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Environmental Health Perspectives Apr 2021Inhibition of acetylcholinesterase (AChE), a biomarker of organophosphorous and carbamate exposure in environmental and occupational human health, has been commonly used...
BACKGROUND
Inhibition of acetylcholinesterase (AChE), a biomarker of organophosphorous and carbamate exposure in environmental and occupational human health, has been commonly used to identify potential safety liabilities. So far, many environmental chemicals, including drug candidates, food additives, and industrial chemicals, have not been thoroughly evaluated for their inhibitory effects on AChE activity. AChE inhibitors can have therapeutic applications (e.g., tacrine and donepezil) or neurotoxic consequences (e.g., insecticides and nerve agents).
OBJECTIVES
The objective of the current study was to identify environmental chemicals that inhibit AChE activity using and models.
METHODS
To identify AChE inhibitors rapidly and efficiently, we have screened the Toxicology in the 21st Century (Tox21) 10K compound library in a quantitative high-throughput screening (qHTS) platform by using the homogenous cell-based AChE inhibition assay and enzyme-based AChE inhibition assays (with or without microsomes). AChE inhibitors identified from the primary screening were further tested in monolayer or spheroid formed by SH-SY5Y and neural stem cell models. The inhibition and binding modes of these identified compounds were studied with time-dependent enzyme-based AChE inhibition assay and molecular docking, respectively.
RESULTS
A group of known AChE inhibitors, such as donepezil, ambenonium dichloride, and tacrine hydrochloride, as well as many previously unreported AChE inhibitors, such as chelerythrine chloride and cilostazol, were identified in this study. Many of these compounds, such as pyrazophos, phosalone, and triazophos, needed metabolic activation. This study identified both reversible (e.g., donepezil and tacrine) and irreversible inhibitors (e.g., chlorpyrifos and bromophos-ethyl). Molecular docking analyses were performed to explain the relative inhibitory potency of selected compounds.
CONCLUSIONS
Our tiered qHTS approach allowed us to generate a robust and reliable data set to evaluate large sets of environmental compounds for their AChE inhibitory activity. https://doi.org/10.1289/EHP6993.
Topics: Acetylcholinesterase; Cholinesterase Inhibitors; Humans; Insecticides; Molecular Docking Simulation
PubMed: 33844597
DOI: 10.1289/EHP6993 -
British Journal of Pharmacology and... Feb 1963A close correlation has been shown to exist between the in vitro anticholinesterase potencies of ambenonium, neostigmine, methoxyambenonium and edrophonium chloride and...
A close correlation has been shown to exist between the in vitro anticholinesterase potencies of ambenonium, neostigmine, methoxyambenonium and edrophonium chloride and their abilities to increase muscle contractions produced by close-arterial injections of acetylcholine. No correlation was found between the anticholinesterase potencies of the drugs and their potentiations of the maximal twitch in response to electrical stimulation, or their antagonisms of tubocurarine. It is concluded that some action, in addition to inhibition of cholinesterase, contributed to their facilitation at the neuromuscular junction, and it is suggested that this action may be at the prejunctional site.
Topics: Acetylcholine; Ambenonium Chloride; Cholinesterase Inhibitors; Cholinesterases; Edrophonium; Electric Stimulation; Muscle Contraction; Neostigmine; Neuromuscular Junction; Neuromuscular Nondepolarizing Agents; Parasympathomimetics; Synaptic Transmission; Tubocurarine
PubMed: 13971349
DOI: 10.1111/j.1476-5381.1963.tb01297.x -
Neural Plasticity 2015Chronic pain is a major health issue and most patients suffer from spontaneous pain. Previous studies suggest that Huperzine A (Hup A), an alkaloid isolated from the...
Chronic pain is a major health issue and most patients suffer from spontaneous pain. Previous studies suggest that Huperzine A (Hup A), an alkaloid isolated from the Chinese herb Huperzia serrata, is a potent analgesic with few side effects. However, whether it alleviates spontaneous pain is unclear. We evaluated the effects of Hup A on spontaneous pain in mice using the conditioned place preference (CPP) behavioral assay and found that application of Hup A attenuated the mechanical allodynia induced by peripheral nerve injury or inflammation. This effect was blocked by atropine. However, clonidine but not Hup A induced preference for the drug-paired chamber in CPP. The same effects occurred when Hup A was infused into the anterior cingulate cortex. Furthermore, ambenonium chloride, a competitive inhibitor of acetylcholinesterase, also increased the paw-withdrawal threshold but failed to induce place preference in CPP. Therefore, our data suggest that acetylcholinesterase in both the peripheral and central nervous systems is involved in the regulation of mechanical allodynia but not the spontaneous pain.
