefore, a number of medications that target nicotinic acetylcholine receptors (nAChRs) have been tested or are in development. In this article we summarize the clinical evidence of nAChRs dysfunction in schizophrenia and review clinical studies testing either nicotine or nicotinic medications for the treatment of cognitive impairment in schizophrenia. Some evidence suggests beneficial effects of nAChRs based treatments for the attentional deficits associated with schizophrenia. Standardized cognitive test batteries have failed to capture consistent improvements from drugs acting at nAChRs. However, more proximal measures of brain function, such as ERPs relevant to information processing impairments in schizophrenia, have shown some benefit. Further work is necessary to conclude that nAChRs based treatments are of clinical utility in the treatment of cognitive deficits of schizophrenia. PMID:24345265

A novel route to recognizing quaternary ammonium cations using electrospray mass spectrometry.

PubMed

Shackman, Holly M; Ding, Wei; Bolgar, Mark S

2015-01-01

Characterizing and elucidating structures is a commonplace and necessary activity in the pharmaceutical industry with mass spectrometry and NMR being the primary tools for analysis. Although many functional groups are readily identifiable, quaternary ammonium cations have proven to be difficult to unequivocally identify using these techniques. Due to the lack of an N-H bond, quaternary ammonium groups can only be detected in the (1)H NMR spectra by weak signals generated from long-range (14)N-H coupling, which by themselves are inconclusive evidence of a quaternary ammonium functional group. Due to their low intensity, these signals are frequently not detected. Additionally, ions cannot be differentiated in a mass spectrum as an M(+) or [M + H](+) ion without prior knowledge of the compound's structure. In order to utilize mass spectrometry as a tool for determining this functionality, ion cluster formation of quaternary ammonium cations and non-quaternary amines was studied using electrospray ionization. Several mobile phase modifiers were compared; however, the addition of small amounts of trifluoroacetic acid proved superior in producing characteristic and intense [M +2TFA](-) clusters for compounds containing quaternary ammonium cations when using negative electrospray. By fragmenting this characteristic ion using CID, nearly all compounds studied could be unambiguously identified as containing a quaternary ammonium cation or a non-quaternary amine attributable to the presence (non-quaternary amine) or absence (quaternary ammonium cation) of the resulting [2TFA + H](-) ion in the product spectra. This method of analysis provides a rapid, novel, and reliable technique for indicating the presence of quaternary ammonium cations in order to aid in structural elucidation.

Nicotine-Induced Effects on Nicotinic Acetylcholine Receptors (nAChRs), Ca2+ and Brain-Derived Neurotrophic Factor (BDNF) in STC-1 Cells.

PubMed

Qian, Jie; Mummalaneni, Shobha K; Alkahtani, Reem M; Mahavadi, Sunila; Murthy, Karnam S; Grider, John R; Lyall, Vijay

2016-01-01

In addition to the T2R bitter taste receptors, neuronal nicotinic acetylcholine receptors (nAChRs) have recently been shown to be involved in the bitter taste transduction of nicotine, acetylcholine and ethanol. However, at present it is not clear if nAChRs are expressed in enteroendocrine cells other than beta cells of the pancreas and enterochromaffin cells, and if they play a role in the synthesis and release of neurohumoral peptides. Accordingly, we investigated the expression and functional role of nAChRs in enteroendocrine STC-1 cells. Our studies using RT-PCR, qRT-PCR, immunohistochemical and Western blotting techniques demonstrate that STC-1 cells express several α and β nAChR subunits. Exposing STC-1 cells to nicotine acutely (24h) or chronically (4 days) induced a differential increase in the expression of nAChR subunit mRNA and protein in a dose- and time-dependent fashion. Mecamylamine, a non-selective antagonist of nAChRs, inhibited the nicotine-induced increase in mRNA expression of nAChRs. Exposing STC-1 cells to nicotine increased intracellular Ca2+ in a dose-dependent manner that was inhibited in the presence of mecamylamine or dihydro-β-erythroidine, a α4β2 nAChR antagonist. Brain-derived neurotrophic factor (BDNF) mRNA and protein were detected in STC-1 cells using RT-PCR, specific BDNF antibody, and enzyme-linked immunosorbent assay. Acute nicotine exposure (30 min) decreased the cellular content of BDNF in STC-1 cells. The nicotine-induced decrease in BDNF was inhibited in the presence of mecamylamine. We also detected α3 and β4 mRNA in intestinal mucosal cells and α3 protein expression in intestinal enteroendocrine cells. We conclude that STC-1 cells and intestinal enteroendocrine cells express nAChRs. In STC-1 cells nAChR expression is modulated by exposure to nicotine in a dose- and time-dependent manner. Nicotine interacts with nAChRs and inhibits BDNF expression in STC-1 cells.

Quaternary Geologic Map of Connecticut and Long Island Sound Basin

USGS Publications Warehouse

Stone, Janet Radway; Schafer, John P.; London, Elizabeth Haley; DiGiacomo-Cohen, Mary L.; Lewis, Ralph S.; Thompson, Woodrow B.

2005-01-01

The Quaternary geologic map (sheet 1) and explanatory figures and cross sections (sheet 2) portray the geologic features formed in Connecticut during the Quaternary Period, which includes the Pleistocene (glacial) and Holocene (postglacial) Epochs. The Quaternary Period has been a time of development of many details of the landscape and of all the surficial deposits. At least twice in the late Pleistocene, continental ice sheets swept across Connecticut. Their effects are of pervasive importance to the present occupants of the land. The Quaternary geologic map illustrates the geologic history and the distribution of depositional environments during the emplacement of glacial and postglacial surficial deposits and the landforms resulting from those events.

Inhibitory effects of psychotropic drugs on the acetylcholine receptor-operated potassium current (IK.ACh) in guinea-pig atrial myocytes.

PubMed

Okada, Muneyoshi; Watanabe, Shinya; Matada, Takashi; Asao, Yoko; Hamatani, Ramu; Yamawaki, Hideyuki; Hara, Yukio

2013-01-01

Influences of psychotropic drugs, six antipsychotics and three antidepressants, on acetylcholine receptor-operated potassium current (IK.ACh) were examined by a whole-cell patch clamp method in freshly isolated guinea-pig atrial myocyte. IK.ACh was induced by a superfusion of carbachol (CCh) or by an intracellular application of guanosine 5'-[thio] triphosphate (GTPγS). To elucidate mechanism for anticholinergic action, IC50 ratio, the ratio of IC50 for GTPγS-activated IK.ACh to CCh-induced IK.ACh, was calculated. Antipsychotics and antidepressants inhibited CCh-induced IK.ACh in a concentration-dependent manner. The IC50 values were as follows; chlorpromazine 0.53 μM, clozapine 0.06 μM, fluphenazine 2.69 μM, haloperidol 2.66 μM, sulpiride 42.3 μM, thioridazine 0.07 μM, amitriptyline 0.03 μM, imipramine 0.22 μM and maprotiline 1.81 μM. The drugs, except for sulpiride, inhibited GTPγS-activated IK.ACh with following IC50 values; chlorpromazine 1.71 μM, clozapine 14.9 μM, fluphenazine 3.55 μM, haloperidol 2.73 μM, thioridazine 1.90 μM, amitriptyline 7.55 μM, imipramine 7.09 μM and maprotiline 5.93 μM. The IC50 ratio for fluphenazine and haloperidol was close to unity. The IC50 ratio for chlorpromazine, clozapine, thioridazine, amitriptyline, imipramine and maprotiline was much higher than unity. The present findings suggest that the psychotropics studied suppress IK.ACh. Chlorpromazine, clozapine, thioridazine, amitriptyline, imipramine, maprotiline and sulpiride are preferentially acting on muscarinic receptor. Fluphenazine and haloperidol may act on G protein and/or potassium channel.

Antimicrobial Polymeric Materials with Quaternary Ammonium and Phosphonium Salts

PubMed Central

Xue, Yan; Xiao, Huining; Zhang, Yi

2015-01-01

Polymeric materials containing quaternary ammonium and/or phosphonium salts have been extensively studied and applied to a variety of antimicrobial-relevant areas. With various architectures, polymeric quaternary ammonium/phosphonium salts were prepared using different approaches, exhibiting different antimicrobial activities and potential applications. This review focuses on the state of the art of antimicrobial polymers with quaternary ammonium/phosphonium salts. In particular, it discusses the structure and synthesis method, mechanisms of antimicrobial action, and the comparison of antimicrobial performance between these two kinds of polymers. PMID:25667977

Design, synthesis and evaluation of novel cinnamic acid derivatives bearing N-benzyl pyridinium moiety as multifunctional cholinesterase inhibitors for Alzheimer's disease.

PubMed

Lan, Jin-Shuai; Hou, Jian-Wei; Liu, Yun; Ding, Yue; Zhang, Yong; Li, Ling; Zhang, Tong

2017-12-01

A novel family of cinnamic acid derivatives has been developed to be multifunctional cholinesterase inhibitors against AD by fusing N-benzyl pyridinium moiety and different substituted cinnamic acids. In vitro studies showed that most compounds were endowed with a noteworthy ability to inhibit cholinesterase, self-induced Aβ (1-42) aggregation, and to chelate metal ions. Especially, compound 5l showed potent cholinesterase inhibitory activity (IC 50 , 12.1 nM for eeAChE, 8.6 nM for hAChE, 2.6 μM for eqBuChE and 4.4 μM for hBuChE) and the highest selectivity toward AChE over BuChE. It also showed good inhibition of Aβ (1-42) aggregation (64.7% at 20 μM) and good neuroprotection on PC12 cells against amyloid-induced cell toxicity. Finally, compound 5l could penetrate the BBB, as forecasted by the PAMPA-BBB assay and proved in OF1 mice by ex vivo experiments. Overall, compound 5l seems to be a promising lead compound for the treatment of Alzheimer's diseases.

Extensive Quaternary glaciations in eastern Turkey

NASA Astrophysics Data System (ADS)

Yeşilyurt, Serdar; Akçar, Naki; Doǧan, Uǧur; Yavuz, Vural; Ivy-Ochs, Susan; Vockenhuber, Christof; Schlunegger, Fritz; Schlüchter, Christian

2016-04-01

During cold periods in the Quaternary, global ice volume increased and as a result valley glaciers advanced and the vice versa occurred during the warm periods. Quaternary glacier fluctuations had been also recorded in the Turkish mountains. Recently, the chronology of Late Quaternary advances in the northern and western Turkish mountains was reconstructed by surface exposure dating. However, these advances in the eastern Turkey are not dated yet. In this study, we investigated paleoglaciations in Kavuşşahap Mountains, which is located to the south of Lake Van in eastern Turkey. These mountains are one of the extensively glaciated areas in Turkey. Glacial activity is evidenced by more than 20 U-shaped valleys. For instance, one of the prominent and well-preserved glacial landscapes of Turkey is situated in the Narlıca valley system. Lateral and terminal moraines in the valley system indicate more than 10 glacial advances. To build their chronology, 39 erratic carbonaceous boulders were sampled for surface exposure dating with cosmogenic 36Cl. We also reconstructed the ice margin reconstruction of the Narlıca paleoglacier using the accumulation area ratio and area-altitude balance ratio approaches. We estimated an equilibrium line altitude (ELA) of ca. 2900 m above sea level based on the maximum ice extend, which implied ca. 800 m decrease in the ELA during the Late Quaternary in comparison to the lower bound of the modern ELA estimate. The first results of the surface exposure dating will be presented.

Synthesis and evaluation of 7-substituted coumarin derivatives as multimodal monoamine oxidase-B and cholinesterase inhibitors for the treatment of Alzheimer's disease.

PubMed

Joubert, Jacques; Foka, Germaine B; Repsold, Benjamin P; Oliver, Douglas W; Kapp, Erika; Malan, Sarel F

2017-01-05

A series of 7-substituted coumarin derivatives were designed and synthesised to display ChE and MAO-B inhibitory activity. The compounds consisted out of a coumarin structure (MAO-B inhibitor) and benzyl-, piperidine-, N-benzylpiperidine- or p-bromo-N-benzylpiperizine moiety, resembling the N-benzylpiperidine function of donepezil (ChE inhibitor), connected via an alkyl ether linkage at the 7 position. The biological assay results indicated that all the compounds (1-25) displayed selective inhibition to hMAO-B over hMAO-A, with the benzyloxy series (1-8, 10-13) showing nano-molar hMAO-B inhibition (IC 50 : 0.5-73 nM). Limited ChE inhibitory activity was however observed for the benzyloxy series with the exception of 2 and especially 3 showing selective BuChE inhibition. From this series 3 showed the best multifunctional activity (eqBuChE IC 50  = 0.96 μM, hMAO-A IC 50  = 2.13 μM, hMAO-B IC 50  = 0.0021 μM). Within the N-benzylpiperidine (16-19) and p-bromo-N-benzylpiperizine (21-24) series the compounds in general showed moderate ChE and MAO-B inhibitory activity. Of these compounds 19 was the most potent multifunctional agent showing good eeAChE and eqBuChE inhibition (IC 50  = 9.10 μM and 5.90 μM, respectively), and relatively potent and selective hMAO-B inhibition (IC 50  = 0.30 μM, SI = >33). Molecular modeling revealed that 19 was able to bind simultaneously to the CAS, mid-gorge and PAS sites of AChE and BuChE suggesting that it will be able to inhibit AChE induced Aβ aggregation. From this study, compounds that 3 and 19 can be considered as promising multifunctional lead compounds. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Concomitant use of acetylcholine esterase inhibitors and urinary antispasmodics among Finnish community-dwelling persons with Alzheimer disease.

PubMed

Torvinen-Kiiskinen, Sanna; Taipale, Heidi; Tanskanen, Antti; Tiihonen, Jari; Hartikainen, Sirpa

2014-12-01

Concomitant use of acetylcholine esterase inhibitors (AChEIs) and anticholinergic drugs, such as urinary antispasmodics (UA), is generally considered as inappropriate because of their opposite pharmacological actions. However, prevalence and the duration or factors associated with concomitant use have not been previously studied among community-dwelling persons with Alzheimer disease (AD). The aim of this study was to examine the prevalence and duration of concomitant use of AChEIs and UAs among community-dwelling persons with AD and factors associated with concomitant use. Register-based data of the MEDALZ-2005 Study included all community-dwelling persons with clinically diagnosed AD at the end of year 2005 in Finland. Persons using AChEI drugs during the 4-year follow-up (2006-2009) were included in the present study (n = 20,442). Among AChEI users, 1576 persons used UA during the follow-up. Prevalence of concomitant use of AChEIs and UAs was 7.3% (n = 1491) during the 4-year follow-up. The median duration of concomitant use was 236 days. Factors associated with concomitant use were age younger than 80 years (odds ratio [OR], 1.20; 95% confidence interval [CI], 1.08-1.34), male sex (OR, 1.16; 95% CI, 1.04-1.30), Parkinson disease (OR, 1.98; 95% CI, 1.55-2.52), diabetes (OR, 1.25; 95% CI, 1.08-1.45), and prostatic cancer (OR, 1.54; 95% CI, 1.13-2.09). Despite their antagonizing action, concomitant use of AChEIs and UAs was quite common among Finnish community-dwelling persons with AD. In addition, duration of concomitant use was comparatively long. It is recommended to consider some other options than UAs to treat urinary incontinence among persons with AD.

Auger electron spectroscopy, secondary ion mass spectroscopy and optical characterization of a-C-H and BN films

NASA Technical Reports Server (NTRS)

Pouch, J. J.; Alterovitz, S. A.; Warner, J. D.

1986-01-01

The amorphous dielectrics a-C:H and BN were deposited on III-V semiconductors. Optical band gaps as high as 3 eV were measured for a-C:H generated by C4H10 plasmas; a comparison was made with bad gaps obtained from films prepared by CH4 glow discharges. The ion beam deposited BN films exhibited amorphous behavior with band gaps on the order of 5 eV. Film compositions were studied by Auger electron spectroscopy (AES), x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). The optical properties were characterized by ellipsometry, UV/VIS absorption, and IR reflection and transmission. Etching rates of a-C:H subjected to O2 dicharges were determined.

Modulators of Acetylcholinesterase Activity: From Alzheimer's Disease to Anti-Cancer Drugs.

PubMed

Lazarevic-Pasti, Tamara; Leskovac, Andreja; Momic, Tatjana; Petrovic, Sandra; Vasic, Vesna

2017-01-01

Acetylcholinesterase (AChE) is involved in the termination of impulse transmission by rapid hydrolysis of the neurotransmitter acetylcholine in numerous cholinergic pathways in the central and peripheral nervous systems. The enzyme inactivation leads to acetylcholine accumulation, hyperstimulation of nicotinic and muscarinic receptors, and disrupted neurotransmission. Hence, acetylcholinesterase inhibitors, interacting with the enzyme as their primary target, are applied as relevant drugs for different neurodegenerative diseases (such as Alzheimer's and Parkinson's) as well as toxins. At the same time, there are increasing evidence that in non-neuronal context, AChE is involved in the regulation of cell proliferation, differentiation, apoptosis and cell-cell interaction. An irregular expression of AChE has been found in different types of tumors, suggesting the involvement of AChE in the regulation of tumor development. Having all this in mind, there is a possibility that some AChE inhibitors could be used as anti-cancer agents. This contribution will discuss a broad range of possible application of different AChE inhibitors as drugs, from well-known anti-Alzheimer's disease drugs to their use in cancer treatment in future. Emphasis will be put on various known AChE inhibitors classes, whose application as drugs could be controversy, as well as on newly investigated natural products, which can also modulate AChE activity. It is not clear a patient treated for neurodegenerative condition prone to increased risk for some types of cancer and vice versa. This is necessary to keep in mind during rational drug design process for all therapies, which are based on AChE as a target molecule. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Understanding the molecular mechanism of aryl acylamidase activity of acetylcholinesterase - An in silico study.

PubMed

Chinnadurai, Raj Kumar; Saravanaraman, Ponne; Boopathy, Rathanam

2015-08-15

Acetylcholinesterase (AChE) exhibits two different activities, namely esterase and aryl acylamidase (AAA). Unlike esterase, AAA activity of AChE is inhibited by the active site inhibitors while remaining unaffected by the peripheral anionic site inhibitors. This differential inhibitory pattern of active and peripheral anionic site inhibitors on the AAA activity remains unanswered. To answer this, we investigated the mechanism of binding and trafficking of AAA substrates using in silico tools. Molecular docking of serotonin and AAA substrates (o-nitroacetanilide, and o-nitrotrifluoroacetanilide,) onto AChE shows that these compounds bind at the side door of AChE. Thus, we conceived that the AAA substrates prefer the side door to reach the active site for their catalysis. Further, steered molecular dynamics simulations show that the force required for binding and trafficking of the AAA substrate through the side door is comparatively lesser than their dissociation (900kJ/mol/nm). Among the two substrates, o-nitrotrifluoroacetanilide required lesser force (380kJ/mol/nm) than o-nitroacetanilide the (550kJ/mol/nm) for its binding, thus validating o-nitrotrifluoroacetanilide as a better substrate. With these observations, we resolve that the AAA activity of AChE is mediated through its side door. Therefore, binding of PAS inhibitors at the main door of AChE remain ineffective against AAA activity. Copyright © 2015 Elsevier Inc. All rights reserved.

Synthesis and anticoagulant activity of the quaternary ammonium chitosan sulfates.

PubMed

Fan, Lihong; Wu, Penghui; Zhang, Jinrong; Gao, Song; Wang, Libo; Li, Mingjia; Sha, Mingming; Xie, Weiguo; Nie, Min

2012-01-01

Quaternary ammonium chitosan sulfates with diverse degrees of substitution (DS) ascribed to sulfate groups between 0.52 and 1.55 were synthesized by reacting quaternary ammonium chitosan with an uncommon sulfating agent (N(SO(3)Na)(3)) that was prepared from sodium bisulfite (NaHSO(3)) through reaction with sodium nitrite (NaNO(2)) in the aqueous system homogeneous. The structures of the derivatives were characterized by FTIR, (1)H NMR and (13)C NMR. The factors affecting DS of quaternary ammonium chitosan sulfates which included the molar ratio of NaNO(2) to quaternary ammonium chitosan, sulfated temperature, sulfated time and pH of sulfated reaction solution were investigated in detail. Its anticoagulation activity in vitro was determined by an activated partial thromboplastin time (APTT) assay, a thrombin time (TT) assay and a prothrombin time (PT) assay. Results of anticoagulation assays showed quaternary ammonium chitosan sulfates significantly prolonged APTT and TT, but not PT, and demonstrated that the introduction of sulfate groups into the quaternary ammonium chitosan structure improved its anticoagulant activity obviously. The study showed its anticoagulant properties strongly depended on its DS, concentration and molecular weight. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

Comparison of zofenopril and lisinopril to study the role of the sulfhydryl-group in improvement of endothelial dysfunction with ACE-inhibitors in experimental heart failure

PubMed Central

Buikema, H; Monnink, S H J; Tio, R A; Crijns, H J G M; de Zeeuw, D; van Gilst, W H

2000-01-01

We evaluated the role of SH-groups in improvement of endothelial dysfunction with ACE-inhibitors in experimental heart failure. To this end, we compared the vasoprotective effect of chronic treatment with zofenopril (plus SH-group) versus lisinopril (no SH-group), or N-acetylcysteine (only SH-group) in myocardial infarcted (MI) heart failure rats.After 11 weeks of treatment, aortas were obtained and studied as ring preparations for endothelium-dependent and -independent dilatation in continuous presence of indomethacin to avoid interference of vasoactive prostanoids, and the selective presence of the NOS-inhibitor L-NMMA to determine NO-contribution.Total dilatation after receptor-dependent stimulation with acetylcholine (ACh) was attenuated (−49%, P<0.05) in untreated MI (n=11), compared to control rats with no-MI (n=8). This was in part due to impaired NO-contribution in MI (−50%, P<0.05 versus no-MI). At the same time the capacity for generation of biologically active NO after receptor-independent stimulation with A23187 remained intact.Chronic treatment with n-acetylcysteine (n=8) selectively restored NO-contribution in total dilatation to ACh. In contrast, both ACE-inhibitors fully normalized total dilatation to ACh, including the part mediated by NO (no significant differences between zofenopril (n=10) and lisinopril (n=8)).Zofenopril, but not lisinopril, additionally potentiated the effect of endogenous NO after A23187-induced release from the endothelium (+100%) as well as that of exogenous NO provided by nitroglycerin (+22%) and sodium nitrite (+36%) (for all P<0.05 versus no-MI).We conclude that ACE-inhibition with a SH-group has a potential advantage in improvement of endothelial dysfunction through increased activity of NO after release from the endothelium into the vessel wall. Furthermore, this is the first study demonstrating the selective normalizing effect of N-actylcysteine on NO-contribution to ACh-induced dilatation in experimental heart

Biallelic mutation of UNC50, encoding a protein involved in AChR trafficking, is responsible for arthrogryposis.

