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Mediators of Inflammation 2019Recent studies have shown that acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) may serve as important diagnostic and therapeutic targets in sepsis. Since...
In Vivo Effects of Neostigmine and Physostigmine on Neutrophil Functions and Evaluation of Acetylcholinesterase and Butyrylcholinesterase as Inflammatory Markers during Experimental Sepsis in Rats.
INTRODUCTION
Recent studies have shown that acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) may serve as important diagnostic and therapeutic targets in sepsis. Since polymorphonuclear neutrophils (PMNs) play a pivotal role in the early phase of sepsis, we evaluated the potential therapeutic effects of cholinesterase inhibitors on PMN functions during cecal ligation and puncture- (CLP-) induced sepsis and investigated the roles of AChE and BChE as inflammatory markers under standardized experimental conditions.
METHODS
Sham surgery or CLP was performed in male Wistar rats ( = 60). Animals were randomized into four groups: physostigmine, 100 g/kg; neostigmine, 75 g/kg; 0.9% saline (control group); and sham group, each applied four times over 24 h. The levels of reactive oxygen species (ROS) production and CD11b/CD62l expression were quantified by flow cytometry at = 0, 6, 15, 20, and 24 h. Blood gas analysis as well as AChE and BChE activity levels was measured by validated point-of-care measurements. Clinical scores and survival times were determined.
RESULTS
CLP induced a significant increase in ROS production and CD11b upregulation by rat PMNs. Treatment with physostigmine or neostigmine significantly reduced ROS production and CD11b upregulation by PMNs 20 h after CLP induction. In physostigmine-treated animals, survival times were significantly improved compared to the control animals, but not in neostigmine-treated animals. While AChE activity significantly decreased in the control animals at > 6 h, AChE activity did not change in the sham group. BChE activity decreased at > 20 h in the control animals.
CONCLUSION
While AChE activity may serve as an acute inflammatory marker, BChE activity shows a delayed decrease. Administration of centrally acting physostigmine in CLP-induced sepsis in rats has protective effects on PMN functions and improves survival times, which may be of interest in clinical practice.
Topics: Acetylcholinesterase; Animals; Biomarkers; Blood Gas Analysis; Butyrylcholinesterase; Male; Neostigmine; Neutrophils; Physostigmine; Rats; Rats, Wistar; Reactive Oxygen Species; Sepsis
PubMed: 30804708
DOI: 10.1155/2019/8274903 -
Toxicology Mar 2019Carbamates physostigmine and pyridostigmine have been used as a pretreatment against poisoning with nerve agents in order to reversibly inhibit and thus protect from... (Comparative Study)
Comparative Study
BACKGROUND
Carbamates physostigmine and pyridostigmine have been used as a pretreatment against poisoning with nerve agents in order to reversibly inhibit and thus protect from irreversible inhibition a portion of acetylcholinesterase (AChE) in brain and respiratory muscles that is crucial for survival. Memantine, an adamantine derivative, has emerged as a promising alternative to carbamates, since it prevented the fasciculations and skeletal muscle necrosis induced by carbamates and organophosphates, including nerve agents.
AIM
This experimental study was undertaken in order to investigate and compare the protective and behavioural effects of memantine and standard carbamates physostigmine and pyridostigmine in rats poisoned with soman and treated with atropine, oxime HI-6 and diazepam. Another goal was to elucidate the mechanisms of the antidotal effect of memantine and its potential synergism with standard antidotes against nerve agents.
MATERIALS AND METHODS
Male Wistar rats were used throughout the experiments. In dose-finding experiments memantine was administered at dose interval 0-72 mg/kg sc 60 min before sc injection of soman. In time-finding experiments memantine was injected 18 mg/kg sc 0-1440 min before soman. Standard treatment antidotes - atropine 10 mg/kg, HI-6 50 mg/kg and diazepam 2.5 mg/kg - were administered im within 15 s post-exposure. Soman 0.75 LD was used to study its inhibitions of neuromuscular transmission on the phrenic nerve-diaphragm preparation in situ and of tissue AChE activity. Behavioural effects of the prophylactic antidotes were investigated by means of the rotarod test. Based on these data therapeutic index and therapeutic width was calculated for all three prophylactic agents.