Topics: Acetylcholinesterase; Alkaloids; Ambenonium Chloride; Analgesics; Animals; Atropine; Behavior, Animal; Cholinesterase Inhibitors; Chronic Pain; Clonidine; Gyrus Cinguli; Hyperalgesia; Inflammation; Learning; Lipopolysaccharides; Male; Mice; Mice, Inbred C57BL; Muscarinic Antagonists; Neuralgia; Pain Threshold; Peroneal Nerve; Receptors, Muscarinic; Sesquiterpenes
PubMed: 26697233
DOI: 10.1155/2015/453170 -
Neuron Aug 2016Cholinergic interneurons (CHIs) play a major role in motor and learning functions of the striatum. As acetylcholine does not directly evoke postsynaptic events at most...
Cholinergic interneurons (CHIs) play a major role in motor and learning functions of the striatum. As acetylcholine does not directly evoke postsynaptic events at most striatal synapses, it remains unclear how postsynaptic cholinergic receptors encode the firing patterns of CHIs in the striatum. To examine the dynamics of acetylcholine release, we used optogenetics and paired recordings from CHIs and medium spiny neurons (MSNs) virally overexpressing G-protein-activated inwardly rectifying potassium (GIRK) channels. Due to the efficient coupling between endogenous muscarinic receptors and GIRK channels, we found that firing of individual CHIs resulted in monosynaptic spontaneous inhibitory post-synaptic currents (IPSCs) in MSNs. Paired CHI-MSN recordings revealed that the high probability of acetylcholine release at these synapses allowed muscarinic receptors to faithfully encode physiological activity patterns from individual CHIs without failure. These results indicate that muscarinic receptors in striatal output neurons reliably decode CHI firing.
Topics: Acetylcholine; Ambenonium Chloride; Animals; Cholinergic Neurons; Cholinesterase Inhibitors; Corpus Striatum; Female; Humans; Inhibitory Postsynaptic Potentials; Interneurons; Male; Mice; Receptor, Muscarinic M4; Synapses
PubMed: 27373830
DOI: 10.1016/j.neuron.2016.06.021 -
The Journal of Neuroscience : the... Sep 2014Terminal Schwann cells (TSCs) are key components of the mammalian neuromuscular junction (NMJ). How the TSCs sense the synaptic activity in physiological conditions...
Terminal Schwann cells (TSCs) are key components of the mammalian neuromuscular junction (NMJ). How the TSCs sense the synaptic activity in physiological conditions remains unclear. We have taken advantage of the distinct localization of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) at the NMJ to bring out the function of different ACh receptors (AChRs). AChE is clustered by the collagen Q in the synaptic cleft and prevents the repetitive activation of muscle nicotinic AChRs. We found that BChE is anchored at the TSC by a proline-rich membrane anchor, the small transmembrane protein anchor of brain AChE. When BChE was specifically inhibited, ACh release was significant depressed through the activation of α7 nAChRs localized on the TSC and activated by the spillover of ACh. When both AChE and BChE were inhibited, the spillover increased and induced a dramatic reduction of ACh release that compromised the muscle twitch triggered by the nerve stimulation. α7 nAChRs at the TSC may act as a sensor for spillover of ACh adjusted by BChE and may represent an extrasynaptic sensor for homeostasis at the NMJ. In myasthenic rats, selective inhibition of AChE is more effective in rescuing muscle function than the simultaneous inhibition of AChE and BChE because the concomitant inhibition of BChE counteracts the positive action of AChE inhibition. These results show that inhibition of BChE should be avoided during the treatment of myasthenia and the pharmacological reversal of residual curarization after anesthesia.