PubMed

Abiusi, Emanuela; D'Alessandro, Manuela; Dieterich, Klaus; Quevarec, Loic; Turczynski, Sandrina; Valfort, Aurore-Cecile; Mezin, Paulette; Jouk, Pierre Simon; Gut, Marta; Gut, Ivo; Bessereau, Jean Louis; Melki, Judith

2017-10-15

Arthrogryposis multiplex congenita (AMC) is a developmental condition characterized by multiple joint contractures resulting from reduced or absent fetal movements. Homozygosity mapping of disease loci combined with whole exome sequencing in a consanguineous family presenting with lethal AMC allowed the identification of a homozygous frameshift deletion in UNC50 gene (c.750_751del:p.Cys251Phefs*4) in the index case. To assess the effect of the mutation, an equivalent mutation in the Caenorhabditis elegans orthologous gene was created using CRISPR/Cas9. We demonstrated that unc-50(kr331) modification caused the loss of acetylcholine receptor (AChR) expression in C. elegans muscle. unc-50(kr331) animals were as resistant to the cholinergic agonist levamisole as unc-50 null mutants suggesting that AChRs were no longer expressed in this animal model. This was confirmed by using a knock-in strain in which a red fluorescent protein was inserted into the AChR locus: no signal was detected in unc-50(kr331) background, suggesting that UNC-50, a protein known to be involved in AChR trafficking, was no longer functional. These data indicate that biallelic mutation in the UNC50 gene underlies AMC through a probable loss of AChR expression at the neuromuscular junction which is essential for the cholinergic transmission during human muscle development. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Cholinesterase inhibitors from the roots of Harpagophytum procumbens.

PubMed

Bae, Yoon Ho; Cuong, To Dao; Hung, Tran Manh; Kim, Jeong Ah; Woo, Mi Hee; Byeon, Jeong Su; Choi, Jae Sue; Min, Byung Sun

2014-01-01

Inhibition of cholinesterase has been proposed to be a therapeutic target for the treatment of Alzheimer's diseases. In our preliminary screening study on the acetylcholinesterase (AChE) inhibitory activity, an ethyl acetate soluble fraction of the roots of Harpagophytum procumbens (Pedaliaceae) was found to inhibit AChE activity at the concentration of 100 μg/mL. Ten compounds (1-10) were isolated from the active fraction and evaluated for their inhibitory effect on AChE and butyrylcholinesterase (BChE). Among the isolates, verbascosides (5, 6, and 8) containing a caffeoyl and a 3,4-dihydroxyphenethyl groups in their structures, showed effective AChE inhibitory activity and also possessed BChE inhibitory activity. The findings suggest that verbascoside derivatives may be partially related to the anti-Alzheimer effect of this medicinal plant.

Discovery of Highly Selective and Nanomolar Carbamate-Based Butyrylcholinesterase Inhibitors by Rational Investigation into Their Inhibition Mode.

PubMed

Sawatzky, Edgar; Wehle, Sarah; Kling, Beata; Wendrich, Jan; Bringmann, Gerhard; Sotriffer, Christoph A; Heilmann, Jörg; Decker, Michael

2016-03-10

Butyrylcholinesterase (BChE) is a promising target for the treatment of later stage cognitive decline in Alzheimer's disease. A set of pseudo-irreversible BChE inhibitors with high selectivity over hAChE was synthesized based on carbamates attached to tetrahydroquinazoline scaffolds with the 2-thiophenyl compound 2p as the most potent inhibitor of eqBChE (KC = 14.3 nM) and also of hBChE (KC = 19.7 nM). The inhibitors transfer the carbamate moiety onto the active site under release of the phenolic tetrahydroquinazoline scaffolds that themselves act as neuroprotectants. By combination of kinetic data with molecular docking studies, a plausible binding model was probed describing how the tetrahydroquinazoline scaffold guides the carbamate into a close position to the active site. The model explains the influence of the carrier scaffold onto the affinity of an inhibitor just before carbamate transfer. This strategy can be used to utilize the binding mode of other carbamate-based inhibitors.

The Ache: Genocide Continues in Paraguay. IWGIA Document No. 17.

ERIC Educational Resources Information Center

Munzel, Mark

In 1972, the Paraguayan Roman Catholic Church protested against the massacre of Indians in Paraguay. This was followed by further protests from Paraguayan intellectuals. These protests led to the removal of Jesus de Pereira, one of the executors of the official Ache policy. Thus, the critics were appeased. Since the beginning of 1973, new protests…

Acetylcholinesterase inhibitor treatment alleviated cognitive impairment caused by delayed encephalopathy due to carbon monoxide poisoning: Two case reports and a review of the literature.

PubMed

Yanagiha, Kumi; Ishii, Kazuhiro; Tamaoka, Akira

2017-02-01

Delayed encephalopathy due to carbon monoxide (CO) poisoning can even occur in patients with mild symptoms of acute CO poisoning. Some cases taking conventional hyperbaric oxygen (HBO) therapy or steroid-pulse therapy may be insufficient, and AchEI may be effective. We report two cases of delayed encephalopathy after acute CO poisoning involving two women aged 69 (Case 1) and 60 years (Case 2) whose cognitive function improved with acetylcholinesterase inhibitor (AchEI) treatment. Delayed encephalopathy occurred 25 and 35 days after acute CO poisoning in Case 1 and Case 2, respectively. Both patients demonstrated cognitive impairment, apathy, and hypokinesia on admission. Although hyperbaric oxygen therapy did not yield any significant improvements, cognitive dysfunction improved substantially. This was evidenced by an improved Mini-Mental State Examination score ffom 9 to 28 points in Case 1 and an improved Hasegawa's dementia rating scale score from 4 to 25 points in Case 2 after administration of an AchEI. In Case 1, we administered galantamine hydrobromide, which was related with improved white matter lesions initially detected on brain magnetic resonance imaging. However, in Case 2 white matter lesions persisted despite AchEI treatment. AchEI treatment may result in improved cognitive and frontal lobe function by increasing low acetylcholine concentrations in the hippocampus and frontal lobe caused by decreased nicotinic acetylcholine receptor levels in delayed encephalopathy after CO poisoning. Physicians should consider AchEIs for patients demonstrating delayed encephalopathy due to CO poisoning.

Bactericidal Specificity and Resistance Profile of Poly(Quaternary Ammonium) Polymers and Protein-Poly(Quaternary Ammonium) Conjugates.

PubMed

Ji, Weihang; Koepsel, Richard R; Murata, Hironobu; Zadan, Sawyer; Campbell, Alan S; Russell, Alan J

2017-08-14

Antibacterial polymers are potentially powerful biocides that can destroy bacteria on contact. Debate in the literature has surrounded the mechanism of action of polymeric biocides and the propensity for bacteria to develop resistance to them. There has been particular interest in whether surfaces with covalently coupled polymeric biocides have the same mechanism of action and resistance profile as similar soluble polymeric biocides. We designed and synthesized a series of poly(quaternary ammonium) polymers, with tailorable molecular structures and architectures, to engineer their antibacterial specificity and their ability to delay the development of bacterial resistance. These linear poly(quaternary ammonium) homopolymers and block copolymers, generated using atom transfer radical polymerization, had structure-dependent antibacterial specificity toward Gram positive and negative bacterial species. When single block copolymers contained two polymer segments of differing antibacterial specificity, the polymer combined the specificities of its two components. Nanoparticulate human serum albumin-poly(quaternary ammonium) conjugates of these same polymers, synthesized via "grafting from" atom transfer radical polymerization, were strongly biocidal and also exhibited a marked decrease in the rate of bacterial resistance development relative to linear polymers. These protein-biocide conjugates mimicked the behavior of surface-presented polycationic biocides rather than their nonproteinaceous counterparts.

α7 Nicotinic Acetylcholine Receptor (α7nAChR) Expression in Bone Marrow–Derived Non–T Cells Is Required for the Inflammatory Reflex

PubMed Central

Olofsson, Peder S; Katz, David A; Rosas-Ballina, Mauricio; Levine, Yaakov A; Ochani, Mahendar; Valdés-Ferrer, Sergio I; Pavlov, Valentin A; Tracey, Kevin J; Chavan, Sangeeta S

2012-01-01

The immune response to infection or injury coordinates host defense and tissue repair, but also has the capacity to damage host tissues. Recent advances in understanding protective mechanisms have found neural circuits that suppress release of damaging cytokines. Stimulation of the vagus nerve protects from excessive cytokine production and ameliorates experimental inflammatory disease. This mechanism, the inflammatory reflex, requires the α7 nicotinic acetylcholine receptor (α7nAChR), a ligand-gated ion channel expressed on macrophages, lymphocytes, neurons and other cells. To investigate cell-specific function of α7nAChR in the inflammatory reflex, we created chimeric mice by cross-transferring bone marrow between wild-type (WT) and α7nAChR-deficient mice. Deficiency of α7nAChR in bone marrow–derived cells significantly impaired vagus nerve–mediated regulation of tumor necrosis factor (TNF), whereas α7nAChR deficiency in neurons and other cells had no significant effect. In agreement with recent work, the inflammatory reflex was not functional in nude mice, because functional T cells are required for the integrity of the pathway. To investigate the role of T-cell α7nAChR, we adoptively transferred α7nAChR-deficient or WT T cells to nude mice. Transfer of WT and α7nAChR-deficient T cells restored function, indicating that α7nAChR expression on T cells is not necessary for this pathway. Together, these results indicate that α7nAChR expression in bone marrow–derived non–T cells is required for the integrity of the inflammatory reflex. PMID:22183893

Synthesis, kinetic studies and molecular modeling of novel tacrine dimers as cholinesterase inhibitors.

PubMed

de Aquino, Roney Anderson Nascimento; Modolo, Luzia Valentina; Alves, Rosemeire Brondi; de Fátima, Ângelo

2013-12-28

This study presents the synthesis of 15 new tacrine dimers as well as the Ki and IC50 results, studies of the kinetic mechanism, and molecular docking analysis of the dimers in relation to the cholinesterases hAChE, hBChE, EeAChE and eqBChE. In addition to spectroscopic characterization, X-ray structure determination was performed for two of the new compounds. These new dimers were found to be mixed nanomolar inhibitors of the evaluated targets with a broad and significant selectivity profile, and these properties are dependent on both the type of the linker and the volume of the hydroacridine alicyclic ring. The results indicate that the aromatic linkers play a significant role in generating specific interactions with the half-gorge region of the catalytic center. Thus, these types of linkers can positively modulate the electronic properties of the tacrine dimers studied with an improvement of their cholinesterase inhibition activity.

A positive allosteric modulator of α7 nAChRs augments neuroprotective effects of endogenous nicotinic agonists in cerebral ischaemia

PubMed Central

Kalappa, Bopanna I; Sun, Fen; Johnson, Stephen R; Jin, Kunlin; Uteshev, Victor V

2013-01-01

Background and Purpose Activation of α7 nicotinic acetylcholine receptors (nAChRs) can be neuroprotective. However, endogenous choline and ACh have not been regarded as potent neuroprotective agents because physiological levels of choline/ACh do not produce neuroprotective levels of α7 activation. This limitation may be overcome by the use of type-II positive allosteric modulators (PAMs-II) of α7 nAChRs, such as 1-(5-chloro-2,4-dimethoxyphenyl)-3-(5-methylisoxazol-3-yl)-urea (PNU-120596). This proof-of-concept study presents a novel neuroprotective paradigm that converts endogenous choline/ACh into potent neuroprotective agents in cerebral ischaemia by inhibiting α7 nAChR desensitization using PNU-120596. Experimental Approach An electrophysiological ex vivo cell injury assay (to quantify the susceptibility of hippocampal neurons to acute injury by complete oxygen and glucose deprivation; COGD) and an in vivo middle cerebral artery occlusion model of ischaemia were used in rats. Key Results Choline (20–200 μM) in the presence, but not absence of 1 μM PNU-120596 significantly delayed anoxic depolarization/injury of hippocampal CA1 pyramidal neurons, but not CA1 stratum radiatum interneurons, subjected to COGD in acute hippocampal slices and these effects were blocked by 20 nM methyllycaconitine, a selective α7 antagonist, thus, activation of α7 nAChRs was required. PNU-120596 alone was ineffective ex vivo. In in vivo experiments, both pre- and post-ischaemia treatments with PNU-120596 (30 mg·kg−1, s.c. and 1 mg·kg−1, i.v., respectively) significantly reduced the cortical/subcortical infarct volume caused by transient focal cerebral ischaemia. PNU-120596 (1 mg·kg−1, i.v., 30 min post-ischaemia) remained neuroprotective in rats subjected to a choline-deficient diet for 14 days prior to experiments. Conclusions and Implications PNU-120596 and possibly other PAMs-II significantly improved neuronal survival in cerebral ischaemia by augmenting

A mid-infrared flow-through sensor for label-free monitoring of enzyme inhibition.

PubMed

Armenta, S; Tomischko, W; Lendl, B

2008-12-01

Label-free monitoring of acetylcholinesterase (AChE) activity was achieved with a mid-infrared flow-through sensor. The flow-through sensor comprised agarose beads, carrying covalently immobilized AChE, which were placed in a temperature-controlled (37 degrees C) CaF(2) flow cell with an optical path of 60 mum. The sensor was incorporated into a computer-controlled sequential injection (SI) system for automated liquid handling. Different mixtures of enzyme substrate acetylcholine (ACh) and inhibitor (tacrine) were prepared and fed into the flow-through sensor. The flow was stopped as soon as the prepared mixtures reached the sensor. Enzymatic hydrolysis of ACh by AChE was directly monitored as it took place in the flow-through sensor. The inhibition effect of tacrine was calculated from the reaction-induced spectral changes, revealing an important decrease in the activity of AChE, approaching zero when the inhibitor concentration is high enough. The developed mid-infrared flow-through sensor is flexible and can be used to study the inhibitor activity of different target molecules as well as different enzymes.

Cognitive enhancing effect of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers on learning and memory

PubMed Central

Nade, V. S.; Kawale, L. A.; Valte, K. D.; Shendye, N. V.

2015-01-01

Objective: The present study was designed to investigate cognitive enhancing property of angiotensin-converting enzymes inhibitors (ACEI) and angiotensin receptor blockers (ARBs) in rats. Materials and Methods: The elevated plus maze (EPM), passive avoidance test (PAT), and water maze test (WMT) were used to assess cognitive enhancing activity in young and aged rats. Ramipril (10 mg/kg, p.o.), perindopril (10 mg/kg, i.p), losartan (20 mg/kg, i.p), and valsartan (20 mg/kg, p.o) were administered to assess their effect on learning and memory. Scopolamine (1 mg/kg, i.p) was used to impair cognitive function. Piracetam (200 mg/kg, i.p) was used as reference drug. Results: All the treatments significantly attenuated amnesia induced by aging and scopolamine. In EPM, aged and scopolamine-treated rats showed an increase in transfer latency (TL) whereas, ACEI and ARBs showed a significant decrease in TL. Treatment with ACEI and ARBs significantly increased step down latencies and decreased latency to reach the platform in target quadrant in young, aged and scopolamine-treated animals in PAT and WMT, respectively. The treatments inhibited acetylcholinesterase (AChE) enzyme in the brain. Similarly, all the treatments attenuated scopolamine-induced lipid peroxidation and normalize antioxidant enzymes. Conclusion: The results suggest that the cognitive enhancing effect of ACEI and ARBs may be due to inhibition of AChE or by regulation of antioxidant system or increase in formation of angiotensin IV. PMID:26069362

Why is quaternary prevention important in prevention?

PubMed Central

Tesser, Charles Dalcanale

2017-01-01

ABSTRACT Quaternary prevention consists in the identification of persons at risk of excessive medicalization and their protection against new unnecessary interventions, avoiding iatrogenic damages. Here, we argue about the importance of quaternary prevention in specific primary and secondary prevention. The recent great development of preventive medicine, biomedicalization of risks and their treatment as if they were diseases, and the powerful influence of the commercial interests of pharmaceutical industries on the production of medical-sanitary knowledge alter classifications, create diseases and pre-diseases, lower cutoff points, and erase the distinction between prevention and healing. This situation converts larger amounts of asymptomatic persons into sick individuals and diverts clinical attention and resources from sick persons to the healthy, from older adults to young persons, and from the poor to the rich. Quaternary prevention facilitates and induces the development and systematization of operational knowledge and guidelines to contain hypermedicalization and the damages of preventive actions in professional care, especially in primary health care. PMID:29211199

RgIA4 Potently Blocks Mouse α9α10 nAChRs and Provides Long Lasting Protection against Oxaliplatin-Induced Cold Allodynia.

PubMed

Christensen, Sean B; Hone, Arik J; Roux, Isabelle; Kniazeff, Julie; Pin, Jean-Philippe; Upert, Grégory; Servent, Denis; Glowatzki, Elisabeth; McIntosh, J Michael

2017-01-01

Transcripts for α9 and α10 nicotinic acetylcholine receptor (nAChR) subunits are found in diverse tissues. The function of α9α10 nAChRs is best known in mechanosensory cochlear hair cells, but elsewhere their roles are less well-understood. α9α10 nAChRs have been implicated as analgesic targets and α-conotoxins that block α9α10 nAChRs produce analgesia. However, some of these peptides show large potency differences between species. Additionally several studies have indicated that these conotoxins may also activate GABA B receptors (GABA B Rs). To further address these issues, we cloned the cDNAs of mouse α9 and α10 nAChR subunits. When heterologously expressed in Xenopus oocytes, the resulting α9α10 nAChRs had the expected pharmacology of being activated by acetylcholine and choline but not by nicotine. A conotoxin analog, RgIA4, potently, and selectively blocked mouse α9α10 nAChRs with low nanomolar affinity indicating that RgIA4 may be effectively used to study murine α9α10 nAChR function. Previous reports indicated that RgIA4 attenuates chemotherapy-induced cold allodynia. Here we demonstrate that RgIA4 analgesic effects following oxaliplatin treatment are sustained for 21 days after last RgIA4 administration indicating that RgIA4 may provide enduring protection against nerve damage. RgIA4 lacks activity at GABA B receptors; a bioluminescence resonance energy transfer assay was used to demonstrate that two other analgesic α-conotoxins, Vc1.1 and AuIB, also do not activate GABA B Rs expressed in HEK cells. Together these findings further support the targeting of α9α10 nAChRs in the treatment of pain.

Classification of protein quaternary structure by functional domain composition

PubMed Central

Yu, Xiaojing; Wang, Chuan; Li, Yixue

2006-01-01

Background The number and the arrangement of subunits that form a protein are referred to as quaternary structure. Quaternary structure is an important protein attribute that is closely related to its function. Proteins with quaternary structure are called oligomeric proteins. Oligomeric proteins are involved in various biological processes, such as metabolism, signal transduction, and chromosome replication. Thus, it is highly desirable to develop some computational methods to automatically classify the quaternary structure of proteins from their sequences. Results To explore this problem, we adopted an approach based on the functional domain composition of proteins. Every protein was represented by a vector calculated from the domains in the PFAM database. The nearest neighbor algorithm (NNA) was used for classifying the quaternary structure of proteins from this information. The jackknife cross-validation test was performed on the non-redundant protein dataset in which the sequence identity was less than 25%. The overall success rate obtained is 75.17%. Additionally, to demonstrate the effectiveness of this method, we predicted the proteins in an independent dataset and achieved an overall success rate of 84.11% Conclusion Compared with the amino acid composition method and Blast, the results indicate that the domain composition approach may be a more effective and promising high-throughput method in dealing with this complicated problem in bioinformatics. PMID:16584572

Midwifery students attribute different quantitative meanings to hurt, ache and pain: a cross-sectional survey.

PubMed

Bergh, Ingrid H E; Ek, Kristina; Mårtensson, Lena B

2013-06-01

Assessment of women's labor pain is seldom acknowledged in clinical practice or research. The words "aching" and "hurting" are frequently used by women to describe childbirth pain. The aim of this study was to determine the quantitative meanings midwifery students attribute to the terms "hurt", "ache" and "pain". Data was collected by self-administered questionnaire from students at seven Swedish midwifery programs. A total of 230 filled out and returned a completed questionnaire requesting them to rate, on a visual analog scale, the intensity of "hurt", "ache" or "pain" in the back, as reported by a fictitious parturient. The midwifery students attributed, with substantial individual variation, different quantitative meanings to the studied pain descriptors. To be able to communicate about pain with a woman in labor, it is essential that the midwife be familiar with the value of different words and what they mean to her as this may affect her assessment when the woman describes her pain. Copyright © 2012 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

Use of a novel radiometric method to assess the inhibitory effect of donepezil on acetylcholinesterase activity in minimally diluted tissue samples

PubMed Central

Kikuchi, Tatsuya; Okamura, Toshimitsu; Arai, Takuya; Obata, Takayuki; Fukushi, Kiyoshi; Irie, Toshiaki; Shiraishi, Tetsuya

2010-01-01

Background and purpose: Cholinesterase inhibitors have been widely used for the treatment of patients with dementia. Monitoring of the cholinesterase activity in the blood is used as an indicator of the effect of the cholinesterase inhibitors in the brain. The selective measurement of cholinesterase with low tissue dilution is preferred for accurate monitoring; however, the methods have not been established. Here, we investigated the effect of tissue dilution on the action of cholinesterase inhibitors using a novel radiometric method with selective substrates, N-[14C]methylpiperidin-4-yl acetate ([14C]MP4A) and (R)-N-[14C]methylpiperidin-3-yl butyrate ([14C]MP3B_R), for AChE and butyrylcholinesterase (BChE) respectively. Experimental approach: We investigated the kinetics of hydrolysis of [14C]-MP4A and [14C]-MP3B_R by cholinesterases, and evaluated the selectivity of [14C]MP4A and [14C]MP3B_R for human AChE and BChE, respectively, compared with traditional substrates. Then, IC50 values of cholinesterase inhibitors in minimally diluted and highly diluted tissues were measured with [14C]MP4A and [14C]MP3B_R. Key results: AChE and BChE activities were selectively measured as the first-order hydrolysis rates of [14C]-MP4A and [14C]MP3B_R respectively. The AChE selectivity of [14C]MP4A was an order of magnitude higher than traditional substrates used for the AChE assay. The IC50 values of specific AChE and BChE inhibitors, donepezil and ethopropazine, in 1.2-fold diluted human whole blood were much higher than those in 120-fold diluted blood. In addition, the IC50 values of donepezil in monkey brain were dramatically decreased as the tissue was diluted. Conclusions and implications: This method would effectively monitor the activity of cholinesterase inhibitors used for therapeutics, pesticides and chemical warfare agents. PMID:20401964

[Effect of acetylcholine and acetylcholinesterase on the activity of contractile vacuole of Amoeba proteus].

PubMed

Bagrov, Ia Iu; Manusova, N B

2011-01-01

Acetylcholine (ACh, 1 microM) stimulates activity of the contractile vacuole of proteus. The effect of ACh is not mimicked by its analogs which are not hydrolyzed by acetylcholinesterase (AChE), i. e., carbacholine and 5-methylfurmethide. The effect of ACh is not sensitive to the blocking action of M-cholinolytics, atropine and mytolone, but is suppressed by N-cholinolytic, tubocurarine. The inhibitors of AChE, eserine (0.01 microM) and armine (0.1 microM), suppress the effect of ACh on amoeba contractile vacuole. ACh does not affect activation of contractile vacuole induced by arginine-vasopressin (1 microM), but it blocks such effect of opiate receptors agonist, dynorphin A1-13 (0.01 microM). This effect of ACh is also suppressed by the inhibitors of AChE. These results suggest that, in the above-described effects of ACh, AChE acts not as an antagonist, but rather as a synergist.