RESULTS
Memantine pretreatment (18 mg/kg sc) produced in rats poisoned with soman significantly better protective ratios (PRs) than the two carbamates - 1.25 when administered alone and 2.3 when combined with atropine pretreatment and 6.33 and 7.23 with atropine/HI-6 and atropine/HI-6/diazepam post-exposure therapy, respectively. The highest PR of 10.11 obtained in Atr/HI-6-treated rats was achieved after pretreatment with memantine 36 mg/kg. This additional protection lasted for 8 h. All three prophylactic regimens antagonised the soman-induced neuromuscular blockade, but the effect of memantine was fastest. Pretreatment with memantine assured higher AChE activity in brain and diaphragm than in unpretreated rats (46% vs 28% and 68% vs. 38%, respectively). All three prophylactic regimens affected the rotarod performance in rats, but the effect of memantine was relatively strongest. Memantine and pyridostigmine had lowest and highest therapeutic index and therapeutic width, respectively.
CONCLUSIONS
Although memantine assures better and longer-lasting protection against soman poisoning in rats than the two carbamates, its small therapeutic index and narrow therapeutic width seriously limit its potential as a pretreatment agent. Despite its behavioural effects, memantine seems to be beneficial antidote when administered after soman, along with atropine/HI-6/diazepam therapy. Mechanism of the antidotal effect of memantine against soman poisoning appears to be a combination of AChE-protecting and NMDA receptor-blocking action.
Topics: Acetylcholinesterase; Animals; Antidotes; Atropine; Behavior, Animal; Chemical Warfare Agents; Cholinesterase Inhibitors; Diazepam; Disease Models, Animal; Drug Synergism; Drug Therapy, Combination; GPI-Linked Proteins; Male; Memantine; Neuromuscular Junction; Organophosphate Poisoning; Oximes; Pyridinium Compounds; Rats, Wistar; Receptors, N-Methyl-D-Aspartate; Soman; Synaptic Transmission
PubMed: 30682440
DOI: 10.1016/j.tox.2019.01.012 -
Molecules (Basel, Switzerland) Mar 2020Organophosphates (OPCs), useful agents as pesticides, also represent a serious health hazard. Standard therapy with atropine and established oxime-type enzyme...
AIMS
Organophosphates (OPCs), useful agents as pesticides, also represent a serious health hazard. Standard therapy with atropine and established oxime-type enzyme reactivators is unsatisfactory. Experimental data indicate that superior therapeutic results can be obtained when reversible cholinesterase inhibitors are administered before OPC exposure. Comparing the protective efficacy of five such cholinesterase inhibitors (physostigmine, pyridostigmine, ranitidine, tacrine, or K-27), we observed best protection for the experimental oxime K-27. The present study was undertaken in order to determine if additional administration of K-27 immediately after OPC (paraoxon) exposure can improve the outcome.
METHODS
Therapeutic efficacy was assessed in rats by determining the relative risk of death (RR) by Cox survival analysis over a period of 48 h. Animals that received only pretreatment and paraoxon were compared with those that had received pretreatment and paraoxon followed by K-27 immediately after paraoxon exposure.
RESULTS
Best protection from paraoxon-induced mortality was observed after pretreatment with physostigmine (RR = 0.30) and K-27 (RR = 0.34). Both substances were significantly more efficacious than tacrine (RR = 0.67), ranitidine (RR = 0.72), and pyridostigmine (RR = 0.76), which were less efficacious but still significantly reduced the RR compared to the no-treatment group (paraoxon only). Additional administration of K-27 immediately after paraoxon exposure (posttreatment) did not further reduce mortality. Statistical analysis between pretreatment before paraoxon exposure alone and pretreatment plus K-27 posttreatment did not show any significant difference for any of the pretreatment regimens.
CONCLUSIONS
Best outcome is achieved if physostigmine or K-27 are administered prophylactically before exposure to sublethal paraoxon dosages. Therapeutic outcome is not further improved by additional oxime therapy immediately thereafter.
Topics: Animals; Cholinesterase Inhibitors; Cholinesterase Reactivators; Male; Organophosphates; Oximes; Paraoxon; Physostigmine; Post-Exposure Prophylaxis; Pre-Exposure Prophylaxis; Proportional Hazards Models; Pyridostigmine Bromide; Ranitidine; Rats; Rats, Wistar; Survival Analysis; Tacrine
PubMed: 32230733
DOI: 10.3390/molecules25071521 -
Chemico-biological Interactions Feb 2023Phthalates are widely used plasticizers that are primarily and rapidly metabolized to monoester phthalates in mammals. In the present study, the hydrolysis of dibutyl...