Topics: Acetylcholine; Acetylcholinesterase; Ambenonium Chloride; Animals; Bungarotoxins; Butyrylcholinesterase; Cholinesterase Inhibitors; Excitatory Postsynaptic Potentials; Exocytosis; Female; Membrane Proteins; Myasthenia Gravis, Autoimmune, Experimental; Nerve Tissue Proteins; Neuromuscular Junction; Protein Binding; Rats; Schwann Cells; Terbutaline; alpha7 Nicotinic Acetylcholine Receptor
PubMed: 25186736
DOI: 10.1523/JNEUROSCI.0329-14.2014 -
The Journal of Physiology May 19711. Surplus acetylcholine (ACh) is the extra ACh that accumulates in cholinergic nerve endings when they are exposed to an anticholinesterase agent. The synthesis and...
1. Surplus acetylcholine (ACh) is the extra ACh that accumulates in cholinergic nerve endings when they are exposed to an anticholinesterase agent. The synthesis and turnover of this ACh was examined in the cat's superior cervical ganglion.2. Surplus ACh did not accumulate in chronically decentralized ganglia perfused with eserine-choline-Locke solution, and this shows that it is stored in presynaptic nerve terminals.3. Surplus ACh accumulated more rapidly in ganglia perfused with eserine than in ganglia perfused with neostigmine or with ambenonium; accumulation was delayed by 45-60 min when a quaternary anticholinesterase was used. However, the release of ACh upon preganglionic nerve stimulation was the same during perfusion with eserine, neostigmine or ambenonium. It is concluded that intracellular acetylcholinesterase normally destroys surplus ACh, whereas extracellular enzyme destroys released ACh.4. When ganglia were perfused with [(3)H]choline and eserine, the surplus ACh that accumulated was labelled but its specific radioactivity was only 38% of that of the choline added to the perfusion fluid.5. Surplus ACh was not released by nerve stimulation and was not mobilized for release during, or after, prolonged nerve stimulation. It is concluded that ACh released by nerve impulses is replaced by synthesis at the site of ACh storage and not by movement of ACh from the surplus pool.6. The accumulation of surplus ACh no more than doubled the total ACh content of ganglia, but turnover of ACh continued when the total amount was constant. Surplus ACh may contribute to spontaneous ACh output from eserinized preparations.7. When ganglia were perfused with a medium containing high K(+) (56 mM), surplus ACh was released.
Topics: Acetylcholine; Acetylcholinesterase; Ambenonium Chloride; Animals; Cats; Choline; Cholinesterase Inhibitors; Ganglia, Autonomic; Neck; Neostigmine; Nerve Endings; Perfusion; Physostigmine; Potassium; Synapses; Synaptic Transmission; Tritium
PubMed: 4325622
DOI: 10.1113/jphysiol.1971.sp009447 -
British Journal of Pharmacology May 19771 Simultaneous extracellular recordings were made from two end-plate zones of the isolated diaphragm and from the phrenic nerve of the rat in response to stimulation of...
1 Simultaneous extracellular recordings were made from two end-plate zones of the isolated diaphragm and from the phrenic nerve of the rat in response to stimulation of the nerve. The contractions of the diaphragm were also recorded.2 In the curarized diaphragm, the introduction of ecothiopate, a non-competitive inhibitor of cholinesterase, caused a threefold increase in the amplitude of the end-plate current and an eightfold increase in the duration at half the peak amplitude.3 In the non-curarized diaphragm, the introduction of ecothiopate caused the generation of repetitive activity (RA) in first the phrenic nerve: this was then followed by RA in the diaphragm. At that stage, nerve RA possessed a shorter latency than muscle RA. The generation time for nerve RA was 1.6 ms and for mRA, it was 2.7 milliseconds.4 Nerve RA was more labile than muscle RA; it was readily abolished by increasing the frequency of stimulation, by magnesium, by tubocurarine or by high concentrations of ecothiopate, whereas muscle RA was still generated. Steady exposure to acetylcholine abolished both forms of RA.5 Two competitive inhibitors of cholinesterase, neostigmine and ambenonium, were also shown to evoke RA in nerve and muscle. The generation times for nerve RA and muscle RA were similar to those following ecothiopate.6 It was concluded that nerve RA and muscle RA were generated after the inhibition of cholinesterase by ecothiopate as a result of the prolonged action of acetylcholine upon cholinoceptive sites on the nerve terminal and motor endplate respectively. A direct excitatory action of ecothiopate upon the phrenic nerve terminals was excluded.