Cholinesterases inhibition and molecular modeling studies of piperidyl-thienyl and 2-pyrazoline derivatives of chalcones.

PubMed

Shah, Muhammad Shakil; Khan, Shafi Ullah; Ejaz, Syeda Abida; Afridi, Saifullah; Rizvi, Syed Umar Farooq; Najam-Ul-Haq, Muhammad; Iqbal, Jamshed

2017-01-22

Super-activation of cholinesterases (acetylcholinesterase and butyrylcholinesterase) are linked to various neurological problems most precisely Alzheimer's disease (AD), which leads to senile dementia. Therefore, cholinesterases (AChE & BChE) inhibition are considered as a promising strategy for the treatment of Alzheimer's disease. FDA approved drugs for the treatment of AD, belong to a group of cholinesterase inhibitors. However, none of them is able to combat or completely abrogate the disease progression. Herein, we report a series of newly synthesized chalcone derivatives with anti-AD potential. For this purpose, a series of piperidyl-thienyl and 2-pyrazoline derivatives of chalcones were tested for their cholinesterases (AChE & BChE) inhibitory activity. All compounds were found as selective inhibitor of AChE. In piperidyl chalcones derivatives compound 1e having IC 50 of 0.16 ± 0.008 μM and 2m in 2-pyrazoline chalcones with IC 50 of 0.13 ± 0.006 μM, were found to be the most potent inhibitors of AChE, exhibiting ≈142 and ≈ 173-fold greater inhibitory potential compared to the reference inhibitor i.e., Neostigmine (IC 50  ± SEM = 22.2 ± 3.2 μM). Molecular docking studies of most potent inhibitors were carried out to investigate the binding interactions inside the active site. Molecular docking study revealed that potent compounds and co-crystalized ligand had same binding orientation within the active site of target enzyme. Most of these compounds are selective inhibitors of AChE with a potential use against progressive neurodegenerative disorder and age related problems. Copyright © 2016 Elsevier Inc. All rights reserved.

Extracellular cyclic ADP-ribose potentiates ACh-induced contraction in bovine tracheal smooth muscle.

PubMed

Franco, L; Bruzzone, S; Song, P; Guida, L; Zocchi, E; Walseth, T F; Crimi, E; Usai, C; De Flora, A; Brusasco, V

2001-01-01

Cyclic ADP-ribose (cADPR), a universal calcium releaser, is generated from NAD(+) by an ADP-ribosyl cyclase and is degraded to ADP-ribose by a cADPR hydrolase. In mammals, both activities are expressed as ectoenzymes by the transmembrane glycoprotein CD38. CD38 was identified in both epithelial cells and smooth myocytes isolated from bovine trachea. Intact tracheal smooth myocytes (TSMs) responded to extracellular cADPR (100 microM) with an increase in intracellular calcium concentration ([Ca(2+)](i)) both at baseline and after acetylcholine (ACh) stimulation. The nonhydrolyzable analog 3-deaza-cADPR (10 nM) elicited the same effects as cADPR, whereas the cADPR antagonist 8-NH(2)-cADPR (10 microM) inhibited both basal and ACh-stimulated [Ca(2+)](i) levels. Extracellular cADPR or 3-deaza-cADPR caused a significant increase of ACh-induced contraction in tracheal smooth muscle strips, whereas 8-NH(2)-cADPR decreased it. Tracheal mucosa strips, by releasing NAD(+), enhanced [Ca(2+)](i) in isolated TSMs, and this increase was abrogated by either NAD(+)-ase or 8-NH(2)-cADPR. These data suggest the existence of a paracrine mechanism whereby mucosa-released extracellular NAD(+) plays a hormonelike function and cADPR behaves as second messenger regulating calcium-related contractility in TSMs.

New multipotent tetracyclic tacrines with neuroprotective activity.

PubMed

Marco-Contelles, José; León, Rafael; de los Ríos, Cristóbal; García, Antonio G; López, Manuela G; Villarroya, Mercedes

2006-12-15

The synthesis and the biological evaluation (neuroprotection, voltage dependent calcium channel blockade, AChE/BuChE inhibitory activity and propidium binding) of new multipotent tetracyclic tacrine analogues (5-13) are described. Compounds 7, 8 and 11 showed a significant neuroprotective effect on neuroblastoma cells subjected to Ca(2+) overload or free radical induced toxicity. These compounds are modest AChE inhibitors [the best inhibitor (11) is 50-fold less potent than tacrine], but proved to be very selective, as for most of them no BuChE inhibition was observed. In addition, the propidium displacement experiments showed that these compounds bind AChE to the peripheral anionic site (PAS) of AChE and, consequently, are potential agents that can prevent the aggregation of beta-amyloid. Overall, compound 8 is a modest and selective AChE inhibitor, but an efficient neuroprotective agent against 70mM K(+) and 60microM H(2)O(2). Based on these results, some of these molecules can be considered as lead candidates for the further development of anti-Alzheimer drugs.

Catalytic Enantioselective Synthesis of Quaternary Carbon Stereocenters

PubMed Central

Quasdorf, Kyle W.; Overman, Larry E.

2015-01-01

Preface Quaternary carbon stereocenters–carbon atoms to which four distinct carbon substituents are attached–are common features of molecules found in nature. However, prior to recent advances in chemical catalysis, there were few methods available for constructing single stereoisomers of this important structural motif. Here we discuss the many catalytic enantioselective reactions developed during the past decade for synthesizing organic molecules containing such carbon atoms. This progress now makes it possible to selectively incorporate quaternary stereocenters in many high-value organic molecules for use in medicine, agriculture, and other areas. PMID:25503231

Nicotine withdrawal-induced inattention is absent in alpha7 nAChR knockout mice

PubMed Central

Higa, K. K.; Grim, A.; Kamenski, M. E.; van Enkhuizen, J.; Zhou, X.; Li, K.; Naviaux, J. C.; Wang, L.; Naviaux, R. K.; Geyer, M. A.; Markou, A.; Young, J. W.

2017-01-01

Rationale Smoking is the leading cause of preventable death in the U.S., but quit attempts result in withdrawal-induced cognitive dysfunction and predicts relapse. Greater understanding of the neural mechanism(s) underlying these cognitive deficits is required to develop targeted treatments to aid quit attempts. Objectives We examined nicotine withdrawal-induced inattention in mice lacking the α7 nicotinic acetylcholine receptor (nAChR) using the 5-choice continuous performance test (5C-CPT). Methods Mice were trained in the 5C-CPT prior to osmotic minipump implantation containing saline or nicotine. Experiment 1 used 40 mg/kg/day nicotine treatment and tested C57BL/6 mice 4, 28, and 52 h after pump removal. Experiment 2 used 14 and 40 mg/kg/day nicotine treatment in α7 nAChR knockout (KO) and wildtype (WT) littermates tested 4 h after pump removal. Subsets of WT mice were sacrificed before and after pump removal to assess changes in receptor expression associated with nicotine administration and withdrawal. Results Nicotine withdrawal impaired attention in the 5C-CPT, driven by response inhibition and target detection deficits. The overall attentional deficit was absent in α7 nAChR KO mice despite response disinhibition in these mice. Synaptosomal glutamate mGluR5 and dopamine D4 receptor expression were reduced during chronic nicotine but increased during withdrawal, potentially contributing to cognitive deficits. Conclusions The α7 nAChR may underlie nicotine withdrawal-induced deficits in target detection but is not required for response disinhibition deficits. Alterations to the glutamatergic and dopaminergic pathways may also contribute to withdrawal-induced attentional deficits, providing novel targets to alleviate the cognitive symptoms of withdrawal during quit attempts. PMID:28243714

Effects of Acetylcholinesterase Inhibitors on Nutritional Status in Elderly Patients with Dementia: A 6-month Follow-up Study.

PubMed

Soysal, P; Isik, A T

2016-04-01

Nutritional status is one of the factors that affects disease progression, morbidity and mortality in elderly patients with dementia. The present study aimed to evaluate the effect of acetylcholinesterase inhibitor (AchEI) therapy on nutritional status and food intake in the elderly. Newly diagnosed patients with dementia, who underwent comprehensive geriatric assessment (CGA) and were followed at regular intervals, were retrospectively evaluated. A total of 116 patients, who began to receive AchEI therapy and completed 6-month follow-up period under this treatment, were enrolled in the study. Socio-demographic characteristics and data on comorbidity, polypharmacy, cognitive function, depression, activities of daily living and nutritional status (weight, Body Mass Index (BMI), Mini Nutritional Assessment (MNA)-Short Form) were recorded. The mean age of the patients was 78.0±8.9 years. There was no significant difference between baseline and 6-month BMI, weight and MNA scores of dementia patients who received AchEI therapy (p>0.05). With regard to the relation between changes in BMI, weight and MNA on the 6th month versus baseline, and donepezil, rivastigmine and galantamine therapies, no difference was determined (p>0.05). However, no worsening in food intake was observed (kappa: 0.377). When the effects of each AchEI on food intake were compared, food intake in rivastigmine treated patients was not decreased as much as it was in galantamine or donepezil treated patients (p<0.05). AchEI therapy has no unfavorable effect on nutritional status or weight in elderly patients with different types of dementia, but it seems that food intake is better in those treated by rivastigmine patch.

Sequential character of low-energy ternary and quaternary nuclear fission

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kadmensky, S. G., E-mail: kadmensky@phys.vsu.ru; Bulychev, A. O.

2016-09-15

An analysis of low-energy true ternary (quaternary) nuclear fission leads to the conclusion that these fission modes have a sequential two-step (three-step) character such that the emission of a third particle (third and fourth particles) and the separation of fission fragments occur at distinctly different instants, in contrast to the simultaneous emergence of all fission products in the case of onestep ternary (quaternary) fission. This conclusion relies on the following arguments. First, the emission of a third particle (third and fourth particles) from a fissile nucleus is due to a nonevaporative mechanism associated with a nonadiabatic character of the collectivemore » deformation motion of this nucleus at the stages preceding its scission. Second, the axial symmetry of the deformed fissile compound nucleus and the direction of its symmetry axis both remain unchanged at all stages of ternary (quaternary) fission. This circumstancemakes it possible to explain themechanism of the appearance of observed anisotropies and T — odd asymmeries in the angular distributions of products of ternary (quaternary) nuclear fission. Third, the T —odd asymmetry discovered experimentally in ternary nuclear fission induced by cold polarized neutrons obeys the T —invariance condition only in the case of a sequential two-step (three-step) character of true ternary (quaternary) nuclear fission. At the same time, this asymmetry is not a T —invariant quantity in the case of the simultaneous emission of products of true ternary (quaternary) nuclear fission from the fissile compound nucleus.« less

Draft Genome Sequence of Aldehyde-Degrading Strain Halomonas axialensis ACH-L-8

PubMed Central

Ye, Jun; Ren, Chong; Shan, Xiexie

2016-01-01

Halomonas axialensis ACH-L-8, a deep-sea strain isolated from the South China Sea, has the ability to degrade aldehydes. Here, we present an annotated draft genome sequence of this species, which could provide fundamental molecular information on the aldehydes-degrading mechanism. PMID:27081145

Development of radiohalogenated muscarinic ligands for the in vivo imaging of m-AChR by nuclear medicine techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

McPherson, D.W.; Luo, H.; Knapp, F.F. Jr.

1994-06-01

Alterations in the density of acetylcholinergic muscarinic receptors (m-AChR) have been observed in various dementias. This has spurred interest in the development of radiohalogenated ligands which can be used for the non-invasive in vivo detection of m-AChR by nuclear medicine techniques. We have developed a new ligand 1-azabicyclo[2.2.2]oct-3-yl ({alpha}-hydroxy-{alpha}-(1-iodo-1-propen-3-yl)-{alpha}-phenylacetate (IQNP,12) which demonstrates high affinity for the muscarinic receptor. When labeled with radioiodine it has been shown to be selective and specific for m-ACHR. Initial studies on the separation and in vivo evaluation of the various isomers of IQNP have shown that the stereochemistry of the chiral centers and the configurationmore » around the double bond play an important role in m-AChR subtype specificity. In vivo evaluation of these stereoisomers demonstrate that E-(R,R)-IQNP has a high affinity for the M{sub 1} muscarinic subtype while Z-(R,R)-IQNP demonstrate a high affinity for M{sub 1} and M{sub 2} receptor subtypes. These data demonstrate IQNP (12) has potential for use in the non-evasive in vivo detection of m-AChR by single photon emission computed tomography (SPECT). A brominated analogue, ``BrQNP,`` in which the iodine has been replaced by a bromine atom, has also been prepared and was shown to block the in vivo uptake of IQNP in the brain and heart and therefore has potential for positron emission tomographic (PET) studies of m-AChR.« less

Does Your Patient's Urine Turns Dark? Alkaptonuria and Low Back Ache: A Literature Review.

PubMed

Kanniyan, Kalaivanan; Pathak, Aditya C; Dhammi, Ish Kumar; Jain, Anil Kumar

2014-01-01

Alkaptonuria is a very rare inborn error of amino acid metabolism due to deficient homogentisic acid (HGA) oxidase enzyme leading to accumulation of HGA in plasma, cartilage, other tissues of human body and its excretion in urine. It has both systemic and peripheral signs and symptoms. Though low back is a common symptom of alkaptonuria but, in the absence of ochronosis it is rare. Alkaptonuria itself is very rare occurrence with no specific treatment option available to reverse the effect as yet. A 38-year-old male, embroidery worker presented with chronic low back ache with history of staining of clothes in infancy. Later on laboratory and the radiological investigation patient was diagnosed to have alkaptonuria without ochronosis. No other systemic manifestation was present. Patient was treated conservatively and responded well. Though alkaptonuria is a very rare disease, and the occurrence of low back-ache in absence of ochronosis is much rarer. One must be aware of this inborn error of metabolism. Early diagnosis though being "diagnosis of exclusion" for low back-ache, high index of suspicion is advantageous as symptomatic treatment of the alkaptonuria can be initiated and evaluation of other systemic organs can be done in early stages itself.

Blockade of Neuronal α7-nAChR by α-Conotoxin ImI Explained by Computational Scanning and Energy Calculations

PubMed Central

Yu, Rilei; Craik, David J.; Kaas, Quentin

2011-01-01

α-Conotoxins potently inhibit isoforms of nicotinic acetylcholine receptors (nAChRs), which are essential for neuronal and neuromuscular transmission. They are also used as neurochemical tools to study nAChR physiology and are being evaluated as drug leads to treat various neuronal disorders. A number of experimental studies have been performed to investigate the structure-activity relationships of conotoxin/nAChR complexes. However, the structural determinants of their binding interactions are still ambiguous in the absence of experimental structures of conotoxin-receptor complexes. In this study, the binding modes of α-conotoxin ImI to the α7-nAChR, currently the best-studied system experimentally, were investigated using comparative modeling and molecular dynamics simulations. The structures of more than 30 single point mutants of either the conotoxin or the receptor were modeled and analyzed. The models were used to explain qualitatively the change of affinities measured experimentally, including some nAChR positions located outside the binding site. Mutational energies were calculated using different methods that combine a conformational refinement procedure (minimization with a distance dependent dielectric constant or explicit water, or molecular dynamics using five restraint strategies) and a binding energy function (MM-GB/SA or MM-PB/SA). The protocol using explicit water energy minimization and MM-GB/SA gave the best correlations with experimental binding affinities, with an R2 value of 0.74. The van der Waals and non-polar desolvation components were found to be the main driving force for binding of the conotoxin to the nAChR. The electrostatic component was responsible for the selectivity of the various ImI mutants. Overall, this study provides novel insights into the binding mechanism of α-conotoxins to nAChRs and the methodological developments reported here open avenues for computational scanning studies of a rapidly expanding range of wild

Design, synthesis, and pharmacological evaluation of 2-amino-5-nitrothiazole derived semicarbazones as dual inhibitors of monoamine oxidase and cholinesterase: effect of the size of aryl binding site.

PubMed

Tripathi, Rati K P; M Sasi, Vishnu; Gupta, Sukesh K; Krishnamurthy, Sairam; Ayyannan, Senthil R

2018-12-01

A series of 2-amino-5-nitrothiazole derived semicarbazones were designed, synthesised and investigated for MAO and ChE inhibition properties. Most of the compounds showed preferential inhibition towards MAO-B. Compound 4, (1-(1-(4-Bromophenyl)ethylidene)-4-(5-nitrothiazol-2-yl)semicarbazide) emerged as lead candidate (IC 50  = 0.212 µM, SI = 331.04) against MAO-B; whereas compounds 21 1-(5-Bromo-2-oxoindolin-3-ylidene)-4-(5-nitrothiazol-2-yl)semicarbazide (IC 50  = 0.264 µM) and 17 1-((4-Chlorophenyl) (phenyl)methylene)-4-(5-nitrothiazol-2-yl)semicarbazide (IC 50  = 0.024 µM) emerged as lead AChE and BuChE inhibitors respectively; with activity of compound 21 almost equivalent to tacrine. Kinetic studies indicated that compound 4 exhibited competitive and reversible MAO-B inhibition while compounds 21 and 17 showed mixed-type of AChE and BuChE inhibition respectively. Docking studies revealed that these compounds were well-accommodated within MAO-B and ChE active sites through stable hydrogen bonding and/or hydrophobic interactions. This study revealed the requirement of small heteroaryl ring at amino terminal of semicarbazone template for preferential inhibition and selectivity towards MAO-B. Our results suggest that 5-nitrothiazole derived semicarbazones could be further exploited for its multi-targeted role in development of anti-neurodegenerative agents. [Formula: see text] A library of 2-amino-5-nitrothiazole derived semicarbazones (4-21) was designed, synthesised and evaluated for in vitro MAO and ChE inhibitory activity. Compounds 4, 21 and 17 (shown) have emerged as lead MAO-B (IC 50 :0.212 µM, competitive and reversible), AChE (IC 50 :0.264 µM, mixed and reversible) and BuChE (IC 50 :0.024 µM, mixed and reversible) inhibitor respectively. SAR studies disclosed several structural aspects significant for potency and selectivity and indicated the role of size of aryl binding site in potency and selectivity towards MAO

Synthesis and bioevaluation of new tacrine-cinnamic acid hybrids as cholinesterase inhibitors against Alzheimer's disease.

PubMed

Chen, Yao; Zhu, Jie; Mo, Jun; Yang, Hongyu; Jiang, Xueyang; Lin, Hongzhi; Gu, Kai; Pei, Yuqiong; Wu, Liang; Tan, Renxiang; Hou, Jing; Chen, Jingyi; Lv, Yang; Bian, Yaoyao; Sun, Haopeng

2018-12-01

Small molecule cholinesterases inhibitor (ChEI) provides an effective therapeutic strategy to treat Alzheimer's disease (AD). Currently, the discovery of new ChEI with multi-target effect is still of great importance. Herein, we report the synthesis, structure-activity relationship study and biological evaluation of a series of tacrine-cinnamic acid hybrids as new ChEIs. All target compounds are evaluated for their in vitro cholinesterase inhibitory activities. The representatives which show potent activity on cholinesterase, are evaluated for the amyloid β-protein self-aggregation inhibition and in vivo assays. The optimal compound 19, 27, and 30 (human AChE IC 50  = 10.2 ± 1.2, 16.5 ± 1.7, and 15.3 ± 1.8 nM, respectively) show good performance in ameliorating the scopolamine-induced cognition impairment and preliminary safety in hepatotoxicity evaluation. These compounds deserve further evaluation for the development of new therapeutic agents against AD.

Resorcinol-, catechol- and saligenin-based bronchodilating β2-agonists as inhibitors of human cholinesterase activity.

PubMed

Bosak, Anita; Knežević, Anamarija; Gazić Smilović, Ivana; Šinko, Goran; Kovarik, Zrinka

2017-12-01

We investigated the influence of bronchodilating β2-agonists on the activity of human acetylcholinesterase (AChE) and usual, atypical and fluoride-resistant butyrylcholinesterase (BChE). We determined the inhibition potency of racemate and enantiomers of fenoterol as a resorcinol derivative, isoetharine and epinephrine as catechol derivatives and salbutamol and salmeterol as saligenin derivatives. All of the tested compounds reversibly inhibited cholinesterases with K i constants ranging from 9.4 μM to 6.4 mM and had the highest inhibition potency towards usual BChE, but generally none of the cholinesterases displayed any stereoselectivity. Kinetic and docking results revealed that the inhibition potency of the studied compounds could be related to the size of the hydroxyaminoethyl chain on the benzene ring. The additional π-π interaction of salmeterol's benzene ring and Trp286 and hydrogen bond with His447 probably enhanced inhibition by salmeterol which was singled out as the most potent inhibitor of all the cholinesterases.

Vagus nerve stimulation mediates protection from kidney ischemia-reperfusion injury through α7nAChR+ splenocytes.

PubMed

Inoue, Tsuyoshi; Abe, Chikara; Sung, Sun-Sang J; Moscalu, Stefan; Jankowski, Jakub; Huang, Liping; Ye, Hong; Rosin, Diane L; Guyenet, Patrice G; Okusa, Mark D

2016-05-02

The nervous and immune systems interact in complex ways to maintain homeostasis and respond to stress or injury, and rapid nerve conduction can provide instantaneous input for modulating inflammation. The inflammatory reflex referred to as the cholinergic antiinflammatory pathway regulates innate and adaptive immunity, and modulation of this reflex by vagus nerve stimulation (VNS) is effective in various inflammatory disease models, such as rheumatoid arthritis and inflammatory bowel disease. Effectiveness of VNS in these models necessitates the integration of neural signals and α7 nicotinic acetylcholine receptors (α7nAChRs) on splenic macrophages. Here, we sought to determine whether electrical stimulation of the vagus nerve attenuates kidney ischemia-reperfusion injury (IRI), which promotes the release of proinflammatory molecules. Stimulation of vagal afferents or efferents in mice 24 hours before IRI markedly attenuated acute kidney injury (AKI) and decreased plasma TNF. Furthermore, this protection was abolished in animals in which splenectomy was performed 7 days before VNS and IRI. In mice lacking α7nAChR, prior VNS did not prevent IRI. Conversely, adoptive transfer of VNS-conditioned α7nAChR splenocytes conferred protection to recipient mice subjected to IRI. Together, these results demonstrate that VNS-mediated attenuation of AKI and systemic inflammation depends on α7nAChR-positive splenocytes.

Attenuated nicotine-like effects of varenicline but not other nicotinic ACh receptor agonists in monkeys receiving nicotine daily.