Hydrolysis of dibutyl phthalate and di(2-ethylhexyl) phthalate in human liver, small intestine, kidney, and lung: An in vitro analysis using organ subcellular fractions and recombinant carboxylesterases.
Phthalates are widely used plasticizers that are primarily and rapidly metabolized to monoester phthalates in mammals. In the present study, the hydrolysis of dibutyl phthalate (DBP) and di(2-ethylhexyl) phthalate (DEHP) in the human liver, small intestine, kidney, and lung was examined by the catalytic, kinetic, and inhibition analyses using organ microsomal and cytosolic fractions and recombinant carboxylesterases (CESs). The V (y-intercept) values based on the Eadie-Hofstee plots of DBP hydrolysis were liver > small intestine > kidney > lung in microsomes, and liver > small intestine > lung > kidney in cytosol, respectively. The CL values (x-intercept) were small intestine > liver > kidney > lung in both microsomes and cytosol. The V and CL or CL values of DEHP hydrolysis were small intestine > liver > kidney > lung in both microsomes and cytosol. Bis(4-nitrophenyl) phosphate (BNPP) effectively inhibited the activities of DBP and DEHP hydrolysis in the microsomes and cytosol of liver, small intestine, kidney, and lung. Although physostigmine also potently inhibited DBP and DEHP hydrolysis activities in both the microsomes and cytosol of the small intestine and kidney, the inhibitory effects in the liver and lung were weak. In recombinant CESs, the V values of DBP hydrolysis were CES1 (CES1b, CES1c) > CES2, whereas the CL values were CES2 > CES1 (CES1b, CES1c). On the other hand, the V and CL values of DEHP hydrolysis were CES2 > CES1 (CES1b, CES1c). These results suggest an extensive organ-dependence of DBP and DEHP hydrolysis due to CES expression, and that CESs are responsible for the metabolic activation of phthalates.
Topics: Animals; Humans; Dibutyl Phthalate; Carboxylic Ester Hydrolases; Diethylhexyl Phthalate; Hydrolysis; Liver; Intestine, Small; Microsomes; Kidney; Lung; Mammals
PubMed: 36657734
DOI: 10.1016/j.cbi.2023.110353 -
Neurology Feb 2021Henry R. Viets (1890-1969) was both a noted neurologist and medical historian. While at Harvard Medical School, from which he graduated in 1916, he attracted the...
Henry R. Viets (1890-1969) was both a noted neurologist and medical historian. While at Harvard Medical School, from which he graduated in 1916, he attracted the attention of Harvey Cushing who directed Viets into these disciplines. Cushing arranged for Viets to take a fellowship in Oxford in the year after his graduation. With Cushing's recommendation, he lived with Sir William and Lady Osler and did research with the famous neurologist Sir Charles Sherrington. Viets was in London in 1935 when he heard about the remarkable success of Mary Walker in treating myasthenia gravis, first with physostigmine and then with neostigmine (Prostigmin). Securing an ampoule of this drug, he took it to the Massachusetts General Hospital where he was an attending neurologist and in March 1935 injected it into a myasthenic patient with great success. He established the first Myasthenia Gravis clinic in the world and was a pioneer in the treatment of this once obscure disease; he evaluated hundreds of patients and published many articles on myasthenia. He continued this association for more than 30 years. Under the tutelage of Cushing and Osler, Viets became a medical historian and bibliophile, publishing hundreds of articles and several books on many different subjects in the history of medicine. He was a president of the American Association for the History of Medicine and curator of the Boston Medical Library that eventually joined with the Harvard Medical School Library. Viets served on the Editorial Board of the for 40 years.
Topics: History, 20th Century; Humans; London; Massachusetts; Myasthenia Gravis; Neurology
PubMed: 33219137
DOI: 10.1212/WNL.0000000000011239 -
Journal of Medical Toxicology :... Apr 2023Recurrent physostigmine shortages present a challenge to healthcare providers treating antimuscarinic delirium. Other centrally acting acetylcholinesterase inhibitors...