Topics: Acetylcholine; Action Potentials; Ambenonium Chloride; Animals; Diaphragm; Drug Interactions; Echothiophate Iodide; Electric Stimulation; In Vitro Techniques; Magnesium; Muscle Contraction; Neostigmine; Neuromuscular Junction; Phrenic Nerve; Rats; Synaptic Transmission; Tubocurarine
PubMed: 195659
DOI: 10.1111/j.1476-5381.1977.tb16745.x -
Canadian Medical Association Journal Oct 1973A 50-year-old woman who initially had myasthenia gravis subsequently presented with thymoma, erythroblastopenic anemia and systemic lupus erythematosus during 17 years...
A 50-year-old woman who initially had myasthenia gravis subsequently presented with thymoma, erythroblastopenic anemia and systemic lupus erythematosus during 17 years of follow-up. In a review of the literature no similar documented cases were found, although 14 patients were reported with three of the above diseases, two also having positive LE cell tests. An association of several autoimmune disorders in one patient may be more frequent than was previously believed.
Topics: Ambenonium Chloride; Anemia, Aplastic; Autoimmune Diseases; Bone Marrow; Bone Marrow Cells; Bronchopneumonia; Eye Manifestations; Female; Hemosiderosis; Humans; Lupus Erythematosus, Discoid; Mediastinal Cyst; Middle Aged; Myasthenia Gravis; Neostigmine; Neutrophils; Prednisone; Recurrence; Reticulocytes; Thymoma; Thymus Gland; Thymus Neoplasms
PubMed: 4126868
DOI: No ID Found -
Journal of Neurochemistry Dec 2013Long-term nicotine exposure induces alterations in dopamine transmission in nucleus accumbens that sustain the reinforcing effects of smoking. One approach to understand...
Long-term nicotine exposure induces alterations in dopamine transmission in nucleus accumbens that sustain the reinforcing effects of smoking. One approach to understand the adaptive changes that arise involves measurement of endogenous dopamine release using voltammetry. We therefore treated rats for 2-3 months with nicotine and examined alterations in nAChR subtype expression and electrically evoked dopamine release in rat nucleus accumbens shell, a region key in addiction. Long-term nicotine treatment selectively decreased stimulated α6β2* nAChR-mediated dopamine release compared with vehicle-treated rats. It also reduced α6β2* nAChRs, suggesting the receptor decline may contribute to the functional loss. This decreased response in release after chronic nicotine treatment was still partially sensitive to the agonist nicotine. Studies with an acetylcholinesterase inhibitor demonstrated that the response was also sensitive to increased endogenous acetylcholine. However, unlike the agonists, nAChR antagonists decreased dopamine release only in vehicle- but not nicotine-treated rats. As antagonists function by blocking the action of acetylcholine, their ineffectiveness suggests that reduced acetylcholine levels partly underlie the dampened α6β2* nAChR-mediated function in nicotine-treated rats. As long-term nicotine modifies dopamine release by decreasing α6β2* nAChRs and their function, these data suggest that interventions that target this subtype may be useful for treating nicotine dependence. Long-term nicotine treatment decreases dopamine (DA) transmission in the mesolimbic dopaminergic system. Our data suggest this may involve a decrease in α6β2* nicotinic receptor expression and function. These changes may play a key role in nicotine reward and dependence.
Topics: Ambenonium Chloride; Animals; Cholinesterase Inhibitors; Dopamine; Dopamine Plasma Membrane Transport Proteins; Down-Regulation; Electric Stimulation; Male; Nicotine; Nicotinic Agonists; Nicotinic Antagonists; Nucleus Accumbens; Rats; Rats, Sprague-Dawley; Receptors, Nicotinic; Time Factors
PubMed: 23992036
DOI: 10.1111/jnc.12442 -
British Journal of Anaesthesia Oct 1968
Comparative Study
Topics: Acetylcholine; Ambenonium Chloride; Animals; Anura; Curare; Diaphragm; Drug Synergism; Edrophonium; Heart; Heart Arrest; In Vitro Techniques; Mice; Muscles; Neostigmine; Physostigmine; Rabbits; Rats; Stimulation, Chemical; Toxiferine; Tubocurarine
PubMed: 5698527
DOI: 10.1093/bja/40.10.730