PubMed

Cunningham, Colin S; Moerke, Megan J; Javors, Martin A; Carroll, F Ivy; McMahon, Lance R

2016-12-01

Chronic treatment can differentially impact the effects of pharmacologically related drugs that differ in receptor selectivity and efficacy. The impact of daily nicotine treatment on the effects of nicotinic ACh receptor (nAChR) agonists was examined in two groups of rhesus monkeys discriminating nicotine (1.78 mg·kg -1 base weight) from saline. One group received additional nicotine treatment post-session (1.78 mg·kg -1 administered five times daily, each dose 2 h apart; i.e. Daily group), and the second group did not (Intermittent group). Daily repeated nicotine treatment produced a time-related increase in saliva cotinine. There was no significant difference in the ED 50 values of the nicotine discriminative stimulus between the Daily and Intermittent group. Mecamylamine antagonized the effects of nicotine, whereas dihydro-β-erythroidine did not. Midazolam produced 0% nicotine-lever responding. The nAChR agonists epibatidine, RTI-36, cytisine and varenicline produced >96% nicotine-lever responding in the Intermittent group. The respective maximum effects in the Daily group were 100, 72, 59 and 28%, which shows that the ability of varenicline to produce nicotine-like responding was selectively decreased in the Daily as compared with the Intermittent group. When combined with nicotine, both varenicline and cytisine increased the potency of nicotine to produce discriminative stimulus effects. Nicotine treatment has a greater impact on the sensitivity to the effects of varenicline as compared with some other nAChR agonists. Collectively, these results strongly suggest that varenicline differs from nicotine in its selectivity for multiple nAChR subtypes. © 2016 The British Pharmacological Society.

Attenuated nicotine‐like effects of varenicline but not other nicotinic ACh receptor agonists in monkeys receiving nicotine daily

PubMed Central

Cunningham, Colin S; Moerke, Megan J; Javors, Martin A; Carroll, F Ivy

2016-01-01

Background and Purpose Chronic treatment can differentially impact the effects of pharmacologically related drugs that differ in receptor selectivity and efficacy. Experimental Approach The impact of daily nicotine treatment on the effects of nicotinic ACh receptor (nAChR) agonists was examined in two groups of rhesus monkeys discriminating nicotine (1.78 mg·kg−1 base weight) from saline. One group received additional nicotine treatment post‐session (1.78 mg·kg−1 administered five times daily, each dose 2 h apart; i.e. Daily group), and the second group did not (Intermittent group). Key Results Daily repeated nicotine treatment produced a time‐related increase in saliva cotinine. There was no significant difference in the ED50 values of the nicotine discriminative stimulus between the Daily and Intermittent group. Mecamylamine antagonized the effects of nicotine, whereas dihydro‐β‐erythroidine did not. Midazolam produced 0% nicotine‐lever responding. The nAChR agonists epibatidine, RTI‐36, cytisine and varenicline produced >96% nicotine‐lever responding in the Intermittent group. The respective maximum effects in the Daily group were 100, 72, 59 and 28%, which shows that the ability of varenicline to produce nicotine‐like responding was selectively decreased in the Daily as compared with the Intermittent group. When combined with nicotine, both varenicline and cytisine increased the potency of nicotine to produce discriminative stimulus effects. Conclusion and Implications Nicotine treatment has a greater impact on the sensitivity to the effects of varenicline as compared with some other nAChR agonists. Collectively, these results strongly suggest that varenicline differs from nicotine in its selectivity for multiple nAChR subtypes. PMID:27667659

nAChR dysfunction as a common substrate for schizophrenia and comorbid nicotine addiction: current trends and perspectives

PubMed Central

Parikh, Vinay; Kutlu, Munir Gunes; Gould, Thomas J.

2016-01-01

Introduction The prevalence of tobacco use in the population with schizophrenia is enormously high. Moreover, nicotine dependence is found to be associated with symptom severity and poor outcome in patients with schizophrenia. The neurobiological mechanisms that explain schizophrenia-nicotine dependence comorbidity are not known. This study systematically reviews the evidence highlighting the contribution of nicotinic acetylcholine receptors (nAChRs) to nicotine abuse in schizophrenia. Methods Electronic data bases (Medline, Google Scholar, and Web of Science) were searched using the selected key words that match the aims set forth for this review. A total of 275 articles were used for the qualitative synthesis of this review. Results Substantial evidence from preclinical and clinical studies indicated that dysregulation of α7 and β2-subunit containing nAChRs account for the cognitive and affective symptoms of schizophrenia and nicotine use may represent a strategy to remediate these symptoms. Additionally, recent meta-analyses proposed that early tobacco use may itself increase the risk of developing schizophrenia. Genetic studies demonstrating that nAChR dysfunction that may act as a shared vulnerability factor for comorbid tobacco dependence and schizophrenia were found to support this view. The development of nAChR modulators was considered an effective therapeutic strategy to ameliorate psychiatric symptoms and to promote smoking cessation in schizophrenia patients. Conclusions The relationship between schizophrenia and smoking is complex. While the debate for the self-medication versus addiction vulnerability hypothesis continues, it is widely accepted that a dysfunction in the central nAChRs represent a common substrate for various symptoms of schizophrenia and comorbid nicotine dependence. PMID:26803692

Droplet-based microfluidics for dose-response assay of enzyme inhibitors by electrochemical method.

PubMed

Gu, Shuqing; Lu, Youlan; Ding, Yaping; Li, Li; Zhang, Fenfen; Wu, Qingsheng

2013-09-24

A simple but robust droplet-based microfluidic system was developed for dose-response enzyme inhibition assay by combining concentration gradient generation method with electrochemical detection method. A slotted-vials array and a tapered tip capillary were used for reagents introduction and concentration gradient generation, and a polydimethylsiloxane (PDMS) microfluidic chip integrated with microelectrodes was used for droplet generation and electrochemical detection. Effects of oil flow rate and surfactant on electrochemical sensing were investigated. This system was validated by measuring dose-response curves of three types of acetylcholinesterase (AChE) inhibitors, including carbamate pesticide, organophosphorus pesticide, and therapeutic drugs regulating Alzheimer's disease. Carbaryl, chlorpyrifos, and tacrine were used as model analytes, respectively, and their IC50 (half maximal inhibitory concentration) values were determined. A whole enzyme inhibition assay was completed in 6 min, and the total consumption of reagents was less than 5 μL. This microfluidic system is applicable to many biochemical reactions, such as drug screening and kinetic studies, as long as one of the reactants or products is electrochemically active. Copyright © 2013 Elsevier B.V. All rights reserved.

Assessment of the expression and role of the α1-nAChR subunit in efferent cholinergic function during the development of the mammalian cochlea.

PubMed

Roux, Isabelle; Wu, Jingjing Sherry; McIntosh, J Michael; Glowatzki, Elisabeth

2016-08-01

Hair cell (HC) activity in the mammalian cochlea is modulated by cholinergic efferent inputs from the brainstem. These inhibitory inputs are mediated by calcium-permeable nicotinic acetylcholine receptors (nAChRs) containing α9- and α10-subunits and by subsequent activation of calcium-dependent potassium channels. Intriguingly, mRNAs of α1- and γ-nAChRs, subunits of the "muscle-type" nAChR have also been found in developing HCs (Cai T, Jen HI, Kang H, Klisch TJ, Zoghbi HY, Groves AK. J Neurosci 35: 5870-5883, 2015; Scheffer D, Sage C, Plazas PV, Huang M, Wedemeyer C, Zhang DS, Chen ZY, Elgoyhen AB, Corey DP, Pingault V. J Neurochem 103: 2651-2664, 2007; Sinkkonen ST, Chai R, Jan TA, Hartman BH, Laske RD, Gahlen F, Sinkkonen W, Cheng AG, Oshima K, Heller S. Sci Rep 1: 26, 2011) prompting proposals that another type of nAChR is present and may be critical during early synaptic development. Mouse genetics, histochemistry, pharmacology, and whole cell recording approaches were combined to test the role of α1-nAChR subunit in HC efferent synapse formation and cholinergic function. The onset of α1-mRNA expression in mouse HCs was found to coincide with the onset of the ACh response and efferent synaptic function. However, in mouse inner hair cells (IHCs) no response to the muscle-type nAChR agonists (±)-anatoxin A, (±)-epibatidine, (-)-nicotine, or 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP) was detected, arguing against the presence of an independent functional α1-containing muscle-type nAChR in IHCs. In α1-deficient mice, no obvious change of IHC efferent innervation was detected at embryonic day 18, contrary to the hyperinnervation observed at the neuromuscular junction. Additionally, ACh response and efferent synaptic activity were detectable in α1-deficient IHCs, suggesting that α1 is not necessary for assembly and membrane targeting of nAChRs or for efferent synapse formation in IHCs.

Assessment of the expression and role of the α1-nAChR subunit in efferent cholinergic function during the development of the mammalian cochlea

PubMed Central

Wu (武靜靜), Jingjing Sherry; McIntosh, J. Michael; Glowatzki, Elisabeth

2016-01-01

Hair cell (HC) activity in the mammalian cochlea is modulated by cholinergic efferent inputs from the brainstem. These inhibitory inputs are mediated by calcium-permeable nicotinic acetylcholine receptors (nAChRs) containing α9- and α10-subunits and by subsequent activation of calcium-dependent potassium channels. Intriguingly, mRNAs of α1- and γ-nAChRs, subunits of the “muscle-type” nAChR have also been found in developing HCs (Cai T, Jen HI, Kang H, Klisch TJ, Zoghbi HY, Groves AK. J Neurosci 35: 5870–5883, 2015; Scheffer D, Sage C, Plazas PV, Huang M, Wedemeyer C, Zhang DS, Chen ZY, Elgoyhen AB, Corey DP, Pingault V. J Neurochem 103: 2651–2664, 2007; Sinkkonen ST, Chai R, Jan TA, Hartman BH, Laske RD, Gahlen F, Sinkkonen W, Cheng AG, Oshima K, Heller S. Sci Rep 1: 26, 2011) prompting proposals that another type of nAChR is present and may be critical during early synaptic development. Mouse genetics, histochemistry, pharmacology, and whole cell recording approaches were combined to test the role of α1-nAChR subunit in HC efferent synapse formation and cholinergic function. The onset of α1-mRNA expression in mouse HCs was found to coincide with the onset of the ACh response and efferent synaptic function. However, in mouse inner hair cells (IHCs) no response to the muscle-type nAChR agonists (±)-anatoxin A, (±)-epibatidine, (−)-nicotine, or 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP) was detected, arguing against the presence of an independent functional α1-containing muscle-type nAChR in IHCs. In α1-deficient mice, no obvious change of IHC efferent innervation was detected at embryonic day 18, contrary to the hyperinnervation observed at the neuromuscular junction. Additionally, ACh response and efferent synaptic activity were detectable in α1-deficient IHCs, suggesting that α1 is not necessary for assembly and membrane targeting of nAChRs or for efferent synapse formation in IHCs. PMID:27098031

Tertiary and Quaternary Research with Remote Sensing Methods

NASA Technical Reports Server (NTRS)

Conel, J. E.

1985-01-01

Problems encountered in mapping the Quaternary section of the Wind River Region using remote sensing methods are discussed. Analysis of the stratigraphic section is a fundamental aspect of the geologic study of sedimentary basins. Stratigraphic analysis of post-Cretaceous rocks in the Wind River Basin encounters problems of a distinctly different character from those involved in studying the pre-Cretaceous section. The interior of the basin is predominantly covered by Tertiary and Quaternary sediments. These rocks, except on the basin margin to the north, are mostly flat lying or gently dipping. The Tertiary section consists of sandstones, siltstones, and tuffaceous sediments, some variegated, but in general poorly bedded and of great lithologic similarity. The Quaternary sediments consist of terrace, fan, and debris tongue deposits, unconsolidated alluvium occupying the bottoms of modern watercourses, deposits of eolian origin and tufa. Terrace and fan deposits are compositionally diverse and reflect the lithologic diversity of the source terranes.

77 FR 40148 - Proposed Collection of Information: ACH Vendor/Miscellaneous Payment Enrollment Form

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-06

.../Miscellaneous Payment Enrollment Form AGENCY: Financial Management Service, Fiscal Service, Treasury. ACTION: Notice and request for comments. SUMMARY: The Financial Management Service, as part of its continuing... Financial Management Service solicits comments concerning the SF 3881 ``ACH Vendor/Miscellaneous Payment...

Neuroinflammatory Pathobiology in Gulf War Illness: Characterization with an Animal Model

DTIC Science & Technology

2013-08-01

GFAP,IL6,CCL2, TNF, L118, Lif, IL10 Hip, Ctx Ctx Ctx CORT=corticosterone;(200mg/L) for days 7-14 P8= pyridostigmine bromide ;P8(2.5 mg/kg/day, s.c...reversible acetylcholinesterase (AChE) inhibitor pyridostigmine bromide (PB), the insect repellent DEET and, potentially, the nerve agent, sarin. These...acetylcholinesterase (AChE) inhibitor, pyridostigmine bromide (PB), the insect repellent, DEET, and, potentially, acutely to the nerve agent sarin. Previously, we

Is Quaternary geology ready for the future?

NASA Astrophysics Data System (ADS)

Ritter, Dale F.

1996-07-01

Armed with a better understanding of process and an array of developing dating techniques, Quaternary geology is poised to achieve greater recognition in the general scientific community. This recognition however, will require some thought adjustment. Quaternary geologists will have to convince government, industry and a variety of scientific groups that they possess unique training and expertise that is needed as part of the thrust to fully understand and/or resolve major scientific problems. Therefore, future research and education efforts should not focus on developing a rigidly defined identity within geoscience, but instead should seek ways to be integrated with interdisciplinary teams that will investigate complex environmental and climate change problems. Such a scenaria creates and enermous dilemma for Quaternary geologists because they will derive greater intellectual stimulation from scientists working in discplines other than geology, and their scientific collaboratiors will most likely not be their academic colleagues. This outward expansion of our scientific network will require the development of interdsciplinary research collaboration and/or degree-granting programs at the graduate level. To accomplish such goals, universities must resist "turf protection", and funding agencies muts become more efficient at facilitating interdisciplinary research.

Origin of bonebeds in Quaternary tank deposits

NASA Astrophysics Data System (ADS)

Araújo-Júnior, Hermínio Ismael de; Porpino, Kleberson de Oliveira; Bergqvist, Lílian Paglarelli

2017-07-01

Tank deposits are an exceptional type of fossiliferous deposit and bear a remarkably fossil record of the Pleistocene megafauna of South America, particularly of Brazil. The taphonomy of vertebrate remains preserved in this type of environmental context was clearly driven by climate, similarly to most of the Quaternary continental fossil record. The formation of the vertebrates fossil record in tank deposits was influenced by the climate seasonality typical of arid climate. The taphonomic history of most tank deposits is a consequence of this seasonality and, as a result, the paleoecological data preserved in their fossil assemblages is reliable with respect to paleobiological and paleoenvironmental settings of the Quaternary ecosystems of the Brazilian Intertropical Region (BIR). Other tank deposits experienced an unusual taphonomic history that, besides climate, was affected by recurrent events of reworking produced by the depositional agents dominant in the surrounding alluvial plains. The conclusions obtained here concerning the main taphonomic settings and formative processes that characterize fossil vertebrate assemblages of tank deposits will help further studies aimed to recover information on the paleoecology of Quaternary fauna collected in such deposits by allowing a better understanding of their time and spatial resolutions and other potential biases.

DNA Barcoding through Quaternary LDPC Codes

PubMed Central

Tapia, Elizabeth; Spetale, Flavio; Krsticevic, Flavia; Angelone, Laura; Bulacio, Pilar

2015-01-01

For many parallel applications of Next-Generation Sequencing (NGS) technologies short barcodes able to accurately multiplex a large number of samples are demanded. To address these competitive requirements, the use of error-correcting codes is advised. Current barcoding systems are mostly built from short random error-correcting codes, a feature that strongly limits their multiplexing accuracy and experimental scalability. To overcome these problems on sequencing systems impaired by mismatch errors, the alternative use of binary BCH and pseudo-quaternary Hamming codes has been proposed. However, these codes either fail to provide a fine-scale with regard to size of barcodes (BCH) or have intrinsic poor error correcting abilities (Hamming). Here, the design of barcodes from shortened binary BCH codes and quaternary Low Density Parity Check (LDPC) codes is introduced. Simulation results show that although accurate barcoding systems of high multiplexing capacity can be obtained with any of these codes, using quaternary LDPC codes may be particularly advantageous due to the lower rates of read losses and undetected sample misidentification errors. Even at mismatch error rates of 10−2 per base, 24-nt LDPC barcodes can be used to multiplex roughly 2000 samples with a sample misidentification error rate in the order of 10−9 at the expense of a rate of read losses just in the order of 10−6. PMID:26492348

DNA Barcoding through Quaternary LDPC Codes.

PubMed

Tapia, Elizabeth; Spetale, Flavio; Krsticevic, Flavia; Angelone, Laura; Bulacio, Pilar

2015-01-01

For many parallel applications of Next-Generation Sequencing (NGS) technologies short barcodes able to accurately multiplex a large number of samples are demanded. To address these competitive requirements, the use of error-correcting codes is advised. Current barcoding systems are mostly built from short random error-correcting codes, a feature that strongly limits their multiplexing accuracy and experimental scalability. To overcome these problems on sequencing systems impaired by mismatch errors, the alternative use of binary BCH and pseudo-quaternary Hamming codes has been proposed. However, these codes either fail to provide a fine-scale with regard to size of barcodes (BCH) or have intrinsic poor error correcting abilities (Hamming). Here, the design of barcodes from shortened binary BCH codes and quaternary Low Density Parity Check (LDPC) codes is introduced. Simulation results show that although accurate barcoding systems of high multiplexing capacity can be obtained with any of these codes, using quaternary LDPC codes may be particularly advantageous due to the lower rates of read losses and undetected sample misidentification errors. Even at mismatch error rates of 10(-2) per base, 24-nt LDPC barcodes can be used to multiplex roughly 2000 samples with a sample misidentification error rate in the order of 10(-9) at the expense of a rate of read losses just in the order of 10(-6).

Evidence for aging theories from the study of a hunter-gatherer people (Ache of Paraguay).

PubMed

Libertini, G

2013-09-01

In the late seventies, a small tribal population of Paraguay, the Ache, living under natural conditions, was studied. Data from this population turn out to be useful for considerations about evolutionary hypotheses on the aging phenomenon. 1) Ache show an age-related increasing mortality, which strongly limits the mean duration of life, as observed in other studies on mammal and bird species. 2) According to current theories on aging, in the wild very few or no individual reach old age and, so, aging cannot be directly influenced by natural selection. However, data from our population show that a significant proportion of the population reaches in the wild 60 and 70 years of age. 3) Data from Ache are also in agreement with the observation about an inverse correlation between extrinsic mortality and deaths due to the age-related increasing mortality. 4) For many gerontologists, the age-related decline of vital functions is a consequence of the gradual decline of cell turnover, genetically determined and regulated by the declining duplication capacities of stem cells. The current interpretation is that these restrictions are a general defense against the proliferation of any tumoral mass. However, among wild Ache cancer is virtually unknown in non-elderly subjects, and only among older individuals are there deaths attributable to oncological diseases. Moreover, fitness decline begins long before oncological diseases have fatal effects in significant numbers. This completely disproves the current hypothesis, because a supposed defense against a deadly disease cannot exterminate a population before the disease begins to kill. These data are consistent with similar data from other species studied under natural conditions, and they bring new arguments against the non-adaptive interpretation of aging and in support of the adaptive interpretation.

Correlation of cholinergic drug induced quenching of acetylcholinesterase bound thioflavin-T fluorescence with their inhibition activity

NASA Astrophysics Data System (ADS)

Islam, Mullah Muhaiminul; Rohman, Mostofa Ataur; Gurung, Arun Bahadur; Bhattacharjee, Atanu; Aguan, Kripamoy; Mitra, Sivaprasad

2018-01-01

The development of new acetylcholinesterase inhibitors (AChEIs) and subsequent assay of their inhibition efficiency is considered to be a key step for AD treatment. The fluorescence intensity of thioflavin-T (ThT) bound in the active site of acetylcholinesterase (AChE) quenches substantially in presence of standard AChEI drugs due to the dynamic replacement of the fluorophore from the AChE active site as confirmed from steady state emission as well as time-resolved fluorescence anisotropy measurement and molecular dynamics simulation in conjunction with docking calculation. The parametrized % quenching data for individual system shows excellent correlation with enzyme inhibition activity measured independently by standard Ellman AChE assay method in a high throughput plate reader system. The results are encouraging towards design of a fluorescence intensity based AChE inhibition assay method and may provide a better toolset to rapidly evaluate as well as develop newer AChE-inhibitors for AD treatment.

NMDA antagonists exert distinct effects in experimental organophosphate or carbamate poisoning in mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dekundy, Andrzej; Kaminski, Rafal M.; Zielinska, Elzbieta

2007-03-15

Organophosphate (OP) and carbamate acetylcholinesterase (AChE) inhibitors produce seizures and lethality in mammals. Anticonvulsant and neuroprotective properties of N-methyl-D-aspartate (NMDA) antagonists encourage the investigation of their effects in AChE inhibitor-induced poisonings. In the present study, the effects of dizocilpine (MK-801, 1 mg/kg) or 3-((RS)-2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP, 10 mg/kg), alone or combined with muscarinic antagonist atropine (1.8 mg/kg), on convulsant and lethal properties of an OP pesticide dichlorvos or a carbamate drug physostigmine, were studied in mice. Both dichlorvos and physostigmine induced dose-dependent seizure activity and lethality. Atropine did not prevent the occurrence of convulsions but decreased the lethal effects ofmore » both dichlorvos and physostigmine. MK-801 or CPP blocked or attenuated, respectively, dichlorvos-induced convulsions. Contrariwise, NMDA antagonists had no effect in physostigmine-induced seizures or lethality produced by dichlorvos or physostigmine. Concurrent pretreatment with atropine and either MK-801 or CPP blocked or alleviated seizures produced by dichlorvos, but not by physostigmine. Both MK-801 and CPP co-administered with atropine enhanced its antilethal effects in both dichlorvos and physostigmine poisoning. In both saline- and AChE inhibitor-treated mice, no interaction of the investigated antidotes with brain cholinesterase was found. The data indicate that both muscarinic ACh and NMDA receptor-mediated mechanisms contribute to the acute toxicity of AChE inhibitors, and NMDA receptors seem critical to OP-induced seizures.« less

Nicotine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone induce cyclooxygenase-2 activity in human gastric cancer cells: Involvement of nicotinic acetylcholine receptor (nAChR) and {beta}-adrenergic receptor signaling pathways

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shin, Vivian Yvonne; Jin, H.C.; Ng, Enders K.O.

Induction of cyclooxygenase-2 (COX-2) associates with cigarette smoke exposure in many malignancies. Nicotine and its derivative, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), are the two important components in cigarette smoke that contributes to cancer development. However, the molecular mechanism(s) by which nicotine or NNK promotes gastric carcinogenesis remains largely unknown. We found that nicotine and NNK significantly enhanced cell proliferation in AGS cells that expressed both alpha7 nicotinic acetylcholine receptor ({alpha}7 nAChR) and {beta}-adrenergic receptors. Treatment of cells with {alpha}-bungarotoxin ({alpha}-BTX, {alpha}7nAChR antagonist) or propranolol ({beta}-adrenergic receptor antagonist) blocked NNK-induced COX-2/PGE{sub 2} and cell proliferation, while nicotine-mediated cell growth and COX-2/PGE{sub 2} induction canmore » only be suppressed by propranolol, but not {alpha}-BTX. Moreover, in contrast to the dependence of growth promoting effect of nicotine on Erk activation, inhibitor of p38 mitogen-activated protein kinase (MAPK) repressed NNK-induced COX-2 upregulation and resulted in suppression of cell growth. In addition, nicotine and NNK mediated COX-2 induction via different receptors to modulate several G1/S transition regulatory proteins and promote gastric cancer cell growth. Selective COX-2 inhibitor (SC-236) caused G1 arrest and abrogated nicotine/NNK-induced cell proliferation. Aberrant expression of cyclin D1 and other G1 regulatory proteins are reversed by blockade of COX-2. These results pointed to the importance of adrenergic and nicotinic receptors in gastric tumor growth through MAPK/COX-2 activation, which may perhaps provide a chemoprevention strategy for cigarette smoke-related gastric carcinogenesis.« less

Understanding the conformational flexibility and electrostatic properties of curcumin in the active site of rhAChE via molecular docking, molecular dynamics, and charge density analysis.