INTRODUCTION
Recurrent physostigmine shortages present a challenge to healthcare providers treating antimuscarinic delirium. Other centrally acting acetylcholinesterase inhibitors such as rivastigmine may represent a therapeutic alternative or adjunct during physostigmine shortage; however, previous reports of use have not documented serum antimuscarinic toxin concentrations, limiting evaluation of effectiveness. Combination therapy with physostigmine and rivastigmine has not been described. In this report, the authors present a case of diphenhydramine-induced antimuscarinic delirium with elevated diphenhydramine serum concentrations treated with physostigmine and transdermal rivastigmine without observed adverse effect.
CASE REPORT
A 48-year-old female presented to an emergency department after ingesting 3.75 g (41.2 mg/kg) of diphenhydramine. She had antimuscarinic delirium with a presenting serum diphenhydramine concentration of 1500 ng/mL (therapeutic range, 25-112 ng/mL) and required two doses of physostigmine to avert intubation prior to intensive care unit (ICU) admission. At hospital hour 22, in the ICU, antimuscarinic delirium persisted but no further physostigmine was available due to hospital shortage. Therefore, a 9.5-mg transdermal rivastigmine patch was applied. By hospital hour 24, her delirium had resolved. A serum diphenhydramine concentration at hospital hour 25 was elevated at 760 ng/mL. Transdermal rivastigmine was discontinued at hospital hour 48 without recurrent delirium. Despite persistent normal mental status after rivastigmine discontinuation, the patient had a dry mouth, difficulty urinating, and mydriasis until hospital day 5. She never developed muscarinic toxicity.
DISCUSSION
Transdermal rivastigmine may be a useful treatment alternative or adjunct during physostigmine shortage for antimuscarinic delirium and has a long duration of action without aspiration risk. Muscarinic toxicity was not observed.
Topics: Humans; Female; Middle Aged; Physostigmine; Muscarinic Antagonists; Rivastigmine; Acetylcholinesterase; Cholinesterase Inhibitors; Delirium
PubMed: 36575250
DOI: 10.1007/s13181-022-00925-z -
Pesticide Biochemistry and Physiology May 2016AChE is the target of organophosphate (OP) and carbamate (CB) pesticides, and mutations in the gene can significantly reduce insects' sensitivity to these pesticides....
AChE is the target of organophosphate (OP) and carbamate (CB) pesticides, and mutations in the gene can significantly reduce insects' sensitivity to these pesticides. Bombyx mori is highly sensitive to pesticides. To investigate the effects of mutations on AChE1 structure and function, we used a prokaryotic system to express B.mori wild type AChE1 (wAChE1) and mutant AChE1 (mAChE1) in this study. Active AChE1 proteins were obtained after refolding and purification, and wAChE1 and mAChE1 had similar activities. After incubation with 10(-6)M physostigmine and 10(-3)mg/mL phoxim, the remaining enzyme activity of mAChE1 was 4.42% and 8.86% higher than that of wAChE1's, respectively. Three-dimensional analysis of mutation AChE1 (mAChE1) revealed that the Ser and Ala side chains extended toward the central part of S285 with distances of just 2.80Å and 3.68Å, respectively, which changed the spatial structure of the active center and reduced its sensitivity to pesticides. These results indicated that the mutations altered the 3D structure of AChE1, which may affect the binding of physostigmine and phoxim to the serine residue at the active center, leading to reduced sensitivity. Our study helps understand the relationship between AChE1 mutations and pesticide resistance and provides a new direction for the cultivation of new pesticide-resistant varieties of B.mori.
Topics: Acetylcholinesterase; Animals; Bombyx; Models, Molecular; Mutation; Plasmids
PubMed: 27017875
DOI: 10.1016/j.pestbp.2015.11.003 -
Experimental & Applied Acarology Jun 2021The non-target toxicity and resistance problems of acetylcholinesterase (AChE) insecticides, such as organophosphates and carbamates, are of growing concern. To explore...
The non-target toxicity and resistance problems of acetylcholinesterase (AChE) insecticides, such as organophosphates and carbamates, are of growing concern. To explore the potential targets for achieving inhibitor selectivity, the AChE structures at or near the catalytic pocket of Tetranychus urticae (TuAChE), honey bees, and humans were compared. The entrances to the AChE catalytic pocket differ significantly because of their different peripheral sites. The role of these potential mite-specific sites in AChE function was further elucidated by site-directed mutagenesis of these sites and then examining the catalytic activities of TuAChE mutants. The spider mite E, H, and V active sites are important for AChE function. By further analyzing their physostigmine inhibitory properties and the detailed interaction between physostigmine and TuAChE, the peripheral site H locating near the gorge entrance, and S at the oxyanion hole, affects substrate and inhibitor trafficking. The discovery of conserved mite-specific residues in Tetranychus will enable the development of safer, effective pesticides that target residues present only in mite AChEs, potentially offering effective control against this important agricultural pest.