PubMed

Saravanan, Kandasamy; Kalaiarasi, Chinnasamy; Kumaradhas, Poomani

2017-12-01

Acetylcholinesterase (AChE) is an important enzyme responsible for Alzheimer's disease, as per report, keto-enol form of curcumin inhibits this enzyme. The present study aims to understand the binding mechanism of keto-enol curcumin with the recombinant human Acetylcholinesterase (rhAChE) from its conformational flexibility, intermolecular interactions, charge density distribution, and the electrostatic properties at the active site of rhAChE. To accomplish this, a molecular docking analysis of curcumin with the rhAChE was performed, which gives the structure and conformation of curcumin in the active site of rhAChE. Further, the charge density distribution and the electrostatic properties of curcumin molecule (lifted from the active site of rhAChE) were determined from the high level density functional theory (DFT) calculations coupled with the charge density analysis. On the other hand, the curcumin molecule was optimized (gas phase) using DFT method and further, the structure and charge density analysis were also carried out. On comparing the conformation, charge density distribution and the electrostatic potential of the active site form of curcumin with the corresponding gas phase form reveals that the above said properties are significantly altered when curcumin is present in the active site of rhAChE. The conformational stability and the interaction of curcumin in the active site are also studied using molecular dynamics simulation, which shows a large variation in the conformational geometry of curcumin as well as the intermolecular interactions.

Does Your Patient’s Urine Turns Dark? Alkaptonuria and Low Back Ache: A Literature Review

PubMed Central

Kanniyan, Kalaivanan; Pathak, Aditya C; Dhammi, Ish Kumar; Jain, Anil Kumar

2014-01-01

Introduction: Alkaptonuria is a very rare inborn error of amino acid metabolism due to deficient homogentisic acid (HGA) oxidase enzyme leading to accumulation of HGA in plasma, cartilage, other tissues of human body and its excretion in urine. It has both systemic and peripheral signs and symptoms. Though low back is a common symptom of alkaptonuria but, in the absence of ochronosis it is rare. Alkaptonuria itself is very rare occurrence with no specific treatment option available to reverse the effect as yet. Case Report: A 38-year-old male, embroidery worker presented with chronic low back ache with history of staining of clothes in infancy. Later on laboratory and the radiological investigation patient was diagnosed to have alkaptonuria without ochronosis. No other systemic manifestation was present. Patient was treated conservatively and responded well. Conclusion: Though alkaptonuria is a very rare disease, and the occurrence of low back-ache in absence of ochronosis is much rarer. One must be aware of this inborn error of metabolism. Early diagnosis though being “diagnosis of exclusion” for low back-ache, high index of suspicion is advantageous as symptomatic treatment of the alkaptonuria can be initiated and evaluation of other systemic organs can be done in early stages itself. PMID:27298997

AT–1001: a high-affinity α3β4 nAChR ligand with novel nicotine-suppressive pharmacology

PubMed Central

Cippitelli, Andrea; Wu, Jinhua; Gaiolini, Kelly A; Mercatelli, Daniela; Schoch, Jennifer; Gorman, Michelle; Ramirez, Alejandra; Ciccocioppo, Roberto; Khroyan, Taline V; Yasuda, Dennis; Zaveri, Nurulain T; Pascual, Conrado; Xie, Xinmin (Simon); Toll, Lawrence

2015-01-01

Background and Purpose The α3β4 subtype of nicotinic acetylcholine receptors (nAChRs) has been implicated in mediating nicotine reinforcement processes. AT-1001 has been recently described as a high-affinity and selective α3β4 nAChR antagonist that blocks nicotine self-administration in rats. The aim of this study was to investigate the mechanism of action underlying the nicotine-suppressive effects of AT-1001. Experimental Approach Effects of AT-1001 were determined using in vitro assays and rat models of nicotine addiction, and compared with varenicline. Key Results AT-1001 and its analogue AT-1012 were functionally selective as antagonists for α3β4 over α4β2 nAChRs, but not to the same extent as the binding selectivity, and had partial agonist activity at α3β4 nAChRs. In contrast, varenicline was a partial agonist at α4β2, a weak agonist at α3β4 and inhibited α4β2 at a much lower concentration than it inhibited α3β4 nAChRs. AT-1001 and varenicline also had very different in vivo properties. Firstly, AT-1001 did not exhibit reinforcing properties per se while varenicline was self-administered. Secondly, systemic treatment with AT-1001 did not induce reinstatement of nicotine seeking but rather attenuated reinstatement induced by varenicline, as well as nicotine. Finally, unlike varenicline, AT-1001 selectively blocked nicotine self-administration without altering alcohol lever pressing as assessed in an operant co-administration paradigm. Conclusions and Implications These findings describe a more complex AT-1001 in vitro profile than previously appreciated and provide further support for the potential of AT-1001 and congeners as clinically useful compounds for smoking cessation, with a mechanism of action distinct from currently available medications. PMID:25440006

A Review of Butyrylcholinesterase as a Therapeutic Target in the Treatment of Alzheimer’s Disease

PubMed Central

Ballard, Clive; Bullock, Roger; Darreh-Shori, Taher; Somogyi, Monique

2013-01-01

Objective: To examine the role of butyrylcholinesterase (BuChE) in cholinergic signaling and neurologic conditions, such as Alzheimer’s disease (AD). The rationale for inhibiting cholinesterases in the management of AD, including clinical evidence supporting use of the dual acetylcholinesterase (AChE) and BuChE inhibitor rivastigmine, is discussed. Data Sources: PubMed searches were performed using butyrylcholinesterase as a keyword. English-language articles referenced in PubMed as of September 2011 were included. Study Selection and Data Synthesis: English-language articles related to BuChE considered to be of clinical relevance to physicians were included. English-language articles specifically related to AChE were not included, as the role of AChE in cholinergic signaling and the underlying pathology of AD is well documented. Reference lists of included publications were used to supplement the search. Results: AChE and BuChE play a role in cholinergic signaling; BuChE can hydrolyze acetylcholine and compensate for AChE when levels are depleted. In the AD brain, AChE levels decrease, while BuChE levels are reportedly increased or unchanged, with changes becoming more pronounced during the disease course. Furthermore, BuChE genotype may influence AD risk and rate of disease progression. Strategies that increase acetylcholine levels (eg, cholinesterase inhibitors) demonstrate symptomatic efficacy in AD. Rivastigmine has proven cognitive efficacy in clinical trials, and data suggest that its action is mediated, in part, by inhibition of BuChE. Retrospective analyses of clinical trials provide evidence that BuChE genotype may also influence treatment response. Conclusions: AChE-selective inhibitors and a dual AChE and BuChE inhibitor demonstrate symptomatic efficacy in AD. Mounting preclinical and clinical evidence for a role of BuChE in maintaining normal cholinergic function and the pathology of AD provides a rationale for further studies investigating use of

Origin and late quaternary tectonism of a western Canadian continental shelf trough

NASA Astrophysics Data System (ADS)

Moslow, Thomas F.; Luternauer, John L.; Rohr, Kristin

1991-08-01

Analyses of high resolution and multi-channel seismic profiles from the central continental shelf of western Canada ascribe a late Quaternary glacial origin to large-scale troughs. Along the margins of Moresby Trough, one of three large-scale cross-shelf bathymetric depressions in Queen Charlotte Sound, seismic profiles within Quaternary sediments show a divergence of reflectors, thickening and folding of seismic units, and concavity of reflectors suggestive of drag. Compactional subsidence, growth faulting, and compaction faulting are also observed. Fault traces commonly terminate below the seabed. Deformation of Quaternary sediments due to faulting is plastic in nature and maximum offset of reflectors is 2.5 m. The observed Quaternary deformation appears to be a product of rapid deposition, loading and subsidence of late Quaternary sediment, which is unrelated to seismic activity. In addition, Quaternary faulting was probably activated by post-glacial loading and isostatic rebound of consolidated Tertiary strata along the margins of continental shelf troughs. The presence of mass movement (slump or debris flow) deposits overlying lithified Tertiary strata along the flanks of Moresby Trough provides the only evidence of seismic activity in the study area. The lack of a mud drape over these deposits implies a late Holocene age for the timing of their emplacement. The Quaternary troughs are incised into Tertiary-aged sedimentary fill of the Queen Charlotte basin. Previous workers had interpreted seafloor escarpments paralleling the trough margins to indicate that the location of Moresby Trough was controlled by renewed or continued activity on Tertiary-aged faults. A multi-channel seismic line across Moresby Trough shows that such an escarpment on the seafloor does not correlate to faults either in the Tertiary basin fill or the underlying basement. Tertiary reflectors are continuous underneath Moresby Trough; the seafloor escarpment is an erosional feature and was

Quaternary tectonic faulting in the Eastern United States

USGS Publications Warehouse

Wheeler, R.L.

2006-01-01

Paleoseismological study of geologic features thought to result from Quaternary tectonic faulting can characterize the frequencies and sizes of large prehistoric and historical earthquakes, thereby improving the accuracy and precision of seismic-hazard assessments. Greater accuracy and precision can reduce the likelihood of both underprotection and unnecessary design and construction costs. Published studies proposed Quaternary tectonic faulting at 31 faults, folds, seismic zones, and fields of earthquake-induced liquefaction phenomena in the Appalachian Mountains and Coastal Plain. Of the 31 features, seven are of known origin. Four of the seven have nontectonic origins and the other three features are liquefaction fields caused by moderate to large historical and Holocene earthquakes in coastal South Carolina, including Charleston; the Central Virginia Seismic Zone; and the Newbury, Massachusetts, area. However, the causal faults of the three liquefaction fields remain unclear. Charleston has the highest hazard because of large Holocene earthquakes in that area, but the hazard is highly uncertain because the earthquakes are uncertainly located. Of the 31 features, the remaining 24 are of uncertain origin. They require additional work before they can be clearly attributed either to Quaternary tectonic faulting or to nontectonic causes. Of these 24, 14 features, most of them faults, have little or no published geologic evidence of Quaternary tectonic faulting that could indicate the likely occurrence of earthquakes larger than those observed historically. Three more features of the 24 were suggested to have had Quaternary tectonic faulting, but paleoseismological and other studies of them found no evidence of large prehistoric earthquakes. The final seven features of uncertain origin require further examination because all seven are in or near urban areas. They are the Moodus Seismic Zone (Hartford, Connecticut), Dobbs Ferry fault zone and Mosholu fault (New York

Continuing Education in the Era of Quantum Change. 2003 ACHE Proceedings. (65th Annual Meeting, Charlottesville, VA, November 8-12, 2003)

ERIC Educational Resources Information Center

Barrineau, Irene T., Ed.

2003-01-01

This document presents the proceedings of the 2003 annual meeting of the Association for Continuing Higher Education (ACHE). These proceedings record the 65th Annual Meeting of ACHE held in Charlottesville, Virginia. President Allen Varner's theme for this annual meeting was, "Continuing Education in the Era of Quantum Change." The theme…

Viscosities of nonelectrolyte liquid mixtures. III. Selected binary and quaternary mixtures

NASA Astrophysics Data System (ADS)

Wakefield, D. L.

1988-05-01

This paper is the final in a series of three viscosity and density studies of pure n-alkanes and selected binary and quaternary mixtures. A standard U-tube viscometer was used for viscosity measurements, and a Pyrex flask-type pycnometer was used for density determinations. Results are given here for pure alkane and selected binary mixtures of n-tetradecane + n-octane, for selected quaternary mixtures of n-hexadecane + n-dodecane + n-decane + n-hexane, and for pure and selected quaternary mixtures of n-hexadecane + n-dodecane + n-nonane + n-heptane at 303.16 and 308.16 K. The principle of congruence was tested, as was the Grunberg and Nissan equation, as they have been shown to be useful as prediction techniques for other n-alkane binary mixtures. Comparisons were made between the two groups of quaternary alkane mixtures and the binary n-tetradecane + n-octane mixtures of the same “pseudo” composition to understand better the dependence of mixture viscosities on the composition parameter.

Evaluation of chitosan quaternary ammonium salt-modified resin denture base material.

PubMed

Song, Rong; Zhong, Zhaohua; Lin, Lexun

2016-04-01

Chitosan quaternary ammonium salt displays good antioxidant and antibacterial characteristics and it shows appreciable solubility in water. When added to the traditional denture material to form a resin base, it could promote good oral health by improving the oral environment. In this study, chitosan quaternary ammonium salt was added to the denture material following two different methods. After three months of immersion in artificial saliva, the specimens were tested for tensile strength and were scanned by electron microscope. The murine fibroblast cytotoxicity and antibacterial properties were also tested. The result showed no significant differences in the tensile strength and in the proliferation of murine L929 fibroblast cells. The two structures of chitosan quaternary ammonium salt-modified denture material had different degrees of corrosion resistance and antimicrobial properties. These results indicate that chitosan quaternary ammonium salt-modified resin denture base material has the potential to become a new generation oral denture composite material. Copyright © 2015 Elsevier B.V. All rights reserved.

Synthesis and Characterization of Perfluoro Quaternary Ammonium Anion Exchange Membranes

DTIC Science & Technology

2012-01-01

study, new alkaline exchange membranes were prepared from the perfluorinated 3M ionomer with various quaternary ammonium cations attached with...ammonium anion exchange membranes Report Title ABSTRACT In this study, new alkaline exchange membranes were prepared from the perfluorinated 3M ionomer...exchange membranes were prepared from the perfluorinated 3M ionomer with vari- ous quaternary ammonium cations attached with sulfonamide linkage. The

Tacripyrines, the first tacrine-dihydropyridine hybrids, as multitarget-directed ligands for the treatment of Alzheimer's disease.

PubMed

Marco-Contelles, José; León, Rafael; de los Ríos, Cristóbal; Samadi, Abdelouahid; Bartolini, Manuela; Andrisano, Vincenza; Huertas, Oscar; Barril, Xavier; Luque, F Javier; Rodríguez-Franco, María I; López, Beatriz; López, Manuela G; García, Antonio G; Carreiras, María do Carmo; Villarroya, Mercedes

2009-05-14

Tacripyrines (1-14) have been designed by combining an AChE inhibitor (tacrine) with a calcium antagonist such as nimodipine and are targeted to develop a multitarget therapeutic strategy to confront AD. Tacripyrines are selective and potent AChE inhibitors in the nanomolar range. The mixed type inhibition of hAChE activity of compound 11 (IC(50) 105 +/- 15 nM) is associated to a 30.7 +/- 8.6% inhibition of the proaggregating action of AChE on the Abeta and a moderate inhibition of Abeta self-aggregation (34.9 +/- 5.4%). Molecular modeling indicates that binding of compound 11 to the AChE PAS mainly involves the (R)-11 enantiomer, which also agrees with the noncompetitive inhibition mechanism exhibited by p-methoxytacripyrine 11. Tacripyrines are neuroprotective agents, show moderate Ca(2+) channel blocking effect, and cross the blood-brain barrier, emerging as lead candidates for treating AD.

Novel tetrahydrocarbazole benzyl pyridine hybrids as potent and selective butryl cholinesterase inhibitors with neuroprotective and β-secretase inhibition activities.

PubMed

Ghobadian, Roshanak; Mahdavi, Mohammad; Nadri, Hamid; Moradi, Alireza; Edraki, Najmeh; Akbarzadeh, Tahmineh; Sharifzadeh, Mohammad; Bukhari, Syed Nasir Abbas; Amini, Mohsen

2018-05-23

Butyrylcholinesterase (BuChE) inhibitors have become interesting target for treatment of Alzheimer's disease (AD). A series of dual binding site BuChE inhibitors were designed and synthesized based on 2,3,4,9-tetrahydro-1H-carbazole attached benzyl pyridine moieties. In-vitro assay revealed that all of the designed compounds were selective and potent BuChE inhibitors. The most potent BuChE inhibitor was compound 6i (IC 50  = 0.088 ± 0.0009 μM) with the mixed-type inhibition. Docking study revealed that 6i is a dual binding site BuChE inhibitor. Also, Pharmacokinetic properties for 6i were accurate to Lipinski's rule. In addition, compound 6i demonstrated neuroprotective and β-secretase (BACE1) inhibition activities. This compound could also inhibit AChE-induced and self-induced Aβ peptide aggregation at concentration of 100 μM and 10 μM respectively. Generally, the results are presented as new potent selective BuChE inhibitors with a therapeutic potential for the treatment of AD. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Cholinesterase inhibitors from Cleistocalyx operculatus buds.

PubMed

Min, Byung Sun; Cuong, To Dao; Lee, Joo-Sang; Shin, Beom-Soo; Woo, Mi Hee; Hung, Tran Manh

2010-10-01

Five flavonoids, myricetin-3'-methylether 3-O-β-D: -galactopyranoside (1), myricetin-3',5'-dimethylether 3-O-β-D: -galactopyranoside (2), quercetin (3), kaempferol (4), and tamarixetin (5) were isolated from the buds of Cleistocalyx operculatus (Myrtaceae). The chemical structures of these compounds were determined on the basis of spectroscopic analyses, including 2D NMR. Their anti-Alzheimer effects were evaluated via acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activity assays. All five compounds 1-5 showed potential inhibitory activities against AChE with IC(50) values of 19.9, 37.8, 25.9, 30.4 and 22.3 μM, respectively, while compounds 1, 3, 4 and 5 also possessed BChE inhibitory activity with IC(50) values of 152.5, 177.8, 62.5, and 160.6 μM, respectively.

Minimal erosion of Arctic alpine topography during late Quaternary glaciation

NASA Astrophysics Data System (ADS)

Gjermundsen, Endre F.; Briner, Jason P.; Akçar, Naki; Foros, Jørn; Kubik, Peter W.; Salvigsen, Otto; Hormes, Anne

2015-10-01

The alpine topography observed in many mountainous regions is thought to have formed during repeated glaciations of the Quaternary period. Before this time, landscapes had much less relief. However, the spatial patterns and rates of Quaternary exhumation at high latitudes--where cold-based glaciers may protect rather than erode landscapes--are not fully quantified. Here we determine the exposure and burial histories of rock samples from eight summits of steep alpine peaks in northwestern Svalbard (79.5° N) using analyses of 10Be and 26Al concentrations. We find that the summits have been preserved for at least the past one million years. The antiquity of Svalbard’s alpine landscape is supported by the preservation of sediments older than one million years along a fjord valley, which suggests that both mountain summits and low-elevation landscapes experienced very low erosion rates over the past million years. Our findings support the establishment of northwestern Svalbard’s alpine topography during the early Quaternary. We suggest that, as the Quaternary ice age progressed, glacial erosion in the Arctic became inefficient and confined to ice streams, and high-relief alpine landscapes were preserved by minimally erosive glacier armour.

The ichthyofauna of limnic systems in Quaternary deposits of extreme southern Brazil

PubMed Central

Assumpção, Cindy M.; Quintela, Fernando M.; Corrêa, Fabiano; Loebmann, Daniel

2016-01-01

Abstract The Quaternary in the state of Rio Grande do Sul (RS), southern Brazil, is geologically represented by the coastal plain and was originated by successive events of Pleistocene-Holocene marine transgressions and the occurrence of alluvial deposits. This paper aimed to characterize the fish assemblage occurring in a swampy Quaternary area adjacent to Lagoa Pequena, a lacustrine system connected to the west margin of the Laguna dos Patos estuary. A checklist is also provided of the ichthyofauna so far recorded in limnic systems of Quaternary deposits in the state of Rio Grande do Sul. A total of 42 species was recorded, distributed in nine orders, 18 families and 31 genera. Characidae and Cichlidae were the most representative families, comprising 15 and 4 species respectively. A bibliographic revision associated to our sample data revealed the occurrence of 156 species in limnic systems inserted in RS Quaternary deposits (114 limnic, 15 marine/estuarine/limnic, ten marine/estuarine, nine estuarine/limnic and eight marine). Characiformes and Siluriformes are the most diverse orders, corroborating the Neotropical pattern. Seven species can be considered endemic to RS Quaternary deposits. PMID:28174498

Quaternary extensional growth folding beneath Reno, Nevada, imaged by urban seismic profiling

USGS Publications Warehouse

Stephenson, William J.; Frary, Roxy N.; Louie, John; Odum, Jackson K.

2013-01-01

We characterize shallow subsurface faulting and basin structure along a transect through heavily urbanized Reno, Nevada, with high‐resolution seismic reflection imaging. The 6.8 km of P‐wave data image the subsurface to approximately 800 m depth and delineate two subbasins and basin uplift that are consistent with structure previously inferred from gravity modeling in this region of the northern Walker Lane. We interpret two primary faults that bound the uplift and deform Quaternary deposits. The dip of Quaternary and Tertiary strata in the western subbasin increases with greater depth to the east, suggesting recurrent fault motion across the westernmost of these faults. Deformation in the Quaternary section of the western subbasin is likely evidence of extensional growth folding at the edge of the Truckee River through Reno. This deformation is north of, and on trend with, previously mapped Quaternary fault strands of the Mt. Rose fault zone. In addition to corroborating the existence of previously inferred intrabasin structure, these data provide evidence for an active extensional Quaternary fault at a previously unknown location within the Truckee Meadows basin that furthers our understanding of both the seismotectonic framework and earthquake hazards in this urbanized region.

Aleksis Dreimanis: a legacy in Quaternary science

NASA Astrophysics Data System (ADS)

Hicock, Stephen R.; Menzies, John

2000-12-01

Aleksis Dreimanis was born and raised in Latvia. His interest in Quaternary and glacial geology began early and developed into a career that has spanned 7 decades. At age 20 he published his first paper in glacial geology and soon after began teaching at the University of Latvia. Teaching and research were interrupted by World War II but resumed at the Baltic University (Pinneberg, Germany), then at the University of Western Ontario where he has been ever since. Throughout his career, Dreimanis has successfully balanced the twin disciplines of Quaternary history and glacial geology. He was among the first to study quantitatively the relationship between till lithology and till formation and to study how glacial transport and dynamics affect till texture and deformation. With co-workers he developed the well-known stratigraphic scheme of the last glaciation in the Great Lakes region of North America. Aleksis became world-renowned through his committee work, especially as President of the INQUA Commission on Genesis and Lithology of Glacial Quaternary Deposits. His diplomacy, enthusiasm, and passion for his subject have inspired students and colleagues around the globe and resulted in remarkable international dialogue, cooperation, and consensus. Professor Aleksis Dreimanis is an honest scientist, a gentleman, and a true scholar who has left a rich legacy for future Quaternarists.

Acetylcholinesterase inhibition reveals endogenous nicotinic modulation of glutamate inputs to CA1 stratum radiatum interneurons in hippocampal slices

PubMed Central

Alkondon, Manickavasagom; Albuquerque, Edson X.; Pereira, Edna F.R.

2013-01-01

The involvement of brain nicotinic acetylcholine receptors (nAChRs) in the neurotoxicological effects of soman, a potent acetylcholinesterase (AChE) inhibitor and a chemical warfare agent, is not clear. This is partly due to a poor understanding of the role of AChE in brain nAChR-mediated functions. To test the hypothesis that AChE inhibition builds sufficient acetylcholine (ACh) in the brain and facilitates nAChR-dependent glutamate transmission, we used whole-cell patch-clamp technique to record spontaneous glutamate excitatory postsynaptic currents (EPSCs) from CA1 stratum radiatum interneurons (SRI) in hippocampal slices. First, the frequency, amplitude and kinetics of EPSCs recorded from slices of control guinea pigs were compared to those recorded from slices of guinea pigs after a single injection of the irreversible AChE inhibitor soman (25.2 μg/kg, s.c.). Second, EPSCs were recorded from rat hippocampal slices before and after their superfusion with the reversible AChE inhibitor donepezil (100 nM). The frequency of EPSCs was significantly higher in slices taken from guinea pigs 24 h but not 7 days after the soman injection than in slices from control animals. In 52% of the rat hippocampal slices tested, bath application of donepezil increased the frequency of EPSCs. Further, exposure to donepezil increased both burst-like and large-amplitude EPSCs, and increased the proportion of short (20–100 ms) inter-event intervals. Donepezil’s effects were suppressed significantly in presence of 10 μM mecamylamine or 10 nM methyllycaconitine. These results support the concept that AChE inhibition is able to recruit nAChR-dependent glutamate transmission in the hippocampus and such a mechanism can contribute to the acute neurotoxicological actions of soman. PMID:23511125

The nicotinic acetylcholine receptor: Binding of nitroxide analogs of a local anesthetic and a photoactivatable analog of phosphatidylserine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blanton, M.P.

1989-01-01

Electron spin resonance was used to contrast the accessibility of tertiary and quaternary amine local anesthetics to their high affinity binding site in the desensitized Torpedo californica acetylcholine receptor (AchR). Preincubation of AchR-rich membranes with agonist resulted in a substantial reduction in the initial association of the quaternary amine local anesthetic C6SLMEI with the receptor. The time-dependent reduction in association follows a biphasic exponential function having rate constants of 0.19 min{sup {minus}1} and 0.03 min{sup {minus}1}. In contrast, agonist preincubation did not produce a comparable decrease in the association of C6SL, a tertiary amine analog, with the AchR. The resultsmore » are modeled in two ways: (1) A charge gate near the channel mouth in the desensitized receptor limits access of the permanently charged cationic local anesthetic (C6SLMEI), but not for the uncharged form of the tertiary amine anesthetic C6SL. (2) A hydrophobic pathway, possibly through a corridor in the annular lipid surrounding receptor subunits, allows the uncharged form of C6SL to reach the high affinity binding site in the AchR. A photoactivatable analog of phosphatidylserine {sup 125}I 4-azido salicylic acid-phosphatidylserine ({sup 125}I ASA-PS) was use to label both Torpedo californica acetylcholine receptor-rich membranes and reconstituted AchR membranes. All four subunits of the AchR were found to incorporate label, with the {alpha} subunit incorporating approximately twice as much as each of the other subunits on a per mole basis. The regions of the AchR {alpha} subunit that incorporate {sup 125}I ASA-PS were mapped by Staphylococcus aureus V8 protease digestion. Eighty-one per cent of the incorporated label was localized to 11.7 and 10.1 kdal V8 cleavage fragments.« less

Atomic-scale properties of Ni-based FCC ternary, and quaternary alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tamm, Artur; Aabloo, Alvo; Klintenberg, Mattias

2015-08-26

The aim of our study is to characterize some atomic-scale properties of Ni-based FCC multicomponent alloys. For this purpose, we use Monte Carlo method combined with density functional theory calculations to study short-range order (SRO), atomic displacements, electronic density of states, and magnetic moments in equimolar ternary NiCrCo, and quaternary NiCrCoFe alloys. The salient features for the ternary alloy are a negative SRO parameter between Ni Cr and a positive between Cr Cr pairs as well as a weakly magnetic state. For the quaternary alloy we predict negative SRO parameter for Ni Cr and Ni Fe pairs and positive formore » Cr Cr and Fe Fe pairs. Atomic displacements for both ternary and quaternary alloys are negligible. In contrast to the ternary, the quaternary alloy shows a complex magnetic structure. The electronic structure of the ternary and quaternary alloys shows differences near the Fermi energy between a random solid solution and the predicted structure with SRO. Despite that, the calculated EXAFS spectra does not show enough contrast to discriminate between random and ordered structures. Finally, the predicted SRO has an impact on point-defect energetics, electron phonon coupling and thermodynamic functions and thus, SRO should not be neglected when studying properties of these two alloys.« less

2-Arylbenzofurans from Artocarpus lakoocha and methyl ether analogs with potent cholinesterase inhibitory activity.

PubMed

Namdaung, Umalee; Athipornchai, Anan; Khammee, Thongchai; Kuno, Mayuso; Suksamrarn, Sunit

2018-01-01

In vitro screening for acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities of the Artocarpus lakoocha root-bark extracts revealed interesting results. Bioassay-guided fractionation resulted in the isolation of two new (1 and 2) and six known 2-arylbenzofurans 3-8, along with one stilbenoid 9 and one flavonoid 10. The structures of the isolated compounds were elucidated by UV, IR, 1D- and 2D-NMR and MS spectroscopic data analysis. Compounds 4, 6 and 7 exhibited more potent AChE inhibitory activity (IC 50  = 0.87-1.10 μM) than the reference drug, galantamine. Compounds 4, 8 and 9 displayed greater BChE inhibition than the standard drug. The preferential inhibition of BChE over AChE indicated that 4 also showed a promising dual AChE and BChE inhibitor. The synthetic mono-methylated analogs 4a-c and 6a-b were found to be good BChE inhibitors with IC 50 values ranging between 0.31 and 1.11 μM. Based on the docking studies, compounds 4 and 6 are well-fitted in the catalytic triad of AChE. Compounds 4 and 6 showed different binding orientations on BChE, and the most potent BChE inhibitor 4 occupied dual binding to both CAS and PAS more efficiently. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Acetylcholinesterases of Blood-feeding Flies and Ticks

USDA-ARS?s Scientific Manuscript database

Acetylcholinesterase (AChE) is the biochemical target of organophosphate (OP) and carbamate pesticides for invertebrates, vertebrate nerve agents, and AChE inhibitors used to reduce effects of Alzheimer’s disease. Organophosphate pesticides (OPs) are widely used to control blood-feeding arthropods, ...

Microstructure of a-C:H films prepared on a microtrench and analysis of ions and radicals behavior

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hirata, Yuki; Choi, Junho, E-mail: choi@mech.t.u-tokyo.ac.jp

2015-08-28

Amorphous carbon films (a-C:H) were prepared on a microtrench (4-μm pitch and 4-μm depth), and the uniformity of film thickness and microstructure of the films on the top, sidewall, and bottom surfaces of the microtrench were evaluated by scanning electron microscopy and Raman spectroscopy. The a-C:H films were prepared by bipolar-type plasma based ion implantation and deposition (bipolar PBII&D), and the negative pulse voltage, which is the main parameter dominating the film structure, was changed from −1.0 to −15 kV. Moreover, the behavior of ions and radicals was analyzed simultaneously by combining the calculation methods of Particle-In-Cell/Monte Carlo Collision (PIC-MCC) andmore » Direct Simulation Monte Carlo (DSMC) to investigate the coating mechanism for the microtrench. The results reveal that the thickness uniformity of a-C:H films improves with decreasing negative pulse voltage due to the decreasing inertia of incoming ions from the trench mouth, although the film thickness on the sidewall tends to be much smaller than that on the top and bottom surfaces of the trench. The normalized flux and the film thickness show similar behavior, i.e., the normalized flux or thickness at the bottom surface increases at low negative pulse voltages and then saturates at a certain value, whereas at the sidewall it monotonically decreases with increasing negative voltage. The microstructure of a-C:H films on the sidewall surface is very different from that on the top and bottom surfaces. The film structure at a low negative pulse voltage shifts to more of a polymer-like carbon (PLC) structure due to the lower incident energy of ions. Although the radical flux on the sidewall increases slightly, the overall film structure is not significantly changed because this film formation at a low negative voltage is originally dominated by radicals. On the other hand, the flux of radicals is dominant on the sidewall in the case of high negative pulse voltage, resulting

Microstructure of a-C:H films prepared on a microtrench and analysis of ions and radicals behavior

NASA Astrophysics Data System (ADS)

Hirata, Yuki; Choi, Junho

2015-08-01

Amorphous carbon films (a-C:H) were prepared on a microtrench (4-μm pitch and 4-μm depth), and the uniformity of film thickness and microstructure of the films on the top, sidewall, and bottom surfaces of the microtrench were evaluated by scanning electron microscopy and Raman spectroscopy. The a-C:H films were prepared by bipolar-type plasma based ion implantation and deposition (bipolar PBII&D), and the negative pulse voltage, which is the main parameter dominating the film structure, was changed from -1.0 to -15 kV. Moreover, the behavior of ions and radicals was analyzed simultaneously by combining the calculation methods of Particle-In-Cell/Monte Carlo Collision (PIC-MCC) and Direct Simulation Monte Carlo (DSMC) to investigate the coating mechanism for the microtrench. The results reveal that the thickness uniformity of a-C:H films improves with decreasing negative pulse voltage due to the decreasing inertia of incoming ions from the trench mouth, although the film thickness on the sidewall tends to be much smaller than that on the top and bottom surfaces of the trench. The normalized flux and the film thickness show similar behavior, i.e., the normalized flux or thickness at the bottom surface increases at low negative pulse voltages and then saturates at a certain value, whereas at the sidewall it monotonically decreases with increasing negative voltage. The microstructure of a-C:H films on the sidewall surface is very different from that on the top and bottom surfaces. The film structure at a low negative pulse voltage shifts to more of a polymer-like carbon (PLC) structure due to the lower incident energy of ions. Although the radical flux on the sidewall increases slightly, the overall film structure is not significantly changed because this film formation at a low negative voltage is originally dominated by radicals. On the other hand, the flux of radicals is dominant on the sidewall in the case of high negative pulse voltage, resulting in a deviation

Effect of a nicotine vaccine on nicotine binding to the beta2-nAChRs in vivo in human tobacco smokers

PubMed Central

Esterlis, Irina; Hannestad, Jonas O.; Perkins, Evgenia; Bois, Frederic; D’Souza, D. Cyril; Tyndale, Rachel F.; Seibyl, John P.; Hatsukami, Dorothy M.; Cosgrove, Kelly P.; O’Malley, Stephanie S.

2013-01-01

Objective Nicotine acts in the brain to promote smoking in part by binding to the beta2-containing nicotinic acetylcholine receptors (β2*-nAChRs) and acting in the mesolimbic reward pathway. The effects of nicotine from smoking one tobacco cigarette are significant (80% of β2*-nAChRs occupied for >6h). This likely contributes to the maintenance of smoking dependence and low cessation outcomes. Development of nicotine vaccines provides potential for alternative treatments. We used [123I]5IA-85380 SPECT to evaluate the effect of 3′-AmNic-rEPA on the amount of nicotine that binds to the β2*-nAChRs in the cortical and subcortical regions in smokers. Method Eleven smokers (36years (SD=13); 19cig/day (SD=11) for 10years (SD=7) who were dependent on nicotine (Fagerström Test of Nicotine Dependence score =5.5 (SD=3); plasma nicotine 9.1 ng/mL (SD=5)) participated in 2 SPECT scan days: before and after immunization with 4–400μg doses of 3′-AmNic-rEPA. On SPECT scan days, 3 30-min baseline emission scans were obtained, followed by administration of IV nicotine (1.5mg/70kg) and up to 9 30-min emission scans. Results β2*-nAChR availability was quantified as VT/fP and nicotine binding was derived using the Lassen plot approach. Immunization led to a 12.5% reduction in nicotine binding (F=5.19, df=1,10, p=0.05). Significant positive correlations were observed between nicotine bound to β2*-nAChRs and nicotine injected before but not after vaccination (p=0.05 vs. p=0.98). There was a significant reduction in the daily number of cigarettes and desire for a cigarette (p=.01 and p=.04, respectively). Conclusions This proof-of-concept study demonstrates that immunization with nicotine vaccine can reduce the amount of nicotine binding to β2*-nAChRs and disrupt the relationship between nicotine administered vs. nicotine available to occupy β2*-nAChRs. PMID:23429725

Acetylcholinesterase complexed with bivalent ligands related to huperzine a: experimental evidence for species-dependent protein-ligand complementarity.

PubMed

Wong, Dawn M; Greenblatt, Harry M; Dvir, Hay; Carlier, Paul R; Han, Yi-Fan; Pang, Yuan-Ping; Silman, Israel; Sussman, Joel L

2003-01-15

Acetylcholinesterase (AChE) inhibitors improve the cognitive abilities of Alzheimer patients. (-)-Huperzine A [(-)-HupA], an alkaloid isolated from the club moss, Huperzia serrata, is one such inhibitor, but the search for more potent and selective drugs continues. Recently, alkylene-linked dimers of 5-amino-5,6,7,8-tetrahydroquinolinone (hupyridone, 1a), a fragment of HupA, were shown to serve as more potent inhibitors of AChE than (-)-HupA and monomeric 1a. We soaked two such dimers, (S,S)-(-)-bis(10)-hupyridone [(S,S)-(-)-2a] and (S,S)-(-)-bis(12)-hupyridone [(S,S)-(-)-2b] containing, respectively, 10 and 12 methylenes in the spacer, into trigonal TcAChE crystals, and solved the X-ray structures of the resulting complexes using the difference Fourier technique, both to 2.15 A resolution. The structures revealed one HupA-like 1a unit bound to the "anionic" subsite of the active-site, near the bottom of the active-site gorge, adjacent to Trp84, as seen for the TcAChE/(-)-HupA complex, and the second 1a unit near Trp279 in the "peripheral" anionic site at the top of the gorge, both bivalent molecules thus spanning the active-site gorge. The results confirm that the increased affinity of the dimeric HupA analogues for AChE is conferred by binding to the two "anionic" sites of the enzyme. Inhibition data show that (-)-2a binds to TcAChE approximately 6-7- and > 170-fold more tightly than (-)-2b and (-)-HupA, respectively. In contrast, previous data for rat AChE show that (-)-2b binds approximately 3- and approximately 2-fold more tightly than (-)-2a and (-)-HupA, respectively. Structural comparison of TcAChE with rat AChE, as represented by the closely related mouse AChE structure (1maa.pdb), reveals a narrower gorge for rat AChE, a perpendicular alignment of the Tyr337 ring to the gorge axis, and its conformational rigidity, as a result of hydrogen bonding between its hydroxyl group and that of Tyr341, relative to TcAChE Phe330. These structural differences in the

Proline-Based Carbamates as Cholinesterase Inhibitors.

PubMed

Pizova, Hana; Havelkova, Marketa; Stepankova, Sarka; Bak, Andrzej; Kauerova, Tereza; Kozik, Violetta; Oravec, Michal; Imramovsky, Ales; Kollar, Peter; Bobal, Pavel; Jampilek, Josef

2017-11-14

Series of twenty-five benzyl (2S)-2-(arylcarbamoyl)pyrrolidine-1-carboxylates was prepared and completely characterized. All the compounds were tested for their in vitro ability to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), and the selectivity of compounds to individual cholinesterases was determined. Screening of the cytotoxicity of all the compounds was performed using a human monocytic leukaemia THP-1 cell line, and the compounds demonstrated insignificant toxicity. All the compounds showed rather moderate inhibitory effect against AChE; benzyl (2 S )-2-[(2-chlorophenyl)carbamoyl]pyrrolidine-1-carboxylate (IC 50 = 46.35 μM) was the most potent agent. On the other hand, benzyl (2 S )-2-[(4-bromophenyl)-] and benzyl (2 S )-2-[(2-bromophenyl)carbamoyl]pyrrolidine-1-carboxylates expressed anti-BChE activity (IC 50 = 28.21 and 27.38 μM, respectively) comparable with that of rivastigmine. The ortho -brominated compound as well as benzyl (2 S )-2-[(2-hydroxyphenyl)carbamoyl]pyrrolidine-1-carboxylate demonstrated greater selectivity to BChE. The in silico characterization of the structure-inhibitory potency for the set of proline-based carbamates considering electronic, steric and lipophilic properties was provided using comparative molecular surface analysis (CoMSA) and principal component analysis (PCA). Moreover, the systematic space inspection with splitting data into the training/test subset was performed to monitor the statistical estimators performance in the effort to map the probability-guided pharmacophore pattern. The comprehensive screening of the AChE/BChE profile revealed potentially relevant structural and physicochemical features that might be essential for mapping of the carbamates inhibition efficiency indicating qualitative variations exerted on the reaction site by the substituent in the 3'-/4'-position of the phenyl ring. In addition, the investigation was completed by a molecular docking study of recombinant human AChE.

RAGE mediates the inactivation of nAChRs in sympathetic neurons under high glucose conditions.

PubMed

Chandna, Andrew R; Nair, Manoj; Chang, Christine; Pennington, Paul R; Yamamoto, Yasuhiko; Mousseau, Darrell D; Campanucci, Verónica A

2015-02-01

Autonomic dysfunction is a serious complication of diabetes and can lead to cardiovascular abnormalities and premature death. It was recently proposed that autonomic dysfunction is triggered by oxidation-mediated inactivation of neuronal nicotinic acetylcholine receptors (nAChRs), impairing synaptic transmission in sympathetic ganglia and resulting in autonomic failure. We investigated whether the receptor for advanced glycation end products (RAGE) and its role in the generation of reactive oxygen species (ROS) could be contributing to the events that initiate sympathetic malfunction under high glucose conditions. Using biochemical, live imaging and electrophysiological tools we demonstrated that exposure of sympathetic neurons to high glucose increases RAGE expression and oxidative markers, and that incubation with RAGE ligands (e.g. AGEs, S100 and HMGB1) mimics both ROS elevation and nAChR inactivation. In contrast, co-treatment with either antioxidants or an anti-RAGE IgG prevented the inactivation of nAChRs. Lastly, a role for RAGE in this context was corroborated by the lack of sensitivity of sympathetic neurons from RAGE knock-out mice to high glucose. These data define a pivotal role for RAGE in initiating the events associated with exposure of sympathetic neurons to high glucose, and strongly support RAGE signaling as a potential therapeutic target in the autonomic complications associated with diabetes. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

In Vitro and In Vivo Metabolism and Inhibitory Activities of Vasicine, a Potent Acetylcholinesterase and Butyrylcholinesterase Inhibitor

PubMed Central

Liu, Wei; Shi, Xiaoyuan; Yang, Yadi; Cheng, Xuemei; Liu, Qing; Han, Han; Yang, Baohua; He, Chunyong; Wang, Yongli; Jiang, Bo; Wang, Zhengtao; Wang, Changhong

2015-01-01

Vasicine (VAS), a potential natural cholinesterase inhibitor, exhibited promising anticholinesterase activity in preclinical models and has been in development for treatment of Alzheimer’s disease. This study systematically investigated the in vitro and in vivo metabolism of VAS in rat using ultra performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight mass spectrometry. A total of 72 metabolites were found based on a detailed analysis of their 1H- NMR and 13C NMR data. Six key metabolites were isolated from rat urine and elucidated as vasicinone, vasicinol, vasicinolone, 1,2,3,9-tetrahydropyrrolo [2,1-b] quinazolin-3-yl hydrogen sulfate, 9-oxo-1,2,3,9-tetrahydropyrrolo [2,1-b] quinazolin-3-yl hydrogen sulfate, and 1,2,3,9-tetrahydropyrrolo [2,1-b] quinazolin-3-β-D-glucuronide. The metabolic pathway of VAS in vivo and in vitro mainly involved monohydroxylation, dihydroxylation, trihydroxylation, oxidation, desaturation, sulfation, and glucuronidation. The main metabolic soft spots in the chemical structure of VAS were the 3-hydroxyl group and the C-9 site. All 72 metabolites were found in the urine sample, and 15, 25, 45, 18, and 11 metabolites were identified from rat feces, plasma, bile, rat liver microsomes, and rat primary hepatocyte incubations, respectively. Results indicated that renal clearance was the major excretion pathway of VAS. The acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities of VAS and its main metabolites were also evaluated. The results indicated that although most metabolites maintained potential inhibitory activity against AChE and BChE, but weaker than that of VAS. VAS undergoes metabolic inactivation process in vivo in respect to cholinesterase inhibitory activity. PMID:25849329

Recent Knowledge on Medicinal Plants as Source of Cholinesterase Inhibitors for the Treatment of Dementia.

PubMed

Tundis, Rosa; Bonesi, Marco; Menichini, Francesco; Loizzo, Monica R

2016-01-01

Dementia is becoming a major public health problem worldwide. The most common form of dementia is Alzheimer's disease (AD), characterized by a deficient cholinergic transmission, deposition of amyloid plaques and neurofibrillary tangles, and neuro-inflammation that result in progressive degeneration and/or death of nerve cells and cognitive impairment. At present, AD cannot be prevented or cured, so the symptomatic relief obtainable by the use of acetylcholinesterase (AChE) inhibitors is one of the therapeutic strategies. Accumulated evidence suggests that naturally occurring compounds may potentially improve memory and cognitive function, and prevent neurodegeneration. Even today the search for new neuroprotective agents of natural origin is very active. The neuroprotective effects of medicinal plants covering studies of the last years will be summarized and discussed in this review choosing a family classification with particular emphasis on extracts and isolated compounds as promising new drugs. The search of a multifunctional potential anti-AD agent able to act on different crucial targets, such as galanthamine, quercetin and timosaponin AIII, could be a useful approach to recognizing therapeutics against AD.

Quaternary extensional and compressional tectonics revealed from Quaternary landforms along Kosi River valley, outer Kumaun Lesser Himalaya, Uttarakhand

NASA Astrophysics Data System (ADS)

Luirei, Khayingshing; Bhakuni, S. S.; Kothyari, Girish Ch.; Tripathi, Kavita; Pant, P. D.