Topics: Acetylcholinesterase; Animals; Carbamates; Insecticides; Mites; Tetranychidae
PubMed: 33914192
DOI: 10.1007/s10493-021-00624-4 -
Brain Research Dec 2017Stroke commonly leads to adult disability and death worldwide. Its major symptoms are spastic hemiplegia and discordant motion, consequent to neuronal cell death induced...
Stroke commonly leads to adult disability and death worldwide. Its major symptoms are spastic hemiplegia and discordant motion, consequent to neuronal cell death induced by brain vessel occlusion. Acetylcholinesterase (AChE) is upregulated and allied with inflammation and apoptosis after stroke. Recent studies suggest that AChE inhibition ameliorates ischemia-reperfusion injury and has neuroprotective properties. (-)-Phenserine, a reversible AChE inhibitor, has a broad range of actions independent of its AChE properties, including neuroprotective ones. However, its protective effects and detailed mechanism of action in the rat middle cerebral artery occlusion model (MCAO) remain to be elucidated. This study investigated the therapeutic effects of (-)-phenserine for stroke in the rat focal cerebral ischemia model and oxygen-glucose deprivation/reperfusion (OGD/RP) damage model in SH-SY5Y neuronal cultures. (-)-Phenserine mitigated OGD/PR-induced SH-SY5Y cell death, providing an inverted U-shaped dose-response relationship between concentration and survival. In MCAO challenged rats, (-)-phenserine reduced infarction volume, cell death and improved body asymmetry, a behavioral measure of stoke impact. In both cellular and animal studies, (-)-phenserine elevated brain-derived neurotrophic factor (BDNF) and B-cell lymphoma 2 (Bcl-2) levels, and decreased activated-caspase 3, amyloid precursor protein (APP) and glial fibrillary acidic protein (GFAP) expression, potentially mediated through the ERK-1/2 signaling pathway. These actions mitigated neuronal apoptosis in the stroke penumbra, and decreased matrix metallopeptidase-9 (MMP-9) expression. In synopsis, (-)-phenserine significantly reduced neuronal damage induced by ischemia/reperfusion injury in a rat model of MCAO and cellular model of OGD/RP, demonstrating that its anti-apoptotic/neuroprotective/neurotrophic cholinergic and non-cholinergic properties warrant further evaluation in conditions of brain injury.
Topics: Animals; Apoptosis; Brain Ischemia; Cell Hypoxia; Cell Line, Tumor; Cell Survival; Cholinesterase Inhibitors; Dose-Response Relationship, Drug; Glucose; Humans; Male; Neurons; Neuroprotective Agents; Physostigmine; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Stroke
PubMed: 28963051
DOI: 10.1016/j.brainres.2017.09.015 -
Neuroscience and Biobehavioral Reviews Dec 2016The threat of chemical warfare agents like nerve agents requires life saving measures of medical pretreatment combined with treatment after exposure. Pretreatment... (Review)
Review
The threat of chemical warfare agents like nerve agents requires life saving measures of medical pretreatment combined with treatment after exposure. Pretreatment (pyridostigmine) may cause some side effects in a small number of individuals. A comprehensive research on animals has been performed to clarify effects on behavior. The results from these studies are far from unambiguous, since pyridostigmine may produce adverse effects on behavior in animals in relatively high doses, but not in a consistent way. Other animal studies have examined the potential of drugs like physostigmine, galantamine, benactyzine, trihexyphenidyl, and procyclidine, but they all produce marked behavioral impairment at doses sufficient to contribute to protection against a convulsant dose of soman. Attempts have also been made to develop a combination of drugs capable of assuring full protection (prophylaxis) against nerve agents. However, common to all combinations is that they at anticonvulsant doses cause behavioral deficits. Therefore, the use of limited pretreatment doses may be performed without marked side effects followed by post-exposure therapy with a combination of drugs.
Topics: Animals; Benactyzine; Cholinesterase Inhibitors; Humans; Nerve Agents; Procyclidine; Soman
PubMed: 27773692
DOI: 10.1016/j.neubiorev.2016.10.017