2016-04-01

A portion of the Kosi River in the outer Kumaun Lesser Himalaya is characterized by wide river course situated south of the Ramgarh Thrust, where huge thickness (~200 m) of the landslide deposits and two to three levels of unpaired fan terraces are present. Brittle normal faults, suggesting extensional tectonics, are recognized in the Quaternary deposits and bedrocks as further supported by surface morphology. Trending E-W, these faults measure from 3 to 5 km in length and are traced as discontinuous linear mini-horst and fault scarps (sackungen) exposed due to cutting across by streams. Active normal faults have displaced the coarsely laminated debris fan deposits at two sites located 550 m apart. At one of the sites, the faults look like bookshelf faulting with the maximum displacement of ~2 m and rotation of the Quaternary boulders along the fault plane is observed. At another site, the maximum displacement measures about 0.60 cm. Thick mud units deposited due to blocking of the streams by landslides are observed within and above the fan deposit. Landslide debris fans and terrace landforms are widely developed; the highest level of fan is observed ~1240 m above mean sea level. At some places, the reworking of the debris fans by streams is characterized by thick laminated sand body. Along the South Almora Thrust and Ramgarh Thrust zones, the valleys are narrow and V-shaped where Quaternary deposits are sparse due to relatively rapid uplift across these thrusts. Along the South Almora Thrust zone, three to four levels of fluvial terraces are observed and have been incised by river exposing the bedrocks due to recent movement along the RT and SAT. Abandoned channel, tilted mud deposits, incised meandering, deep-cut V-shaped valleys and strath terraces indicate rapid uplift of the area. Thick mud sequences in the Quaternary columns indicate damming of streams. A ~10-km-long north-south trending transverse Garampani Fault has offset the Ramgarh Thrust producing

An in vitro investigation of the effects of the nerve agent pretreatment pyridostigmine bromide on human peripheral blood T-cell function.

PubMed

Telford, Gary; Wilkinson, Lucy J; Hooi, Doreen S W; Worrall, Vivienne; Green, A Christopher; Cook, David L; Pritchard, David I; Griffiths, Gareth D

2004-11-01

The current pretreatment against nerve agent poisoning deployed by the UK and US armed forces is the acetylcholinesterase (EC 3.1.1.7) inhibitor pyridostigmine bromide (PB). At higher doses, PB is also used to treat the autoimmune disease myasthenia gravis. In both cases, the therapeutic effect is mediated by inhibition of acetylcholinesterase (AChE) at cholinergic synapses. However, the location of AChE is not restricted to these sites. AChE, acetylcholine (ACh) receptors and choline acetyltransferase have been reported to be expressed by T cells, suggesting that cholinergic signalling may exert some modulatory influence on T-cell function and consequently on the immune system. The aim of this study was to investigate the role of the T-cell cholinergic system in the immunological activation process and to examine whether inhibitors of AChE such as PB affect immune function. To investigate this, human peripheral blood mononuclear cells (PBMC) were stimulated using either mitogen, cross-linking of the T-cell receptor and co-receptors with antibodies (anti-CD3/CD28) or by antigen presentation in the presence of various AChE inhibitors and ACh receptor agonists or antagonist. Several indices were used to assess T-cell activation, including the secretion of IL-2, cell proliferation and expression of CD69. Treatment with PB had no significant effect on the immunological assays selected. Physostigmine (PHY), a carbamate compound similar to PB, consistently showed inhibition of T-cell activation, but only at concentrations in excess of those required to inhibit AChE. No evidence was found to support previously published findings showing muscarinic enhancement of cell proliferation or IL-2 secretion.

Database and Map of Quaternary Faults and Folds in Peru and its Offshore Region

USGS Publications Warehouse

Machare, Jose; Fenton, Clark H.; Machette, Michael N.; Lavenu, Alain; Costa, Carlos; Dart, Richard L.

2003-01-01

This publication consists of a main map of Quaternary faults and fiolds of Peru, a table of Quaternary fault data, a region inset map showing relative plate motion, and a second inset map of an enlarged area of interest in southern Peru. These maps and data compilation show evidence for activity of Quaternary faults and folds in Peru and its offshore regions of the Pacific Ocean. The maps show the locations, ages, and activity rates of major earthquake-related features such as faults and fault-related folds. These data are accompanied by text databases that describe these features and document current information on their activity in the Quaternary.

Design, synthesis and biological evaluation of benzo[e][1,2,4]triazin-7(1H)-one and [1,2,4]-triazino[5,6,1-jk]carbazol-6-one derivatives as dual inhibitors of beta-amyloid aggregation and acetyl/butyryl cholinesterase.

PubMed

Catto, Marco; Berezin, Andrey A; Lo Re, Daniele; Loizou, Georgia; Demetriades, Marina; De Stradis, Angelo; Campagna, Francesco; Koutentis, Panayiotis A; Carotti, Angelo

2012-12-01

Alzheimer's disease (AD) onset and progression are associated with the dysregulation of multiple and complex physiological processes and a successful therapeutic approach should therefore address more than one target. Two new chemical entities, the easily accessible heterocyclic scaffolds 1,3-diphenylbenzo[e][1,2,4]triazin-7(1H)-one (benzotriazinone I) and 2-phenyl-6H-[1,2,4]triazino[5,6,1-jk]carbazol-6-one (triazafluoranthenone II), were explored for their multitarget-directed inhibition of beta-amyloid (Aβ) fibrillization and acetyl- (AChE) and/or butyryl- (BChE) cholinesterase, three valuable targets for AD therapy. Introduction of appropriate amine substituents at positions 6 and 5 on scaffold I and II, respectively, allowed the preparation of a series of compounds that were tested as Aβ(1-40) aggregation and cholinesterase inhibitors. Potent inhibitors of Aβ self-aggregation were discovered and among them benzotriazinone 7 exhibited an outstanding IC(50) equal to 0.37 μM. Compounds bearing a basic amine linked to the heterocyclic scaffold through a linear alkyl chain of varying length also afforded good ChE inhibitors. In particular, benzotriazinone 24 and triazafluoranthenone 38 were endowed with an interesting multiple activity, the former displaying IC(50) values of 1.4, 1.5 and 1.9 μM on Aβ aggregation and AChE and BChE inhibition, respectively, and the latter showing IC(50) values of 1.4 and an outstanding 0.025 μM in the Aβ aggregation and BChE inhibition, respectively. Benzotriazinone 24 and triazafluoranthenone 29, selected owing to their suitable aqueous solubility and Aβ aggregation inhibition, were submitted to a time course kinetic assay followed with thioflavin T (ThT) spectrofluorimetry, circular dichroism (CD) and transmission electron microscopy (TEM). Experimental data indicated that 24 acted at a low concentration ratio (10 μM 24 vs. 50 μM Aβ), stabilizing the unstructured Aβ peptide and inhibiting fibrillogenesis, and that 29

Overexpression of acetylcholinesterase gene in rice results in enhancement of shoot gravitropism.

PubMed

Yamamoto, Kosuke; Shida, Satoshi; Honda, Yoshihiro; Shono, Mariko; Miyake, Hiroshi; Oguri, Suguru; Sakamoto, Hikaru; Momonoki, Yoshie S

2015-09-25

Acetylcholine (ACh), a known neurotransmitter in animals and acetylcholinesterase (AChE) exists widely in plants, although its role in plant signal transduction is unclear. We previously reported AChE in Zea mays L. might be related to gravitropism based on pharmacological study using an AChE inhibitor. Here we clearly demonstrate plant AChE play an important role as a positive regulator in the gravity response of plants based on a genetic study. First, the gene encoding a second component of the ACh-mediated signal transduction system, AChE was cloned from rice, Oryza sativa L. ssp. Japonica cv. Nipponbare. The rice AChE shared high homology with maize, siratro and Salicornia AChEs. Similar to animal and other plant AChEs, the rice AChE hydrolyzed acetylthiocholine and propionylthiocholine, but not butyrylthiocholine. Thus, the rice AChE might be characterized as an AChE (E.C.3.1.1.7). Similar to maize and siratro AChEs, the rice AChE exhibited low sensitivity to the AChE inhibitor, neostigmine bromide, compared with the electric eel AChE. Next, the functionality of rice AChE was proved by overexpression in rice plants. The rice AChE was localized in extracellular spaces of rice plants. Further, the rice AChE mRNA and its activity were mainly detected during early developmental stages (2 d-10 d after sowing). Finally, by comparing AChE up-regulated plants with wild-type, we found that AChE overexpression causes an enhanced gravitropic response. This result clearly suggests that the function of the rice AChE relate to positive regulation of gravitropic response in rice seedlings. Copyright © 2015 Elsevier Inc. All rights reserved.

Deformation and Quaternary Faulting in Southeast Missouri across the Commerce Geophysical Lineament

USGS Publications Warehouse

Stephenson, W.J.; Odum, J.K.; Williams, R.A.; Pratt, T.L.; Harrison, R.W.; Hoffman, D.

1999-01-01

High-resolution seismic-reflection data acquired at three sites along the surface projection of the Commerce geophysical lineament in southeast Missouri reveal a complex history of post-Cretaceous faulting that has continued into the Quaternary. Near Qulin, Missouri, approximately 20 m of apparent vertical fault displacement has occurred in the Quaternary. Reflection data collected at Idalia Hill, about 45 km to the northeast, reveal a series of reverse and possibly right-lateral strike-slip faults with Quaternary displacement. In the Benton Hills, 45 km northeast of Idalia Hill, seismic data image a complicated series of anticlinal and synclinal fault-bounded blocks immediately north of the Commerce fault. We infer that most of the deformation imaged in the upper 400 m of these three data sets occurred since post-Cretaceous time, and a significant portion of it occurred during Quaternary time. Collectively, these seismic data along with geomorphic and surface-geologic evidence suggest (1) the existence of at least one potential seismogenic structure in southeastern Missouri outside the main zones of New Madrid seismicity, and (2) these structures have been active during the Quaternary. The geographic location of the imaged deformation suggests it is related to structures along with the Commerce geophysical lineament.

Protein Flexibility Facilitates Quaternary Structure Assembly and Evolution

PubMed Central

Marsh, Joseph A.; Teichmann, Sarah A.

2014-01-01

The intrinsic flexibility of proteins allows them to undergo large conformational fluctuations in solution or upon interaction with other molecules. Proteins also commonly assemble into complexes with diverse quaternary structure arrangements. Here we investigate how the flexibility of individual protein chains influences the assembly and evolution of protein complexes. We find that flexibility appears to be particularly conducive to the formation of heterologous (i.e., asymmetric) intersubunit interfaces. This leads to a strong association between subunit flexibility and homomeric complexes with cyclic and asymmetric quaternary structure topologies. Similarly, we also observe that the more nonhomologous subunits that assemble together within a complex, the more flexible those subunits tend to be. Importantly, these findings suggest that subunit flexibility should be closely related to the evolutionary history of a complex. We confirm this by showing that evolutionarily more recent subunits are generally more flexible than evolutionarily older subunits. Finally, we investigate the very different explorations of quaternary structure space that have occurred in different evolutionary lineages. In particular, the increased flexibility of eukaryotic proteins appears to enable the assembly of heteromeric complexes with more unique components. PMID:24866000

Effective countermeasure against poisoning by organophosphorus insecticides and nerve agents.

PubMed

Albuquerque, Edson X; Pereira, Edna F R; Aracava, Yasco; Fawcett, William P; Oliveira, Maristela; Randall, William R; Hamilton, Tracey A; Kan, Robert K; Romano, James A; Adler, Michael

2006-08-29

The nerve agents soman, sarin, VX, and tabun are deadly organophosphorus (OP) compounds chemically related to OP insecticides. Most of their acute toxicity results from the irreversible inhibition of acetylcholinesterase (AChE), the enzyme that inactivates the neurotransmitter acetylcholine. The limitations of available therapies against OP poisoning are well recognized, and more effective antidotes are needed. Here, we demonstrate that galantamine, a reversible and centrally acting AChE inhibitor approved for treatment of mild to moderate Alzheimer's disease, protects guinea pigs from the acute toxicity of lethal doses of the nerve agents soman and sarin, and of paraoxon, the active metabolite of the insecticide parathion. In combination with atropine, a single dose of galantamine administered before or soon after acute exposure to lethal doses of soman, sarin, or paraoxon effectively and safely counteracted their toxicity. Doses of galantamine needed to protect guinea pigs fully against the lethality of OPs were well tolerated. In preventing the lethality of nerve agents, galantamine was far more effective than pyridostigmine, a peripherally acting AChE inhibitor, and it was less toxic than huperzine, a centrally acting AChE inhibitor. Thus, a galantamine-based therapy emerges as an effective and safe countermeasure against OP poisoning.

Effective countermeasure against poisoning by organophosphorus insecticides and nerve agents

PubMed Central

Albuquerque, Edson X.; Pereira, Edna F. R.; Aracava, Yasco; Fawcett, William P.; Oliveira, Maristela; Randall, William R.; Hamilton, Tracey A.; Kan, Robert K.; Romano, James A.; Adler, Michael

2006-01-01

The nerve agents soman, sarin, VX, and tabun are deadly organophosphorus (OP) compounds chemically related to OP insecticides. Most of their acute toxicity results from the irreversible inhibition of acetylcholinesterase (AChE), the enzyme that inactivates the neurotransmitter acetylcholine. The limitations of available therapies against OP poisoning are well recognized, and more effective antidotes are needed. Here, we demonstrate that galantamine, a reversible and centrally acting AChE inhibitor approved for treatment of mild to moderate Alzheimer’s disease, protects guinea pigs from the acute toxicity of lethal doses of the nerve agents soman and sarin, and of paraoxon, the active metabolite of the insecticide parathion. In combination with atropine, a single dose of galantamine administered before or soon after acute exposure to lethal doses of soman, sarin, or paraoxon effectively and safely counteracted their toxicity. Doses of galantamine needed to protect guinea pigs fully against the lethality of OPs were well tolerated. In preventing the lethality of nerve agents, galantamine was far more effective than pyridostigmine, a peripherally acting AChE inhibitor, and it was less toxic than huperzine, a centrally acting AChE inhibitor. Thus, a galantamine-based therapy emerges as an effective and safe countermeasure against OP poisoning. PMID:16914529

The role of Quaternary environmental change in plant macroevolution: the exception or the rule?

PubMed Central

Willis, Katherine J; Niklas, Karl J

2004-01-01

The Quaternary has been described as an important time for genetic diversification and speciation. This is based on the premise that Quaternary climatic conditions fostered the isolation of populations and, in some instances, allopatric speciation. However, the 'Quaternary Ice-Age speciation model' rests on two key assumptions: (i) that biotic responses to climate change during the Quaternary were significantly different from those of other periods in Earth's history; and (ii) that the mechanisms of isolation during the Quaternary were sufficient in time and space for genetic diversification to foster speciation. These assumptions are addressed by examining the plant fossil record for the Quaternary (in detail) and for the past 410 Myr, which encompasses previous intervals of icehouse Earth. Our examination of the Quaternary record indicates that floristic responses to climate changes during the past 1.8 Myr were complex and that a distinction has to be made between those plants that were able to withstand the extremes of glacial conditions and those that could not. Generation times are also important as are different growth forms (e.g. herbaceous annuals and arborescent perennials), resulting in different responses in terms of genetic divergence rates during isolation. Because of these variations in the duration of isolation of populations and genomic diversification rates, no canonical statement about the predominant floristic response to climatic changes during the Quaternary (i.e. elevated rates of speciation or extinction, or stasis) is currently possible. This is especially true because of a sampling bias in terms of the fossil record of tree species over that of species with non-arborescent growth forms. Nevertheless, based on the available information, it appears that the dominant response of arborescent species during the Quaternary was extinction rather than speciation or stasis. By contrast, our examination of the fossil record of vascular plants for the

Can quaternary ammonium methacrylates inhibit matrix MMPs and cathepsins?

PubMed Central

Tezvergil-Mutluay, Arzu; Agee, Kelli A.; Mazzoni, Annalisa; Carvalho, Ricardo M.; Carrilho, Marcela; Tersariol, Ivarne L.; Nascimento, Fabio D.; Imazato, Satoshi; Tjäderhane, Leo; Breschi, Lorenzo; Tay, Franklin R; Pashley, David H.

2014-01-01

Objective Dentin matrices release ICTP and CTX fragments during collagen degradation. ICTP fragments are known to be produced by MMPs. CTX fragments are thought to come from cathepsin K activity. The purpose of this study was to determine if quaternary methacrylates (QAMs) can inhibit matrix MMPs and cathepsins. Methods Dentin beams were demineralizated, and dried to constant weight. Beams were incubated with rh-cathepsin B, K, L or S for 24 h at pH 7.4 to identify which cathepsins release CTX at neutral pH. Beams were dipped in ATA, an antimicrobial QAM to determine if it can inhibit dentin matrix proteases. Other beams were dipped in another QAM (MDPB) to determine if it produced similar inhibition of dentin proteases. Results Only beams incubated with cathepsin K lost more dry mass than the controls and released CTX. Dentin beams dipped in ATA and incubated for 1 week at pH 7.4, showed a concentration-dependent reduction in weight-loss. There was no change in ICTP release from control values, meaning that ATA did not inhibit MMPs. Media concentrations of CTX fell significantly at 15 wt% ATA indicating that ATA inhibits capthesins. Beams dipped in increasing concentrations of MDPB lost progressively less mass, showing that MDPB is a protease-inhibitor. ICTP released from controls or beams exposed to low concentrations were the same, while 5 or 10% MDPB significantly lowered ICTP production. CTX levels were strongly inhibited by 2.5–10% MDPB, indicating that MDPB is a potent inhibitor of both MMPs and cathepsin K. Significance CTX seems to be released from dentin matrix only by cathepsin K. MMPs and cathepsin K and B may all contribute to matrix degradation. PMID:25467953

Recent Progress on the Stereoselective Synthesis of Cyclic Quaternary α-Amino Acids

PubMed Central

Cativiela, Carlos; Ordóñez, Mario

2010-01-01

The most recent papers describing the stereoselective synthesis of cyclic quaternary α-amino acids are collected in this review. The diverse synthetic approaches are classified according to the size of the ring and taking into account the bond that is formed to complete the quaternary skeleton. PMID:20300486

Binding free energy calculations to rationalize the interactions of huprines with acetylcholinesterase.

PubMed

Nascimento, Érica C M; Oliva, Mónica; Andrés, Juan

2018-05-01

In the present study, the binding free energy of a family of huprines with acetylcholinesterase (AChE) is calculated by means of the free energy perturbation method, based on hybrid quantum mechanics and molecular mechanics potentials. Binding free energy calculations and the analysis of the geometrical parameters highlight the importance of the stereochemistry of huprines in AChE inhibition. Binding isotope effects are calculated to unravel the interactions between ligands and the gorge of AChE. New chemical insights are provided to explain and rationalize the experimental results. A good correlation with the experimental data is found for a family of inhibitors with moderate differences in the enzyme affinity. The analysis of the geometrical parameters and interaction energy per residue reveals that Asp72, Glu199, and His440 contribute significantly to the network of interactions between active site residues, which stabilize the inhibitors in the gorge. It seems that a cooperative effect of the residues of the gorge determines the affinity of the enzyme for these inhibitors, where Asp72, Glu199, and His440 make a prominent contribution.

Binding free energy calculations to rationalize the interactions of huprines with acetylcholinesterase

NASA Astrophysics Data System (ADS)

Nascimento, Érica C. M.; Oliva, Mónica; Andrés, Juan

2018-03-01

In the present study, the binding free energy of a family of huprines with acetylcholinesterase (AChE) is calculated by means of the free energy perturbation method, based on hybrid quantum mechanics and molecular mechanics potentials. Binding free energy calculations and the analysis of the geometrical parameters highlight the importance of the stereochemistry of huprines in AChE inhibition. Binding isotope effects are calculated to unravel the interactions between ligands and the gorge of AChE. New chemical insights are provided to explain and rationalize the experimental results. A good correlation with the experimental data is found for a family of inhibitors with moderate differences in the enzyme affinity. The analysis of the geometrical parameters and interaction energy per residue reveals that Asp72, Glu199, and His440 contribute significantly to the network of interactions between active site residues, which stabilize the inhibitors in the gorge. It seems that a cooperative effect of the residues of the gorge determines the affinity of the enzyme for these inhibitors, where Asp72, Glu199, and His440 make a prominent contribution.

Binding free energy calculations to rationalize the interactions of huprines with acetylcholinesterase

NASA Astrophysics Data System (ADS)

Nascimento, Érica C. M.; Oliva, Mónica; Andrés, Juan

2018-05-01

In the present study, the binding free energy of a family of huprines with acetylcholinesterase (AChE) is calculated by means of the free energy perturbation method, based on hybrid quantum mechanics and molecular mechanics potentials. Binding free energy calculations and the analysis of the geometrical parameters highlight the importance of the stereochemistry of huprines in AChE inhibition. Binding isotope effects are calculated to unravel the interactions between ligands and the gorge of AChE. New chemical insights are provided to explain and rationalize the experimental results. A good correlation with the experimental data is found for a family of inhibitors with moderate differences in the enzyme affinity. The analysis of the geometrical parameters and interaction energy per residue reveals that Asp72, Glu199, and His440 contribute significantly to the network of interactions between active site residues, which stabilize the inhibitors in the gorge. It seems that a cooperative effect of the residues of the gorge determines the affinity of the enzyme for these inhibitors, where Asp72, Glu199, and His440 make a prominent contribution.

A benzothiazole/piperazine derivative with acetylcholinesterase inhibitory activity: Improvement in streptozotocin-induced cognitive deficits in rats.

PubMed

Demir Özkay, Ümide; Can, Özgür Devrim; Sağlık, Begüm Nurpelin; Turan, Nazlı

2017-12-01

Acetylcholinesterase (AChE) inhibitors are frequently prescribed to mitigate the cognitive decline in Alzheimer's disease. Thus, we investigated the possible efficacy of the AChE inhibitor 2-[(6-Nitro-2-benzothiazolyl)amino]-2-oxoethyl4-[2-(N,N-dimethylamino)ethyl] piperazine-1 carbodithioate (BPCT) in a streptozotocin (STZ)-induced Alzheimer's disease model (SADM). First, we analyzed the molecular interaction of BPCT with AChE via a docking study. Then, the cognitive effects of BPCT (10 and 20mg/kg) were evaluated in intracerebroventricular STZ- and vehicle-administered rats with the elevated plus maze (EPM), Morris water maze (MWM), and active avoidance (AA) tests. Locomotor activity was also assessed. Docking analysis indicated significant binding of BPCT to the AChE active site. In behavioral tests, STZ administration impaired cognitive performance in SADM rats versus control rats. Treatment with donepezil or BPCT significantly decreased the prolonged 2nd retention transfer latency and 2nd retention latency time values of the SADM group in the EPM and MWM tests, respectively. Further, prolonged latency times were decreased and reduced frequency of avoidance events were increased in the AA test. Locomotor activity between groups was not different. BPCT appears to function as a central AChE inhibitor, and its improvement of deficits in SADM rats suggests that it has therapeutic potential in Alzheimer's disease. Copyright © 2017 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

Electrical coupling and release of K+ from endothelial cells co-mediate ACh-induced smooth muscle hyperpolarization in guinea-pig inner ear artery

PubMed Central

Jiang, Zhi-Gen; Nuttall, Alfred L; Zhao, Hui; Dai, Chun-Fu; Guan, Bing-Cai; Si, Jun-Qiang; Yang, Yu-Qin

2005-01-01

The physiological basis of ACh-elicited hyperpolarization in guinea-pig in vitro cochlear spiral modiolar artery (SMA) was investigated by intracellular recording combined with dye labelling of recorded cells and immunocytochemistry. We found the following. (1) The ACh-hyperpolarization was prominent only in cells that had a low resting potential (less negative than −60 mV). ACh-hyperpolarization was reversibly blocked by 4-DAMP, charybdotoxin or BAPTA-AM, but not by Nω-nitro-l-arginine methyl ester, glipizide, indomethacin or 17-octadecynoic acid. (2) Ba2+ (100 μm) and ouabain (1 μm) each attenuated ACh-hyperpolarization by ∼ 30% in smooth muscle cells (SMCs) but had only slight or no inhibition in endothelial cells (ECs). A combination of Ba2+ and 18β-glycyrrhetinic acid near completely blocked the ACh-hyperpolarization in SMCs. (3) High K+ (10 mm) induced a smaller hyperpolarization in ECs than in SMCs, with an amplitude ratio of 0.49: 1. Ba2+ blocked the K+-induced hyperpolarization by ∼ 85% in both cell types, whereas ouabain inhibited K+-hyperpolarization differently in SMCs (19%) and ECs (35%) and increased input resistance. 18β-Glycyrrhetinic acid blocked the high K+-hyperpolarization in ECs only. (4) Weak myoendothelial dye coupling was detected by confocal microscopy in cells recorded with a propidium iodide-containing electrode for longer than 30 min. A sparse plexus of choline acetyltransferase-immunoreactive (ChAT) fibres was observed around the SMA and its up-stream arteries. (5) Evoked excitatory junction potentials (EJP) were partially blocked by 4-DAMP in half of the cells tested. We conclude that ACh-induced hyperpolarization originates from ECs via activation of Ca2+-activated potassium channels, and is independent of the release of NO, cyclo-oxygenase or cytochrome P450 products. ACh-induced hyperpolarization in smooth muscle cells involves two mechanisms: (a) electrical spread of the hyperpolarization from the endothelium, and (b

Electrical coupling and release of K+ from endothelial cells co-mediate ACh-induced smooth muscle hyperpolarization in guinea-pig inner ear artery.

PubMed

Jiang, Zhi-Gen; Nuttall, Alfred L; Zhao, Hui; Dai, Chun-Fu; Guan, Bing-Cai; Si, Jun-Qiang; Yang, Yu-Qin

2005-04-15

The physiological basis of ACh-elicited hyperpolarization in guinea-pig in vitro cochlear spiral modiolar artery (SMA) was investigated by intracellular recording combined with dye labelling of recorded cells and immunocytochemistry. We found the following. (1) The ACh-hyperpolarization was prominent only in cells that had a low resting potential (less negative than -60 mV). ACh-hyperpolarization was reversibly blocked by 4-DAMP, charybdotoxin or BAPTA-AM, but not by N(omega)-nitro-L-arginine methyl ester, glipizide, indomethacin or 17-octadecynoic acid. (2) Ba(2)(+) (100 microm) and ouabain (1 microm) each attenuated ACh-hyperpolarization by approximately 30% in smooth muscle cells (SMCs) but had only slight or no inhibition in endothelial cells (ECs). A combination of Ba(2)(+) and 18beta-glycyrrhetinic acid near completely blocked the ACh-hyperpolarization in SMCs. (3) High K(+) (10 mm) induced a smaller hyperpolarization in ECs than in SMCs, with an amplitude ratio of 0.49 : 1. Ba(2)(+) blocked the K(+)-induced hyperpolarization by approximately 85% in both cell types, whereas ouabain inhibited K(+)-hyperpolarization differently in SMCs (19%) and ECs (35%) and increased input resistance. 18beta-Glycyrrhetinic acid blocked the high K(+)-hyperpolarization in ECs only. (4) Weak myoendothelial dye coupling was detected by confocal microscopy in cells recorded with a propidium iodide-containing electrode for longer than 30 min. A sparse plexus of choline acetyltransferase-immunoreactive (ChAT) fibres was observed around the SMA and its up-stream arteries. (5) Evoked excitatory junction potentials (EJP) were partially blocked by 4-DAMP in half of the cells tested. We conclude that ACh-induced hyperpolarization originates from ECs via activation of Ca(2)(+)-activated potassium channels, and is independent of the release of NO, cyclo-oxygenase or cytochrome P450 products. ACh-induced hyperpolarization in smooth muscle cells involves two mechanisms: (a) electrical spread

Coumarins as cholinesterase inhibitors: A review.

PubMed

de Souza, Luana G; Rennã, Magdalena N; Figueroa-Villar, Jose D

2016-07-25

The first report in literature of the isolation of coumarin was in the year 1820. After this report, other papers were published demonstrating the isolation and synthesis of coumarin and analogues. These compounds have been studying along the years for several different pathologies. One of these pathologies was Alzheimer's disease (AD), being the main cause of dementia in the contemporary world. There are two hypotheses to explain the pathogenesis mechanism and disease symptoms, then having the "amyloid hypothesis" and the "cholinergic hypothesis". Some drugs for AD are based on the theory of "cholinergic hypothesis", which objective is to increase the concentration of ACh in the synaptic cleft by the inhibition of cholinesterases. Over the last twenty years, many studies with coumarins compounds were reported as cholinesterases inhibitors. The aim of the present review is to discuss the studies and development of new compounds for AD treatment. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

The non-competitive acetylcholinesterase inhibitor APS12-2 is a potent antagonist of skeletal muscle nicotinic acetylcholine receptors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grandič, Marjana; Aráoz, Romulo; Molgó, Jordi

APS12-2, a non-competitive acetylcholinesterase inhibitor, is one of the synthetic analogs of polymeric alkylpyridinium salts (poly-APS) isolated from the marine sponge Reniera sarai. In the present work the effects of APS12-2 were studied on isolated mouse phrenic nerve–hemidiaphragm muscle preparations, using twitch tension measurements and electrophysiological recordings. APS12-2 in a concentration-dependent manner blocked nerve-evoked isometric muscle contraction (IC{sub 50} = 0.74 μM), without affecting directly-elicited twitch tension up to 2.72 μM. The compound (0.007–3.40 μM) decreased the amplitude of miniature endplate potentials until a complete block by concentrations higher than 0.68 μM, without affecting their frequency. Full size endplate potentials,more » recorded after blocking voltage-gated muscle sodium channels, were inhibited by APS12-2 in a concentration-dependent manner (IC{sub 50} = 0.36 μM) without significant change in the resting membrane potential of the muscle fibers up to 3.40 μM. The compound also blocked acetylcholine-evoked inward currents in Xenopus oocytes in which Torpedo (α1{sub 2}β1γδ) muscle-type nicotinic acetylcholine receptors (nAChRs) have been incorporated (IC{sub 50} = 0.0005 μM), indicating a higher affinity of the compound for Torpedo (α1{sub 2}β1γδ) than for the mouse (α1{sub 2}β1γε) nAChR. Our data show for the first time that APS12-2 blocks neuromuscular transmission by a non-depolarizing mechanism through an action on postsynaptic nAChRs of the skeletal neuromuscular junction. -- Highlights: ► APS12-2 produces concentration-dependent inhibition of nerve-evoked muscle contraction in vitro. ► APS12-2 blocks MEPPs and EPPs at the neuromuscular junction. APS12-2 blocks ACh-activated current in Xenopus oocytes incorporated with Torpedo nAChRs.« less

Algicidal Activity of a Surface-Bonded Organosilicon Quaternary Ammonium Chloride

PubMed Central

Walters, P. A.; Abbott, E. A.; Isquith, A. J.

1973-01-01

The hydrolysis product of a quaternary amine-containing organosilicon salt, 3-(trimethoxysilyl)-propyldimethyloctadecyl ammonium chloride, was found to exhibit algicidal activity while chemically bonded to a variety of substrates. Six representative species of Chlorophyta, Cyanophyta, and Chrysophyta were used to evaluate the algicidal activity. Substrate-bonded 14C-labeled organosilicon quaternary ammonium salt when attached to nonwoven fibers was durable to repeated washings, and algicidal activity could not be attributed to slow release of the chemical. Images PMID:4632852

Foccα6, a truncated nAChR subunit, positively correlates with spinosad resistance in the western flower thrips, Frankliniella occidentalis (Pergande).

PubMed

Wan, Yanran; Yuan, Guangdi; He, Bingqing; Xu, Baoyun; Xie, Wen; Wang, Shaoli; Zhang, Youjun; Wu, Qingjun; Zhou, Xuguo

2018-08-01

Nicotinic acetylcholine receptors (nAChRs), a molecular target for spinosyns and neonicotinoids, mediate rapid cholinergic transmission in insect central nervous system by binding acetylcholine. Previous studies have shown that mutations in nAChRs contribute to the high level of resistance to these two classes of insecticides. In this study, we identified nine nAChR subunits from a transcriptome of the western flower thrips, Frankliniella occidentalis, including α1-7, β1, and β2. Exon 4 of α4 and exons 3 and 8 of α6 each have two splicing variants, respectively. In addition, altered or incorrect splicing leads to truncated forms of α3, α5, and α6 subunits. The abundance of every nAChRs in both spinosad susceptible and resistant strains was highest in the 1st instar nymph. Significantly more truncated forms of α6 subunit were detected in spinosad resistant strains, whereas, hardly any full-length form was found in the two highly resistant F. occidentalis strains (resistance ratio >10 4 -fold). Under laboratory conditions, spinosad resistance was positively correlated with truncated α6 transcripts. The correlation was later confirmed under the field conditions using five field strains. As the molecular target of spinosad, the percentage of truncated nAChR α6 subunits can be used as a diagnostic tool to detect and quantify spinosad resistance in the field. Copyright © 2018. Published by Elsevier Ltd.

Quaternary vertebrate faunas from Sumba, Indonesia: implications for Wallacean biogeography and evolution

PubMed Central

Crees, Jennifer J.; Hansford, James; Jeffree, Timothy E.; Crumpton, Nick; Kurniawan, Iwan; Setiyabudi, Erick; Paranggarimu, Umbu; Dosseto, Anthony; van den Bergh, Gerrit D.

2017-01-01

Historical patterns of diversity, biogeography and faunal turnover remain poorly understood for Wallacea, the biologically and geologically complex island region between the Asian and Australian continental shelves. A distinctive Quaternary vertebrate fauna containing the small-bodied hominin Homo floresiensis, pygmy Stegodon proboscideans, varanids and giant murids has been described from Flores, but Quaternary faunas are poorly known from most other Lesser Sunda Islands. We report the discovery of extensive new fossil vertebrate collections from Pleistocene and Holocene deposits on Sumba, a large Wallacean island situated less than 50 km south of Flores. A fossil assemblage recovered from a Pleistocene deposit at Lewapaku in the interior highlands of Sumba, which may be close to 1 million years old, contains a series of skeletal elements of a very small Stegodon referable to S. sumbaensis, a tooth attributable to Varanus komodoensis, and fragmentary remains of unidentified giant murids. Holocene cave deposits at Mahaniwa dated to approximately 2000–3500 BP yielded extensive material of two new genera of endemic large-bodied murids, as well as fossils of an extinct frugivorous varanid. This new baseline for reconstructing Wallacean faunal histories reveals that Sumba's Quaternary vertebrate fauna, although phylogenetically distinctive, was comparable in diversity and composition to the Quaternary fauna of Flores, suggesting that similar assemblages may have characterized Quaternary terrestrial ecosystems on many or all of the larger Lesser Sunda Islands. PMID:28855367

Selective acetyl- and butyrylcholinesterase inhibitors reduce amyloid-β ex vivo activation of peripheral chemo-cytokines from Alzheimer’s disease subjects: exploring the cholinergic anti-inflammatory pathway

PubMed Central

Reale, Marcella; Di Nicola, Marta; Velluto, Lucia; D’Angelo, Chiara; Costantini, Erica; Lahiri, Debomoy K.; Kamal, Mohammad A.; Yu, Qian-sheng; Greig, Nigel H.

2016-01-01

Increasing evidence suggests that the early pathogenesis of Alzheimer’s disease (AD) is driven by elevated production and/or reduced clearance of amyloid-β peptide (Aβ), which is derived from the larger Aβ precursor protein (APP). Aβ aggregates to form neurotoxic soluble oligomers that trigger a cascade of events leading to neuronal dysfunction, neurodegeneration and, ultimately, clinical dementia. Inflammation, both within the brain and systemically, together with a deficiency in the brain neurotransmitter acetylcholine, which underpinned the development of anticholinesterases for the symptomatic treatment of AD, are invariable hallmarks of the disease. The inter-relation between Aβ, inflammation and cholinergic signaling is complex, with each feeding back onto the others to drive disease progression. To elucidate these interactions plasma samples and peripheral blood mononuclear cells (PBMCs) were evaluated from healthy control (HC) subjects and AD patients. Plasma levels of acetyl- (AChE) and butyrylcholinesterase (BuChE) as well as Aβ were significantly elevated in AD vs. HC subjects, and acetylcholine showed a trend towards reduced levels. Aβ challenge of the AD and HC PBMCs resulted in greater release of inflammatory cytokines interleukin-1β (IL-1β), monocyte chemotactic protein-1 (MCP-1) and tumor necrosis factor-alpha (TNF-α) from AD vs. HC subjects, with IL-10 expression being similarly affected. THP-1 monocytic cells, a cell culture counterpart of PBMCs and brain microglial cells, responded similarly to Aβ as well as to phytohaemagglutinin (PHA) challenge, to allow preliminary analysis of the cellular and molecular pathways that underpin Aβ-induced changes in cytokine expression. In light of prior studies demonstrating that APP expression was regulated by specific cytokines and anticholinesterase drugs, the latter were evaluated on Aβ- and PHA-induced chemo-cytokine expression. Co-incubation with selective inhibitors, such as the

Clinical Significance of Repetitive Compound Muscle Action Potentials in Patients with Myasthenia Gravis: A Predictor for Cholinergic Side Effects of Acetylcholinesterase Inhibitors

PubMed Central

Lee, Hyo Eun; Kim, Yool-hee; Kim, Seung Min

2016-01-01

Background and Purpose Acetylcholinesterase inhibitors (AChEIs) are widely used to treat myasthenia gravis (MG). Although AChEIs are usually tolerated well, some MG patients suffer from side effects. Furthermore, a small proportion of MG patients show cholinergic hypersensitivity and cannot tolerate AChEIs. Because repetitive compound muscle action potentials (R-CMAPs) are an electrophysiologic feature of cholinergic neuromuscular hyperactivity, we investigated the clinical characteristics of MG patients with R-CMAPs to identify their clinical usefulness in therapeutic decision-making. Methods We retrospectively reviewed the clinical records and electrodiagnostic findings of MG patients who underwent electrodiagnostic studies and diagnostic neostigmine testing (NT). Results Among 71 MG patients, 9 could not tolerate oral pyridostigmine bromide (PB) and 17 experienced side effects of PB. R-CMAPs developed in 24 patients after NT. The highest daily dose of PB was lower in the patients with R-CMAPs (240 mg/day vs. 480 mg/day, p<0.001). The frequencies of PB intolerance and side effects were higher in the patients with R-CMAPs than in those without R-CMAPs [37.5% vs. 0% (p<0.001) and 45.8% vs. 12.8% (p=0.002), respectively]. The MG Foundation of America postintervention status did not differ significantly between MG patients with and without R-CMAPs, and the response to immunotherapy was also good in both groups. Conclusions Side effects of and intolerance to AChEIs are more common in MG patients with R-CMAPs than in those without R-CMAPs. AChEIs should be used carefully in MG patients with R-CMAPs. The presence of R-CMAPs after NT may be a good indicator of the risks of PB side effects and intolerance. PMID:27819419

Cigarette smoking during pregnancy regulates the expression of specific nicotinic acetylcholine receptor (nAChR) subunits in the human placenta

DOE Office of Scientific and Technical Information (OSTI.GOV)

Machaalani, R., E-mail: rita.machaalani@sydney.edu.au; Bosch Institute, The University of Sydney, NSW 2006; The Children's Hospital at Westmead, NSW 2145

Smoking during pregnancy is associated with low birth weight, premature delivery, and neonatal morbidity and mortality. Nicotine, a major pathogenic compound of cigarette smoke, binds to the nicotinic acetylcholine receptors (nAChRs). A total of 16 nAChR subunits have been identified in mammals (9 α, 4 β, and 1 δ, γ and ε subunits). The effect of cigarette smoking on the expression of these subunits in the placenta has not yet been determined, thus constituting the aim of this study. Using RT-qPCR and western blotting, this study investigated all 16 mammalian nAChR subunits in the normal healthy human placenta, and comparedmore » mRNA and protein expressions in the placentas from smokers (n = 8) to controls (n = 8). Our data show that all 16 subunit mRNAs are expressed in the normal, non-diseased human placenta and that the expression of α2, α3, α4, α9, β2 and β4 subunits is greater than the other subunits. For mRNA, cigarette smoke exposure was associated with increased expression of the α9 subunit, and decreased expression of the δ subunit. At the protein level, expression of both α9 and δ was increased. Thus, cigarette smoking in pregnancy is sufficient to regulate nAChR subunits in the placenta, specifically α9 and δ subunits, and could contribute to the adverse effects of vasoconstriction and decreased re-epithelialisation (α9), and increased calcification and apoptosis (δ), seen in the placentas of smoking women. - Highlights: • All 16 mammalian nAChR subunits are expressed in the human placenta. • Cigarette smoking increases α9 mRNA and protein in the placenta. • Cigarette smoking decreases δ mRNA but increases δ protein in the placenta.« less

OMVPE Growth of Quaternary (Al,Ga,In)N for UV Optoelectronics (title change from A)

DOE Office of Scientific and Technical Information (OSTI.GOV)

HAN,JUNG; FIGIEL,JEFFREY J.; PETERSEN,GARY A.

We report the growth and characterization of quaternary AlGaInN. A combination of photoluminescence (PL), high-resolution x-ray diffraction (XRD), and Rutherford backscattering spectrometry (RBS) characterizations enables us to explore the contours of constant PL peak energy and lattice parameter as functions of the quaternary compositions. The observation of room temperature PL emission at 351nm (with 20% Al and 5% In) renders initial evidence that the quaternary could be used to provide confinement for GaInN (and possibly GaN). AlGaInN/GrdnN MQW heterostructures have been grown; both XRD and PL measurements suggest the possibility of incorporating this quaternary into optoelectronic devices.

Differential efficacy of treatment with acetylcholinesterase inhibitors in patients with mild and moderate Alzheimer's disease over a 6-month period.

PubMed

López-Pousa, S; Turon-Estrada, A; Garre-Olmo, J; Pericot-Nierga, I; Lozano-Gallego, M; Vilalta-Franch, M; Hernández-Ferràndiz, M; Morante-Muñoz, V; Isern-Vila, A; Gelada-Batlle, E; Majó-Llopart, J

2005-01-01

There are various anticholinesterase inhibitors (AChEIs) for the symptomatic treatment of mild to moderate Alzheimer's disease (AD). All AChEIs have shown greater efficacy than placebo in randomized, double-blind, parallel-group clinical trials. No differential studies have yet been made of the efficacy between all AChEIs. The study aims to determine the differential efficacy of the AChEIs with respect to a historical sample of patients with AD that were not treated with AChEIs. An open-label, prospective, observational study with a retrospective control group was undertaken to examine the evolution of the cognitive function over a 6-month period. The patients were assessed with the Mini-Mental State Examination (MMSE) at study entry and at 6 months. A general linear model was applied for repeated measurements with the MMSE score as the dependent variable, treatment type as an independent variable and the severity of the deterioration, age and the MMSE baseline score as covariables. Of the sample of 147 patients, 40 initiated treatment with donepezil, 32 with galantamine, 30 with rivastigmine and 45 were part of a historical sample of the memory clinic patients between 1991 and 1996 that had not been treated with AChEIs. The average age was 73.7 years (SD = 6.9; range = 52-86), 67.3% were women, 78.2% of the cases were mild and the MMSE baseline score was 18.1 points (range = 11-27). No significant intergroup differences were observed in these variables. The average doses of donepezil, galantamine and rivastigmine were 5.87 mg/day (SD = 1.92), 14.81 mg/day (SD = 6.25) and 6.41 mg/day (SD = 1.82), respectively. At 6 months, the difference in the MMSE score with respect to the untreated group was 1.6 points for donepezil (95% CI 0.79-2.37; p < 0.001), 0.99 points for galantamine (95% CI 0.14-1.85; p = 0.01) and 0.90 points for rivastigmine (95% CI 0.05-1.74; p = 0.03). No significant differences were observed in the efficacy among the groups treated with AChEIs (p

Repeated administration of an acetylcholinesterase inhibitor attenuates nicotine taking in rats and smoking behavior in human smokers

PubMed Central

Ashare, R L; Kimmey, B A; Rupprecht, L E; Bowers, M E; Hayes, M R; Schmidt, H D

2016-01-01

Tobacco smoking remains the leading cause of preventable death worldwide and current smoking cessation medications have limited efficacy. Thus, there is a clear need for translational research focused on identifying novel pharmacotherapies for nicotine addiction. Our previous studies demonstrated that acute administration of an acetylcholinesterase inhibitor (AChEI) attenuates nicotine taking and seeking in rats and suggest that AChEIs could be repurposed for smoking cessation. Here, we expand upon these findings with experiments designed to determine the effects of repeated AChEI administration on voluntary nicotine taking in rats as well as smoking behavior in human smokers. Rats were trained to self-administer intravenous infusions of nicotine (0.03 mg kg−1 per 0.59 ml) on a fixed-ratio-5 schedule of reinforcement. Once rats maintained stable nicotine taking, galantamine or donepezil was administered before 10 consecutive daily nicotine self-administration sessions. Repeated administration of 5.0 mg kg−1 galantamine and 3.0 mg kg−1 donepezil attenuated nicotine self-administration in rats. These effects were reinforcer-specific and not due to adverse malaise-like effects of drug treatment as repeated galantamine and donepezil administration had no effects on sucrose self-administration, ad libitum food intake and pica. The effects of repeated galantamine (versus placebo) on cigarette smoking were also tested in human treatment-seeking smokers. Two weeks of daily galantamine treatment (8.0 mg (week 1) and 16.0 mg (week 2)) significantly reduced smoking rate as well as smoking satisfaction and reward compared with placebo. This translational study indicates that repeated AChEI administration reduces nicotine reinforcement in rats and smoking behavior in humans at doses not associated with tolerance and/or adverse effects. PMID:26784967

Ecological impacts of the late Quaternary megaherbivore extinctions.

PubMed

Gill, Jacquelyn L

2014-03-01

As a result of the late Quaternary megafaunal extinctions (50,000-10,000 before present (BP)), most continents today are depauperate of megaherbivores. These extinctions were time-transgressive, size- and taxonomically selective, and were caused by climate change, human hunting, or both. The surviving megaherbivores often act as ecological keystones, which was likely true in the past. In spite of this and extensive research on the causes of the Late Quaternary Extinctions, the long-term ecological consequences of the loss of the Pleistocene megafauna remained unknown until recently, due to difficulties in linking changes in flora and fauna in paleorecords. The quantification of Sporormiella and other dung fungi have recently allowed for explicit tests of the ecological consequences of megafaunal extirpations in the fossil pollen record. In this paper, I review the impacts of the loss of keystone megaherbivores on vegetation in several paleorecords. A growing number of studies support the hypothesis that the loss of the Pleistocene megafauna resulted in cascading effects on plant community composition, vegetation structure and ecosystem function, including increased fire activity, novel communities and shifts in biomes. Holocene biota thus exist outside the broader evolutionary context of the Cenozoic, and the Late Quaternary Extinctions represent a regime shift for surviving plant and animal species.